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/buffer_head.h>
  21 #include <linux/blkdev.h>
  22 #include <linux/random.h>
  23 #include <linux/iocontext.h>
  24 #include <asm/div64.h>
  25 #include "compat.h"
  26 #include "ctree.h"
  27 #include "extent_map.h"
  28 #include "disk-io.h"
  29 #include "transaction.h"
  30 #include "print-tree.h"
  31 #include "volumes.h"
  32 #include "async-thread.h"
  33
  34 struct map_lookup {
  35         u64 type;
  36         int io_align;
  37         int io_width;
  38         int stripe_len;
  39         int sector_size;
  40         int num_stripes;
  41         int sub_stripes;
  42         struct btrfs_bio_stripe stripes[];
  43 };
  44
  45 static int init_first_rw_device(struct btrfs_trans_handle *trans,
  46                                 struct btrfs_root *root,
  47                                 struct btrfs_device *device);
  48 static int btrfs_relocate_sys_chunks(struct btrfs_root *root);
  49
  50 #define map_lookup_size(n) (sizeof(struct map_lookup) + \
  51                             (sizeof(struct btrfs_bio_stripe) * (n)))
  52
  53 static DEFINE_MUTEX(uuid_mutex);
  54 static LIST_HEAD(fs_uuids);
  55
  56 void btrfs_lock_volumes(void)
  57 {
  58         mutex_lock(&uuid_mutex);
  59 }
  60
  61 void btrfs_unlock_volumes(void)
  62 {
  63         mutex_unlock(&uuid_mutex);
  64 }
  65
  66 static void lock_chunks(struct btrfs_root *root)
  67 {
  68         mutex_lock(&root->fs_info->chunk_mutex);
  69 }
  70
  71 static void unlock_chunks(struct btrfs_root *root)
  72 {
  73         mutex_unlock(&root->fs_info->chunk_mutex);
  74 }
  75
  76 static void free_fs_devices(struct btrfs_fs_devices *fs_devices)
  77 {
  78         struct btrfs_device *device;
  79         WARN_ON(fs_devices->opened);
  80         while (!list_empty(&fs_devices->devices)) {
  81                 device = list_entry(fs_devices->devices.next,
  82                                     struct btrfs_device, dev_list);
  83                 list_del(&device->dev_list);
  84                 kfree(device->name);
  85                 kfree(device);
  86         }
  87         kfree(fs_devices);
  88 }
  89
  90 int btrfs_cleanup_fs_uuids(void)
  91 {
  92         struct btrfs_fs_devices *fs_devices;
  93
  94         while (!list_empty(&fs_uuids)) {
  95                 fs_devices = list_entry(fs_uuids.next,
  96                                         struct btrfs_fs_devices, list);
  97                 list_del(&fs_devices->list);
  98                 free_fs_devices(fs_devices);
  99         }
 100         return 0;
 101 }
 102
 103 static noinline struct btrfs_device *__find_device(struct list_head *head,
 104                                                    u64 devid, u8 *uuid)
 105 {
 106         struct btrfs_device *dev;
 107
 108         list_for_each_entry(dev, head, dev_list) {
 109                 if (dev->devid == devid &&
 110                     (!uuid || !memcmp(dev->uuid, uuid, BTRFS_UUID_SIZE))) {
 111                         return dev;
 112                 }
 113         }
 114         return NULL;
 115 }
 116
 117 static noinline struct btrfs_fs_devices *find_fsid(u8 *fsid)
 118 {
 119         struct btrfs_fs_devices *fs_devices;
 120
 121         list_for_each_entry(fs_devices, &fs_uuids, list) {
 122                 if (memcmp(fsid, fs_devices->fsid, BTRFS_FSID_SIZE) == 0)
 123                         return fs_devices;
 124         }
 125         return NULL;
 126 }
 127
 128 static void requeue_list(struct btrfs_pending_bios *pending_bios,
 129                         struct bio *head, struct bio *tail)
 130 {
 131
 132         struct bio *old_head;
 133
 134         old_head = pending_bios->head;
 135         pending_bios->head = head;
 136         if (pending_bios->tail)
 137                 tail->bi_next = old_head;
 138         else
 139                 pending_bios->tail = tail;
 140 }
 141
 142 /*
 143  * we try to collect pending bios for a device so we don't get a large
 144  * number of procs sending bios down to the same device.  This greatly
 145  * improves the schedulers ability to collect and merge the bios.
 146  *
 147  * But, it also turns into a long list of bios to process and that is sure
 148  * to eventually make the worker thread block.  The solution here is to
 149  * make some progress and then put this work struct back at the end of
 150  * the list if the block device is congested.  This way, multiple devices
 151  * can make progress from a single worker thread.
 152  */
 153 static noinline int run_scheduled_bios(struct btrfs_device *device)
 154 {
 155         struct bio *pending;
 156         struct backing_dev_info *bdi;
 157         struct btrfs_fs_info *fs_info;
 158         struct btrfs_pending_bios *pending_bios;
 159         struct bio *tail;
 160         struct bio *cur;
 161         int again = 0;
 162         unsigned long num_run;
 163         unsigned long num_sync_run;
 164         unsigned long batch_run = 0;
 165         unsigned long limit;
 166         unsigned long last_waited = 0;
 167         int force_reg = 0;
 168
 169         bdi = blk_get_backing_dev_info(device->bdev);
 170         fs_info = device->dev_root->fs_info;
 171         limit = btrfs_async_submit_limit(fs_info);
 172         limit = limit * 2 / 3;
 173
 174         /* we want to make sure that every time we switch from the sync
 175          * list to the normal list, we unplug
 176          */
 177         num_sync_run = 0;
 178
 179 loop:
 180         spin_lock(&device->io_lock);
 181
 182 loop_lock:
 183         num_run = 0;
 184
 185         /* take all the bios off the list at once and process them
 186          * later on (without the lock held).  But, remember the
 187          * tail and other pointers so the bios can be properly reinserted
 188          * into the list if we hit congestion
 189          */
 190         if (!force_reg && device->pending_sync_bios.head) {
 191                 pending_bios = &device->pending_sync_bios;
 192                 force_reg = 1;
 193         } else {
 194                 pending_bios = &device->pending_bios;
 195                 force_reg = 0;
 196         }
 197
 198         pending = pending_bios->head;
 199         tail = pending_bios->tail;
 200         WARN_ON(pending && !tail);
 201
 202         /*
 203          * if pending was null this time around, no bios need processing
 204          * at all and we can stop.  Otherwise it'll loop back up again
 205          * and do an additional check so no bios are missed.
 206          *
 207          * device->running_pending is used to synchronize with the
 208          * schedule_bio code.
 209          */
 210         if (device->pending_sync_bios.head == NULL &&
 211             device->pending_bios.head == NULL) {
 212                 again = 0;
 213                 device->running_pending = 0;
 214         } else {
 215                 again = 1;
 216                 device->running_pending = 1;
 217         }
 218
 219         pending_bios->head = NULL;
 220         pending_bios->tail = NULL;
 221
 222         spin_unlock(&device->io_lock);
 223
 224         /*
 225          * if we're doing the regular priority list, make sure we unplug
 226          * for any high prio bios we've sent down
 227          */
 228         if (pending_bios == &device->pending_bios && num_sync_run > 0) {
 229                 num_sync_run = 0;
 230                 blk_run_backing_dev(bdi, NULL);
 231         }
 232
 233         while (pending) {
 234
 235                 rmb();
 236                 /* we want to work on both lists, but do more bios on the
 237                  * sync list than the regular list
 238                  */
 239                 if ((num_run > 32 &&
 240                     pending_bios != &device->pending_sync_bios &&
 241                     device->pending_sync_bios.head) ||
 242                    (num_run > 64 && pending_bios == &device->pending_sync_bios &&
 243                     device->pending_bios.head)) {
 244                         spin_lock(&device->io_lock);
 245                         requeue_list(pending_bios, pending, tail);
 246                         goto loop_lock;
 247                 }
 248
 249                 cur = pending;
 250                 pending = pending->bi_next;
 251                 cur->bi_next = NULL;
 252                 atomic_dec(&fs_info->nr_async_bios);
 253
 254                 if (atomic_read(&fs_info->nr_async_bios) < limit &&
 255                     waitqueue_active(&fs_info->async_submit_wait))
 256                         wake_up(&fs_info->async_submit_wait);
 257
 258                 BUG_ON(atomic_read(&cur->bi_cnt) == 0);
 259
 260                 if (bio_rw_flagged(cur, BIO_RW_SYNCIO))
 261                         num_sync_run++;
 262
 263                 submit_bio(cur->bi_rw, cur);
 264                 num_run++;
 265                 batch_run++;
 266                 if (need_resched()) {
 267                         if (num_sync_run) {
 268                                 blk_run_backing_dev(bdi, NULL);
 269                                 num_sync_run = 0;
 270                         }
 271                         cond_resched();
 272                 }
 273
 274                 /*
 275                  * we made progress, there is more work to do and the bdi
 276                  * is now congested.  Back off and let other work structs
 277                  * run instead
 278                  */
 279                 if (pending && bdi_write_congested(bdi) && batch_run > 8 &&
 280                     fs_info->fs_devices->open_devices > 1) {
 281                         struct io_context *ioc;
 282
 283                         ioc = current->io_context;
 284
 285                         /*
 286                          * the main goal here is that we don't want to
 287                          * block if we're going to be able to submit
 288                          * more requests without blocking.
 289                          *
 290                          * This code does two great things, it pokes into
 291                          * the elevator code from a filesystem _and_
 292                          * it makes assumptions about how batching works.
 293                          */
 294                         if (ioc && ioc->nr_batch_requests > 0 &&
 295                             time_before(jiffies, ioc->last_waited + HZ/50UL) &&
 296                             (last_waited == 0 ||
 297                              ioc->last_waited == last_waited)) {
 298                                 /*
 299                                  * we want to go through our batch of
 300                                  * requests and stop.  So, we copy out
 301                                  * the ioc->last_waited time and test
 302                                  * against it before looping
 303                                  */
 304                                 last_waited = ioc->last_waited;
 305                                 if (need_resched()) {
 306                                         if (num_sync_run) {
 307                                                 blk_run_backing_dev(bdi, NULL);
 308                                                 num_sync_run = 0;
 309                                         }
 310                                         cond_resched();
 311                                 }
 312                                 continue;
 313                         }
 314                         spin_lock(&device->io_lock);
 315                         requeue_list(pending_bios, pending, tail);
 316                         device->running_pending = 1;
 317
 318                         spin_unlock(&device->io_lock);
 319                         btrfs_requeue_work(&device->work);
 320                         goto done;
 321                 }
 322         }
 323
 324         if (num_sync_run) {
 325                 num_sync_run = 0;
 326                 blk_run_backing_dev(bdi, NULL);
 327         }
 328         /*
 329          * IO has already been through a long path to get here.  Checksumming,
 330          * async helper threads, perhaps compression.  We've done a pretty
 331          * good job of collecting a batch of IO and should just unplug
 332          * the device right away.
 333          *
 334          * This will help anyone who is waiting on the IO, they might have
 335          * already unplugged, but managed to do so before the bio they
 336          * cared about found its way down here.
