fs/btrfs/volumes.c

   1 /*
   2  * Copyright (C) 2007 Oracle.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18 #include <linux/sched.h>
  19 #include <linux/bio.h>
  20 #include <linux/slab.h>
  21 #include <linux/buffer_head.h>
  22 #include <linux/blkdev.h>
  23 #include <linux/random.h>
  24 #include <linux/iocontext.h>
  25 #include <linux/capability.h>
  26 #include <linux/ratelimit.h>
  27 #include <linux/kthread.h>
  28 #include "compat.h"
  29 #include "ctree.h"
  30 #include "extent_map.h"
  31 #include "disk-io.h"
  32 #include "transaction.h"
  33 #include "print-tree.h"
  34 #include "volumes.h"
  35 #include "async-thread.h"
  36 #include "check-integrity.h"
  37 #include "rcu-string.h"
  38 #include "math.h"
  39 #include "dev-replace.h"
  40
  41 static int init_first_rw_device(struct btrfs_trans_handle *trans,
  42                                 struct btrfs_root *root,
  43                                 struct btrfs_device *device);
  44 static int btrfs_relocate_sys_chunks(struct btrfs_root *root);
  45 static void __btrfs_reset_dev_stats(struct btrfs_device *dev);
  46 static void btrfs_dev_stat_print_on_load(struct btrfs_device *device);
  47
  48 static DEFINE_MUTEX(uuid_mutex);
  49 static LIST_HEAD(fs_uuids);
  50
  51 static void lock_chunks(struct btrfs_root *root)
  52 {
  53         mutex_lock(&root->fs_info->chunk_mutex);
  54 }
  55
  56 static void unlock_chunks(struct btrfs_root *root)
  57 {
  58         mutex_unlock(&root->fs_info->chunk_mutex);
  59 }
  60
  61 static void free_fs_devices(struct btrfs_fs_devices *fs_devices)
  62 {
  63         struct btrfs_device *device;
  64         WARN_ON(fs_devices->opened);
  65         while (!list_empty(&fs_devices->devices)) {
  66                 device = list_entry(fs_devices->devices.next,
  67                                     struct btrfs_device, dev_list);
  68                 list_del(&device->dev_list);
  69                 rcu_string_free(device->name);
  70                 kfree(device);
  71         }
  72         kfree(fs_devices);
  73 }
  74
  75 static void btrfs_kobject_uevent(struct block_device *bdev,
  76                                  enum kobject_action action)
  77 {
  78         int ret;
  79
  80         ret = kobject_uevent(&disk_to_dev(bdev->bd_disk)->kobj, action);
  81         if (ret)
  82                 pr_warn("Sending event '%d' to kobject: '%s' (%p): failed\n",
  83                         action,
  84                         kobject_name(&disk_to_dev(bdev->bd_disk)->kobj),
  85                         &disk_to_dev(bdev->bd_disk)->kobj);
  86 }
  87
  88 void btrfs_cleanup_fs_uuids(void)
  89 {
  90         struct btrfs_fs_devices *fs_devices;
  91
  92         while (!list_empty(&fs_uuids)) {
  93                 fs_devices = list_entry(fs_uuids.next,
  94                                         struct btrfs_fs_devices, list);
  95                 list_del(&fs_devices->list);
  96                 free_fs_devices(fs_devices);
  97         }
  98 }
  99
 100 static noinline struct btrfs_device *__find_device(struct list_head *head,
 101                                                    u64 devid, u8 *uuid)
 102 {
 103         struct btrfs_device *dev;
 104
 105         list_for_each_entry(dev, head, dev_list) {
 106                 if (dev->devid == devid &&
 107                     (!uuid || !memcmp(dev->uuid, uuid, BTRFS_UUID_SIZE))) {
 108                         return dev;
 109                 }
 110         }
 111         return NULL;
 112 }
 113
 114 static noinline struct btrfs_fs_devices *find_fsid(u8 *fsid)
 115 {
 116         struct btrfs_fs_devices *fs_devices;
 117
 118         list_for_each_entry(fs_devices, &fs_uuids, list) {
 119                 if (memcmp(fsid, fs_devices->fsid, BTRFS_FSID_SIZE) == 0)
 120                         return fs_devices;
 121         }
 122         return NULL;
 123 }
 124
 125 static int
 126 btrfs_get_bdev_and_sb(const char *device_path, fmode_t flags, void *holder,
 127                       int flush, struct block_device **bdev,
 128                       struct buffer_head **bh)
 129 {
 130         int ret;
 131
 132         *bdev = blkdev_get_by_path(device_path, flags, holder);
 133
 134         if (IS_ERR(*bdev)) {
 135                 ret = PTR_ERR(*bdev);
 136                 printk(KERN_INFO "btrfs: open %s failed\n", device_path);
 137                 goto error;
 138         }
 139
 140         if (flush)
 141                 filemap_write_and_wait((*bdev)->bd_inode->i_mapping);
 142         ret = set_blocksize(*bdev, 4096);
 143         if (ret) {
 144                 blkdev_put(*bdev, flags);
 145                 goto error;
 146         }
 147         invalidate_bdev(*bdev);
 148         *bh = btrfs_read_dev_super(*bdev);
 149         if (!*bh) {
 150                 ret = -EINVAL;
 151                 blkdev_put(*bdev, flags);
 152                 goto error;
 153         }
 154
 155         return 0;
 156
 157 error:
 158         *bdev = NULL;
 159         *bh = NULL;
 160         return ret;
 161 }
 162
 163 static void requeue_list(struct btrfs_pending_bios *pending_bios,
 164                         struct bio *head, struct bio *tail)
 165 {
 166
 167         struct bio *old_head;
 168
 169         old_head = pending_bios->head;
 170         pending_bios->head = head;
 171         if (pending_bios->tail)
 172                 tail->bi_next = old_head;
 173         else
 174                 pending_bios->tail = tail;
 175 }
 176
 177 /*
 178  * we try to collect pending bios for a device so we don't get a large
 179  * number of procs sending bios down to the same device.  This greatly
 180  * improves the schedulers ability to collect and merge the bios.
 181  *
 182  * But, it also turns into a long list of bios to process and that is sure
 183  * to eventually make the worker thread block.  The solution here is to
 184  * make some progress and then put this work struct back at the end of
 185  * the list if the block device is congested.  This way, multiple devices
 186  * can make progress from a single worker thread.
 187  */
 188 static noinline void run_scheduled_bios(struct btrfs_device *device)
 189 {
 190         struct bio *pending;
 191         struct backing_dev_info *bdi;
 192         struct btrfs_fs_info *fs_info;
 193         struct btrfs_pending_bios *pending_bios;
 194         struct bio *tail;
 195         struct bio *cur;
 196         int again = 0;
 197         unsigned long num_run;
 198         unsigned long batch_run = 0;
 199         unsigned long limit;
 200         unsigned long last_waited = 0;
 201         int force_reg = 0;
 202         int sync_pending = 0;
 203         struct blk_plug plug;
 204
 205         /*
 206          * this function runs all the bios we've collected for
 207          * a particular device.  We don't want to wander off to
 208          * another device without first sending all of these down.
 209          * So, setup a plug here and finish it off before we return
 210          */
 211         blk_start_plug(&plug);
 212
 213         bdi = blk_get_backing_dev_info(device->bdev);
 214         fs_info = device->dev_root->fs_info;
 215         limit = btrfs_async_submit_limit(fs_info);
 216         limit = limit * 2 / 3;
 217
 218 loop:
 219         spin_lock(&device->io_lock);
 220
 221 loop_lock:
 222         num_run = 0;
 223
 224         /* take all the bios off the list at once and process them
 225          * later on (without the lock held).  But, remember the
 226          * tail and other pointers so the bios can be properly reinserted
 227          * into the list if we hit congestion
 228          */
 229         if (!force_reg && device->pending_sync_bios.head) {
 230                 pending_bios = &device->pending_sync_bios;
 231                 force_reg = 1;
 232         } else {
 233                 pending_bios = &device->pending_bios;
 234                 force_reg = 0;
 235         }
 236
 237         pending = pending_bios->head;
 238         tail = pending_bios->tail;
 239         WARN_ON(pending && !tail);
 240
 241         /*
 242          * if pending was null this time around, no bios need processing
 243          * at all and we can stop.  Otherwise it'll loop back up again
 244          * and do an additional check so no bios are missed.
 245          *
 246          * device->running_pending is used to synchronize with the
 247          * schedule_bio code.
 248          */
 249         if (device->pending_sync_bios.head == NULL &&
 250             device->pending_bios.head == NULL) {
 251                 again = 0;
 252                 device->running_pending = 0;
 253         } else {
 254                 again = 1;
 255                 device->running_pending = 1;
 256         }
 257
 258         pending_bios->head = NULL;
 259         pending_bios->tail = NULL;
 260
 261         spin_unlock(&device->io_lock);
 262
 263         while (pending) {
 264
 265                 rmb();
 266                 /* we want to work on both lists, but do more bios on the
 267                  * sync list than the regular list
 268                  */
 269                 if ((num_run > 32 &&
 270                     pending_bios != &device->pending_sync_bios &&
 271                     device->pending_sync_bios.head) ||
 272                    (num_run > 64 && pending_bios == &device->pending_sync_bios &&
 273                     device->pending_bios.head)) {
 274                         spin_lock(&device->io_lock);
 275                         requeue_list(pending_bios, pending, tail);
 276                         goto loop_lock;
 277                 }
 278
 279                 cur = pending;
 280                 pending = pending->bi_next;
 281                 cur->bi_next = NULL;
 282
 283                 if (atomic_dec_return(&fs_info->nr_async_bios) < limit &&
 284                     waitqueue_active(&fs_info->async_submit_wait))
 285                         wake_up(&fs_info->async_submit_wait);
 286
 287                 BUG_ON(atomic_read(&cur->bi_cnt) == 0);
 288
 289                 /*
 290                  * if we're doing the sync list, record that our
 291                  * plug has some sync requests on it
 292                  *
 293                  * If we're doing the regular list and there are
 294                  * sync requests sitting around, unplug before
 295                  * we add more
 296                  */
 297                 if (pending_bios == &device->pending_sync_bios) {
 298                         sync_pending = 1;
 299                 } else if (sync_pending) {
 300                         blk_finish_plug(&plug);
 301                         blk_start_plug(&plug);
 302                         sync_pending = 0;
 303                 }
 304
 305                 btrfsic_submit_bio(cur->bi_rw, cur);
 306                 num_run++;
 307                 batch_run++;
 308                 if (need_resched())
 309                         cond_resched();
 310
 311                 /*
 312                  * we made progress, there is more work to do and the bdi
 313                  * is now congested.  Back off and let other work structs
 314                  * run instead
 315                  */
 316                 if (pending && bdi_write_congested(bdi) && batch_run > 8 &&
 317                     fs_info->fs_devices->open_devices > 1) {
 318                         struct io_context *ioc;
 319
 320                         ioc = current->io_context;
 321
 322                         /*
 323                          * the main goal here is that we don't want to
 324                          * block if we're going to be able to submit
 325                          * more requests without blocking.
 326                          *
 327                          * This code does two great things, it pokes into
 328                          * the elevator code from a filesystem _and_
 329                          * it makes assumptions about how batching works.
 330                          */
 331                         if (ioc && ioc->nr_batch_requests > 0 &&
 332                             time_before(jiffies, ioc->last_waited + HZ/50UL) &&
 333                             (last_waited == 0 ||
 334                              ioc->last_waited == last_waited)) {
 335                                 /*
 336                                  * we want to go through our batch of
 337                                  * requests and stop.  So, we copy out
 338                                  * the ioc->last_waited time and test
 339                                  * against it before looping
 340                                  */
 341                                 last_waited = ioc->last_waited;
 342                                 if (need_resched())
 343                                         cond_resched();
 344                                 continue;
 345                         }
 346                         spin_lock(&device->io_lock);
 347                         requeue_list(pending_bios, pending, tail);
 348                         device->running_pending = 1;
 349
 350                         spin_unlock(&device->io_lock);
 351                         btrfs_requeue_work(&device->work);
 352                         goto done;
 353                 }
 354                 /* unplug every 64 requests just for good measure */
 355                 if (batch_run % 64 == 0) {
 356                         blk_finish_plug(&plug);
 357                         blk_start_plug(&plug);
 358                         sync_pending = 0;
 359                 }
 360         }
 361
 362         cond_resched();
 363         if (again)
 364                 goto loop;
 365
 366         spin_lock(&device->io_lock);
 367         if (device->pending_bios.head || device->pending_sync_bios.head)
 368                 goto loop_lock;
 369         spin_unlock(&device->io_lock);
 370
 371 done:
 372         blk_finish_plug(&plug);
 373 }
 374
 375 static void pending_bios_fn(struct btrfs_work *work)
 376 {
 377         struct btrfs_device *device;
 378
 379         device = container_of(work, struct btrfs_device, work);
 380         run_scheduled_bios(device);
 381 }
 382
 383 static noinline int device_list_add(const char *path,
 384                            struct btrfs_super_block *disk_super,
 385                            u64 devid, struct btrfs_fs_devices **fs_devices_ret)
 386 {
 387         struct btrfs_device *device;
 388         struct btrfs_fs_devices *fs_devices;
 389         struct rcu_string *name;
 390         u64 found_transid = btrfs_super_generation(disk_super);
 391
 392         fs_devices = find_fsid(disk_super->fsid);
 393         if (!fs_devices) {
 394                 fs_devices = kzalloc(sizeof(*fs_devices), GFP_NOFS);
 395                 if (!fs_devices)
 396                         return -ENOMEM;
 397                 INIT_LIST_HEAD(&fs_devices->devices);
 398                 INIT_LIST_HEAD(&fs_devices->alloc_list);
 399                 list_add(&fs_devices->list, &fs_uuids);
 400                 memcpy(fs_devices->fsid, disk_super->fsid, BTRFS_FSID_SIZE);
 401                 fs_devices->latest_devid = devid;
 402                 fs_devices->latest_trans = found_transid;
 403                 mutex_init(&fs_devices->device_list_mutex);
 404                 device = NULL;
 405         } else {
 406                 device = __find_device(&fs_devices->devices, devid,
 407                                        disk_super->dev_item.uuid);
 408         }
 409         if (!device) {
 410                 if (fs_devices->opened)
 411                         return -EBUSY;
 412
 413                 device = kzalloc(sizeof(*device), GFP_NOFS);
 414                 if (!device) {
 415                         /* we can safely leave the fs_devices entry around */
 416                         return -ENOMEM;
 417                 }
 418                 device->devid = devid;
 419                 device->dev_stats_valid = 0;
 420                 device->work.func = pending_bios_fn;
 421                 memcpy(device->uuid, disk_super->dev_item.uuid,
 422                        BTRFS_UUID_SIZE);
 423                 spin_lock_init(&device->io_lock);
 424
 425                 name = rcu_string_strdup(path, GFP_NOFS);
 426                 if (!name) {
 427                         kfree(device);
 428                         return -ENOMEM;
 429                 }
 430                 rcu_assign_pointer(device->name, name);
 431                 INIT_LIST_HEAD(&device->dev_alloc_list);
 432
 433                 /* init readahead state */
 434                 spin_lock_init(&device->reada_lock);
 435                 device->reada_curr_zone = NULL;
 436                 atomic_set(&device->reada_in_flight, 0);
 437                 device->reada_next = 0;
 438                 INIT_RADIX_TREE(&device->reada_zones, GFP_NOFS & ~__GFP_WAIT);
 439                 INIT_RADIX_TREE(&device->reada_extents, GFP_NOFS & ~__GFP_WAIT);
 440
 441                 mutex_lock(&fs_devices->device_list_mutex);
 442                 list_add_rcu(&device->dev_list, &fs_devices->devices);
 443                 mutex_unlock(&fs_devices->device_list_mutex);
 444
 445                 device->fs_devices = fs_devices;
 446                 fs_devices->num_devices++;
 447         } else if (!device->name || strcmp(device->name->str, path)) {
 448                 name = rcu_string_strdup(path, GFP_NOFS);
 449                 if (!name)
 450                         return -ENOMEM;
 451                 rcu_string_free(device->name);
 452                 rcu_assign_pointer(device->name, name);
 453                 if (device->missing) {
 454                         fs_devices->missing_devices--;
 455                         device->missing = 0;
 456                 }
 457         }
 458
 459         if (found_transid > fs_devices->latest_trans) {
 460                 fs_devices->latest_devid = devid;
 461                 fs_devices->latest_trans = found_transid;
 462         }
 463         *fs_devices_ret = fs_devices;
 464         return 0;
 465 }
 466
 467 static struct btrfs_fs_devices *clone_fs_devices(struct btrfs_fs_devices *orig)
 468 {
 469         struct btrfs_fs_devices *fs_devices;
 470         struct btrfs_device *device;
 471         struct btrfs_device *orig_dev;
 472
 473         fs_devices = kzalloc(sizeof(*fs_devices), GFP_NOFS);
 474         if (!fs_devices)
 475                 return ERR_PTR(-ENOMEM);
 476
 477         INIT_LIST_HEAD(&fs_devices->devices);
 478         INIT_LIST_HEAD(&fs_devices->alloc_list);
 479         INIT_LIST_HEAD(&fs_devices->list);
 480         mutex_init(&fs_devices->device_list_mutex);
 481         fs_devices->latest_devid = orig->latest_devid;
 482         fs_devices->latest_trans = orig->latest_trans;
 483         fs_devices->total_devices = orig->total_devices;
 484         memcpy(fs_devices->fsid, orig->fsid, sizeof(fs_devices->fsid));
 485
 486         /* We have held the volume lock, it is safe to get the devices. */
 487         list_for_each_entry(orig_dev, &orig->devices, dev_list) {
 488                 struct rcu_string *name;
 489
 490                 device = kzalloc(sizeof(*device), GFP_NOFS);
 491                 if (!device)
 492                         goto error;
 493
 494                 /*
 495                  * This is ok to do without rcu read locked because we hold the
 496                  * uuid mutex so nothing we touch in here is going to disappear.
 497                  */
 498                 name = rcu_string_strdup(orig_dev->name->str, GFP_NOFS);
 499                 if (!name) {
 500                         kfree(device);
 501                         goto error;
 502                 }
 503                 rcu_assign_pointer(device->name, name);
 504
 505                 device->devid = orig_dev->devid;
 506                 device->work.func = pending_bios_fn;
 507                 memcpy(device->uuid, orig_dev->uuid, sizeof(device->uuid));
 508                 spin_lock_init(&device->io_lock);
 509                 INIT_LIST_HEAD(&device->dev_list);
 510                 INIT_LIST_HEAD(&device->dev_alloc_list);
 511
 512                 list_add(&device->dev_list, &fs_devices->devices);
 513                 device->fs_devices = fs_devices;
 514                 fs_devices->num_devices++;
 515         }
 516         return fs_devices;
 517 error:
 518         free_fs_devices(fs_devices);
 519         return ERR_PTR(-ENOMEM);
 520 }
 521
 522 void btrfs_close_extra_devices(struct btrfs_fs_info *fs_info,
 523                                struct btrfs_fs_devices *fs_devices, int step)
 524 {
 525         struct btrfs_device *device, *next;
 526
 527         struct block_device *latest_bdev = NULL;
 528         u64 latest_devid = 0;
 529         u64 latest_transid = 0;
 530
 531         mutex_lock(&uuid_mutex);
 532 again:
 533         /* This is the initialized path, it is safe to release the devices. */
 534         list_for_each_entry_safe(device, next, &fs_devices->devices, dev_list) {
 535                 if (device->in_fs_metadata) {
 536                         if (!device->is_tgtdev_for_dev_replace &&
 537                             (!latest_transid ||
 538                              device->generation > latest_transid)) {
 539                                 latest_devid = device->devid;
 540                                 latest_transid = device->generation;
 541                                 latest_bdev = device->bdev;
 542                         }
 543                         continue;
 544                 }
 545
 546                 if (device->devid == BTRFS_DEV_REPLACE_DEVID) {
 547                         /*
 548                          * In the first step, keep the device which has
 549                          * the correct fsid and the devid that is used
 550                          * for the dev_replace procedure.
 551                          * In the second step, the dev_replace state is
 552                          * read from the device tree and it is known
 553                          * whether the procedure is really active or
 554                          * not, which means whether this device is
 555                          * used or whether it should be removed.
