drivers/block/rbd.c

   1 /*
   2    rbd.c -- Export ceph rados objects as a Linux block device
   3
   4
   5    based on drivers/block/osdblk.c:
   6
   7    Copyright 2009 Red Hat, Inc.
   8
   9    This program is free software; you can redistribute it and/or modify
  10    it under the terms of the GNU General Public License as published by
  11    the Free Software Foundation.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program; see the file COPYING.  If not, write to
  20    the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
  21
  22
  23
  24    For usage instructions, please refer to:
  25
  26                  Documentation/ABI/testing/sysfs-bus-rbd
  27
  28  */
  29
  30 #include <linux/ceph/libceph.h>
  31 #include <linux/ceph/osd_client.h>
  32 #include <linux/ceph/mon_client.h>
  33 #include <linux/ceph/decode.h>
  34 #include <linux/parser.h>
  35
  36 #include <linux/kernel.h>
  37 #include <linux/device.h>
  38 #include <linux/module.h>
  39 #include <linux/fs.h>
  40 #include <linux/blkdev.h>
  41
  42 #include "rbd_types.h"
  43
  44 #define DRV_NAME "rbd"
  45 #define DRV_NAME_LONG "rbd (rados block device)"
  46
  47 #define RBD_MINORS_PER_MAJOR    256             /* max minors per blkdev */
  48
  49 #define RBD_MAX_MD_NAME_LEN     (96 + sizeof(RBD_SUFFIX))
  50 #define RBD_MAX_POOL_NAME_LEN   64
  51 #define RBD_MAX_SNAP_NAME_LEN   32
  52 #define RBD_MAX_OPT_LEN         1024
  53
  54 #define RBD_SNAP_HEAD_NAME      "-"
  55
  56 #define DEV_NAME_LEN            32
  57
  58 #define RBD_NOTIFY_TIMEOUT_DEFAULT 10
  59
  60 /*
  61  * block device image metadata (in-memory version)
  62  */
  63 struct rbd_image_header {
  64         u64 image_size;
  65         char block_name[32];
  66         __u8 obj_order;
  67         __u8 crypt_type;
  68         __u8 comp_type;
  69         struct rw_semaphore snap_rwsem;
  70         struct ceph_snap_context *snapc;
  71         size_t snap_names_len;
  72         u64 snap_seq;
  73         u32 total_snaps;
  74
  75         char *snap_names;
  76         u64 *snap_sizes;
  77
  78         u64 obj_version;
  79 };
  80
  81 struct rbd_options {
  82         int     notify_timeout;
  83 };
  84
  85 /*
  86  * an instance of the client.  multiple devices may share a client.
  87  */
  88 struct rbd_client {
  89         struct ceph_client      *client;
  90         struct rbd_options      *rbd_opts;
  91         struct kref             kref;
  92         struct list_head        node;
  93 };
  94
  95 struct rbd_req_coll;
  96
  97 /*
  98  * a single io request
  99  */
 100 struct rbd_request {
 101         struct request          *rq;            /* blk layer request */
 102         struct bio              *bio;           /* cloned bio */
 103         struct page             **pages;        /* list of used pages */
 104         u64                     len;
 105         int                     coll_index;
 106         struct rbd_req_coll     *coll;
 107 };
 108
 109 struct rbd_req_status {
 110         int done;
 111         int rc;
 112         u64 bytes;
 113 };
 114
 115 /*
 116  * a collection of requests
 117  */
 118 struct rbd_req_coll {
 119         int                     total;
 120         int                     num_done;
 121         struct kref             kref;
 122         struct rbd_req_status   status[0];
 123 };
 124
 125 struct rbd_snap {
 126         struct  device          dev;
 127         const char              *name;
 128         size_t                  size;
 129         struct list_head        node;
 130         u64                     id;
 131 };
 132
 133 /*
 134  * a single device
 135  */
 136 struct rbd_device {
 137         int                     id;             /* blkdev unique id */
 138
 139         int                     major;          /* blkdev assigned major */
 140         struct gendisk          *disk;          /* blkdev's gendisk and rq */
 141         struct request_queue    *q;
 142
 143         struct ceph_client      *client;
 144         struct rbd_client       *rbd_client;
 145
 146         char                    name[DEV_NAME_LEN]; /* blkdev name, e.g. rbd3 */
 147
 148         spinlock_t              lock;           /* queue lock */
 149
 150         struct rbd_image_header header;
 151         char                    obj[RBD_MAX_OBJ_NAME_LEN]; /* rbd image name */
 152         int                     obj_len;
 153         char                    obj_md_name[RBD_MAX_MD_NAME_LEN]; /* hdr nm. */
 154         char                    pool_name[RBD_MAX_POOL_NAME_LEN];
 155         int                     poolid;
 156
 157         struct ceph_osd_event   *watch_event;
 158         struct ceph_osd_request *watch_request;
 159
 160         char                    snap_name[RBD_MAX_SNAP_NAME_LEN];
 161         u32 cur_snap;   /* index+1 of current snapshot within snap context
 162                            0 - for the head */
 163         int read_only;
 164
 165         struct list_head        node;
 166
 167         /* list of snapshots */
 168         struct list_head        snaps;
 169
 170         /* sysfs related */
 171         struct device           dev;
 172 };
 173
 174 static struct bus_type rbd_bus_type = {
 175         .name           = "rbd",
 176 };
 177
 178 static spinlock_t node_lock;      /* protects client get/put */
 179
 180 static DEFINE_MUTEX(ctl_mutex);   /* Serialize open/close/setup/teardown */
 181 static LIST_HEAD(rbd_dev_list);    /* devices */
 182 static LIST_HEAD(rbd_client_list);      /* clients */
 183
 184 static int __rbd_init_snaps_header(struct rbd_device *rbd_dev);
 185 static void rbd_dev_release(struct device *dev);
 186 static ssize_t rbd_snap_rollback(struct device *dev,
 187                                  struct device_attribute *attr,
 188                                  const char *buf,
 189                                  size_t size);
 190 static ssize_t rbd_snap_add(struct device *dev,
 191                             struct device_attribute *attr,
 192                             const char *buf,
 193                             size_t count);
 194 static void __rbd_remove_snap_dev(struct rbd_device *rbd_dev,
 195                                   struct rbd_snap *snap);;
 196
 197
 198 static struct rbd_device *dev_to_rbd(struct device *dev)
 199 {
 200         return container_of(dev, struct rbd_device, dev);
 201 }
 202
 203 static struct device *rbd_get_dev(struct rbd_device *rbd_dev)
 204 {
 205         return get_device(&rbd_dev->dev);
 206 }
 207
 208 static void rbd_put_dev(struct rbd_device *rbd_dev)
 209 {
 210         put_device(&rbd_dev->dev);
 211 }
 212
 213 static int __rbd_update_snaps(struct rbd_device *rbd_dev);
 214
 215 static int rbd_open(struct block_device *bdev, fmode_t mode)
 216 {
 217         struct gendisk *disk = bdev->bd_disk;
 218         struct rbd_device *rbd_dev = disk->private_data;
 219
 220         rbd_get_dev(rbd_dev);
 221
 222         set_device_ro(bdev, rbd_dev->read_only);
 223
 224         if ((mode & FMODE_WRITE) && rbd_dev->read_only)
 225                 return -EROFS;
 226
 227         return 0;
 228 }
 229
 230 static int rbd_release(struct gendisk *disk, fmode_t mode)
 231 {
 232         struct rbd_device *rbd_dev = disk->private_data;
 233
 234         rbd_put_dev(rbd_dev);
 235
 236         return 0;
 237 }
 238
 239 static const struct block_device_operations rbd_bd_ops = {
 240         .owner                  = THIS_MODULE,
 241         .open                   = rbd_open,
 242         .release                = rbd_release,
 243 };
 244
 245 /*
 246  * Initialize an rbd client instance.
 247  * We own *opt.
 248  */
 249 static struct rbd_client *rbd_client_create(struct ceph_options *opt,
 250                                             struct rbd_options *rbd_opts)
 251 {
 252         struct rbd_client *rbdc;
 253         int ret = -ENOMEM;
 254
 255         dout("rbd_client_create\n");
 256         rbdc = kmalloc(sizeof(struct rbd_client), GFP_KERNEL);
 257         if (!rbdc)
 258                 goto out_opt;
 259
 260         kref_init(&rbdc->kref);
 261         INIT_LIST_HEAD(&rbdc->node);
 262
 263         rbdc->client = ceph_create_client(opt, rbdc);
 264         if (IS_ERR(rbdc->client))
 265                 goto out_rbdc;
 266         opt = NULL; /* Now rbdc->client is responsible for opt */
 267
 268         ret = ceph_open_session(rbdc->client);
 269         if (ret < 0)
 270                 goto out_err;
 271
 272         rbdc->rbd_opts = rbd_opts;
 273
 274         spin_lock(&node_lock);
 275         list_add_tail(&rbdc->node, &rbd_client_list);
 276         spin_unlock(&node_lock);
 277
 278         dout("rbd_client_create created %p\n", rbdc);
 279         return rbdc;
 280
 281 out_err:
 282         ceph_destroy_client(rbdc->client);
 283 out_rbdc:
 284         kfree(rbdc);
 285 out_opt:
 286         if (opt)
 287                 ceph_destroy_options(opt);
 288         return ERR_PTR(ret);
 289 }
 290
 291 /*
 292  * Find a ceph client with specific addr and configuration.
 293  */
 294 static struct rbd_client *__rbd_client_find(struct ceph_options *opt)
 295 {
 296         struct rbd_client *client_node;
 297
 298         if (opt->flags & CEPH_OPT_NOSHARE)
 299                 return NULL;
 300
 301         list_for_each_entry(client_node, &rbd_client_list, node)
 302                 if (ceph_compare_options(opt, client_node->client) == 0)
 303                         return client_node;
 304         return NULL;
 305 }
 306
 307 /*
 308  * mount options
 309  */
 310 enum {
 311         Opt_notify_timeout,
 312         Opt_last_int,
 313         /* int args above */
 314         Opt_last_string,
 315         /* string args above */
 316 };
 317
 318 static match_table_t rbdopt_tokens = {
 319         {Opt_notify_timeout, "notify_timeout=%d"},
 320         /* int args above */
 321         /* string args above */
 322         {-1, NULL}
 323 };
 324
 325 static int parse_rbd_opts_token(char *c, void *private)
 326 {
 327         struct rbd_options *rbdopt = private;
 328         substring_t argstr[MAX_OPT_ARGS];
 329         int token, intval, ret;
 330
 331         token = match_token((char *)c, rbdopt_tokens, argstr);
 332         if (token < 0)
 333                 return -EINVAL;
 334
 335         if (token < Opt_last_int) {
 336                 ret = match_int(&argstr[0], &intval);
 337                 if (ret < 0) {
 338                         pr_err("bad mount option arg (not int) "
 339                                "at '%s'\n", c);
 340                         return ret;
 341                 }
 342                 dout("got int token %d val %d\n", token, intval);
 343         } else if (token > Opt_last_int && token < Opt_last_string) {
 344                 dout("got string token %d val %s\n", token,
 345                      argstr[0].from);
 346         } else {
 347                 dout("got token %d\n", token);
 348         }
 349
 350         switch (token) {
 351         case Opt_notify_timeout:
 352                 rbdopt->notify_timeout = intval;
 353                 break;
 354         default:
 355                 BUG_ON(token);
 356         }
 357         return 0;
 358 }
 359
 360 /*
 361  * Get a ceph client with specific addr and configuration, if one does
 362  * not exist create it.