 337          */
 338         blk_run_backing_dev(bdi, NULL);
 339
 340         cond_resched();
 341         if (again)
 342                 goto loop;
 343
 344         spin_lock(&device->io_lock);
 345         if (device->pending_bios.head || device->pending_sync_bios.head)
 346                 goto loop_lock;
 347         spin_unlock(&device->io_lock);
 348
 349 done:
 350         return 0;
 351 }
 352
 353 static void pending_bios_fn(struct btrfs_work *work)
 354 {
 355         struct btrfs_device *device;
 356
 357         device = container_of(work, struct btrfs_device, work);
 358         run_scheduled_bios(device);
 359 }
 360
 361 static noinline int device_list_add(const char *path,
 362                            struct btrfs_super_block *disk_super,
 363                            u64 devid, struct btrfs_fs_devices **fs_devices_ret)
 364 {
 365         struct btrfs_device *device;
 366         struct btrfs_fs_devices *fs_devices;
 367         u64 found_transid = btrfs_super_generation(disk_super);
 368         char *name;
 369
 370         fs_devices = find_fsid(disk_super->fsid);
 371         if (!fs_devices) {
 372                 fs_devices = kzalloc(sizeof(*fs_devices), GFP_NOFS);
 373                 if (!fs_devices)
 374                         return -ENOMEM;
 375                 INIT_LIST_HEAD(&fs_devices->devices);
 376                 INIT_LIST_HEAD(&fs_devices->alloc_list);
 377                 list_add(&fs_devices->list, &fs_uuids);
 378                 memcpy(fs_devices->fsid, disk_super->fsid, BTRFS_FSID_SIZE);
 379                 fs_devices->latest_devid = devid;
 380                 fs_devices->latest_trans = found_transid;
 381                 mutex_init(&fs_devices->device_list_mutex);
 382                 device = NULL;
 383         } else {
 384                 device = __find_device(&fs_devices->devices, devid,
 385                                        disk_super->dev_item.uuid);
 386         }
 387         if (!device) {
 388                 if (fs_devices->opened)
 389                         return -EBUSY;
 390
 391                 device = kzalloc(sizeof(*device), GFP_NOFS);
 392                 if (!device) {
 393                         /* we can safely leave the fs_devices entry around */
 394                         return -ENOMEM;
 395                 }
 396                 device->devid = devid;
 397                 device->work.func = pending_bios_fn;
 398                 memcpy(device->uuid, disk_super->dev_item.uuid,
 399                        BTRFS_UUID_SIZE);
 400                 device->barriers = 1;
 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                 device->barriers = 1;
 465                 spin_lock_init(&device->io_lock);
 466                 INIT_LIST_HEAD(&device->dev_list);
 467                 INIT_LIST_HEAD(&device->dev_alloc_list);
 468
 469                 list_add(&device->dev_list, &fs_devices->devices);
 470                 device->fs_devices = fs_devices;
 471                 fs_devices->num_devices++;
 472         }
 473         mutex_unlock(&orig->device_list_mutex);
 474         return fs_devices;
 475 error:
 476         mutex_unlock(&orig->device_list_mutex);
 477         free_fs_devices(fs_devices);
 478         return ERR_PTR(-ENOMEM);
 479 }
 480
 481 int btrfs_close_extra_devices(struct btrfs_fs_devices *fs_devices)
 482 {
 483         struct btrfs_device *device, *next;
 484
 485         mutex_lock(&uuid_mutex);
 486 again:
 487         mutex_lock(&fs_devices->device_list_mutex);
 488         list_for_each_entry_safe(device, next, &fs_devices->devices, dev_list) {
 489                 if (device->in_fs_metadata)
 490                         continue;
 491
 492                 if (device->bdev) {
 493                         close_bdev_exclusive(device->bdev, device->mode);
 494                         device->bdev = NULL;
 495                         fs_devices->open_devices--;
 496                 }
 497                 if (device->writeable) {
 498                         list_del_init(&device->dev_alloc_list);
 499                         device->writeable = 0;
 500                         fs_devices->rw_devices--;
 501                 }
 502                 list_del_init(&device->dev_list);
 503                 fs_devices->num_devices--;
 504                 kfree(device->name);
 505                 kfree(device);
 506         }
 507         mutex_unlock(&fs_devices->device_list_mutex);
 508
 509         if (fs_devices->seed) {
 510                 fs_devices = fs_devices->seed;
 511                 goto again;
 512         }
 513
 514         mutex_unlock(&uuid_mutex);
 515         return 0;
 516 }
 517
 518 static int __btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
 519 {
 520         struct btrfs_device *device;
 521
 522         if (--fs_devices->opened > 0)
 523                 return 0;
 524
 525         list_for_each_entry(device, &fs_devices->devices, dev_list) {
 526                 if (device->bdev) {
 527                         close_bdev_exclusive(device->bdev, device->mode);
 528                         fs_devices->open_devices--;
 529                 }
 530                 if (device->writeable) {
 531                         list_del_init(&device->dev_alloc_list);
 532                         fs_devices->rw_devices--;
 533                 }
 534
 535                 device->bdev = NULL;
 536                 device->writeable = 0;
 537                 device->in_fs_metadata = 0;
 538         }
 539         WARN_ON(fs_devices->open_devices);
 540         WARN_ON(fs_devices->rw_devices);
 541         fs_devices->opened = 0;
 542         fs_devices->seeding = 0;
 543
 544         return 0;
 545 }
 546
 547 int btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
 548 {
 549         struct btrfs_fs_devices *seed_devices = NULL;
 550         int ret;
 551
 552         mutex_lock(&uuid_mutex);
 553         ret = __btrfs_close_devices(fs_devices);
 554         if (!fs_devices->opened) {
 555                 seed_devices = fs_devices->seed;
 556                 fs_devices->seed = NULL;
 557         }
 558         mutex_unlock(&uuid_mutex);
 559
 560         while (seed_devices) {
 561                 fs_devices = seed_devices;
 562                 seed_devices = fs_devices->seed;
 563                 __btrfs_close_devices(fs_devices);
 564                 free_fs_devices(fs_devices);
 565         }
 566         return ret;
 567 }
 568
 569 static int __btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
 570                                 fmode_t flags, void *holder)
 571 {
 572         struct block_device *bdev;
 573         struct list_head *head = &fs_devices->devices;
 574         struct btrfs_device *device;
 575         struct block_device *latest_bdev = NULL;
 576         struct buffer_head *bh;
 577         struct btrfs_super_block *disk_super;
 578         u64 latest_devid = 0;
 579         u64 latest_transid = 0;
 580         u64 devid;
 581         int seeding = 1;
 582         int ret = 0;
 583
 584         list_for_each_entry(device, head, dev_list) {
 585                 if (device->bdev)
 586                         continue;
 587                 if (!device->name)
 588                         continue;
 589
 590                 bdev = open_bdev_exclusive(device->name, flags, holder);
 591                 if (IS_ERR(bdev)) {
 592                         printk(KERN_INFO "open %s failed\n", device->name);
 593                         goto error;
 594                 }
 595                 set_blocksize(bdev, 4096);
 596
 597                 bh = btrfs_read_dev_super(bdev);
 598                 if (!bh)
 599                         goto error_close;
 600
 601                 disk_super = (struct btrfs_super_block *)bh->b_data;
 602                 devid = btrfs_stack_device_id(&disk_super->dev_item);
 603                 if (devid != device->devid)
 604                         goto error_brelse;
 605
 606                 if (memcmp(device->uuid, disk_super->dev_item.uuid,
 607                            BTRFS_UUID_SIZE))
 608                         goto error_brelse;
 609
 610                 device->generation = btrfs_super_generation(disk_super);
 611                 if (!latest_transid || device->generation > latest_transid) {
 612                         latest_devid = devid;
 613                         latest_transid = device->generation;
 614                         latest_bdev = bdev;
 615                 }
 616
 617                 if (btrfs_super_flags(disk_super) & BTRFS_SUPER_FLAG_SEEDING) {
 618                         device->writeable = 0;
 619                 } else {
 620                         device->writeable = !bdev_read_only(bdev);
 621                         seeding = 0;
 622                 }
 623
 624                 device->bdev = bdev;
 625                 device->in_fs_metadata = 0;
 626                 device->mode = flags;
 627
 628                 if (!blk_queue_nonrot(bdev_get_queue(bdev)))
 629                         fs_devices->rotating = 1;
 630
 631                 fs_devices->open_devices++;
 632                 if (device->writeable) {
 633                         fs_devices->rw_devices++;
 634                         list_add(&device->dev_alloc_list,
 635                                  &fs_devices->alloc_list);
 636                 }
 637                 continue;
 638
 639 error_brelse:
 640                 brelse(bh);
 641 error_close:
 642                 close_bdev_exclusive(bdev, FMODE_READ);
 643 error:
 644                 continue;
 645         }
 646         if (fs_devices->open_devices == 0) {
 647                 ret = -EIO;
 648                 goto out;
 649         }
 650         fs_devices->seeding = seeding;
 651         fs_devices->opened = 1;
 652         fs_devices->latest_bdev = latest_bdev;
 653         fs_devices->latest_devid = latest_devid;
 654         fs_devices->latest_trans = latest_transid;
 655         fs_devices->total_rw_bytes = 0;
 656 out:
 657         return ret;
 658 }
 659
 660 int btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
 661                        fmode_t flags, void *holder)
 662 {
 663         int ret;
 664
 665         mutex_lock(&uuid_mutex);
 666         if (fs_devices->opened) {
 667                 fs_devices->opened++;
 668                 ret = 0;
 669         } else {
 670                 ret = __btrfs_open_devices(fs_devices, flags, holder);
 671         }
 672         mutex_unlock(&uuid_mutex);
 673         return ret;
 674 }
 675
 676 int btrfs_scan_one_device(const char *path, fmode_t flags, void *holder,
 677                           struct btrfs_fs_devices **fs_devices_ret)
 678 {
 679         struct btrfs_super_block *disk_super;
 680         struct block_device *bdev;
 681         struct buffer_head *bh;
 682         int ret;
 683         u64 devid;
 684         u64 transid;
 685
 686         mutex_lock(&uuid_mutex);
 687
 688         bdev = open_bdev_exclusive(path, flags, holder);
 689
 690         if (IS_ERR(bdev)) {
 691                 ret = PTR_ERR(bdev);
 692                 goto error;
 693         }
 694
 695         ret = set_blocksize(bdev, 4096);
 696         if (ret)
 697                 goto error_close;
 698         bh = btrfs_read_dev_super(bdev);
 699         if (!bh) {
 700                 ret = -EIO;
 701                 goto error_close;
 702         }
 703         disk_super = (struct btrfs_super_block *)bh->b_data;
 704         devid = btrfs_stack_device_id(&disk_super->dev_item);
 705         transid = btrfs_super_generation(disk_super);
 706         if (disk_super->label[0])
 707                 printk(KERN_INFO "device label %s ", disk_super->label);
 708         else {
 709                 /* FIXME, make a readl uuid parser */
 710                 printk(KERN_INFO "device fsid %llx-%llx ",
 711                        *(unsigned long long *)disk_super->fsid,
 712                        *(unsigned long long *)(disk_super->fsid + 8));
 713         }
 714         printk(KERN_CONT "devid %llu transid %llu %s\n",
 715                (unsigned long long)devid, (unsigned long long)transid, path);
 716         ret = device_list_add(path, disk_super, devid, fs_devices_ret);
 717
 718         brelse(bh);
 719 error_close:
 720         close_bdev_exclusive(bdev, flags);
 721 error:
 722         mutex_unlock(&uuid_mutex);
 723         return ret;
 724 }
 725
 726 /*
 727  * this uses a pretty simple search, the expectation is that it is
 728  * called very infrequently and that a given device has a small number
 729  * of extents
 730  */
 731 int find_free_dev_extent(struct btrfs_trans_handle *trans,
 732                          struct btrfs_device *device, u64 num_bytes,
 733                          u64 *start, u64 *max_avail)
 734 {
 735         struct btrfs_key key;
 736         struct btrfs_root *root = device->dev_root;
 737         struct btrfs_dev_extent *dev_extent = NULL;
 738         struct btrfs_path *path;
 739         u64 hole_size = 0;
 740         u64 last_byte = 0;
 741         u64 search_start = 0;
 742         u64 search_end = device->total_bytes;
 743         int ret;
 744         int slot = 0;
 745         int start_found;
 746         struct extent_buffer *l;
 747
 748         path = btrfs_alloc_path();
 749         if (!path)
 750                 return -ENOMEM;
 751         path->reada = 2;
 752         start_found = 0;
 753
 754         /* FIXME use last free of some kind */
 755
 756         /* we don't want to overwrite the superblock on the drive,
 757          * so we make sure to start at an offset of at least 1MB
 758          */
 759         search_start = max((u64)1024 * 1024, search_start);
 760
 761         if (root->fs_info->alloc_start + num_bytes <= device->total_bytes)
 762                 search_start = max(root->fs_info->alloc_start, search_start);
 763
 764         key.objectid = device->devid;
 765         key.offset = search_start;
 766         key.type = BTRFS_DEV_EXTENT_KEY;
 767         ret = btrfs_search_slot(trans, root, &key, path, 0, 0);
 768         if (ret < 0)
 769                 goto error;
 770         if (ret > 0) {
 771                 ret = btrfs_previous_item(root, path, key.objectid, key.type);
 772                 if (ret < 0)
 773                         goto error;
 774                 if (ret > 0)
 775                         start_found = 1;
 776         }
 777         l = path->nodes[0];
 778         btrfs_item_key_to_cpu(l, &key, path->slots[0]);
 779         while (1) {
 780                 l = path->nodes[0];
 781                 slot = path->slots[0];
 782                 if (slot >= btrfs_header_nritems(l)) {
 783                         ret = btrfs_next_leaf(root, path);
 784                         if (ret == 0)
 785                                 continue;
 786                         if (ret < 0)
 787                                 goto error;
 788 no_more_items:
 789                         if (!start_found) {
 790                                 if (search_start >= search_end) {
 791                                         ret = -ENOSPC;
 792                                         goto error;
 793                                 }
 794                                 *start = search_start;
 795                                 start_found = 1;
 796                                 goto check_pending;
 797                         }
 798                         *start = last_byte > search_start ?
