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 <asm/div64.h>
  26 #include "compat.h"
  27 #include "ctree.h"
  28 #include "extent_map.h"
  29 #include "disk-io.h"
  30 #include "transaction.h"
  31 #include "print-tree.h"
  32 #include "volumes.h"
  33 #include "async-thread.h"
  34
  35 struct map_lookup {
  36         u64 type;
  37         int io_align;
  38         int io_width;
  39         int stripe_len;
  40         int sector_size;
  41         int num_stripes;
  42         int sub_stripes;
  43         struct btrfs_bio_stripe stripes[];
  44 };
  45
  46 static int init_first_rw_device(struct btrfs_trans_handle *trans,
  47                                 struct btrfs_root *root,
  48                                 struct btrfs_device *device);
  49 static int btrfs_relocate_sys_chunks(struct btrfs_root *root);
  50
  51 #define map_lookup_size(n) (sizeof(struct map_lookup) + \
  52                             (sizeof(struct btrfs_bio_stripe) * (n)))
  53
  54 static DEFINE_MUTEX(uuid_mutex);
  55 static LIST_HEAD(fs_uuids);
  56
  57 void btrfs_lock_volumes(void)
  58 {
  59         mutex_lock(&uuid_mutex);
  60 }
  61
  62 void btrfs_unlock_volumes(void)
  63 {
  64         mutex_unlock(&uuid_mutex);
  65 }
  66
  67 static void lock_chunks(struct btrfs_root *root)
  68 {
  69         mutex_lock(&root->fs_info->chunk_mutex);
  70 }
  71
  72 static void unlock_chunks(struct btrfs_root *root)
  73 {
  74         mutex_unlock(&root->fs_info->chunk_mutex);
  75 }
  76
  77 static void free_fs_devices(struct btrfs_fs_devices *fs_devices)
  78 {
  79         struct btrfs_device *device;
  80         WARN_ON(fs_devices->opened);
  81         while (!list_empty(&fs_devices->devices)) {
  82                 device = list_entry(fs_devices->devices.next,
  83                                     struct btrfs_device, dev_list);
  84                 list_del(&device->dev_list);
  85                 kfree(device->name);
  86                 kfree(device);
  87         }
  88         kfree(fs_devices);
  89 }
  90
  91 int btrfs_cleanup_fs_uuids(void)
  92 {
  93         struct btrfs_fs_devices *fs_devices;
  94
  95         while (!list_empty(&fs_uuids)) {
  96                 fs_devices = list_entry(fs_uuids.next,
  97                                         struct btrfs_fs_devices, list);
  98                 list_del(&fs_devices->list);
  99                 free_fs_devices(fs_devices);
 100         }
 101         return 0;
 102 }
 103
 104 static noinline struct btrfs_device *__find_device(struct list_head *head,
 105                                                    u64 devid, u8 *uuid)
 106 {
 107         struct btrfs_device *dev;
 108
 109         list_for_each_entry(dev, head, dev_list) {
 110                 if (dev->devid == devid &&
 111                     (!uuid || !memcmp(dev->uuid, uuid, BTRFS_UUID_SIZE))) {
 112                         return dev;
 113                 }
 114         }
 115         return NULL;
 116 }
 117
 118 static noinline struct btrfs_fs_devices *find_fsid(u8 *fsid)
 119 {
 120         struct btrfs_fs_devices *fs_devices;
 121
 122         list_for_each_entry(fs_devices, &fs_uuids, list) {
 123                 if (memcmp(fsid, fs_devices->fsid, BTRFS_FSID_SIZE) == 0)
 124                         return fs_devices;
 125         }
 126         return NULL;
 127 }
 128
 129 static void requeue_list(struct btrfs_pending_bios *pending_bios,
 130                         struct bio *head, struct bio *tail)
 131 {
 132
 133         struct bio *old_head;
 134
 135         old_head = pending_bios->head;
 136         pending_bios->head = head;
 137         if (pending_bios->tail)
 138                 tail->bi_next = old_head;
 139         else
 140                 pending_bios->tail = tail;
 141 }
 142
 143 /*
 144  * we try to collect pending bios for a device so we don't get a large
 145  * number of procs sending bios down to the same device.  This greatly
 146  * improves the schedulers ability to collect and merge the bios.
 147  *
 148  * But, it also turns into a long list of bios to process and that is sure
 149  * to eventually make the worker thread block.  The solution here is to
 150  * make some progress and then put this work struct back at the end of
 151  * the list if the block device is congested.  This way, multiple devices
 152  * can make progress from a single worker thread.
 153  */
 154 static noinline int run_scheduled_bios(struct btrfs_device *device)
 155 {
 156         struct bio *pending;
 157         struct backing_dev_info *bdi;
 158         struct btrfs_fs_info *fs_info;
 159         struct btrfs_pending_bios *pending_bios;
 160         struct bio *tail;
 161         struct bio *cur;
 162         int again = 0;
 163         unsigned long num_run;
 164         unsigned long num_sync_run;
 165         unsigned long batch_run = 0;
 166         unsigned long limit;
 167         unsigned long last_waited = 0;
 168         int force_reg = 0;
 169
 170         bdi = blk_get_backing_dev_info(device->bdev);
 171         fs_info = device->dev_root->fs_info;
 172         limit = btrfs_async_submit_limit(fs_info);
 173         limit = limit * 2 / 3;
 174
 175         /* we want to make sure that every time we switch from the sync
 176          * list to the normal list, we unplug
 177          */
 178         num_sync_run = 0;
 179
 180 loop:
 181         spin_lock(&device->io_lock);
 182
 183 loop_lock:
 184         num_run = 0;
 185
 186         /* take all the bios off the list at once and process them
 187          * later on (without the lock held).  But, remember the
 188          * tail and other pointers so the bios can be properly reinserted
 189          * into the list if we hit congestion
 190          */
 191         if (!force_reg && device->pending_sync_bios.head) {
 192                 pending_bios = &device->pending_sync_bios;
 193                 force_reg = 1;
 194         } else {
 195                 pending_bios = &device->pending_bios;
 196                 force_reg = 0;
 197         }
 198
 199         pending = pending_bios->head;
 200         tail = pending_bios->tail;
 201         WARN_ON(pending && !tail);
 202
 203         /*
 204          * if pending was null this time around, no bios need processing
 205          * at all and we can stop.  Otherwise it'll loop back up again
 206          * and do an additional check so no bios are missed.
 207          *
 208          * device->running_pending is used to synchronize with the
 209          * schedule_bio code.
 210          */
 211         if (device->pending_sync_bios.head == NULL &&
 212             device->pending_bios.head == NULL) {
 213                 again = 0;
 214                 device->running_pending = 0;
 215         } else {
 216                 again = 1;
 217                 device->running_pending = 1;
 218         }
 219
 220         pending_bios->head = NULL;
 221         pending_bios->tail = NULL;
 222
 223         spin_unlock(&device->io_lock);
 224
 225         /*
 226          * if we're doing the regular priority list, make sure we unplug
 227          * for any high prio bios we've sent down
 228          */
 229         if (pending_bios == &device->pending_bios && num_sync_run > 0) {
 230                 num_sync_run = 0;
 231                 blk_run_backing_dev(bdi, NULL);
 232         }
 233
 234         while (pending) {
 235
 236                 rmb();
 237                 /* we want to work on both lists, but do more bios on the
 238                  * sync list than the regular list
 239                  */
 240                 if ((num_run > 32 &&
 241                     pending_bios != &device->pending_sync_bios &&
 242                     device->pending_sync_bios.head) ||
 243                    (num_run > 64 && pending_bios == &device->pending_sync_bios &&
 244                     device->pending_bios.head)) {
 245                         spin_lock(&device->io_lock);
 246                         requeue_list(pending_bios, pending, tail);
 247                         goto loop_lock;
 248                 }
 249
 250                 cur = pending;
 251                 pending = pending->bi_next;
 252                 cur->bi_next = NULL;
 253                 atomic_dec(&fs_info->nr_async_bios);
 254
 255                 if (atomic_read(&fs_info->nr_async_bios) < limit &&
 256                     waitqueue_active(&fs_info->async_submit_wait))
 257                         wake_up(&fs_info->async_submit_wait);
 258
 259                 BUG_ON(atomic_read(&cur->bi_cnt) == 0);
 260
 261                 if (bio_rw_flagged(cur, BIO_RW_SYNCIO))
 262                         num_sync_run++;
 263
 264                 submit_bio(cur->bi_rw, cur);
 265                 num_run++;
 266                 batch_run++;
 267                 if (need_resched()) {
 268                         if (num_sync_run) {
 269                                 blk_run_backing_dev(bdi, NULL);
 270                                 num_sync_run = 0;
 271                         }
 272                         cond_resched();
 273                 }
 274
 275                 /*
 276                  * we made progress, there is more work to do and the bdi
 277                  * is now congested.  Back off and let other work structs
 278                  * run instead
 279                  */
 280                 if (pending && bdi_write_congested(bdi) && batch_run > 8 &&
 281                     fs_info->fs_devices->open_devices > 1) {
 282                         struct io_context *ioc;
 283
 284                         ioc = current->io_context;
 285
 286                         /*
 287                          * the main goal here is that we don't want to
 288                          * block if we're going to be able to submit
 289                          * more requests without blocking.
 290                          *
 291                          * This code does two great things, it pokes into
 292                          * the elevator code from a filesystem _and_
 293                          * it makes assumptions about how batching works.
 294                          */
 295                         if (ioc && ioc->nr_batch_requests > 0 &&
 296                             time_before(jiffies, ioc->last_waited + HZ/50UL) &&
 297                             (last_waited == 0 ||
 298                              ioc->last_waited == last_waited)) {
 299                                 /*
 300                                  * we want to go through our batch of
 301                                  * requests and stop.  So, we copy out
 302                                  * the ioc->last_waited time and test
 303                                  * against it before looping
 304                                  */
 305                                 last_waited = ioc->last_waited;
 306                                 if (need_resched()) {
 307                                         if (num_sync_run) {
 308                                                 blk_run_backing_dev(bdi, NULL);
 309                                                 num_sync_run = 0;
 310                                         }
 311                                         cond_resched();
 312                                 }
 313                                 continue;
 314                         }
 315                         spin_lock(&device->io_lock);
 316                         requeue_list(pending_bios, pending, tail);
 317                         device->running_pending = 1;
 318
 319                         spin_unlock(&device->io_lock);
 320                         btrfs_requeue_work(&device->work);
 321                         goto done;
 322                 }
 323         }
 324
 325         if (num_sync_run) {
 326                 num_sync_run = 0;
 327                 blk_run_backing_dev(bdi, NULL);
 328         }
 329         /*
 330          * IO has already been through a long path to get here.  Checksumming,
 331          * async helper threads, perhaps compression.  We've done a pretty
 332          * good job of collecting a batch of IO and should just unplug
 333          * the device right away.
 334          *
 335          * This will help anyone who is waiting on the IO, they might have
 336          * already unplugged, but managed to do so before the bio they
 337          * cared about found its way down here.
 338          */
 339         blk_run_backing_dev(bdi, NULL);
 340
 341         cond_resched();
 342         if (again)
 343                 goto loop;
 344
 345         spin_lock(&device->io_lock);
 346         if (device->pending_bios.head || device->pending_sync_bios.head)
 347                 goto loop_lock;
 348         spin_unlock(&device->io_lock);
 349
 350 done:
 351         return 0;
 352 }
 353
 354 static void pending_bios_fn(struct btrfs_work *work)
 355 {
 356         struct btrfs_device *device;
 357
 358         device = container_of(work, struct btrfs_device, work);
 359         run_scheduled_bios(device);
 360 }
 361
 362 static noinline int device_list_add(const char *path,
 363                            struct btrfs_super_block *disk_super,
 364                            u64 devid, struct btrfs_fs_devices **fs_devices_ret)
 365 {
 366         struct btrfs_device *device;
 367         struct btrfs_fs_devices *fs_devices;
 368         u64 found_transid = btrfs_super_generation(disk_super);
 369         char *name;
 370
 371         fs_devices = find_fsid(disk_super->fsid);
 372         if (!fs_devices) {
 373                 fs_devices = kzalloc(sizeof(*fs_devices), GFP_NOFS);
 374                 if (!fs_devices)
 375                         return -ENOMEM;
 376                 INIT_LIST_HEAD(&fs_devices->devices);
 377                 INIT_LIST_HEAD(&fs_devices->alloc_list);
 378                 list_add(&fs_devices->list, &fs_uuids);
 379                 memcpy(fs_devices->fsid, disk_super->fsid, BTRFS_FSID_SIZE);
 380                 fs_devices->latest_devid = devid;
 381                 fs_devices->latest_trans = found_transid;
 382                 mutex_init(&fs_devices->device_list_mutex);
 383                 device = NULL;
 384         } else {
 385                 device = __find_device(&fs_devices->devices, devid,
 386                                        disk_super->dev_item.uuid);
 387         }
 388         if (!device) {
 389                 if (fs_devices->opened)
 390                         return -EBUSY;
 391
 392                 device = kzalloc(sizeof(*device), GFP_NOFS);
 393                 if (!device) {
 394                         /* we can safely leave the fs_devices entry around */
 395                         return -ENOMEM;
 396                 }
 397                 device->devid = devid;
 398                 device->work.func = pending_bios_fn;
 399                 memcpy(device->uuid, disk_super->dev_item.uuid,
 400                        BTRFS_UUID_SIZE);
 401                 device->barriers = 1;
 402                 spin_lock_init(&device->io_lock);
 403                 device->name = kstrdup(path, GFP_NOFS);
 404                 if (!device->name) {
 405                         kfree(device);
 406                         return -ENOMEM;
