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