 799                                 last_byte : search_start;
 800                         if (search_end <= *start) {
 801                                 ret = -ENOSPC;
 802                                 goto error;
 803                         }
 804                         goto check_pending;
 805                 }
 806                 btrfs_item_key_to_cpu(l, &key, slot);
 807
 808                 if (key.objectid < device->devid)
 809                         goto next;
 810
 811                 if (key.objectid > device->devid)
 812                         goto no_more_items;
 813
 814                 if (key.offset >= search_start && key.offset > last_byte &&
 815                     start_found) {
 816                         if (last_byte < search_start)
 817                                 last_byte = search_start;
 818                         hole_size = key.offset - last_byte;
 819
 820                         if (hole_size > *max_avail)
 821                                 *max_avail = hole_size;
 822
 823                         if (key.offset > last_byte &&
 824                             hole_size >= num_bytes) {
 825                                 *start = last_byte;
 826                                 goto check_pending;
 827                         }
 828                 }
 829                 if (btrfs_key_type(&key) != BTRFS_DEV_EXTENT_KEY)
 830                         goto next;
 831
 832                 start_found = 1;
 833                 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
 834                 last_byte = key.offset + btrfs_dev_extent_length(l, dev_extent);
 835 next:
 836                 path->slots[0]++;
 837                 cond_resched();
 838         }
 839 check_pending:
 840         /* we have to make sure we didn't find an extent that has already
 841          * been allocated by the map tree or the original allocation
 842          */
 843         BUG_ON(*start < search_start);
 844
 845         if (*start + num_bytes > search_end) {
 846                 ret = -ENOSPC;
 847                 goto error;
 848         }
 849         /* check for pending inserts here */
 850         ret = 0;
 851
 852 error:
 853         btrfs_free_path(path);
 854         return ret;
 855 }
 856
 857 static int btrfs_free_dev_extent(struct btrfs_trans_handle *trans,
 858                           struct btrfs_device *device,
 859                           u64 start)
 860 {
 861         int ret;
 862         struct btrfs_path *path;
 863         struct btrfs_root *root = device->dev_root;
 864         struct btrfs_key key;
 865         struct btrfs_key found_key;
 866         struct extent_buffer *leaf = NULL;
 867         struct btrfs_dev_extent *extent = NULL;
 868
 869         path = btrfs_alloc_path();
 870         if (!path)
 871                 return -ENOMEM;
 872
 873         key.objectid = device->devid;
 874         key.offset = start;
 875         key.type = BTRFS_DEV_EXTENT_KEY;
 876
 877         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
 878         if (ret > 0) {
 879                 ret = btrfs_previous_item(root, path, key.objectid,
 880                                           BTRFS_DEV_EXTENT_KEY);
 881                 BUG_ON(ret);
 882                 leaf = path->nodes[0];
 883                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
 884                 extent = btrfs_item_ptr(leaf, path->slots[0],
 885                                         struct btrfs_dev_extent);
 886                 BUG_ON(found_key.offset > start || found_key.offset +
 887                        btrfs_dev_extent_length(leaf, extent) < start);
 888                 ret = 0;
 889         } else if (ret == 0) {
 890                 leaf = path->nodes[0];
 891                 extent = btrfs_item_ptr(leaf, path->slots[0],
 892                                         struct btrfs_dev_extent);
 893         }
 894         BUG_ON(ret);
 895
 896         if (device->bytes_used > 0)
 897                 device->bytes_used -= btrfs_dev_extent_length(leaf, extent);
 898         ret = btrfs_del_item(trans, root, path);
 899         BUG_ON(ret);
 900
 901         btrfs_free_path(path);
 902         return ret;
 903 }
 904
 905 int btrfs_alloc_dev_extent(struct btrfs_trans_handle *trans,
 906                            struct btrfs_device *device,
 907                            u64 chunk_tree, u64 chunk_objectid,
 908                            u64 chunk_offset, u64 start, u64 num_bytes)
 909 {
 910         int ret;
 911         struct btrfs_path *path;
 912         struct btrfs_root *root = device->dev_root;
 913         struct btrfs_dev_extent *extent;
 914         struct extent_buffer *leaf;
 915         struct btrfs_key key;
 916
 917         WARN_ON(!device->in_fs_metadata);
 918         path = btrfs_alloc_path();
 919         if (!path)
 920                 return -ENOMEM;
 921
 922         key.objectid = device->devid;
 923         key.offset = start;
 924         key.type = BTRFS_DEV_EXTENT_KEY;
 925         ret = btrfs_insert_empty_item(trans, root, path, &key,
 926                                       sizeof(*extent));
 927         BUG_ON(ret);
 928
 929         leaf = path->nodes[0];
 930         extent = btrfs_item_ptr(leaf, path->slots[0],
 931                                 struct btrfs_dev_extent);
 932         btrfs_set_dev_extent_chunk_tree(leaf, extent, chunk_tree);
 933         btrfs_set_dev_extent_chunk_objectid(leaf, extent, chunk_objectid);
 934         btrfs_set_dev_extent_chunk_offset(leaf, extent, chunk_offset);
 935
 936         write_extent_buffer(leaf, root->fs_info->chunk_tree_uuid,
 937                     (unsigned long)btrfs_dev_extent_chunk_tree_uuid(extent),
 938                     BTRFS_UUID_SIZE);
 939
 940         btrfs_set_dev_extent_length(leaf, extent, num_bytes);
 941         btrfs_mark_buffer_dirty(leaf);
 942         btrfs_free_path(path);
 943         return ret;
 944 }
 945
 946 static noinline int find_next_chunk(struct btrfs_root *root,
 947                                     u64 objectid, u64 *offset)
 948 {
 949         struct btrfs_path *path;
 950         int ret;
 951         struct btrfs_key key;
 952         struct btrfs_chunk *chunk;
 953         struct btrfs_key found_key;
 954
 955         path = btrfs_alloc_path();
 956         BUG_ON(!path);
 957
 958         key.objectid = objectid;
 959         key.offset = (u64)-1;
 960         key.type = BTRFS_CHUNK_ITEM_KEY;
 961
 962         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 963         if (ret < 0)
 964                 goto error;
 965
 966         BUG_ON(ret == 0);
 967
 968         ret = btrfs_previous_item(root, path, 0, BTRFS_CHUNK_ITEM_KEY);
 969         if (ret) {
 970                 *offset = 0;
 971         } else {
 972                 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
 973                                       path->slots[0]);
 974                 if (found_key.objectid != objectid)
 975                         *offset = 0;
 976                 else {
 977                         chunk = btrfs_item_ptr(path->nodes[0], path->slots[0],
 978                                                struct btrfs_chunk);
 979                         *offset = found_key.offset +
 980                                 btrfs_chunk_length(path->nodes[0], chunk);
 981                 }
 982         }
 983         ret = 0;
 984 error:
 985         btrfs_free_path(path);
 986         return ret;
 987 }
 988
 989 static noinline int find_next_devid(struct btrfs_root *root, u64 *objectid)
 990 {
 991         int ret;
 992         struct btrfs_key key;
 993         struct btrfs_key found_key;
 994         struct btrfs_path *path;
 995
 996         root = root->fs_info->chunk_root;
 997
 998         path = btrfs_alloc_path();
 999         if (!path)
1000                 return -ENOMEM;
1001
1002         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1003         key.type = BTRFS_DEV_ITEM_KEY;
1004         key.offset = (u64)-1;
1005
1006         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1007         if (ret < 0)
1008                 goto error;
1009
1010         BUG_ON(ret == 0);
1011
1012         ret = btrfs_previous_item(root, path, BTRFS_DEV_ITEMS_OBJECTID,
1013                                   BTRFS_DEV_ITEM_KEY);
1014         if (ret) {
1015                 *objectid = 1;
1016         } else {
1017                 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
1018                                       path->slots[0]);
1019                 *objectid = found_key.offset + 1;
1020         }
1021         ret = 0;
1022 error:
1023         btrfs_free_path(path);
1024         return ret;
1025 }
1026
1027 /*
1028  * the device information is stored in the chunk root
1029  * the btrfs_device struct should be fully filled in
1030  */
1031 int btrfs_add_device(struct btrfs_trans_handle *trans,
1032                      struct btrfs_root *root,
1033                      struct btrfs_device *device)
1034 {
1035         int ret;
1036         struct btrfs_path *path;
1037         struct btrfs_dev_item *dev_item;
1038         struct extent_buffer *leaf;
1039         struct btrfs_key key;
1040         unsigned long ptr;
1041
1042         root = root->fs_info->chunk_root;
1043
1044         path = btrfs_alloc_path();
1045         if (!path)
1046                 return -ENOMEM;
1047
1048         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1049         key.type = BTRFS_DEV_ITEM_KEY;
1050         key.offset = device->devid;
1051
1052         ret = btrfs_insert_empty_item(trans, root, path, &key,
1053                                       sizeof(*dev_item));
1054         if (ret)
1055                 goto out;
1056
1057         leaf = path->nodes[0];
1058         dev_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dev_item);
1059
1060         btrfs_set_device_id(leaf, dev_item, device->devid);
1061         btrfs_set_device_generation(leaf, dev_item, 0);
1062         btrfs_set_device_type(leaf, dev_item, device->type);
1063         btrfs_set_device_io_align(leaf, dev_item, device->io_align);
1064         btrfs_set_device_io_width(leaf, dev_item, device->io_width);
1065         btrfs_set_device_sector_size(leaf, dev_item, device->sector_size);
1066         btrfs_set_device_total_bytes(leaf, dev_item, device->total_bytes);
1067         btrfs_set_device_bytes_used(leaf, dev_item, device->bytes_used);
1068         btrfs_set_device_group(leaf, dev_item, 0);
1069         btrfs_set_device_seek_speed(leaf, dev_item, 0);
1070         btrfs_set_device_bandwidth(leaf, dev_item, 0);
1071         btrfs_set_device_start_offset(leaf, dev_item, 0);
1072
1073         ptr = (unsigned long)btrfs_device_uuid(dev_item);
1074         write_extent_buffer(leaf, device->uuid, ptr, BTRFS_UUID_SIZE);
1075         ptr = (unsigned long)btrfs_device_fsid(dev_item);
1076         write_extent_buffer(leaf, root->fs_info->fsid, ptr, BTRFS_UUID_SIZE);
1077         btrfs_mark_buffer_dirty(leaf);
1078
1079         ret = 0;
1080 out:
1081         btrfs_free_path(path);
1082         return ret;
1083 }
1084
1085 static int btrfs_rm_dev_item(struct btrfs_root *root,
1086                              struct btrfs_device *device)
1087 {
1088         int ret;
1089         struct btrfs_path *path;
1090         struct btrfs_key key;
1091         struct btrfs_trans_handle *trans;
1092
1093         root = root->fs_info->chunk_root;
1094
1095         path = btrfs_alloc_path();
1096         if (!path)
1097                 return -ENOMEM;
1098
1099         trans = btrfs_start_transaction(root, 1);
1100         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1101         key.type = BTRFS_DEV_ITEM_KEY;
1102         key.offset = device->devid;
1103         lock_chunks(root);
1104
1105         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1106         if (ret < 0)
1107                 goto out;
1108
1109         if (ret > 0) {
1110                 ret = -ENOENT;
1111                 goto out;
1112         }
1113
1114         ret = btrfs_del_item(trans, root, path);
1115         if (ret)
1116                 goto out;
1117 out:
1118         btrfs_free_path(path);
1119         unlock_chunks(root);
1120         btrfs_commit_transaction(trans, root);
1121         return ret;
1122 }
1123
1124 int btrfs_rm_device(struct btrfs_root *root, char *device_path)
1125 {
1126         struct btrfs_device *device;
1127         struct btrfs_device *next_device;
1128         struct block_device *bdev;
1129         struct buffer_head *bh = NULL;
1130         struct btrfs_super_block *disk_super;
1131         u64 all_avail;
1132         u64 devid;
1133         u64 num_devices;
1134         u8 *dev_uuid;
1135         int ret = 0;
1136
1137         mutex_lock(&uuid_mutex);
1138         mutex_lock(&root->fs_info->volume_mutex);
1139
1140         all_avail = root->fs_info->avail_data_alloc_bits |
1141                 root->fs_info->avail_system_alloc_bits |
1142                 root->fs_info->avail_metadata_alloc_bits;
1143
1144         if ((all_avail & BTRFS_BLOCK_GROUP_RAID10) &&
1145             root->fs_info->fs_devices->num_devices <= 4) {
1146                 printk(KERN_ERR "btrfs: unable to go below four devices "
1147                        "on raid10\n");
1148                 ret = -EINVAL;
1149                 goto out;
1150         }
1151
1152         if ((all_avail & BTRFS_BLOCK_GROUP_RAID1) &&
1153             root->fs_info->fs_devices->num_devices <= 2) {
1154                 printk(KERN_ERR "btrfs: unable to go below two "
1155                        "devices on raid1\n");
1156                 ret = -EINVAL;
1157                 goto out;
1158         }
1159
1160         if (strcmp(device_path, "missing") == 0) {
1161                 struct list_head *devices;
1162                 struct btrfs_device *tmp;
1163
1164                 device = NULL;
1165                 devices = &root->fs_info->fs_devices->devices;
1166                 mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
1167                 list_for_each_entry(tmp, devices, dev_list) {
1168                         if (tmp->in_fs_metadata && !tmp->bdev) {
1169                                 device = tmp;
1170                                 break;
1171                         }
1172                 }
1173                 mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1174                 bdev = NULL;
1175                 bh = NULL;
1176                 disk_super = NULL;
1177                 if (!device) {
1178                         printk(KERN_ERR "btrfs: no missing devices found to "
1179                                "remove\n");
1180                         goto out;
1181                 }
1182         } else {
1183                 bdev = open_bdev_exclusive(device_path, FMODE_READ,
1184                                       root->fs_info->bdev_holder);
1185                 if (IS_ERR(bdev)) {
1186                         ret = PTR_ERR(bdev);
1187                         goto out;
1188                 }
1189
1190                 set_blocksize(bdev, 4096);
1191                 bh = btrfs_read_dev_super(bdev);
1192                 if (!bh) {
1193                         ret = -EIO;
1194                         goto error_close;
1195                 }
1196                 disk_super = (struct btrfs_super_block *)bh->b_data;
1197                 devid = btrfs_stack_device_id(&disk_super->dev_item);
1198                 dev_uuid = disk_super->dev_item.uuid;
1199                 device = btrfs_find_device(root, devid, dev_uuid,
1200                                            disk_super->fsid);
1201                 if (!device) {
1202                         ret = -ENOENT;
1203                         goto error_brelse;
1204                 }
1205         }
1206
1207         if (device->writeable && root->fs_info->fs_devices->rw_devices == 1) {
1208                 printk(KERN_ERR "btrfs: unable to remove the only writeable "
1209                        "device\n");
1210                 ret = -EINVAL;
1211                 goto error_brelse;
1212         }
1213
1214         if (device->writeable) {
1215                 list_del_init(&device->dev_alloc_list);
1216                 root->fs_info->fs_devices->rw_devices--;
1217         }
1218
1219         ret = btrfs_shrink_device(device, 0);
1220         if (ret)
1221                 goto error_brelse;
1222
1223         ret = btrfs_rm_dev_item(root->fs_info->chunk_root, device);
1224         if (ret)
1225                 goto error_brelse;
1226
1227         device->in_fs_metadata = 0;
1228
1229         /*
1230          * the device list mutex makes sure that we don't change
1231          * the device list while someone else is writing out all
1232          * the device supers.