 556                          */
 557                         if (step == 0 || device->is_tgtdev_for_dev_replace) {
 558                                 continue;
 559                         }
 560                 }
 561                 if (device->bdev) {
 562                         blkdev_put(device->bdev, device->mode);
 563                         device->bdev = NULL;
 564                         fs_devices->open_devices--;
 565                 }
 566                 if (device->writeable) {
 567                         list_del_init(&device->dev_alloc_list);
 568                         device->writeable = 0;
 569                         if (!device->is_tgtdev_for_dev_replace)
 570                                 fs_devices->rw_devices--;
 571                 }
 572                 list_del_init(&device->dev_list);
 573                 fs_devices->num_devices--;
 574                 rcu_string_free(device->name);
 575                 kfree(device);
 576         }
 577
 578         if (fs_devices->seed) {
 579                 fs_devices = fs_devices->seed;
 580                 goto again;
 581         }
 582
 583         fs_devices->latest_bdev = latest_bdev;
 584         fs_devices->latest_devid = latest_devid;
 585         fs_devices->latest_trans = latest_transid;
 586
 587         mutex_unlock(&uuid_mutex);
 588 }
 589
 590 static void __free_device(struct work_struct *work)
 591 {
 592         struct btrfs_device *device;
 593
 594         device = container_of(work, struct btrfs_device, rcu_work);
 595
 596         if (device->bdev)
 597                 blkdev_put(device->bdev, device->mode);
 598
 599         rcu_string_free(device->name);
 600         kfree(device);
 601 }
 602
 603 static void free_device(struct rcu_head *head)
 604 {
 605         struct btrfs_device *device;
 606
 607         device = container_of(head, struct btrfs_device, rcu);
 608
 609         INIT_WORK(&device->rcu_work, __free_device);
 610         schedule_work(&device->rcu_work);
 611 }
 612
 613 static int __btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
 614 {
 615         struct btrfs_device *device;
 616
 617         if (--fs_devices->opened > 0)
 618                 return 0;
 619
 620         mutex_lock(&fs_devices->device_list_mutex);
 621         list_for_each_entry(device, &fs_devices->devices, dev_list) {
 622                 struct btrfs_device *new_device;
 623                 struct rcu_string *name;
 624
 625                 if (device->bdev)
 626                         fs_devices->open_devices--;
 627
 628                 if (device->writeable && !device->is_tgtdev_for_dev_replace) {
 629                         list_del_init(&device->dev_alloc_list);
 630                         fs_devices->rw_devices--;
 631                 }
 632
 633                 if (device->can_discard)
 634                         fs_devices->num_can_discard--;
 635
 636                 new_device = kmalloc(sizeof(*new_device), GFP_NOFS);
 637                 BUG_ON(!new_device); /* -ENOMEM */
 638                 memcpy(new_device, device, sizeof(*new_device));
 639
 640                 /* Safe because we are under uuid_mutex */
 641                 if (device->name) {
 642                         name = rcu_string_strdup(device->name->str, GFP_NOFS);
 643                         BUG_ON(device->name && !name); /* -ENOMEM */
 644                         rcu_assign_pointer(new_device->name, name);
 645                 }
 646                 new_device->bdev = NULL;
 647                 new_device->writeable = 0;
 648                 new_device->in_fs_metadata = 0;
 649                 new_device->can_discard = 0;
 650                 list_replace_rcu(&device->dev_list, &new_device->dev_list);
 651
 652                 call_rcu(&device->rcu, free_device);
 653         }
 654         mutex_unlock(&fs_devices->device_list_mutex);
 655
 656         WARN_ON(fs_devices->open_devices);
 657         WARN_ON(fs_devices->rw_devices);
 658         fs_devices->opened = 0;
 659         fs_devices->seeding = 0;
 660
 661         return 0;
 662 }
 663
 664 int btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
 665 {
 666         struct btrfs_fs_devices *seed_devices = NULL;
 667         int ret;
 668
 669         mutex_lock(&uuid_mutex);
 670         ret = __btrfs_close_devices(fs_devices);
 671         if (!fs_devices->opened) {
 672                 seed_devices = fs_devices->seed;
 673                 fs_devices->seed = NULL;
 674         }
 675         mutex_unlock(&uuid_mutex);
 676
 677         while (seed_devices) {
 678                 fs_devices = seed_devices;
 679                 seed_devices = fs_devices->seed;
 680                 __btrfs_close_devices(fs_devices);
 681                 free_fs_devices(fs_devices);
 682         }
 683         return ret;
 684 }
 685
 686 static int __btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
 687                                 fmode_t flags, void *holder)
 688 {
 689         struct request_queue *q;
 690         struct block_device *bdev;
 691         struct list_head *head = &fs_devices->devices;
 692         struct btrfs_device *device;
 693         struct block_device *latest_bdev = NULL;
 694         struct buffer_head *bh;
 695         struct btrfs_super_block *disk_super;
 696         u64 latest_devid = 0;
 697         u64 latest_transid = 0;
 698         u64 devid;
 699         int seeding = 1;
 700         int ret = 0;
 701
 702         flags |= FMODE_EXCL;
 703
 704         list_for_each_entry(device, head, dev_list) {
 705                 if (device->bdev)
 706                         continue;
 707                 if (!device->name)
 708                         continue;
 709
 710                 ret = btrfs_get_bdev_and_sb(device->name->str, flags, holder, 1,
 711                                             &bdev, &bh);
 712                 if (ret)
 713                         continue;
 714
 715                 disk_super = (struct btrfs_super_block *)bh->b_data;
 716                 devid = btrfs_stack_device_id(&disk_super->dev_item);
 717                 if (devid != device->devid)
 718                         goto error_brelse;
 719
 720                 if (memcmp(device->uuid, disk_super->dev_item.uuid,
 721                            BTRFS_UUID_SIZE))
 722                         goto error_brelse;
 723
 724                 device->generation = btrfs_super_generation(disk_super);
 725                 if (!latest_transid || device->generation > latest_transid) {
 726                         latest_devid = devid;
 727                         latest_transid = device->generation;
 728                         latest_bdev = bdev;
 729                 }
 730
 731                 if (btrfs_super_flags(disk_super) & BTRFS_SUPER_FLAG_SEEDING) {
 732                         device->writeable = 0;
 733                 } else {
 734                         device->writeable = !bdev_read_only(bdev);
 735                         seeding = 0;
 736                 }
 737
 738                 q = bdev_get_queue(bdev);
 739                 if (blk_queue_discard(q)) {
 740                         device->can_discard = 1;
 741                         fs_devices->num_can_discard++;
 742                 }
 743
 744                 device->bdev = bdev;
 745                 device->in_fs_metadata = 0;
 746                 device->mode = flags;
 747
 748                 if (!blk_queue_nonrot(bdev_get_queue(bdev)))
 749                         fs_devices->rotating = 1;
 750
 751                 fs_devices->open_devices++;
 752                 if (device->writeable && !device->is_tgtdev_for_dev_replace) {
 753                         fs_devices->rw_devices++;
 754                         list_add(&device->dev_alloc_list,
 755                                  &fs_devices->alloc_list);
 756                 }
 757                 brelse(bh);
 758                 continue;
 759
 760 error_brelse:
 761                 brelse(bh);
 762                 blkdev_put(bdev, flags);
 763                 continue;
 764         }
 765         if (fs_devices->open_devices == 0) {
 766                 ret = -EINVAL;
 767                 goto out;
 768         }
 769         fs_devices->seeding = seeding;
 770         fs_devices->opened = 1;
 771         fs_devices->latest_bdev = latest_bdev;
 772         fs_devices->latest_devid = latest_devid;
 773         fs_devices->latest_trans = latest_transid;
 774         fs_devices->total_rw_bytes = 0;
 775 out:
 776         return ret;
 777 }
 778
 779 int btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
 780                        fmode_t flags, void *holder)
 781 {
 782         int ret;
 783
 784         mutex_lock(&uuid_mutex);
 785         if (fs_devices->opened) {
 786                 fs_devices->opened++;
 787                 ret = 0;
 788         } else {
 789                 ret = __btrfs_open_devices(fs_devices, flags, holder);
 790         }
 791         mutex_unlock(&uuid_mutex);
 792         return ret;
 793 }
 794
 795 int btrfs_scan_one_device(const char *path, fmode_t flags, void *holder,
 796                           struct btrfs_fs_devices **fs_devices_ret)
 797 {
 798         struct btrfs_super_block *disk_super;
 799         struct block_device *bdev;
 800         struct buffer_head *bh;
 801         int ret;
 802         u64 devid;
 803         u64 transid;
 804         u64 total_devices;
 805
 806         flags |= FMODE_EXCL;
 807         mutex_lock(&uuid_mutex);
 808         ret = btrfs_get_bdev_and_sb(path, flags, holder, 0, &bdev, &bh);
 809         if (ret)
 810                 goto error;
 811         disk_super = (struct btrfs_super_block *)bh->b_data;
 812         devid = btrfs_stack_device_id(&disk_super->dev_item);
 813         transid = btrfs_super_generation(disk_super);
 814         total_devices = btrfs_super_num_devices(disk_super);
 815         if (disk_super->label[0]) {
 816                 if (disk_super->label[BTRFS_LABEL_SIZE - 1])
 817                         disk_super->label[BTRFS_LABEL_SIZE - 1] = '\0';
 818                 printk(KERN_INFO "device label %s ", disk_super->label);
 819         } else {
 820                 printk(KERN_INFO "device fsid %pU ", disk_super->fsid);
 821         }
 822         printk(KERN_CONT "devid %llu transid %llu %s\n",
 823                (unsigned long long)devid, (unsigned long long)transid, path);
 824         ret = device_list_add(path, disk_super, devid, fs_devices_ret);
 825         if (!ret && fs_devices_ret)
 826                 (*fs_devices_ret)->total_devices = total_devices;
 827         brelse(bh);
 828         blkdev_put(bdev, flags);
 829 error:
 830         mutex_unlock(&uuid_mutex);
 831         return ret;
 832 }
 833
 834 /* helper to account the used device space in the range */
 835 int btrfs_account_dev_extents_size(struct btrfs_device *device, u64 start,
 836                                    u64 end, u64 *length)
 837 {
 838         struct btrfs_key key;
 839         struct btrfs_root *root = device->dev_root;
 840         struct btrfs_dev_extent *dev_extent;
 841         struct btrfs_path *path;
 842         u64 extent_end;
 843         int ret;
 844         int slot;
 845         struct extent_buffer *l;
 846
 847         *length = 0;
 848
 849         if (start >= device->total_bytes || device->is_tgtdev_for_dev_replace)
 850                 return 0;
 851
 852         path = btrfs_alloc_path();
 853         if (!path)
 854                 return -ENOMEM;
 855         path->reada = 2;
 856
 857         key.objectid = device->devid;
 858         key.offset = start;
 859         key.type = BTRFS_DEV_EXTENT_KEY;
 860
 861         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 862         if (ret < 0)
 863                 goto out;
 864         if (ret > 0) {
 865                 ret = btrfs_previous_item(root, path, key.objectid, key.type);
 866                 if (ret < 0)
 867                         goto out;
 868         }
 869
 870         while (1) {
 871                 l = path->nodes[0];
 872                 slot = path->slots[0];
 873                 if (slot >= btrfs_header_nritems(l)) {
 874                         ret = btrfs_next_leaf(root, path);
 875                         if (ret == 0)
 876                                 continue;
 877                         if (ret < 0)
 878                                 goto out;
 879
 880                         break;
 881                 }
 882                 btrfs_item_key_to_cpu(l, &key, slot);
 883
 884                 if (key.objectid < device->devid)
 885                         goto next;
 886
 887                 if (key.objectid > device->devid)
 888                         break;
 889
 890                 if (btrfs_key_type(&key) != BTRFS_DEV_EXTENT_KEY)
 891                         goto next;
 892
 893                 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
 894                 extent_end = key.offset + btrfs_dev_extent_length(l,
 895                                                                   dev_extent);
 896                 if (key.offset <= start && extent_end > end) {
 897                         *length = end - start + 1;
 898                         break;
 899                 } else if (key.offset <= start && extent_end > start)
 900                         *length += extent_end - start;
 901                 else if (key.offset > start && extent_end <= end)
 902                         *length += extent_end - key.offset;
 903                 else if (key.offset > start && key.offset <= end) {
 904                         *length += end - key.offset + 1;
 905                         break;
 906                 } else if (key.offset > end)
 907                         break;
 908
 909 next:
 910                 path->slots[0]++;
 911         }
 912         ret = 0;
 913 out:
 914         btrfs_free_path(path);
 915         return ret;
 916 }
 917
 918 /*
 919  * find_free_dev_extent - find free space in the specified device
 920  * @device:     the device which we search the free space in
 921  * @num_bytes:  the size of the free space that we need
 922  * @start:      store the start of the free space.
 923  * @len:        the size of the free space. that we find, or the size of the max
 924  *              free space if we don't find suitable free space
 925  *
 926  * this uses a pretty simple search, the expectation is that it is
 927  * called very infrequently and that a given device has a small number
 928  * of extents
 929  *
 930  * @start is used to store the start of the free space if we find. But if we
 931  * don't find suitable free space, it will be used to store the start position
 932  * of the max free space.
 933  *
 934  * @len is used to store the size of the free space that we find.
 935  * But if we don't find suitable free space, it is used to store the size of
 936  * the max free space.
 937  */
 938 int find_free_dev_extent(struct btrfs_device *device, u64 num_bytes,
 939                          u64 *start, u64 *len)
 940 {
 941         struct btrfs_key key;
 942         struct btrfs_root *root = device->dev_root;
 943         struct btrfs_dev_extent *dev_extent;
 944         struct btrfs_path *path;
 945         u64 hole_size;
 946         u64 max_hole_start;
 947         u64 max_hole_size;
 948         u64 extent_end;
 949         u64 search_start;
 950         u64 search_end = device->total_bytes;
 951         int ret;
 952         int slot;
 953         struct extent_buffer *l;
 954
 955         /* FIXME use last free of some kind */
 956
 957         /* we don't want to overwrite the superblock on the drive,
 958          * so we make sure to start at an offset of at least 1MB
 959          */
 960         search_start = max(root->fs_info->alloc_start, 1024ull * 1024);
 961
 962         max_hole_start = search_start;
 963         max_hole_size = 0;
 964         hole_size = 0;
 965
 966         if (search_start >= search_end || device->is_tgtdev_for_dev_replace) {
 967                 ret = -ENOSPC;
 968                 goto error;
 969         }
 970
 971         path = btrfs_alloc_path();
 972         if (!path) {
 973                 ret = -ENOMEM;
 974                 goto error;
 975         }
 976         path->reada = 2;
 977
 978         key.objectid = device->devid;
 979         key.offset = search_start;
 980         key.type = BTRFS_DEV_EXTENT_KEY;
 981
 982         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 983         if (ret < 0)
 984                 goto out;
 985         if (ret > 0) {
 986                 ret = btrfs_previous_item(root, path, key.objectid, key.type);
 987                 if (ret < 0)
 988                         goto out;
 989         }
 990
 991         while (1) {
 992                 l = path->nodes[0];
 993                 slot = path->slots[0];
 994                 if (slot >= btrfs_header_nritems(l)) {
 995                         ret = btrfs_next_leaf(root, path);
 996                         if (ret == 0)
 997                                 continue;
 998                         if (ret < 0)
 999                                 goto out;
1000
1001                         break;
1002                 }
1003                 btrfs_item_key_to_cpu(l, &key, slot);
1004
1005                 if (key.objectid < device->devid)
1006                         goto next;
1007
1008                 if (key.objectid > device->devid)
1009                         break;
1010
1011                 if (btrfs_key_type(&key) != BTRFS_DEV_EXTENT_KEY)
1012                         goto next;
1013
1014                 if (key.offset > search_start) {
1015                         hole_size = key.offset - search_start;
1016
1017                         if (hole_size > max_hole_size) {
1018                                 max_hole_start = search_start;
1019                                 max_hole_size = hole_size;
1020                         }
1021
1022                         /*
1023                          * If this free space is greater than which we need,
1024                          * it must be the max free space that we have found
1025                          * until now, so max_hole_start must point to the start
1026                          * of this free space and the length of this free space
1027                          * is stored in max_hole_size. Thus, we return
1028                          * max_hole_start and max_hole_size and go back to the
1029                          * caller.
1030                          */
1031                         if (hole_size >= num_bytes) {
1032                                 ret = 0;
1033                                 goto out;
1034                         }
1035                 }
1036
1037                 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
1038                 extent_end = key.offset + btrfs_dev_extent_length(l,
1039                                                                   dev_extent);
1040                 if (extent_end > search_start)
1041                         search_start = extent_end;
1042 next:
1043                 path->slots[0]++;
1044                 cond_resched();
1045         }
1046
1047         /*
1048          * At this point, search_start should be the end of
1049          * allocated dev extents, and when shrinking the device,
1050          * search_end may be smaller than search_start.
1051          */
1052         if (search_end > search_start)
1053                 hole_size = search_end - search_start;
1054
1055         if (hole_size > max_hole_size) {
1056                 max_hole_start = search_start;
1057                 max_hole_size = hole_size;
1058         }
1059
1060         /* See above. */
1061         if (hole_size < num_bytes)
1062                 ret = -ENOSPC;
1063         else
1064                 ret = 0;
1065
1066 out:
1067         btrfs_free_path(path);
1068 error:
1069         *start = max_hole_start;
1070         if (len)
1071                 *len = max_hole_size;
1072         return ret;
1073 }
1074
1075 static int btrfs_free_dev_extent(struct btrfs_trans_handle *trans,
1076                           struct btrfs_device *device,
1077                           u64 start)
1078 {
1079         int ret;
1080         struct btrfs_path *path;
1081         struct btrfs_root *root = device->dev_root;
1082         struct btrfs_key key;
1083         struct btrfs_key found_key;
1084         struct extent_buffer *leaf = NULL;
1085         struct btrfs_dev_extent *extent = NULL;
1086
1087         path = btrfs_alloc_path();
1088         if (!path)
1089                 return -ENOMEM;
1090
1091         key.objectid = device->devid;
1092         key.offset = start;
1093         key.type = BTRFS_DEV_EXTENT_KEY;
1094 again:
1095         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1096         if (ret > 0) {
1097                 ret = btrfs_previous_item(root, path, key.objectid,
1098                                           BTRFS_DEV_EXTENT_KEY);
1099                 if (ret)
1100                         goto out;
1101                 leaf = path->nodes[0];
1102                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1103                 extent = btrfs_item_ptr(leaf, path->slots[0],
1104                                         struct btrfs_dev_extent);
1105                 BUG_ON(found_key.offset > start || found_key.offset +
1106                        btrfs_dev_extent_length(leaf, extent) < start);
1107                 key = found_key;
1108                 btrfs_release_path(path);
1109                 goto again;
1110         } else if (ret == 0) {
1111                 leaf = path->nodes[0];
1112                 extent = btrfs_item_ptr(leaf, path->slots[0],
1113                                         struct btrfs_dev_extent);
1114         } else {
1115                 btrfs_error(root->fs_info, ret, "Slot search failed");
1116                 goto out;
1117         }
1118
1119         if (device->bytes_used > 0) {
1120                 u64 len = btrfs_dev_extent_length(leaf, extent);
1121                 device->bytes_used -= len;
1122                 spin_lock(&root->fs_info->free_chunk_lock);
1123                 root->fs_info->free_chunk_space += len;
1124                 spin_unlock(&root->fs_info->free_chunk_lock);
1125         }
1126         ret = btrfs_del_item(trans, root, path);
1127         if (ret) {
1128                 btrfs_error(root->fs_info, ret,
1129                             "Failed to remove dev extent item");
1130         }
1131 out:
1132         btrfs_free_path(path);
1133         return ret;
1134 }
1135
1136 int btrfs_alloc_dev_extent(struct btrfs_trans_handle *trans,
1137                            struct btrfs_device *device,
1138                            u64 chunk_tree, u64 chunk_objectid,
1139                            u64 chunk_offset, u64 start, u64 num_bytes)
1140 {
1141         int ret;
1142         struct btrfs_path *path;
1143         struct btrfs_root *root = device->dev_root;
1144         struct btrfs_dev_extent *extent;
1145         struct extent_buffer *leaf;
1146         struct btrfs_key key;
1147
1148         WARN_ON(!device->in_fs_metadata);
1149         WARN_ON(device->is_tgtdev_for_dev_replace);
1150         path = btrfs_alloc_path();
1151         if (!path)
1152                 return -ENOMEM;
1153
1154         key.objectid = device->devid;
1155         key.offset = start;
1156         key.type = BTRFS_DEV_EXTENT_KEY;
1157         ret = btrfs_insert_empty_item(trans, root, path, &key,
1158                                       sizeof(*extent));
1159         if (ret)
1160                 goto out;
1161
1162         leaf = path->nodes[0];
1163         extent = btrfs_item_ptr(leaf, path->slots[0],
1164                                 struct btrfs_dev_extent);
1165         btrfs_set_dev_extent_chunk_tree(leaf, extent, chunk_tree);
1166         btrfs_set_dev_extent_chunk_objectid(leaf, extent, chunk_objectid);
1167         btrfs_set_dev_extent_chunk_offset(leaf, extent, chunk_offset);
1168
1169         write_extent_buffer(leaf, root->fs_info->chunk_tree_uuid,
1170                     (unsigned long)btrfs_dev_extent_chunk_tree_uuid(extent),
1171                     BTRFS_UUID_SIZE);
1172
1173         btrfs_set_dev_extent_length(leaf, extent, num_bytes);
1174         btrfs_mark_buffer_dirty(leaf);
1175 out:
1176         btrfs_free_path(path);
1177         return ret;
1178 }
1179
1180 static noinline int find_next_chunk(struct btrfs_root *root,
1181                                     u64 objectid, u64 *offset)
1182 {
1183         struct btrfs_path *path;
1184         int ret;
1185         struct btrfs_key key;
1186         struct btrfs_chunk *chunk;
1187         struct btrfs_key found_key;
1188
1189         path = btrfs_alloc_path();
1190         if (!path)
1191                 return -ENOMEM;
1192
1193         key.objectid = objectid;
1194         key.offset = (u64)-1;
1195         key.type = BTRFS_CHUNK_ITEM_KEY;
1196
1197         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1198         if (ret < 0)
1199                 goto error;
1200
1201         BUG_ON(ret == 0); /* Corruption */
1202
1203         ret = btrfs_previous_item(root, path, 0, BTRFS_CHUNK_ITEM_KEY);
1204         if (ret) {
1205                 *offset = 0;
1206         } else {
1207                 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
1208                                       path->slots[0]);
1209                 if (found_key.objectid != objectid)
1210                         *offset = 0;
1211                 else {
1212                         chunk = btrfs_item_ptr(path->nodes[0], path->slots[0],
1213                                                struct btrfs_chunk);
1214                         *offset = found_key.offset +
1215                                 btrfs_chunk_length(path->nodes[0], chunk);
1216                 }
1217         }
1218         ret = 0;
1219 error:
1220         btrfs_free_path(path);
1221         return ret;
1222 }
1223
1224 static noinline int find_next_devid(struct btrfs_root *root, u64 *objectid)
1225 {
1226         int ret;
1227         struct btrfs_key key;
1228         struct btrfs_key found_key;
1229         struct btrfs_path *path;
1230
1231         root = root->fs_info->chunk_root;
1232
1233         path = btrfs_alloc_path();
1234         if (!path)
1235                 return -ENOMEM;
1236
1237         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1238         key.type = BTRFS_DEV_ITEM_KEY;
1239         key.offset = (u64)-1;
1240
1241         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1242         if (ret < 0)
1243                 goto error;
1244
1245         BUG_ON(ret == 0); /* Corruption */
1246
1247         ret = btrfs_previous_item(root, path, BTRFS_DEV_ITEMS_OBJECTID,
1248                                   BTRFS_DEV_ITEM_KEY);
1249         if (ret) {
1250                 *objectid = 1;
1251         } else {
1252                 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
1253                                       path->slots[0]);
1254                 *objectid = found_key.offset + 1;
1255         }
1256         ret = 0;
1257 error:
1258         btrfs_free_path(path);
1259         return ret;
1260 }
1261
1262 /*
1263  * the device information is stored in the chunk root
1264  * the btrfs_device struct should be fully filled in
1265  */
1266 int btrfs_add_device(struct btrfs_trans_handle *trans,
1267                      struct btrfs_root *root,
1268                      struct btrfs_device *device)
1269 {
1270         int ret;
1271         struct btrfs_path *path;
1272         struct btrfs_dev_item *dev_item;
1273         struct extent_buffer *leaf;
1274         struct btrfs_key key;
1275         unsigned long ptr;
1276
1277         root = root->fs_info->chunk_root;
1278
1279         path = btrfs_alloc_path();
1280         if (!path)
1281                 return -ENOMEM;
1282
1283         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1284         key.type = BTRFS_DEV_ITEM_KEY;
1285         key.offset = device->devid;
1286
1287         ret = btrfs_insert_empty_item(trans, root, path, &key,
1288                                       sizeof(*dev_item));
1289         if (ret)
1290                 goto out;
1291
1292         leaf = path->nodes[0];
1293         dev_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dev_item);
1294
1295         btrfs_set_device_id(leaf, dev_item, device->devid);
1296         btrfs_set_device_generation(leaf, dev_item, 0);
1297         btrfs_set_device_type(leaf, dev_item, device->type);
1298         btrfs_set_device_io_align(leaf, dev_item, device->io_align);
1299         btrfs_set_device_io_width(leaf, dev_item, device->io_width);
1300         btrfs_set_device_sector_size(leaf, dev_item, device->sector_size);
1301         btrfs_set_device_total_bytes(leaf, dev_item, device->total_bytes);
1302         btrfs_set_device_bytes_used(leaf, dev_item, device->bytes_used);
1303         btrfs_set_device_group(leaf, dev_item, 0);
1304         btrfs_set_device_seek_speed(leaf, dev_item, 0);
1305         btrfs_set_device_bandwidth(leaf, dev_item, 0);
1306         btrfs_set_device_start_offset(leaf, dev_item, 0);
1307
1308         ptr = (unsigned long)btrfs_device_uuid(dev_item);
1309         write_extent_buffer(leaf, device->uuid, ptr, BTRFS_UUID_SIZE);
1310         ptr = (unsigned long)btrfs_device_fsid(dev_item);
1311         write_extent_buffer(leaf, root->fs_info->fsid, ptr, BTRFS_UUID_SIZE);
1312         btrfs_mark_buffer_dirty(leaf);
1313
1314         ret = 0;
1315 out:
1316         btrfs_free_path(path);
1317         return ret;
1318 }
1319
1320 static int btrfs_rm_dev_item(struct btrfs_root *root,
1321                              struct btrfs_device *device)
1322 {
1323         int ret;
1324         struct btrfs_path *path;
1325         struct btrfs_key key;
1326         struct btrfs_trans_handle *trans;
1327
1328         root = root->fs_info->chunk_root;
1329
1330         path = btrfs_alloc_path();
1331         if (!path)
1332                 return -ENOMEM;
1333
1334         trans = btrfs_start_transaction(root, 0);
1335         if (IS_ERR(trans)) {
1336                 btrfs_free_path(path);
1337                 return PTR_ERR(trans);
1338         }
1339         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1340         key.type = BTRFS_DEV_ITEM_KEY;
1341         key.offset = device->devid;
1342         lock_chunks(root);
1343
1344         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1345         if (ret < 0)
1346                 goto out;
1347
1348         if (ret > 0) {
1349                 ret = -ENOENT;
1350                 goto out;
1351         }
1352
1353         ret = btrfs_del_item(trans, root, path);
1354         if (ret)
1355                 goto out;
1356 out:
1357         btrfs_free_path(path);
1358         unlock_chunks(root);
1359         btrfs_commit_transaction(trans, root);
1360         return ret;
1361 }
1362
1363 int btrfs_rm_device(struct btrfs_root *root, char *device_path)
1364 {
1365         struct btrfs_device *device;
1366         struct btrfs_device *next_device;
1367         struct block_device *bdev;
1368         struct buffer_head *bh = NULL;
1369         struct btrfs_super_block *disk_super;
1370         struct btrfs_fs_devices *cur_devices;
1371         u64 all_avail;
1372         u64 devid;
1373         u64 num_devices;
1374         u8 *dev_uuid;
1375         int ret = 0;
1376         bool clear_super = false;
1377
1378         mutex_lock(&uuid_mutex);
1379
1380         all_avail = root->fs_info->avail_data_alloc_bits |
1381                 root->fs_info->avail_system_alloc_bits |
1382                 root->fs_info->avail_metadata_alloc_bits;
1383
1384         num_devices = root->fs_info->fs_devices->num_devices;
1385         btrfs_dev_replace_lock(&root->fs_info->dev_replace);
1386         if (btrfs_dev_replace_is_ongoing(&root->fs_info->dev_replace)) {
1387                 WARN_ON(num_devices < 1);
1388                 num_devices--;
1389         }
1390         btrfs_dev_replace_unlock(&root->fs_info->dev_replace);
1391
1392         if ((all_avail & BTRFS_BLOCK_GROUP_RAID10) && num_devices <= 4) {
1393                 printk(KERN_ERR "btrfs: unable to go below four devices "
1394                        "on raid10\n");
1395                 ret = -EINVAL;
1396                 goto out;
1397         }
1398
1399         if ((all_avail & BTRFS_BLOCK_GROUP_RAID1) && num_devices <= 2) {
1400                 printk(KERN_ERR "btrfs: unable to go below two "
1401                        "devices on raid1\n");
1402                 ret = -EINVAL;
1403                 goto out;
1404         }
1405
1406         if (strcmp(device_path, "missing") == 0) {
1407                 struct list_head *devices;
1408                 struct btrfs_device *tmp;
1409
1410                 device = NULL;
1411                 devices = &root->fs_info->fs_devices->devices;
1412                 /*
1413                  * It is safe to read the devices since the volume_mutex
1414                  * is held.
1415                  */
1416                 list_for_each_entry(tmp, devices, dev_list) {
1417                         if (tmp->in_fs_metadata &&
1418                             !tmp->is_tgtdev_for_dev_replace &&
1419                             !tmp->bdev) {
1420                                 device = tmp;
1421                                 break;
1422                         }
1423                 }
1424                 bdev = NULL;
1425                 bh = NULL;
1426                 disk_super = NULL;
1427                 if (!device) {
1428                         printk(KERN_ERR "btrfs: no missing devices found to "
1429                                "remove\n");
1430                         goto out;
1431                 }
1432         } else {
1433                 ret = btrfs_get_bdev_and_sb(device_path,
1434                                             FMODE_READ | FMODE_EXCL,
1435                                             root->fs_info->bdev_holder, 0,
1436                                             &bdev, &bh);
1437                 if (ret)
1438                         goto out;
1439                 disk_super = (struct btrfs_super_block *)bh->b_data;
1440                 devid = btrfs_stack_device_id(&disk_super->dev_item);
1441                 dev_uuid = disk_super->dev_item.uuid;
1442                 device = btrfs_find_device(root->fs_info, devid, dev_uuid,
1443                                            disk_super->fsid);
1444                 if (!device) {
1445                         ret = -ENOENT;
1446                         goto error_brelse;
1447                 }
1448         }
1449
1450         if (device->is_tgtdev_for_dev_replace) {
1451                 pr_err("btrfs: unable to remove the dev_replace target dev\n");
1452                 ret = -EINVAL;
1453                 goto error_brelse;
1454         }
1455
1456         if (device->writeable && root->fs_info->fs_devices->rw_devices == 1) {
1457                 printk(KERN_ERR "btrfs: unable to remove the only writeable "
1458                        "device\n");
1459                 ret = -EINVAL;
1460                 goto error_brelse;
1461         }
1462
1463         if (device->writeable) {
1464                 lock_chunks(root);
1465                 list_del_init(&device->dev_alloc_list);
1466                 unlock_chunks(root);
1467                 root->fs_info->fs_devices->rw_devices--;
1468                 clear_super = true;
1469         }
1470
1471         ret = btrfs_shrink_device(device, 0);
1472         if (ret)
1473                 goto error_undo;
1474
1475         /*
1476          * TODO: the superblock still includes this device in its num_devices
1477          * counter although write_all_supers() is not locked out. This
1478          * could give a filesystem state which requires a degraded mount.