 407                 }
 408                 INIT_LIST_HEAD(&device->dev_alloc_list);
 409
 410                 mutex_lock(&fs_devices->device_list_mutex);
 411                 list_add(&device->dev_list, &fs_devices->devices);
 412                 mutex_unlock(&fs_devices->device_list_mutex);
 413
 414                 device->fs_devices = fs_devices;
 415                 fs_devices->num_devices++;
 416         } else if (strcmp(device->name, path)) {
 417                 name = kstrdup(path, GFP_NOFS);
 418                 if (!name)
 419                         return -ENOMEM;
 420                 kfree(device->name);
 421                 device->name = name;
 422         }
 423
 424         if (found_transid > fs_devices->latest_trans) {
 425                 fs_devices->latest_devid = devid;
 426                 fs_devices->latest_trans = found_transid;
 427         }
 428         *fs_devices_ret = fs_devices;
 429         return 0;
 430 }
 431
 432 static struct btrfs_fs_devices *clone_fs_devices(struct btrfs_fs_devices *orig)
 433 {
 434         struct btrfs_fs_devices *fs_devices;
 435         struct btrfs_device *device;
 436         struct btrfs_device *orig_dev;
 437
 438         fs_devices = kzalloc(sizeof(*fs_devices), GFP_NOFS);
 439         if (!fs_devices)
 440                 return ERR_PTR(-ENOMEM);
 441
 442         INIT_LIST_HEAD(&fs_devices->devices);
 443         INIT_LIST_HEAD(&fs_devices->alloc_list);
 444         INIT_LIST_HEAD(&fs_devices->list);
 445         mutex_init(&fs_devices->device_list_mutex);
 446         fs_devices->latest_devid = orig->latest_devid;
 447         fs_devices->latest_trans = orig->latest_trans;
 448         memcpy(fs_devices->fsid, orig->fsid, sizeof(fs_devices->fsid));
 449
 450         mutex_lock(&orig->device_list_mutex);
 451         list_for_each_entry(orig_dev, &orig->devices, dev_list) {
 452                 device = kzalloc(sizeof(*device), GFP_NOFS);
 453                 if (!device)
 454                         goto error;
 455
 456                 device->name = kstrdup(orig_dev->name, GFP_NOFS);
 457                 if (!device->name) {
 458                         kfree(device);
 459                         goto error;
 460                 }
 461
 462                 device->devid = orig_dev->devid;
 463                 device->work.func = pending_bios_fn;
 464                 memcpy(device->uuid, orig_dev->uuid, sizeof(device->uuid));
 465                 device->barriers = 1;
 466                 spin_lock_init(&device->io_lock);
 467                 INIT_LIST_HEAD(&device->dev_list);
 468                 INIT_LIST_HEAD(&device->dev_alloc_list);
 469
 470                 list_add(&device->dev_list, &fs_devices->devices);
 471                 device->fs_devices = fs_devices;
 472                 fs_devices->num_devices++;
 473         }
 474         mutex_unlock(&orig->device_list_mutex);
 475         return fs_devices;
 476 error:
 477         mutex_unlock(&orig->device_list_mutex);
 478         free_fs_devices(fs_devices);
 479         return ERR_PTR(-ENOMEM);
 480 }
 481
 482 int btrfs_close_extra_devices(struct btrfs_fs_devices *fs_devices)
 483 {
 484         struct btrfs_device *device, *next;
 485
 486         mutex_lock(&uuid_mutex);
 487 again:
 488         mutex_lock(&fs_devices->device_list_mutex);
 489         list_for_each_entry_safe(device, next, &fs_devices->devices, dev_list) {
 490                 if (device->in_fs_metadata)
 491                         continue;
 492
 493                 if (device->bdev) {
 494                         close_bdev_exclusive(device->bdev, device->mode);
 495                         device->bdev = NULL;
 496                         fs_devices->open_devices--;
 497                 }
 498                 if (device->writeable) {
 499                         list_del_init(&device->dev_alloc_list);
 500                         device->writeable = 0;
 501                         fs_devices->rw_devices--;
 502                 }
 503                 list_del_init(&device->dev_list);
 504                 fs_devices->num_devices--;
 505                 kfree(device->name);
 506                 kfree(device);
 507         }
 508         mutex_unlock(&fs_devices->device_list_mutex);
 509
 510         if (fs_devices->seed) {
 511                 fs_devices = fs_devices->seed;
 512                 goto again;
 513         }
 514
 515         mutex_unlock(&uuid_mutex);
 516         return 0;
 517 }
 518
 519 static int __btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
 520 {
 521         struct btrfs_device *device;
 522
 523         if (--fs_devices->opened > 0)
 524                 return 0;
 525
 526         list_for_each_entry(device, &fs_devices->devices, dev_list) {
 527                 if (device->bdev) {
 528                         close_bdev_exclusive(device->bdev, device->mode);
 529                         fs_devices->open_devices--;
 530                 }
 531                 if (device->writeable) {
 532                         list_del_init(&device->dev_alloc_list);
 533                         fs_devices->rw_devices--;
 534                 }
 535
 536                 device->bdev = NULL;
 537                 device->writeable = 0;
 538                 device->in_fs_metadata = 0;
 539         }
 540         WARN_ON(fs_devices->open_devices);
 541         WARN_ON(fs_devices->rw_devices);
 542         fs_devices->opened = 0;
 543         fs_devices->seeding = 0;
 544
 545         return 0;
 546 }
 547
 548 int btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
 549 {
 550         struct btrfs_fs_devices *seed_devices = NULL;
 551         int ret;
 552
 553         mutex_lock(&uuid_mutex);
 554         ret = __btrfs_close_devices(fs_devices);
 555         if (!fs_devices->opened) {
 556                 seed_devices = fs_devices->seed;
 557                 fs_devices->seed = NULL;
 558         }
 559         mutex_unlock(&uuid_mutex);
 560
 561         while (seed_devices) {
 562                 fs_devices = seed_devices;
 563                 seed_devices = fs_devices->seed;
 564                 __btrfs_close_devices(fs_devices);
 565                 free_fs_devices(fs_devices);
 566         }
 567         return ret;
 568 }
 569
 570 static int __btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
 571                                 fmode_t flags, void *holder)
 572 {
 573         struct block_device *bdev;
 574         struct list_head *head = &fs_devices->devices;
 575         struct btrfs_device *device;
 576         struct block_device *latest_bdev = NULL;
 577         struct buffer_head *bh;
 578         struct btrfs_super_block *disk_super;
 579         u64 latest_devid = 0;
 580         u64 latest_transid = 0;
 581         u64 devid;
 582         int seeding = 1;
 583         int ret = 0;
 584
 585         list_for_each_entry(device, head, dev_list) {
 586                 if (device->bdev)
 587                         continue;
 588                 if (!device->name)
 589                         continue;
 590
 591                 bdev = open_bdev_exclusive(device->name, flags, holder);
 592                 if (IS_ERR(bdev)) {
 593                         printk(KERN_INFO "open %s failed\n", device->name);
 594                         goto error;
 595                 }
 596                 set_blocksize(bdev, 4096);
 597
 598                 bh = btrfs_read_dev_super(bdev);
 599                 if (!bh)
 600                         goto error_close;
 601
 602                 disk_super = (struct btrfs_super_block *)bh->b_data;
 603                 devid = btrfs_stack_device_id(&disk_super->dev_item);
 604                 if (devid != device->devid)
 605                         goto error_brelse;
 606
 607                 if (memcmp(device->uuid, disk_super->dev_item.uuid,
 608                            BTRFS_UUID_SIZE))
 609                         goto error_brelse;
 610
 611                 device->generation = btrfs_super_generation(disk_super);
 612                 if (!latest_transid || device->generation > latest_transid) {
 613                         latest_devid = devid;
 614                         latest_transid = device->generation;
 615                         latest_bdev = bdev;
 616                 }
 617
 618                 if (btrfs_super_flags(disk_super) & BTRFS_SUPER_FLAG_SEEDING) {
 619                         device->writeable = 0;
 620                 } else {
 621                         device->writeable = !bdev_read_only(bdev);
 622                         seeding = 0;
 623                 }
 624
 625                 device->bdev = bdev;
 626                 device->in_fs_metadata = 0;
 627                 device->mode = flags;
 628
 629                 if (!blk_queue_nonrot(bdev_get_queue(bdev)))
 630                         fs_devices->rotating = 1;
 631
 632                 fs_devices->open_devices++;
 633                 if (device->writeable) {
 634                         fs_devices->rw_devices++;
 635                         list_add(&device->dev_alloc_list,
 636                                  &fs_devices->alloc_list);
 637                 }
 638                 continue;
 639
 640 error_brelse:
 641                 brelse(bh);
 642 error_close:
 643                 close_bdev_exclusive(bdev, FMODE_READ);
 644 error:
 645                 continue;
 646         }
 647         if (fs_devices->open_devices == 0) {
 648                 ret = -EIO;
 649                 goto out;
 650         }
 651         fs_devices->seeding = seeding;
 652         fs_devices->opened = 1;
 653         fs_devices->latest_bdev = latest_bdev;
 654         fs_devices->latest_devid = latest_devid;
 655         fs_devices->latest_trans = latest_transid;
 656         fs_devices->total_rw_bytes = 0;
 657 out:
 658         return ret;
 659 }
 660
 661 int btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
 662                        fmode_t flags, void *holder)
 663 {
 664         int ret;
 665
 666         mutex_lock(&uuid_mutex);
 667         if (fs_devices->opened) {
 668                 fs_devices->opened++;
 669                 ret = 0;
 670         } else {
 671                 ret = __btrfs_open_devices(fs_devices, flags, holder);
 672         }
 673         mutex_unlock(&uuid_mutex);
 674         return ret;
 675 }
 676
 677 int btrfs_scan_one_device(const char *path, fmode_t flags, void *holder,
 678                           struct btrfs_fs_devices **fs_devices_ret)
 679 {
 680         struct btrfs_super_block *disk_super;
 681         struct block_device *bdev;
 682         struct buffer_head *bh;
 683         int ret;
 684         u64 devid;
 685         u64 transid;
 686
 687         mutex_lock(&uuid_mutex);
 688
 689         bdev = open_bdev_exclusive(path, flags, holder);
 690
 691         if (IS_ERR(bdev)) {
 692                 ret = PTR_ERR(bdev);
 693                 goto error;
 694         }
 695
 696         ret = set_blocksize(bdev, 4096);
 697         if (ret)
 698                 goto error_close;
 699         bh = btrfs_read_dev_super(bdev);
 700         if (!bh) {
 701                 ret = -EIO;
 702                 goto error_close;
 703         }
 704         disk_super = (struct btrfs_super_block *)bh->b_data;
 705         devid = btrfs_stack_device_id(&disk_super->dev_item);
 706         transid = btrfs_super_generation(disk_super);
 707         if (disk_super->label[0])
 708                 printk(KERN_INFO "device label %s ", disk_super->label);
 709         else {
 710                 /* FIXME, make a readl uuid parser */
 711                 printk(KERN_INFO "device fsid %llx-%llx ",
 712                        *(unsigned long long *)disk_super->fsid,
 713                        *(unsigned long long *)(disk_super->fsid + 8));
 714         }
 715         printk(KERN_CONT "devid %llu transid %llu %s\n",
 716                (unsigned long long)devid, (unsigned long long)transid, path);
 717         ret = device_list_add(path, disk_super, devid, fs_devices_ret);
 718
 719         brelse(bh);
 720 error_close:
 721         close_bdev_exclusive(bdev, flags);
 722 error:
 723         mutex_unlock(&uuid_mutex);
 724         return ret;
 725 }
 726
 727 /*
 728  * this uses a pretty simple search, the expectation is that it is
 729  * called very infrequently and that a given device has a small number
 730  * of extents
 731  */
 732 int find_free_dev_extent(struct btrfs_trans_handle *trans,
 733                          struct btrfs_device *device, u64 num_bytes,
 734                          u64 *start, u64 *max_avail)
 735 {
 736         struct btrfs_key key;
 737         struct btrfs_root *root = device->dev_root;
 738         struct btrfs_dev_extent *dev_extent = NULL;
 739         struct btrfs_path *path;
 740         u64 hole_size = 0;
 741         u64 last_byte = 0;
 742         u64 search_start = 0;
 743         u64 search_end = device->total_bytes;
 744         int ret;
 745         int slot = 0;
 746         int start_found;
 747         struct extent_buffer *l;
 748
 749         path = btrfs_alloc_path();
 750         if (!path)
 751                 return -ENOMEM;
 752         path->reada = 2;
 753         start_found = 0;
 754
 755         /* FIXME use last free of some kind */
 756
 757         /* we don't want to overwrite the superblock on the drive,
 758          * so we make sure to start at an offset of at least 1MB
 759          */
 760         search_start = max((u64)1024 * 1024, search_start);
 761
 762         if (root->fs_info->alloc_start + num_bytes <= device->total_bytes)
 763                 search_start = max(root->fs_info->alloc_start, search_start);
 764
 765         key.objectid = device->devid;
 766         key.offset = search_start;
 767         key.type = BTRFS_DEV_EXTENT_KEY;
 768         ret = btrfs_search_slot(trans, root, &key, path, 0, 0);
 769         if (ret < 0)
 770                 goto error;
 771         if (ret > 0) {
 772                 ret = btrfs_previous_item(root, path, key.objectid, key.type);
 773                 if (ret < 0)
 774                         goto error;
 775                 if (ret > 0)
 776                         start_found = 1;
 777         }
 778         l = path->nodes[0];
 779         btrfs_item_key_to_cpu(l, &key, path->slots[0]);
 780         while (1) {
 781                 l = path->nodes[0];
 782                 slot = path->slots[0];
 783                 if (slot >= btrfs_header_nritems(l)) {
 784                         ret = btrfs_next_leaf(root, path);
 785                         if (ret == 0)
 786                                 continue;
 787                         if (ret < 0)
 788                                 goto error;
 789 no_more_items:
 790                         if (!start_found) {
 791                                 if (search_start >= search_end) {
 792                                         ret = -ENOSPC;
 793                                         goto error;
 794                                 }
 795                                 *start = search_start;
 796                                 start_found = 1;
 797                                 goto check_pending;
 798                         }
 799                         *start = last_byte > search_start ?