1233          */
1234         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
1235         list_del_init(&device->dev_list);
1236         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1237
1238         device->fs_devices->num_devices--;
1239
1240         next_device = list_entry(root->fs_info->fs_devices->devices.next,
1241                                  struct btrfs_device, dev_list);
1242         if (device->bdev == root->fs_info->sb->s_bdev)
1243                 root->fs_info->sb->s_bdev = next_device->bdev;
1244         if (device->bdev == root->fs_info->fs_devices->latest_bdev)
1245                 root->fs_info->fs_devices->latest_bdev = next_device->bdev;
1246
1247         if (device->bdev) {
1248                 close_bdev_exclusive(device->bdev, device->mode);
1249                 device->bdev = NULL;
1250                 device->fs_devices->open_devices--;
1251         }
1252
1253         num_devices = btrfs_super_num_devices(&root->fs_info->super_copy) - 1;
1254         btrfs_set_super_num_devices(&root->fs_info->super_copy, num_devices);
1255
1256         if (device->fs_devices->open_devices == 0) {
1257                 struct btrfs_fs_devices *fs_devices;
1258                 fs_devices = root->fs_info->fs_devices;
1259                 while (fs_devices) {
1260                         if (fs_devices->seed == device->fs_devices)
1261                                 break;
1262                         fs_devices = fs_devices->seed;
1263                 }
1264                 fs_devices->seed = device->fs_devices->seed;
1265                 device->fs_devices->seed = NULL;
1266                 __btrfs_close_devices(device->fs_devices);
1267                 free_fs_devices(device->fs_devices);
1268         }
1269
1270         /*
1271          * at this point, the device is zero sized.  We want to
1272          * remove it from the devices list and zero out the old super
1273          */
1274         if (device->writeable) {
1275                 /* make sure this device isn't detected as part of
1276                  * the FS anymore
1277                  */
1278                 memset(&disk_super->magic, 0, sizeof(disk_super->magic));
1279                 set_buffer_dirty(bh);
1280                 sync_dirty_buffer(bh);
1281         }
1282
1283         kfree(device->name);
1284         kfree(device);
1285         ret = 0;
1286
1287 error_brelse:
1288         brelse(bh);
1289 error_close:
1290         if (bdev)
1291                 close_bdev_exclusive(bdev, FMODE_READ);
1292 out:
1293         mutex_unlock(&root->fs_info->volume_mutex);
1294         mutex_unlock(&uuid_mutex);
1295         return ret;
1296 }
1297
1298 /*
1299  * does all the dirty work required for changing file system's UUID.
1300  */
1301 static int btrfs_prepare_sprout(struct btrfs_trans_handle *trans,
1302                                 struct btrfs_root *root)
1303 {
1304         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
1305         struct btrfs_fs_devices *old_devices;
1306         struct btrfs_fs_devices *seed_devices;
1307         struct btrfs_super_block *disk_super = &root->fs_info->super_copy;
1308         struct btrfs_device *device;
1309         u64 super_flags;
1310
1311         BUG_ON(!mutex_is_locked(&uuid_mutex));
1312         if (!fs_devices->seeding)
1313                 return -EINVAL;
1314
1315         seed_devices = kzalloc(sizeof(*fs_devices), GFP_NOFS);
1316         if (!seed_devices)
1317                 return -ENOMEM;
1318
1319         old_devices = clone_fs_devices(fs_devices);
1320         if (IS_ERR(old_devices)) {
1321                 kfree(seed_devices);
1322                 return PTR_ERR(old_devices);
1323         }
1324
1325         list_add(&old_devices->list, &fs_uuids);
1326
1327         memcpy(seed_devices, fs_devices, sizeof(*seed_devices));
1328         seed_devices->opened = 1;
1329         INIT_LIST_HEAD(&seed_devices->devices);
1330         INIT_LIST_HEAD(&seed_devices->alloc_list);
1331         mutex_init(&seed_devices->device_list_mutex);
1332         list_splice_init(&fs_devices->devices, &seed_devices->devices);
1333         list_splice_init(&fs_devices->alloc_list, &seed_devices->alloc_list);
1334         list_for_each_entry(device, &seed_devices->devices, dev_list) {
1335                 device->fs_devices = seed_devices;
1336         }
1337
1338         fs_devices->seeding = 0;
1339         fs_devices->num_devices = 0;
1340         fs_devices->open_devices = 0;
1341         fs_devices->seed = seed_devices;
1342
1343         generate_random_uuid(fs_devices->fsid);
1344         memcpy(root->fs_info->fsid, fs_devices->fsid, BTRFS_FSID_SIZE);
1345         memcpy(disk_super->fsid, fs_devices->fsid, BTRFS_FSID_SIZE);
1346         super_flags = btrfs_super_flags(disk_super) &
1347                       ~BTRFS_SUPER_FLAG_SEEDING;
1348         btrfs_set_super_flags(disk_super, super_flags);
1349
1350         return 0;
1351 }
1352
1353 /*
1354  * strore the expected generation for seed devices in device items.
1355  */
1356 static int btrfs_finish_sprout(struct btrfs_trans_handle *trans,
1357                                struct btrfs_root *root)
1358 {
1359         struct btrfs_path *path;
1360         struct extent_buffer *leaf;
1361         struct btrfs_dev_item *dev_item;
1362         struct btrfs_device *device;
1363         struct btrfs_key key;
1364         u8 fs_uuid[BTRFS_UUID_SIZE];
1365         u8 dev_uuid[BTRFS_UUID_SIZE];
1366         u64 devid;
1367         int ret;
1368
1369         path = btrfs_alloc_path();
1370         if (!path)
1371                 return -ENOMEM;
1372
1373         root = root->fs_info->chunk_root;
1374         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1375         key.offset = 0;
1376         key.type = BTRFS_DEV_ITEM_KEY;
1377
1378         while (1) {
1379                 ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
1380                 if (ret < 0)
1381                         goto error;
1382
1383                 leaf = path->nodes[0];
1384 next_slot:
1385                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
1386                         ret = btrfs_next_leaf(root, path);
1387                         if (ret > 0)
1388                                 break;
1389                         if (ret < 0)
1390                                 goto error;
1391                         leaf = path->nodes[0];
1392                         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1393                         btrfs_release_path(root, path);
1394                         continue;
1395                 }
1396
1397                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1398                 if (key.objectid != BTRFS_DEV_ITEMS_OBJECTID ||
1399                     key.type != BTRFS_DEV_ITEM_KEY)
1400                         break;
1401
1402                 dev_item = btrfs_item_ptr(leaf, path->slots[0],
1403                                           struct btrfs_dev_item);
1404                 devid = btrfs_device_id(leaf, dev_item);
1405                 read_extent_buffer(leaf, dev_uuid,
1406                                    (unsigned long)btrfs_device_uuid(dev_item),
1407                                    BTRFS_UUID_SIZE);
1408                 read_extent_buffer(leaf, fs_uuid,
1409                                    (unsigned long)btrfs_device_fsid(dev_item),
1410                                    BTRFS_UUID_SIZE);
1411                 device = btrfs_find_device(root, devid, dev_uuid, fs_uuid);
1412                 BUG_ON(!device);
1413
1414                 if (device->fs_devices->seeding) {
1415                         btrfs_set_device_generation(leaf, dev_item,
1416                                                     device->generation);
1417                         btrfs_mark_buffer_dirty(leaf);
1418                 }
1419
1420                 path->slots[0]++;
1421                 goto next_slot;
1422         }
1423         ret = 0;
1424 error:
1425         btrfs_free_path(path);
1426         return ret;
1427 }
1428
1429 int btrfs_init_new_device(struct btrfs_root *root, char *device_path)
1430 {
1431         struct btrfs_trans_handle *trans;
1432         struct btrfs_device *device;
1433         struct block_device *bdev;
1434         struct list_head *devices;
1435         struct super_block *sb = root->fs_info->sb;
1436         u64 total_bytes;
1437         int seeding_dev = 0;
1438         int ret = 0;
1439
1440         if ((sb->s_flags & MS_RDONLY) && !root->fs_info->fs_devices->seeding)
1441                 return -EINVAL;
1442
1443         bdev = open_bdev_exclusive(device_path, 0, root->fs_info->bdev_holder);
1444         if (IS_ERR(bdev))
1445                 return PTR_ERR(bdev);
1446
1447         if (root->fs_info->fs_devices->seeding) {
1448                 seeding_dev = 1;
1449                 down_write(&sb->s_umount);
1450                 mutex_lock(&uuid_mutex);
1451         }
1452
1453         filemap_write_and_wait(bdev->bd_inode->i_mapping);
1454         mutex_lock(&root->fs_info->volume_mutex);
1455
1456         devices = &root->fs_info->fs_devices->devices;
1457         /*
1458          * we have the volume lock, so we don't need the extra
1459          * device list mutex while reading the list here.
1460          */
1461         list_for_each_entry(device, devices, dev_list) {
1462                 if (device->bdev == bdev) {
1463                         ret = -EEXIST;
1464                         goto error;
1465                 }
1466         }
1467
1468         device = kzalloc(sizeof(*device), GFP_NOFS);
1469         if (!device) {
1470                 /* we can safely leave the fs_devices entry around */
1471                 ret = -ENOMEM;
1472                 goto error;
1473         }
1474
1475         device->name = kstrdup(device_path, GFP_NOFS);
1476         if (!device->name) {
1477                 kfree(device);
1478                 ret = -ENOMEM;
1479                 goto error;
1480         }
1481
1482         ret = find_next_devid(root, &device->devid);
1483         if (ret) {
1484                 kfree(device);
1485                 goto error;
1486         }
1487
1488         trans = btrfs_start_transaction(root, 1);
1489         lock_chunks(root);
1490
1491         device->barriers = 1;
1492         device->writeable = 1;
1493         device->work.func = pending_bios_fn;
1494         generate_random_uuid(device->uuid);
1495         spin_lock_init(&device->io_lock);
1496         device->generation = trans->transid;
1497         device->io_width = root->sectorsize;
1498         device->io_align = root->sectorsize;
1499         device->sector_size = root->sectorsize;
1500         device->total_bytes = i_size_read(bdev->bd_inode);
1501         device->disk_total_bytes = device->total_bytes;
1502         device->dev_root = root->fs_info->dev_root;
1503         device->bdev = bdev;
1504         device->in_fs_metadata = 1;
1505         device->mode = 0;
1506         set_blocksize(device->bdev, 4096);
1507
1508         if (seeding_dev) {
1509                 sb->s_flags &= ~MS_RDONLY;
1510                 ret = btrfs_prepare_sprout(trans, root);
1511                 BUG_ON(ret);
1512         }
1513
1514         device->fs_devices = root->fs_info->fs_devices;
1515
1516         /*
1517          * we don't want write_supers to jump in here with our device
1518          * half setup
1519          */
1520         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
1521         list_add(&device->dev_list, &root->fs_info->fs_devices->devices);
1522         list_add(&device->dev_alloc_list,
1523                  &root->fs_info->fs_devices->alloc_list);
1524         root->fs_info->fs_devices->num_devices++;
1525         root->fs_info->fs_devices->open_devices++;
1526         root->fs_info->fs_devices->rw_devices++;
1527         root->fs_info->fs_devices->total_rw_bytes += device->total_bytes;
1528
1529         if (!blk_queue_nonrot(bdev_get_queue(bdev)))
1530                 root->fs_info->fs_devices->rotating = 1;
1531
1532         total_bytes = btrfs_super_total_bytes(&root->fs_info->super_copy);
1533         btrfs_set_super_total_bytes(&root->fs_info->super_copy,
1534                                     total_bytes + device->total_bytes);
1535
1536         total_bytes = btrfs_super_num_devices(&root->fs_info->super_copy);
1537         btrfs_set_super_num_devices(&root->fs_info->super_copy,
1538                                     total_bytes + 1);
1539         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1540
1541         if (seeding_dev) {
1542                 ret = init_first_rw_device(trans, root, device);
1543                 BUG_ON(ret);
1544                 ret = btrfs_finish_sprout(trans, root);
1545                 BUG_ON(ret);
1546         } else {
1547                 ret = btrfs_add_device(trans, root, device);
1548         }
1549
1550         /*
1551          * we've got more storage, clear any full flags on the space
1552          * infos
1553          */
1554         btrfs_clear_space_info_full(root->fs_info);
1555
1556         unlock_chunks(root);
1557         btrfs_commit_transaction(trans, root);
1558
1559         if (seeding_dev) {
1560                 mutex_unlock(&uuid_mutex);
1561                 up_write(&sb->s_umount);
1562
1563                 ret = btrfs_relocate_sys_chunks(root);
1564                 BUG_ON(ret);
1565         }
1566 out:
1567         mutex_unlock(&root->fs_info->volume_mutex);
1568         return ret;
1569 error:
1570         close_bdev_exclusive(bdev, 0);
1571         if (seeding_dev) {
1572                 mutex_unlock(&uuid_mutex);
1573                 up_write(&sb->s_umount);
1574         }
1575         goto out;
1576 }
1577
1578 static noinline int btrfs_update_device(struct btrfs_trans_handle *trans,
1579                                         struct btrfs_device *device)
1580 {
1581         int ret;
1582         struct btrfs_path *path;
1583         struct btrfs_root *root;
1584         struct btrfs_dev_item *dev_item;
1585         struct extent_buffer *leaf;
1586         struct btrfs_key key;
1587
1588         root = device->dev_root->fs_info->chunk_root;
1589
1590         path = btrfs_alloc_path();
1591         if (!path)
1592                 return -ENOMEM;
1593
1594         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1595         key.type = BTRFS_DEV_ITEM_KEY;
1596         key.offset = device->devid;
1597
1598         ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
1599         if (ret < 0)
1600                 goto out;
1601