 363  */
 364 static int rbd_get_client(struct rbd_device *rbd_dev, const char *mon_addr,
 365                           char *options)
 366 {
 367         struct rbd_client *rbdc;
 368         struct ceph_options *opt;
 369         int ret;
 370         struct rbd_options *rbd_opts;
 371
 372         rbd_opts = kzalloc(sizeof(*rbd_opts), GFP_KERNEL);
 373         if (!rbd_opts)
 374                 return -ENOMEM;
 375
 376         rbd_opts->notify_timeout = RBD_NOTIFY_TIMEOUT_DEFAULT;
 377
 378         ret = ceph_parse_options(&opt, options, mon_addr,
 379                                  mon_addr + strlen(mon_addr), parse_rbd_opts_token, rbd_opts);
 380         if (ret < 0)
 381                 goto done_err;
 382
 383         spin_lock(&node_lock);
 384         rbdc = __rbd_client_find(opt);
 385         if (rbdc) {
 386                 ceph_destroy_options(opt);
 387
 388                 /* using an existing client */
 389                 kref_get(&rbdc->kref);
 390                 rbd_dev->rbd_client = rbdc;
 391                 rbd_dev->client = rbdc->client;
 392                 spin_unlock(&node_lock);
 393                 return 0;
 394         }
 395         spin_unlock(&node_lock);
 396
 397         rbdc = rbd_client_create(opt, rbd_opts);
 398         if (IS_ERR(rbdc)) {
 399                 ret = PTR_ERR(rbdc);
 400                 goto done_err;
 401         }
 402
 403         rbd_dev->rbd_client = rbdc;
 404         rbd_dev->client = rbdc->client;
 405         return 0;
 406 done_err:
 407         kfree(rbd_opts);
 408         return ret;
 409 }
 410
 411 /*
 412  * Destroy ceph client
 413  */
 414 static void rbd_client_release(struct kref *kref)
 415 {
 416         struct rbd_client *rbdc = container_of(kref, struct rbd_client, kref);
 417
 418         dout("rbd_release_client %p\n", rbdc);
 419         spin_lock(&node_lock);
 420         list_del(&rbdc->node);
 421         spin_unlock(&node_lock);
 422
 423         ceph_destroy_client(rbdc->client);
 424         kfree(rbdc->rbd_opts);
 425         kfree(rbdc);
 426 }
 427
 428 /*
 429  * Drop reference to ceph client node. If it's not referenced anymore, release
 430  * it.
 431  */
 432 static void rbd_put_client(struct rbd_device *rbd_dev)
 433 {
 434         kref_put(&rbd_dev->rbd_client->kref, rbd_client_release);
 435         rbd_dev->rbd_client = NULL;
 436         rbd_dev->client = NULL;
 437 }
 438
 439 /*
 440  * Destroy requests collection
 441  */
 442 static void rbd_coll_release(struct kref *kref)
 443 {
 444         struct rbd_req_coll *coll =
 445                 container_of(kref, struct rbd_req_coll, kref);
 446
 447         dout("rbd_coll_release %p\n", coll);
 448         kfree(coll);
 449 }
 450
 451 /*
 452  * Create a new header structure, translate header format from the on-disk
 453  * header.
 454  */
 455 static int rbd_header_from_disk(struct rbd_image_header *header,
 456                                  struct rbd_image_header_ondisk *ondisk,
 457                                  int allocated_snaps,
 458                                  gfp_t gfp_flags)
 459 {
 460         int i;
 461         u32 snap_count = le32_to_cpu(ondisk->snap_count);
 462         int ret = -ENOMEM;
 463
 464         init_rwsem(&header->snap_rwsem);
 465         header->snap_names_len = le64_to_cpu(ondisk->snap_names_len);
 466         header->snapc = kmalloc(sizeof(struct ceph_snap_context) +
 467                                 snap_count *
 468                                  sizeof(struct rbd_image_snap_ondisk),
 469                                 gfp_flags);
 470         if (!header->snapc)
 471                 return -ENOMEM;
 472         if (snap_count) {
 473                 header->snap_names = kmalloc(header->snap_names_len,
 474                                              GFP_KERNEL);
 475                 if (!header->snap_names)
 476                         goto err_snapc;
 477                 header->snap_sizes = kmalloc(snap_count * sizeof(u64),
 478                                              GFP_KERNEL);
 479                 if (!header->snap_sizes)
 480                         goto err_names;
 481         } else {
 482                 header->snap_names = NULL;
 483                 header->snap_sizes = NULL;
 484         }
 485         memcpy(header->block_name, ondisk->block_name,
 486                sizeof(ondisk->block_name));
 487
 488         header->image_size = le64_to_cpu(ondisk->image_size);
 489         header->obj_order = ondisk->options.order;
 490         header->crypt_type = ondisk->options.crypt_type;
 491         header->comp_type = ondisk->options.comp_type;
 492
 493         atomic_set(&header->snapc->nref, 1);
 494         header->snap_seq = le64_to_cpu(ondisk->snap_seq);
 495         header->snapc->num_snaps = snap_count;
 496         header->total_snaps = snap_count;
 497
 498         if (snap_count &&
 499             allocated_snaps == snap_count) {
 500                 for (i = 0; i < snap_count; i++) {
 501                         header->snapc->snaps[i] =
 502                                 le64_to_cpu(ondisk->snaps[i].id);
 503                         header->snap_sizes[i] =
 504                                 le64_to_cpu(ondisk->snaps[i].image_size);
 505                 }
 506
 507                 /* copy snapshot names */
 508                 memcpy(header->snap_names, &ondisk->snaps[i],
 509                         header->snap_names_len);
 510         }
 511
 512         return 0;
 513
 514 err_names:
 515         kfree(header->snap_names);
 516 err_snapc:
 517         kfree(header->snapc);
 518         return ret;
 519 }
 520
 521 static int snap_index(struct rbd_image_header *header, int snap_num)
 522 {
 523         return header->total_snaps - snap_num;
 524 }
 525
 526 static u64 cur_snap_id(struct rbd_device *rbd_dev)
 527 {
 528         struct rbd_image_header *header = &rbd_dev->header;
 529
 530         if (!rbd_dev->cur_snap)
 531                 return 0;
 532
 533         return header->snapc->snaps[snap_index(header, rbd_dev->cur_snap)];
 534 }
 535
 536 static int snap_by_name(struct rbd_image_header *header, const char *snap_name,
 537                         u64 *seq, u64 *size)
 538 {
 539         int i;
 540         char *p = header->snap_names;
 541
 542         for (i = 0; i < header->total_snaps; i++, p += strlen(p) + 1) {
 543                 if (strcmp(snap_name, p) == 0)
 544                         break;
 545         }
 546         if (i == header->total_snaps)
 547                 return -ENOENT;
 548         if (seq)
 549                 *seq = header->snapc->snaps[i];
 550
 551         if (size)
 552                 *size = header->snap_sizes[i];
 553
 554         return i;
 555 }
 556
 557 static int rbd_header_set_snap(struct rbd_device *dev,
 558                                const char *snap_name,
 559                                u64 *size)
 560 {
 561         struct rbd_image_header *header = &dev->header;
 562         struct ceph_snap_context *snapc = header->snapc;
 563         int ret = -ENOENT;
 564
 565         down_write(&header->snap_rwsem);
 566
 567         if (!snap_name ||
 568             !*snap_name ||
 569             strcmp(snap_name, "-") == 0 ||
 570             strcmp(snap_name, RBD_SNAP_HEAD_NAME) == 0) {
 571                 if (header->total_snaps)
 572                         snapc->seq = header->snap_seq;
 573                 else
 574                         snapc->seq = 0;
 575                 dev->cur_snap = 0;
 576                 dev->read_only = 0;
 577                 if (size)
 578                         *size = header->image_size;
 579         } else {
 580                 ret = snap_by_name(header, snap_name, &snapc->seq, size);
 581                 if (ret < 0)
 582                         goto done;
 583
 584                 dev->cur_snap = header->total_snaps - ret;
 585                 dev->read_only = 1;
 586         }
 587
 588         ret = 0;
 589 done:
 590         up_write(&header->snap_rwsem);
 591         return ret;
 592 }
 593
 594 static void rbd_header_free(struct rbd_image_header *header)
 595 {
 596         kfree(header->snapc);
 597         kfree(header->snap_names);
 598         kfree(header->snap_sizes);
 599 }
 600
 601 /*
 602  * get the actual striped segment name, offset and length
 603  */
 604 static u64 rbd_get_segment(struct rbd_image_header *header,
 605                            const char *block_name,
 606                            u64 ofs, u64 len,
 607                            char *seg_name, u64 *segofs)
 608 {
 609         u64 seg = ofs >> header->obj_order;
 610
 611         if (seg_name)
 612                 snprintf(seg_name, RBD_MAX_SEG_NAME_LEN,
 613                          "%s.%012llx", block_name, seg);
 614
 615         ofs = ofs & ((1 << header->obj_order) - 1);
 616         len = min_t(u64, len, (1 << header->obj_order) - ofs);
 617
 618         if (segofs)
 619                 *segofs = ofs;
 620
 621         return len;
 622 }
 623
 624 static int rbd_get_num_segments(struct rbd_image_header *header,
 625                                 u64 ofs, u64 len)
 626 {
 627         u64 start_seg = ofs >> header->obj_order;
 628         u64 end_seg = (ofs + len - 1) >> header->obj_order;
 629         return end_seg - start_seg + 1;
 630 }
 631
 632 /*
 633  * bio helpers
 634  */
 635
 636 static void bio_chain_put(struct bio *chain)
 637 {
 638         struct bio *tmp;
 639
 640         while (chain) {
 641                 tmp = chain;
 642                 chain = chain->bi_next;
 643                 bio_put(tmp);
 644         }
 645 }
 646
 647 /*
 648  * zeros a bio chain, starting at specific offset
 649  */
 650 static void zero_bio_chain(struct bio *chain, int start_ofs)
 651 {
 652         struct bio_vec *bv;
 653         unsigned long flags;
 654         void *buf;
 655         int i;
 656         int pos = 0;
 657
 658         while (chain) {
 659                 bio_for_each_segment(bv, chain, i) {
 660                         if (pos + bv->bv_len > start_ofs) {
 661                                 int remainder = max(start_ofs - pos, 0);
 662                                 buf = bvec_kmap_irq(bv, &flags);
 663                                 memset(buf + remainder, 0,
 664                                        bv->bv_len - remainder);
 665                                 bvec_kunmap_irq(buf, &flags);
 666                         }
 667                         pos += bv->bv_len;
 668                 }
 669
 670                 chain = chain->bi_next;
 671         }
 672 }
 673
 674 /*
 675  * bio_chain_clone - clone a chain of bios up to a certain length.