 800                                 last_byte : search_start;
 801                         if (search_end <= *start) {
 802                                 ret = -ENOSPC;
 803                                 goto error;
 804                         }
 805                         goto check_pending;
 806                 }
 807                 btrfs_item_key_to_cpu(l, &key, slot);
 808
 809                 if (key.objectid < device->devid)
 810                         goto next;
 811
 812                 if (key.objectid > device->devid)
 813                         goto no_more_items;
 814
 815                 if (key.offset >= search_start && key.offset > last_byte &&
 816                     start_found) {
 817                         if (last_byte < search_start)
 818                                 last_byte = search_start;
 819                         hole_size = key.offset - last_byte;
 820
 821                         if (hole_size > *max_avail)
 822                                 *max_avail = hole_size;
 823
 824                         if (key.offset > last_byte &&
 825                             hole_size >= num_bytes) {
 826                                 *start = last_byte;
 827                                 goto check_pending;
 828                         }
 829                 }
 830                 if (btrfs_key_type(&key) != BTRFS_DEV_EXTENT_KEY)
 831                         goto next;
 832
 833                 start_found = 1;
 834                 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
 835                 last_byte = key.offset + btrfs_dev_extent_length(l, dev_extent);
 836 next:
 837                 path->slots[0]++;
 838                 cond_resched();
 839         }
 840 check_pending:
 841         /* we have to make sure we didn't find an extent that has already
 842          * been allocated by the map tree or the original allocation
 843          */
 844         BUG_ON(*start < search_start);
 845
 846         if (*start + num_bytes > search_end) {
 847                 ret = -ENOSPC;
 848                 goto error;
 849         }
 850         /* check for pending inserts here */
 851         ret = 0;
 852
 853 error:
 854         btrfs_free_path(path);
 855         return ret;
 856 }
 857
 858 static int btrfs_free_dev_extent(struct btrfs_trans_handle *trans,
 859                           struct btrfs_device *device,
 860                           u64 start)
 861 {
 862         int ret;
 863         struct btrfs_path *path;
 864         struct btrfs_root *root = device->dev_root;
 865         struct btrfs_key key;
 866         struct btrfs_key found_key;
 867         struct extent_buffer *leaf = NULL;
 868         struct btrfs_dev_extent *extent = NULL;
 869
 870         path = btrfs_alloc_path();
 871         if (!path)
 872                 return -ENOMEM;
 873
 874         key.objectid = device->devid;
 875         key.offset = start;
 876         key.type = BTRFS_DEV_EXTENT_KEY;
 877
 878         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
 879         if (ret > 0) {
 880                 ret = btrfs_previous_item(root, path, key.objectid,
 881                                           BTRFS_DEV_EXTENT_KEY);
 882                 BUG_ON(ret);
 883                 leaf = path->nodes[0];
 884                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
 885                 extent = btrfs_item_ptr(leaf, path->slots[0],
 886                                         struct btrfs_dev_extent);
 887                 BUG_ON(found_key.offset > start || found_key.offset +
 888                        btrfs_dev_extent_length(leaf, extent) < start);
 889                 ret = 0;
 890         } else if (ret == 0) {
 891                 leaf = path->nodes[0];
 892                 extent = btrfs_item_ptr(leaf, path->slots[0],
 893                                         struct btrfs_dev_extent);
 894         }
 895         BUG_ON(ret);
 896
 897         if (device->bytes_used > 0)
 898                 device->bytes_used -= btrfs_dev_extent_length(leaf, extent);
 899         ret = btrfs_del_item(trans, root, path);
 900         BUG_ON(ret);
 901
 902         btrfs_free_path(path);
 903         return ret;
 904 }
 905
 906 int btrfs_alloc_dev_extent(struct btrfs_trans_handle *trans,
 907                            struct btrfs_device *device,
 908                            u64 chunk_tree, u64 chunk_objectid,
 909                            u64 chunk_offset, u64 start, u64 num_bytes)
 910 {
 911         int ret;
 912         struct btrfs_path *path;
 913         struct btrfs_root *root = device->dev_root;
 914         struct btrfs_dev_extent *extent;
 915         struct extent_buffer *leaf;
 916         struct btrfs_key key;
 917
 918         WARN_ON(!device->in_fs_metadata);
 919         path = btrfs_alloc_path();
 920         if (!path)
 921                 return -ENOMEM;
 922
 923         key.objectid = device->devid;
 924         key.offset = start;
 925         key.type = BTRFS_DEV_EXTENT_KEY;
 926         ret = btrfs_insert_empty_item(trans, root, path, &key,
 927                                       sizeof(*extent));
 928         BUG_ON(ret);
 929
 930         leaf = path->nodes[0];
 931         extent = btrfs_item_ptr(leaf, path->slots[0],
 932                                 struct btrfs_dev_extent);
 933         btrfs_set_dev_extent_chunk_tree(leaf, extent, chunk_tree);
 934         btrfs_set_dev_extent_chunk_objectid(leaf, extent, chunk_objectid);
 935         btrfs_set_dev_extent_chunk_offset(leaf, extent, chunk_offset);
 936
 937         write_extent_buffer(leaf, root->fs_info->chunk_tree_uuid,
 938                     (unsigned long)btrfs_dev_extent_chunk_tree_uuid(extent),
 939                     BTRFS_UUID_SIZE);
 940
 941         btrfs_set_dev_extent_length(leaf, extent, num_bytes);
 942         btrfs_mark_buffer_dirty(leaf);
 943         btrfs_free_path(path);
 944         return ret;
 945 }
 946
 947 static noinline int find_next_chunk(struct btrfs_root *root,
 948                                     u64 objectid, u64 *offset)
 949 {
 950         struct btrfs_path *path;
 951         int ret;
 952         struct btrfs_key key;
 953         struct btrfs_chunk *chunk;
 954         struct btrfs_key found_key;
 955
 956         path = btrfs_alloc_path();
 957         BUG_ON(!path);
 958
 959         key.objectid = objectid;
 960         key.offset = (u64)-1;
 961         key.type = BTRFS_CHUNK_ITEM_KEY;
 962
 963         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 964         if (ret < 0)
 965                 goto error;
 966
 967         BUG_ON(ret == 0);
 968
 969         ret = btrfs_previous_item(root, path, 0, BTRFS_CHUNK_ITEM_KEY);
 970         if (ret) {
 971                 *offset = 0;
 972         } else {
 973                 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
 974                                       path->slots[0]);
 975                 if (found_key.objectid != objectid)
 976                         *offset = 0;
 977                 else {
 978                         chunk = btrfs_item_ptr(path->nodes[0], path->slots[0],
 979                                                struct btrfs_chunk);
 980                         *offset = found_key.offset +
 981                                 btrfs_chunk_length(path->nodes[0], chunk);
 982                 }
 983         }
 984         ret = 0;
 985 error:
 986         btrfs_free_path(path);
 987         return ret;
 988 }
 989
 990 static noinline int find_next_devid(struct btrfs_root *root, u64 *objectid)
 991 {
 992         int ret;
 993         struct btrfs_key key;
 994         struct btrfs_key found_key;
 995         struct btrfs_path *path;
 996
 997         root = root->fs_info->chunk_root;
 998
 999         path = btrfs_alloc_path();
1000         if (!path)
1001                 return -ENOMEM;
1002
1003         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1004         key.type = BTRFS_DEV_ITEM_KEY;
1005         key.offset = (u64)-1;
1006
1007         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1008         if (ret < 0)
1009                 goto error;
1010
1011         BUG_ON(ret == 0);
1012
1013         ret = btrfs_previous_item(root, path, BTRFS_DEV_ITEMS_OBJECTID,
1014                                   BTRFS_DEV_ITEM_KEY);
1015         if (ret) {
1016                 *objectid = 1;
1017         } else {
1018                 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
1019                                       path->slots[0]);
1020                 *objectid = found_key.offset + 1;
1021         }
1022         ret = 0;
1023 error:
1024         btrfs_free_path(path);
1025         return ret;
1026 }
1027
1028 /*
1029  * the device information is stored in the chunk root
1030  * the btrfs_device struct should be fully filled in
1031  */
1032 int btrfs_add_device(struct btrfs_trans_handle *trans,
1033                      struct btrfs_root *root,
1034                      struct btrfs_device *device)
1035 {
1036         int ret;
1037         struct btrfs_path *path;
1038         struct btrfs_dev_item *dev_item;
1039         struct extent_buffer *leaf;
1040         struct btrfs_key key;
1041         unsigned long ptr;
1042
1043         root = root->fs_info->chunk_root;
1044
1045         path = btrfs_alloc_path();
1046         if (!path)
1047                 return -ENOMEM;
1048
1049         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1050         key.type = BTRFS_DEV_ITEM_KEY;
1051         key.offset = device->devid;
1052
1053         ret = btrfs_insert_empty_item(trans, root, path, &key,
1054                                       sizeof(*dev_item));
1055         if (ret)
1056                 goto out;
1057
1058         leaf = path->nodes[0];
1059         dev_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dev_item);
1060
1061         btrfs_set_device_id(leaf, dev_item, device->devid);
1062         btrfs_set_device_generation(leaf, dev_item, 0);
1063         btrfs_set_device_type(leaf, dev_item, device->type);
1064         btrfs_set_device_io_align(leaf, dev_item, device->io_align);
1065         btrfs_set_device_io_width(leaf, dev_item, device->io_width);
1066         btrfs_set_device_sector_size(leaf, dev_item, device->sector_size);
1067         btrfs_set_device_total_bytes(leaf, dev_item, device->total_bytes);
1068         btrfs_set_device_bytes_used(leaf, dev_item, device->bytes_used);
1069         btrfs_set_device_group(leaf, dev_item, 0);
1070         btrfs_set_device_seek_speed(leaf, dev_item, 0);
1071         btrfs_set_device_bandwidth(leaf, dev_item, 0);
1072         btrfs_set_device_start_offset(leaf, dev_item, 0);
1073
1074         ptr = (unsigned long)btrfs_device_uuid(dev_item);
1075         write_extent_buffer(leaf, device->uuid, ptr, BTRFS_UUID_SIZE);
1076         ptr = (unsigned long)btrfs_device_fsid(dev_item);
1077         write_extent_buffer(leaf, root->fs_info->fsid, ptr, BTRFS_UUID_SIZE);
1078         btrfs_mark_buffer_dirty(leaf);
1079
1080         ret = 0;
1081 out:
1082         btrfs_free_path(path);
1083         return ret;
1084 }
1085
1086 static int btrfs_rm_dev_item(struct btrfs_root *root,
1087                              struct btrfs_device *device)
1088 {
1089         int ret;
1090         struct btrfs_path *path;
1091         struct btrfs_key key;
1092         struct btrfs_trans_handle *trans;
1093
1094         root = root->fs_info->chunk_root;
1095
1096         path = btrfs_alloc_path();
1097         if (!path)
1098                 return -ENOMEM;
1099
1100         trans = btrfs_start_transaction(root, 0);
1101         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1102         key.type = BTRFS_DEV_ITEM_KEY;
1103         key.offset = device->devid;
1104         lock_chunks(root);
1105
1106         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1107         if (ret < 0)
1108                 goto out;
1109
1110         if (ret > 0) {
1111                 ret = -ENOENT;
1112                 goto out;
1113         }
1114
1115         ret = btrfs_del_item(trans, root, path);
1116         if (ret)
1117                 goto out;
1118 out:
1119         btrfs_free_path(path);
1120         unlock_chunks(root);
1121         btrfs_commit_transaction(trans, root);
1122         return ret;
1123 }
1124
1125 int btrfs_rm_device(struct btrfs_root *root, char *device_path)
1126 {
1127         struct btrfs_device *device;
1128         struct btrfs_device *next_device;
1129         struct block_device *bdev;
1130         struct buffer_head *bh = NULL;
1131         struct btrfs_super_block *disk_super;
1132         u64 all_avail;
1133         u64 devid;
1134         u64 num_devices;
1135         u8 *dev_uuid;
1136         int ret = 0;
1137
1138         mutex_lock(&uuid_mutex);
1139         mutex_lock(&root->fs_info->volume_mutex);
1140
1141         all_avail = root->fs_info->avail_data_alloc_bits |
1142                 root->fs_info->avail_system_alloc_bits |
1143                 root->fs_info->avail_metadata_alloc_bits;
1144
1145         if ((all_avail & BTRFS_BLOCK_GROUP_RAID10) &&
1146             root->fs_info->fs_devices->num_devices <= 4) {
1147                 printk(KERN_ERR "btrfs: unable to go below four devices "
1148                        "on raid10\n");
1149                 ret = -EINVAL;
1150                 goto out;
1151         }
1152
1153         if ((all_avail & BTRFS_BLOCK_GROUP_RAID1) &&
1154             root->fs_info->fs_devices->num_devices <= 2) {
1155                 printk(KERN_ERR "btrfs: unable to go below two "
1156                        "devices on raid1\n");
1157                 ret = -EINVAL;
1158                 goto out;
1159         }
1160
1161         if (strcmp(device_path, "missing") == 0) {
1162                 struct list_head *devices;
1163                 struct btrfs_device *tmp;
1164
1165                 device = NULL;
1166                 devices = &root->fs_info->fs_devices->devices;
1167                 mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
1168                 list_for_each_entry(tmp, devices, dev_list) {
1169                         if (tmp->in_fs_metadata && !tmp->bdev) {
1170                                 device = tmp;
1171                                 break;
1172                         }
1173                 }
1174                 mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1175                 bdev = NULL;
1176                 bh = NULL;
1177                 disk_super = NULL;
1178                 if (!device) {
1179                         printk(KERN_ERR "btrfs: no missing devices found to "
1180                                "remove\n");
1181                         goto out;
1182                 }
1183         } else {
1184                 bdev = open_bdev_exclusive(device_path, FMODE_READ,
1185                                       root->fs_info->bdev_holder);
1186                 if (IS_ERR(bdev)) {
1187                         ret = PTR_ERR(bdev);
1188                         goto out;
1189                 }
1190
1191                 set_blocksize(bdev, 4096);
1192                 bh = btrfs_read_dev_super(bdev);
1193                 if (!bh) {
1194                         ret = -EIO;
1195                         goto error_close;
1196                 }
1197                 disk_super = (struct btrfs_super_block *)bh->b_data;
1198                 devid = btrfs_stack_device_id(&disk_super->dev_item);
1199                 dev_uuid = disk_super->dev_item.uuid;
1200                 device = btrfs_find_device(root, devid, dev_uuid,
1201                                            disk_super->fsid);
1202                 if (!device) {
1203                         ret = -ENOENT;
1204                         goto error_brelse;
1205                 }
1206         }
1207
1208         if (device->writeable && root->fs_info->fs_devices->rw_devices == 1) {
1209                 printk(KERN_ERR "btrfs: unable to remove the only writeable "
1210                        "device\n");
1211                 ret = -EINVAL;
1212                 goto error_brelse;
1213         }
1214
1215         if (device->writeable) {
1216                 list_del_init(&device->dev_alloc_list);
1217                 root->fs_info->fs_devices->rw_devices--;
1218         }
1219
1220         ret = btrfs_shrink_device(device, 0);
1221         if (ret)
1222                 goto error_brelse;
1223
1224         ret = btrfs_rm_dev_item(root->fs_info->chunk_root, device);
1225         if (ret)
1226                 goto error_brelse;
1227
1228         device->in_fs_metadata = 0;
1229
1230         /*
1231          * the device list mutex makes sure that we don't change
1232          * the device list while someone else is writing out all
1233          * the device supers.
1234          */
1235         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
1236         list_del_init(&device->dev_list);
1237         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1238
1239         device->fs_devices->num_devices--;
1240
1241         next_device = list_entry(root->fs_info->fs_devices->devices.next,
1242                                  struct btrfs_device, dev_list);
1243         if (device->bdev == root->fs_info->sb->s_bdev)
1244                 root->fs_info->sb->s_bdev = next_device->bdev;
1245         if (device->bdev == root->fs_info->fs_devices->latest_bdev)
1246                 root->fs_info->fs_devices->latest_bdev = next_device->bdev;
1247
1248         if (device->bdev) {
1249                 close_bdev_exclusive(device->bdev, device->mode);
1250                 device->bdev = NULL;
1251                 device->fs_devices->open_devices--;
1252         }
1253
1254         num_devices = btrfs_super_num_devices(&root->fs_info->super_copy) - 1;
1255         btrfs_set_super_num_devices(&root->fs_info->super_copy, num_devices);
1256
1257         if (device->fs_devices->open_devices == 0) {
1258                 struct btrfs_fs_devices *fs_devices;
1259                 fs_devices = root->fs_info->fs_devices;
1260                 while (fs_devices) {
1261                         if (fs_devices->seed == device->fs_devices)
1262                                 break;
1263                         fs_devices = fs_devices->seed;
1264                 }
1265                 fs_devices->seed = device->fs_devices->seed;
1266                 device->fs_devices->seed = NULL;
1267                 __btrfs_close_devices(device->fs_devices);
1268                 free_fs_devices(device->fs_devices);
1269         }
1270
1271         /*
1272          * at this point, the device is zero sized.  We want to
1273          * remove it from the devices list and zero out the old super
1274          */
1275         if (device->writeable) {
1276                 /* make sure this device isn't detected as part of
1277                  * the FS anymore
1278                  */
1279                 memset(&disk_super->magic, 0, sizeof(disk_super->magic));
1280                 set_buffer_dirty(bh);
1281                 sync_dirty_buffer(bh);
1282         }
1283
1284         kfree(device->name);
1285         kfree(device);
1286         ret = 0;
1287
1288 error_brelse:
1289         brelse(bh);
1290 error_close:
1291         if (bdev)
1292                 close_bdev_exclusive(bdev, FMODE_READ);
1293 out:
1294         mutex_unlock(&root->fs_info->volume_mutex);
1295         mutex_unlock(&uuid_mutex);
1296         return ret;
1297 }
1298
1299 /*
1300  * does all the dirty work required for changing file system's UUID.
1301  */
1302 static int btrfs_prepare_sprout(struct btrfs_trans_handle *trans,
1303                                 struct btrfs_root *root)
1304 {
1305         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
1306         struct btrfs_fs_devices *old_devices;
1307         struct btrfs_fs_devices *seed_devices;
1308         struct btrfs_super_block *disk_super = &root->fs_info->super_copy;
1309         struct btrfs_device *device;
1310         u64 super_flags;
1311
1312         BUG_ON(!mutex_is_locked(&uuid_mutex));
1313         if (!fs_devices->seeding)
1314                 return -EINVAL;
1315
1316         seed_devices = kzalloc(sizeof(*fs_devices), GFP_NOFS);
1317         if (!seed_devices)
1318                 return -ENOMEM;
1319
1320         old_devices = clone_fs_devices(fs_devices);
1321         if (IS_ERR(old_devices)) {
1322                 kfree(seed_devices);
1323                 return PTR_ERR(old_devices);
1324         }
1325
1326         list_add(&old_devices->list, &fs_uuids);
1327
1328         memcpy(seed_devices, fs_devices, sizeof(*seed_devices));
1329         seed_devices->opened = 1;
1330         INIT_LIST_HEAD(&seed_devices->devices);
1331         INIT_LIST_HEAD(&seed_devices->alloc_list);
1332         mutex_init(&seed_devices->device_list_mutex);
1333         list_splice_init(&fs_devices->devices, &seed_devices->devices);
1334         list_splice_init(&fs_devices->alloc_list, &seed_devices->alloc_list);
1335         list_for_each_entry(device, &seed_devices->devices, dev_list) {
1336                 device->fs_devices = seed_devices;
1337         }
1338
1339         fs_devices->seeding = 0;
1340         fs_devices->num_devices = 0;
1341         fs_devices->open_devices = 0;
1342         fs_devices->seed = seed_devices;
1343
1344         generate_random_uuid(fs_devices->fsid);
1345         memcpy(root->fs_info->fsid, fs_devices->fsid, BTRFS_FSID_SIZE);
1346         memcpy(disk_super->fsid, fs_devices->fsid, BTRFS_FSID_SIZE);
1347         super_flags = btrfs_super_flags(disk_super) &
1348                       ~BTRFS_SUPER_FLAG_SEEDING;
1349         btrfs_set_super_flags(disk_super, super_flags);
1350
1351         return 0;
1352 }
1353
1354 /*
1355  * strore the expected generation for seed devices in device items.