1602         if (ret > 0) {
1603                 ret = -ENOENT;
1604                 goto out;
1605         }
1606
1607         leaf = path->nodes[0];
1608         dev_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dev_item);
1609
1610         btrfs_set_device_id(leaf, dev_item, device->devid);
1611         btrfs_set_device_type(leaf, dev_item, device->type);
1612         btrfs_set_device_io_align(leaf, dev_item, device->io_align);
1613         btrfs_set_device_io_width(leaf, dev_item, device->io_width);
1614         btrfs_set_device_sector_size(leaf, dev_item, device->sector_size);
1615         btrfs_set_device_total_bytes(leaf, dev_item, device->disk_total_bytes);
1616         btrfs_set_device_bytes_used(leaf, dev_item, device->bytes_used);
1617         btrfs_mark_buffer_dirty(leaf);
1618
1619 out:
1620         btrfs_free_path(path);
1621         return ret;
1622 }
1623
1624 static int __btrfs_grow_device(struct btrfs_trans_handle *trans,
1625                       struct btrfs_device *device, u64 new_size)
1626 {
1627         struct btrfs_super_block *super_copy =
1628                 &device->dev_root->fs_info->super_copy;
1629         u64 old_total = btrfs_super_total_bytes(super_copy);
1630         u64 diff = new_size - device->total_bytes;
1631
1632         if (!device->writeable)
1633                 return -EACCES;
1634         if (new_size <= device->total_bytes)
1635                 return -EINVAL;
1636
1637         btrfs_set_super_total_bytes(super_copy, old_total + diff);
1638         device->fs_devices->total_rw_bytes += diff;
1639
1640         device->total_bytes = new_size;
1641         device->disk_total_bytes = new_size;
1642         btrfs_clear_space_info_full(device->dev_root->fs_info);
1643
1644         return btrfs_update_device(trans, device);
1645 }
1646
1647 int btrfs_grow_device(struct btrfs_trans_handle *trans,
1648                       struct btrfs_device *device, u64 new_size)
1649 {
1650         int ret;
1651         lock_chunks(device->dev_root);
1652         ret = __btrfs_grow_device(trans, device, new_size);
1653         unlock_chunks(device->dev_root);
1654         return ret;
1655 }
1656
1657 static int btrfs_free_chunk(struct btrfs_trans_handle *trans,
1658                             struct btrfs_root *root,
1659                             u64 chunk_tree, u64 chunk_objectid,
1660                             u64 chunk_offset)
1661 {
1662         int ret;
1663         struct btrfs_path *path;
1664         struct btrfs_key key;
1665
1666         root = root->fs_info->chunk_root;
1667         path = btrfs_alloc_path();
1668         if (!path)
1669                 return -ENOMEM;
1670
1671         key.objectid = chunk_objectid;
1672         key.offset = chunk_offset;
1673         key.type = BTRFS_CHUNK_ITEM_KEY;
1674
1675         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1676         BUG_ON(ret);
1677
1678         ret = btrfs_del_item(trans, root, path);
1679         BUG_ON(ret);
1680
1681         btrfs_free_path(path);
1682         return 0;
1683 }
1684
1685 static int btrfs_del_sys_chunk(struct btrfs_root *root, u64 chunk_objectid, u64
1686                         chunk_offset)
1687 {
1688         struct btrfs_super_block *super_copy = &root->fs_info->super_copy;
1689         struct btrfs_disk_key *disk_key;
1690         struct btrfs_chunk *chunk;
1691         u8 *ptr;
1692         int ret = 0;
1693         u32 num_stripes;
1694         u32 array_size;
1695         u32 len = 0;
1696         u32 cur;
1697         struct btrfs_key key;
1698
1699         array_size = btrfs_super_sys_array_size(super_copy);
1700
1701         ptr = super_copy->sys_chunk_array;
1702         cur = 0;
1703
1704         while (cur < array_size) {
1705                 disk_key = (struct btrfs_disk_key *)ptr;
1706                 btrfs_disk_key_to_cpu(&key, disk_key);
1707
1708                 len = sizeof(*disk_key);
1709
1710                 if (key.type == BTRFS_CHUNK_ITEM_KEY) {
1711                         chunk = (struct btrfs_chunk *)(ptr + len);
1712                         num_stripes = btrfs_stack_chunk_num_stripes(chunk);
1713                         len += btrfs_chunk_item_size(num_stripes);
1714                 } else {
1715                         ret = -EIO;
1716                         break;
1717                 }
1718                 if (key.objectid == chunk_objectid &&
1719                     key.offset == chunk_offset) {
1720                         memmove(ptr, ptr + len, array_size - (cur + len));
1721                         array_size -= len;
1722                         btrfs_set_super_sys_array_size(super_copy, array_size);
1723                 } else {
1724                         ptr += len;
1725                         cur += len;
1726                 }
1727         }
1728         return ret;
1729 }
1730
1731 static int btrfs_relocate_chunk(struct btrfs_root *root,
1732                          u64 chunk_tree, u64 chunk_objectid,
1733                          u64 chunk_offset)
1734 {
1735         struct extent_map_tree *em_tree;
1736         struct btrfs_root *extent_root;
1737         struct btrfs_trans_handle *trans;
1738         struct extent_map *em;
1739         struct map_lookup *map;
1740         int ret;
1741         int i;
1742
1743         root = root->fs_info->chunk_root;
1744         extent_root = root->fs_info->extent_root;
1745         em_tree = &root->fs_info->mapping_tree.map_tree;
1746
1747         ret = btrfs_can_relocate(extent_root, chunk_offset);
1748         if (ret)
1749                 return -ENOSPC;
1750
1751         /* step one, relocate all the extents inside this chunk */
1752         ret = btrfs_relocate_block_group(extent_root, chunk_offset);
1753         BUG_ON(ret);
1754
1755         trans = btrfs_start_transaction(root, 1);
1756         BUG_ON(!trans);
1757
1758         lock_chunks(root);
1759
1760         /*
1761          * step two, delete the device extents and the
1762          * chunk tree entries
1763          */
1764         read_lock(&em_tree->lock);
1765         em = lookup_extent_mapping(em_tree, chunk_offset, 1);
1766         read_unlock(&em_tree->lock);
1767
1768         BUG_ON(em->start > chunk_offset ||
1769                em->start + em->len < chunk_offset);
1770         map = (struct map_lookup *)em->bdev;
1771
1772         for (i = 0; i < map->num_stripes; i++) {
1773                 ret = btrfs_free_dev_extent(trans, map->stripes[i].dev,
1774                                             map->stripes[i].physical);
1775                 BUG_ON(ret);
1776
1777                 if (map->stripes[i].dev) {
1778                         ret = btrfs_update_device(trans, map->stripes[i].dev);
1779                         BUG_ON(ret);
1780                 }
1781         }
1782         ret = btrfs_free_chunk(trans, root, chunk_tree, chunk_objectid,
1783                                chunk_offset);
1784
1785         BUG_ON(ret);
1786
1787         if (map->type & BTRFS_BLOCK_GROUP_SYSTEM) {
1788                 ret = btrfs_del_sys_chunk(root, chunk_objectid, chunk_offset);
1789                 BUG_ON(ret);
1790         }
1791
1792         ret = btrfs_remove_block_group(trans, extent_root, chunk_offset);
1793         BUG_ON(ret);
1794
1795         write_lock(&em_tree->lock);
1796         remove_extent_mapping(em_tree, em);
1797         write_unlock(&em_tree->lock);
1798
1799         kfree(map);
1800         em->bdev = NULL;
1801
1802         /* once for the tree */
1803         free_extent_map(em);
1804         /* once for us */
1805         free_extent_map(em);
1806
1807         unlock_chunks(root);
1808         btrfs_end_transaction(trans, root);
1809         return 0;
1810 }
1811
1812 static int btrfs_relocate_sys_chunks(struct btrfs_root *root)
1813 {
1814         struct btrfs_root *chunk_root = root->fs_info->chunk_root;
1815         struct btrfs_path *path;
1816         struct extent_buffer *leaf;
1817         struct btrfs_chunk *chunk;
1818         struct btrfs_key key;
1819         struct btrfs_key found_key;
1820         u64 chunk_tree = chunk_root->root_key.objectid;
1821         u64 chunk_type;
1822         bool retried = false;
1823         int failed = 0;
1824         int ret;
1825
1826         path = btrfs_alloc_path();
1827         if (!path)
1828                 return -ENOMEM;
1829
1830 again:
1831         key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
1832         key.offset = (u64)-1;
1833         key.type = BTRFS_CHUNK_ITEM_KEY;
1834
1835         while (1) {
1836                 ret = btrfs_search_slot(NULL, chunk_root, &key, path, 0, 0);
1837                 if (ret < 0)
1838                         goto error;
1839                 BUG_ON(ret == 0);
1840
1841                 ret = btrfs_previous_item(chunk_root, path, key.objectid,
1842                                           key.type);
1843                 if (ret < 0)
1844                         goto error;
1845                 if (ret > 0)
1846                         break;
1847
1848                 leaf = path->nodes[0];
1849                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1850
1851                 chunk = btrfs_item_ptr(leaf, path->slots[0],
1852                                        struct btrfs_chunk);
1853                 chunk_type = btrfs_chunk_type(leaf, chunk);
1854                 btrfs_release_path(chunk_root, path);
1855
1856                 if (chunk_type & BTRFS_BLOCK_GROUP_SYSTEM) {
1857                         ret = btrfs_relocate_chunk(chunk_root, chunk_tree,
1858                                                    found_key.objectid,
1859                                                    found_key.offset);
1860                         if (ret == -ENOSPC)
1861                                 failed++;
1862                         else if (ret)
1863                                 BUG();
1864                 }
1865
1866                 if (found_key.offset == 0)
1867                         break;
1868                 key.offset = found_key.offset - 1;
1869         }
1870         ret = 0;
1871         if (failed && !retried) {
1872                 failed = 0;
1873                 retried = true;
1874                 goto again;
1875         } else if (failed && retried) {
1876                 WARN_ON(1);
1877                 ret = -ENOSPC;
1878         }
1879 error:
1880         btrfs_free_path(path);
1881         return ret;
1882 }
1883
1884 static u64 div_factor(u64 num, int factor)
1885 {
1886         if (factor == 10)
1887                 return num;
1888         num *= factor;
1889         do_div(num, 10);
1890         return num;
1891 }
1892
1893 int btrfs_balance(struct btrfs_root *dev_root)
1894 {
1895         int ret;
1896         struct list_head *devices = &dev_root->fs_info->fs_devices->devices;
1897         struct btrfs_device *device;
1898         u64 old_size;
1899         u64 size_to_free;
1900         struct btrfs_path *path;
1901         struct btrfs_key key;
1902         struct btrfs_chunk *chunk;
1903         struct btrfs_root *chunk_root = dev_root->fs_info->chunk_root;
1904         struct btrfs_trans_handle *trans;
1905         struct btrfs_key found_key;
1906
1907         if (dev_root->fs_info->sb->s_flags & MS_RDONLY)
1908                 return -EROFS;
1909
1910         mutex_lock(&dev_root->fs_info->volume_mutex);
1911         dev_root = dev_root->fs_info->dev_root;
1912
1913         /* step one make some room on all the devices */
1914         list_for_each_entry(device, devices, dev_list) {
1915                 old_size = device->total_bytes;
1916                 size_to_free = div_factor(old_size, 1);
1917                 size_to_free = min(size_to_free, (u64)1 * 1024 * 1024);
1918                 if (!device->writeable ||
1919                     device->total_bytes - device->bytes_used > size_to_free)
1920                         continue;
1921
1922                 ret = btrfs_shrink_device(device, old_size - size_to_free);
1923                 if (ret == -ENOSPC)
1924                         break;
1925                 BUG_ON(ret);
1926
1927                 trans = btrfs_start_transaction(dev_root, 1);
1928                 BUG_ON(!trans);
1929
1930                 ret = btrfs_grow_device(trans, device, old_size);
1931                 BUG_ON(ret);
1932
1933                 btrfs_end_transaction(trans, dev_root);
1934         }
1935
1936         /* step two, relocate all the chunks */
1937         path = btrfs_alloc_path();
1938         BUG_ON(!path);
1939
1940         key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
1941         key.offset = (u64)-1;
1942         key.type = BTRFS_CHUNK_ITEM_KEY;
1943
1944         while (1) {
1945                 ret = btrfs_search_slot(NULL, chunk_root, &key, path, 0, 0);
1946                 if (ret < 0)
1947                         goto error;
1948
1949                 /*
1950                  * this shouldn't happen, it means the last relocate
1951                  * failed
1952                  */
1953                 if (ret == 0)
1954                         break;
1955
1956                 ret = btrfs_previous_item(chunk_root, path, 0,
1957                                           BTRFS_CHUNK_ITEM_KEY);
1958                 if (ret)
1959                         break;
1960
1961                 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
1962                                       path->slots[0]);
1963                 if (found_key.objectid != key.objectid)
1964                         break;
1965
1966                 chunk = btrfs_item_ptr(path->nodes[0],
1967                                        path->slots[0],
1968                                        struct btrfs_chunk);
1969                 /* chunk zero is special */
1970                 if (found_key.offset == 0)
1971                         break;
1972
1973                 btrfs_release_path(chunk_root, path);
1974                 ret = btrfs_relocate_chunk(chunk_root,
1975                                            chunk_root->root_key.objectid,
1976                                            found_key.objectid,
1977                                            found_key.offset);
1978                 BUG_ON(ret && ret != -ENOSPC);
1979                 key.offset = found_key.offset - 1;
1980         }
1981         ret = 0;
1982 error:
1983         btrfs_free_path(path);
1984         mutex_unlock(&dev_root->fs_info->volume_mutex);
1985         return ret;
1986 }
1987
1988 /*
1989  * shrinking a device means finding all of the device extents past
1990  * the new size, and then following the back refs to the chunks.