1479          */
1480         ret = btrfs_rm_dev_item(root->fs_info->chunk_root, device);
1481         if (ret)
1482                 goto error_undo;
1483
1484         spin_lock(&root->fs_info->free_chunk_lock);
1485         root->fs_info->free_chunk_space = device->total_bytes -
1486                 device->bytes_used;
1487         spin_unlock(&root->fs_info->free_chunk_lock);
1488
1489         device->in_fs_metadata = 0;
1490         btrfs_scrub_cancel_dev(root->fs_info, device);
1491
1492         /*
1493          * the device list mutex makes sure that we don't change
1494          * the device list while someone else is writing out all
1495          * the device supers.
1496          */
1497
1498         cur_devices = device->fs_devices;
1499         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
1500         list_del_rcu(&device->dev_list);
1501
1502         device->fs_devices->num_devices--;
1503         device->fs_devices->total_devices--;
1504
1505         if (device->missing)
1506                 root->fs_info->fs_devices->missing_devices--;
1507
1508         next_device = list_entry(root->fs_info->fs_devices->devices.next,
1509                                  struct btrfs_device, dev_list);
1510         if (device->bdev == root->fs_info->sb->s_bdev)
1511                 root->fs_info->sb->s_bdev = next_device->bdev;
1512         if (device->bdev == root->fs_info->fs_devices->latest_bdev)
1513                 root->fs_info->fs_devices->latest_bdev = next_device->bdev;
1514
1515         if (device->bdev)
1516                 device->fs_devices->open_devices--;
1517
1518         call_rcu(&device->rcu, free_device);
1519         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1520
1521         num_devices = btrfs_super_num_devices(root->fs_info->super_copy) - 1;
1522         btrfs_set_super_num_devices(root->fs_info->super_copy, num_devices);
1523
1524         if (cur_devices->open_devices == 0) {
1525                 struct btrfs_fs_devices *fs_devices;
1526                 fs_devices = root->fs_info->fs_devices;
1527                 while (fs_devices) {
1528                         if (fs_devices->seed == cur_devices)
1529                                 break;
1530                         fs_devices = fs_devices->seed;
1531                 }
1532                 fs_devices->seed = cur_devices->seed;
1533                 cur_devices->seed = NULL;
1534                 lock_chunks(root);
1535                 __btrfs_close_devices(cur_devices);
1536                 unlock_chunks(root);
1537                 free_fs_devices(cur_devices);
1538         }
1539
1540         root->fs_info->num_tolerated_disk_barrier_failures =
1541                 btrfs_calc_num_tolerated_disk_barrier_failures(root->fs_info);
1542
1543         /*
1544          * at this point, the device is zero sized.  We want to
1545          * remove it from the devices list and zero out the old super
1546          */
1547         if (clear_super && disk_super) {
1548                 /* make sure this device isn't detected as part of
1549                  * the FS anymore
1550                  */
1551                 memset(&disk_super->magic, 0, sizeof(disk_super->magic));
1552                 set_buffer_dirty(bh);
1553                 sync_dirty_buffer(bh);
1554         }
1555
1556         ret = 0;
1557
1558         /* Notify udev that device has changed */
1559         btrfs_kobject_uevent(bdev, KOBJ_CHANGE);
1560
1561 error_brelse:
1562         brelse(bh);
1563         if (bdev)
1564                 blkdev_put(bdev, FMODE_READ | FMODE_EXCL);
1565 out:
1566         mutex_unlock(&uuid_mutex);
1567         return ret;
1568 error_undo:
1569         if (device->writeable) {
1570                 lock_chunks(root);
1571                 list_add(&device->dev_alloc_list,
1572                          &root->fs_info->fs_devices->alloc_list);
1573                 unlock_chunks(root);
1574                 root->fs_info->fs_devices->rw_devices++;
1575         }
1576         goto error_brelse;
1577 }
1578
1579 void btrfs_rm_dev_replace_srcdev(struct btrfs_fs_info *fs_info,
1580                                  struct btrfs_device *srcdev)
1581 {
1582         WARN_ON(!mutex_is_locked(&fs_info->fs_devices->device_list_mutex));
1583         list_del_rcu(&srcdev->dev_list);
1584         list_del_rcu(&srcdev->dev_alloc_list);
1585         fs_info->fs_devices->num_devices--;
1586         if (srcdev->missing) {
1587                 fs_info->fs_devices->missing_devices--;
1588                 fs_info->fs_devices->rw_devices++;
1589         }
1590         if (srcdev->can_discard)
1591                 fs_info->fs_devices->num_can_discard--;
1592         if (srcdev->bdev)
1593                 fs_info->fs_devices->open_devices--;
1594
1595         call_rcu(&srcdev->rcu, free_device);
1596 }
1597
1598 void btrfs_destroy_dev_replace_tgtdev(struct btrfs_fs_info *fs_info,
1599                                       struct btrfs_device *tgtdev)
1600 {
1601         struct btrfs_device *next_device;
1602
1603         WARN_ON(!tgtdev);
1604         mutex_lock(&fs_info->fs_devices->device_list_mutex);
1605         if (tgtdev->bdev) {
1606                 btrfs_scratch_superblock(tgtdev);
1607                 fs_info->fs_devices->open_devices--;
1608         }
1609         fs_info->fs_devices->num_devices--;
1610         if (tgtdev->can_discard)
1611                 fs_info->fs_devices->num_can_discard++;
1612
1613         next_device = list_entry(fs_info->fs_devices->devices.next,
1614                                  struct btrfs_device, dev_list);
1615         if (tgtdev->bdev == fs_info->sb->s_bdev)
1616                 fs_info->sb->s_bdev = next_device->bdev;
1617         if (tgtdev->bdev == fs_info->fs_devices->latest_bdev)
1618                 fs_info->fs_devices->latest_bdev = next_device->bdev;
1619         list_del_rcu(&tgtdev->dev_list);
1620
1621         call_rcu(&tgtdev->rcu, free_device);
1622
1623         mutex_unlock(&fs_info->fs_devices->device_list_mutex);
1624 }
1625
1626 int btrfs_find_device_by_path(struct btrfs_root *root, char *device_path,
1627                               struct btrfs_device **device)
1628 {
1629         int ret = 0;
1630         struct btrfs_super_block *disk_super;
1631         u64 devid;
1632         u8 *dev_uuid;
1633         struct block_device *bdev;
1634         struct buffer_head *bh;
1635
1636         *device = NULL;
1637         ret = btrfs_get_bdev_and_sb(device_path, FMODE_READ,
1638                                     root->fs_info->bdev_holder, 0, &bdev, &bh);
1639         if (ret)
1640                 return ret;
1641         disk_super = (struct btrfs_super_block *)bh->b_data;
1642         devid = btrfs_stack_device_id(&disk_super->dev_item);
1643         dev_uuid = disk_super->dev_item.uuid;
1644         *device = btrfs_find_device(root->fs_info, devid, dev_uuid,
1645                                     disk_super->fsid);
1646         brelse(bh);
1647         if (!*device)
1648                 ret = -ENOENT;
1649         blkdev_put(bdev, FMODE_READ);
1650         return ret;
1651 }
1652
1653 int btrfs_find_device_missing_or_by_path(struct btrfs_root *root,
1654                                          char *device_path,
1655                                          struct btrfs_device **device)
1656 {
1657         *device = NULL;
1658         if (strcmp(device_path, "missing") == 0) {
1659                 struct list_head *devices;
1660                 struct btrfs_device *tmp;
1661
1662                 devices = &root->fs_info->fs_devices->devices;
1663                 /*
1664                  * It is safe to read the devices since the volume_mutex
1665                  * is held by the caller.
1666                  */
1667                 list_for_each_entry(tmp, devices, dev_list) {
1668                         if (tmp->in_fs_metadata && !tmp->bdev) {
1669                                 *device = tmp;
1670                                 break;
1671                         }
1672                 }
1673
1674                 if (!*device) {
1675                         pr_err("btrfs: no missing device found\n");
1676                         return -ENOENT;
1677                 }
1678
1679                 return 0;
1680         } else {
1681                 return btrfs_find_device_by_path(root, device_path, device);
1682         }
1683 }
1684
1685 /*
1686  * does all the dirty work required for changing file system's UUID.
1687  */
1688 static int btrfs_prepare_sprout(struct btrfs_root *root)
1689 {
1690         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
1691         struct btrfs_fs_devices *old_devices;
1692         struct btrfs_fs_devices *seed_devices;
1693         struct btrfs_super_block *disk_super = root->fs_info->super_copy;
1694         struct btrfs_device *device;
1695         u64 super_flags;
1696
1697         BUG_ON(!mutex_is_locked(&uuid_mutex));
1698         if (!fs_devices->seeding)
1699                 return -EINVAL;
1700
1701         seed_devices = kzalloc(sizeof(*fs_devices), GFP_NOFS);
1702         if (!seed_devices)
1703                 return -ENOMEM;
1704
1705         old_devices = clone_fs_devices(fs_devices);
1706         if (IS_ERR(old_devices)) {
1707                 kfree(seed_devices);
1708                 return PTR_ERR(old_devices);
1709         }
1710
1711         list_add(&old_devices->list, &fs_uuids);
1712
1713         memcpy(seed_devices, fs_devices, sizeof(*seed_devices));
1714         seed_devices->opened = 1;
1715         INIT_LIST_HEAD(&seed_devices->devices);
1716         INIT_LIST_HEAD(&seed_devices->alloc_list);
1717         mutex_init(&seed_devices->device_list_mutex);
1718
1719         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
1720         list_splice_init_rcu(&fs_devices->devices, &seed_devices->devices,
1721                               synchronize_rcu);
1722         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1723
1724         list_splice_init(&fs_devices->alloc_list, &seed_devices->alloc_list);
1725         list_for_each_entry(device, &seed_devices->devices, dev_list) {
1726                 device->fs_devices = seed_devices;
1727         }
1728
1729         fs_devices->seeding = 0;
1730         fs_devices->num_devices = 0;
1731         fs_devices->open_devices = 0;
1732         fs_devices->total_devices = 0;
1733         fs_devices->seed = seed_devices;
1734
1735         generate_random_uuid(fs_devices->fsid);
1736         memcpy(root->fs_info->fsid, fs_devices->fsid, BTRFS_FSID_SIZE);
1737         memcpy(disk_super->fsid, fs_devices->fsid, BTRFS_FSID_SIZE);
1738         super_flags = btrfs_super_flags(disk_super) &
1739                       ~BTRFS_SUPER_FLAG_SEEDING;
1740         btrfs_set_super_flags(disk_super, super_flags);
1741
1742         return 0;
1743 }
1744
1745 /*
1746  * strore the expected generation for seed devices in device items.
1747  */
1748 static int btrfs_finish_sprout(struct btrfs_trans_handle *trans,
1749                                struct btrfs_root *root)
1750 {
1751         struct btrfs_path *path;
1752         struct extent_buffer *leaf;
1753         struct btrfs_dev_item *dev_item;
1754         struct btrfs_device *device;
1755         struct btrfs_key key;
1756         u8 fs_uuid[BTRFS_UUID_SIZE];
1757         u8 dev_uuid[BTRFS_UUID_SIZE];
1758         u64 devid;
1759         int ret;
1760
1761         path = btrfs_alloc_path();
1762         if (!path)
1763                 return -ENOMEM;
1764
1765         root = root->fs_info->chunk_root;
1766         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1767         key.offset = 0;
1768         key.type = BTRFS_DEV_ITEM_KEY;
1769
1770         while (1) {
1771                 ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
1772                 if (ret < 0)
1773                         goto error;
1774
1775                 leaf = path->nodes[0];
1776 next_slot:
1777                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
1778                         ret = btrfs_next_leaf(root, path);
1779                         if (ret > 0)
1780                                 break;
1781                         if (ret < 0)
1782                                 goto error;
1783                         leaf = path->nodes[0];
1784                         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1785                         btrfs_release_path(path);
1786                         continue;
1787                 }
1788
1789                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1790                 if (key.objectid != BTRFS_DEV_ITEMS_OBJECTID ||
1791                     key.type != BTRFS_DEV_ITEM_KEY)
1792                         break;
1793
1794                 dev_item = btrfs_item_ptr(leaf, path->slots[0],
1795                                           struct btrfs_dev_item);
1796                 devid = btrfs_device_id(leaf, dev_item);
1797                 read_extent_buffer(leaf, dev_uuid,
1798                                    (unsigned long)btrfs_device_uuid(dev_item),
1799                                    BTRFS_UUID_SIZE);
1800                 read_extent_buffer(leaf, fs_uuid,
1801                                    (unsigned long)btrfs_device_fsid(dev_item),
1802                                    BTRFS_UUID_SIZE);
1803                 device = btrfs_find_device(root->fs_info, devid, dev_uuid,
1804                                            fs_uuid);
1805                 BUG_ON(!device); /* Logic error */
1806
1807                 if (device->fs_devices->seeding) {
1808                         btrfs_set_device_generation(leaf, dev_item,
1809                                                     device->generation);
1810                         btrfs_mark_buffer_dirty(leaf);
1811                 }
1812
1813                 path->slots[0]++;
1814                 goto next_slot;
1815         }
1816         ret = 0;
1817 error:
1818         btrfs_free_path(path);
1819         return ret;
1820 }
1821
1822 int btrfs_init_new_device(struct btrfs_root *root, char *device_path)
1823 {
1824         struct request_queue *q;
1825         struct btrfs_trans_handle *trans;
1826         struct btrfs_device *device;
1827         struct block_device *bdev;
1828         struct list_head *devices;
1829         struct super_block *sb = root->fs_info->sb;
1830         struct rcu_string *name;
1831         u64 total_bytes;
1832         int seeding_dev = 0;
1833         int ret = 0;
1834
1835         if ((sb->s_flags & MS_RDONLY) && !root->fs_info->fs_devices->seeding)
1836                 return -EROFS;
1837
1838         bdev = blkdev_get_by_path(device_path, FMODE_WRITE | FMODE_EXCL,
1839                                   root->fs_info->bdev_holder);
1840         if (IS_ERR(bdev))
1841                 return PTR_ERR(bdev);
1842
1843         if (root->fs_info->fs_devices->seeding) {
1844                 seeding_dev = 1;
1845                 down_write(&sb->s_umount);
1846                 mutex_lock(&uuid_mutex);
1847         }
1848
1849         filemap_write_and_wait(bdev->bd_inode->i_mapping);
1850
1851         devices = &root->fs_info->fs_devices->devices;
1852
1853         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
1854         list_for_each_entry(device, devices, dev_list) {
1855                 if (device->bdev == bdev) {
1856                         ret = -EEXIST;
1857                         mutex_unlock(
1858                                 &root->fs_info->fs_devices->device_list_mutex);
1859                         goto error;
1860                 }
1861         }
1862         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1863
1864         device = kzalloc(sizeof(*device), GFP_NOFS);
1865         if (!device) {
1866                 /* we can safely leave the fs_devices entry around */
1867                 ret = -ENOMEM;
1868                 goto error;
1869         }
1870
1871         name = rcu_string_strdup(device_path, GFP_NOFS);
1872         if (!name) {
1873                 kfree(device);
1874                 ret = -ENOMEM;
1875                 goto error;
1876         }
1877         rcu_assign_pointer(device->name, name);
1878
1879         ret = find_next_devid(root, &device->devid);
1880         if (ret) {
1881                 rcu_string_free(device->name);
1882                 kfree(device);
1883                 goto error;
1884         }
1885
1886         trans = btrfs_start_transaction(root, 0);
1887         if (IS_ERR(trans)) {
1888                 rcu_string_free(device->name);
1889                 kfree(device);
1890                 ret = PTR_ERR(trans);
1891                 goto error;
1892         }
1893
1894         lock_chunks(root);
1895
1896         q = bdev_get_queue(bdev);
1897         if (blk_queue_discard(q))
1898                 device->can_discard = 1;
1899         device->writeable = 1;
1900         device->work.func = pending_bios_fn;
1901         generate_random_uuid(device->uuid);
1902         spin_lock_init(&device->io_lock);
1903         device->generation = trans->transid;
1904         device->io_width = root->sectorsize;
1905         device->io_align = root->sectorsize;
1906         device->sector_size = root->sectorsize;
1907         device->total_bytes = i_size_read(bdev->bd_inode);
1908         device->disk_total_bytes = device->total_bytes;
1909         device->dev_root = root->fs_info->dev_root;
1910         device->bdev = bdev;
1911         device->in_fs_metadata = 1;
1912         device->is_tgtdev_for_dev_replace = 0;
1913         device->mode = FMODE_EXCL;
1914         set_blocksize(device->bdev, 4096);
1915
1916         if (seeding_dev) {
1917                 sb->s_flags &= ~MS_RDONLY;
1918                 ret = btrfs_prepare_sprout(root);
1919                 BUG_ON(ret); /* -ENOMEM */
1920         }
1921
1922         device->fs_devices = root->fs_info->fs_devices;
1923
1924         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
1925         list_add_rcu(&device->dev_list, &root->fs_info->fs_devices->devices);
1926         list_add(&device->dev_alloc_list,
1927                  &root->fs_info->fs_devices->alloc_list);
1928         root->fs_info->fs_devices->num_devices++;
1929         root->fs_info->fs_devices->open_devices++;
1930         root->fs_info->fs_devices->rw_devices++;
1931         root->fs_info->fs_devices->total_devices++;
1932         if (device->can_discard)
1933                 root->fs_info->fs_devices->num_can_discard++;
1934         root->fs_info->fs_devices->total_rw_bytes += device->total_bytes;
1935
1936         spin_lock(&root->fs_info->free_chunk_lock);
1937         root->fs_info->free_chunk_space += device->total_bytes;
1938         spin_unlock(&root->fs_info->free_chunk_lock);
1939
1940         if (!blk_queue_nonrot(bdev_get_queue(bdev)))
1941                 root->fs_info->fs_devices->rotating = 1;
1942
1943         total_bytes = btrfs_super_total_bytes(root->fs_info->super_copy);
1944         btrfs_set_super_total_bytes(root->fs_info->super_copy,
1945                                     total_bytes + device->total_bytes);
1946
1947         total_bytes = btrfs_super_num_devices(root->fs_info->super_copy);
1948         btrfs_set_super_num_devices(root->fs_info->super_copy,
1949                                     total_bytes + 1);
1950         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1951
1952         if (seeding_dev) {
1953                 ret = init_first_rw_device(trans, root, device);
1954                 if (ret) {
1955                         btrfs_abort_transaction(trans, root, ret);
1956                         goto error_trans;
1957                 }
1958                 ret = btrfs_finish_sprout(trans, root);
1959                 if (ret) {
1960                         btrfs_abort_transaction(trans, root, ret);
1961                         goto error_trans;
1962                 }
1963         } else {
1964                 ret = btrfs_add_device(trans, root, device);
1965                 if (ret) {
1966                         btrfs_abort_transaction(trans, root, ret);
1967                         goto error_trans;
1968                 }
1969         }
1970
1971         /*
1972          * we've got more storage, clear any full flags on the space
1973          * infos
1974          */
1975         btrfs_clear_space_info_full(root->fs_info);
1976
1977         unlock_chunks(root);
1978         root->fs_info->num_tolerated_disk_barrier_failures =
1979                 btrfs_calc_num_tolerated_disk_barrier_failures(root->fs_info);
1980         ret = btrfs_commit_transaction(trans, root);
1981
1982         if (seeding_dev) {
1983                 mutex_unlock(&uuid_mutex);
1984                 up_write(&sb->s_umount);
1985
1986                 if (ret) /* transaction commit */
1987                         return ret;
1988
1989                 ret = btrfs_relocate_sys_chunks(root);
1990                 if (ret < 0)
1991                         btrfs_error(root->fs_info, ret,
1992                                     "Failed to relocate sys chunks after "
1993                                     "device initialization. This can be fixed "
1994                                     "using the \"btrfs balance\" command.");
1995                 trans = btrfs_attach_transaction(root);
1996                 if (IS_ERR(trans)) {
1997                         if (PTR_ERR(trans) == -ENOENT)
1998                                 return 0;
1999                         return PTR_ERR(trans);
2000                 }
2001                 ret = btrfs_commit_transaction(trans, root);
2002         }
2003
2004         return ret;
2005
2006 error_trans:
2007         unlock_chunks(root);
2008         btrfs_end_transaction(trans, root);
2009         rcu_string_free(device->name);
2010         kfree(device);
2011 error:
2012         blkdev_put(bdev, FMODE_EXCL);
2013         if (seeding_dev) {
2014                 mutex_unlock(&uuid_mutex);
2015                 up_write(&sb->s_umount);
2016         }
2017         return ret;
2018 }
2019
2020 int btrfs_init_dev_replace_tgtdev(struct btrfs_root *root, char *device_path,
2021                                   struct btrfs_device **device_out)
2022 {
2023         struct request_queue *q;
2024         struct btrfs_device *device;
2025         struct block_device *bdev;
2026         struct btrfs_fs_info *fs_info = root->fs_info;
2027         struct list_head *devices;
2028         struct rcu_string *name;
2029         int ret = 0;
2030
2031         *device_out = NULL;
2032         if (fs_info->fs_devices->seeding)
2033                 return -EINVAL;
2034
2035         bdev = blkdev_get_by_path(device_path, FMODE_WRITE | FMODE_EXCL,
2036                                   fs_info->bdev_holder);
2037         if (IS_ERR(bdev))
2038                 return PTR_ERR(bdev);
2039
2040         filemap_write_and_wait(bdev->bd_inode->i_mapping);
2041
2042         devices = &fs_info->fs_devices->devices;
2043         list_for_each_entry(device, devices, dev_list) {
2044                 if (device->bdev == bdev) {
2045                         ret = -EEXIST;
2046                         goto error;
2047                 }
2048         }
2049
2050         device = kzalloc(sizeof(*device), GFP_NOFS);
2051         if (!device) {
2052                 ret = -ENOMEM;
2053                 goto error;
2054         }
2055
2056         name = rcu_string_strdup(device_path, GFP_NOFS);
2057         if (!name) {
2058                 kfree(device);
2059                 ret = -ENOMEM;
2060                 goto error;
2061         }
2062         rcu_assign_pointer(device->name, name);
2063
2064         q = bdev_get_queue(bdev);
2065         if (blk_queue_discard(q))
2066                 device->can_discard = 1;
2067         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
2068         device->writeable = 1;
2069         device->work.func = pending_bios_fn;
2070         generate_random_uuid(device->uuid);
2071         device->devid = BTRFS_DEV_REPLACE_DEVID;
2072         spin_lock_init(&device->io_lock);
2073         device->generation = 0;
2074         device->io_width = root->sectorsize;
2075         device->io_align = root->sectorsize;
2076         device->sector_size = root->sectorsize;
2077         device->total_bytes = i_size_read(bdev->bd_inode);
2078         device->disk_total_bytes = device->total_bytes;
2079         device->dev_root = fs_info->dev_root;
2080         device->bdev = bdev;
2081         device->in_fs_metadata = 1;
2082         device->is_tgtdev_for_dev_replace = 1;
2083         device->mode = FMODE_EXCL;
2084         set_blocksize(device->bdev, 4096);
2085         device->fs_devices = fs_info->fs_devices;
2086         list_add(&device->dev_list, &fs_info->fs_devices->devices);
2087         fs_info->fs_devices->num_devices++;
2088         fs_info->fs_devices->open_devices++;
2089         if (device->can_discard)
2090                 fs_info->fs_devices->num_can_discard++;
2091         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
2092
2093         *device_out = device;
2094         return ret;
2095
2096 error:
2097         blkdev_put(bdev, FMODE_EXCL);
2098         return ret;
2099 }
2100
2101 void btrfs_init_dev_replace_tgtdev_for_resume(struct btrfs_fs_info *fs_info,
2102                                               struct btrfs_device *tgtdev)
2103 {
2104         WARN_ON(fs_info->fs_devices->rw_devices == 0);
2105         tgtdev->io_width = fs_info->dev_root->sectorsize;
2106         tgtdev->io_align = fs_info->dev_root->sectorsize;
2107         tgtdev->sector_size = fs_info->dev_root->sectorsize;
2108         tgtdev->dev_root = fs_info->dev_root;
2109         tgtdev->in_fs_metadata = 1;
2110 }
2111
2112 static noinline int btrfs_update_device(struct btrfs_trans_handle *trans,
2113                                         struct btrfs_device *device)
2114 {
2115         int ret;
2116         struct btrfs_path *path;
2117         struct btrfs_root *root;
2118         struct btrfs_dev_item *dev_item;
2119         struct extent_buffer *leaf;
2120         struct btrfs_key key;
2121
2122         root = device->dev_root->fs_info->chunk_root;
2123
2124         path = btrfs_alloc_path();
2125         if (!path)
2126                 return -ENOMEM;
2127
2128         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
2129         key.type = BTRFS_DEV_ITEM_KEY;
2130         key.offset = device->devid;
2131
2132         ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
2133         if (ret < 0)
2134                 goto out;
2135
2136         if (ret > 0) {
2137                 ret = -ENOENT;
2138                 goto out;
2139         }
2140
2141         leaf = path->nodes[0];
2142         dev_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dev_item);
2143
2144         btrfs_set_device_id(leaf, dev_item, device->devid);
2145         btrfs_set_device_type(leaf, dev_item, device->type);
2146         btrfs_set_device_io_align(leaf, dev_item, device->io_align);
2147         btrfs_set_device_io_width(leaf, dev_item, device->io_width);
2148         btrfs_set_device_sector_size(leaf, dev_item, device->sector_size);
2149         btrfs_set_device_total_bytes(leaf, dev_item, device->disk_total_bytes);
2150         btrfs_set_device_bytes_used(leaf, dev_item, device->bytes_used);
2151         btrfs_mark_buffer_dirty(leaf);
2152
2153 out:
2154         btrfs_free_path(path);
2155         return ret;
2156 }
2157
2158 static int __btrfs_grow_device(struct btrfs_trans_handle *trans,
2159                       struct btrfs_device *device, u64 new_size)
2160 {
2161         struct btrfs_super_block *super_copy =
2162                 device->dev_root->fs_info->super_copy;
2163         u64 old_total = btrfs_super_total_bytes(super_copy);
2164         u64 diff = new_size - device->total_bytes;
2165
2166         if (!device->writeable)
2167                 return -EACCES;
2168         if (new_size <= device->total_bytes ||
2169             device->is_tgtdev_for_dev_replace)
2170                 return -EINVAL;
2171
2172         btrfs_set_super_total_bytes(super_copy, old_total + diff);
2173         device->fs_devices->total_rw_bytes += diff;
2174
2175         device->total_bytes = new_size;
2176         device->disk_total_bytes = new_size;
2177         btrfs_clear_space_info_full(device->dev_root->fs_info);
2178
2179         return btrfs_update_device(trans, device);
2180 }
2181
2182 int btrfs_grow_device(struct btrfs_trans_handle *trans,
2183                       struct btrfs_device *device, u64 new_size)
2184 {
2185         int ret;
2186         lock_chunks(device->dev_root);
2187         ret = __btrfs_grow_device(trans, device, new_size);
2188         unlock_chunks(device->dev_root);
2189         return ret;
2190 }
2191
2192 static int btrfs_free_chunk(struct btrfs_trans_handle *trans,
2193                             struct btrfs_root *root,
2194                             u64 chunk_tree, u64 chunk_objectid,
2195                             u64 chunk_offset)
2196 {
2197         int ret;
2198         struct btrfs_path *path;
2199         struct btrfs_key key;
2200
2201         root = root->fs_info->chunk_root;
2202         path = btrfs_alloc_path();
2203         if (!path)
2204                 return -ENOMEM;
2205
2206         key.objectid = chunk_objectid;
2207         key.offset = chunk_offset;
2208         key.type = BTRFS_CHUNK_ITEM_KEY;