 676  * might return a bio_pair that will need to be released.
 677  */
 678 static struct bio *bio_chain_clone(struct bio **old, struct bio **next,
 679                                    struct bio_pair **bp,
 680                                    int len, gfp_t gfpmask)
 681 {
 682         struct bio *tmp, *old_chain = *old, *new_chain = NULL, *tail = NULL;
 683         int total = 0;
 684
 685         if (*bp) {
 686                 bio_pair_release(*bp);
 687                 *bp = NULL;
 688         }
 689
 690         while (old_chain && (total < len)) {
 691                 tmp = bio_kmalloc(gfpmask, old_chain->bi_max_vecs);
 692                 if (!tmp)
 693                         goto err_out;
 694
 695                 if (total + old_chain->bi_size > len) {
 696                         struct bio_pair *bp;
 697
 698                         /*
 699                          * this split can only happen with a single paged bio,
 700                          * split_bio will BUG_ON if this is not the case
 701                          */
 702                         dout("bio_chain_clone split! total=%d remaining=%d"
 703                              "bi_size=%d\n",
 704                              (int)total, (int)len-total,
 705                              (int)old_chain->bi_size);
 706
 707                         /* split the bio. We'll release it either in the next
 708                            call, or it will have to be released outside */
 709                         bp = bio_split(old_chain, (len - total) / 512ULL);
 710                         if (!bp)
 711                                 goto err_out;
 712
 713                         __bio_clone(tmp, &bp->bio1);
 714
 715                         *next = &bp->bio2;
 716                 } else {
 717                         __bio_clone(tmp, old_chain);
 718                         *next = old_chain->bi_next;
 719                 }
 720
 721                 tmp->bi_bdev = NULL;
 722                 gfpmask &= ~__GFP_WAIT;
 723                 tmp->bi_next = NULL;
 724
 725                 if (!new_chain) {
 726                         new_chain = tail = tmp;
 727                 } else {
 728                         tail->bi_next = tmp;
 729                         tail = tmp;
 730                 }
 731                 old_chain = old_chain->bi_next;
 732
 733                 total += tmp->bi_size;
 734         }
 735
 736         BUG_ON(total < len);
 737
 738         if (tail)
 739                 tail->bi_next = NULL;
 740
 741         *old = old_chain;
 742
 743         return new_chain;
 744
 745 err_out:
 746         dout("bio_chain_clone with err\n");
 747         bio_chain_put(new_chain);
 748         return NULL;
 749 }
 750
 751 /*
 752  * helpers for osd request op vectors.
 753  */
 754 static int rbd_create_rw_ops(struct ceph_osd_req_op **ops,
 755                             int num_ops,
 756                             int opcode,
 757                             u32 payload_len)
 758 {
 759         *ops = kzalloc(sizeof(struct ceph_osd_req_op) * (num_ops + 1),
 760                        GFP_NOIO);
 761         if (!*ops)
 762                 return -ENOMEM;
 763         (*ops)[0].op = opcode;
 764         /*
 765          * op extent offset and length will be set later on
 766          * in calc_raw_layout()
 767          */
 768         (*ops)[0].payload_len = payload_len;
 769         return 0;
 770 }
 771
 772 static void rbd_destroy_ops(struct ceph_osd_req_op *ops)
 773 {
 774         kfree(ops);
 775 }
 776
 777 static void rbd_coll_end_req_index(struct request *rq,
 778                                    struct rbd_req_coll *coll,
 779                                    int index,
 780                                    int ret, u64 len)
 781 {
 782         struct request_queue *q;
 783         int min, max, i;
 784
 785         dout("rbd_coll_end_req_index %p index %d ret %d len %lld\n",
 786              coll, index, ret, len);
 787
 788         if (!rq)
 789                 return;
 790
 791         if (!coll) {
 792                 blk_end_request(rq, ret, len);
 793                 return;
 794         }
 795
 796         q = rq->q;
 797
 798         spin_lock_irq(q->queue_lock);
 799         coll->status[index].done = 1;
 800         coll->status[index].rc = ret;
 801         coll->status[index].bytes = len;
 802         max = min = coll->num_done;
 803         while (max < coll->total && coll->status[max].done)
 804                 max++;
 805
 806         for (i = min; i<max; i++) {
 807                 __blk_end_request(rq, coll->status[i].rc,
 808                                   coll->status[i].bytes);
 809                 coll->num_done++;
 810                 kref_put(&coll->kref, rbd_coll_release);
 811         }
 812         spin_unlock_irq(q->queue_lock);
 813 }
 814
 815 static void rbd_coll_end_req(struct rbd_request *req,
 816                              int ret, u64 len)
 817 {
 818         rbd_coll_end_req_index(req->rq, req->coll, req->coll_index, ret, len);
 819 }
 820
 821 /*
 822  * Send ceph osd request
 823  */
 824 static int rbd_do_request(struct request *rq,
 825                           struct rbd_device *dev,
 826                           struct ceph_snap_context *snapc,
 827                           u64 snapid,
 828                           const char *obj, u64 ofs, u64 len,
 829                           struct bio *bio,
 830                           struct page **pages,
 831                           int num_pages,
 832                           int flags,
 833                           struct ceph_osd_req_op *ops,
 834                           int num_reply,
 835                           struct rbd_req_coll *coll,
 836                           int coll_index,
 837                           void (*rbd_cb)(struct ceph_osd_request *req,
 838                                          struct ceph_msg *msg),
 839                           struct ceph_osd_request **linger_req,
 840                           u64 *ver)
 841 {
 842         struct ceph_osd_request *req;
 843         struct ceph_file_layout *layout;
 844         int ret;
 845         u64 bno;
 846         struct timespec mtime = CURRENT_TIME;
 847         struct rbd_request *req_data;
 848         struct ceph_osd_request_head *reqhead;
 849         struct rbd_image_header *header = &dev->header;
 850
 851         req_data = kzalloc(sizeof(*req_data), GFP_NOIO);
 852         if (!req_data) {
 853                 if (coll)
 854                         rbd_coll_end_req_index(rq, coll, coll_index,
 855                                                -ENOMEM, len);
 856                 return -ENOMEM;
 857         }
 858
 859         if (coll) {
 860                 req_data->coll = coll;
 861                 req_data->coll_index = coll_index;
 862         }
 863
 864         dout("rbd_do_request obj=%s ofs=%lld len=%lld\n", obj, len, ofs);
 865
 866         down_read(&header->snap_rwsem);
 867
 868         req = ceph_osdc_alloc_request(&dev->client->osdc, flags,
 869                                       snapc,
 870                                       ops,
 871                                       false,
 872                                       GFP_NOIO, pages, bio);
 873         if (!req) {
 874                 up_read(&header->snap_rwsem);
 875                 ret = -ENOMEM;
 876                 goto done_pages;
 877         }
 878
 879         req->r_callback = rbd_cb;
 880
 881         req_data->rq = rq;
 882         req_data->bio = bio;
 883         req_data->pages = pages;
 884         req_data->len = len;
 885
 886         req->r_priv = req_data;
 887
 888         reqhead = req->r_request->front.iov_base;
 889         reqhead->snapid = cpu_to_le64(CEPH_NOSNAP);
 890
 891         strncpy(req->r_oid, obj, sizeof(req->r_oid));
 892         req->r_oid_len = strlen(req->r_oid);
 893
 894         layout = &req->r_file_layout;
 895         memset(layout, 0, sizeof(*layout));
 896         layout->fl_stripe_unit = cpu_to_le32(1 << RBD_MAX_OBJ_ORDER);
 897         layout->fl_stripe_count = cpu_to_le32(1);
 898         layout->fl_object_size = cpu_to_le32(1 << RBD_MAX_OBJ_ORDER);
 899         layout->fl_pg_preferred = cpu_to_le32(-1);
 900         layout->fl_pg_pool = cpu_to_le32(dev->poolid);
 901         ceph_calc_raw_layout(&dev->client->osdc, layout, snapid,
 902                              ofs, &len, &bno, req, ops);
 903
 904         ceph_osdc_build_request(req, ofs, &len,
 905                                 ops,
 906                                 snapc,
 907                                 &mtime,
 908                                 req->r_oid, req->r_oid_len);
 909         up_read(&header->snap_rwsem);
 910
 911         if (linger_req) {
 912                 ceph_osdc_set_request_linger(&dev->client->osdc, req);
 913                 *linger_req = req;
 914         }
 915
 916         ret = ceph_osdc_start_request(&dev->client->osdc, req, false);
 917         if (ret < 0)
 918                 goto done_err;
 919
 920         if (!rbd_cb) {
 921                 ret = ceph_osdc_wait_request(&dev->client->osdc, req);
 922                 if (ver)
 923                         *ver = le64_to_cpu(req->r_reassert_version.version);
 924                 dout("reassert_ver=%lld\n",
 925                      le64_to_cpu(req->r_reassert_version.version));
 926                 ceph_osdc_put_request(req);
 927         }
 928         return ret;
 929
 930 done_err:
 931         bio_chain_put(req_data->bio);
 932         ceph_osdc_put_request(req);
 933 done_pages:
 934         rbd_coll_end_req(req_data, ret, len);
 935         kfree(req_data);
 936         return ret;
 937 }
 938
 939 /*
 940  * Ceph osd op callback
 941  */
 942 static void rbd_req_cb(struct ceph_osd_request *req, struct ceph_msg *msg)
 943 {
 944         struct rbd_request *req_data = req->r_priv;
 945         struct ceph_osd_reply_head *replyhead;
 946         struct ceph_osd_op *op;
 947         __s32 rc;
 948         u64 bytes;
 949         int read_op;
 950
 951         /* parse reply */
 952         replyhead = msg->front.iov_base;
 953         WARN_ON(le32_to_cpu(replyhead->num_ops) == 0);
 954         op = (void *)(replyhead + 1);
 955         rc = le32_to_cpu(replyhead->result);
 956         bytes = le64_to_cpu(op->extent.length);
 957         read_op = (le32_to_cpu(op->op) == CEPH_OSD_OP_READ);
 958
 959         dout("rbd_req_cb bytes=%lld readop=%d rc=%d\n", bytes, read_op, rc);
 960
 961         if (rc == -ENOENT && read_op) {
 962                 zero_bio_chain(req_data->bio, 0);
 963                 rc = 0;
 964         } else if (rc == 0 && read_op && bytes < req_data->len) {