1991  * The chunk relocation code actually frees the device extent
1992  */
1993 int btrfs_shrink_device(struct btrfs_device *device, u64 new_size)
1994 {
1995         struct btrfs_trans_handle *trans;
1996         struct btrfs_root *root = device->dev_root;
1997         struct btrfs_dev_extent *dev_extent = NULL;
1998         struct btrfs_path *path;
1999         u64 length;
2000         u64 chunk_tree;
2001         u64 chunk_objectid;
2002         u64 chunk_offset;
2003         int ret;
2004         int slot;
2005         int failed = 0;
2006         bool retried = false;
2007         struct extent_buffer *l;
2008         struct btrfs_key key;
2009         struct btrfs_super_block *super_copy = &root->fs_info->super_copy;
2010         u64 old_total = btrfs_super_total_bytes(super_copy);
2011         u64 old_size = device->total_bytes;
2012         u64 diff = device->total_bytes - new_size;
2013
2014         if (new_size >= device->total_bytes)
2015                 return -EINVAL;
2016
2017         path = btrfs_alloc_path();
2018         if (!path)
2019                 return -ENOMEM;
2020
2021         path->reada = 2;
2022
2023         lock_chunks(root);
2024
2025         device->total_bytes = new_size;
2026         if (device->writeable)
2027                 device->fs_devices->total_rw_bytes -= diff;
2028         unlock_chunks(root);
2029
2030 again:
2031         key.objectid = device->devid;
2032         key.offset = (u64)-1;
2033         key.type = BTRFS_DEV_EXTENT_KEY;
2034
2035         while (1) {
2036                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2037                 if (ret < 0)
2038                         goto done;
2039
2040                 ret = btrfs_previous_item(root, path, 0, key.type);
2041                 if (ret < 0)
2042                         goto done;
2043                 if (ret) {
2044                         ret = 0;
2045                         btrfs_release_path(root, path);
2046                         break;
2047                 }
2048
2049                 l = path->nodes[0];
2050                 slot = path->slots[0];
2051                 btrfs_item_key_to_cpu(l, &key, path->slots[0]);
2052
2053                 if (key.objectid != device->devid) {
2054                         btrfs_release_path(root, path);
2055                         break;
2056                 }
2057
2058                 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
2059                 length = btrfs_dev_extent_length(l, dev_extent);
2060
2061                 if (key.offset + length <= new_size) {
2062                         btrfs_release_path(root, path);
2063                         break;
2064                 }
2065
2066                 chunk_tree = btrfs_dev_extent_chunk_tree(l, dev_extent);
2067                 chunk_objectid = btrfs_dev_extent_chunk_objectid(l, dev_extent);
2068                 chunk_offset = btrfs_dev_extent_chunk_offset(l, dev_extent);
2069                 btrfs_release_path(root, path);
2070
2071                 ret = btrfs_relocate_chunk(root, chunk_tree, chunk_objectid,
2072                                            chunk_offset);
2073                 if (ret && ret != -ENOSPC)
2074                         goto done;
2075                 if (ret == -ENOSPC)
2076                         failed++;
2077                 key.offset -= 1;
2078         }
2079
2080         if (failed && !retried) {
2081                 failed = 0;
2082                 retried = true;
2083                 goto again;
2084         } else if (failed && retried) {
2085                 ret = -ENOSPC;
2086                 lock_chunks(root);
2087
2088                 device->total_bytes = old_size;
2089                 if (device->writeable)
2090                         device->fs_devices->total_rw_bytes += diff;
2091                 unlock_chunks(root);
2092                 goto done;
2093         }
2094
2095         /* Shrinking succeeded, else we would be at "done". */
2096         trans = btrfs_start_transaction(root, 1);
2097         if (!trans) {
2098                 ret = -ENOMEM;
2099                 goto done;
2100         }
2101         lock_chunks(root);
2102
2103         device->disk_total_bytes = new_size;
2104         /* Now btrfs_update_device() will change the on-disk size. */
2105         ret = btrfs_update_device(trans, device);
2106         if (ret) {
2107                 unlock_chunks(root);
2108                 btrfs_end_transaction(trans, root);
2109                 goto done;
2110         }
2111         WARN_ON(diff > old_total);
2112         btrfs_set_super_total_bytes(super_copy, old_total - diff);
2113         unlock_chunks(root);
2114         btrfs_end_transaction(trans, root);
2115 done:
2116         btrfs_free_path(path);
2117         return ret;
2118 }
2119
2120 static int btrfs_add_system_chunk(struct btrfs_trans_handle *trans,
2121                            struct btrfs_root *root,
2122                            struct btrfs_key *key,
2123                            struct btrfs_chunk *chunk, int item_size)
2124 {
2125         struct btrfs_super_block *super_copy = &root->fs_info->super_copy;
2126         struct btrfs_disk_key disk_key;
2127         u32 array_size;
2128         u8 *ptr;
2129
2130         array_size = btrfs_super_sys_array_size(super_copy);
2131         if (array_size + item_size > BTRFS_SYSTEM_CHUNK_ARRAY_SIZE)
2132                 return -EFBIG;
2133
2134         ptr = super_copy->sys_chunk_array + array_size;
2135         btrfs_cpu_key_to_disk(&disk_key, key);
2136         memcpy(ptr, &disk_key, sizeof(disk_key));
2137         ptr += sizeof(disk_key);
2138         memcpy(ptr, chunk, item_size);
2139         item_size += sizeof(disk_key);
2140         btrfs_set_super_sys_array_size(super_copy, array_size + item_size);
2141         return 0;
2142 }
2143
2144 static noinline u64 chunk_bytes_by_type(u64 type, u64 calc_size,
2145                                         int num_stripes, int sub_stripes)
2146 {
2147         if (type & (BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_DUP))
2148                 return calc_size;
2149         else if (type & BTRFS_BLOCK_GROUP_RAID10)
2150                 return calc_size * (num_stripes / sub_stripes);
2151         else
2152                 return calc_size * num_stripes;
2153 }
2154
2155 static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
2156                                struct btrfs_root *extent_root,
2157                                struct map_lookup **map_ret,
2158                                u64 *num_bytes, u64 *stripe_size,
2159                                u64 start, u64 type)
2160 {
2161         struct btrfs_fs_info *info = extent_root->fs_info;
2162         struct btrfs_device *device = NULL;
2163         struct btrfs_fs_devices *fs_devices = info->fs_devices;
2164         struct list_head *cur;
2165         struct map_lookup *map = NULL;
2166         struct extent_map_tree *em_tree;
2167         struct extent_map *em;
2168         struct list_head private_devs;
2169         int min_stripe_size = 1 * 1024 * 1024;
2170         u64 calc_size = 1024 * 1024 * 1024;
2171         u64 max_chunk_size = calc_size;
2172         u64 min_free;
2173         u64 avail;
2174         u64 max_avail = 0;
2175         u64 dev_offset;
2176         int num_stripes = 1;
2177         int min_stripes = 1;
2178         int sub_stripes = 0;
2179         int looped = 0;
2180         int ret;
2181         int index;
2182         int stripe_len = 64 * 1024;
2183
2184         if ((type & BTRFS_BLOCK_GROUP_RAID1) &&
2185             (type & BTRFS_BLOCK_GROUP_DUP)) {
2186                 WARN_ON(1);
2187                 type &= ~BTRFS_BLOCK_GROUP_DUP;
2188         }
2189         if (list_empty(&fs_devices->alloc_list))
2190                 return -ENOSPC;
2191
2192         if (type & (BTRFS_BLOCK_GROUP_RAID0)) {
2193                 num_stripes = fs_devices->rw_devices;
2194                 min_stripes = 2;
2195         }
2196         if (type & (BTRFS_BLOCK_GROUP_DUP)) {
2197                 num_stripes = 2;
2198                 min_stripes = 2;
2199         }
2200         if (type & (BTRFS_BLOCK_GROUP_RAID1)) {
2201                 if (fs_devices->rw_devices < 2)
2202                         return -ENOSPC;
2203                 num_stripes = 2;
2204                 min_stripes = 2;
2205         }
2206         if (type & (BTRFS_BLOCK_GROUP_RAID10)) {
2207                 num_stripes = fs_devices->rw_devices;
2208                 if (num_stripes < 4)
2209                         return -ENOSPC;
2210                 num_stripes &= ~(u32)1;
2211                 sub_stripes = 2;
2212                 min_stripes = 4;
2213         }
2214
2215         if (type & BTRFS_BLOCK_GROUP_DATA) {
2216                 max_chunk_size = 10 * calc_size;
2217                 min_stripe_size = 64 * 1024 * 1024;
2218         } else if (type & BTRFS_BLOCK_GROUP_METADATA) {
2219                 max_chunk_size = 256 * 1024 * 1024;
2220                 min_stripe_size = 32 * 1024 * 1024;
2221         } else if (type & BTRFS_BLOCK_GROUP_SYSTEM) {
2222                 calc_size = 8 * 1024 * 1024;
2223                 max_chunk_size = calc_size * 2;
2224                 min_stripe_size = 1 * 1024 * 1024;
2225         }
2226
2227         /* we don't want a chunk larger than 10% of writeable space */
2228         max_chunk_size = min(div_factor(fs_devices->total_rw_bytes, 1),
2229                              max_chunk_size);
2230
2231 again:
2232         max_avail = 0;
2233         if (!map || map->num_stripes != num_stripes) {
2234                 kfree(map);
2235                 map = kmalloc(map_lookup_size(num_stripes), GFP_NOFS);
2236                 if (!map)
2237                         return -ENOMEM;
2238                 map->num_stripes = num_stripes;
2239         }
2240
2241         if (calc_size * num_stripes > max_chunk_size) {
2242                 calc_size = max_chunk_size;
2243                 do_div(calc_size, num_stripes);
2244                 do_div(calc_size, stripe_len);
2245                 calc_size *= stripe_len;
2246         }
2247
2248         /* we don't want tiny stripes */
2249         if (!looped)
2250                 calc_size = max_t(u64, min_stripe_size, calc_size);
2251
2252         /*
2253          * we're about to do_div by the stripe_len so lets make sure
2254          * we end up with something bigger than a stripe
2255          */
2256         calc_size = max_t(u64, calc_size, stripe_len * 4);
2257
2258         do_div(calc_size, stripe_len);
2259         calc_size *= stripe_len;
2260
2261         cur = fs_devices->alloc_list.next;
2262         index = 0;
2263
2264         if (type & BTRFS_BLOCK_GROUP_DUP)
2265                 min_free = calc_size * 2;
2266         else
2267                 min_free = calc_size;
2268
2269         /*
2270          * we add 1MB because we never use the first 1MB of the device, unless
2271          * we've looped, then we are likely allocating the maximum amount of
2272          * space left already
2273          */
2274         if (!looped)
2275                 min_free += 1024 * 1024;
2276
2277         INIT_LIST_HEAD(&private_devs);
2278         while (index < num_stripes) {
2279                 device = list_entry(cur, struct btrfs_device, dev_alloc_list);
2280                 BUG_ON(!device->writeable);
2281                 if (device->total_bytes > device->bytes_used)
2282                         avail = device->total_bytes - device->bytes_used;
2283                 else
2284                         avail = 0;
2285                 cur = cur->next;
2286
2287                 if (device->in_fs_metadata && avail >= min_free) {
2288                         ret = find_free_dev_extent(trans, device,
2289                                                    min_free, &dev_offset,
2290                                                    &max_avail);
2291                         if (ret == 0) {
2292                                 list_move_tail(&device->dev_alloc_list,
2293                                                &private_devs);
2294                                 map->stripes[index].dev = device;
2295                                 map->stripes[index].physical = dev_offset;
2296                                 index++;
2297                                 if (type & BTRFS_BLOCK_GROUP_DUP) {
2298                                         map->stripes[index].dev = device;
2299                                         map->stripes[index].physical =
2300                                                 dev_offset + calc_size;
2301                                         index++;
2302                                 }
2303                         }
2304                 } else if (device->in_fs_metadata && avail > max_avail)
2305                         max_avail = avail;
2306                 if (cur == &fs_devices->alloc_list)
2307                         break;
2308         }
2309         list_splice(&private_devs, &fs_devices->alloc_list);
2310         if (index < num_stripes) {
2311                 if (index >= min_stripes) {
2312                         num_stripes = index;
2313                         if (type & (BTRFS_BLOCK_GROUP_RAID10)) {
2314                                 num_stripes /= sub_stripes;
2315                                 num_stripes *= sub_stripes;
2316                         }
2317                         looped = 1;
2318                         goto again;
2319                 }
2320                 if (!looped && max_avail > 0) {
2321                         looped = 1;
2322                         calc_size = max_avail;
2323                         goto again;
2324                 }
2325                 kfree(map);
2326                 return -ENOSPC;
2327         }
2328         map->sector_size = extent_root->sectorsize;
2329         map->stripe_len = stripe_len;
2330         map->io_align = stripe_len;
2331         map->io_width = stripe_len;
2332         map->type = type;
2333         map->num_stripes = num_stripes;
2334         map->sub_stripes = sub_stripes;
2335
2336         *map_ret = map;
2337         *stripe_size = calc_size;
2338         *num_bytes = chunk_bytes_by_type(type, calc_size,
2339                                          num_stripes, sub_stripes);
2340
2341         em = alloc_extent_map(GFP_NOFS);
2342         if (!em) {
2343                 kfree(map);
2344                 return -ENOMEM;
2345         }
2346         em->bdev = (struct block_device *)map;
2347         em->start = start;
2348         em->len = *num_bytes;
2349         em->block_start = 0;
2350         em->block_len = em->len;
2351
2352         em_tree = &extent_root->fs_info->mapping_tree.map_tree;
2353         write_lock(&em_tree->lock);
2354         ret = add_extent_mapping(em_tree, em);
2355         write_unlock(&em_tree->lock);
2356         BUG_ON(ret);
2357         free_extent_map(em);
2358
2359         ret = btrfs_make_block_group(trans, extent_root, 0, type,
2360                                      BTRFS_FIRST_CHUNK_TREE_OBJECTID,
2361                                      start, *num_bytes);
2362         BUG_ON(ret);
2363
2364         index = 0;
2365         while (index < map->num_stripes) {
2366                 device = map->stripes[index].dev;
2367                 dev_offset = map->stripes[index].physical;
2368
2369                 ret = btrfs_alloc_dev_extent(trans, device,
2370                                 info->chunk_root->root_key.objectid,
2371                                 BTRFS_FIRST_CHUNK_TREE_OBJECTID,
2372                                 start, dev_offset, calc_size);
2373                 BUG_ON(ret);
2374                 index++;
2375         }
2376
2377         return 0;
2378 }
2379
2380 static int __finish_chunk_alloc(struct btrfs_trans_handle *trans,
2381                                 struct btrfs_root *extent_root,
2382                                 struct map_lookup *map, u64 chunk_offset,
2383                                 u64 chunk_size, u64 stripe_size)
2384 {
2385         u64 dev_offset;
2386         struct btrfs_key key;
2387         struct btrfs_root *chunk_root = extent_root->fs_info->chunk_root;
2388         struct btrfs_device *device;
2389         struct btrfs_chunk *chunk;
2390         struct btrfs_stripe *stripe;
2391         size_t item_size = btrfs_chunk_item_size(map->num_stripes);
2392         int index = 0;
2393         int ret;
2394
2395         chunk = kzalloc(item_size, GFP_NOFS);
2396         if (!chunk)
2397                 return -ENOMEM;
2398
2399         index = 0;
2400         while (index < map->num_stripes) {
2401                 device = map->stripes[index].dev;
2402                 device->bytes_used += stripe_size;
2403                 ret = btrfs_update_device(trans, device);
2404                 BUG_ON(ret);
2405                 index++;
2406         }
2407
2408         index = 0;
2409         stripe = &chunk->stripe;
2410         while (index < map->num_stripes) {
2411                 device = map->stripes[index].dev;
2412                 dev_offset = map->stripes[index].physical;
2413
2414                 btrfs_set_stack_stripe_devid(stripe, device->devid);
2415                 btrfs_set_stack_stripe_offset(stripe, dev_offset);
2416                 memcpy(stripe->dev_uuid, device->uuid, BTRFS_UUID_SIZE);
2417                 stripe++;
2418                 index++;
2419         }
2420
2421         btrfs_set_stack_chunk_length(chunk, chunk_size);
2422         btrfs_set_stack_chunk_owner(chunk, extent_root->root_key.objectid);
2423         btrfs_set_stack_chunk_stripe_len(chunk, map->stripe_len);
2424         btrfs_set_stack_chunk_type(chunk, map->type);
2425         btrfs_set_stack_chunk_num_stripes(chunk, map->num_stripes);
2426         btrfs_set_stack_chunk_io_align(chunk, map->stripe_len);
2427         btrfs_set_stack_chunk_io_width(chunk, map->stripe_len);
2428         btrfs_set_stack_chunk_sector_size(chunk, extent_root->sectorsize);
2429         btrfs_set_stack_chunk_sub_stripes(chunk, map->sub_stripes);
2430
2431         key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
2432         key.type = BTRFS_CHUNK_ITEM_KEY;
2433         key.offset = chunk_offset;
2434
2435         ret = btrfs_insert_item(trans, chunk_root, &key, chunk, item_size);
2436         BUG_ON(ret);
2437
2438         if (map->type & BTRFS_BLOCK_GROUP_SYSTEM) {
2439                 ret = btrfs_add_system_chunk(trans, chunk_root, &key, chunk,
2440                                              item_size);
2441                 BUG_ON(ret);
2442         }
2443         kfree(chunk);
2444         return 0;
2445 }
2446
2447 /*
2448  * Chunk allocation falls into two parts. The first part does works
2449  * that make the new allocated chunk useable, but not do any operation
2450  * that modifies the chunk tree. The second part does the works that
2451  * require modifying the chunk tree. This division is important for the
2452  * bootstrap process of adding storage to a seed btrfs.