2209
2210         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
2211         if (ret < 0)
2212                 goto out;
2213         else if (ret > 0) { /* Logic error or corruption */
2214                 btrfs_error(root->fs_info, -ENOENT,
2215                             "Failed lookup while freeing chunk.");
2216                 ret = -ENOENT;
2217                 goto out;
2218         }
2219
2220         ret = btrfs_del_item(trans, root, path);
2221         if (ret < 0)
2222                 btrfs_error(root->fs_info, ret,
2223                             "Failed to delete chunk item.");
2224 out:
2225         btrfs_free_path(path);
2226         return ret;
2227 }
2228
2229 static int btrfs_del_sys_chunk(struct btrfs_root *root, u64 chunk_objectid, u64
2230                         chunk_offset)
2231 {
2232         struct btrfs_super_block *super_copy = root->fs_info->super_copy;
2233         struct btrfs_disk_key *disk_key;
2234         struct btrfs_chunk *chunk;
2235         u8 *ptr;
2236         int ret = 0;
2237         u32 num_stripes;
2238         u32 array_size;
2239         u32 len = 0;
2240         u32 cur;
2241         struct btrfs_key key;
2242
2243         array_size = btrfs_super_sys_array_size(super_copy);
2244
2245         ptr = super_copy->sys_chunk_array;
2246         cur = 0;
2247
2248         while (cur < array_size) {
2249                 disk_key = (struct btrfs_disk_key *)ptr;
2250                 btrfs_disk_key_to_cpu(&key, disk_key);
2251
2252                 len = sizeof(*disk_key);
2253
2254                 if (key.type == BTRFS_CHUNK_ITEM_KEY) {
2255                         chunk = (struct btrfs_chunk *)(ptr + len);
2256                         num_stripes = btrfs_stack_chunk_num_stripes(chunk);
2257                         len += btrfs_chunk_item_size(num_stripes);
2258                 } else {
2259                         ret = -EIO;
2260                         break;
2261                 }
2262                 if (key.objectid == chunk_objectid &&
2263                     key.offset == chunk_offset) {
2264                         memmove(ptr, ptr + len, array_size - (cur + len));
2265                         array_size -= len;
2266                         btrfs_set_super_sys_array_size(super_copy, array_size);
2267                 } else {
2268                         ptr += len;
2269                         cur += len;
2270                 }
2271         }
2272         return ret;
2273 }
2274
2275 static int btrfs_relocate_chunk(struct btrfs_root *root,
2276                          u64 chunk_tree, u64 chunk_objectid,
2277                          u64 chunk_offset)
2278 {
2279         struct extent_map_tree *em_tree;
2280         struct btrfs_root *extent_root;
2281         struct btrfs_trans_handle *trans;
2282         struct extent_map *em;
2283         struct map_lookup *map;
2284         int ret;
2285         int i;
2286
2287         root = root->fs_info->chunk_root;
2288         extent_root = root->fs_info->extent_root;
2289         em_tree = &root->fs_info->mapping_tree.map_tree;
2290
2291         ret = btrfs_can_relocate(extent_root, chunk_offset);
2292         if (ret)
2293                 return -ENOSPC;
2294
2295         /* step one, relocate all the extents inside this chunk */
2296         ret = btrfs_relocate_block_group(extent_root, chunk_offset);
2297         if (ret)
2298                 return ret;
2299
2300         trans = btrfs_start_transaction(root, 0);
2301         BUG_ON(IS_ERR(trans));
2302
2303         lock_chunks(root);
2304
2305         /*
2306          * step two, delete the device extents and the
2307          * chunk tree entries
2308          */
2309         read_lock(&em_tree->lock);
2310         em = lookup_extent_mapping(em_tree, chunk_offset, 1);
2311         read_unlock(&em_tree->lock);
2312
2313         BUG_ON(!em || em->start > chunk_offset ||
2314                em->start + em->len < chunk_offset);
2315         map = (struct map_lookup *)em->bdev;
2316
2317         for (i = 0; i < map->num_stripes; i++) {
2318                 ret = btrfs_free_dev_extent(trans, map->stripes[i].dev,
2319                                             map->stripes[i].physical);
2320                 BUG_ON(ret);
2321
2322                 if (map->stripes[i].dev) {
2323                         ret = btrfs_update_device(trans, map->stripes[i].dev);
2324                         BUG_ON(ret);
2325                 }
2326         }
2327         ret = btrfs_free_chunk(trans, root, chunk_tree, chunk_objectid,
2328                                chunk_offset);
2329
2330         BUG_ON(ret);
2331
2332         trace_btrfs_chunk_free(root, map, chunk_offset, em->len);
2333
2334         if (map->type & BTRFS_BLOCK_GROUP_SYSTEM) {
2335                 ret = btrfs_del_sys_chunk(root, chunk_objectid, chunk_offset);
2336                 BUG_ON(ret);
2337         }
2338
2339         ret = btrfs_remove_block_group(trans, extent_root, chunk_offset);
2340         BUG_ON(ret);
2341
2342         write_lock(&em_tree->lock);
2343         remove_extent_mapping(em_tree, em);
2344         write_unlock(&em_tree->lock);
2345
2346         kfree(map);
2347         em->bdev = NULL;
2348
2349         /* once for the tree */
2350         free_extent_map(em);
2351         /* once for us */
2352         free_extent_map(em);
2353
2354         unlock_chunks(root);
2355         btrfs_end_transaction(trans, root);
2356         return 0;
2357 }
2358
2359 static int btrfs_relocate_sys_chunks(struct btrfs_root *root)
2360 {
2361         struct btrfs_root *chunk_root = root->fs_info->chunk_root;
2362         struct btrfs_path *path;
2363         struct extent_buffer *leaf;
2364         struct btrfs_chunk *chunk;
2365         struct btrfs_key key;
2366         struct btrfs_key found_key;
2367         u64 chunk_tree = chunk_root->root_key.objectid;
2368         u64 chunk_type;
2369         bool retried = false;
2370         int failed = 0;
2371         int ret;
2372
2373         path = btrfs_alloc_path();
2374         if (!path)
2375                 return -ENOMEM;
2376
2377 again:
2378         key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
2379         key.offset = (u64)-1;
2380         key.type = BTRFS_CHUNK_ITEM_KEY;
2381
2382         while (1) {
2383                 ret = btrfs_search_slot(NULL, chunk_root, &key, path, 0, 0);
2384                 if (ret < 0)
2385                         goto error;
2386                 BUG_ON(ret == 0); /* Corruption */
2387
2388                 ret = btrfs_previous_item(chunk_root, path, key.objectid,
2389                                           key.type);
2390                 if (ret < 0)
2391                         goto error;
2392                 if (ret > 0)
2393                         break;
2394
2395                 leaf = path->nodes[0];
2396                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2397
2398                 chunk = btrfs_item_ptr(leaf, path->slots[0],
2399                                        struct btrfs_chunk);
2400                 chunk_type = btrfs_chunk_type(leaf, chunk);
2401                 btrfs_release_path(path);
2402
2403                 if (chunk_type & BTRFS_BLOCK_GROUP_SYSTEM) {
2404                         ret = btrfs_relocate_chunk(chunk_root, chunk_tree,
2405                                                    found_key.objectid,
2406                                                    found_key.offset);
2407                         if (ret == -ENOSPC)
2408                                 failed++;
2409                         else if (ret)
2410                                 BUG();
2411                 }
2412
2413                 if (found_key.offset == 0)
2414                         break;
2415                 key.offset = found_key.offset - 1;
2416         }
2417         ret = 0;
2418         if (failed && !retried) {
2419                 failed = 0;
2420                 retried = true;
2421                 goto again;
2422         } else if (failed && retried) {
2423                 WARN_ON(1);
2424                 ret = -ENOSPC;
2425         }
2426 error:
2427         btrfs_free_path(path);
2428         return ret;
2429 }
2430
2431 static int insert_balance_item(struct btrfs_root *root,
2432                                struct btrfs_balance_control *bctl)
2433 {
2434         struct btrfs_trans_handle *trans;
2435         struct btrfs_balance_item *item;
2436         struct btrfs_disk_balance_args disk_bargs;
2437         struct btrfs_path *path;
2438         struct extent_buffer *leaf;
2439         struct btrfs_key key;
2440         int ret, err;
2441
2442         path = btrfs_alloc_path();
2443         if (!path)
2444                 return -ENOMEM;
2445
2446         trans = btrfs_start_transaction(root, 0);
2447         if (IS_ERR(trans)) {
2448                 btrfs_free_path(path);
2449                 return PTR_ERR(trans);
2450         }
2451
2452         key.objectid = BTRFS_BALANCE_OBJECTID;
2453         key.type = BTRFS_BALANCE_ITEM_KEY;
2454         key.offset = 0;
2455
2456         ret = btrfs_insert_empty_item(trans, root, path, &key,
2457                                       sizeof(*item));
2458         if (ret)
2459                 goto out;
2460
2461         leaf = path->nodes[0];
2462         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_balance_item);
2463
2464         memset_extent_buffer(leaf, 0, (unsigned long)item, sizeof(*item));
2465
2466         btrfs_cpu_balance_args_to_disk(&disk_bargs, &bctl->data);
2467         btrfs_set_balance_data(leaf, item, &disk_bargs);
2468         btrfs_cpu_balance_args_to_disk(&disk_bargs, &bctl->meta);
2469         btrfs_set_balance_meta(leaf, item, &disk_bargs);
2470         btrfs_cpu_balance_args_to_disk(&disk_bargs, &bctl->sys);
2471         btrfs_set_balance_sys(leaf, item, &disk_bargs);
2472
2473         btrfs_set_balance_flags(leaf, item, bctl->flags);
2474
2475         btrfs_mark_buffer_dirty(leaf);
2476 out:
2477         btrfs_free_path(path);
2478         err = btrfs_commit_transaction(trans, root);
2479         if (err && !ret)
2480                 ret = err;
2481         return ret;
2482 }
2483
2484 static int del_balance_item(struct btrfs_root *root)
2485 {
2486         struct btrfs_trans_handle *trans;
2487         struct btrfs_path *path;
2488         struct btrfs_key key;
2489         int ret, err;
2490
2491         path = btrfs_alloc_path();
2492         if (!path)
2493                 return -ENOMEM;
2494
2495         trans = btrfs_start_transaction(root, 0);
2496         if (IS_ERR(trans)) {
2497                 btrfs_free_path(path);
2498                 return PTR_ERR(trans);
2499         }
2500
2501         key.objectid = BTRFS_BALANCE_OBJECTID;
2502         key.type = BTRFS_BALANCE_ITEM_KEY;
2503         key.offset = 0;
2504
2505         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
2506         if (ret < 0)
2507                 goto out;
2508         if (ret > 0) {
2509                 ret = -ENOENT;
2510                 goto out;
2511         }
2512
2513         ret = btrfs_del_item(trans, root, path);
2514 out:
2515         btrfs_free_path(path);
2516         err = btrfs_commit_transaction(trans, root);
2517         if (err && !ret)
2518                 ret = err;
2519         return ret;
2520 }
2521
2522 /*
2523  * This is a heuristic used to reduce the number of chunks balanced on
2524  * resume after balance was interrupted.
2525  */
2526 static void update_balance_args(struct btrfs_balance_control *bctl)
2527 {
2528         /*
2529          * Turn on soft mode for chunk types that were being converted.
2530          */
2531         if (bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT)
2532                 bctl->data.flags |= BTRFS_BALANCE_ARGS_SOFT;
2533         if (bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT)
2534                 bctl->sys.flags |= BTRFS_BALANCE_ARGS_SOFT;
2535         if (bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT)
2536                 bctl->meta.flags |= BTRFS_BALANCE_ARGS_SOFT;
2537
2538         /*
2539          * Turn on usage filter if is not already used.  The idea is
2540          * that chunks that we have already balanced should be
2541          * reasonably full.  Don't do it for chunks that are being
2542          * converted - that will keep us from relocating unconverted
2543          * (albeit full) chunks.
2544          */
2545         if (!(bctl->data.flags & BTRFS_BALANCE_ARGS_USAGE) &&
2546             !(bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT)) {
2547                 bctl->data.flags |= BTRFS_BALANCE_ARGS_USAGE;
2548                 bctl->data.usage = 90;
2549         }
2550         if (!(bctl->sys.flags & BTRFS_BALANCE_ARGS_USAGE) &&
2551             !(bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT)) {
2552                 bctl->sys.flags |= BTRFS_BALANCE_ARGS_USAGE;
2553                 bctl->sys.usage = 90;
2554         }
2555         if (!(bctl->meta.flags & BTRFS_BALANCE_ARGS_USAGE) &&
2556             !(bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT)) {
2557                 bctl->meta.flags |= BTRFS_BALANCE_ARGS_USAGE;
2558                 bctl->meta.usage = 90;
2559         }
2560 }
2561
2562 /*
2563  * Should be called with both balance and volume mutexes held to
2564  * serialize other volume operations (add_dev/rm_dev/resize) with
2565  * restriper.  Same goes for unset_balance_control.
2566  */
2567 static void set_balance_control(struct btrfs_balance_control *bctl)
2568 {
2569         struct btrfs_fs_info *fs_info = bctl->fs_info;
2570
2571         BUG_ON(fs_info->balance_ctl);
2572
2573         spin_lock(&fs_info->balance_lock);
2574         fs_info->balance_ctl = bctl;
2575         spin_unlock(&fs_info->balance_lock);
2576 }
2577
2578 static void unset_balance_control(struct btrfs_fs_info *fs_info)
2579 {
2580         struct btrfs_balance_control *bctl = fs_info->balance_ctl;
2581
2582         BUG_ON(!fs_info->balance_ctl);
2583
2584         spin_lock(&fs_info->balance_lock);
2585         fs_info->balance_ctl = NULL;
2586         spin_unlock(&fs_info->balance_lock);
2587
2588         kfree(bctl);
2589 }
2590
2591 /*
2592  * Balance filters.  Return 1 if chunk should be filtered out
2593  * (should not be balanced).
2594  */
2595 static int chunk_profiles_filter(u64 chunk_type,
2596                                  struct btrfs_balance_args *bargs)
2597 {
2598         chunk_type = chunk_to_extended(chunk_type) &
2599                                 BTRFS_EXTENDED_PROFILE_MASK;
2600
2601         if (bargs->profiles & chunk_type)
2602                 return 0;
2603
2604         return 1;
2605 }
2606
2607 static int chunk_usage_filter(struct btrfs_fs_info *fs_info, u64 chunk_offset,
2608                               struct btrfs_balance_args *bargs)
2609 {
2610         struct btrfs_block_group_cache *cache;
2611         u64 chunk_used, user_thresh;
2612         int ret = 1;
2613
2614         cache = btrfs_lookup_block_group(fs_info, chunk_offset);
2615         chunk_used = btrfs_block_group_used(&cache->item);
2616
2617         user_thresh = div_factor_fine(cache->key.offset, bargs->usage);
2618         if (chunk_used < user_thresh)
2619                 ret = 0;
2620
2621         btrfs_put_block_group(cache);
2622         return ret;
2623 }
2624
2625 static int chunk_devid_filter(struct extent_buffer *leaf,
2626                               struct btrfs_chunk *chunk,
2627                               struct btrfs_balance_args *bargs)
2628 {
2629         struct btrfs_stripe *stripe;
2630         int num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
2631         int i;
2632
2633         for (i = 0; i < num_stripes; i++) {
2634                 stripe = btrfs_stripe_nr(chunk, i);
2635                 if (btrfs_stripe_devid(leaf, stripe) == bargs->devid)
2636                         return 0;
2637         }
2638
2639         return 1;
2640 }
2641
2642 /* [pstart, pend) */
2643 static int chunk_drange_filter(struct extent_buffer *leaf,
2644                                struct btrfs_chunk *chunk,
2645                                u64 chunk_offset,
2646                                struct btrfs_balance_args *bargs)
2647 {
2648         struct btrfs_stripe *stripe;
2649         int num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
2650         u64 stripe_offset;
2651         u64 stripe_length;
2652         int factor;
2653         int i;
2654
2655         if (!(bargs->flags & BTRFS_BALANCE_ARGS_DEVID))
2656                 return 0;
2657
2658         if (btrfs_chunk_type(leaf, chunk) & (BTRFS_BLOCK_GROUP_DUP |
2659              BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10))
2660                 factor = 2;
2661         else
2662                 factor = 1;
2663         factor = num_stripes / factor;
2664
2665         for (i = 0; i < num_stripes; i++) {
2666                 stripe = btrfs_stripe_nr(chunk, i);
2667                 if (btrfs_stripe_devid(leaf, stripe) != bargs->devid)
2668                         continue;
2669
2670                 stripe_offset = btrfs_stripe_offset(leaf, stripe);
2671                 stripe_length = btrfs_chunk_length(leaf, chunk);
2672                 do_div(stripe_length, factor);
2673
2674                 if (stripe_offset < bargs->pend &&
2675                     stripe_offset + stripe_length > bargs->pstart)
2676                         return 0;
2677         }
2678
2679         return 1;
2680 }
2681
2682 /* [vstart, vend) */
2683 static int chunk_vrange_filter(struct extent_buffer *leaf,
2684                                struct btrfs_chunk *chunk,
2685                                u64 chunk_offset,
2686                                struct btrfs_balance_args *bargs)
2687 {
2688         if (chunk_offset < bargs->vend &&
2689             chunk_offset + btrfs_chunk_length(leaf, chunk) > bargs->vstart)
2690                 /* at least part of the chunk is inside this vrange */
2691                 return 0;
2692
2693         return 1;
2694 }
2695
2696 static int chunk_soft_convert_filter(u64 chunk_type,
2697                                      struct btrfs_balance_args *bargs)
2698 {
2699         if (!(bargs->flags & BTRFS_BALANCE_ARGS_CONVERT))
2700                 return 0;
2701
2702         chunk_type = chunk_to_extended(chunk_type) &
2703                                 BTRFS_EXTENDED_PROFILE_MASK;
2704
2705         if (bargs->target == chunk_type)
2706                 return 1;
2707
2708         return 0;
2709 }
2710
2711 static int should_balance_chunk(struct btrfs_root *root,
2712                                 struct extent_buffer *leaf,
2713                                 struct btrfs_chunk *chunk, u64 chunk_offset)
2714 {
2715         struct btrfs_balance_control *bctl = root->fs_info->balance_ctl;
2716         struct btrfs_balance_args *bargs = NULL;
2717         u64 chunk_type = btrfs_chunk_type(leaf, chunk);
2718
2719         /* type filter */
2720         if (!((chunk_type & BTRFS_BLOCK_GROUP_TYPE_MASK) &
2721               (bctl->flags & BTRFS_BALANCE_TYPE_MASK))) {
2722                 return 0;
2723         }
2724
2725         if (chunk_type & BTRFS_BLOCK_GROUP_DATA)
2726                 bargs = &bctl->data;
2727         else if (chunk_type & BTRFS_BLOCK_GROUP_SYSTEM)
2728                 bargs = &bctl->sys;
2729         else if (chunk_type & BTRFS_BLOCK_GROUP_METADATA)
2730                 bargs = &bctl->meta;
2731
2732         /* profiles filter */
2733         if ((bargs->flags & BTRFS_BALANCE_ARGS_PROFILES) &&
2734             chunk_profiles_filter(chunk_type, bargs)) {
2735                 return 0;
2736         }
2737
2738         /* usage filter */
2739         if ((bargs->flags & BTRFS_BALANCE_ARGS_USAGE) &&
2740             chunk_usage_filter(bctl->fs_info, chunk_offset, bargs)) {
2741                 return 0;
2742         }
2743
2744         /* devid filter */
2745         if ((bargs->flags & BTRFS_BALANCE_ARGS_DEVID) &&
2746             chunk_devid_filter(leaf, chunk, bargs)) {
2747                 return 0;
2748         }
2749
2750         /* drange filter, makes sense only with devid filter */
2751         if ((bargs->flags & BTRFS_BALANCE_ARGS_DRANGE) &&
2752             chunk_drange_filter(leaf, chunk, chunk_offset, bargs)) {
2753                 return 0;
2754         }
2755
2756         /* vrange filter */
2757         if ((bargs->flags & BTRFS_BALANCE_ARGS_VRANGE) &&
2758             chunk_vrange_filter(leaf, chunk, chunk_offset, bargs)) {
2759                 return 0;
2760         }
2761
2762         /* soft profile changing mode */
2763         if ((bargs->flags & BTRFS_BALANCE_ARGS_SOFT) &&
2764             chunk_soft_convert_filter(chunk_type, bargs)) {
2765                 return 0;
2766         }
2767
2768         return 1;
2769 }
2770
2771 static int __btrfs_balance(struct btrfs_fs_info *fs_info)
2772 {
2773         struct btrfs_balance_control *bctl = fs_info->balance_ctl;
2774         struct btrfs_root *chunk_root = fs_info->chunk_root;
2775         struct btrfs_root *dev_root = fs_info->dev_root;
2776         struct list_head *devices;
2777         struct btrfs_device *device;
2778         u64 old_size;
2779         u64 size_to_free;
2780         struct btrfs_chunk *chunk;
2781         struct btrfs_path *path;
2782         struct btrfs_key key;
2783         struct btrfs_key found_key;
2784         struct btrfs_trans_handle *trans;
2785         struct extent_buffer *leaf;
2786         int slot;
2787         int ret;
2788         int enospc_errors = 0;
2789         bool counting = true;
2790
2791         /* step one make some room on all the devices */
2792         devices = &fs_info->fs_devices->devices;
2793         list_for_each_entry(device, devices, dev_list) {
2794                 old_size = device->total_bytes;
2795                 size_to_free = div_factor(old_size, 1);
2796                 size_to_free = min(size_to_free, (u64)1 * 1024 * 1024);
2797                 if (!device->writeable ||
2798                     device->total_bytes - device->bytes_used > size_to_free ||
2799                     device->is_tgtdev_for_dev_replace)
2800                         continue;
2801
2802                 ret = btrfs_shrink_device(device, old_size - size_to_free);
2803                 if (ret == -ENOSPC)
2804                         break;
2805                 BUG_ON(ret);
2806
2807                 trans = btrfs_start_transaction(dev_root, 0);
2808                 BUG_ON(IS_ERR(trans));
2809
2810                 ret = btrfs_grow_device(trans, device, old_size);
2811                 BUG_ON(ret);
2812
2813                 btrfs_end_transaction(trans, dev_root);
2814         }
2815
2816         /* step two, relocate all the chunks */
2817         path = btrfs_alloc_path();
2818         if (!path) {
2819                 ret = -ENOMEM;
2820                 goto error;
2821         }
2822
2823         /* zero out stat counters */
2824         spin_lock(&fs_info->balance_lock);
2825         memset(&bctl->stat, 0, sizeof(bctl->stat));
2826         spin_unlock(&fs_info->balance_lock);
2827 again:
2828         key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
2829         key.offset = (u64)-1;
2830         key.type = BTRFS_CHUNK_ITEM_KEY;
2831
2832         while (1) {
2833                 if ((!counting && atomic_read(&fs_info->balance_pause_req)) ||
2834                     atomic_read(&fs_info->balance_cancel_req)) {
2835                         ret = -ECANCELED;
2836                         goto error;
2837                 }
2838
2839                 ret = btrfs_search_slot(NULL, chunk_root, &key, path, 0, 0);
2840                 if (ret < 0)
2841                         goto error;
2842
2843                 /*
2844                  * this shouldn't happen, it means the last relocate
2845                  * failed
2846                  */
2847                 if (ret == 0)
2848                         BUG(); /* FIXME break ? */
2849
2850                 ret = btrfs_previous_item(chunk_root, path, 0,
2851                                           BTRFS_CHUNK_ITEM_KEY);
2852                 if (ret) {
2853                         ret = 0;
2854                         break;
2855                 }
2856
2857                 leaf = path->nodes[0];
2858                 slot = path->slots[0];
2859                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
2860
2861                 if (found_key.objectid != key.objectid)
2862                         break;
2863
2864                 /* chunk zero is special */
2865                 if (found_key.offset == 0)
2866                         break;
2867
2868                 chunk = btrfs_item_ptr(leaf, slot, struct btrfs_chunk);
2869
2870                 if (!counting) {
2871                         spin_lock(&fs_info->balance_lock);
2872                         bctl->stat.considered++;
2873                         spin_unlock(&fs_info->balance_lock);
2874                 }
2875
2876                 ret = should_balance_chunk(chunk_root, leaf, chunk,
2877                                            found_key.offset);
2878                 btrfs_release_path(path);
2879                 if (!ret)
2880                         goto loop;
2881
2882                 if (counting) {
2883                         spin_lock(&fs_info->balance_lock);
2884                         bctl->stat.expected++;
2885                         spin_unlock(&fs_info->balance_lock);
2886                         goto loop;
2887                 }
2888
2889                 ret = btrfs_relocate_chunk(chunk_root,
2890                                            chunk_root->root_key.objectid,
2891                                            found_key.objectid,
2892                                            found_key.offset);
2893                 if (ret && ret != -ENOSPC)
2894                         goto error;
2895                 if (ret == -ENOSPC) {
2896                         enospc_errors++;
2897                 } else {
2898                         spin_lock(&fs_info->balance_lock);
2899                         bctl->stat.completed++;
2900                         spin_unlock(&fs_info->balance_lock);
2901                 }
2902 loop:
2903                 key.offset = found_key.offset - 1;
2904         }
2905
2906         if (counting) {
2907                 btrfs_release_path(path);
2908                 counting = false;
2909                 goto again;
2910         }
2911 error:
2912         btrfs_free_path(path);
2913         if (enospc_errors) {
2914                 printk(KERN_INFO "btrfs: %d enospc errors during balance\n",
2915                        enospc_errors);
2916                 if (!ret)
2917                         ret = -ENOSPC;
2918         }
2919
2920         return ret;
2921 }
2922
2923 /**
2924  * alloc_profile_is_valid - see if a given profile is valid and reduced
2925  * @flags: profile to validate
2926  * @extended: if true @flags is treated as an extended profile
2927  */
2928 static int alloc_profile_is_valid(u64 flags, int extended)
2929 {
2930         u64 mask = (extended ? BTRFS_EXTENDED_PROFILE_MASK :
2931                                BTRFS_BLOCK_GROUP_PROFILE_MASK);
2932
2933         flags &= ~BTRFS_BLOCK_GROUP_TYPE_MASK;
2934
2935         /* 1) check that all other bits are zeroed */
2936         if (flags & ~mask)
2937                 return 0;
2938
2939         /* 2) see if profile is reduced */
2940         if (flags == 0)
2941                 return !extended; /* "0" is valid for usual profiles */
2942
2943         /* true if exactly one bit set */
2944         return (flags & (flags - 1)) == 0;
2945 }
2946
2947 static inline int balance_need_close(struct btrfs_fs_info *fs_info)
2948 {
2949         /* cancel requested || normal exit path */
2950         return atomic_read(&fs_info->balance_cancel_req) ||
2951                 (atomic_read(&fs_info->balance_pause_req) == 0 &&
2952                  atomic_read(&fs_info->balance_cancel_req) == 0);
2953 }
2954
2955 static void __cancel_balance(struct btrfs_fs_info *fs_info)
2956 {
2957         int ret;
2958
2959         unset_balance_control(fs_info);
2960         ret = del_balance_item(fs_info->tree_root);
2961         BUG_ON(ret);
2962 }
2963
2964 void update_ioctl_balance_args(struct btrfs_fs_info *fs_info, int lock,
2965                                struct btrfs_ioctl_balance_args *bargs);
2966
2967 /*
2968  * Should be called with both balance and volume mutexes held
2969  */
2970 int btrfs_balance(struct btrfs_balance_control *bctl,
2971                   struct btrfs_ioctl_balance_args *bargs)
2972 {
2973         struct btrfs_fs_info *fs_info = bctl->fs_info;
2974         u64 allowed;
2975         int mixed = 0;
2976         int ret;
2977         u64 num_devices;
2978
2979         if (btrfs_fs_closing(fs_info) ||
2980             atomic_read(&fs_info->balance_pause_req) ||
2981             atomic_read(&fs_info->balance_cancel_req)) {
2982                 ret = -EINVAL;
2983                 goto out;
2984         }
2985
2986         allowed = btrfs_super_incompat_flags(fs_info->super_copy);
2987         if (allowed & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS)
2988                 mixed = 1;
2989
2990         /*
2991          * In case of mixed groups both data and meta should be picked,
2992          * and identical options should be given for both of them.