 965                 zero_bio_chain(req_data->bio, bytes);
 966                 bytes = req_data->len;
 967         }
 968
 969         rbd_coll_end_req(req_data, rc, bytes);
 970
 971         if (req_data->bio)
 972                 bio_chain_put(req_data->bio);
 973
 974         ceph_osdc_put_request(req);
 975         kfree(req_data);
 976 }
 977
 978 static void rbd_simple_req_cb(struct ceph_osd_request *req, struct ceph_msg *msg)
 979 {
 980         ceph_osdc_put_request(req);
 981 }
 982
 983 /*
 984  * Do a synchronous ceph osd operation
 985  */
 986 static int rbd_req_sync_op(struct rbd_device *dev,
 987                            struct ceph_snap_context *snapc,
 988                            u64 snapid,
 989                            int opcode,
 990                            int flags,
 991                            struct ceph_osd_req_op *orig_ops,
 992                            int num_reply,
 993                            const char *obj,
 994                            u64 ofs, u64 len,
 995                            char *buf,
 996                            struct ceph_osd_request **linger_req,
 997                            u64 *ver)
 998 {
 999         int ret;
1000         struct page **pages;
1001         int num_pages;
1002         struct ceph_osd_req_op *ops = orig_ops;
1003         u32 payload_len;
1004
1005         num_pages = calc_pages_for(ofs , len);
1006         pages = ceph_alloc_page_vector(num_pages, GFP_KERNEL);
1007         if (IS_ERR(pages))
1008                 return PTR_ERR(pages);
1009
1010         if (!orig_ops) {
1011                 payload_len = (flags & CEPH_OSD_FLAG_WRITE ? len : 0);
1012                 ret = rbd_create_rw_ops(&ops, 1, opcode, payload_len);
1013                 if (ret < 0)
1014                         goto done;
1015
1016                 if ((flags & CEPH_OSD_FLAG_WRITE) && buf) {
1017                         ret = ceph_copy_to_page_vector(pages, buf, ofs, len);
1018                         if (ret < 0)
1019                                 goto done_ops;
1020                 }
1021         }
1022
1023         ret = rbd_do_request(NULL, dev, snapc, snapid,
1024                           obj, ofs, len, NULL,
1025                           pages, num_pages,
1026                           flags,
1027                           ops,
1028                           2,
1029                           NULL, 0,
1030                           NULL,
1031                           linger_req, ver);
1032         if (ret < 0)
1033                 goto done_ops;
1034
1035         if ((flags & CEPH_OSD_FLAG_READ) && buf)
1036                 ret = ceph_copy_from_page_vector(pages, buf, ofs, ret);
1037
1038 done_ops:
1039         if (!orig_ops)
1040                 rbd_destroy_ops(ops);
1041 done:
1042         ceph_release_page_vector(pages, num_pages);
1043         return ret;
1044 }
1045
1046 /*
1047  * Do an asynchronous ceph osd operation
1048  */
1049 static int rbd_do_op(struct request *rq,
1050                      struct rbd_device *rbd_dev ,
1051                      struct ceph_snap_context *snapc,
1052                      u64 snapid,
1053                      int opcode, int flags, int num_reply,
1054                      u64 ofs, u64 len,
1055                      struct bio *bio,
1056                      struct rbd_req_coll *coll,
1057                      int coll_index)
1058 {
1059         char *seg_name;
1060         u64 seg_ofs;
1061         u64 seg_len;
1062         int ret;
1063         struct ceph_osd_req_op *ops;
1064         u32 payload_len;
1065
1066         seg_name = kmalloc(RBD_MAX_SEG_NAME_LEN + 1, GFP_NOIO);
1067         if (!seg_name)
1068                 return -ENOMEM;
1069
1070         seg_len = rbd_get_segment(&rbd_dev->header,
1071                                   rbd_dev->header.block_name,
1072                                   ofs, len,
1073                                   seg_name, &seg_ofs);
1074
1075         payload_len = (flags & CEPH_OSD_FLAG_WRITE ? seg_len : 0);
1076
1077         ret = rbd_create_rw_ops(&ops, 1, opcode, payload_len);
1078         if (ret < 0)
1079                 goto done;
1080
1081         /* we've taken care of segment sizes earlier when we
1082            cloned the bios. We should never have a segment
1083            truncated at this point */
1084         BUG_ON(seg_len < len);
1085
1086         ret = rbd_do_request(rq, rbd_dev, snapc, snapid,
1087                              seg_name, seg_ofs, seg_len,
1088                              bio,
1089                              NULL, 0,
1090                              flags,
1091                              ops,
1092                              num_reply,
1093                              coll, coll_index,
1094                              rbd_req_cb, 0, NULL);
1095
1096         rbd_destroy_ops(ops);
1097 done:
1098         kfree(seg_name);
1099         return ret;
1100 }
1101
1102 /*
1103  * Request async osd write
1104  */
1105 static int rbd_req_write(struct request *rq,
1106                          struct rbd_device *rbd_dev,
1107                          struct ceph_snap_context *snapc,
1108                          u64 ofs, u64 len,
1109                          struct bio *bio,
1110                          struct rbd_req_coll *coll,
1111                          int coll_index)
1112 {
1113         return rbd_do_op(rq, rbd_dev, snapc, CEPH_NOSNAP,
1114                          CEPH_OSD_OP_WRITE,
1115                          CEPH_OSD_FLAG_WRITE | CEPH_OSD_FLAG_ONDISK,
1116                          2,
1117                          ofs, len, bio, coll, coll_index);
1118 }
1119
1120 /*
1121  * Request async osd read
1122  */
1123 static int rbd_req_read(struct request *rq,
1124                          struct rbd_device *rbd_dev,
1125                          u64 snapid,
1126                          u64 ofs, u64 len,
1127                          struct bio *bio,
1128                          struct rbd_req_coll *coll,
1129                          int coll_index)
1130 {
1131         return rbd_do_op(rq, rbd_dev, NULL,
1132                          (snapid ? snapid : CEPH_NOSNAP),
1133                          CEPH_OSD_OP_READ,
1134                          CEPH_OSD_FLAG_READ,
1135                          2,
1136                          ofs, len, bio, coll, coll_index);
1137 }
1138
1139 /*
1140  * Request sync osd read
1141  */
1142 static int rbd_req_sync_read(struct rbd_device *dev,
1143                           struct ceph_snap_context *snapc,
1144                           u64 snapid,
1145                           const char *obj,
1146                           u64 ofs, u64 len,
1147                           char *buf,
1148                           u64 *ver)
1149 {
1150         return rbd_req_sync_op(dev, NULL,
1151                                (snapid ? snapid : CEPH_NOSNAP),
1152                                CEPH_OSD_OP_READ,
1153                                CEPH_OSD_FLAG_READ,
1154                                NULL,
1155                                1, obj, ofs, len, buf, NULL, ver);
1156 }
1157
1158 /*
1159  * Request sync osd watch
1160  */
1161 static int rbd_req_sync_notify_ack(struct rbd_device *dev,
1162                                    u64 ver,
1163                                    u64 notify_id,
1164                                    const char *obj)
1165 {
1166         struct ceph_osd_req_op *ops;
1167         struct page **pages = NULL;
1168         int ret;
1169
1170         ret = rbd_create_rw_ops(&ops, 1, CEPH_OSD_OP_NOTIFY_ACK, 0);
1171         if (ret < 0)
1172                 return ret;
1173
1174         ops[0].watch.ver = cpu_to_le64(dev->header.obj_version);
1175         ops[0].watch.cookie = notify_id;
1176         ops[0].watch.flag = 0;
1177
1178         ret = rbd_do_request(NULL, dev, NULL, CEPH_NOSNAP,
1179                           obj, 0, 0, NULL,
1180                           pages, 0,
1181                           CEPH_OSD_FLAG_READ,
1182                           ops,
1183                           1,
1184                           NULL, 0,
1185                           rbd_simple_req_cb, 0, NULL);
1186
1187         rbd_destroy_ops(ops);
1188         return ret;
1189 }
1190
1191 static void rbd_watch_cb(u64 ver, u64 notify_id, u8 opcode, void *data)
1192 {
1193         struct rbd_device *dev = (struct rbd_device *)data;
1194         int rc;
1195
1196         if (!dev)
1197                 return;
1198
1199         dout("rbd_watch_cb %s notify_id=%lld opcode=%d\n", dev->obj_md_name,
1200                 notify_id, (int)opcode);
1201         mutex_lock_nested(&ctl_mutex, SINGLE_DEPTH_NESTING);
1202         rc = __rbd_update_snaps(dev);
1203         mutex_unlock(&ctl_mutex);
1204         if (rc)
1205                 pr_warning(DRV_NAME "%d got notification but failed to update"
1206                            " snaps: %d\n", dev->major, rc);
1207
1208         rbd_req_sync_notify_ack(dev, ver, notify_id, dev->obj_md_name);
1209 }
1210
1211 /*
1212  * Request sync osd watch
1213  */
1214 static int rbd_req_sync_watch(struct rbd_device *dev,
1215                               const char *obj,
1216                               u64 ver)
1217 {
1218         struct ceph_osd_req_op *ops;
1219         struct ceph_osd_client *osdc = &dev->client->osdc;
1220
1221         int ret = rbd_create_rw_ops(&ops, 1, CEPH_OSD_OP_WATCH, 0);
1222         if (ret < 0)
1223                 return ret;
1224
1225         ret = ceph_osdc_create_event(osdc, rbd_watch_cb, 0,
1226                                      (void *)dev, &dev->watch_event);
1227         if (ret < 0)
1228                 goto fail;
1229
1230         ops[0].watch.ver = cpu_to_le64(ver);
1231         ops[0].watch.cookie = cpu_to_le64(dev->watch_event->cookie);
1232         ops[0].watch.flag = 1;
1233
1234         ret = rbd_req_sync_op(dev, NULL,
1235                               CEPH_NOSNAP,
1236                               0,
1237                               CEPH_OSD_FLAG_WRITE | CEPH_OSD_FLAG_ONDISK,
1238                               ops,
1239                               1, obj, 0, 0, NULL,
1240                               &dev->watch_request, NULL);
1241
1242         if (ret < 0)
1243                 goto fail_event;
1244
1245         rbd_destroy_ops(ops);
1246         return 0;
1247
1248 fail_event:
1249         ceph_osdc_cancel_event(dev->watch_event);
1250         dev->watch_event = NULL;
1251 fail:
1252         rbd_destroy_ops(ops);
1253         return ret;
1254 }
1255
1256 struct rbd_notify_info {
1257         struct rbd_device *dev;
1258 };
1259
1260 static void rbd_notify_cb(u64 ver, u64 notify_id, u8 opcode, void *data)
1261 {