2453  */
2454 int btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
2455                       struct btrfs_root *extent_root, u64 type)
2456 {
2457         u64 chunk_offset;
2458         u64 chunk_size;
2459         u64 stripe_size;
2460         struct map_lookup *map;
2461         struct btrfs_root *chunk_root = extent_root->fs_info->chunk_root;
2462         int ret;
2463
2464         ret = find_next_chunk(chunk_root, BTRFS_FIRST_CHUNK_TREE_OBJECTID,
2465                               &chunk_offset);
2466         if (ret)
2467                 return ret;
2468
2469         ret = __btrfs_alloc_chunk(trans, extent_root, &map, &chunk_size,
2470                                   &stripe_size, chunk_offset, type);
2471         if (ret)
2472                 return ret;
2473
2474         ret = __finish_chunk_alloc(trans, extent_root, map, chunk_offset,
2475                                    chunk_size, stripe_size);
2476         BUG_ON(ret);
2477         return 0;
2478 }
2479
2480 static noinline int init_first_rw_device(struct btrfs_trans_handle *trans,
2481                                          struct btrfs_root *root,
2482                                          struct btrfs_device *device)
2483 {
2484         u64 chunk_offset;
2485         u64 sys_chunk_offset;
2486         u64 chunk_size;
2487         u64 sys_chunk_size;
2488         u64 stripe_size;
2489         u64 sys_stripe_size;
2490         u64 alloc_profile;
2491         struct map_lookup *map;
2492         struct map_lookup *sys_map;
2493         struct btrfs_fs_info *fs_info = root->fs_info;
2494         struct btrfs_root *extent_root = fs_info->extent_root;
2495         int ret;
2496
2497         ret = find_next_chunk(fs_info->chunk_root,
2498                               BTRFS_FIRST_CHUNK_TREE_OBJECTID, &chunk_offset);
2499         BUG_ON(ret);
2500
2501         alloc_profile = BTRFS_BLOCK_GROUP_METADATA |
2502                         (fs_info->metadata_alloc_profile &
2503                          fs_info->avail_metadata_alloc_bits);
2504         alloc_profile = btrfs_reduce_alloc_profile(root, alloc_profile);
2505
2506         ret = __btrfs_alloc_chunk(trans, extent_root, &map, &chunk_size,
2507                                   &stripe_size, chunk_offset, alloc_profile);
2508         BUG_ON(ret);
2509
2510         sys_chunk_offset = chunk_offset + chunk_size;
2511
2512         alloc_profile = BTRFS_BLOCK_GROUP_SYSTEM |
2513                         (fs_info->system_alloc_profile &
2514                          fs_info->avail_system_alloc_bits);
2515         alloc_profile = btrfs_reduce_alloc_profile(root, alloc_profile);
2516
2517         ret = __btrfs_alloc_chunk(trans, extent_root, &sys_map,
2518                                   &sys_chunk_size, &sys_stripe_size,
2519                                   sys_chunk_offset, alloc_profile);
2520         BUG_ON(ret);
2521
2522         ret = btrfs_add_device(trans, fs_info->chunk_root, device);
2523         BUG_ON(ret);
2524
2525         /*
2526          * Modifying chunk tree needs allocating new blocks from both
2527          * system block group and metadata block group. So we only can
2528          * do operations require modifying the chunk tree after both
2529          * block groups were created.
2530          */
2531         ret = __finish_chunk_alloc(trans, extent_root, map, chunk_offset,
2532                                    chunk_size, stripe_size);
2533         BUG_ON(ret);
2534
2535         ret = __finish_chunk_alloc(trans, extent_root, sys_map,
2536                                    sys_chunk_offset, sys_chunk_size,
2537                                    sys_stripe_size);
2538         BUG_ON(ret);
2539         return 0;
2540 }
2541
2542 int btrfs_chunk_readonly(struct btrfs_root *root, u64 chunk_offset)
2543 {
2544         struct extent_map *em;
2545         struct map_lookup *map;
2546         struct btrfs_mapping_tree *map_tree = &root->fs_info->mapping_tree;
2547         int readonly = 0;
2548         int i;
2549
2550         read_lock(&map_tree->map_tree.lock);
2551         em = lookup_extent_mapping(&map_tree->map_tree, chunk_offset, 1);
2552         read_unlock(&map_tree->map_tree.lock);
2553         if (!em)
2554                 return 1;
2555
2556         if (btrfs_test_opt(root, DEGRADED)) {
2557                 free_extent_map(em);
2558                 return 0;
2559         }
2560
2561         map = (struct map_lookup *)em->bdev;
2562         for (i = 0; i < map->num_stripes; i++) {
2563                 if (!map->stripes[i].dev->writeable) {
2564                         readonly = 1;
2565                         break;
2566                 }
2567         }
2568         free_extent_map(em);
2569         return readonly;
2570 }
2571
2572 void btrfs_mapping_init(struct btrfs_mapping_tree *tree)
2573 {
2574         extent_map_tree_init(&tree->map_tree, GFP_NOFS);
2575 }
2576
2577 void btrfs_mapping_tree_free(struct btrfs_mapping_tree *tree)
2578 {
2579         struct extent_map *em;
2580
2581         while (1) {
2582                 write_lock(&tree->map_tree.lock);
2583                 em = lookup_extent_mapping(&tree->map_tree, 0, (u64)-1);
2584                 if (em)
2585                         remove_extent_mapping(&tree->map_tree, em);
2586                 write_unlock(&tree->map_tree.lock);
2587                 if (!em)
2588                         break;
2589                 kfree(em->bdev);
2590                 /* once for us */
2591                 free_extent_map(em);
2592                 /* once for the tree */
2593                 free_extent_map(em);
2594         }
2595 }
2596
2597 int btrfs_num_copies(struct btrfs_mapping_tree *map_tree, u64 logical, u64 len)
2598 {
2599         struct extent_map *em;
2600         struct map_lookup *map;
2601         struct extent_map_tree *em_tree = &map_tree->map_tree;
2602         int ret;
2603
2604         read_lock(&em_tree->lock);
2605         em = lookup_extent_mapping(em_tree, logical, len);
2606         read_unlock(&em_tree->lock);
2607         BUG_ON(!em);
2608
2609         BUG_ON(em->start > logical || em->start + em->len < logical);
2610         map = (struct map_lookup *)em->bdev;
2611         if (map->type & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1))
2612                 ret = map->num_stripes;
2613         else if (map->type & BTRFS_BLOCK_GROUP_RAID10)
2614                 ret = map->sub_stripes;
2615         else
2616                 ret = 1;
2617         free_extent_map(em);
2618         return ret;
2619 }
2620
2621 static int find_live_mirror(struct map_lookup *map, int first, int num,
2622                             int optimal)
2623 {
2624         int i;
2625         if (map->stripes[optimal].dev->bdev)
2626                 return optimal;
2627         for (i = first; i < first + num; i++) {
2628                 if (map->stripes[i].dev->bdev)
2629                         return i;
2630         }
2631         /* we couldn't find one that doesn't fail.  Just return something
2632          * and the io error handling code will clean up eventually
2633          */
2634         return optimal;
2635 }
2636
2637 static int __btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw,
2638                              u64 logical, u64 *length,
2639                              struct btrfs_multi_bio **multi_ret,
2640                              int mirror_num, struct page *unplug_page)
2641 {
2642         struct extent_map *em;
2643         struct map_lookup *map;
2644         struct extent_map_tree *em_tree = &map_tree->map_tree;
2645         u64 offset;
2646         u64 stripe_offset;
2647         u64 stripe_nr;
2648         int stripes_allocated = 8;
2649         int stripes_required = 1;
2650         int stripe_index;
2651         int i;
2652         int num_stripes;
2653         int max_errors = 0;
2654         struct btrfs_multi_bio *multi = NULL;
2655
2656         if (multi_ret && !(rw & (1 << BIO_RW)))
2657                 stripes_allocated = 1;
2658 again:
2659         if (multi_ret) {
2660                 multi = kzalloc(btrfs_multi_bio_size(stripes_allocated),
2661                                 GFP_NOFS);
2662                 if (!multi)
2663                         return -ENOMEM;
2664
2665                 atomic_set(&multi->error, 0);
2666         }
2667
2668         read_lock(&em_tree->lock);
2669         em = lookup_extent_mapping(em_tree, logical, *length);
2670         read_unlock(&em_tree->lock);
2671
2672         if (!em && unplug_page) {
2673                 kfree(multi);
2674                 return 0;
2675         }
2676
2677         if (!em) {
2678                 printk(KERN_CRIT "unable to find logical %llu len %llu\n",
2679                        (unsigned long long)logical,
2680                        (unsigned long long)*length);
2681                 BUG();
2682         }
2683
2684         BUG_ON(em->start > logical || em->start + em->len < logical);
2685         map = (struct map_lookup *)em->bdev;
2686         offset = logical - em->start;
2687
2688         if (mirror_num > map->num_stripes)
2689                 mirror_num = 0;
2690
2691         /* if our multi bio struct is too small, back off and try again */
2692         if (rw & (1 << BIO_RW)) {
2693                 if (map->type & (BTRFS_BLOCK_GROUP_RAID1 |
2694                                  BTRFS_BLOCK_GROUP_DUP)) {
2695                         stripes_required = map->num_stripes;
2696                         max_errors = 1;
2697                 } else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
2698                         stripes_required = map->sub_stripes;
2699                         max_errors = 1;
2700                 }
2701         }
2702         if (multi_ret && (rw & (1 << BIO_RW)) &&
2703             stripes_allocated < stripes_required) {
2704                 stripes_allocated = map->num_stripes;
2705                 free_extent_map(em);
2706                 kfree(multi);
2707                 goto again;
2708         }
2709         stripe_nr = offset;
2710         /*
2711          * stripe_nr counts the total number of stripes we have to stride
2712          * to get to this block
2713          */
2714         do_div(stripe_nr, map->stripe_len);
2715
2716         stripe_offset = stripe_nr * map->stripe_len;
2717         BUG_ON(offset < stripe_offset);
2718
2719         /* stripe_offset is the offset of this block in its stripe*/
2720         stripe_offset = offset - stripe_offset;
2721
2722         if (map->type & (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID1 |
2723                          BTRFS_BLOCK_GROUP_RAID10 |
2724                          BTRFS_BLOCK_GROUP_DUP)) {
2725                 /* we limit the length of each bio to what fits in a stripe */
2726                 *length = min_t(u64, em->len - offset,
2727                               map->stripe_len - stripe_offset);
2728         } else {
2729                 *length = em->len - offset;
2730         }
2731
2732         if (!multi_ret && !unplug_page)
2733                 goto out;
2734
2735         num_stripes = 1;
2736         stripe_index = 0;
2737         if (map->type & BTRFS_BLOCK_GROUP_RAID1) {
2738                 if (unplug_page || (rw & (1 << BIO_RW)))
2739                         num_stripes = map->num_stripes;
2740                 else if (mirror_num)
2741                         stripe_index = mirror_num - 1;
2742                 else {
2743                         stripe_index = find_live_mirror(map, 0,
2744                                             map->num_stripes,
2745                                             current->pid % map->num_stripes);
2746                 }
2747
2748         } else if (map->type & BTRFS_BLOCK_GROUP_DUP) {
2749                 if (rw & (1 << BIO_RW))
2750                         num_stripes = map->num_stripes;
2751                 else if (mirror_num)
2752                         stripe_index = mirror_num - 1;
2753
2754         } else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
2755                 int factor = map->num_stripes / map->sub_stripes;
2756
2757                 stripe_index = do_div(stripe_nr, factor);
2758                 stripe_index *= map->sub_stripes;
2759
2760                 if (unplug_page || (rw & (1 << BIO_RW)))
2761                         num_stripes = map->sub_stripes;
2762                 else if (mirror_num)
2763                         stripe_index += mirror_num - 1;
2764                 else {
2765                         stripe_index = find_live_mirror(map, stripe_index,
2766                                               map->sub_stripes, stripe_index +
2767                                               current->pid % map->sub_stripes);
2768                 }
2769         } else {
2770                 /*
2771                  * after this do_div call, stripe_nr is the number of stripes
2772                  * on this device we have to walk to find the data, and
2773                  * stripe_index is the number of our device in the stripe array
2774                  */
2775                 stripe_index = do_div(stripe_nr, map->num_stripes);
2776         }
2777         BUG_ON(stripe_index >= map->num_stripes);
2778
2779         for (i = 0; i < num_stripes; i++) {