2993          */
2994         allowed = BTRFS_BALANCE_DATA | BTRFS_BALANCE_METADATA;
2995         if (mixed && (bctl->flags & allowed)) {
2996                 if (!(bctl->flags & BTRFS_BALANCE_DATA) ||
2997                     !(bctl->flags & BTRFS_BALANCE_METADATA) ||
2998                     memcmp(&bctl->data, &bctl->meta, sizeof(bctl->data))) {
2999                         printk(KERN_ERR "btrfs: with mixed groups data and "
3000                                "metadata balance options must be the same\n");
3001                         ret = -EINVAL;
3002                         goto out;
3003                 }
3004         }
3005
3006         num_devices = fs_info->fs_devices->num_devices;
3007         btrfs_dev_replace_lock(&fs_info->dev_replace);
3008         if (btrfs_dev_replace_is_ongoing(&fs_info->dev_replace)) {
3009                 BUG_ON(num_devices < 1);
3010                 num_devices--;
3011         }
3012         btrfs_dev_replace_unlock(&fs_info->dev_replace);
3013         allowed = BTRFS_AVAIL_ALLOC_BIT_SINGLE;
3014         if (num_devices == 1)
3015                 allowed |= BTRFS_BLOCK_GROUP_DUP;
3016         else if (num_devices < 4)
3017                 allowed |= (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID1);
3018         else
3019                 allowed |= (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID1 |
3020                                 BTRFS_BLOCK_GROUP_RAID10);
3021
3022         if ((bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
3023             (!alloc_profile_is_valid(bctl->data.target, 1) ||
3024              (bctl->data.target & ~allowed))) {
3025                 printk(KERN_ERR "btrfs: unable to start balance with target "
3026                        "data profile %llu\n",
3027                        (unsigned long long)bctl->data.target);
3028                 ret = -EINVAL;
3029                 goto out;
3030         }
3031         if ((bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
3032             (!alloc_profile_is_valid(bctl->meta.target, 1) ||
3033              (bctl->meta.target & ~allowed))) {
3034                 printk(KERN_ERR "btrfs: unable to start balance with target "
3035                        "metadata profile %llu\n",
3036                        (unsigned long long)bctl->meta.target);
3037                 ret = -EINVAL;
3038                 goto out;
3039         }
3040         if ((bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
3041             (!alloc_profile_is_valid(bctl->sys.target, 1) ||
3042              (bctl->sys.target & ~allowed))) {
3043                 printk(KERN_ERR "btrfs: unable to start balance with target "
3044                        "system profile %llu\n",
3045                        (unsigned long long)bctl->sys.target);
3046                 ret = -EINVAL;
3047                 goto out;
3048         }
3049
3050         /* allow dup'ed data chunks only in mixed mode */
3051         if (!mixed && (bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
3052             (bctl->data.target & BTRFS_BLOCK_GROUP_DUP)) {
3053                 printk(KERN_ERR "btrfs: dup for data is not allowed\n");
3054                 ret = -EINVAL;
3055                 goto out;
3056         }
3057
3058         /* allow to reduce meta or sys integrity only if force set */
3059         allowed = BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1 |
3060                         BTRFS_BLOCK_GROUP_RAID10;
3061         if (((bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
3062              (fs_info->avail_system_alloc_bits & allowed) &&
3063              !(bctl->sys.target & allowed)) ||
3064             ((bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
3065              (fs_info->avail_metadata_alloc_bits & allowed) &&
3066              !(bctl->meta.target & allowed))) {
3067                 if (bctl->flags & BTRFS_BALANCE_FORCE) {
3068                         printk(KERN_INFO "btrfs: force reducing metadata "
3069                                "integrity\n");
3070                 } else {
3071                         printk(KERN_ERR "btrfs: balance will reduce metadata "
3072                                "integrity, use force if you want this\n");
3073                         ret = -EINVAL;
3074                         goto out;
3075                 }
3076         }
3077
3078         if (bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3079                 int num_tolerated_disk_barrier_failures;
3080                 u64 target = bctl->sys.target;
3081
3082                 num_tolerated_disk_barrier_failures =
3083                         btrfs_calc_num_tolerated_disk_barrier_failures(fs_info);
3084                 if (num_tolerated_disk_barrier_failures > 0 &&
3085                     (target &
3086                      (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID0 |
3087                       BTRFS_AVAIL_ALLOC_BIT_SINGLE)))
3088                         num_tolerated_disk_barrier_failures = 0;
3089                 else if (num_tolerated_disk_barrier_failures > 1 &&
3090                          (target &
3091                           (BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10)))
3092                         num_tolerated_disk_barrier_failures = 1;
3093
3094                 fs_info->num_tolerated_disk_barrier_failures =
3095                         num_tolerated_disk_barrier_failures;
3096         }
3097
3098         ret = insert_balance_item(fs_info->tree_root, bctl);
3099         if (ret && ret != -EEXIST)
3100                 goto out;
3101
3102         if (!(bctl->flags & BTRFS_BALANCE_RESUME)) {
3103                 BUG_ON(ret == -EEXIST);
3104                 set_balance_control(bctl);
3105         } else {
3106                 BUG_ON(ret != -EEXIST);
3107                 spin_lock(&fs_info->balance_lock);
3108                 update_balance_args(bctl);
3109                 spin_unlock(&fs_info->balance_lock);
3110         }
3111
3112         atomic_inc(&fs_info->balance_running);
3113         mutex_unlock(&fs_info->balance_mutex);
3114
3115         ret = __btrfs_balance(fs_info);
3116
3117         mutex_lock(&fs_info->balance_mutex);
3118         atomic_dec(&fs_info->balance_running);
3119
3120         if (bargs) {
3121                 memset(bargs, 0, sizeof(*bargs));
3122                 update_ioctl_balance_args(fs_info, 0, bargs);
3123         }
3124
3125         if ((ret && ret != -ECANCELED && ret != -ENOSPC) ||
3126             balance_need_close(fs_info)) {
3127                 __cancel_balance(fs_info);
3128         }
3129
3130         if (bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3131                 fs_info->num_tolerated_disk_barrier_failures =
3132                         btrfs_calc_num_tolerated_disk_barrier_failures(fs_info);
3133         }
3134
3135         wake_up(&fs_info->balance_wait_q);
3136
3137         return ret;
3138 out:
3139         if (bctl->flags & BTRFS_BALANCE_RESUME)
3140                 __cancel_balance(fs_info);
3141         else
3142                 kfree(bctl);
3143         return ret;
3144 }
3145
3146 static int balance_kthread(void *data)
3147 {
3148         struct btrfs_fs_info *fs_info = data;
3149         int ret = 0;
3150
3151         mutex_lock(&fs_info->volume_mutex);
3152         mutex_lock(&fs_info->balance_mutex);
3153
3154         if (fs_info->balance_ctl) {
3155                 printk(KERN_INFO "btrfs: continuing balance\n");
3156                 ret = btrfs_balance(fs_info->balance_ctl, NULL);
3157         }
3158
3159         atomic_set(&fs_info->mutually_exclusive_operation_running, 0);
3160         mutex_unlock(&fs_info->balance_mutex);
3161         mutex_unlock(&fs_info->volume_mutex);
3162
3163         return ret;
3164 }
3165
3166 int btrfs_resume_balance_async(struct btrfs_fs_info *fs_info)
3167 {
3168         struct task_struct *tsk;
3169
3170         spin_lock(&fs_info->balance_lock);
3171         if (!fs_info->balance_ctl) {
3172                 spin_unlock(&fs_info->balance_lock);
3173                 return 0;
3174         }
3175         spin_unlock(&fs_info->balance_lock);
3176
3177         if (btrfs_test_opt(fs_info->tree_root, SKIP_BALANCE)) {
3178                 printk(KERN_INFO "btrfs: force skipping balance\n");
3179                 return 0;
3180         }
3181
3182         WARN_ON(atomic_xchg(&fs_info->mutually_exclusive_operation_running, 1));
3183         tsk = kthread_run(balance_kthread, fs_info, "btrfs-balance");
3184         if (IS_ERR(tsk))
3185                 return PTR_ERR(tsk);
3186
3187         return 0;
3188 }
3189
3190 int btrfs_recover_balance(struct btrfs_fs_info *fs_info)
3191 {
3192         struct btrfs_balance_control *bctl;
3193         struct btrfs_balance_item *item;
3194         struct btrfs_disk_balance_args disk_bargs;
3195         struct btrfs_path *path;
3196         struct extent_buffer *leaf;
3197         struct btrfs_key key;
3198         int ret;
3199
3200         path = btrfs_alloc_path();
3201         if (!path)
3202                 return -ENOMEM;
3203
3204         key.objectid = BTRFS_BALANCE_OBJECTID;
3205         key.type = BTRFS_BALANCE_ITEM_KEY;
3206         key.offset = 0;
3207
3208         ret = btrfs_search_slot(NULL, fs_info->tree_root, &key, path, 0, 0);
3209         if (ret < 0)
3210                 goto out;
3211         if (ret > 0) { /* ret = -ENOENT; */
3212                 ret = 0;
3213                 goto out;
3214         }
3215
3216         bctl = kzalloc(sizeof(*bctl), GFP_NOFS);
3217         if (!bctl) {
3218                 ret = -ENOMEM;
3219                 goto out;
3220         }
3221
3222         leaf = path->nodes[0];
3223         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_balance_item);
3224
3225         bctl->fs_info = fs_info;
3226         bctl->flags = btrfs_balance_flags(leaf, item);
3227         bctl->flags |= BTRFS_BALANCE_RESUME;
3228
3229         btrfs_balance_data(leaf, item, &disk_bargs);
3230         btrfs_disk_balance_args_to_cpu(&bctl->data, &disk_bargs);
3231         btrfs_balance_meta(leaf, item, &disk_bargs);
3232         btrfs_disk_balance_args_to_cpu(&bctl->meta, &disk_bargs);
3233         btrfs_balance_sys(leaf, item, &disk_bargs);
3234         btrfs_disk_balance_args_to_cpu(&bctl->sys, &disk_bargs);
3235
3236         mutex_lock(&fs_info->volume_mutex);
3237         mutex_lock(&fs_info->balance_mutex);
3238
3239         set_balance_control(bctl);
3240
3241         mutex_unlock(&fs_info->balance_mutex);
3242         mutex_unlock(&fs_info->volume_mutex);
3243 out:
3244         btrfs_free_path(path);
3245         return ret;
3246 }
3247
3248 int btrfs_pause_balance(struct btrfs_fs_info *fs_info)
3249 {
3250         int ret = 0;
3251
3252         mutex_lock(&fs_info->balance_mutex);
3253         if (!fs_info->balance_ctl) {
3254                 mutex_unlock(&fs_info->balance_mutex);
3255                 return -ENOTCONN;
3256         }
3257
3258         if (atomic_read(&fs_info->balance_running)) {
3259                 atomic_inc(&fs_info->balance_pause_req);
3260                 mutex_unlock(&fs_info->balance_mutex);
3261
3262                 wait_event(fs_info->balance_wait_q,
3263                            atomic_read(&fs_info->balance_running) == 0);
3264
3265                 mutex_lock(&fs_info->balance_mutex);
3266                 /* we are good with balance_ctl ripped off from under us */
3267                 BUG_ON(atomic_read(&fs_info->balance_running));
3268                 atomic_dec(&fs_info->balance_pause_req);
3269         } else {
3270                 ret = -ENOTCONN;
3271         }
3272
3273         mutex_unlock(&fs_info->balance_mutex);
3274         return ret;
3275 }
3276
3277 int btrfs_cancel_balance(struct btrfs_fs_info *fs_info)
3278 {
3279         mutex_lock(&fs_info->balance_mutex);
3280         if (!fs_info->balance_ctl) {
3281                 mutex_unlock(&fs_info->balance_mutex);
3282                 return -ENOTCONN;
3283         }
3284
3285         atomic_inc(&fs_info->balance_cancel_req);
3286         /*
3287          * if we are running just wait and return, balance item is
3288          * deleted in btrfs_balance in this case
3289          */
3290         if (atomic_read(&fs_info->balance_running)) {
3291                 mutex_unlock(&fs_info->balance_mutex);
3292                 wait_event(fs_info->balance_wait_q,
3293                            atomic_read(&fs_info->balance_running) == 0);
3294                 mutex_lock(&fs_info->balance_mutex);
3295         } else {
3296                 /* __cancel_balance needs volume_mutex */
3297                 mutex_unlock(&fs_info->balance_mutex);
3298                 mutex_lock(&fs_info->volume_mutex);
3299                 mutex_lock(&fs_info->balance_mutex);
3300
3301                 if (fs_info->balance_ctl)
3302                         __cancel_balance(fs_info);
3303
3304                 mutex_unlock(&fs_info->volume_mutex);
3305         }
3306
3307         BUG_ON(fs_info->balance_ctl || atomic_read(&fs_info->balance_running));
3308         atomic_dec(&fs_info->balance_cancel_req);
3309         mutex_unlock(&fs_info->balance_mutex);
3310         return 0;
3311 }
3312
3313 /*
3314  * shrinking a device means finding all of the device extents past
3315  * the new size, and then following the back refs to the chunks.
3316  * The chunk relocation code actually frees the device extent
3317  */
3318 int btrfs_shrink_device(struct btrfs_device *device, u64 new_size)
3319 {
3320         struct btrfs_trans_handle *trans;
3321         struct btrfs_root *root = device->dev_root;
3322         struct btrfs_dev_extent *dev_extent = NULL;
3323         struct btrfs_path *path;
3324         u64 length;
3325         u64 chunk_tree;
3326         u64 chunk_objectid;
3327         u64 chunk_offset;
3328         int ret;
3329         int slot;
3330         int failed = 0;
3331         bool retried = false;
3332         struct extent_buffer *l;
3333         struct btrfs_key key;
3334         struct btrfs_super_block *super_copy = root->fs_info->super_copy;
3335         u64 old_total = btrfs_super_total_bytes(super_copy);
3336         u64 old_size = device->total_bytes;
3337         u64 diff = device->total_bytes - new_size;
3338
3339         if (device->is_tgtdev_for_dev_replace)
3340                 return -EINVAL;
3341
3342         path = btrfs_alloc_path();
3343         if (!path)
3344                 return -ENOMEM;
3345
3346         path->reada = 2;
3347
3348         lock_chunks(root);
3349
3350         device->total_bytes = new_size;
3351         if (device->writeable) {
3352                 device->fs_devices->total_rw_bytes -= diff;
3353                 spin_lock(&root->fs_info->free_chunk_lock);
3354                 root->fs_info->free_chunk_space -= diff;
3355                 spin_unlock(&root->fs_info->free_chunk_lock);
3356         }
3357         unlock_chunks(root);
3358
3359 again:
3360         key.objectid = device->devid;
3361         key.offset = (u64)-1;
3362         key.type = BTRFS_DEV_EXTENT_KEY;
3363
3364         do {
3365                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3366                 if (ret < 0)
3367                         goto done;
3368
3369                 ret = btrfs_previous_item(root, path, 0, key.type);
3370                 if (ret < 0)
3371                         goto done;
3372                 if (ret) {
3373                         ret = 0;
3374                         btrfs_release_path(path);
3375                         break;
3376                 }
3377
3378                 l = path->nodes[0];
3379                 slot = path->slots[0];
3380                 btrfs_item_key_to_cpu(l, &key, path->slots[0]);
3381
3382                 if (key.objectid != device->devid) {
3383                         btrfs_release_path(path);
3384                         break;
3385                 }
3386
3387                 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
3388                 length = btrfs_dev_extent_length(l, dev_extent);
3389
3390                 if (key.offset + length <= new_size) {
3391                         btrfs_release_path(path);
3392                         break;
3393                 }
3394
3395                 chunk_tree = btrfs_dev_extent_chunk_tree(l, dev_extent);
3396                 chunk_objectid = btrfs_dev_extent_chunk_objectid(l, dev_extent);
3397                 chunk_offset = btrfs_dev_extent_chunk_offset(l, dev_extent);
3398                 btrfs_release_path(path);
3399
3400                 ret = btrfs_relocate_chunk(root, chunk_tree, chunk_objectid,
3401                                            chunk_offset);
3402                 if (ret && ret != -ENOSPC)
3403                         goto done;
3404                 if (ret == -ENOSPC)
3405                         failed++;
3406         } while (key.offset-- > 0);
3407
3408         if (failed && !retried) {
3409                 failed = 0;
3410                 retried = true;
3411                 goto again;
3412         } else if (failed && retried) {
3413                 ret = -ENOSPC;
3414                 lock_chunks(root);
3415
3416                 device->total_bytes = old_size;
3417                 if (device->writeable)
3418                         device->fs_devices->total_rw_bytes += diff;
3419                 spin_lock(&root->fs_info->free_chunk_lock);
3420                 root->fs_info->free_chunk_space += diff;
3421                 spin_unlock(&root->fs_info->free_chunk_lock);
3422                 unlock_chunks(root);
3423                 goto done;
3424         }
3425
3426         /* Shrinking succeeded, else we would be at "done". */
3427         trans = btrfs_start_transaction(root, 0);
3428         if (IS_ERR(trans)) {
3429                 ret = PTR_ERR(trans);
3430                 goto done;
3431         }
3432
3433         lock_chunks(root);
3434
3435         device->disk_total_bytes = new_size;
3436         /* Now btrfs_update_device() will change the on-disk size. */
3437         ret = btrfs_update_device(trans, device);
3438         if (ret) {
3439                 unlock_chunks(root);
3440                 btrfs_end_transaction(trans, root);
3441                 goto done;
3442         }
3443         WARN_ON(diff > old_total);
3444         btrfs_set_super_total_bytes(super_copy, old_total - diff);
3445         unlock_chunks(root);
3446         btrfs_end_transaction(trans, root);
3447 done:
3448         btrfs_free_path(path);
3449         return ret;
3450 }
3451
3452 static int btrfs_add_system_chunk(struct btrfs_root *root,
3453                            struct btrfs_key *key,
3454                            struct btrfs_chunk *chunk, int item_size)
3455 {
3456         struct btrfs_super_block *super_copy = root->fs_info->super_copy;
3457         struct btrfs_disk_key disk_key;
3458         u32 array_size;
3459         u8 *ptr;
3460
3461         array_size = btrfs_super_sys_array_size(super_copy);
3462         if (array_size + item_size > BTRFS_SYSTEM_CHUNK_ARRAY_SIZE)
3463                 return -EFBIG;
3464
3465         ptr = super_copy->sys_chunk_array + array_size;
3466         btrfs_cpu_key_to_disk(&disk_key, key);
3467         memcpy(ptr, &disk_key, sizeof(disk_key));
3468         ptr += sizeof(disk_key);
3469         memcpy(ptr, chunk, item_size);
3470         item_size += sizeof(disk_key);
3471         btrfs_set_super_sys_array_size(super_copy, array_size + item_size);
3472         return 0;
3473 }
3474
3475 /*
3476  * sort the devices in descending order by max_avail, total_avail
3477  */
3478 static int btrfs_cmp_device_info(const void *a, const void *b)
3479 {
3480         const struct btrfs_device_info *di_a = a;
3481         const struct btrfs_device_info *di_b = b;
3482
3483         if (di_a->max_avail > di_b->max_avail)
3484                 return -1;
3485         if (di_a->max_avail < di_b->max_avail)
3486                 return 1;
3487         if (di_a->total_avail > di_b->total_avail)
3488                 return -1;
3489         if (di_a->total_avail < di_b->total_avail)
3490                 return 1;
3491         return 0;
3492 }
3493
3494 static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
3495                                struct btrfs_root *extent_root,
3496                                struct map_lookup **map_ret,
3497                                u64 *num_bytes_out, u64 *stripe_size_out,
3498                                u64 start, u64 type)
3499 {
3500         struct btrfs_fs_info *info = extent_root->fs_info;
3501         struct btrfs_fs_devices *fs_devices = info->fs_devices;
3502         struct list_head *cur;
3503         struct map_lookup *map = NULL;
3504         struct extent_map_tree *em_tree;
3505         struct extent_map *em;
3506         struct btrfs_device_info *devices_info = NULL;
3507         u64 total_avail;
3508         int num_stripes;        /* total number of stripes to allocate */
3509         int sub_stripes;        /* sub_stripes info for map */
3510         int dev_stripes;        /* stripes per dev */
3511         int devs_max;           /* max devs to use */
3512         int devs_min;           /* min devs needed */
3513         int devs_increment;     /* ndevs has to be a multiple of this */
3514         int ncopies;            /* how many copies to data has */
3515         int ret;
3516         u64 max_stripe_size;
3517         u64 max_chunk_size;
3518         u64 stripe_size;
3519         u64 num_bytes;
3520         int ndevs;
3521         int i;
3522         int j;
3523
3524         BUG_ON(!alloc_profile_is_valid(type, 0));
3525
3526         if (list_empty(&fs_devices->alloc_list))
3527                 return -ENOSPC;
3528
3529         sub_stripes = 1;
3530         dev_stripes = 1;
3531         devs_increment = 1;
3532         ncopies = 1;
3533         devs_max = 0;   /* 0 == as many as possible */
3534         devs_min = 1;
3535
3536         /*
3537          * define the properties of each RAID type.