1356  */
1357 static int btrfs_finish_sprout(struct btrfs_trans_handle *trans,
1358                                struct btrfs_root *root)
1359 {
1360         struct btrfs_path *path;
1361         struct extent_buffer *leaf;
1362         struct btrfs_dev_item *dev_item;
1363         struct btrfs_device *device;
1364         struct btrfs_key key;
1365         u8 fs_uuid[BTRFS_UUID_SIZE];
1366         u8 dev_uuid[BTRFS_UUID_SIZE];
1367         u64 devid;
1368         int ret;
1369
1370         path = btrfs_alloc_path();
1371         if (!path)
1372                 return -ENOMEM;
1373
1374         root = root->fs_info->chunk_root;
1375         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1376         key.offset = 0;
1377         key.type = BTRFS_DEV_ITEM_KEY;
1378
1379         while (1) {
1380                 ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
1381                 if (ret < 0)
1382                         goto error;
1383
1384                 leaf = path->nodes[0];
1385 next_slot:
1386                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
1387                         ret = btrfs_next_leaf(root, path);
1388                         if (ret > 0)
1389                                 break;
1390                         if (ret < 0)
1391                                 goto error;
1392                         leaf = path->nodes[0];
1393                         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1394                         btrfs_release_path(root, path);
1395                         continue;
1396                 }
1397
1398                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1399                 if (key.objectid != BTRFS_DEV_ITEMS_OBJECTID ||
1400                     key.type != BTRFS_DEV_ITEM_KEY)
1401                         break;
1402
1403                 dev_item = btrfs_item_ptr(leaf, path->slots[0],
1404                                           struct btrfs_dev_item);
1405                 devid = btrfs_device_id(leaf, dev_item);
1406                 read_extent_buffer(leaf, dev_uuid,
1407                                    (unsigned long)btrfs_device_uuid(dev_item),
1408                                    BTRFS_UUID_SIZE);
1409                 read_extent_buffer(leaf, fs_uuid,
1410                                    (unsigned long)btrfs_device_fsid(dev_item),
1411                                    BTRFS_UUID_SIZE);
1412                 device = btrfs_find_device(root, devid, dev_uuid, fs_uuid);
1413                 BUG_ON(!device);
1414
1415                 if (device->fs_devices->seeding) {
1416                         btrfs_set_device_generation(leaf, dev_item,
1417                                                     device->generation);
1418                         btrfs_mark_buffer_dirty(leaf);
1419                 }
1420
1421                 path->slots[0]++;
1422                 goto next_slot;
1423         }
1424         ret = 0;
1425 error:
1426         btrfs_free_path(path);
1427         return ret;
1428 }
1429
1430 int btrfs_init_new_device(struct btrfs_root *root, char *device_path)
1431 {
1432         struct btrfs_trans_handle *trans;
1433         struct btrfs_device *device;
1434         struct block_device *bdev;
1435         struct list_head *devices;
1436         struct super_block *sb = root->fs_info->sb;
1437         u64 total_bytes;
1438         int seeding_dev = 0;
1439         int ret = 0;
1440
1441         if ((sb->s_flags & MS_RDONLY) && !root->fs_info->fs_devices->seeding)
1442                 return -EINVAL;
1443
1444         bdev = open_bdev_exclusive(device_path, 0, root->fs_info->bdev_holder);
1445         if (IS_ERR(bdev))
1446                 return PTR_ERR(bdev);
1447
1448         if (root->fs_info->fs_devices->seeding) {
1449                 seeding_dev = 1;
1450                 down_write(&sb->s_umount);
1451                 mutex_lock(&uuid_mutex);
1452         }
1453
1454         filemap_write_and_wait(bdev->bd_inode->i_mapping);
1455         mutex_lock(&root->fs_info->volume_mutex);
1456
1457         devices = &root->fs_info->fs_devices->devices;
1458         /*
1459          * we have the volume lock, so we don't need the extra
1460          * device list mutex while reading the list here.
1461          */
1462         list_for_each_entry(device, devices, dev_list) {
1463                 if (device->bdev == bdev) {
1464                         ret = -EEXIST;
1465                         goto error;
1466                 }
1467         }
1468
1469         device = kzalloc(sizeof(*device), GFP_NOFS);
1470         if (!device) {
1471                 /* we can safely leave the fs_devices entry around */
1472                 ret = -ENOMEM;
1473                 goto error;
1474         }
1475
1476         device->name = kstrdup(device_path, GFP_NOFS);
1477         if (!device->name) {
1478                 kfree(device);
1479                 ret = -ENOMEM;
1480                 goto error;
1481         }
1482
1483         ret = find_next_devid(root, &device->devid);
1484         if (ret) {
1485                 kfree(device);
1486                 goto error;
1487         }
1488
1489         trans = btrfs_start_transaction(root, 0);
1490         lock_chunks(root);
1491
1492         device->barriers = 1;
1493         device->writeable = 1;
1494         device->work.func = pending_bios_fn;
1495         generate_random_uuid(device->uuid);
1496         spin_lock_init(&device->io_lock);
1497         device->generation = trans->transid;
1498         device->io_width = root->sectorsize;
1499         device->io_align = root->sectorsize;
1500         device->sector_size = root->sectorsize;
1501         device->total_bytes = i_size_read(bdev->bd_inode);
1502         device->disk_total_bytes = device->total_bytes;
1503         device->dev_root = root->fs_info->dev_root;
1504         device->bdev = bdev;
1505         device->in_fs_metadata = 1;
1506         device->mode = 0;
1507         set_blocksize(device->bdev, 4096);
1508
1509         if (seeding_dev) {
1510                 sb->s_flags &= ~MS_RDONLY;
1511                 ret = btrfs_prepare_sprout(trans, root);
1512                 BUG_ON(ret);
1513         }
1514
1515         device->fs_devices = root->fs_info->fs_devices;
1516
1517         /*
1518          * we don't want write_supers to jump in here with our device
1519          * half setup
1520          */
1521         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
1522         list_add(&device->dev_list, &root->fs_info->fs_devices->devices);
1523         list_add(&device->dev_alloc_list,
1524                  &root->fs_info->fs_devices->alloc_list);
1525         root->fs_info->fs_devices->num_devices++;
1526         root->fs_info->fs_devices->open_devices++;
1527         root->fs_info->fs_devices->rw_devices++;
1528         root->fs_info->fs_devices->total_rw_bytes += device->total_bytes;
1529
1530         if (!blk_queue_nonrot(bdev_get_queue(bdev)))
1531                 root->fs_info->fs_devices->rotating = 1;
1532
1533         total_bytes = btrfs_super_total_bytes(&root->fs_info->super_copy);
1534         btrfs_set_super_total_bytes(&root->fs_info->super_copy,
1535                                     total_bytes + device->total_bytes);
1536
1537         total_bytes = btrfs_super_num_devices(&root->fs_info->super_copy);
1538         btrfs_set_super_num_devices(&root->fs_info->super_copy,
1539                                     total_bytes + 1);
1540         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1541
1542         if (seeding_dev) {
1543                 ret = init_first_rw_device(trans, root, device);
1544                 BUG_ON(ret);
1545                 ret = btrfs_finish_sprout(trans, root);
1546                 BUG_ON(ret);
1547         } else {
1548                 ret = btrfs_add_device(trans, root, device);
1549         }
1550
1551         /*
1552          * we've got more storage, clear any full flags on the space
1553          * infos
1554          */
1555         btrfs_clear_space_info_full(root->fs_info);
1556
1557         unlock_chunks(root);
1558         btrfs_commit_transaction(trans, root);
1559
1560         if (seeding_dev) {
1561                 mutex_unlock(&uuid_mutex);
1562                 up_write(&sb->s_umount);
1563
1564                 ret = btrfs_relocate_sys_chunks(root);
1565                 BUG_ON(ret);
1566         }
1567 out:
1568         mutex_unlock(&root->fs_info->volume_mutex);
1569         return ret;
1570 error:
1571         close_bdev_exclusive(bdev, 0);
1572         if (seeding_dev) {
1573                 mutex_unlock(&uuid_mutex);
1574                 up_write(&sb->s_umount);
1575         }
1576         goto out;
1577 }
1578
1579 static noinline int btrfs_update_device(struct btrfs_trans_handle *trans,
1580                                         struct btrfs_device *device)
1581 {
1582         int ret;
1583         struct btrfs_path *path;
1584         struct btrfs_root *root;
1585         struct btrfs_dev_item *dev_item;
1586         struct extent_buffer *leaf;
1587         struct btrfs_key key;
1588
1589         root = device->dev_root->fs_info->chunk_root;
1590
1591         path = btrfs_alloc_path();
1592         if (!path)
1593                 return -ENOMEM;
1594
1595         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1596         key.type = BTRFS_DEV_ITEM_KEY;
1597         key.offset = device->devid;
1598
1599         ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
1600         if (ret < 0)
1601                 goto out;
1602
1603         if (ret > 0) {
1604                 ret = -ENOENT;
1605                 goto out;
1606         }
1607
1608         leaf = path->nodes[0];
1609         dev_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dev_item);
1610
1611         btrfs_set_device_id(leaf, dev_item, device->devid);
1612         btrfs_set_device_type(leaf, dev_item, device->type);
1613         btrfs_set_device_io_align(leaf, dev_item, device->io_align);
1614         btrfs_set_device_io_width(leaf, dev_item, device->io_width);
1615         btrfs_set_device_sector_size(leaf, dev_item, device->sector_size);
1616         btrfs_set_device_total_bytes(leaf, dev_item, device->disk_total_bytes);
1617         btrfs_set_device_bytes_used(leaf, dev_item, device->bytes_used);
1618         btrfs_mark_buffer_dirty(leaf);
1619
1620 out:
1621         btrfs_free_path(path);
1622         return ret;
1623 }
1624
1625 static int __btrfs_grow_device(struct btrfs_trans_handle *trans,
1626                       struct btrfs_device *device, u64 new_size)
1627 {
1628         struct btrfs_super_block *super_copy =
1629                 &device->dev_root->fs_info->super_copy;
1630         u64 old_total = btrfs_super_total_bytes(super_copy);
1631         u64 diff = new_size - device->total_bytes;
1632
1633         if (!device->writeable)
1634                 return -EACCES;
1635         if (new_size <= device->total_bytes)
1636                 return -EINVAL;
1637
1638         btrfs_set_super_total_bytes(super_copy, old_total + diff);
1639         device->fs_devices->total_rw_bytes += diff;
1640
1641         device->total_bytes = new_size;
1642         device->disk_total_bytes = new_size;
1643         btrfs_clear_space_info_full(device->dev_root->fs_info);
1644
1645         return btrfs_update_device(trans, device);
1646 }
1647
1648 int btrfs_grow_device(struct btrfs_trans_handle *trans,
1649                       struct btrfs_device *device, u64 new_size)
1650 {
1651         int ret;
1652         lock_chunks(device->dev_root);
1653         ret = __btrfs_grow_device(trans, device, new_size);
1654         unlock_chunks(device->dev_root);
1655         return ret;
1656 }
1657
1658 static int btrfs_free_chunk(struct btrfs_trans_handle *trans,
1659                             struct btrfs_root *root,
1660                             u64 chunk_tree, u64 chunk_objectid,
1661                             u64 chunk_offset)
1662 {
1663         int ret;
1664         struct btrfs_path *path;
1665         struct btrfs_key key;
1666
1667         root = root->fs_info->chunk_root;
1668         path = btrfs_alloc_path();
1669         if (!path)
1670                 return -ENOMEM;
1671
1672         key.objectid = chunk_objectid;
1673         key.offset = chunk_offset;
1674         key.type = BTRFS_CHUNK_ITEM_KEY;
1675
1676         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1677         BUG_ON(ret);
1678
1679         ret = btrfs_del_item(trans, root, path);
1680         BUG_ON(ret);
1681
1682         btrfs_free_path(path);
1683         return 0;
1684 }
1685
1686 static int btrfs_del_sys_chunk(struct btrfs_root *root, u64 chunk_objectid, u64
1687                         chunk_offset)
1688 {
1689         struct btrfs_super_block *super_copy = &root->fs_info->super_copy;
1690         struct btrfs_disk_key *disk_key;
1691         struct btrfs_chunk *chunk;
1692         u8 *ptr;
1693         int ret = 0;
1694         u32 num_stripes;
1695         u32 array_size;
1696         u32 len = 0;
1697         u32 cur;
1698         struct btrfs_key key;
1699
1700         array_size = btrfs_super_sys_array_size(super_copy);
1701
1702         ptr = super_copy->sys_chunk_array;
1703         cur = 0;
1704
1705         while (cur < array_size) {
1706                 disk_key = (struct btrfs_disk_key *)ptr;
1707                 btrfs_disk_key_to_cpu(&key, disk_key);
1708
1709                 len = sizeof(*disk_key);
1710
1711                 if (key.type == BTRFS_CHUNK_ITEM_KEY) {
1712                         chunk = (struct btrfs_chunk *)(ptr + len);
1713                         num_stripes = btrfs_stack_chunk_num_stripes(chunk);
1714                         len += btrfs_chunk_item_size(num_stripes);
1715                 } else {
1716                         ret = -EIO;
1717                         break;
1718                 }
1719                 if (key.objectid == chunk_objectid &&
1720                     key.offset == chunk_offset) {
1721                         memmove(ptr, ptr + len, array_size - (cur + len));
1722                         array_size -= len;
1723                         btrfs_set_super_sys_array_size(super_copy, array_size);
1724                 } else {
1725                         ptr += len;
1726                         cur += len;
1727                 }
1728         }
1729         return ret;
1730 }
1731
1732 static int btrfs_relocate_chunk(struct btrfs_root *root,
1733                          u64 chunk_tree, u64 chunk_objectid,
1734                          u64 chunk_offset)
1735 {
1736         struct extent_map_tree *em_tree;
1737         struct btrfs_root *extent_root;
1738         struct btrfs_trans_handle *trans;
1739         struct extent_map *em;
1740         struct map_lookup *map;
1741         int ret;
1742         int i;
1743
1744         root = root->fs_info->chunk_root;
1745         extent_root = root->fs_info->extent_root;
1746         em_tree = &root->fs_info->mapping_tree.map_tree;
1747
1748         ret = btrfs_can_relocate(extent_root, chunk_offset);
1749         if (ret)
1750                 return -ENOSPC;
1751
1752         /* step one, relocate all the extents inside this chunk */
1753         ret = btrfs_relocate_block_group(extent_root, chunk_offset);
1754         if (ret)
1755                 return ret;
1756
1757         trans = btrfs_start_transaction(root, 0);
1758         BUG_ON(!trans);
1759
1760         lock_chunks(root);