1262         struct rbd_device *dev = (struct rbd_device *)data;
1263         if (!dev)
1264                 return;
1265
1266         dout("rbd_notify_cb %s notify_id=%lld opcode=%d\n", dev->obj_md_name,
1267                 notify_id, (int)opcode);
1268 }
1269
1270 /*
1271  * Request sync osd notify
1272  */
1273 static int rbd_req_sync_notify(struct rbd_device *dev,
1274                           const char *obj)
1275 {
1276         struct ceph_osd_req_op *ops;
1277         struct ceph_osd_client *osdc = &dev->client->osdc;
1278         struct ceph_osd_event *event;
1279         struct rbd_notify_info info;
1280         int payload_len = sizeof(u32) + sizeof(u32);
1281         int ret;
1282
1283         ret = rbd_create_rw_ops(&ops, 1, CEPH_OSD_OP_NOTIFY, payload_len);
1284         if (ret < 0)
1285                 return ret;
1286
1287         info.dev = dev;
1288
1289         ret = ceph_osdc_create_event(osdc, rbd_notify_cb, 1,
1290                                      (void *)&info, &event);
1291         if (ret < 0)
1292                 goto fail;
1293
1294         ops[0].watch.ver = 1;
1295         ops[0].watch.flag = 1;
1296         ops[0].watch.cookie = event->cookie;
1297         ops[0].watch.prot_ver = RADOS_NOTIFY_VER;
1298         ops[0].watch.timeout = 12;
1299
1300         ret = rbd_req_sync_op(dev, NULL,
1301                                CEPH_NOSNAP,
1302                                0,
1303                                CEPH_OSD_FLAG_WRITE | CEPH_OSD_FLAG_ONDISK,
1304                                ops,
1305                                1, obj, 0, 0, NULL, NULL, NULL);
1306         if (ret < 0)
1307                 goto fail_event;
1308
1309         ret = ceph_osdc_wait_event(event, CEPH_OSD_TIMEOUT_DEFAULT);
1310         dout("ceph_osdc_wait_event returned %d\n", ret);
1311         rbd_destroy_ops(ops);
1312         return 0;
1313
1314 fail_event:
1315         ceph_osdc_cancel_event(event);
1316 fail:
1317         rbd_destroy_ops(ops);
1318         return ret;
1319 }
1320
1321 /*
1322  * Request sync osd rollback
1323  */
1324 static int rbd_req_sync_rollback_obj(struct rbd_device *dev,
1325                                      u64 snapid,
1326                                      const char *obj)
1327 {
1328         struct ceph_osd_req_op *ops;
1329         int ret = rbd_create_rw_ops(&ops, 1, CEPH_OSD_OP_ROLLBACK, 0);
1330         if (ret < 0)
1331                 return ret;
1332
1333         ops[0].snap.snapid = snapid;
1334
1335         ret = rbd_req_sync_op(dev, NULL,
1336                                CEPH_NOSNAP,
1337                                0,
1338                                CEPH_OSD_FLAG_WRITE | CEPH_OSD_FLAG_ONDISK,
1339                                ops,
1340                                1, obj, 0, 0, NULL, NULL, NULL);
1341
1342         rbd_destroy_ops(ops);
1343
1344         return ret;
1345 }
1346
1347 /*
1348  * Request sync osd read
1349  */
1350 static int rbd_req_sync_exec(struct rbd_device *dev,
1351                              const char *obj,
1352                              const char *cls,
1353                              const char *method,
1354                              const char *data,
1355                              int len,
1356                              u64 *ver)
1357 {
1358         struct ceph_osd_req_op *ops;
1359         int cls_len = strlen(cls);
1360         int method_len = strlen(method);
1361         int ret = rbd_create_rw_ops(&ops, 1, CEPH_OSD_OP_CALL,
1362                                     cls_len + method_len + len);
1363         if (ret < 0)
1364                 return ret;
1365
1366         ops[0].cls.class_name = cls;
1367         ops[0].cls.class_len = (__u8)cls_len;
1368         ops[0].cls.method_name = method;
1369         ops[0].cls.method_len = (__u8)method_len;
1370         ops[0].cls.argc = 0;
1371         ops[0].cls.indata = data;
1372         ops[0].cls.indata_len = len;
1373
1374         ret = rbd_req_sync_op(dev, NULL,
1375                                CEPH_NOSNAP,
1376                                0,
1377                                CEPH_OSD_FLAG_WRITE | CEPH_OSD_FLAG_ONDISK,
1378                                ops,
1379                                1, obj, 0, 0, NULL, NULL, ver);
1380
1381         rbd_destroy_ops(ops);
1382
1383         dout("cls_exec returned %d\n", ret);
1384         return ret;
1385 }
1386
1387 static struct rbd_req_coll *rbd_alloc_coll(int num_reqs)
1388 {
1389         struct rbd_req_coll *coll =
1390                         kzalloc(sizeof(struct rbd_req_coll) +
1391                                 sizeof(struct rbd_req_status) * num_reqs,
1392                                 GFP_ATOMIC);
1393
1394         if (!coll)
1395                 return NULL;
1396         coll->total = num_reqs;
1397         kref_init(&coll->kref);
1398         return coll;
1399 }
1400
1401 /*
1402  * block device queue callback
1403  */
1404 static void rbd_rq_fn(struct request_queue *q)
1405 {
1406         struct rbd_device *rbd_dev = q->queuedata;
1407         struct request *rq;
1408         struct bio_pair *bp = NULL;
1409
1410         rq = blk_fetch_request(q);
1411
1412         while (1) {
1413                 struct bio *bio;
1414                 struct bio *rq_bio, *next_bio = NULL;
1415                 bool do_write;
1416                 int size, op_size = 0;
1417                 u64 ofs;
1418                 int num_segs, cur_seg = 0;
1419                 struct rbd_req_coll *coll;
1420
1421                 /* peek at request from block layer */
1422                 if (!rq)
1423                         break;
1424
1425                 dout("fetched request\n");
1426
1427                 /* filter out block requests we don't understand */
1428                 if ((rq->cmd_type != REQ_TYPE_FS)) {
1429                         __blk_end_request_all(rq, 0);
1430                         goto next;
1431                 }
1432
1433                 /* deduce our operation (read, write) */
1434                 do_write = (rq_data_dir(rq) == WRITE);
1435
1436                 size = blk_rq_bytes(rq);
1437                 ofs = blk_rq_pos(rq) * 512ULL;
1438                 rq_bio = rq->bio;
1439                 if (do_write && rbd_dev->read_only) {
1440                         __blk_end_request_all(rq, -EROFS);
1441                         goto next;
1442                 }
1443
1444                 spin_unlock_irq(q->queue_lock);
1445
1446                 dout("%s 0x%x bytes at 0x%llx\n",
1447                      do_write ? "write" : "read",
1448                      size, blk_rq_pos(rq) * 512ULL);
1449
1450                 num_segs = rbd_get_num_segments(&rbd_dev->header, ofs, size);
1451                 coll = rbd_alloc_coll(num_segs);
1452                 if (!coll) {
1453                         spin_lock_irq(q->queue_lock);
1454                         __blk_end_request_all(rq, -ENOMEM);
1455                         goto next;
1456                 }
1457
1458                 do {
1459                         /* a bio clone to be passed down to OSD req */
1460                         dout("rq->bio->bi_vcnt=%d\n", rq->bio->bi_vcnt);
1461                         op_size = rbd_get_segment(&rbd_dev->header,
1462                                                   rbd_dev->header.block_name,
1463                                                   ofs, size,
1464                                                   NULL, NULL);
1465                         kref_get(&coll->kref);
1466                         bio = bio_chain_clone(&rq_bio, &next_bio, &bp,
1467                                               op_size, GFP_ATOMIC);
1468                         if (!bio) {
1469                                 rbd_coll_end_req_index(rq, coll, cur_seg,
1470                                                        -ENOMEM, op_size);
1471                                 goto next_seg;
1472                         }
1473
1474
1475                         /* init OSD command: write or read */
1476                         if (do_write)
1477                                 rbd_req_write(rq, rbd_dev,
1478                                               rbd_dev->header.snapc,
1479                                               ofs,
1480                                               op_size, bio,
1481                                               coll, cur_seg);
1482                         else
1483                                 rbd_req_read(rq, rbd_dev,
1484                                              cur_snap_id(rbd_dev),
1485                                              ofs,
1486                                              op_size, bio,
1487                                              coll, cur_seg);
1488
1489 next_seg:
1490                         size -= op_size;
1491                         ofs += op_size;
1492
1493                         cur_seg++;
1494                         rq_bio = next_bio;
1495                 } while (size > 0);
1496                 kref_put(&coll->kref, rbd_coll_release);
1497
1498                 if (bp)
1499                         bio_pair_release(bp);
1500                 spin_lock_irq(q->queue_lock);
1501 next:
1502                 rq = blk_fetch_request(q);
1503         }
1504 }
1505
1506 /*
1507  * a queue callback. Makes sure that we don't create a bio that spans across
1508  * multiple osd objects. One exception would be with a single page bios,
1509  * which we handle later at bio_chain_clone
1510  */
1511 static int rbd_merge_bvec(struct request_queue *q, struct bvec_merge_data *bmd,
1512                           struct bio_vec *bvec)
1513 {
1514         struct rbd_device *rbd_dev = q->queuedata;
1515         unsigned int chunk_sectors = 1 << (rbd_dev->header.obj_order - 9);
1516         sector_t sector = bmd->bi_sector + get_start_sect(bmd->bi_bdev);
1517         unsigned int bio_sectors = bmd->bi_size >> 9;
1518         int max;
1519
1520         max =  (chunk_sectors - ((sector & (chunk_sectors - 1))
1521                                  + bio_sectors)) << 9;
1522         if (max < 0)
1523                 max = 0; /* bio_add cannot handle a negative return */
1524         if (max <= bvec->bv_len && bio_sectors == 0)
1525                 return bvec->bv_len;
1526         return max;
1527 }
1528
1529 static void rbd_free_disk(struct rbd_device *rbd_dev)
1530 {
1531         struct gendisk *disk = rbd_dev->disk;
1532
1533         if (!disk)
1534                 return;
1535
1536         rbd_header_free(&rbd_dev->header);
1537
1538         if (disk->flags & GENHD_FL_UP)
1539                 del_gendisk(disk);
1540         if (disk->queue)
1541                 blk_cleanup_queue(disk->queue);
1542         put_disk(disk);
1543 }
1544
1545 /*