3538          * FIXME: move this to a global table and use it in all RAID
3539          * calculation code
3540          */
3541         if (type & (BTRFS_BLOCK_GROUP_DUP)) {
3542                 dev_stripes = 2;
3543                 ncopies = 2;
3544                 devs_max = 1;
3545         } else if (type & (BTRFS_BLOCK_GROUP_RAID0)) {
3546                 devs_min = 2;
3547         } else if (type & (BTRFS_BLOCK_GROUP_RAID1)) {
3548                 devs_increment = 2;
3549                 ncopies = 2;
3550                 devs_max = 2;
3551                 devs_min = 2;
3552         } else if (type & (BTRFS_BLOCK_GROUP_RAID10)) {
3553                 sub_stripes = 2;
3554                 devs_increment = 2;
3555                 ncopies = 2;
3556                 devs_min = 4;
3557         } else {
3558                 devs_max = 1;
3559         }
3560
3561         if (type & BTRFS_BLOCK_GROUP_DATA) {
3562                 max_stripe_size = 1024 * 1024 * 1024;
3563                 max_chunk_size = 10 * max_stripe_size;
3564         } else if (type & BTRFS_BLOCK_GROUP_METADATA) {
3565                 /* for larger filesystems, use larger metadata chunks */
3566                 if (fs_devices->total_rw_bytes > 50ULL * 1024 * 1024 * 1024)
3567                         max_stripe_size = 1024 * 1024 * 1024;
3568                 else
3569                         max_stripe_size = 256 * 1024 * 1024;
3570                 max_chunk_size = max_stripe_size;
3571         } else if (type & BTRFS_BLOCK_GROUP_SYSTEM) {
3572                 max_stripe_size = 32 * 1024 * 1024;
3573                 max_chunk_size = 2 * max_stripe_size;
3574         } else {
3575                 printk(KERN_ERR "btrfs: invalid chunk type 0x%llx requested\n",
3576                        type);
3577                 BUG_ON(1);
3578         }
3579
3580         /* we don't want a chunk larger than 10% of writeable space */
3581         max_chunk_size = min(div_factor(fs_devices->total_rw_bytes, 1),
3582                              max_chunk_size);
3583
3584         devices_info = kzalloc(sizeof(*devices_info) * fs_devices->rw_devices,
3585                                GFP_NOFS);
3586         if (!devices_info)
3587                 return -ENOMEM;
3588
3589         cur = fs_devices->alloc_list.next;
3590
3591         /*
3592          * in the first pass through the devices list, we gather information
3593          * about the available holes on each device.
3594          */
3595         ndevs = 0;
3596         while (cur != &fs_devices->alloc_list) {
3597                 struct btrfs_device *device;
3598                 u64 max_avail;
3599                 u64 dev_offset;
3600
3601                 device = list_entry(cur, struct btrfs_device, dev_alloc_list);
3602
3603                 cur = cur->next;
3604
3605                 if (!device->writeable) {
3606                         WARN(1, KERN_ERR
3607                                "btrfs: read-only device in alloc_list\n");
3608                         continue;
3609                 }
3610
3611                 if (!device->in_fs_metadata ||
3612                     device->is_tgtdev_for_dev_replace)
3613                         continue;
3614
3615                 if (device->total_bytes > device->bytes_used)
3616                         total_avail = device->total_bytes - device->bytes_used;
3617                 else
3618                         total_avail = 0;
3619
3620                 /* If there is no space on this device, skip it. */
3621                 if (total_avail == 0)
3622                         continue;
3623
3624                 ret = find_free_dev_extent(device,
3625                                            max_stripe_size * dev_stripes,
3626                                            &dev_offset, &max_avail);
3627                 if (ret && ret != -ENOSPC)
3628                         goto error;
3629
3630                 if (ret == 0)
3631                         max_avail = max_stripe_size * dev_stripes;
3632
3633                 if (max_avail < BTRFS_STRIPE_LEN * dev_stripes)
3634                         continue;
3635
3636                 devices_info[ndevs].dev_offset = dev_offset;
3637                 devices_info[ndevs].max_avail = max_avail;
3638                 devices_info[ndevs].total_avail = total_avail;
3639                 devices_info[ndevs].dev = device;
3640                 ++ndevs;
3641                 WARN_ON(ndevs > fs_devices->rw_devices);
3642         }
3643
3644         /*
3645          * now sort the devices by hole size / available space
3646          */
3647         sort(devices_info, ndevs, sizeof(struct btrfs_device_info),
3648              btrfs_cmp_device_info, NULL);
3649
3650         /* round down to number of usable stripes */
3651         ndevs -= ndevs % devs_increment;
3652
3653         if (ndevs < devs_increment * sub_stripes || ndevs < devs_min) {
3654                 ret = -ENOSPC;
3655                 goto error;
3656         }
3657
3658         if (devs_max && ndevs > devs_max)
3659                 ndevs = devs_max;
3660         /*
3661          * the primary goal is to maximize the number of stripes, so use as many
3662          * devices as possible, even if the stripes are not maximum sized.
3663          */
3664         stripe_size = devices_info[ndevs-1].max_avail;
3665         num_stripes = ndevs * dev_stripes;
3666
3667         if (stripe_size * ndevs > max_chunk_size * ncopies) {
3668                 stripe_size = max_chunk_size * ncopies;
3669                 do_div(stripe_size, ndevs);
3670         }
3671
3672         do_div(stripe_size, dev_stripes);
3673
3674         /* align to BTRFS_STRIPE_LEN */
3675         do_div(stripe_size, BTRFS_STRIPE_LEN);
3676         stripe_size *= BTRFS_STRIPE_LEN;
3677
3678         map = kmalloc(map_lookup_size(num_stripes), GFP_NOFS);
3679         if (!map) {
3680                 ret = -ENOMEM;
3681                 goto error;
3682         }
3683         map->num_stripes = num_stripes;
3684
3685         for (i = 0; i < ndevs; ++i) {
3686                 for (j = 0; j < dev_stripes; ++j) {
3687                         int s = i * dev_stripes + j;
3688                         map->stripes[s].dev = devices_info[i].dev;
3689                         map->stripes[s].physical = devices_info[i].dev_offset +
3690                                                    j * stripe_size;
3691                 }
3692         }
3693         map->sector_size = extent_root->sectorsize;
3694         map->stripe_len = BTRFS_STRIPE_LEN;
3695         map->io_align = BTRFS_STRIPE_LEN;
3696         map->io_width = BTRFS_STRIPE_LEN;
3697         map->type = type;
3698         map->sub_stripes = sub_stripes;
3699
3700         *map_ret = map;
3701         num_bytes = stripe_size * (num_stripes / ncopies);
3702
3703         *stripe_size_out = stripe_size;
3704         *num_bytes_out = num_bytes;
3705
3706         trace_btrfs_chunk_alloc(info->chunk_root, map, start, num_bytes);
3707
3708         em = alloc_extent_map();
3709         if (!em) {
3710                 ret = -ENOMEM;
3711                 goto error;
3712         }
3713         em->bdev = (struct block_device *)map;
3714         em->start = start;
3715         em->len = num_bytes;
3716         em->block_start = 0;
3717         em->block_len = em->len;
3718
3719         em_tree = &extent_root->fs_info->mapping_tree.map_tree;
3720         write_lock(&em_tree->lock);
3721         ret = add_extent_mapping(em_tree, em);
3722         write_unlock(&em_tree->lock);
3723         free_extent_map(em);
3724         if (ret)
3725                 goto error;
3726
3727         ret = btrfs_make_block_group(trans, extent_root, 0, type,
3728                                      BTRFS_FIRST_CHUNK_TREE_OBJECTID,
3729                                      start, num_bytes);
3730         if (ret)
3731                 goto error;
3732
3733         for (i = 0; i < map->num_stripes; ++i) {
3734                 struct btrfs_device *device;
3735                 u64 dev_offset;
3736
3737                 device = map->stripes[i].dev;
3738                 dev_offset = map->stripes[i].physical;
3739
3740                 ret = btrfs_alloc_dev_extent(trans, device,
3741                                 info->chunk_root->root_key.objectid,
3742                                 BTRFS_FIRST_CHUNK_TREE_OBJECTID,
3743                                 start, dev_offset, stripe_size);
3744                 if (ret) {
3745                         btrfs_abort_transaction(trans, extent_root, ret);
3746                         goto error;
3747                 }
3748         }
3749
3750         kfree(devices_info);
3751         return 0;
3752
3753 error:
3754         kfree(map);
3755         kfree(devices_info);
3756         return ret;
3757 }
3758
3759 static int __finish_chunk_alloc(struct btrfs_trans_handle *trans,
3760                                 struct btrfs_root *extent_root,
3761                                 struct map_lookup *map, u64 chunk_offset,
3762                                 u64 chunk_size, u64 stripe_size)
3763 {
3764         u64 dev_offset;
3765         struct btrfs_key key;
3766         struct btrfs_root *chunk_root = extent_root->fs_info->chunk_root;
3767         struct btrfs_device *device;
3768         struct btrfs_chunk *chunk;
3769         struct btrfs_stripe *stripe;
3770         size_t item_size = btrfs_chunk_item_size(map->num_stripes);
3771         int index = 0;
3772         int ret;
3773
3774         chunk = kzalloc(item_size, GFP_NOFS);
3775         if (!chunk)
3776                 return -ENOMEM;
3777
3778         index = 0;
3779         while (index < map->num_stripes) {
3780                 device = map->stripes[index].dev;
3781                 device->bytes_used += stripe_size;
3782                 ret = btrfs_update_device(trans, device);
3783                 if (ret)
3784                         goto out_free;
3785                 index++;
3786         }
3787
3788         spin_lock(&extent_root->fs_info->free_chunk_lock);
3789         extent_root->fs_info->free_chunk_space -= (stripe_size *
3790                                                    map->num_stripes);
3791         spin_unlock(&extent_root->fs_info->free_chunk_lock);
3792
3793         index = 0;
3794         stripe = &chunk->stripe;
3795         while (index < map->num_stripes) {
3796                 device = map->stripes[index].dev;
3797                 dev_offset = map->stripes[index].physical;
3798
3799                 btrfs_set_stack_stripe_devid(stripe, device->devid);
3800                 btrfs_set_stack_stripe_offset(stripe, dev_offset);
3801                 memcpy(stripe->dev_uuid, device->uuid, BTRFS_UUID_SIZE);
3802                 stripe++;
3803                 index++;
3804         }
3805
3806         btrfs_set_stack_chunk_length(chunk, chunk_size);
3807         btrfs_set_stack_chunk_owner(chunk, extent_root->root_key.objectid);
3808         btrfs_set_stack_chunk_stripe_len(chunk, map->stripe_len);
3809         btrfs_set_stack_chunk_type(chunk, map->type);
3810         btrfs_set_stack_chunk_num_stripes(chunk, map->num_stripes);
3811         btrfs_set_stack_chunk_io_align(chunk, map->stripe_len);
3812         btrfs_set_stack_chunk_io_width(chunk, map->stripe_len);
3813         btrfs_set_stack_chunk_sector_size(chunk, extent_root->sectorsize);
3814         btrfs_set_stack_chunk_sub_stripes(chunk, map->sub_stripes);
3815
3816         key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
3817         key.type = BTRFS_CHUNK_ITEM_KEY;
3818         key.offset = chunk_offset;
3819
3820         ret = btrfs_insert_item(trans, chunk_root, &key, chunk, item_size);
3821
3822         if (ret == 0 && map->type & BTRFS_BLOCK_GROUP_SYSTEM) {
3823                 /*
3824                  * TODO: Cleanup of inserted chunk root in case of
3825                  * failure.
3826                  */
3827                 ret = btrfs_add_system_chunk(chunk_root, &key, chunk,
3828                                              item_size);
3829         }
3830
3831 out_free:
3832         kfree(chunk);
3833         return ret;
3834 }
3835
3836 /*
3837  * Chunk allocation falls into two parts. The first part does works
3838  * that make the new allocated chunk useable, but not do any operation
3839  * that modifies the chunk tree. The second part does the works that
3840  * require modifying the chunk tree. This division is important for the
3841  * bootstrap process of adding storage to a seed btrfs.
3842  */
3843 int btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
3844                       struct btrfs_root *extent_root, u64 type)
3845 {
3846         u64 chunk_offset;
3847         u64 chunk_size;
3848         u64 stripe_size;
3849         struct map_lookup *map;
3850         struct btrfs_root *chunk_root = extent_root->fs_info->chunk_root;
3851         int ret;
3852
3853         ret = find_next_chunk(chunk_root, BTRFS_FIRST_CHUNK_TREE_OBJECTID,
3854                               &chunk_offset);
3855         if (ret)
3856                 return ret;
3857
3858         ret = __btrfs_alloc_chunk(trans, extent_root, &map, &chunk_size,
3859                                   &stripe_size, chunk_offset, type);
3860         if (ret)
3861                 return ret;
3862
3863         ret = __finish_chunk_alloc(trans, extent_root, map, chunk_offset,
3864                                    chunk_size, stripe_size);
3865         if (ret)
3866                 return ret;
3867         return 0;
3868 }
3869
3870 static noinline int init_first_rw_device(struct btrfs_trans_handle *trans,
3871                                          struct btrfs_root *root,
3872                                          struct btrfs_device *device)
3873 {
3874         u64 chunk_offset;
3875         u64 sys_chunk_offset;
3876         u64 chunk_size;
3877         u64 sys_chunk_size;
3878         u64 stripe_size;
3879         u64 sys_stripe_size;
3880         u64 alloc_profile;
3881         struct map_lookup *map;
3882         struct map_lookup *sys_map;
3883         struct btrfs_fs_info *fs_info = root->fs_info;
3884         struct btrfs_root *extent_root = fs_info->extent_root;
3885         int ret;
3886
3887         ret = find_next_chunk(fs_info->chunk_root,
3888                               BTRFS_FIRST_CHUNK_TREE_OBJECTID, &chunk_offset);
3889         if (ret)
3890                 return ret;
3891
3892         alloc_profile = BTRFS_BLOCK_GROUP_METADATA |
3893                                 fs_info->avail_metadata_alloc_bits;
3894         alloc_profile = btrfs_reduce_alloc_profile(root, alloc_profile);
3895
3896         ret = __btrfs_alloc_chunk(trans, extent_root, &map, &chunk_size,
3897                                   &stripe_size, chunk_offset, alloc_profile);
3898         if (ret)
3899                 return ret;
3900
3901         sys_chunk_offset = chunk_offset + chunk_size;
3902
3903         alloc_profile = BTRFS_BLOCK_GROUP_SYSTEM |
3904                                 fs_info->avail_system_alloc_bits;
3905         alloc_profile = btrfs_reduce_alloc_profile(root, alloc_profile);
3906
3907         ret = __btrfs_alloc_chunk(trans, extent_root, &sys_map,
3908                                   &sys_chunk_size, &sys_stripe_size,
3909                                   sys_chunk_offset, alloc_profile);
3910         if (ret) {
3911                 btrfs_abort_transaction(trans, root, ret);
3912                 goto out;
3913         }
3914
3915         ret = btrfs_add_device(trans, fs_info->chunk_root, device);
3916         if (ret) {
3917                 btrfs_abort_transaction(trans, root, ret);
3918                 goto out;
3919         }
3920
3921         /*
3922          * Modifying chunk tree needs allocating new blocks from both
3923          * system block group and metadata block group. So we only can
3924          * do operations require modifying the chunk tree after both
3925          * block groups were created.
3926          */
3927         ret = __finish_chunk_alloc(trans, extent_root, map, chunk_offset,
3928                                    chunk_size, stripe_size);
3929         if (ret) {
3930                 btrfs_abort_transaction(trans, root, ret);
3931                 goto out;
3932         }
3933
3934         ret = __finish_chunk_alloc(trans, extent_root, sys_map,
3935                                    sys_chunk_offset, sys_chunk_size,
3936                                    sys_stripe_size);
3937         if (ret)
3938                 btrfs_abort_transaction(trans, root, ret);
3939
3940 out:
3941
3942         return ret;
3943 }
3944
3945 int btrfs_chunk_readonly(struct btrfs_root *root, u64 chunk_offset)
3946 {
3947         struct extent_map *em;
3948         struct map_lookup *map;
3949         struct btrfs_mapping_tree *map_tree = &root->fs_info->mapping_tree;
3950         int readonly = 0;
3951         int i;
3952
3953         read_lock(&map_tree->map_tree.lock);
3954         em = lookup_extent_mapping(&map_tree->map_tree, chunk_offset, 1);
3955         read_unlock(&map_tree->map_tree.lock);
3956         if (!em)
3957                 return 1;
3958
3959         if (btrfs_test_opt(root, DEGRADED)) {
3960                 free_extent_map(em);
3961                 return 0;
3962         }
3963
3964         map = (struct map_lookup *)em->bdev;
3965         for (i = 0; i < map->num_stripes; i++) {
3966                 if (!map->stripes[i].dev->writeable) {
3967                         readonly = 1;
3968                         break;
3969                 }
3970         }
3971         free_extent_map(em);
3972         return readonly;
3973 }
3974
3975 void btrfs_mapping_init(struct btrfs_mapping_tree *tree)
3976 {
3977         extent_map_tree_init(&tree->map_tree);
3978 }
3979
3980 void btrfs_mapping_tree_free(struct btrfs_mapping_tree *tree)
3981 {
3982         struct extent_map *em;
3983
3984         while (1) {
3985                 write_lock(&tree->map_tree.lock);
3986                 em = lookup_extent_mapping(&tree->map_tree, 0, (u64)-1);
3987                 if (em)
3988                         remove_extent_mapping(&tree->map_tree, em);
3989                 write_unlock(&tree->map_tree.lock);
3990                 if (!em)
3991                         break;
3992                 kfree(em->bdev);
3993                 /* once for us */
3994                 free_extent_map(em);
3995                 /* once for the tree */
3996                 free_extent_map(em);
3997         }
3998 }
3999
4000 int btrfs_num_copies(struct btrfs_fs_info *fs_info, u64 logical, u64 len)
4001 {
4002         struct btrfs_mapping_tree *map_tree = &fs_info->mapping_tree;
4003         struct extent_map *em;
4004         struct map_lookup *map;
4005         struct extent_map_tree *em_tree = &map_tree->map_tree;
4006         int ret;
4007
4008         read_lock(&em_tree->lock);
4009         em = lookup_extent_mapping(em_tree, logical, len);
4010         read_unlock(&em_tree->lock);
4011         BUG_ON(!em);
4012
4013         BUG_ON(em->start > logical || em->start + em->len < logical);
4014         map = (struct map_lookup *)em->bdev;
4015         if (map->type & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1))
4016                 ret = map->num_stripes;
4017         else if (map->type & BTRFS_BLOCK_GROUP_RAID10)
4018                 ret = map->sub_stripes;
4019         else
4020                 ret = 1;
4021         free_extent_map(em);
4022
4023         btrfs_dev_replace_lock(&fs_info->dev_replace);
4024         if (btrfs_dev_replace_is_ongoing(&fs_info->dev_replace))
4025                 ret++;
4026         btrfs_dev_replace_unlock(&fs_info->dev_replace);
4027
4028         return ret;
4029 }
4030
4031 static int find_live_mirror(struct btrfs_fs_info *fs_info,
4032                             struct map_lookup *map, int first, int num,
4033                             int optimal, int dev_replace_is_ongoing)
4034 {
4035         int i;
4036         int tolerance;
4037         struct btrfs_device *srcdev;
4038
4039         if (dev_replace_is_ongoing &&
4040             fs_info->dev_replace.cont_reading_from_srcdev_mode ==
4041              BTRFS_DEV_REPLACE_ITEM_CONT_READING_FROM_SRCDEV_MODE_AVOID)
4042                 srcdev = fs_info->dev_replace.srcdev;
4043         else
4044                 srcdev = NULL;
4045
4046         /*
4047          * try to avoid the drive that is the source drive for a
4048          * dev-replace procedure, only choose it if no other non-missing
4049          * mirror is available
4050          */
4051         for (tolerance = 0; tolerance < 2; tolerance++) {
4052                 if (map->stripes[optimal].dev->bdev &&
4053                     (tolerance || map->stripes[optimal].dev != srcdev))
4054                         return optimal;
4055                 for (i = first; i < first + num; i++) {
4056                         if (map->stripes[i].dev->bdev &&
4057                             (tolerance || map->stripes[i].dev != srcdev))
4058                                 return i;
4059                 }
4060         }
4061
4062         /* we couldn't find one that doesn't fail.  Just return something
4063          * and the io error handling code will clean up eventually
4064          */
4065         return optimal;
4066 }
4067
4068 static int __btrfs_map_block(struct btrfs_fs_info *fs_info, int rw,
4069                              u64 logical, u64 *length,
4070                              struct btrfs_bio **bbio_ret,
4071                              int mirror_num)
4072 {
4073         struct extent_map *em;
4074         struct map_lookup *map;
4075         struct btrfs_mapping_tree *map_tree = &fs_info->mapping_tree;
4076         struct extent_map_tree *em_tree = &map_tree->map_tree;
4077         u64 offset;
4078         u64 stripe_offset;
4079         u64 stripe_end_offset;
4080         u64 stripe_nr;
4081         u64 stripe_nr_orig;
4082         u64 stripe_nr_end;
4083         int stripe_index;
4084         int i;
4085         int ret = 0;
4086         int num_stripes;
4087         int max_errors = 0;
4088         struct btrfs_bio *bbio = NULL;
4089         struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
4090         int dev_replace_is_ongoing = 0;
4091         int num_alloc_stripes;
4092         int patch_the_first_stripe_for_dev_replace = 0;
4093         u64 physical_to_patch_in_first_stripe = 0;
4094
4095         read_lock(&em_tree->lock);
4096         em = lookup_extent_mapping(em_tree, logical, *length);
4097         read_unlock(&em_tree->lock);
4098
4099         if (!em) {
4100                 printk(KERN_CRIT "btrfs: unable to find logical %llu len %llu\n",
4101                        (unsigned long long)logical,
4102                        (unsigned long long)*length);
4103                 BUG();
4104         }
4105
4106         BUG_ON(em->start > logical || em->start + em->len < logical);
4107         map = (struct map_lookup *)em->bdev;
4108         offset = logical - em->start;
4109
4110         stripe_nr = offset;
4111         /*
4112          * stripe_nr counts the total number of stripes we have to stride
4113          * to get to this block
4114          */
4115         do_div(stripe_nr, map->stripe_len);
4116
4117         stripe_offset = stripe_nr * map->stripe_len;
4118         BUG_ON(offset < stripe_offset);
4119
4120         /* stripe_offset is the offset of this block in its stripe*/
4121         stripe_offset = offset - stripe_offset;
4122
4123         if (rw & REQ_DISCARD)
4124                 *length = min_t(u64, em->len - offset, *length);
4125         else if (map->type & BTRFS_BLOCK_GROUP_PROFILE_MASK) {
4126                 /* we limit the length of each bio to what fits in a stripe */
4127                 *length = min_t(u64, em->len - offset,
4128                                 map->stripe_len - stripe_offset);
4129         } else {
4130                 *length = em->len - offset;
4131         }
4132
4133         if (!bbio_ret)
4134                 goto out;
4135
4136         btrfs_dev_replace_lock(dev_replace);
4137         dev_replace_is_ongoing = btrfs_dev_replace_is_ongoing(dev_replace);
4138         if (!dev_replace_is_ongoing)
4139                 btrfs_dev_replace_unlock(dev_replace);
4140
4141         if (dev_replace_is_ongoing && mirror_num == map->num_stripes + 1 &&
4142             !(rw & (REQ_WRITE | REQ_DISCARD | REQ_GET_READ_MIRRORS)) &&
4143             dev_replace->tgtdev != NULL) {
4144                 /*
4145                  * in dev-replace case, for repair case (that's the only
4146                  * case where the mirror is selected explicitly when
4147                  * calling btrfs_map_block), blocks left of the left cursor
4148                  * can also be read from the target drive.
4149                  * For REQ_GET_READ_MIRRORS, the target drive is added as
4150                  * the last one to the array of stripes. For READ, it also
4151                  * needs to be supported using the same mirror number.
4152                  * If the requested block is not left of the left cursor,
4153                  * EIO is returned. This can happen because btrfs_num_copies()
4154                  * returns one more in the dev-replace case.
4155                  */
4156                 u64 tmp_length = *length;
4157                 struct btrfs_bio *tmp_bbio = NULL;
4158                 int tmp_num_stripes;
4159                 u64 srcdev_devid = dev_replace->srcdev->devid;
4160                 int index_srcdev = 0;
4161                 int found = 0;
4162                 u64 physical_of_found = 0;
4163
4164                 ret = __btrfs_map_block(fs_info, REQ_GET_READ_MIRRORS,
4165                              logical, &tmp_length, &tmp_bbio, 0);
4166                 if (ret) {
4167                         WARN_ON(tmp_bbio != NULL);
4168                         goto out;
4169                 }
4170
4171                 tmp_num_stripes = tmp_bbio->num_stripes;
4172                 if (mirror_num > tmp_num_stripes) {
4173                         /*
4174                          * REQ_GET_READ_MIRRORS does not contain this
4175                          * mirror, that means that the requested area
4176                          * is not left of the left cursor
4177                          */
4178                         ret = -EIO;
4179                         kfree(tmp_bbio);
4180                         goto out;
4181                 }
4182
4183                 /*
4184                  * process the rest of the function using the mirror_num
4185                  * of the source drive. Therefore look it up first.
4186                  * At the end, patch the device pointer to the one of the
4187                  * target drive.