1761
1762         /*
1763          * step two, delete the device extents and the
1764          * chunk tree entries
1765          */
1766         read_lock(&em_tree->lock);
1767         em = lookup_extent_mapping(em_tree, chunk_offset, 1);
1768         read_unlock(&em_tree->lock);
1769
1770         BUG_ON(em->start > chunk_offset ||
1771                em->start + em->len < chunk_offset);
1772         map = (struct map_lookup *)em->bdev;
1773
1774         for (i = 0; i < map->num_stripes; i++) {
1775                 ret = btrfs_free_dev_extent(trans, map->stripes[i].dev,
1776                                             map->stripes[i].physical);
1777                 BUG_ON(ret);
1778
1779                 if (map->stripes[i].dev) {
1780                         ret = btrfs_update_device(trans, map->stripes[i].dev);
1781                         BUG_ON(ret);
1782                 }
1783         }
1784         ret = btrfs_free_chunk(trans, root, chunk_tree, chunk_objectid,
1785                                chunk_offset);
1786
1787         BUG_ON(ret);
1788
1789         if (map->type & BTRFS_BLOCK_GROUP_SYSTEM) {
1790                 ret = btrfs_del_sys_chunk(root, chunk_objectid, chunk_offset);
1791                 BUG_ON(ret);
1792         }
1793
1794         ret = btrfs_remove_block_group(trans, extent_root, chunk_offset);
1795         BUG_ON(ret);
1796
1797         write_lock(&em_tree->lock);
1798         remove_extent_mapping(em_tree, em);
1799         write_unlock(&em_tree->lock);
1800
1801         kfree(map);
1802         em->bdev = NULL;
1803
1804         /* once for the tree */
1805         free_extent_map(em);
1806         /* once for us */
1807         free_extent_map(em);
1808
1809         unlock_chunks(root);
1810         btrfs_end_transaction(trans, root);
1811         return 0;
1812 }
1813
1814 static int btrfs_relocate_sys_chunks(struct btrfs_root *root)
1815 {
1816         struct btrfs_root *chunk_root = root->fs_info->chunk_root;
1817         struct btrfs_path *path;
1818         struct extent_buffer *leaf;
1819         struct btrfs_chunk *chunk;
1820         struct btrfs_key key;
1821         struct btrfs_key found_key;
1822         u64 chunk_tree = chunk_root->root_key.objectid;
1823         u64 chunk_type;
1824         bool retried = false;
1825         int failed = 0;
1826         int ret;
1827
1828         path = btrfs_alloc_path();
1829         if (!path)
1830                 return -ENOMEM;
1831
1832 again:
1833         key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
1834         key.offset = (u64)-1;
1835         key.type = BTRFS_CHUNK_ITEM_KEY;
1836
1837         while (1) {
1838                 ret = btrfs_search_slot(NULL, chunk_root, &key, path, 0, 0);
1839                 if (ret < 0)
1840                         goto error;
1841                 BUG_ON(ret == 0);
1842
1843                 ret = btrfs_previous_item(chunk_root, path, key.objectid,
1844                                           key.type);
1845                 if (ret < 0)
1846                         goto error;
1847                 if (ret > 0)
1848                         break;
1849
1850                 leaf = path->nodes[0];
1851                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1852
1853                 chunk = btrfs_item_ptr(leaf, path->slots[0],
1854                                        struct btrfs_chunk);
1855                 chunk_type = btrfs_chunk_type(leaf, chunk);
1856                 btrfs_release_path(chunk_root, path);
1857
1858                 if (chunk_type & BTRFS_BLOCK_GROUP_SYSTEM) {
1859                         ret = btrfs_relocate_chunk(chunk_root, chunk_tree,
1860                                                    found_key.objectid,
1861                                                    found_key.offset);
1862                         if (ret == -ENOSPC)
1863                                 failed++;
1864                         else if (ret)
1865                                 BUG();
1866                 }
1867
1868                 if (found_key.offset == 0)
1869                         break;
1870                 key.offset = found_key.offset - 1;
1871         }
1872         ret = 0;
1873         if (failed && !retried) {
1874                 failed = 0;
1875                 retried = true;
1876                 goto again;
1877         } else if (failed && retried) {
1878                 WARN_ON(1);
1879                 ret = -ENOSPC;
1880         }
1881 error:
1882         btrfs_free_path(path);
1883         return ret;
1884 }
1885
1886 static u64 div_factor(u64 num, int factor)
1887 {
1888         if (factor == 10)
1889                 return num;
1890         num *= factor;
1891         do_div(num, 10);
1892         return num;
1893 }
1894
1895 int btrfs_balance(struct btrfs_root *dev_root)
1896 {
1897         int ret;
1898         struct list_head *devices = &dev_root->fs_info->fs_devices->devices;
1899         struct btrfs_device *device;
1900         u64 old_size;
1901         u64 size_to_free;
1902         struct btrfs_path *path;
1903         struct btrfs_key key;
1904         struct btrfs_chunk *chunk;
1905         struct btrfs_root *chunk_root = dev_root->fs_info->chunk_root;
1906         struct btrfs_trans_handle *trans;
1907         struct btrfs_key found_key;
1908
1909         if (dev_root->fs_info->sb->s_flags & MS_RDONLY)
1910                 return -EROFS;
1911
1912         mutex_lock(&dev_root->fs_info->volume_mutex);
1913         dev_root = dev_root->fs_info->dev_root;
1914
1915         /* step one make some room on all the devices */
1916         list_for_each_entry(device, devices, dev_list) {
1917                 old_size = device->total_bytes;
1918                 size_to_free = div_factor(old_size, 1);
1919                 size_to_free = min(size_to_free, (u64)1 * 1024 * 1024);
1920                 if (!device->writeable ||
1921                     device->total_bytes - device->bytes_used > size_to_free)
1922                         continue;
1923
1924                 ret = btrfs_shrink_device(device, old_size - size_to_free);
1925                 if (ret == -ENOSPC)
1926                         break;
1927                 BUG_ON(ret);
1928
1929                 trans = btrfs_start_transaction(dev_root, 0);
1930                 BUG_ON(!trans);
1931
1932                 ret = btrfs_grow_device(trans, device, old_size);
1933                 BUG_ON(ret);
1934
1935                 btrfs_end_transaction(trans, dev_root);
1936         }
1937
1938         /* step two, relocate all the chunks */
1939         path = btrfs_alloc_path();
1940         BUG_ON(!path);
1941
1942         key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
1943         key.offset = (u64)-1;
1944         key.type = BTRFS_CHUNK_ITEM_KEY;
1945
1946         while (1) {
1947                 ret = btrfs_search_slot(NULL, chunk_root, &key, path, 0, 0);
1948                 if (ret < 0)
1949                         goto error;
1950
1951                 /*
1952                  * this shouldn't happen, it means the last relocate
1953                  * failed
1954                  */
1955                 if (ret == 0)
1956                         break;
1957
1958                 ret = btrfs_previous_item(chunk_root, path, 0,
1959                                           BTRFS_CHUNK_ITEM_KEY);
1960                 if (ret)
1961                         break;
1962
1963                 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
1964                                       path->slots[0]);
1965                 if (found_key.objectid != key.objectid)
1966                         break;
1967
1968                 chunk = btrfs_item_ptr(path->nodes[0],
1969                                        path->slots[0],
1970                                        struct btrfs_chunk);
1971                 /* chunk zero is special */
1972                 if (found_key.offset == 0)
1973                         break;
1974
1975                 btrfs_release_path(chunk_root, path);
1976                 ret = btrfs_relocate_chunk(chunk_root,
1977                                            chunk_root->root_key.objectid,
1978                                            found_key.objectid,
1979                                            found_key.offset);
1980                 BUG_ON(ret && ret != -ENOSPC);
1981                 key.offset = found_key.offset - 1;
1982         }
1983         ret = 0;
1984 error:
1985         btrfs_free_path(path);
1986         mutex_unlock(&dev_root->fs_info->volume_mutex);
1987         return ret;
1988 }
1989
1990 /*
1991  * shrinking a device means finding all of the device extents past
1992  * the new size, and then following the back refs to the chunks.
1993  * The chunk relocation code actually frees the device extent
1994  */
1995 int btrfs_shrink_device(struct btrfs_device *device, u64 new_size)
1996 {
1997         struct btrfs_trans_handle *trans;
1998         struct btrfs_root *root = device->dev_root;
1999         struct btrfs_dev_extent *dev_extent = NULL;
2000         struct btrfs_path *path;
2001         u64 length;
2002         u64 chunk_tree;
2003         u64 chunk_objectid;
2004         u64 chunk_offset;
2005         int ret;
2006         int slot;
2007         int failed = 0;
2008         bool retried = false;
2009         struct extent_buffer *l;
2010         struct btrfs_key key;
2011         struct btrfs_super_block *super_copy = &root->fs_info->super_copy;
2012         u64 old_total = btrfs_super_total_bytes(super_copy);
2013         u64 old_size = device->total_bytes;
2014         u64 diff = device->total_bytes - new_size;
2015
2016         if (new_size >= device->total_bytes)
2017                 return -EINVAL;
2018
2019         path = btrfs_alloc_path();
2020         if (!path)
2021                 return -ENOMEM;
2022
2023         path->reada = 2;
2024
2025         lock_chunks(root);
2026
2027         device->total_bytes = new_size;
2028         if (device->writeable)
2029                 device->fs_devices->total_rw_bytes -= diff;
2030         unlock_chunks(root);
2031
2032 again:
2033         key.objectid = device->devid;
2034         key.offset = (u64)-1;
2035         key.type = BTRFS_DEV_EXTENT_KEY;
2036
2037         while (1) {
2038                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2039                 if (ret < 0)
2040                         goto done;
2041
2042                 ret = btrfs_previous_item(root, path, 0, key.type);
2043                 if (ret < 0)
2044                         goto done;
2045                 if (ret) {
2046                         ret = 0;
2047                         btrfs_release_path(root, path);
2048                         break;
2049                 }
2050
2051                 l = path->nodes[0];
2052                 slot = path->slots[0];
2053                 btrfs_item_key_to_cpu(l, &key, path->slots[0]);
2054
2055                 if (key.objectid != device->devid) {
2056                         btrfs_release_path(root, path);
2057                         break;
2058                 }
2059
2060                 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
2061                 length = btrfs_dev_extent_length(l, dev_extent);
2062
2063                 if (key.offset + length <= new_size) {
2064                         btrfs_release_path(root, path);
2065                         break;
2066                 }
2067
2068                 chunk_tree = btrfs_dev_extent_chunk_tree(l, dev_extent);
2069                 chunk_objectid = btrfs_dev_extent_chunk_objectid(l, dev_extent);
2070                 chunk_offset = btrfs_dev_extent_chunk_offset(l, dev_extent);
2071                 btrfs_release_path(root, path);
2072
2073                 ret = btrfs_relocate_chunk(root, chunk_tree, chunk_objectid,
2074                                            chunk_offset);
2075                 if (ret && ret != -ENOSPC)
2076                         goto done;
2077                 if (ret == -ENOSPC)
2078                         failed++;
2079                 key.offset -= 1;
2080         }
2081
2082         if (failed && !retried) {
2083                 failed = 0;
2084                 retried = true;
2085                 goto again;
2086         } else if (failed && retried) {
2087                 ret = -ENOSPC;
2088                 lock_chunks(root);
2089
2090                 device->total_bytes = old_size;
2091                 if (device->writeable)
2092                         device->fs_devices->total_rw_bytes += diff;
2093                 unlock_chunks(root);
2094                 goto done;
2095         }
2096
2097         /* Shrinking succeeded, else we would be at "done". */
2098         trans = btrfs_start_transaction(root, 0);
2099         lock_chunks(root);
2100
2101         device->disk_total_bytes = new_size;
2102         /* Now btrfs_update_device() will change the on-disk size. */
2103         ret = btrfs_update_device(trans, device);
2104         if (ret) {
2105                 unlock_chunks(root);
2106                 btrfs_end_transaction(trans, root);
2107                 goto done;
2108         }
2109         WARN_ON(diff > old_total);
2110         btrfs_set_super_total_bytes(super_copy, old_total - diff);
2111         unlock_chunks(root);
2112         btrfs_end_transaction(trans, root);
2113 done:
2114         btrfs_free_path(path);
2115         return ret;
2116 }
2117
2118 static int btrfs_add_system_chunk(struct btrfs_trans_handle *trans,
2119                            struct btrfs_root *root,
2120                            struct btrfs_key *key,
2121                            struct btrfs_chunk *chunk, int item_size)
2122 {
2123         struct btrfs_super_block *super_copy = &root->fs_info->super_copy;
2124         struct btrfs_disk_key disk_key;
2125         u32 array_size;
2126         u8 *ptr;
2127
2128         array_size = btrfs_super_sys_array_size(super_copy);
2129         if (array_size + item_size > BTRFS_SYSTEM_CHUNK_ARRAY_SIZE)
2130                 return -EFBIG;
2131
2132         ptr = super_copy->sys_chunk_array + array_size;
2133         btrfs_cpu_key_to_disk(&disk_key, key);
2134         memcpy(ptr, &disk_key, sizeof(disk_key));
2135         ptr += sizeof(disk_key);
2136         memcpy(ptr, chunk, item_size);
2137         item_size += sizeof(disk_key);
2138         btrfs_set_super_sys_array_size(super_copy, array_size + item_size);
2139         return 0;
2140 }
2141
2142 static noinline u64 chunk_bytes_by_type(u64 type, u64 calc_size,
2143                                         int num_stripes, int sub_stripes)
2144 {
2145         if (type & (BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_DUP))
2146                 return calc_size;
2147         else if (type & BTRFS_BLOCK_GROUP_RAID10)
2148                 return calc_size * (num_stripes / sub_stripes);
2149         else
2150                 return calc_size * num_stripes;
2151 }
2152
2153 static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
2154                                struct btrfs_root *extent_root,
2155                                struct map_lookup **map_ret,
2156                                u64 *num_bytes, u64 *stripe_size,
2157                                u64 start, u64 type)
2158 {
2159         struct btrfs_fs_info *info = extent_root->fs_info;
2160         struct btrfs_device *device = NULL;
2161         struct btrfs_fs_devices *fs_devices = info->fs_devices;