1546  * reload the ondisk the header
1547  */
1548 static int rbd_read_header(struct rbd_device *rbd_dev,
1549                            struct rbd_image_header *header)
1550 {
1551         ssize_t rc;
1552         struct rbd_image_header_ondisk *dh;
1553         int snap_count = 0;
1554         u64 snap_names_len = 0;
1555         u64 ver;
1556
1557         while (1) {
1558                 int len = sizeof(*dh) +
1559                           snap_count * sizeof(struct rbd_image_snap_ondisk) +
1560                           snap_names_len;
1561
1562                 rc = -ENOMEM;
1563                 dh = kmalloc(len, GFP_KERNEL);
1564                 if (!dh)
1565                         return -ENOMEM;
1566
1567                 rc = rbd_req_sync_read(rbd_dev,
1568                                        NULL, CEPH_NOSNAP,
1569                                        rbd_dev->obj_md_name,
1570                                        0, len,
1571                                        (char *)dh, &ver);
1572                 if (rc < 0)
1573                         goto out_dh;
1574
1575                 rc = rbd_header_from_disk(header, dh, snap_count, GFP_KERNEL);
1576                 if (rc < 0)
1577                         goto out_dh;
1578
1579                 if (snap_count != header->total_snaps) {
1580                         snap_count = header->total_snaps;
1581                         snap_names_len = header->snap_names_len;
1582                         rbd_header_free(header);
1583                         kfree(dh);
1584                         continue;
1585                 }
1586                 break;
1587         }
1588         header->obj_version = ver;
1589
1590 out_dh:
1591         kfree(dh);
1592         return rc;
1593 }
1594
1595 /*
1596  * create a snapshot
1597  */
1598 static int rbd_header_add_snap(struct rbd_device *dev,
1599                                const char *snap_name,
1600                                gfp_t gfp_flags)
1601 {
1602         int name_len = strlen(snap_name);
1603         u64 new_snapid;
1604         int ret;
1605         void *data, *p, *e;
1606         u64 ver;
1607
1608         /* we should create a snapshot only if we're pointing at the head */
1609         if (dev->cur_snap)
1610                 return -EINVAL;
1611
1612         ret = ceph_monc_create_snapid(&dev->client->monc, dev->poolid,
1613                                       &new_snapid);
1614         dout("created snapid=%lld\n", new_snapid);
1615         if (ret < 0)
1616                 return ret;
1617
1618         data = kmalloc(name_len + 16, gfp_flags);
1619         if (!data)
1620                 return -ENOMEM;
1621
1622         p = data;
1623         e = data + name_len + 16;
1624
1625         ceph_encode_string_safe(&p, e, snap_name, name_len, bad);
1626         ceph_encode_64_safe(&p, e, new_snapid, bad);
1627
1628         ret = rbd_req_sync_exec(dev, dev->obj_md_name, "rbd", "snap_add",
1629                                 data, p - data, &ver);
1630
1631         kfree(data);
1632
1633         if (ret < 0)
1634                 return ret;
1635
1636         dev->header.snapc->seq =  new_snapid;
1637
1638         return 0;
1639 bad:
1640         return -ERANGE;
1641 }
1642
1643 static void __rbd_remove_all_snaps(struct rbd_device *rbd_dev)
1644 {
1645         struct rbd_snap *snap;
1646
1647         while (!list_empty(&rbd_dev->snaps)) {
1648                 snap = list_first_entry(&rbd_dev->snaps, struct rbd_snap, node);
1649                 __rbd_remove_snap_dev(rbd_dev, snap);
1650         }
1651 }
1652
1653 /*
1654  * only read the first part of the ondisk header, without the snaps info
1655  */
1656 static int __rbd_update_snaps(struct rbd_device *rbd_dev)
1657 {
1658         int ret;
1659         struct rbd_image_header h;
1660         u64 snap_seq;
1661         int follow_seq = 0;
1662
1663         ret = rbd_read_header(rbd_dev, &h);
1664         if (ret < 0)
1665                 return ret;
1666
1667         /* resized? */
1668         set_capacity(rbd_dev->disk, h.image_size / 512ULL);
1669
1670         down_write(&rbd_dev->header.snap_rwsem);
1671
1672         snap_seq = rbd_dev->header.snapc->seq;
1673         if (rbd_dev->header.total_snaps &&
1674             rbd_dev->header.snapc->snaps[0] == snap_seq)
1675                 /* pointing at the head, will need to follow that
1676                    if head moves */
1677                 follow_seq = 1;
1678
1679         kfree(rbd_dev->header.snapc);
1680         kfree(rbd_dev->header.snap_names);
1681         kfree(rbd_dev->header.snap_sizes);
1682
1683         rbd_dev->header.total_snaps = h.total_snaps;
1684         rbd_dev->header.snapc = h.snapc;
1685         rbd_dev->header.snap_names = h.snap_names;
1686         rbd_dev->header.snap_names_len = h.snap_names_len;
1687         rbd_dev->header.snap_sizes = h.snap_sizes;
1688         if (follow_seq)
1689                 rbd_dev->header.snapc->seq = rbd_dev->header.snapc->snaps[0];
1690         else
1691                 rbd_dev->header.snapc->seq = snap_seq;
1692
1693         ret = __rbd_init_snaps_header(rbd_dev);
1694
1695         up_write(&rbd_dev->header.snap_rwsem);
1696
1697         return ret;
1698 }
1699
1700 static int rbd_init_disk(struct rbd_device *rbd_dev)
1701 {
1702         struct gendisk *disk;
1703         struct request_queue *q;
1704         int rc;
1705         u64 total_size = 0;
1706
1707         /* contact OSD, request size info about the object being mapped */
1708         rc = rbd_read_header(rbd_dev, &rbd_dev->header);
1709         if (rc)
1710                 return rc;
1711
1712         /* no need to lock here, as rbd_dev is not registered yet */
1713         rc = __rbd_init_snaps_header(rbd_dev);
1714         if (rc)
1715                 return rc;
1716
1717         rc = rbd_header_set_snap(rbd_dev, rbd_dev->snap_name, &total_size);
1718         if (rc)
1719                 return rc;
1720
1721         /* create gendisk info */
1722         rc = -ENOMEM;
1723         disk = alloc_disk(RBD_MINORS_PER_MAJOR);
1724         if (!disk)
1725                 goto out;
1726
1727         snprintf(disk->disk_name, sizeof(disk->disk_name), DRV_NAME "%d",
1728                  rbd_dev->id);
1729         disk->major = rbd_dev->major;
1730         disk->first_minor = 0;
1731         disk->fops = &rbd_bd_ops;
1732         disk->private_data = rbd_dev;
1733
1734         /* init rq */
1735         rc = -ENOMEM;
1736         q = blk_init_queue(rbd_rq_fn, &rbd_dev->lock);
1737         if (!q)
1738                 goto out_disk;
1739         blk_queue_merge_bvec(q, rbd_merge_bvec);
1740         disk->queue = q;
1741
1742         q->queuedata = rbd_dev;
1743
1744         rbd_dev->disk = disk;
1745         rbd_dev->q = q;
1746
1747         /* finally, announce the disk to the world */
1748         set_capacity(disk, total_size / 512ULL);
1749         add_disk(disk);
1750
1751         pr_info("%s: added with size 0x%llx\n",
1752                 disk->disk_name, (unsigned long long)total_size);
1753         return 0;
1754
1755 out_disk:
1756         put_disk(disk);
1757 out:
1758         return rc;
1759 }
1760
1761 /*
1762   sysfs
1763 */
1764
1765 static ssize_t rbd_size_show(struct device *dev,
1766                              struct device_attribute *attr, char *buf)
1767 {
1768         struct rbd_device *rbd_dev = dev_to_rbd(dev);
1769
1770         return sprintf(buf, "%llu\n", (unsigned long long)rbd_dev->header.image_size);
1771 }
1772
1773 static ssize_t rbd_major_show(struct device *dev,
1774                               struct device_attribute *attr, char *buf)
1775 {
1776         struct rbd_device *rbd_dev = dev_to_rbd(dev);
1777
1778         return sprintf(buf, "%d\n", rbd_dev->major);
1779 }
1780
1781 static ssize_t rbd_client_id_show(struct device *dev,
1782                                   struct device_attribute *attr, char *buf)
1783 {
1784         struct rbd_device *rbd_dev = dev_to_rbd(dev);
1785
1786         return sprintf(buf, "client%lld\n", ceph_client_id(rbd_dev->client));
1787 }
1788
1789 static ssize_t rbd_pool_show(struct device *dev,
1790                              struct device_attribute *attr, char *buf)
1791 {
1792         struct rbd_device *rbd_dev = dev_to_rbd(dev);
1793
1794         return sprintf(buf, "%s\n", rbd_dev->pool_name);
1795 }
1796
1797 static ssize_t rbd_name_show(struct device *dev,
1798                              struct device_attribute *attr, char *buf)
1799 {
1800         struct rbd_device *rbd_dev = dev_to_rbd(dev);
1801
1802         return sprintf(buf, "%s\n", rbd_dev->obj);
1803 }
1804
1805 static ssize_t rbd_snap_show(struct device *dev,
1806                              struct device_attribute *attr,
1807                              char *buf)
1808 {
1809         struct rbd_device *rbd_dev = dev_to_rbd(dev);
1810
1811         return sprintf(buf, "%s\n", rbd_dev->snap_name);
1812 }
1813
1814 static ssize_t rbd_image_refresh(struct device *dev,
1815                                  struct device_attribute *attr,
1816                                  const char *buf,
1817                                  size_t size)
1818 {
1819         struct rbd_device *rbd_dev = dev_to_rbd(dev);
1820         int rc;
1821         int ret = size;
1822
1823         mutex_lock_nested(&ctl_mutex, SINGLE_DEPTH_NESTING);
1824
1825         rc = __rbd_update_snaps(rbd_dev);
1826         if (rc < 0)
1827                 ret = rc;
1828
1829         mutex_unlock(&ctl_mutex);
1830         return ret;
1831 }
1832
1833 static DEVICE_ATTR(size, S_IRUGO, rbd_size_show, NULL);
1834 static DEVICE_ATTR(major, S_IRUGO, rbd_major_show, NULL);
1835 static DEVICE_ATTR(client_id, S_IRUGO, rbd_client_id_show, NULL);
1836 static DEVICE_ATTR(pool, S_IRUGO, rbd_pool_show, NULL);
1837 static DEVICE_ATTR(name, S_IRUGO, rbd_name_show, NULL);
1838 static DEVICE_ATTR(refresh, S_IWUSR, NULL, rbd_image_refresh);
1839 static DEVICE_ATTR(current_snap, S_IRUGO, rbd_snap_show, NULL);
1840 static DEVICE_ATTR(create_snap, S_IWUSR, NULL, rbd_snap_add);
1841 static DEVICE_ATTR(rollback_snap, S_IWUSR, NULL, rbd_snap_rollback);
1842
1843 static struct attribute *rbd_attrs[] = {
1844         &dev_attr_size.attr,
1845         &dev_attr_major.attr,
1846         &dev_attr_client_id.attr,
1847         &dev_attr_pool.attr,
1848         &dev_attr_name.attr,
1849         &dev_attr_current_snap.attr,
1850         &dev_attr_refresh.attr,
1851         &dev_attr_create_snap.attr,
1852         &dev_attr_rollback_snap.attr,
1853         NULL
1854 };
1855
1856 static struct attribute_group rbd_attr_group = {
1857         .attrs = rbd_attrs,
1858 };
1859
1860 static const struct attribute_group *rbd_attr_groups[] = {
1861         &rbd_attr_group,