4188                  */
4189                 for (i = 0; i < tmp_num_stripes; i++) {
4190                         if (tmp_bbio->stripes[i].dev->devid == srcdev_devid) {
4191                                 /*
4192                                  * In case of DUP, in order to keep it
4193                                  * simple, only add the mirror with the
4194                                  * lowest physical address
4195                                  */
4196                                 if (found &&
4197                                     physical_of_found <=
4198                                      tmp_bbio->stripes[i].physical)
4199                                         continue;
4200                                 index_srcdev = i;
4201                                 found = 1;
4202                                 physical_of_found =
4203                                         tmp_bbio->stripes[i].physical;
4204                         }
4205                 }
4206
4207                 if (found) {
4208                         mirror_num = index_srcdev + 1;
4209                         patch_the_first_stripe_for_dev_replace = 1;
4210                         physical_to_patch_in_first_stripe = physical_of_found;
4211                 } else {
4212                         WARN_ON(1);
4213                         ret = -EIO;
4214                         kfree(tmp_bbio);
4215                         goto out;
4216                 }
4217
4218                 kfree(tmp_bbio);
4219         } else if (mirror_num > map->num_stripes) {
4220                 mirror_num = 0;
4221         }
4222
4223         num_stripes = 1;
4224         stripe_index = 0;
4225         stripe_nr_orig = stripe_nr;
4226         stripe_nr_end = (offset + *length + map->stripe_len - 1) &
4227                         (~(map->stripe_len - 1));
4228         do_div(stripe_nr_end, map->stripe_len);
4229         stripe_end_offset = stripe_nr_end * map->stripe_len -
4230                             (offset + *length);
4231         if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
4232                 if (rw & REQ_DISCARD)
4233                         num_stripes = min_t(u64, map->num_stripes,
4234                                             stripe_nr_end - stripe_nr_orig);
4235                 stripe_index = do_div(stripe_nr, map->num_stripes);
4236         } else if (map->type & BTRFS_BLOCK_GROUP_RAID1) {
4237                 if (rw & (REQ_WRITE | REQ_DISCARD | REQ_GET_READ_MIRRORS))
4238                         num_stripes = map->num_stripes;
4239                 else if (mirror_num)
4240                         stripe_index = mirror_num - 1;
4241                 else {
4242                         stripe_index = find_live_mirror(fs_info, map, 0,
4243                                             map->num_stripes,
4244                                             current->pid % map->num_stripes,
4245                                             dev_replace_is_ongoing);
4246                         mirror_num = stripe_index + 1;
4247                 }
4248
4249         } else if (map->type & BTRFS_BLOCK_GROUP_DUP) {
4250                 if (rw & (REQ_WRITE | REQ_DISCARD | REQ_GET_READ_MIRRORS)) {
4251                         num_stripes = map->num_stripes;
4252                 } else if (mirror_num) {
4253                         stripe_index = mirror_num - 1;
4254                 } else {
4255                         mirror_num = 1;
4256                 }
4257
4258         } else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
4259                 int factor = map->num_stripes / map->sub_stripes;
4260
4261                 stripe_index = do_div(stripe_nr, factor);
4262                 stripe_index *= map->sub_stripes;
4263
4264                 if (rw & (REQ_WRITE | REQ_GET_READ_MIRRORS))
4265                         num_stripes = map->sub_stripes;
4266                 else if (rw & REQ_DISCARD)
4267                         num_stripes = min_t(u64, map->sub_stripes *
4268                                             (stripe_nr_end - stripe_nr_orig),
4269                                             map->num_stripes);
4270                 else if (mirror_num)
4271                         stripe_index += mirror_num - 1;
4272                 else {
4273                         int old_stripe_index = stripe_index;
4274                         stripe_index = find_live_mirror(fs_info, map,
4275                                               stripe_index,
4276                                               map->sub_stripes, stripe_index +
4277                                               current->pid % map->sub_stripes,
4278                                               dev_replace_is_ongoing);
4279                         mirror_num = stripe_index - old_stripe_index + 1;
4280                 }
4281         } else {
4282                 /*
4283                  * after this do_div call, stripe_nr is the number of stripes
4284                  * on this device we have to walk to find the data, and
4285                  * stripe_index is the number of our device in the stripe array
4286                  */
4287                 stripe_index = do_div(stripe_nr, map->num_stripes);
4288                 mirror_num = stripe_index + 1;
4289         }
4290         BUG_ON(stripe_index >= map->num_stripes);
4291
4292         num_alloc_stripes = num_stripes;
4293         if (dev_replace_is_ongoing) {
4294                 if (rw & (REQ_WRITE | REQ_DISCARD))
4295                         num_alloc_stripes <<= 1;
4296                 if (rw & REQ_GET_READ_MIRRORS)
4297                         num_alloc_stripes++;
4298         }
4299         bbio = kzalloc(btrfs_bio_size(num_alloc_stripes), GFP_NOFS);
4300         if (!bbio) {
4301                 ret = -ENOMEM;
4302                 goto out;
4303         }
4304         atomic_set(&bbio->error, 0);
4305
4306         if (rw & REQ_DISCARD) {
4307                 int factor = 0;
4308                 int sub_stripes = 0;
4309                 u64 stripes_per_dev = 0;
4310                 u32 remaining_stripes = 0;
4311                 u32 last_stripe = 0;
4312
4313                 if (map->type &
4314                     (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID10)) {
4315                         if (map->type & BTRFS_BLOCK_GROUP_RAID0)
4316                                 sub_stripes = 1;
4317                         else
4318                                 sub_stripes = map->sub_stripes;
4319
4320                         factor = map->num_stripes / sub_stripes;
4321                         stripes_per_dev = div_u64_rem(stripe_nr_end -
4322                                                       stripe_nr_orig,
4323                                                       factor,
4324                                                       &remaining_stripes);
4325                         div_u64_rem(stripe_nr_end - 1, factor, &last_stripe);
4326                         last_stripe *= sub_stripes;
4327                 }
4328
4329                 for (i = 0; i < num_stripes; i++) {
4330                         bbio->stripes[i].physical =
4331                                 map->stripes[stripe_index].physical +
4332                                 stripe_offset + stripe_nr * map->stripe_len;
4333                         bbio->stripes[i].dev = map->stripes[stripe_index].dev;
4334
4335                         if (map->type & (BTRFS_BLOCK_GROUP_RAID0 |
4336                                          BTRFS_BLOCK_GROUP_RAID10)) {
4337                                 bbio->stripes[i].length = stripes_per_dev *
4338                                                           map->stripe_len;
4339
4340                                 if (i / sub_stripes < remaining_stripes)
4341                                         bbio->stripes[i].length +=
4342                                                 map->stripe_len;
4343
4344                                 /*
4345                                  * Special for the first stripe and
4346                                  * the last stripe:
4347                                  *
4348                                  * |-------|...|-------|
4349                                  *     |----------|
4350                                  *    off     end_off
4351                                  */
4352                                 if (i < sub_stripes)
4353                                         bbio->stripes[i].length -=
4354                                                 stripe_offset;
4355
4356                                 if (stripe_index >= last_stripe &&
4357                                     stripe_index <= (last_stripe +
4358                                                      sub_stripes - 1))
4359                                         bbio->stripes[i].length -=
4360                                                 stripe_end_offset;
4361
4362                                 if (i == sub_stripes - 1)
4363                                         stripe_offset = 0;
4364                         } else
4365                                 bbio->stripes[i].length = *length;
4366
4367                         stripe_index++;
4368                         if (stripe_index == map->num_stripes) {
4369                                 /* This could only happen for RAID0/10 */
4370                                 stripe_index = 0;
4371                                 stripe_nr++;
4372                         }
4373                 }
4374         } else {
4375                 for (i = 0; i < num_stripes; i++) {
4376                         bbio->stripes[i].physical =
4377                                 map->stripes[stripe_index].physical +
4378                                 stripe_offset +
4379                                 stripe_nr * map->stripe_len;
4380                         bbio->stripes[i].dev =
4381                                 map->stripes[stripe_index].dev;
4382                         stripe_index++;
4383                 }
4384         }
4385
4386         if (rw & (REQ_WRITE | REQ_GET_READ_MIRRORS)) {
4387                 if (map->type & (BTRFS_BLOCK_GROUP_RAID1 |
4388                                  BTRFS_BLOCK_GROUP_RAID10 |
4389                                  BTRFS_BLOCK_GROUP_DUP)) {
4390                         max_errors = 1;
4391                 }
4392         }
4393
4394         if (dev_replace_is_ongoing && (rw & (REQ_WRITE | REQ_DISCARD)) &&
4395             dev_replace->tgtdev != NULL) {
4396                 int index_where_to_add;
4397                 u64 srcdev_devid = dev_replace->srcdev->devid;
4398
4399                 /*
4400                  * duplicate the write operations while the dev replace
4401                  * procedure is running. Since the copying of the old disk
4402                  * to the new disk takes place at run time while the
4403                  * filesystem is mounted writable, the regular write
4404                  * operations to the old disk have to be duplicated to go
4405                  * to the new disk as well.
4406                  * Note that device->missing is handled by the caller, and
4407                  * that the write to the old disk is already set up in the
4408                  * stripes array.
4409                  */
4410                 index_where_to_add = num_stripes;
4411                 for (i = 0; i < num_stripes; i++) {
4412                         if (bbio->stripes[i].dev->devid == srcdev_devid) {
4413                                 /* write to new disk, too */
4414                                 struct btrfs_bio_stripe *new =
4415                                         bbio->stripes + index_where_to_add;
4416                                 struct btrfs_bio_stripe *old =
4417                                         bbio->stripes + i;
4418
4419                                 new->physical = old->physical;
4420                                 new->length = old->length;
4421                                 new->dev = dev_replace->tgtdev;
4422                                 index_where_to_add++;
4423                                 max_errors++;
4424                         }
4425                 }
4426                 num_stripes = index_where_to_add;
4427         } else if (dev_replace_is_ongoing && (rw & REQ_GET_READ_MIRRORS) &&
4428                    dev_replace->tgtdev != NULL) {
4429                 u64 srcdev_devid = dev_replace->srcdev->devid;
4430                 int index_srcdev = 0;
4431                 int found = 0;
4432                 u64 physical_of_found = 0;
4433
4434                 /*
4435                  * During the dev-replace procedure, the target drive can
4436                  * also be used to read data in case it is needed to repair
4437                  * a corrupt block elsewhere. This is possible if the
4438                  * requested area is left of the left cursor. In this area,
4439                  * the target drive is a full copy of the source drive.
4440                  */
4441                 for (i = 0; i < num_stripes; i++) {
4442                         if (bbio->stripes[i].dev->devid == srcdev_devid) {
4443                                 /*
4444                                  * In case of DUP, in order to keep it
4445                                  * simple, only add the mirror with the
4446                                  * lowest physical address
4447                                  */
4448                                 if (found &&
4449                                     physical_of_found <=
4450                                      bbio->stripes[i].physical)
4451                                         continue;
4452                                 index_srcdev = i;
4453                                 found = 1;
4454                                 physical_of_found = bbio->stripes[i].physical;
4455                         }
4456                 }
4457                 if (found) {
4458                         u64 length = map->stripe_len;
4459
4460                         if (physical_of_found + length <=
4461                             dev_replace->cursor_left) {
4462                                 struct btrfs_bio_stripe *tgtdev_stripe =
4463                                         bbio->stripes + num_stripes;
4464
4465                                 tgtdev_stripe->physical = physical_of_found;
4466                                 tgtdev_stripe->length =
4467                                         bbio->stripes[index_srcdev].length;
4468                                 tgtdev_stripe->dev = dev_replace->tgtdev;
4469
4470                                 num_stripes++;
4471                         }
4472                 }
4473         }
4474
4475         *bbio_ret = bbio;
4476         bbio->num_stripes = num_stripes;
4477         bbio->max_errors = max_errors;
4478         bbio->mirror_num = mirror_num;
4479
4480         /*
4481          * this is the case that REQ_READ && dev_replace_is_ongoing &&
4482          * mirror_num == num_stripes + 1 && dev_replace target drive is
4483          * available as a mirror
4484          */
4485         if (patch_the_first_stripe_for_dev_replace && num_stripes > 0) {
4486                 WARN_ON(num_stripes > 1);
4487                 bbio->stripes[0].dev = dev_replace->tgtdev;
4488                 bbio->stripes[0].physical = physical_to_patch_in_first_stripe;
4489                 bbio->mirror_num = map->num_stripes + 1;
4490         }
4491 out:
4492         if (dev_replace_is_ongoing)
4493                 btrfs_dev_replace_unlock(dev_replace);
4494         free_extent_map(em);
4495         return ret;
4496 }
4497
4498 int btrfs_map_block(struct btrfs_fs_info *fs_info, int rw,
4499                       u64 logical, u64 *length,
4500                       struct btrfs_bio **bbio_ret, int mirror_num)
4501 {
4502         return __btrfs_map_block(fs_info, rw, logical, length, bbio_ret,
4503                                  mirror_num);
4504 }
4505
4506 int btrfs_rmap_block(struct btrfs_mapping_tree *map_tree,
4507                      u64 chunk_start, u64 physical, u64 devid,
4508                      u64 **logical, int *naddrs, int *stripe_len)
4509 {
4510         struct extent_map_tree *em_tree = &map_tree->map_tree;
4511         struct extent_map *em;
4512         struct map_lookup *map;
4513         u64 *buf;
4514         u64 bytenr;
4515         u64 length;
4516         u64 stripe_nr;
4517         int i, j, nr = 0;
4518
4519         read_lock(&em_tree->lock);
4520         em = lookup_extent_mapping(em_tree, chunk_start, 1);
4521         read_unlock(&em_tree->lock);
4522
4523         BUG_ON(!em || em->start != chunk_start);
4524         map = (struct map_lookup *)em->bdev;
4525
4526         length = em->len;
4527         if (map->type & BTRFS_BLOCK_GROUP_RAID10)
4528                 do_div(length, map->num_stripes / map->sub_stripes);
4529         else if (map->type & BTRFS_BLOCK_GROUP_RAID0)
4530                 do_div(length, map->num_stripes);
4531
4532         buf = kzalloc(sizeof(u64) * map->num_stripes, GFP_NOFS);
4533         BUG_ON(!buf); /* -ENOMEM */
4534
4535         for (i = 0; i < map->num_stripes; i++) {
4536                 if (devid && map->stripes[i].dev->devid != devid)
4537                         continue;
4538                 if (map->stripes[i].physical > physical ||
4539                     map->stripes[i].physical + length <= physical)
4540                         continue;
4541
4542                 stripe_nr = physical - map->stripes[i].physical;
4543                 do_div(stripe_nr, map->stripe_len);
4544
4545                 if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
4546                         stripe_nr = stripe_nr * map->num_stripes + i;
4547                         do_div(stripe_nr, map->sub_stripes);
4548                 } else if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
4549                         stripe_nr = stripe_nr * map->num_stripes + i;
4550                 }
4551                 bytenr = chunk_start + stripe_nr * map->stripe_len;
4552                 WARN_ON(nr >= map->num_stripes);
4553                 for (j = 0; j < nr; j++) {
4554                         if (buf[j] == bytenr)
4555                                 break;
4556                 }
4557                 if (j == nr) {
4558                         WARN_ON(nr >= map->num_stripes);
4559                         buf[nr++] = bytenr;
4560                 }
4561         }
4562
4563         *logical = buf;
4564         *naddrs = nr;
4565         *stripe_len = map->stripe_len;
4566
4567         free_extent_map(em);
4568         return 0;
4569 }
4570
4571 static void *merge_stripe_index_into_bio_private(void *bi_private,
4572                                                  unsigned int stripe_index)
4573 {
4574         /*
4575          * with single, dup, RAID0, RAID1 and RAID10, stripe_index is
4576          * at most 1.
4577          * The alternative solution (instead of stealing bits from the
4578          * pointer) would be to allocate an intermediate structure
4579          * that contains the old private pointer plus the stripe_index.
4580          */
4581         BUG_ON((((uintptr_t)bi_private) & 3) != 0);
4582         BUG_ON(stripe_index > 3);
4583         return (void *)(((uintptr_t)bi_private) | stripe_index);
4584 }
4585
4586 static struct btrfs_bio *extract_bbio_from_bio_private(void *bi_private)
4587 {
4588         return (struct btrfs_bio *)(((uintptr_t)bi_private) & ~((uintptr_t)3));
4589 }
4590
4591 static unsigned int extract_stripe_index_from_bio_private(void *bi_private)
4592 {
4593         return (unsigned int)((uintptr_t)bi_private) & 3;
4594 }
4595
4596 static void btrfs_end_bio(struct bio *bio, int err)
4597 {
4598         struct btrfs_bio *bbio = extract_bbio_from_bio_private(bio->bi_private);
4599         int is_orig_bio = 0;
4600
4601         if (err) {
4602                 atomic_inc(&bbio->error);
4603                 if (err == -EIO || err == -EREMOTEIO) {
4604                         unsigned int stripe_index =
4605                                 extract_stripe_index_from_bio_private(
4606                                         bio->bi_private);
4607                         struct btrfs_device *dev;
4608
4609                         BUG_ON(stripe_index >= bbio->num_stripes);
4610                         dev = bbio->stripes[stripe_index].dev;
4611                         if (dev->bdev) {
4612                                 if (bio->bi_rw & WRITE)
4613                                         btrfs_dev_stat_inc(dev,
4614                                                 BTRFS_DEV_STAT_WRITE_ERRS);
4615                                 else
4616                                         btrfs_dev_stat_inc(dev,
4617                                                 BTRFS_DEV_STAT_READ_ERRS);
4618                                 if ((bio->bi_rw & WRITE_FLUSH) == WRITE_FLUSH)
4619                                         btrfs_dev_stat_inc(dev,
4620                                                 BTRFS_DEV_STAT_FLUSH_ERRS);
4621                                 btrfs_dev_stat_print_on_error(dev);
4622                         }
4623                 }
4624         }
4625
4626         if (bio == bbio->orig_bio)
4627                 is_orig_bio = 1;
4628
4629         if (atomic_dec_and_test(&bbio->stripes_pending)) {
4630                 if (!is_orig_bio) {
4631                         bio_put(bio);
4632                         bio = bbio->orig_bio;
4633                 }
4634                 bio->bi_private = bbio->private;
4635                 bio->bi_end_io = bbio->end_io;
4636                 bio->bi_bdev = (struct block_device *)
4637                                         (unsigned long)bbio->mirror_num;
4638                 /* only send an error to the higher layers if it is
4639                  * beyond the tolerance of the multi-bio
4640                  */
4641                 if (atomic_read(&bbio->error) > bbio->max_errors) {
4642                         err = -EIO;
4643                 } else {
4644                         /*
4645                          * this bio is actually up to date, we didn't
4646                          * go over the max number of errors
4647                          */
4648                         set_bit(BIO_UPTODATE, &bio->bi_flags);
4649                         err = 0;
4650                 }
4651                 kfree(bbio);
4652
4653                 bio_endio(bio, err);
4654         } else if (!is_orig_bio) {
4655                 bio_put(bio);
4656         }
4657 }
4658
4659 struct async_sched {
4660         struct bio *bio;
4661         int rw;
4662         struct btrfs_fs_info *info;
4663         struct btrfs_work work;
4664 };
4665
4666 /*
4667  * see run_scheduled_bios for a description of why bios are collected for
4668  * async submit.
4669  *
4670  * This will add one bio to the pending list for a device and make sure
4671  * the work struct is scheduled.
4672  */
4673 static noinline void schedule_bio(struct btrfs_root *root,
4674                                  struct btrfs_device *device,
4675                                  int rw, struct bio *bio)
4676 {
4677         int should_queue = 1;
4678         struct btrfs_pending_bios *pending_bios;
4679
4680         /* don't bother with additional async steps for reads, right now */
4681         if (!(rw & REQ_WRITE)) {
4682                 bio_get(bio);
4683                 btrfsic_submit_bio(rw, bio);
4684                 bio_put(bio);
4685                 return;
4686         }
4687
4688         /*
4689          * nr_async_bios allows us to reliably return congestion to the
4690          * higher layers.  Otherwise, the async bio makes it appear we have
4691          * made progress against dirty pages when we've really just put it
4692          * on a queue for later
4693          */
4694         atomic_inc(&root->fs_info->nr_async_bios);
4695         WARN_ON(bio->bi_next);
4696         bio->bi_next = NULL;
4697         bio->bi_rw |= rw;
4698
4699         spin_lock(&device->io_lock);
4700         if (bio->bi_rw & REQ_SYNC)
4701                 pending_bios = &device->pending_sync_bios;
4702         else
4703                 pending_bios = &device->pending_bios;
4704
4705         if (pending_bios->tail)
4706                 pending_bios->tail->bi_next = bio;
4707
4708         pending_bios->tail = bio;
4709         if (!pending_bios->head)
4710                 pending_bios->head = bio;
4711         if (device->running_pending)
4712                 should_queue = 0;
4713
4714         spin_unlock(&device->io_lock);
4715
4716         if (should_queue)
4717                 btrfs_queue_worker(&root->fs_info->submit_workers,
4718                                    &device->work);
4719 }
4720
4721 static int bio_size_ok(struct block_device *bdev, struct bio *bio,
4722                        sector_t sector)
4723 {
4724         struct bio_vec *prev;
4725         struct request_queue *q = bdev_get_queue(bdev);
4726         unsigned short max_sectors = queue_max_sectors(q);
4727         struct bvec_merge_data bvm = {
4728                 .bi_bdev = bdev,
4729                 .bi_sector = sector,
4730                 .bi_rw = bio->bi_rw,
4731         };
4732
4733         if (bio->bi_vcnt == 0) {
4734                 WARN_ON(1);
4735                 return 1;
4736         }
4737
4738         prev = &bio->bi_io_vec[bio->bi_vcnt - 1];
4739         if ((bio->bi_size >> 9) > max_sectors)
4740                 return 0;
4741
4742         if (!q->merge_bvec_fn)
4743                 return 1;
4744
4745         bvm.bi_size = bio->bi_size - prev->bv_len;
4746         if (q->merge_bvec_fn(q, &bvm, prev) < prev->bv_len)
4747                 return 0;
4748         return 1;
4749 }
4750
4751 static void submit_stripe_bio(struct btrfs_root *root, struct btrfs_bio *bbio,
4752                               struct bio *bio, u64 physical, int dev_nr,
4753                               int rw, int async)
4754 {
4755         struct btrfs_device *dev = bbio->stripes[dev_nr].dev;
4756
4757         bio->bi_private = bbio;
4758         bio->bi_private = merge_stripe_index_into_bio_private(
4759                         bio->bi_private, (unsigned int)dev_nr);
4760         bio->bi_end_io = btrfs_end_bio;
4761         bio->bi_sector = physical >> 9;
4762 #ifdef DEBUG
4763         {
4764                 struct rcu_string *name;
4765
4766                 rcu_read_lock();
4767                 name = rcu_dereference(dev->name);
4768                 pr_debug("btrfs_map_bio: rw %d, sector=%llu, dev=%lu "
4769                          "(%s id %llu), size=%u\n", rw,
4770                          (u64)bio->bi_sector, (u_long)dev->bdev->bd_dev,
4771                          name->str, dev->devid, bio->bi_size);
4772                 rcu_read_unlock();
4773         }
4774 #endif
4775         bio->bi_bdev = dev->bdev;
4776         if (async)
4777                 schedule_bio(root, dev, rw, bio);
4778         else
4779                 btrfsic_submit_bio(rw, bio);
4780 }
4781
4782 static int breakup_stripe_bio(struct btrfs_root *root, struct btrfs_bio *bbio,
4783                               struct bio *first_bio, struct btrfs_device *dev,
4784                               int dev_nr, int rw, int async)
4785 {
4786         struct bio_vec *bvec = first_bio->bi_io_vec;
4787         struct bio *bio;
4788         int nr_vecs = bio_get_nr_vecs(dev->bdev);
4789         u64 physical = bbio->stripes[dev_nr].physical;
4790
4791 again:
4792         bio = btrfs_bio_alloc(dev->bdev, physical >> 9, nr_vecs, GFP_NOFS);
4793         if (!bio)
4794                 return -ENOMEM;
4795
4796         while (bvec <= (first_bio->bi_io_vec + first_bio->bi_vcnt - 1)) {
4797                 if (bio_add_page(bio, bvec->bv_page, bvec->bv_len,
4798                                  bvec->bv_offset) < bvec->bv_len) {
4799                         u64 len = bio->bi_size;
4800
4801                         atomic_inc(&bbio->stripes_pending);
4802                         submit_stripe_bio(root, bbio, bio, physical, dev_nr,
4803                                           rw, async);
4804                         physical += len;
4805                         goto again;
4806                 }
4807                 bvec++;
4808         }
4809
4810         submit_stripe_bio(root, bbio, bio, physical, dev_nr, rw, async);
4811         return 0;
4812 }
4813
4814 static void bbio_error(struct btrfs_bio *bbio, struct bio *bio, u64 logical)
4815 {
4816         atomic_inc(&bbio->error);
4817         if (atomic_dec_and_test(&bbio->stripes_pending)) {
4818                 bio->bi_private = bbio->private;
4819                 bio->bi_end_io = bbio->end_io;
4820                 bio->bi_bdev = (struct block_device *)
4821                         (unsigned long)bbio->mirror_num;
4822                 bio->bi_sector = logical >> 9;
4823                 kfree(bbio);
4824                 bio_endio(bio, -EIO);
4825         }
4826 }
4827
4828 int btrfs_map_bio(struct btrfs_root *root, int rw, struct bio *bio,
4829                   int mirror_num, int async_submit)
4830 {
4831         struct btrfs_device *dev;
4832         struct bio *first_bio = bio;
4833         u64 logical = (u64)bio->bi_sector << 9;
4834         u64 length = 0;
4835         u64 map_length;
4836         int ret;
4837         int dev_nr = 0;
4838         int total_devs = 1;
4839         struct btrfs_bio *bbio = NULL;
4840
4841         length = bio->bi_size;
4842         map_length = length;
4843
4844         ret = btrfs_map_block(root->fs_info, rw, logical, &map_length, &bbio,
4845                               mirror_num);
4846         if (ret)
4847                 return ret;
4848
4849         total_devs = bbio->num_stripes;
4850         if (map_length < length) {
4851                 printk(KERN_CRIT "btrfs: mapping failed logical %llu bio len %llu "
4852                        "len %llu\n", (unsigned long long)logical,
4853                        (unsigned long long)length,
4854                        (unsigned long long)map_length);
4855                 BUG();
4856         }
4857
4858         bbio->orig_bio = first_bio;
4859         bbio->private = first_bio->bi_private;
4860         bbio->end_io = first_bio->bi_end_io;
4861         atomic_set(&bbio->stripes_pending, bbio->num_stripes);
4862
4863         while (dev_nr < total_devs) {
4864                 dev = bbio->stripes[dev_nr].dev;
4865                 if (!dev || !dev->bdev || (rw & WRITE && !dev->writeable)) {
4866                         bbio_error(bbio, first_bio, logical);
4867                         dev_nr++;
4868                         continue;
4869                 }
4870
4871                 /*
4872                  * Check and see if we're ok with this bio based on it's size
4873                  * and offset with the given device.