2162         struct list_head *cur;
2163         struct map_lookup *map = NULL;
2164         struct extent_map_tree *em_tree;
2165         struct extent_map *em;
2166         struct list_head private_devs;
2167         int min_stripe_size = 1 * 1024 * 1024;
2168         u64 calc_size = 1024 * 1024 * 1024;
2169         u64 max_chunk_size = calc_size;
2170         u64 min_free;
2171         u64 avail;
2172         u64 max_avail = 0;
2173         u64 dev_offset;
2174         int num_stripes = 1;
2175         int min_stripes = 1;
2176         int sub_stripes = 0;
2177         int looped = 0;
2178         int ret;
2179         int index;
2180         int stripe_len = 64 * 1024;
2181
2182         if ((type & BTRFS_BLOCK_GROUP_RAID1) &&
2183             (type & BTRFS_BLOCK_GROUP_DUP)) {
2184                 WARN_ON(1);
2185                 type &= ~BTRFS_BLOCK_GROUP_DUP;
2186         }
2187         if (list_empty(&fs_devices->alloc_list))
2188                 return -ENOSPC;
2189
2190         if (type & (BTRFS_BLOCK_GROUP_RAID0)) {
2191                 num_stripes = fs_devices->rw_devices;
2192                 min_stripes = 2;
2193         }
2194         if (type & (BTRFS_BLOCK_GROUP_DUP)) {
2195                 num_stripes = 2;
2196                 min_stripes = 2;
2197         }
2198         if (type & (BTRFS_BLOCK_GROUP_RAID1)) {
2199                 if (fs_devices->rw_devices < 2)
2200                         return -ENOSPC;
2201                 num_stripes = 2;
2202                 min_stripes = 2;
2203         }
2204         if (type & (BTRFS_BLOCK_GROUP_RAID10)) {
2205                 num_stripes = fs_devices->rw_devices;
2206                 if (num_stripes < 4)
2207                         return -ENOSPC;
2208                 num_stripes &= ~(u32)1;
2209                 sub_stripes = 2;
2210                 min_stripes = 4;
2211         }
2212
2213         if (type & BTRFS_BLOCK_GROUP_DATA) {
2214                 max_chunk_size = 10 * calc_size;
2215                 min_stripe_size = 64 * 1024 * 1024;
2216         } else if (type & BTRFS_BLOCK_GROUP_METADATA) {
2217                 max_chunk_size = 256 * 1024 * 1024;
2218                 min_stripe_size = 32 * 1024 * 1024;
2219         } else if (type & BTRFS_BLOCK_GROUP_SYSTEM) {
2220                 calc_size = 8 * 1024 * 1024;
2221                 max_chunk_size = calc_size * 2;
2222                 min_stripe_size = 1 * 1024 * 1024;
2223         }
2224
2225         /* we don't want a chunk larger than 10% of writeable space */
2226         max_chunk_size = min(div_factor(fs_devices->total_rw_bytes, 1),
2227                              max_chunk_size);
2228
2229 again:
2230         max_avail = 0;
2231         if (!map || map->num_stripes != num_stripes) {
2232                 kfree(map);
2233                 map = kmalloc(map_lookup_size(num_stripes), GFP_NOFS);
2234                 if (!map)
2235                         return -ENOMEM;
2236                 map->num_stripes = num_stripes;
2237         }
2238
2239         if (calc_size * num_stripes > max_chunk_size) {
2240                 calc_size = max_chunk_size;
2241                 do_div(calc_size, num_stripes);
2242                 do_div(calc_size, stripe_len);
2243                 calc_size *= stripe_len;
2244         }
2245
2246         /* we don't want tiny stripes */
2247         if (!looped)
2248                 calc_size = max_t(u64, min_stripe_size, calc_size);
2249
2250         /*
2251          * we're about to do_div by the stripe_len so lets make sure
2252          * we end up with something bigger than a stripe
2253          */
2254         calc_size = max_t(u64, calc_size, stripe_len * 4);
2255
2256         do_div(calc_size, stripe_len);
2257         calc_size *= stripe_len;
2258
2259         cur = fs_devices->alloc_list.next;
2260         index = 0;
2261
2262         if (type & BTRFS_BLOCK_GROUP_DUP)
2263                 min_free = calc_size * 2;
2264         else
2265                 min_free = calc_size;
2266
2267         /*
2268          * we add 1MB because we never use the first 1MB of the device, unless
2269          * we've looped, then we are likely allocating the maximum amount of
2270          * space left already
2271          */
2272         if (!looped)
2273                 min_free += 1024 * 1024;
2274
2275         INIT_LIST_HEAD(&private_devs);
2276         while (index < num_stripes) {
2277                 device = list_entry(cur, struct btrfs_device, dev_alloc_list);
2278                 BUG_ON(!device->writeable);
2279                 if (device->total_bytes > device->bytes_used)
2280                         avail = device->total_bytes - device->bytes_used;
2281                 else
2282                         avail = 0;
2283                 cur = cur->next;
2284
2285                 if (device->in_fs_metadata && avail >= min_free) {
2286                         ret = find_free_dev_extent(trans, device,
2287                                                    min_free, &dev_offset,
2288                                                    &max_avail);
2289                         if (ret == 0) {
2290                                 list_move_tail(&device->dev_alloc_list,
2291                                                &private_devs);
2292                                 map->stripes[index].dev = device;
2293                                 map->stripes[index].physical = dev_offset;
2294                                 index++;
2295                                 if (type & BTRFS_BLOCK_GROUP_DUP) {
2296                                         map->stripes[index].dev = device;
2297                                         map->stripes[index].physical =
2298                                                 dev_offset + calc_size;
2299                                         index++;
2300                                 }
2301                         }
2302                 } else if (device->in_fs_metadata && avail > max_avail)
2303                         max_avail = avail;
2304                 if (cur == &fs_devices->alloc_list)
2305                         break;
2306         }
2307         list_splice(&private_devs, &fs_devices->alloc_list);
2308         if (index < num_stripes) {
2309                 if (index >= min_stripes) {
2310                         num_stripes = index;
2311                         if (type & (BTRFS_BLOCK_GROUP_RAID10)) {
2312                                 num_stripes /= sub_stripes;
2313                                 num_stripes *= sub_stripes;
2314                         }
2315                         looped = 1;
2316                         goto again;
2317                 }
2318                 if (!looped && max_avail > 0) {
2319                         looped = 1;
2320                         calc_size = max_avail;
2321                         goto again;
2322                 }
2323                 kfree(map);
2324                 return -ENOSPC;
2325         }
2326         map->sector_size = extent_root->sectorsize;
2327         map->stripe_len = stripe_len;
2328         map->io_align = stripe_len;
2329         map->io_width = stripe_len;
2330         map->type = type;
2331         map->num_stripes = num_stripes;
2332         map->sub_stripes = sub_stripes;
2333
2334         *map_ret = map;
2335         *stripe_size = calc_size;
2336         *num_bytes = chunk_bytes_by_type(type, calc_size,
2337                                          num_stripes, sub_stripes);
2338
2339         em = alloc_extent_map(GFP_NOFS);
2340         if (!em) {
2341                 kfree(map);
2342                 return -ENOMEM;
2343         }
2344         em->bdev = (struct block_device *)map;
2345         em->start = start;
2346         em->len = *num_bytes;
2347         em->block_start = 0;
2348         em->block_len = em->len;
2349
2350         em_tree = &extent_root->fs_info->mapping_tree.map_tree;
2351         write_lock(&em_tree->lock);
2352         ret = add_extent_mapping(em_tree, em);
2353         write_unlock(&em_tree->lock);
2354         BUG_ON(ret);
2355         free_extent_map(em);
2356
2357         ret = btrfs_make_block_group(trans, extent_root, 0, type,
2358                                      BTRFS_FIRST_CHUNK_TREE_OBJECTID,
2359                                      start, *num_bytes);
2360         BUG_ON(ret);
2361
2362         index = 0;
2363         while (index < map->num_stripes) {
2364                 device = map->stripes[index].dev;
2365                 dev_offset = map->stripes[index].physical;
2366
2367                 ret = btrfs_alloc_dev_extent(trans, device,
2368                                 info->chunk_root->root_key.objectid,
2369                                 BTRFS_FIRST_CHUNK_TREE_OBJECTID,
2370                                 start, dev_offset, calc_size);
2371                 BUG_ON(ret);
2372                 index++;
2373         }
2374
2375         return 0;
2376 }
2377
2378 static int __finish_chunk_alloc(struct btrfs_trans_handle *trans,
2379                                 struct btrfs_root *extent_root,
2380                                 struct map_lookup *map, u64 chunk_offset,
2381                                 u64 chunk_size, u64 stripe_size)
2382 {
2383         u64 dev_offset;
2384         struct btrfs_key key;
2385         struct btrfs_root *chunk_root = extent_root->fs_info->chunk_root;
2386         struct btrfs_device *device;
2387         struct btrfs_chunk *chunk;
2388         struct btrfs_stripe *stripe;
2389         size_t item_size = btrfs_chunk_item_size(map->num_stripes);
2390         int index = 0;
2391         int ret;
2392
2393         chunk = kzalloc(item_size, GFP_NOFS);
2394         if (!chunk)
2395                 return -ENOMEM;
2396
2397         index = 0;
2398         while (index < map->num_stripes) {
2399                 device = map->stripes[index].dev;
2400                 device->bytes_used += stripe_size;
2401                 ret = btrfs_update_device(trans, device);
2402                 BUG_ON(ret);
2403                 index++;
2404         }
2405
2406         index = 0;
2407         stripe = &chunk->stripe;
2408         while (index < map->num_stripes) {
2409                 device = map->stripes[index].dev;
2410                 dev_offset = map->stripes[index].physical;
2411
2412                 btrfs_set_stack_stripe_devid(stripe, device->devid);
2413                 btrfs_set_stack_stripe_offset(stripe, dev_offset);
2414                 memcpy(stripe->dev_uuid, device->uuid, BTRFS_UUID_SIZE);
2415                 stripe++;
2416                 index++;
2417         }
2418
2419         btrfs_set_stack_chunk_length(chunk, chunk_size);
2420         btrfs_set_stack_chunk_owner(chunk, extent_root->root_key.objectid);
2421         btrfs_set_stack_chunk_stripe_len(chunk, map->stripe_len);
2422         btrfs_set_stack_chunk_type(chunk, map->type);
2423         btrfs_set_stack_chunk_num_stripes(chunk, map->num_stripes);
2424         btrfs_set_stack_chunk_io_align(chunk, map->stripe_len);
2425         btrfs_set_stack_chunk_io_width(chunk, map->stripe_len);
2426         btrfs_set_stack_chunk_sector_size(chunk, extent_root->sectorsize);
2427         btrfs_set_stack_chunk_sub_stripes(chunk, map->sub_stripes);
2428
2429         key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
2430         key.type = BTRFS_CHUNK_ITEM_KEY;
2431         key.offset = chunk_offset;
2432
2433         ret = btrfs_insert_item(trans, chunk_root, &key, chunk, item_size);
2434         BUG_ON(ret);
2435
2436         if (map->type & BTRFS_BLOCK_GROUP_SYSTEM) {
2437                 ret = btrfs_add_system_chunk(trans, chunk_root, &key, chunk,
2438                                              item_size);
2439                 BUG_ON(ret);
2440         }
2441         kfree(chunk);
2442         return 0;
2443 }
2444
2445 /*
2446  * Chunk allocation falls into two parts. The first part does works
2447  * that make the new allocated chunk useable, but not do any operation
2448  * that modifies the chunk tree. The second part does the works that
2449  * require modifying the chunk tree. This division is important for the
2450  * bootstrap process of adding storage to a seed btrfs.
2451  */
2452 int btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
2453                       struct btrfs_root *extent_root, u64 type)
2454 {
2455         u64 chunk_offset;
2456         u64 chunk_size;
2457         u64 stripe_size;
2458         struct map_lookup *map;
2459         struct btrfs_root *chunk_root = extent_root->fs_info->chunk_root;
2460         int ret;
2461
2462         ret = find_next_chunk(chunk_root, BTRFS_FIRST_CHUNK_TREE_OBJECTID,
2463                               &chunk_offset);
2464         if (ret)
2465                 return ret;
2466
2467         ret = __btrfs_alloc_chunk(trans, extent_root, &map, &chunk_size,
2468                                   &stripe_size, chunk_offset, type);
2469         if (ret)
2470                 return ret;
2471
2472         ret = __finish_chunk_alloc(trans, extent_root, map, chunk_offset,
2473                                    chunk_size, stripe_size);
2474         BUG_ON(ret);
2475         return 0;
2476 }
2477
2478 static noinline int init_first_rw_device(struct btrfs_trans_handle *trans,
2479                                          struct btrfs_root *root,
2480                                          struct btrfs_device *device)
2481 {
2482         u64 chunk_offset;
2483         u64 sys_chunk_offset;
2484         u64 chunk_size;
2485         u64 sys_chunk_size;
2486         u64 stripe_size;
2487         u64 sys_stripe_size;
2488         u64 alloc_profile;
2489         struct map_lookup *map;
2490         struct map_lookup *sys_map;
2491         struct btrfs_fs_info *fs_info = root->fs_info;
2492         struct btrfs_root *extent_root = fs_info->extent_root;
2493         int ret;
2494
2495         ret = find_next_chunk(fs_info->chunk_root,
2496                               BTRFS_FIRST_CHUNK_TREE_OBJECTID, &chunk_offset);
2497         BUG_ON(ret);
2498
2499         alloc_profile = BTRFS_BLOCK_GROUP_METADATA |
2500                         (fs_info->metadata_alloc_profile &
2501                          fs_info->avail_metadata_alloc_bits);
2502         alloc_profile = btrfs_reduce_alloc_profile(root, alloc_profile);
2503
2504         ret = __btrfs_alloc_chunk(trans, extent_root, &map, &chunk_size,
2505                                   &stripe_size, chunk_offset, alloc_profile);
2506         BUG_ON(ret);
2507
2508         sys_chunk_offset = chunk_offset + chunk_size;
2509
2510         alloc_profile = BTRFS_BLOCK_GROUP_SYSTEM |
2511                         (fs_info->system_alloc_profile &
2512                          fs_info->avail_system_alloc_bits);
2513         alloc_profile = btrfs_reduce_alloc_profile(root, alloc_profile);
2514
2515         ret = __btrfs_alloc_chunk(trans, extent_root, &sys_map,
2516                                   &sys_chunk_size, &sys_stripe_size,
2517                                   sys_chunk_offset, alloc_profile);
2518         BUG_ON(ret);
2519
2520         ret = btrfs_add_device(trans, fs_info->chunk_root, device);
2521         BUG_ON(ret);
2522
2523         /*
2524          * Modifying chunk tree needs allocating new blocks from both
2525          * system block group and metadata block group. So we only can
2526          * do operations require modifying the chunk tree after both
2527          * block groups were created.