1862         NULL
1863 };
1864
1865 static void rbd_sysfs_dev_release(struct device *dev)
1866 {
1867 }
1868
1869 static struct device_type rbd_device_type = {
1870         .name           = "rbd",
1871         .groups         = rbd_attr_groups,
1872         .release        = rbd_sysfs_dev_release,
1873 };
1874
1875
1876 /*
1877   sysfs - snapshots
1878 */
1879
1880 static ssize_t rbd_snap_size_show(struct device *dev,
1881                                   struct device_attribute *attr,
1882                                   char *buf)
1883 {
1884         struct rbd_snap *snap = container_of(dev, struct rbd_snap, dev);
1885
1886         return sprintf(buf, "%lld\n", (long long)snap->size);
1887 }
1888
1889 static ssize_t rbd_snap_id_show(struct device *dev,
1890                                 struct device_attribute *attr,
1891                                 char *buf)
1892 {
1893         struct rbd_snap *snap = container_of(dev, struct rbd_snap, dev);
1894
1895         return sprintf(buf, "%lld\n", (long long)snap->id);
1896 }
1897
1898 static DEVICE_ATTR(snap_size, S_IRUGO, rbd_snap_size_show, NULL);
1899 static DEVICE_ATTR(snap_id, S_IRUGO, rbd_snap_id_show, NULL);
1900
1901 static struct attribute *rbd_snap_attrs[] = {
1902         &dev_attr_snap_size.attr,
1903         &dev_attr_snap_id.attr,
1904         NULL,
1905 };
1906
1907 static struct attribute_group rbd_snap_attr_group = {
1908         .attrs = rbd_snap_attrs,
1909 };
1910
1911 static void rbd_snap_dev_release(struct device *dev)
1912 {
1913         struct rbd_snap *snap = container_of(dev, struct rbd_snap, dev);
1914         kfree(snap->name);
1915         kfree(snap);
1916 }
1917
1918 static const struct attribute_group *rbd_snap_attr_groups[] = {
1919         &rbd_snap_attr_group,
1920         NULL
1921 };
1922
1923 static struct device_type rbd_snap_device_type = {
1924         .groups         = rbd_snap_attr_groups,
1925         .release        = rbd_snap_dev_release,
1926 };
1927
1928 static void __rbd_remove_snap_dev(struct rbd_device *rbd_dev,
1929                                   struct rbd_snap *snap)
1930 {
1931         list_del(&snap->node);
1932         device_unregister(&snap->dev);
1933 }
1934
1935 static int rbd_register_snap_dev(struct rbd_device *rbd_dev,
1936                                   struct rbd_snap *snap,
1937                                   struct device *parent)
1938 {
1939         struct device *dev = &snap->dev;
1940         int ret;
1941
1942         dev->type = &rbd_snap_device_type;
1943         dev->parent = parent;
1944         dev->release = rbd_snap_dev_release;
1945         dev_set_name(dev, "snap_%s", snap->name);
1946         ret = device_register(dev);
1947
1948         return ret;
1949 }
1950
1951 static int __rbd_add_snap_dev(struct rbd_device *rbd_dev,
1952                               int i, const char *name,
1953                               struct rbd_snap **snapp)
1954 {
1955         int ret;
1956         struct rbd_snap *snap = kzalloc(sizeof(*snap), GFP_KERNEL);
1957         if (!snap)
1958                 return -ENOMEM;
1959         snap->name = kstrdup(name, GFP_KERNEL);
1960         snap->size = rbd_dev->header.snap_sizes[i];
1961         snap->id = rbd_dev->header.snapc->snaps[i];
1962         if (device_is_registered(&rbd_dev->dev)) {
1963                 ret = rbd_register_snap_dev(rbd_dev, snap,
1964                                              &rbd_dev->dev);
1965                 if (ret < 0)
1966                         goto err;
1967         }
1968         *snapp = snap;
1969         return 0;
1970 err:
1971         kfree(snap->name);
1972         kfree(snap);
1973         return ret;
1974 }
1975
1976 /*
1977  * search for the previous snap in a null delimited string list
1978  */
1979 const char *rbd_prev_snap_name(const char *name, const char *start)
1980 {
1981         if (name < start + 2)
1982                 return NULL;
1983
1984         name -= 2;
1985         while (*name) {
1986                 if (name == start)
1987                         return start;
1988                 name--;
1989         }
1990         return name + 1;
1991 }
1992
1993 /*
1994  * compare the old list of snapshots that we have to what's in the header
1995  * and update it accordingly. Note that the header holds the snapshots
1996  * in a reverse order (from newest to oldest) and we need to go from
1997  * older to new so that we don't get a duplicate snap name when
1998  * doing the process (e.g., removed snapshot and recreated a new
1999  * one with the same name.
2000  */
2001 static int __rbd_init_snaps_header(struct rbd_device *rbd_dev)
2002 {
2003         const char *name, *first_name;
2004         int i = rbd_dev->header.total_snaps;
2005         struct rbd_snap *snap, *old_snap = NULL;
2006         int ret;
2007         struct list_head *p, *n;
2008
2009         first_name = rbd_dev->header.snap_names;
2010         name = first_name + rbd_dev->header.snap_names_len;
2011
2012         list_for_each_prev_safe(p, n, &rbd_dev->snaps) {
2013                 u64 cur_id;
2014
2015                 old_snap = list_entry(p, struct rbd_snap, node);
2016
2017                 if (i)
2018                         cur_id = rbd_dev->header.snapc->snaps[i - 1];
2019
2020                 if (!i || old_snap->id < cur_id) {
2021                         /* old_snap->id was skipped, thus was removed */
2022                         __rbd_remove_snap_dev(rbd_dev, old_snap);
2023                         continue;
2024                 }
2025                 if (old_snap->id == cur_id) {
2026                         /* we have this snapshot already */
2027                         i--;
2028                         name = rbd_prev_snap_name(name, first_name);
2029                         continue;
2030                 }
2031                 for (; i > 0;
2032                      i--, name = rbd_prev_snap_name(name, first_name)) {
2033                         if (!name) {
2034                                 WARN_ON(1);
2035                                 return -EINVAL;
2036                         }
2037                         cur_id = rbd_dev->header.snapc->snaps[i];
2038                         /* snapshot removal? handle it above */
2039                         if (cur_id >= old_snap->id)
2040                                 break;
2041                         /* a new snapshot */
2042                         ret = __rbd_add_snap_dev(rbd_dev, i - 1, name, &snap);
2043                         if (ret < 0)
2044                                 return ret;
2045
2046                         /* note that we add it backward so using n and not p */
2047                         list_add(&snap->node, n);
2048                         p = &snap->node;
2049                 }
2050         }
2051         /* we're done going over the old snap list, just add what's left */
2052         for (; i > 0; i--) {
2053                 name = rbd_prev_snap_name(name, first_name);
2054                 if (!name) {
2055                         WARN_ON(1);
2056                         return -EINVAL;
2057                 }
2058                 ret = __rbd_add_snap_dev(rbd_dev, i - 1, name, &snap);
2059                 if (ret < 0)
2060                         return ret;
2061                 list_add(&snap->node, &rbd_dev->snaps);
2062         }
2063
2064         return 0;
2065 }
2066
2067
2068 static void rbd_root_dev_release(struct device *dev)
2069 {
2070 }
2071
2072 static struct device rbd_root_dev = {
2073         .init_name =    "rbd",
2074         .release =      rbd_root_dev_release,
2075 };
2076
2077 static int rbd_bus_add_dev(struct rbd_device *rbd_dev)
2078 {
2079         int ret = -ENOMEM;
2080         struct device *dev;
2081         struct rbd_snap *snap;
2082
2083         mutex_lock_nested(&ctl_mutex, SINGLE_DEPTH_NESTING);
2084         dev = &rbd_dev->dev;
2085
2086         dev->bus = &rbd_bus_type;
2087         dev->type = &rbd_device_type;
2088         dev->parent = &rbd_root_dev;
2089         dev->release = rbd_dev_release;
2090         dev_set_name(dev, "%d", rbd_dev->id);
2091         ret = device_register(dev);
2092         if (ret < 0)
2093                 goto done_free;
2094
2095         list_for_each_entry(snap, &rbd_dev->snaps, node) {
2096                 ret = rbd_register_snap_dev(rbd_dev, snap,
2097                                              &rbd_dev->dev);
2098                 if (ret < 0)
2099                         break;
2100         }
2101
2102         mutex_unlock(&ctl_mutex);
2103         return 0;
2104 done_free:
2105         mutex_unlock(&ctl_mutex);
2106         return ret;
2107 }
2108
2109 static void rbd_bus_del_dev(struct rbd_device *rbd_dev)
2110 {
2111         device_unregister(&rbd_dev->dev);
2112 }
2113
2114 static int rbd_init_watch_dev(struct rbd_device *rbd_dev)
2115 {
2116         int ret, rc;
2117
2118         do {
2119                 ret = rbd_req_sync_watch(rbd_dev, rbd_dev->obj_md_name,
2120                                          rbd_dev->header.obj_version);
2121                 if (ret == -ERANGE) {
2122                         mutex_lock_nested(&ctl_mutex, SINGLE_DEPTH_NESTING);
2123                         rc = __rbd_update_snaps(rbd_dev);
2124                         mutex_unlock(&ctl_mutex);
2125                         if (rc < 0)
2126                                 return rc;
2127                 }
2128         } while (ret == -ERANGE);
2129
2130         return ret;
2131 }
2132
2133 static ssize_t rbd_add(struct bus_type *bus,
2134                        const char *buf,
2135                        size_t count)
2136 {
2137         struct ceph_osd_client *osdc;
2138         struct rbd_device *rbd_dev;
2139         ssize_t rc = -ENOMEM;
2140         int irc, new_id = 0;
2141         struct list_head *tmp;
2142         char *mon_dev_name;
2143         char *options;
2144
2145         if (!try_module_get(THIS_MODULE))
2146                 return -ENODEV;
2147
2148         mon_dev_name = kmalloc(RBD_MAX_OPT_LEN, GFP_KERNEL);
2149         if (!mon_dev_name)
2150                 goto err_out_mod;
2151
2152         options = kmalloc(RBD_MAX_OPT_LEN, GFP_KERNEL);
2153         if (!options)
2154                 goto err_mon_dev;
2155
2156         /* new rbd_device object */
2157         rbd_dev = kzalloc(sizeof(*rbd_dev), GFP_KERNEL);
2158         if (!rbd_dev)
2159                 goto err_out_opt;
2160
2161         /* static rbd_device initialization */
2162         spin_lock_init(&rbd_dev->lock);
2163         INIT_LIST_HEAD(&rbd_dev->node);
2164         INIT_LIST_HEAD(&rbd_dev->snaps);
2165
2166         /* generate unique id: find highest unique id, add one */
2167         mutex_lock_nested(&ctl_mutex, SINGLE_DEPTH_NESTING);