4874                  */
4875                 if (!bio_size_ok(dev->bdev, first_bio,
4876                                  bbio->stripes[dev_nr].physical >> 9)) {
4877                         ret = breakup_stripe_bio(root, bbio, first_bio, dev,
4878                                                  dev_nr, rw, async_submit);
4879                         BUG_ON(ret);
4880                         dev_nr++;
4881                         continue;
4882                 }
4883
4884                 if (dev_nr < total_devs - 1) {
4885                         bio = bio_clone(first_bio, GFP_NOFS);
4886                         BUG_ON(!bio); /* -ENOMEM */
4887                 } else {
4888                         bio = first_bio;
4889                 }
4890
4891                 submit_stripe_bio(root, bbio, bio,
4892                                   bbio->stripes[dev_nr].physical, dev_nr, rw,
4893                                   async_submit);
4894                 dev_nr++;
4895         }
4896         return 0;
4897 }
4898
4899 struct btrfs_device *btrfs_find_device(struct btrfs_fs_info *fs_info, u64 devid,
4900                                        u8 *uuid, u8 *fsid)
4901 {
4902         struct btrfs_device *device;
4903         struct btrfs_fs_devices *cur_devices;
4904
4905         cur_devices = fs_info->fs_devices;
4906         while (cur_devices) {
4907                 if (!fsid ||
4908                     !memcmp(cur_devices->fsid, fsid, BTRFS_UUID_SIZE)) {
4909                         device = __find_device(&cur_devices->devices,
4910                                                devid, uuid);
4911                         if (device)
4912                                 return device;
4913                 }
4914                 cur_devices = cur_devices->seed;
4915         }
4916         return NULL;
4917 }
4918
4919 static struct btrfs_device *add_missing_dev(struct btrfs_root *root,
4920                                             u64 devid, u8 *dev_uuid)
4921 {
4922         struct btrfs_device *device;
4923         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
4924
4925         device = kzalloc(sizeof(*device), GFP_NOFS);
4926         if (!device)
4927                 return NULL;
4928         list_add(&device->dev_list,
4929                  &fs_devices->devices);
4930         device->dev_root = root->fs_info->dev_root;
4931         device->devid = devid;
4932         device->work.func = pending_bios_fn;
4933         device->fs_devices = fs_devices;
4934         device->missing = 1;
4935         fs_devices->num_devices++;
4936         fs_devices->missing_devices++;
4937         spin_lock_init(&device->io_lock);
4938         INIT_LIST_HEAD(&device->dev_alloc_list);
4939         memcpy(device->uuid, dev_uuid, BTRFS_UUID_SIZE);
4940         return device;
4941 }
4942
4943 static int read_one_chunk(struct btrfs_root *root, struct btrfs_key *key,
4944                           struct extent_buffer *leaf,
4945                           struct btrfs_chunk *chunk)
4946 {
4947         struct btrfs_mapping_tree *map_tree = &root->fs_info->mapping_tree;
4948         struct map_lookup *map;
4949         struct extent_map *em;
4950         u64 logical;
4951         u64 length;
4952         u64 devid;
4953         u8 uuid[BTRFS_UUID_SIZE];
4954         int num_stripes;
4955         int ret;
4956         int i;
4957
4958         logical = key->offset;
4959         length = btrfs_chunk_length(leaf, chunk);
4960
4961         read_lock(&map_tree->map_tree.lock);
4962         em = lookup_extent_mapping(&map_tree->map_tree, logical, 1);
4963         read_unlock(&map_tree->map_tree.lock);
4964
4965         /* already mapped? */
4966         if (em && em->start <= logical && em->start + em->len > logical) {
4967                 free_extent_map(em);
4968                 return 0;
4969         } else if (em) {
4970                 free_extent_map(em);
4971         }
4972
4973         em = alloc_extent_map();
4974         if (!em)
4975                 return -ENOMEM;
4976         num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
4977         map = kmalloc(map_lookup_size(num_stripes), GFP_NOFS);
4978         if (!map) {
4979                 free_extent_map(em);
4980                 return -ENOMEM;
4981         }
4982
4983         em->bdev = (struct block_device *)map;
4984         em->start = logical;
4985         em->len = length;
4986         em->orig_start = 0;
4987         em->block_start = 0;
4988         em->block_len = em->len;
4989
4990         map->num_stripes = num_stripes;
4991         map->io_width = btrfs_chunk_io_width(leaf, chunk);
4992         map->io_align = btrfs_chunk_io_align(leaf, chunk);
4993         map->sector_size = btrfs_chunk_sector_size(leaf, chunk);
4994         map->stripe_len = btrfs_chunk_stripe_len(leaf, chunk);
4995         map->type = btrfs_chunk_type(leaf, chunk);
4996         map->sub_stripes = btrfs_chunk_sub_stripes(leaf, chunk);
4997         for (i = 0; i < num_stripes; i++) {
4998                 map->stripes[i].physical =
4999                         btrfs_stripe_offset_nr(leaf, chunk, i);
5000                 devid = btrfs_stripe_devid_nr(leaf, chunk, i);
5001                 read_extent_buffer(leaf, uuid, (unsigned long)
5002                                    btrfs_stripe_dev_uuid_nr(chunk, i),
5003                                    BTRFS_UUID_SIZE);
5004                 map->stripes[i].dev = btrfs_find_device(root->fs_info, devid,
5005                                                         uuid, NULL);
5006                 if (!map->stripes[i].dev && !btrfs_test_opt(root, DEGRADED)) {
5007                         kfree(map);
5008                         free_extent_map(em);
5009                         return -EIO;
5010                 }
5011                 if (!map->stripes[i].dev) {
5012                         map->stripes[i].dev =
5013                                 add_missing_dev(root, devid, uuid);
5014                         if (!map->stripes[i].dev) {
5015                                 kfree(map);
5016                                 free_extent_map(em);
5017                                 return -EIO;
5018                         }
5019                 }
5020                 map->stripes[i].dev->in_fs_metadata = 1;
5021         }
5022
5023         write_lock(&map_tree->map_tree.lock);
5024         ret = add_extent_mapping(&map_tree->map_tree, em);
5025         write_unlock(&map_tree->map_tree.lock);
5026         BUG_ON(ret); /* Tree corruption */
5027         free_extent_map(em);
5028
5029         return 0;
5030 }
5031
5032 static void fill_device_from_item(struct extent_buffer *leaf,
5033                                  struct btrfs_dev_item *dev_item,
5034                                  struct btrfs_device *device)
5035 {
5036         unsigned long ptr;
5037
5038         device->devid = btrfs_device_id(leaf, dev_item);
5039         device->disk_total_bytes = btrfs_device_total_bytes(leaf, dev_item);
5040         device->total_bytes = device->disk_total_bytes;
5041         device->bytes_used = btrfs_device_bytes_used(leaf, dev_item);
5042         device->type = btrfs_device_type(leaf, dev_item);
5043         device->io_align = btrfs_device_io_align(leaf, dev_item);
5044         device->io_width = btrfs_device_io_width(leaf, dev_item);
5045         device->sector_size = btrfs_device_sector_size(leaf, dev_item);
5046         WARN_ON(device->devid == BTRFS_DEV_REPLACE_DEVID);
5047         device->is_tgtdev_for_dev_replace = 0;
5048
5049         ptr = (unsigned long)btrfs_device_uuid(dev_item);
5050         read_extent_buffer(leaf, device->uuid, ptr, BTRFS_UUID_SIZE);
5051 }
5052
5053 static int open_seed_devices(struct btrfs_root *root, u8 *fsid)
5054 {
5055         struct btrfs_fs_devices *fs_devices;
5056         int ret;
5057
5058         BUG_ON(!mutex_is_locked(&uuid_mutex));
5059
5060         fs_devices = root->fs_info->fs_devices->seed;
5061         while (fs_devices) {
5062                 if (!memcmp(fs_devices->fsid, fsid, BTRFS_UUID_SIZE)) {
5063                         ret = 0;
5064                         goto out;
5065                 }
5066                 fs_devices = fs_devices->seed;
5067         }
5068
5069         fs_devices = find_fsid(fsid);
5070         if (!fs_devices) {
5071                 ret = -ENOENT;
5072                 goto out;
5073         }
5074
5075         fs_devices = clone_fs_devices(fs_devices);
5076         if (IS_ERR(fs_devices)) {
5077                 ret = PTR_ERR(fs_devices);
5078                 goto out;
5079         }
5080
5081         ret = __btrfs_open_devices(fs_devices, FMODE_READ,
5082                                    root->fs_info->bdev_holder);
5083         if (ret) {
5084                 free_fs_devices(fs_devices);
5085                 goto out;
5086         }
5087
5088         if (!fs_devices->seeding) {
5089                 __btrfs_close_devices(fs_devices);
5090                 free_fs_devices(fs_devices);
5091                 ret = -EINVAL;
5092                 goto out;
5093         }
5094
5095         fs_devices->seed = root->fs_info->fs_devices->seed;
5096         root->fs_info->fs_devices->seed = fs_devices;
5097 out:
5098         return ret;
5099 }
5100
5101 static int read_one_dev(struct btrfs_root *root,
5102                         struct extent_buffer *leaf,
5103                         struct btrfs_dev_item *dev_item)
5104 {
5105         struct btrfs_device *device;
5106         u64 devid;
5107         int ret;
5108         u8 fs_uuid[BTRFS_UUID_SIZE];
5109         u8 dev_uuid[BTRFS_UUID_SIZE];
5110
5111         devid = btrfs_device_id(leaf, dev_item);
5112         read_extent_buffer(leaf, dev_uuid,
5113                            (unsigned long)btrfs_device_uuid(dev_item),
5114                            BTRFS_UUID_SIZE);
5115         read_extent_buffer(leaf, fs_uuid,
5116                            (unsigned long)btrfs_device_fsid(dev_item),
5117                            BTRFS_UUID_SIZE);
5118
5119         if (memcmp(fs_uuid, root->fs_info->fsid, BTRFS_UUID_SIZE)) {
5120                 ret = open_seed_devices(root, fs_uuid);
5121                 if (ret && !btrfs_test_opt(root, DEGRADED))
5122                         return ret;
5123         }
5124
5125         device = btrfs_find_device(root->fs_info, devid, dev_uuid, fs_uuid);
5126         if (!device || !device->bdev) {
5127                 if (!btrfs_test_opt(root, DEGRADED))
5128                         return -EIO;
5129
5130                 if (!device) {
5131                         printk(KERN_WARNING "warning devid %llu missing\n",
5132                                (unsigned long long)devid);
5133                         device = add_missing_dev(root, devid, dev_uuid);
5134                         if (!device)
5135                                 return -ENOMEM;
5136                 } else if (!device->missing) {
5137                         /*
5138                          * this happens when a device that was properly setup
5139                          * in the device info lists suddenly goes bad.
5140                          * device->bdev is NULL, and so we have to set
5141                          * device->missing to one here
5142                          */
5143                         root->fs_info->fs_devices->missing_devices++;
5144                         device->missing = 1;
5145                 }
5146         }
5147
5148         if (device->fs_devices != root->fs_info->fs_devices) {
5149                 BUG_ON(device->writeable);
5150                 if (device->generation !=
5151                     btrfs_device_generation(leaf, dev_item))
5152                         return -EINVAL;
5153         }
5154
5155         fill_device_from_item(leaf, dev_item, device);
5156         device->dev_root = root->fs_info->dev_root;
5157         device->in_fs_metadata = 1;
5158         if (device->writeable && !device->is_tgtdev_for_dev_replace) {
5159                 device->fs_devices->total_rw_bytes += device->total_bytes;
5160                 spin_lock(&root->fs_info->free_chunk_lock);
5161                 root->fs_info->free_chunk_space += device->total_bytes -
5162                         device->bytes_used;
5163                 spin_unlock(&root->fs_info->free_chunk_lock);
5164         }
5165         ret = 0;
5166         return ret;
5167 }
5168
5169 int btrfs_read_sys_array(struct btrfs_root *root)
5170 {
5171         struct btrfs_super_block *super_copy = root->fs_info->super_copy;
5172         struct extent_buffer *sb;
5173         struct btrfs_disk_key *disk_key;
5174         struct btrfs_chunk *chunk;
5175         u8 *ptr;
5176         unsigned long sb_ptr;
5177         int ret = 0;
5178         u32 num_stripes;
5179         u32 array_size;
5180         u32 len = 0;
5181         u32 cur;
5182         struct btrfs_key key;
5183
5184         sb = btrfs_find_create_tree_block(root, BTRFS_SUPER_INFO_OFFSET,
5185                                           BTRFS_SUPER_INFO_SIZE);
5186         if (!sb)
5187                 return -ENOMEM;
5188         btrfs_set_buffer_uptodate(sb);
5189         btrfs_set_buffer_lockdep_class(root->root_key.objectid, sb, 0);
5190         /*
5191          * The sb extent buffer is artifical and just used to read the system array.
5192          * btrfs_set_buffer_uptodate() call does not properly mark all it's
5193          * pages up-to-date when the page is larger: extent does not cover the
5194          * whole page and consequently check_page_uptodate does not find all
5195          * the page's extents up-to-date (the hole beyond sb),
5196          * write_extent_buffer then triggers a WARN_ON.
5197          *
5198          * Regular short extents go through mark_extent_buffer_dirty/writeback cycle,
5199          * but sb spans only this function. Add an explicit SetPageUptodate call
5200          * to silence the warning eg. on PowerPC 64.
5201          */
5202         if (PAGE_CACHE_SIZE > BTRFS_SUPER_INFO_SIZE)
5203                 SetPageUptodate(sb->pages[0]);
5204
5205         write_extent_buffer(sb, super_copy, 0, BTRFS_SUPER_INFO_SIZE);
5206         array_size = btrfs_super_sys_array_size(super_copy);
5207
5208         ptr = super_copy->sys_chunk_array;
5209         sb_ptr = offsetof(struct btrfs_super_block, sys_chunk_array);
5210         cur = 0;
5211
5212         while (cur < array_size) {
5213                 disk_key = (struct btrfs_disk_key *)ptr;
5214                 btrfs_disk_key_to_cpu(&key, disk_key);
5215
5216                 len = sizeof(*disk_key); ptr += len;
5217                 sb_ptr += len;
5218                 cur += len;
5219
5220                 if (key.type == BTRFS_CHUNK_ITEM_KEY) {
5221                         chunk = (struct btrfs_chunk *)sb_ptr;
5222                         ret = read_one_chunk(root, &key, sb, chunk);
5223                         if (ret)
5224                                 break;
5225                         num_stripes = btrfs_chunk_num_stripes(sb, chunk);
5226                         len = btrfs_chunk_item_size(num_stripes);
5227                 } else {
5228                         ret = -EIO;
5229                         break;
5230                 }
5231                 ptr += len;
5232                 sb_ptr += len;
5233                 cur += len;
5234         }
5235         free_extent_buffer(sb);
5236         return ret;
5237 }
5238
5239 int btrfs_read_chunk_tree(struct btrfs_root *root)
5240 {
5241         struct btrfs_path *path;
5242         struct extent_buffer *leaf;
5243         struct btrfs_key key;
5244         struct btrfs_key found_key;
5245         int ret;
5246         int slot;
5247
5248         root = root->fs_info->chunk_root;
5249
5250         path = btrfs_alloc_path();
5251         if (!path)
5252                 return -ENOMEM;
5253
5254         mutex_lock(&uuid_mutex);
5255         lock_chunks(root);
5256
5257         /* first we search for all of the device items, and then we
5258          * read in all of the chunk items.  This way we can create chunk
5259          * mappings that reference all of the devices that are afound
5260          */
5261         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
5262         key.offset = 0;
5263         key.type = 0;
5264 again:
5265         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
5266         if (ret < 0)
5267                 goto error;
5268         while (1) {
5269                 leaf = path->nodes[0];
5270                 slot = path->slots[0];
5271                 if (slot >= btrfs_header_nritems(leaf)) {
5272                         ret = btrfs_next_leaf(root, path);
5273                         if (ret == 0)
5274                                 continue;
5275                         if (ret < 0)
5276                                 goto error;
5277                         break;
5278                 }
5279                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
5280                 if (key.objectid == BTRFS_DEV_ITEMS_OBJECTID) {
5281                         if (found_key.objectid != BTRFS_DEV_ITEMS_OBJECTID)
5282                                 break;
5283                         if (found_key.type == BTRFS_DEV_ITEM_KEY) {
5284                                 struct btrfs_dev_item *dev_item;
5285                                 dev_item = btrfs_item_ptr(leaf, slot,
5286                                                   struct btrfs_dev_item);
5287                                 ret = read_one_dev(root, leaf, dev_item);
5288                                 if (ret)
5289                                         goto error;
5290                         }
5291                 } else if (found_key.type == BTRFS_CHUNK_ITEM_KEY) {
5292                         struct btrfs_chunk *chunk;
5293                         chunk = btrfs_item_ptr(leaf, slot, struct btrfs_chunk);
5294                         ret = read_one_chunk(root, &found_key, leaf, chunk);
5295                         if (ret)
5296                                 goto error;
5297                 }
5298                 path->slots[0]++;
5299         }
5300         if (key.objectid == BTRFS_DEV_ITEMS_OBJECTID) {
5301                 key.objectid = 0;
5302                 btrfs_release_path(path);
5303                 goto again;
5304         }
5305         ret = 0;
5306 error:
5307         unlock_chunks(root);
5308         mutex_unlock(&uuid_mutex);
5309
5310         btrfs_free_path(path);
5311         return ret;
5312 }
5313
5314 static void __btrfs_reset_dev_stats(struct btrfs_device *dev)
5315 {
5316         int i;
5317
5318         for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++)
5319                 btrfs_dev_stat_reset(dev, i);
5320 }
5321
5322 int btrfs_init_dev_stats(struct btrfs_fs_info *fs_info)
5323 {
5324         struct btrfs_key key;
5325         struct btrfs_key found_key;
5326         struct btrfs_root *dev_root = fs_info->dev_root;
5327         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
5328         struct extent_buffer *eb;
5329         int slot;
5330         int ret = 0;
5331         struct btrfs_device *device;
5332         struct btrfs_path *path = NULL;
5333         int i;
5334
5335         path = btrfs_alloc_path();
5336         if (!path) {
5337                 ret = -ENOMEM;
5338                 goto out;
5339         }
5340
5341         mutex_lock(&fs_devices->device_list_mutex);
5342         list_for_each_entry(device, &fs_devices->devices, dev_list) {
5343                 int item_size;
5344                 struct btrfs_dev_stats_item *ptr;
5345
5346                 key.objectid = 0;
5347                 key.type = BTRFS_DEV_STATS_KEY;
5348                 key.offset = device->devid;
5349                 ret = btrfs_search_slot(NULL, dev_root, &key, path, 0, 0);
5350                 if (ret) {
5351                         __btrfs_reset_dev_stats(device);
5352                         device->dev_stats_valid = 1;
5353                         btrfs_release_path(path);
5354                         continue;
5355                 }
5356                 slot = path->slots[0];
5357                 eb = path->nodes[0];
5358                 btrfs_item_key_to_cpu(eb, &found_key, slot);
5359                 item_size = btrfs_item_size_nr(eb, slot);
5360
5361                 ptr = btrfs_item_ptr(eb, slot,
5362                                      struct btrfs_dev_stats_item);
5363
5364                 for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++) {
5365                         if (item_size >= (1 + i) * sizeof(__le64))
5366                                 btrfs_dev_stat_set(device, i,
5367                                         btrfs_dev_stats_value(eb, ptr, i));
5368                         else
5369                                 btrfs_dev_stat_reset(device, i);
5370                 }
5371
5372                 device->dev_stats_valid = 1;
5373                 btrfs_dev_stat_print_on_load(device);
5374                 btrfs_release_path(path);
5375         }
5376         mutex_unlock(&fs_devices->device_list_mutex);
5377
5378 out:
5379         btrfs_free_path(path);
5380         return ret < 0 ? ret : 0;
5381 }
5382
5383 static int update_dev_stat_item(struct btrfs_trans_handle *trans,
5384                                 struct btrfs_root *dev_root,
5385                                 struct btrfs_device *device)
5386 {
5387         struct btrfs_path *path;
5388         struct btrfs_key key;
5389         struct extent_buffer *eb;
5390         struct btrfs_dev_stats_item *ptr;
5391         int ret;
5392         int i;
5393
5394         key.objectid = 0;
5395         key.type = BTRFS_DEV_STATS_KEY;
5396         key.offset = device->devid;
5397
5398         path = btrfs_alloc_path();
5399         BUG_ON(!path);
5400         ret = btrfs_search_slot(trans, dev_root, &key, path, -1, 1);
5401         if (ret < 0) {
5402                 printk_in_rcu(KERN_WARNING "btrfs: error %d while searching for dev_stats item for device %s!\n",
5403                               ret, rcu_str_deref(device->name));
5404                 goto out;
5405         }
5406
5407         if (ret == 0 &&
5408             btrfs_item_size_nr(path->nodes[0], path->slots[0]) < sizeof(*ptr)) {
5409                 /* need to delete old one and insert a new one */
5410                 ret = btrfs_del_item(trans, dev_root, path);
5411                 if (ret != 0) {
5412                         printk_in_rcu(KERN_WARNING "btrfs: delete too small dev_stats item for device %s failed %d!\n",
5413                                       rcu_str_deref(device->name), ret);
5414                         goto out;
5415                 }
5416                 ret = 1;
5417         }
5418
5419         if (ret == 1) {
5420                 /* need to insert a new item */
5421                 btrfs_release_path(path);
5422                 ret = btrfs_insert_empty_item(trans, dev_root, path,
5423                                               &key, sizeof(*ptr));
5424                 if (ret < 0) {
5425                         printk_in_rcu(KERN_WARNING "btrfs: insert dev_stats item for device %s failed %d!\n",
5426                                       rcu_str_deref(device->name), ret);
5427                         goto out;
5428                 }
5429         }
5430
5431         eb = path->nodes[0];
5432         ptr = btrfs_item_ptr(eb, path->slots[0], struct btrfs_dev_stats_item);
5433         for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++)
5434                 btrfs_set_dev_stats_value(eb, ptr, i,
5435                                           btrfs_dev_stat_read(device, i));
5436         btrfs_mark_buffer_dirty(eb);
5437
5438 out:
5439         btrfs_free_path(path);
5440         return ret;
5441 }
5442
5443 /*
5444  * called from commit_transaction. Writes all changed device stats to disk.
5445  */
5446 int btrfs_run_dev_stats(struct btrfs_trans_handle *trans,
5447                         struct btrfs_fs_info *fs_info)
5448 {
5449         struct btrfs_root *dev_root = fs_info->dev_root;
5450         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
5451         struct btrfs_device *device;
5452         int ret = 0;
5453
5454         mutex_lock(&fs_devices->device_list_mutex);
5455         list_for_each_entry(device, &fs_devices->devices, dev_list) {
5456                 if (!device->dev_stats_valid || !device->dev_stats_dirty)
5457                         continue;
5458
5459                 ret = update_dev_stat_item(trans, dev_root, device);
5460                 if (!ret)
5461                         device->dev_stats_dirty = 0;
5462         }
5463         mutex_unlock(&fs_devices->device_list_mutex);
5464
5465         return ret;
5466 }
5467
5468 void btrfs_dev_stat_inc_and_print(struct btrfs_device *dev, int index)
5469 {
5470         btrfs_dev_stat_inc(dev, index);
5471         btrfs_dev_stat_print_on_error(dev);
5472 }
5473
5474 void btrfs_dev_stat_print_on_error(struct btrfs_device *dev)
5475 {
5476         if (!dev->dev_stats_valid)
5477                 return;
5478         printk_ratelimited_in_rcu(KERN_ERR
5479                            "btrfs: bdev %s errs: wr %u, rd %u, flush %u, corrupt %u, gen %u\n",
5480                            rcu_str_deref(dev->name),
5481                            btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_WRITE_ERRS),
5482                            btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_READ_ERRS),
5483                            btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_FLUSH_ERRS),
5484                            btrfs_dev_stat_read(dev,
5485                                                BTRFS_DEV_STAT_CORRUPTION_ERRS),
5486                            btrfs_dev_stat_read(dev,
5487                                                BTRFS_DEV_STAT_GENERATION_ERRS));
5488 }
5489
5490 static void btrfs_dev_stat_print_on_load(struct btrfs_device *dev)
5491 {
5492         int i;
5493
5494         for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++)
5495                 if (btrfs_dev_stat_read(dev, i) != 0)
5496                         break;
5497         if (i == BTRFS_DEV_STAT_VALUES_MAX)
5498                 return; /* all values == 0, suppress message */
5499
5500         printk_in_rcu(KERN_INFO "btrfs: bdev %s errs: wr %u, rd %u, flush %u, corrupt %u, gen %u\n",
5501                rcu_str_deref(dev->name),
5502                btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_WRITE_ERRS),
5503                btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_READ_ERRS),
5504                btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_FLUSH_ERRS),
5505                btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_CORRUPTION_ERRS),
5506                btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_GENERATION_ERRS));
5507 }
5508
5509 int btrfs_get_dev_stats(struct btrfs_root *root,
5510                         struct btrfs_ioctl_get_dev_stats *stats)
5511 {
5512         struct btrfs_device *dev;
5513         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
5514         int i;
5515
5516         mutex_lock(&fs_devices->device_list_mutex);
5517         dev = btrfs_find_device(root->fs_info, stats->devid, NULL, NULL);
5518         mutex_unlock(&fs_devices->device_list_mutex);
5519
5520         if (!dev) {
5521                 printk(KERN_WARNING
5522                        "btrfs: get dev_stats failed, device not found\n");
5523                 return -ENODEV;
5524         } else if (!dev->dev_stats_valid) {
5525                 printk(KERN_WARNING
5526                        "btrfs: get dev_stats failed, not yet valid\n");
5527                 return -ENODEV;
5528         } else if (stats->flags & BTRFS_DEV_STATS_RESET) {
5529                 for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++) {
5530                         if (stats->nr_items > i)
5531                                 stats->values[i] =
5532                                         btrfs_dev_stat_read_and_reset(dev, i);
5533                         else
5534                                 btrfs_dev_stat_reset(dev, i);
5535                 }
5536         } else {
5537                 for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++)
5538                         if (stats->nr_items > i)
5539                                 stats->values[i] = btrfs_dev_stat_read(dev, i);
5540         }
5541         if (stats->nr_items > BTRFS_DEV_STAT_VALUES_MAX)
5542                 stats->nr_items = BTRFS_DEV_STAT_VALUES_MAX;
5543         return 0;
5544 }
5545
5546 int btrfs_scratch_superblock(struct btrfs_device *device)
5547 {
5548         struct buffer_head *bh;
5549         struct btrfs_super_block *disk_super;
5550
5551         bh = btrfs_read_dev_super(device->bdev);
5552         if (!bh)
5553                 return -EINVAL;
5554         disk_super = (struct btrfs_super_block *)bh->b_data;
5555
5556         memset(&disk_super->magic, 0, sizeof(disk_super->magic));
5557         set_buffer_dirty(bh);
5558         sync_dirty_buffer(bh);
5559         brelse(bh);
5560
5561         return 0;
5562 }