2528          */
2529         ret = __finish_chunk_alloc(trans, extent_root, map, chunk_offset,
2530                                    chunk_size, stripe_size);
2531         BUG_ON(ret);
2532
2533         ret = __finish_chunk_alloc(trans, extent_root, sys_map,
2534                                    sys_chunk_offset, sys_chunk_size,
2535                                    sys_stripe_size);
2536         BUG_ON(ret);
2537         return 0;
2538 }
2539
2540 int btrfs_chunk_readonly(struct btrfs_root *root, u64 chunk_offset)
2541 {
2542         struct extent_map *em;
2543         struct map_lookup *map;
2544         struct btrfs_mapping_tree *map_tree = &root->fs_info->mapping_tree;
2545         int readonly = 0;
2546         int i;
2547
2548         read_lock(&map_tree->map_tree.lock);
2549         em = lookup_extent_mapping(&map_tree->map_tree, chunk_offset, 1);
2550         read_unlock(&map_tree->map_tree.lock);
2551         if (!em)
2552                 return 1;
2553
2554         if (btrfs_test_opt(root, DEGRADED)) {
2555                 free_extent_map(em);
2556                 return 0;
2557         }
2558
2559         map = (struct map_lookup *)em->bdev;
2560         for (i = 0; i < map->num_stripes; i++) {
2561                 if (!map->stripes[i].dev->writeable) {
2562                         readonly = 1;
2563                         break;
2564                 }
2565         }
2566         free_extent_map(em);
2567         return readonly;
2568 }
2569
2570 void btrfs_mapping_init(struct btrfs_mapping_tree *tree)
2571 {
2572         extent_map_tree_init(&tree->map_tree, GFP_NOFS);
2573 }
2574
2575 void btrfs_mapping_tree_free(struct btrfs_mapping_tree *tree)
2576 {
2577         struct extent_map *em;
2578
2579         while (1) {
2580                 write_lock(&tree->map_tree.lock);
2581                 em = lookup_extent_mapping(&tree->map_tree, 0, (u64)-1);
2582                 if (em)
2583                         remove_extent_mapping(&tree->map_tree, em);
2584                 write_unlock(&tree->map_tree.lock);
2585                 if (!em)
2586                         break;
2587                 kfree(em->bdev);
2588                 /* once for us */
2589                 free_extent_map(em);
2590                 /* once for the tree */
2591                 free_extent_map(em);
2592         }
2593 }
2594
2595 int btrfs_num_copies(struct btrfs_mapping_tree *map_tree, u64 logical, u64 len)
2596 {
2597         struct extent_map *em;
2598         struct map_lookup *map;
2599         struct extent_map_tree *em_tree = &map_tree->map_tree;
2600         int ret;
2601
2602         read_lock(&em_tree->lock);
2603         em = lookup_extent_mapping(em_tree, logical, len);
2604         read_unlock(&em_tree->lock);
2605         BUG_ON(!em);
2606
2607         BUG_ON(em->start > logical || em->start + em->len < logical);
2608         map = (struct map_lookup *)em->bdev;
2609         if (map->type & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1))
2610                 ret = map->num_stripes;
2611         else if (map->type & BTRFS_BLOCK_GROUP_RAID10)
2612                 ret = map->sub_stripes;
2613         else
2614                 ret = 1;
2615         free_extent_map(em);
2616         return ret;
2617 }
2618
2619 static int find_live_mirror(struct map_lookup *map, int first, int num,
2620                             int optimal)
2621 {
2622         int i;
2623         if (map->stripes[optimal].dev->bdev)
2624                 return optimal;
2625         for (i = first; i < first + num; i++) {
2626                 if (map->stripes[i].dev->bdev)
2627                         return i;
2628         }
2629         /* we couldn't find one that doesn't fail.  Just return something
2630          * and the io error handling code will clean up eventually
2631          */
2632         return optimal;
2633 }
2634
2635 static int __btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw,
2636                              u64 logical, u64 *length,
2637                              struct btrfs_multi_bio **multi_ret,
2638                              int mirror_num, struct page *unplug_page)
2639 {
2640         struct extent_map *em;
2641         struct map_lookup *map;
2642         struct extent_map_tree *em_tree = &map_tree->map_tree;
2643         u64 offset;
2644         u64 stripe_offset;
2645         u64 stripe_nr;
2646         int stripes_allocated = 8;
2647         int stripes_required = 1;
2648         int stripe_index;
2649         int i;
2650         int num_stripes;
2651         int max_errors = 0;
2652         struct btrfs_multi_bio *multi = NULL;
2653
2654         if (multi_ret && !(rw & (1 << BIO_RW)))
2655                 stripes_allocated = 1;
2656 again:
2657         if (multi_ret) {
2658                 multi = kzalloc(btrfs_multi_bio_size(stripes_allocated),
2659                                 GFP_NOFS);
2660                 if (!multi)
2661                         return -ENOMEM;
2662
2663                 atomic_set(&multi->error, 0);
2664         }
2665
2666         read_lock(&em_tree->lock);
2667         em = lookup_extent_mapping(em_tree, logical, *length);
2668         read_unlock(&em_tree->lock);
2669
2670         if (!em && unplug_page) {
2671                 kfree(multi);
2672                 return 0;
2673         }
2674
2675         if (!em) {
2676                 printk(KERN_CRIT "unable to find logical %llu len %llu\n",
2677                        (unsigned long long)logical,
2678                        (unsigned long long)*length);
2679                 BUG();
2680         }
2681
2682         BUG_ON(em->start > logical || em->start + em->len < logical);
2683         map = (struct map_lookup *)em->bdev;
2684         offset = logical - em->start;
2685
2686         if (mirror_num > map->num_stripes)
2687                 mirror_num = 0;
2688
2689         /* if our multi bio struct is too small, back off and try again */
2690         if (rw & (1 << BIO_RW)) {
2691                 if (map->type & (BTRFS_BLOCK_GROUP_RAID1 |
2692                                  BTRFS_BLOCK_GROUP_DUP)) {
2693                         stripes_required = map->num_stripes;
2694                         max_errors = 1;
2695                 } else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
2696                         stripes_required = map->sub_stripes;
2697                         max_errors = 1;
2698                 }
2699         }
2700         if (multi_ret && (rw & (1 << BIO_RW)) &&
2701             stripes_allocated < stripes_required) {
2702                 stripes_allocated = map->num_stripes;
2703                 free_extent_map(em);
2704                 kfree(multi);
2705                 goto again;
2706         }
2707         stripe_nr = offset;
2708         /*
2709          * stripe_nr counts the total number of stripes we have to stride
2710          * to get to this block
2711          */
2712         do_div(stripe_nr, map->stripe_len);
2713
2714         stripe_offset = stripe_nr * map->stripe_len;
2715         BUG_ON(offset < stripe_offset);
2716
2717         /* stripe_offset is the offset of this block in its stripe*/
2718         stripe_offset = offset - stripe_offset;
2719
2720         if (map->type & (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID1 |
2721                          BTRFS_BLOCK_GROUP_RAID10 |
2722                          BTRFS_BLOCK_GROUP_DUP)) {
2723                 /* we limit the length of each bio to what fits in a stripe */
2724                 *length = min_t(u64, em->len - offset,
2725                               map->stripe_len - stripe_offset);
2726         } else {
2727                 *length = em->len - offset;
2728         }
2729
2730         if (!multi_ret && !unplug_page)
2731                 goto out;
2732
2733         num_stripes = 1;
2734         stripe_index = 0;
2735         if (map->type & BTRFS_BLOCK_GROUP_RAID1) {
2736                 if (unplug_page || (rw & (1 << BIO_RW)))
2737                         num_stripes = map->num_stripes;
2738                 else if (mirror_num)
2739                         stripe_index = mirror_num - 1;
2740                 else {
2741                         stripe_index = find_live_mirror(map, 0,
2742                                             map->num_stripes,
2743                                             current->pid % map->num_stripes);
2744                 }
2745
2746         } else if (map->type & BTRFS_BLOCK_GROUP_DUP) {
2747                 if (rw & (1 << BIO_RW))
2748                         num_stripes = map->num_stripes;
2749                 else if (mirror_num)
2750                         stripe_index = mirror_num - 1;
2751
2752         } else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
2753                 int factor = map->num_stripes / map->sub_stripes;
2754
2755                 stripe_index = do_div(stripe_nr, factor);
2756                 stripe_index *= map->sub_stripes;
2757
2758                 if (unplug_page || (rw & (1 << BIO_RW)))
2759                         num_stripes = map->sub_stripes;
2760                 else if (mirror_num)
2761                         stripe_index += mirror_num - 1;
2762                 else {
2763                         stripe_index = find_live_mirror(map, stripe_index,
2764                                               map->sub_stripes, stripe_index +
2765                                               current->pid % map->sub_stripes);
2766                 }
2767         } else {
2768                 /*
2769                  * after this do_div call, stripe_nr is the number of stripes
2770                  * on this device we have to walk to find the data, and
2771                  * stripe_index is the number of our device in the stripe array
2772                  */
2773                 stripe_index = do_div(stripe_nr, map->num_stripes);
2774         }
2775         BUG_ON(stripe_index >= map->num_stripes);
2776
2777         for (i = 0; i < num_stripes; i++) {
2778                 if (unplug_page) {
2779                         struct btrfs_device *device;
2780                         struct backing_dev_info *bdi;
2781
2782                         device = map->stripes[stripe_index].dev;
2783                         if (device->bdev) {
2784                                 bdi = blk_get_backing_dev_info(device->bdev);
2785                                 if (bdi->unplug_io_fn)
2786                                         bdi->unplug_io_fn(bdi, unplug_page);
2787                         }
2788                 } else {
2789                         multi->stripes[i].physical =
2790                                 map->stripes[stripe_index].physical +
2791                                 stripe_offset + stripe_nr * map->stripe_len;
2792                         multi->stripes[i].dev = map->stripes[stripe_index].dev;
2793                 }
2794                 stripe_index++;
2795         }
2796         if (multi_ret) {
2797                 *multi_ret = multi;
2798                 multi->num_stripes = num_stripes;
2799                 multi->max_errors = max_errors;
2800         }
2801 out:
2802         free_extent_map(em);
2803         return 0;
2804 }
2805
2806 int btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw,
2807                       u64 logical, u64 *length,
2808                       struct btrfs_multi_bio **multi_ret, int mirror_num)
2809 {
2810         return __btrfs_map_block(map_tree, rw, logical, length, multi_ret,
2811                                  mirror_num, NULL);
2812 }
2813
2814 int btrfs_rmap_block(struct btrfs_mapping_tree *map_tree,
2815                      u64 chunk_start, u64 physical, u64 devid,
2816                      u64 **logical, int *naddrs, int *stripe_len)
2817 {
2818         struct extent_map_tree *em_tree = &map_tree->map_tree;
2819         struct extent_map *em;
2820         struct map_lookup *map;
2821         u64 *buf;
2822         u64 bytenr;
2823         u64 length;
2824         u64 stripe_nr;
2825         int i, j, nr = 0;
2826
2827         read_lock(&em_tree->lock);
2828         em = lookup_extent_mapping(em_tree, chunk_start, 1);
2829         read_unlock(&em_tree->lock);
2830
2831         BUG_ON(!em || em->start != chunk_start);
2832         map = (struct map_lookup *)em->bdev;
2833
2834         length = em->len;
2835         if (map->type & BTRFS_BLOCK_GROUP_RAID10)
2836                 do_div(length, map->num_stripes / map->sub_stripes);
2837         else if (map->type & BTRFS_BLOCK_GROUP_RAID0)
2838                 do_div(length, map->num_stripes);
2839
2840         buf = kzalloc(sizeof(u64) * map->num_stripes, GFP_NOFS);
2841         BUG_ON(!buf);
2842
2843         for (i = 0; i < map->num_stripes; i++) {
2844                 if (devid && map->stripes[i].dev->devid != devid)
2845                         continue;
2846                 if (map->stripes[i].physical > physical ||
2847                     map->stripes[i].physical + length <= physical)
2848                         continue;
2849
2850                 stripe_nr = physical - map->stripes[i].physical;
2851                 do_div(stripe_nr, map->stripe_len);
2852
2853                 if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
2854                         stripe_nr = stripe_nr * map->num_stripes + i;
2855                         do_div(stripe_nr, map->sub_stripes);
2856                 } else if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
2857                         stripe_nr = stripe_nr * map->num_stripes + i;
2858                 }
2859                 bytenr = chunk_start + stripe_nr * map->stripe_len;
2860                 WARN_ON(nr >= map->num_stripes);
2861                 for (j = 0; j < nr; j++) {
2862                         if (buf[j] == bytenr)
2863                                 break;
2864                 }
2865                 if (j == nr) {
2866                         WARN_ON(nr >= map->num_stripes);
2867                         buf[nr++] = bytenr;
2868                 }
2869         }
2870
2871         *logical = buf;
2872         *naddrs = nr;
2873         *stripe_len = map->stripe_len;
2874
2875         free_extent_map(em);
2876         return 0;
2877 }
2878
2879 int btrfs_unplug_page(struct btrfs_mapping_tree *map_tree,
2880                       u64 logical, struct page *page)
2881 {
2882         u64 length = PAGE_CACHE_SIZE;
2883         return __btrfs_map_block(map_tree, READ, logical, &length,
2884                                  NULL, 0, page);
2885 }
2886
2887 static void end_bio_multi_stripe(struct bio *bio, int err)
2888 {
2889         struct btrfs_multi_bio *multi = bio->bi_private;
2890         int is_orig_bio = 0;
2891
2892         if (err)
2893                 atomic_inc(&multi->error);
2894
2895         if (bio == multi->orig_bio)
2896                 is_orig_bio = 1;
2897
2898         if (atomic_dec_and_test(&multi->stripes_pending)) {
2899                 if (!is_orig_bio) {
2900                         bio_put(bio);
2901                         bio = multi->orig_bio;
2902                 }
2903                 bio->bi_private = multi->private;
2904                 bio->bi_end_io = multi->end_io;
2905                 /* only send an error to the higher layers if it is
2906                  * beyond the tolerance of the multi-bio
2907                  */
2908                 if (atomic_read(&multi->error) > multi->max_errors) {
2909                         err = -EIO;
2910                 } else if (err) {
2911                         /*
2912                          * this bio is actually up to date, we didn't
2913                          * go over the max number of errors
2914                          */
2915                         set_bit(BIO_UPTODATE, &bio->bi_flags);
2916                         err = 0;
2917                 }
2918                 kfree(multi);
2919
2920                 bio_endio(bio, err);
2921         } else if (!is_orig_bio) {
2922                 bio_put(bio);
2923         }
2924 }
2925
2926 struct async_sched {
2927         struct bio *bio;
2928         int rw;
2929         struct btrfs_fs_info *info;
2930         struct btrfs_work work;
2931 };
2932
2933 /*
2934  * see run_scheduled_bios for a description of why bios are collected for
2935  * async submit.
2936  *
2937  * This will add one bio to the pending list for a device and make sure
2938  * the work struct is scheduled.