2168
2169         list_for_each(tmp, &rbd_dev_list) {
2170                 struct rbd_device *rbd_dev;
2171
2172                 rbd_dev = list_entry(tmp, struct rbd_device, node);
2173                 if (rbd_dev->id >= new_id)
2174                         new_id = rbd_dev->id + 1;
2175         }
2176
2177         rbd_dev->id = new_id;
2178
2179         /* add to global list */
2180         list_add_tail(&rbd_dev->node, &rbd_dev_list);
2181
2182         /* parse add command */
2183         if (sscanf(buf, "%" __stringify(RBD_MAX_OPT_LEN) "s "
2184                    "%" __stringify(RBD_MAX_OPT_LEN) "s "
2185                    "%" __stringify(RBD_MAX_POOL_NAME_LEN) "s "
2186                    "%" __stringify(RBD_MAX_OBJ_NAME_LEN) "s"
2187                    "%" __stringify(RBD_MAX_SNAP_NAME_LEN) "s",
2188                    mon_dev_name, options, rbd_dev->pool_name,
2189                    rbd_dev->obj, rbd_dev->snap_name) < 4) {
2190                 rc = -EINVAL;
2191                 goto err_out_slot;
2192         }
2193
2194         if (rbd_dev->snap_name[0] == 0)
2195                 rbd_dev->snap_name[0] = '-';
2196
2197         rbd_dev->obj_len = strlen(rbd_dev->obj);
2198         snprintf(rbd_dev->obj_md_name, sizeof(rbd_dev->obj_md_name), "%s%s",
2199                  rbd_dev->obj, RBD_SUFFIX);
2200
2201         /* initialize rest of new object */
2202         snprintf(rbd_dev->name, DEV_NAME_LEN, DRV_NAME "%d", rbd_dev->id);
2203         rc = rbd_get_client(rbd_dev, mon_dev_name, options);
2204         if (rc < 0)
2205                 goto err_out_slot;
2206
2207         mutex_unlock(&ctl_mutex);
2208
2209         /* pick the pool */
2210         osdc = &rbd_dev->client->osdc;
2211         rc = ceph_pg_poolid_by_name(osdc->osdmap, rbd_dev->pool_name);
2212         if (rc < 0)
2213                 goto err_out_client;
2214         rbd_dev->poolid = rc;
2215
2216         /* register our block device */
2217         irc = register_blkdev(0, rbd_dev->name);
2218         if (irc < 0) {
2219                 rc = irc;
2220                 goto err_out_client;
2221         }
2222         rbd_dev->major = irc;
2223
2224         rc = rbd_bus_add_dev(rbd_dev);
2225         if (rc)
2226                 goto err_out_blkdev;
2227
2228         /* set up and announce blkdev mapping */
2229         rc = rbd_init_disk(rbd_dev);
2230         if (rc)
2231                 goto err_out_bus;
2232
2233         rc = rbd_init_watch_dev(rbd_dev);
2234         if (rc)
2235                 goto err_out_bus;
2236
2237         return count;
2238
2239 err_out_bus:
2240         mutex_lock_nested(&ctl_mutex, SINGLE_DEPTH_NESTING);
2241         list_del_init(&rbd_dev->node);
2242         mutex_unlock(&ctl_mutex);
2243
2244         /* this will also clean up rest of rbd_dev stuff */
2245
2246         rbd_bus_del_dev(rbd_dev);
2247         kfree(options);
2248         kfree(mon_dev_name);
2249         return rc;
2250
2251 err_out_blkdev:
2252         unregister_blkdev(rbd_dev->major, rbd_dev->name);
2253 err_out_client:
2254         rbd_put_client(rbd_dev);
2255         mutex_lock_nested(&ctl_mutex, SINGLE_DEPTH_NESTING);
2256 err_out_slot:
2257         list_del_init(&rbd_dev->node);
2258         mutex_unlock(&ctl_mutex);
2259
2260         kfree(rbd_dev);
2261 err_out_opt:
2262         kfree(options);
2263 err_mon_dev:
2264         kfree(mon_dev_name);
2265 err_out_mod:
2266         dout("Error adding device %s\n", buf);
2267         module_put(THIS_MODULE);
2268         return rc;
2269 }
2270
2271 static struct rbd_device *__rbd_get_dev(unsigned long id)
2272 {
2273         struct list_head *tmp;
2274         struct rbd_device *rbd_dev;
2275
2276         list_for_each(tmp, &rbd_dev_list) {
2277                 rbd_dev = list_entry(tmp, struct rbd_device, node);
2278                 if (rbd_dev->id == id)
2279                         return rbd_dev;
2280         }
2281         return NULL;
2282 }
2283
2284 static void rbd_dev_release(struct device *dev)
2285 {
2286         struct rbd_device *rbd_dev =
2287                         container_of(dev, struct rbd_device, dev);
2288
2289         if (rbd_dev->watch_request)
2290                 ceph_osdc_unregister_linger_request(&rbd_dev->client->osdc,
2291                                                     rbd_dev->watch_request);
2292         if (rbd_dev->watch_event)
2293                 ceph_osdc_cancel_event(rbd_dev->watch_event);
2294
2295         rbd_put_client(rbd_dev);
2296
2297         /* clean up and free blkdev */
2298         rbd_free_disk(rbd_dev);
2299         unregister_blkdev(rbd_dev->major, rbd_dev->name);
2300         kfree(rbd_dev);
2301
2302         /* release module ref */
2303         module_put(THIS_MODULE);
2304 }
2305
2306 static ssize_t rbd_remove(struct bus_type *bus,
2307                           const char *buf,
2308                           size_t count)
2309 {
2310         struct rbd_device *rbd_dev = NULL;
2311         int target_id, rc;
2312         unsigned long ul;
2313         int ret = count;
2314
2315         rc = strict_strtoul(buf, 10, &ul);
2316         if (rc)
2317                 return rc;
2318
2319         /* convert to int; abort if we lost anything in the conversion */
2320         target_id = (int) ul;
2321         if (target_id != ul)
2322                 return -EINVAL;
2323
2324         mutex_lock_nested(&ctl_mutex, SINGLE_DEPTH_NESTING);
2325
2326         rbd_dev = __rbd_get_dev(target_id);
2327         if (!rbd_dev) {
2328                 ret = -ENOENT;
2329                 goto done;
2330         }
2331
2332         list_del_init(&rbd_dev->node);
2333
2334         __rbd_remove_all_snaps(rbd_dev);
2335         rbd_bus_del_dev(rbd_dev);
2336
2337 done:
2338         mutex_unlock(&ctl_mutex);
2339         return ret;
2340 }
2341
2342 static ssize_t rbd_snap_add(struct device *dev,
2343                             struct device_attribute *attr,
2344                             const char *buf,
2345                             size_t count)
2346 {
2347         struct rbd_device *rbd_dev = dev_to_rbd(dev);
2348         int ret;
2349         char *name = kmalloc(count + 1, GFP_KERNEL);
2350         if (!name)
2351                 return -ENOMEM;
2352
2353         snprintf(name, count, "%s", buf);
2354
2355         mutex_lock_nested(&ctl_mutex, SINGLE_DEPTH_NESTING);
2356
2357         ret = rbd_header_add_snap(rbd_dev,
2358                                   name, GFP_KERNEL);
2359         if (ret < 0)
2360                 goto err_unlock;
2361
2362         ret = __rbd_update_snaps(rbd_dev);
2363         if (ret < 0)
2364                 goto err_unlock;
2365
2366         /* shouldn't hold ctl_mutex when notifying.. notify might
2367            trigger a watch callback that would need to get that mutex */
2368         mutex_unlock(&ctl_mutex);
2369
2370         /* make a best effort, don't error if failed */
2371         rbd_req_sync_notify(rbd_dev, rbd_dev->obj_md_name);
2372
2373         ret = count;
2374         kfree(name);
2375         return ret;
2376
2377 err_unlock:
2378         mutex_unlock(&ctl_mutex);
2379         kfree(name);
2380         return ret;
2381 }
2382
2383 static ssize_t rbd_snap_rollback(struct device *dev,
2384                                  struct device_attribute *attr,
2385                                  const char *buf,
2386                                  size_t count)
2387 {
2388         struct rbd_device *rbd_dev = dev_to_rbd(dev);
2389         int ret;
2390         u64 snapid;
2391         u64 cur_ofs;
2392         char *seg_name = NULL;
2393         char *snap_name = kmalloc(count + 1, GFP_KERNEL);
2394         ret = -ENOMEM;
2395         if (!snap_name)
2396                 return ret;
2397
2398         /* parse snaps add command */
2399         snprintf(snap_name, count, "%s", buf);
2400         seg_name = kmalloc(RBD_MAX_SEG_NAME_LEN + 1, GFP_NOIO);
2401         if (!seg_name)
2402                 goto done;
2403
2404         mutex_lock_nested(&ctl_mutex, SINGLE_DEPTH_NESTING);
2405
2406         ret = snap_by_name(&rbd_dev->header, snap_name, &snapid, NULL);
2407         if (ret < 0)
2408                 goto done_unlock;
2409
2410         dout("snapid=%lld\n", snapid);
2411
2412         cur_ofs = 0;
2413         while (cur_ofs < rbd_dev->header.image_size) {
2414                 cur_ofs += rbd_get_segment(&rbd_dev->header,
2415                                            rbd_dev->obj,
2416                                            cur_ofs, (u64)-1,
2417                                            seg_name, NULL);
2418                 dout("seg_name=%s\n", seg_name);
2419
2420                 ret = rbd_req_sync_rollback_obj(rbd_dev, snapid, seg_name);
2421                 if (ret < 0)
2422                         pr_warning("could not roll back obj %s err=%d\n",
2423                                    seg_name, ret);
2424         }
2425
2426         ret = __rbd_update_snaps(rbd_dev);
2427         if (ret < 0)
2428                 goto done_unlock;
2429
2430         ret = count;
2431
2432 done_unlock:
2433         mutex_unlock(&ctl_mutex);
2434 done:
2435         kfree(seg_name);
2436         kfree(snap_name);
2437
2438         return ret;
2439 }
2440
2441 static struct bus_attribute rbd_bus_attrs[] = {
2442         __ATTR(add, S_IWUSR, NULL, rbd_add),
2443         __ATTR(remove, S_IWUSR, NULL, rbd_remove),
2444         __ATTR_NULL
2445 };
2446
2447 /*
2448  * create control files in sysfs
2449  * /sys/bus/rbd/...
2450  */
2451 static int rbd_sysfs_init(void)
2452 {
2453         int ret;
2454
2455         rbd_bus_type.bus_attrs = rbd_bus_attrs;
2456
2457         ret = bus_register(&rbd_bus_type);
2458          if (ret < 0)
2459                 return ret;
2460
2461         ret = device_register(&rbd_root_dev);
2462
2463         return ret;
2464 }
2465
2466 static void rbd_sysfs_cleanup(void)
2467 {
2468         device_unregister(&rbd_root_dev);
2469         bus_unregister(&rbd_bus_type);
2470 }
2471
2472 int __init rbd_init(void)
2473 {
2474         int rc;
2475
2476         rc = rbd_sysfs_init();
2477         if (rc)
2478                 return rc;
2479         spin_lock_init(&node_lock);
2480         pr_info("loaded " DRV_NAME_LONG "\n");
2481         return 0;
2482 }
2483
2484 void __exit rbd_exit(void)
2485 {
2486         rbd_sysfs_cleanup();
2487 }
2488
2489 module_init(rbd_init);
2490 module_exit(rbd_exit);
2491
2492 MODULE_AUTHOR("Sage Weil <sage@newdream.net>");
2493 MODULE_AUTHOR("Yehuda Sadeh <yehuda@hq.newdream.net>");
2494 MODULE_DESCRIPTION("rados block device");
2495
2496 /* following authorship retained from original osdblk.c */
2497 MODULE_AUTHOR("Jeff Garzik <jeff@garzik.org>");
2498
2499 MODULE_LICENSE("GPL");