2939  */
2940 static noinline int schedule_bio(struct btrfs_root *root,
2941                                  struct btrfs_device *device,
2942                                  int rw, struct bio *bio)
2943 {
2944         int should_queue = 1;
2945         struct btrfs_pending_bios *pending_bios;
2946
2947         /* don't bother with additional async steps for reads, right now */
2948         if (!(rw & (1 << BIO_RW))) {
2949                 bio_get(bio);
2950                 submit_bio(rw, bio);
2951                 bio_put(bio);
2952                 return 0;
2953         }
2954
2955         /*
2956          * nr_async_bios allows us to reliably return congestion to the
2957          * higher layers.  Otherwise, the async bio makes it appear we have
2958          * made progress against dirty pages when we've really just put it
2959          * on a queue for later
2960          */
2961         atomic_inc(&root->fs_info->nr_async_bios);
2962         WARN_ON(bio->bi_next);
2963         bio->bi_next = NULL;
2964         bio->bi_rw |= rw;
2965
2966         spin_lock(&device->io_lock);
2967         if (bio_rw_flagged(bio, BIO_RW_SYNCIO))
2968                 pending_bios = &device->pending_sync_bios;
2969         else
2970                 pending_bios = &device->pending_bios;
2971
2972         if (pending_bios->tail)
2973                 pending_bios->tail->bi_next = bio;
2974
2975         pending_bios->tail = bio;
2976         if (!pending_bios->head)
2977                 pending_bios->head = bio;
2978         if (device->running_pending)
2979                 should_queue = 0;
2980
2981         spin_unlock(&device->io_lock);
2982
2983         if (should_queue)
2984                 btrfs_queue_worker(&root->fs_info->submit_workers,
2985                                    &device->work);
2986         return 0;
2987 }
2988
2989 int btrfs_map_bio(struct btrfs_root *root, int rw, struct bio *bio,
2990                   int mirror_num, int async_submit)
2991 {
2992         struct btrfs_mapping_tree *map_tree;
2993         struct btrfs_device *dev;
2994         struct bio *first_bio = bio;
2995         u64 logical = (u64)bio->bi_sector << 9;
2996         u64 length = 0;
2997         u64 map_length;
2998         struct btrfs_multi_bio *multi = NULL;
2999         int ret;
3000         int dev_nr = 0;
3001         int total_devs = 1;
3002
3003         length = bio->bi_size;
3004         map_tree = &root->fs_info->mapping_tree;
3005         map_length = length;
3006
3007         ret = btrfs_map_block(map_tree, rw, logical, &map_length, &multi,
3008                               mirror_num);
3009         BUG_ON(ret);
3010
3011         total_devs = multi->num_stripes;
3012         if (map_length < length) {
3013                 printk(KERN_CRIT "mapping failed logical %llu bio len %llu "
3014                        "len %llu\n", (unsigned long long)logical,
3015                        (unsigned long long)length,
3016                        (unsigned long long)map_length);
3017                 BUG();
3018         }
3019         multi->end_io = first_bio->bi_end_io;
3020         multi->private = first_bio->bi_private;
3021         multi->orig_bio = first_bio;
3022         atomic_set(&multi->stripes_pending, multi->num_stripes);
3023
3024         while (dev_nr < total_devs) {
3025                 if (total_devs > 1) {
3026                         if (dev_nr < total_devs - 1) {
3027                                 bio = bio_clone(first_bio, GFP_NOFS);
3028                                 BUG_ON(!bio);
3029                         } else {
3030                                 bio = first_bio;
3031                         }
3032                         bio->bi_private = multi;
3033                         bio->bi_end_io = end_bio_multi_stripe;
3034                 }
3035                 bio->bi_sector = multi->stripes[dev_nr].physical >> 9;
3036                 dev = multi->stripes[dev_nr].dev;
3037                 BUG_ON(rw == WRITE && !dev->writeable);
3038                 if (dev && dev->bdev) {
3039                         bio->bi_bdev = dev->bdev;
3040                         if (async_submit)
3041                                 schedule_bio(root, dev, rw, bio);
3042                         else
3043                                 submit_bio(rw, bio);
3044                 } else {
3045                         bio->bi_bdev = root->fs_info->fs_devices->latest_bdev;
3046                         bio->bi_sector = logical >> 9;
3047                         bio_endio(bio, -EIO);
3048                 }
3049                 dev_nr++;
3050         }
3051         if (total_devs == 1)
3052                 kfree(multi);
3053         return 0;
3054 }
3055
3056 struct btrfs_device *btrfs_find_device(struct btrfs_root *root, u64 devid,
3057                                        u8 *uuid, u8 *fsid)
3058 {
3059         struct btrfs_device *device;
3060         struct btrfs_fs_devices *cur_devices;
3061
3062         cur_devices = root->fs_info->fs_devices;
3063         while (cur_devices) {
3064                 if (!fsid ||
3065                     !memcmp(cur_devices->fsid, fsid, BTRFS_UUID_SIZE)) {
3066                         device = __find_device(&cur_devices->devices,
3067                                                devid, uuid);
3068                         if (device)
3069                                 return device;
3070                 }
3071                 cur_devices = cur_devices->seed;
3072         }
3073         return NULL;
3074 }
3075
3076 static struct btrfs_device *add_missing_dev(struct btrfs_root *root,
3077                                             u64 devid, u8 *dev_uuid)
3078 {
3079         struct btrfs_device *device;
3080         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
3081
3082         device = kzalloc(sizeof(*device), GFP_NOFS);
3083         if (!device)
3084                 return NULL;
3085         list_add(&device->dev_list,
3086                  &fs_devices->devices);
3087         device->barriers = 1;
3088         device->dev_root = root->fs_info->dev_root;
3089         device->devid = devid;
3090         device->work.func = pending_bios_fn;
3091         device->fs_devices = fs_devices;
3092         fs_devices->num_devices++;
3093         spin_lock_init(&device->io_lock);
3094         INIT_LIST_HEAD(&device->dev_alloc_list);
3095         memcpy(device->uuid, dev_uuid, BTRFS_UUID_SIZE);
3096         return device;
3097 }
3098
3099 static int read_one_chunk(struct btrfs_root *root, struct btrfs_key *key,
3100                           struct extent_buffer *leaf,
3101                           struct btrfs_chunk *chunk)
3102 {
3103         struct btrfs_mapping_tree *map_tree = &root->fs_info->mapping_tree;
3104         struct map_lookup *map;
3105         struct extent_map *em;
3106         u64 logical;
3107         u64 length;
3108         u64 devid;
3109         u8 uuid[BTRFS_UUID_SIZE];
3110         int num_stripes;
3111         int ret;
3112         int i;
3113
3114         logical = key->offset;
3115         length = btrfs_chunk_length(leaf, chunk);
3116
3117         read_lock(&map_tree->map_tree.lock);
3118         em = lookup_extent_mapping(&map_tree->map_tree, logical, 1);
3119         read_unlock(&map_tree->map_tree.lock);
3120
3121         /* already mapped? */
3122         if (em && em->start <= logical && em->start + em->len > logical) {
3123                 free_extent_map(em);
3124                 return 0;
3125         } else if (em) {
3126                 free_extent_map(em);
3127         }
3128
3129         em = alloc_extent_map(GFP_NOFS);
3130         if (!em)
3131                 return -ENOMEM;
3132         num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
3133         map = kmalloc(map_lookup_size(num_stripes), GFP_NOFS);
3134         if (!map) {
3135                 free_extent_map(em);
3136                 return -ENOMEM;
3137         }
3138
3139         em->bdev = (struct block_device *)map;
3140         em->start = logical;
3141         em->len = length;
3142         em->block_start = 0;
3143         em->block_len = em->len;
3144
3145         map->num_stripes = num_stripes;
3146         map->io_width = btrfs_chunk_io_width(leaf, chunk);
3147         map->io_align = btrfs_chunk_io_align(leaf, chunk);
3148         map->sector_size = btrfs_chunk_sector_size(leaf, chunk);
3149         map->stripe_len = btrfs_chunk_stripe_len(leaf, chunk);
3150         map->type = btrfs_chunk_type(leaf, chunk);
3151         map->sub_stripes = btrfs_chunk_sub_stripes(leaf, chunk);
3152         for (i = 0; i < num_stripes; i++) {
3153                 map->stripes[i].physical =
3154                         btrfs_stripe_offset_nr(leaf, chunk, i);
3155                 devid = btrfs_stripe_devid_nr(leaf, chunk, i);
3156                 read_extent_buffer(leaf, uuid, (unsigned long)
3157                                    btrfs_stripe_dev_uuid_nr(chunk, i),
3158                                    BTRFS_UUID_SIZE);
3159                 map->stripes[i].dev = btrfs_find_device(root, devid, uuid,
3160                                                         NULL);
3161                 if (!map->stripes[i].dev && !btrfs_test_opt(root, DEGRADED)) {
3162                         kfree(map);
3163                         free_extent_map(em);
3164                         return -EIO;
3165                 }
3166                 if (!map->stripes[i].dev) {
3167                         map->stripes[i].dev =
3168                                 add_missing_dev(root, devid, uuid);
3169                         if (!map->stripes[i].dev) {
3170                                 kfree(map);
3171                                 free_extent_map(em);
3172                                 return -EIO;
3173                         }
3174                 }
3175                 map->stripes[i].dev->in_fs_metadata = 1;
3176         }
3177
3178         write_lock(&map_tree->map_tree.lock);
3179         ret = add_extent_mapping(&map_tree->map_tree, em);
3180         write_unlock(&map_tree->map_tree.lock);
3181         BUG_ON(ret);
3182         free_extent_map(em);
3183
3184         return 0;
3185 }
3186
3187 static int fill_device_from_item(struct extent_buffer *leaf,
3188                                  struct btrfs_dev_item *dev_item,
3189                                  struct btrfs_device *device)
3190 {
3191         unsigned long ptr;
3192
3193         device->devid = btrfs_device_id(leaf, dev_item);
3194         device->disk_total_bytes = btrfs_device_total_bytes(leaf, dev_item);
3195         device->total_bytes = device->disk_total_bytes;
3196         device->bytes_used = btrfs_device_bytes_used(leaf, dev_item);
3197         device->type = btrfs_device_type(leaf, dev_item);
3198         device->io_align = btrfs_device_io_align(leaf, dev_item);
3199         device->io_width = btrfs_device_io_width(leaf, dev_item);
3200         device->sector_size = btrfs_device_sector_size(leaf, dev_item);
3201
3202         ptr = (unsigned long)btrfs_device_uuid(dev_item);
3203         read_extent_buffer(leaf, device->uuid, ptr, BTRFS_UUID_SIZE);
3204
3205         return 0;
3206 }
3207
3208 static int open_seed_devices(struct btrfs_root *root, u8 *fsid)
3209 {
3210         struct btrfs_fs_devices *fs_devices;
3211         int ret;
3212
3213         mutex_lock(&uuid_mutex);
3214
3215         fs_devices = root->fs_info->fs_devices->seed;
3216         while (fs_devices) {
3217                 if (!memcmp(fs_devices->fsid, fsid, BTRFS_UUID_SIZE)) {
3218                         ret = 0;
3219                         goto out;
3220                 }
3221                 fs_devices = fs_devices->seed;
3222         }
3223
3224         fs_devices = find_fsid(fsid);
3225         if (!fs_devices) {
3226                 ret = -ENOENT;
3227                 goto out;
3228         }
3229
3230         fs_devices = clone_fs_devices(fs_devices);
3231         if (IS_ERR(fs_devices)) {
3232                 ret = PTR_ERR(fs_devices);
3233                 goto out;
3234         }
3235
3236         ret = __btrfs_open_devices(fs_devices, FMODE_READ,
3237                                    root->fs_info->bdev_holder);
3238         if (ret)
3239                 goto out;
3240
3241         if (!fs_devices->seeding) {
3242                 __btrfs_close_devices(fs_devices);
3243                 free_fs_devices(fs_devices);
3244                 ret = -EINVAL;
3245                 goto out;
3246         }
3247
3248         fs_devices->seed = root->fs_info->fs_devices->seed;
3249         root->fs_info->fs_devices->seed = fs_devices;
3250 out:
3251         mutex_unlock(&uuid_mutex);
3252         return ret;
3253 }
3254
3255 static int read_one_dev(struct btrfs_root *root,
3256                         struct extent_buffer *leaf,
3257                         struct btrfs_dev_item *dev_item)
3258 {
3259         struct btrfs_device *device;
3260         u64 devid;
3261         int ret;
3262         u8 fs_uuid[BTRFS_UUID_SIZE];
3263         u8 dev_uuid[BTRFS_UUID_SIZE];
3264
3265         devid = btrfs_device_id(leaf, dev_item);
3266         read_extent_buffer(leaf, dev_uuid,
3267                            (unsigned long)btrfs_device_uuid(dev_item),
3268                            BTRFS_UUID_SIZE);
3269         read_extent_buffer(leaf, fs_uuid,
3270                            (unsigned long)btrfs_device_fsid(dev_item),
3271                            BTRFS_UUID_SIZE);
3272
3273         if (memcmp(fs_uuid, root->fs_info->fsid, BTRFS_UUID_SIZE)) {
3274                 ret = open_seed_devices(root, fs_uuid);
3275                 if (ret && !btrfs_test_opt(root, DEGRADED))
3276                         return ret;
3277         }
3278
3279         device = btrfs_find_device(root, devid, dev_uuid, fs_uuid);
3280         if (!device || !device->bdev) {
3281                 if (!btrfs_test_opt(root, DEGRADED))
3282                         return -EIO;
3283
3284                 if (!device) {
3285                         printk(KERN_WARNING "warning devid %llu missing\n",
3286                                (unsigned long long)devid);
3287                         device = add_missing_dev(root, devid, dev_uuid);
3288                         if (!device)
3289                                 return -ENOMEM;
3290                 }
3291         }
3292
3293         if (device->fs_devices != root->fs_info->fs_devices) {
3294                 BUG_ON(device->writeable);
3295                 if (device->generation !=
3296                     btrfs_device_generation(leaf, dev_item))
3297                         return -EINVAL;
3298         }
3299
3300         fill_device_from_item(leaf, dev_item, device);
3301         device->dev_root = root->fs_info->dev_root;
3302         device->in_fs_metadata = 1;
3303         if (device->writeable)
3304                 device->fs_devices->total_rw_bytes += device->total_bytes;
3305         ret = 0;
3306         return ret;
3307 }
3308
3309 int btrfs_read_super_device(struct btrfs_root *root, struct extent_buffer *buf)
3310 {
3311         struct btrfs_dev_item *dev_item;
3312
3313         dev_item = (struct btrfs_dev_item *)offsetof(struct btrfs_super_block,
3314                                                      dev_item);
3315         return read_one_dev(root, buf, dev_item);
3316 }
3317
3318 int btrfs_read_sys_array(struct btrfs_root *root)
3319 {
3320         struct btrfs_super_block *super_copy = &root->fs_info->super_copy;
3321         struct extent_buffer *sb;
3322         struct btrfs_disk_key *disk_key;
3323         struct btrfs_chunk *chunk;
3324         u8 *ptr;
3325         unsigned long sb_ptr;
3326         int ret = 0;
3327         u32 num_stripes;
3328         u32 array_size;
3329         u32 len = 0;
3330         u32 cur;
3331         struct btrfs_key key;
3332
3333         sb = btrfs_find_create_tree_block(root, BTRFS_SUPER_INFO_OFFSET,
3334                                           BTRFS_SUPER_INFO_SIZE);
3335         if (!sb)
3336                 return -ENOMEM;
3337         btrfs_set_buffer_uptodate(sb);
3338         btrfs_set_buffer_lockdep_class(sb, 0);
3339
3340         write_extent_buffer(sb, super_copy, 0, BTRFS_SUPER_INFO_SIZE);
3341         array_size = btrfs_super_sys_array_size(super_copy);
3342
3343         ptr = super_copy->sys_chunk_array;
3344         sb_ptr = offsetof(struct btrfs_super_block, sys_chunk_array);
3345         cur = 0;
3346
3347         while (cur < array_size) {
3348                 disk_key = (struct btrfs_disk_key *)ptr;
3349                 btrfs_disk_key_to_cpu(&key, disk_key);
3350
3351                 len = sizeof(*disk_key); ptr += len;
3352                 sb_ptr += len;
3353                 cur += len;
3354
3355                 if (key.type == BTRFS_CHUNK_ITEM_KEY) {
3356                         chunk = (struct btrfs_chunk *)sb_ptr;
3357                         ret = read_one_chunk(root, &key, sb, chunk);
3358                         if (ret)
3359                                 break;
3360                         num_stripes = btrfs_chunk_num_stripes(sb, chunk);
3361                         len = btrfs_chunk_item_size(num_stripes);
3362                 } else {
3363                         ret = -EIO;
3364                         break;
3365                 }
3366                 ptr += len;
3367                 sb_ptr += len;
3368                 cur += len;
3369         }
3370         free_extent_buffer(sb);
3371         return ret;
3372 }
3373
3374 int btrfs_read_chunk_tree(struct btrfs_root *root)
3375 {
3376         struct btrfs_path *path;
3377         struct extent_buffer *leaf;
3378         struct btrfs_key key;
3379         struct btrfs_key found_key;
3380         int ret;
3381         int slot;
3382
3383         root = root->fs_info->chunk_root;
3384
3385         path = btrfs_alloc_path();
3386         if (!path)
3387                 return -ENOMEM;
3388
3389         /* first we search for all of the device items, and then we
3390          * read in all of the chunk items.  This way we can create chunk
3391          * mappings that reference all of the devices that are afound
3392          */
3393         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
3394         key.offset = 0;
3395         key.type = 0;
3396 again:
3397         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3398         if (ret < 0)
3399                 goto error;
3400         while (1) {
3401                 leaf = path->nodes[0];
3402                 slot = path->slots[0];
3403                 if (slot >= btrfs_header_nritems(leaf)) {
3404                         ret = btrfs_next_leaf(root, path);
3405                         if (ret == 0)
3406                                 continue;
3407                         if (ret < 0)
3408                                 goto error;
3409                         break;
3410                 }
3411                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
3412                 if (key.objectid == BTRFS_DEV_ITEMS_OBJECTID) {
3413                         if (found_key.objectid != BTRFS_DEV_ITEMS_OBJECTID)
3414                                 break;
3415                         if (found_key.type == BTRFS_DEV_ITEM_KEY) {
3416                                 struct btrfs_dev_item *dev_item;
3417                                 dev_item = btrfs_item_ptr(leaf, slot,
3418                                                   struct btrfs_dev_item);
3419                                 ret = read_one_dev(root, leaf, dev_item);
3420                                 if (ret)
3421                                         goto error;
3422                         }
3423                 } else if (found_key.type == BTRFS_CHUNK_ITEM_KEY) {
3424                         struct btrfs_chunk *chunk;
3425                         chunk = btrfs_item_ptr(leaf, slot, struct btrfs_chunk);
3426                         ret = read_one_chunk(root, &found_key, leaf, chunk);
3427                         if (ret)
3428                                 goto error;
3429                 }
3430                 path->slots[0]++;
3431         }
3432         if (key.objectid == BTRFS_DEV_ITEMS_OBJECTID) {
3433                 key.objectid = 0;
3434                 btrfs_release_path(root, path);
3435                 goto again;
3436         }
3437         ret = 0;
3438 error:
3439         btrfs_free_path(path);
3440         return ret;
3441 }