2780                 if (unplug_page) {
2781                         struct btrfs_device *device;
2782                         struct backing_dev_info *bdi;
2783
2784                         device = map->stripes[stripe_index].dev;
2785                         if (device->bdev) {
2786                                 bdi = blk_get_backing_dev_info(device->bdev);
2787                                 if (bdi->unplug_io_fn)
2788                                         bdi->unplug_io_fn(bdi, unplug_page);
2789                         }
2790                 } else {
2791                         multi->stripes[i].physical =
2792                                 map->stripes[stripe_index].physical +
2793                                 stripe_offset + stripe_nr * map->stripe_len;
2794                         multi->stripes[i].dev = map->stripes[stripe_index].dev;
2795                 }
2796                 stripe_index++;
2797         }
2798         if (multi_ret) {
2799                 *multi_ret = multi;
2800                 multi->num_stripes = num_stripes;
2801                 multi->max_errors = max_errors;
2802         }
2803 out:
2804         free_extent_map(em);
2805         return 0;
2806 }
2807
2808 int btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw,
2809                       u64 logical, u64 *length,
2810                       struct btrfs_multi_bio **multi_ret, int mirror_num)
2811 {
2812         return __btrfs_map_block(map_tree, rw, logical, length, multi_ret,
2813                                  mirror_num, NULL);
2814 }
2815
2816 int btrfs_rmap_block(struct btrfs_mapping_tree *map_tree,
2817                      u64 chunk_start, u64 physical, u64 devid,
2818                      u64 **logical, int *naddrs, int *stripe_len)
2819 {
2820         struct extent_map_tree *em_tree = &map_tree->map_tree;
2821         struct extent_map *em;
2822         struct map_lookup *map;
2823         u64 *buf;
2824         u64 bytenr;
2825         u64 length;
2826         u64 stripe_nr;
2827         int i, j, nr = 0;
2828
2829         read_lock(&em_tree->lock);
2830         em = lookup_extent_mapping(em_tree, chunk_start, 1);
2831         read_unlock(&em_tree->lock);
2832
2833         BUG_ON(!em || em->start != chunk_start);
2834         map = (struct map_lookup *)em->bdev;
2835
2836         length = em->len;
2837         if (map->type & BTRFS_BLOCK_GROUP_RAID10)
2838                 do_div(length, map->num_stripes / map->sub_stripes);
2839         else if (map->type & BTRFS_BLOCK_GROUP_RAID0)
2840                 do_div(length, map->num_stripes);
2841
2842         buf = kzalloc(sizeof(u64) * map->num_stripes, GFP_NOFS);
2843         BUG_ON(!buf);
2844
2845         for (i = 0; i < map->num_stripes; i++) {
2846                 if (devid && map->stripes[i].dev->devid != devid)
2847                         continue;
2848                 if (map->stripes[i].physical > physical ||
2849                     map->stripes[i].physical + length <= physical)
2850                         continue;
2851
2852                 stripe_nr = physical - map->stripes[i].physical;
2853                 do_div(stripe_nr, map->stripe_len);
2854
2855                 if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
2856                         stripe_nr = stripe_nr * map->num_stripes + i;
2857                         do_div(stripe_nr, map->sub_stripes);
2858                 } else if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
2859                         stripe_nr = stripe_nr * map->num_stripes + i;
2860                 }
2861                 bytenr = chunk_start + stripe_nr * map->stripe_len;
2862                 WARN_ON(nr >= map->num_stripes);
2863                 for (j = 0; j < nr; j++) {
2864                         if (buf[j] == bytenr)
2865                                 break;
2866                 }
2867                 if (j == nr) {
2868                         WARN_ON(nr >= map->num_stripes);
2869                         buf[nr++] = bytenr;
2870                 }
2871         }
2872
2873         *logical = buf;
2874         *naddrs = nr;
2875         *stripe_len = map->stripe_len;
2876
2877         free_extent_map(em);
2878         return 0;
2879 }
2880
2881 int btrfs_unplug_page(struct btrfs_mapping_tree *map_tree,
2882                       u64 logical, struct page *page)
2883 {
2884         u64 length = PAGE_CACHE_SIZE;
2885         return __btrfs_map_block(map_tree, READ, logical, &length,
2886                                  NULL, 0, page);
2887 }
2888
2889 static void end_bio_multi_stripe(struct bio *bio, int err)
2890 {
2891         struct btrfs_multi_bio *multi = bio->bi_private;
2892         int is_orig_bio = 0;
2893
2894         if (err)
2895                 atomic_inc(&multi->error);
2896
2897         if (bio == multi->orig_bio)
2898                 is_orig_bio = 1;
2899
2900         if (atomic_dec_and_test(&multi->stripes_pending)) {
2901                 if (!is_orig_bio) {
2902                         bio_put(bio);
2903                         bio = multi->orig_bio;
2904                 }
2905                 bio->bi_private = multi->private;
2906                 bio->bi_end_io = multi->end_io;
2907                 /* only send an error to the higher layers if it is
2908                  * beyond the tolerance of the multi-bio
2909                  */
2910                 if (atomic_read(&multi->error) > multi->max_errors) {
2911                         err = -EIO;
2912                 } else if (err) {
2913                         /*
2914                          * this bio is actually up to date, we didn't
2915                          * go over the max number of errors
2916                          */
2917                         set_bit(BIO_UPTODATE, &bio->bi_flags);
2918                         err = 0;
2919                 }
2920                 kfree(multi);
2921
2922                 bio_endio(bio, err);
2923         } else if (!is_orig_bio) {
2924                 bio_put(bio);
2925         }
2926 }
2927
2928 struct async_sched {
2929         struct bio *bio;
2930         int rw;
2931         struct btrfs_fs_info *info;
2932         struct btrfs_work work;
2933 };
2934
2935 /*
2936  * see run_scheduled_bios for a description of why bios are collected for
2937  * async submit.
2938  *
2939  * This will add one bio to the pending list for a device and make sure
2940  * the work struct is scheduled.
2941  */
2942 static noinline int schedule_bio(struct btrfs_root *root,
2943                                  struct btrfs_device *device,
2944                                  int rw, struct bio *bio)
2945 {
2946         int should_queue = 1;
2947         struct btrfs_pending_bios *pending_bios;
2948
2949         /* don't bother with additional async steps for reads, right now */
2950         if (!(rw & (1 << BIO_RW))) {
2951                 bio_get(bio);
2952                 submit_bio(rw, bio);
2953                 bio_put(bio);
2954                 return 0;
2955         }
2956
2957         /*
2958          * nr_async_bios allows us to reliably return congestion to the
2959          * higher layers.  Otherwise, the async bio makes it appear we have
2960          * made progress against dirty pages when we've really just put it
2961          * on a queue for later
2962          */
2963         atomic_inc(&root->fs_info->nr_async_bios);
2964         WARN_ON(bio->bi_next);
2965         bio->bi_next = NULL;
2966         bio->bi_rw |= rw;
2967
2968         spin_lock(&device->io_lock);
2969         if (bio_rw_flagged(bio, BIO_RW_SYNCIO))
2970                 pending_bios = &device->pending_sync_bios;
2971         else
2972                 pending_bios = &device->pending_bios;
2973
2974         if (pending_bios->tail)
2975                 pending_bios->tail->bi_next = bio;
2976
2977         pending_bios->tail = bio;
2978         if (!pending_bios->head)
2979                 pending_bios->head = bio;
2980         if (device->running_pending)
2981                 should_queue = 0;
2982
2983         spin_unlock(&device->io_lock);
2984
2985         if (should_queue)
2986                 btrfs_queue_worker(&root->fs_info->submit_workers,
2987                                    &device->work);
2988         return 0;
2989 }
2990
2991 int btrfs_map_bio(struct btrfs_root *root, int rw, struct bio *bio,
2992                   int mirror_num, int async_submit)
2993 {
2994         struct btrfs_mapping_tree *map_tree;
2995         struct btrfs_device *dev;
2996         struct bio *first_bio = bio;
2997         u64 logical = (u64)bio->bi_sector << 9;
2998         u64 length = 0;
2999         u64 map_length;
3000         struct btrfs_multi_bio *multi = NULL;
3001         int ret;
3002         int dev_nr = 0;
3003         int total_devs = 1;
3004
3005         length = bio->bi_size;
3006         map_tree = &root->fs_info->mapping_tree;
3007         map_length = length;
3008
3009         ret = btrfs_map_block(map_tree, rw, logical, &map_length, &multi,
3010                               mirror_num);
3011         BUG_ON(ret);
3012
3013         total_devs = multi->num_stripes;
3014         if (map_length < length) {
3015                 printk(KERN_CRIT "mapping failed logical %llu bio len %llu "
3016                        "len %llu\n", (unsigned long long)logical,
3017                        (unsigned long long)length,
3018                        (unsigned long long)map_length);
3019                 BUG();
3020         }
3021         multi->end_io = first_bio->bi_end_io;
3022         multi->private = first_bio->bi_private;
3023         multi->orig_bio = first_bio;
3024         atomic_set(&multi->stripes_pending, multi->num_stripes);
3025
3026         while (dev_nr < total_devs) {
3027                 if (total_devs > 1) {
3028                         if (dev_nr < total_devs - 1) {
3029                                 bio = bio_clone(first_bio, GFP_NOFS);
3030                                 BUG_ON(!bio);
3031                         } else {
3032                                 bio = first_bio;
3033                         }
3034                         bio->bi_private = multi;
3035                         bio->bi_end_io = end_bio_multi_stripe;
3036                 }
3037                 bio->bi_sector = multi->stripes[dev_nr].physical >> 9;
3038                 dev = multi->stripes[dev_nr].dev;
3039                 BUG_ON(rw == WRITE && !dev->writeable);
3040                 if (dev && dev->bdev) {
3041                         bio->bi_bdev = dev->bdev;
3042                         if (async_submit)
3043                                 schedule_bio(root, dev, rw, bio);
3044                         else
3045                                 submit_bio(rw, bio);
3046                 } else {
3047                         bio->bi_bdev = root->fs_info->fs_devices->latest_bdev;
3048                         bio->bi_sector = logical >> 9;
3049                         bio_endio(bio, -EIO);
3050                 }
3051                 dev_nr++;
3052         }
3053         if (total_devs == 1)
3054                 kfree(multi);
3055         return 0;
3056 }
3057
3058 struct btrfs_device *btrfs_find_device(struct btrfs_root *root, u64 devid,
3059                                        u8 *uuid, u8 *fsid)
3060 {
3061         struct btrfs_device *device;
3062         struct btrfs_fs_devices *cur_devices;
3063
3064         cur_devices = root->fs_info->fs_devices;
3065         while (cur_devices) {
3066                 if (!fsid ||
3067                     !memcmp(cur_devices->fsid, fsid, BTRFS_UUID_SIZE)) {
3068                         device = __find_device(&cur_devices->devices,
3069                                                devid, uuid);
3070                         if (device)
3071                                 return device;
3072                 }
3073                 cur_devices = cur_devices->seed;
3074         }
3075         return NULL;
3076 }
3077
3078 static struct btrfs_device *add_missing_dev(struct btrfs_root *root,
3079                                             u64 devid, u8 *dev_uuid)
3080 {
3081         struct btrfs_device *device;
3082         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
3083
3084         device = kzalloc(sizeof(*device), GFP_NOFS);
3085         if (!device)
3086                 return NULL;
3087         list_add(&device->dev_list,
3088                  &fs_devices->devices);
3089         device->barriers = 1;
3090         device->dev_root = root->fs_info->dev_root;
3091         device->devid = devid;
3092         device->work.func = pending_bios_fn;
3093         device->fs_devices = fs_devices;
3094         fs_devices->num_devices++;
3095         spin_lock_init(&device->io_lock);
3096         INIT_LIST_HEAD(&device->dev_alloc_list);
3097         memcpy(device->uuid, dev_uuid, BTRFS_UUID_SIZE);
3098         return device;
3099 }
3100
3101 static int read_one_chunk(struct btrfs_root *root, struct btrfs_key *key,
3102                           struct extent_buffer *leaf,
3103                           struct btrfs_chunk *chunk)
3104 {
3105         struct btrfs_mapping_tree *map_tree = &root->fs_info->mapping_tree;
3106         struct map_lookup *map;
3107         struct extent_map *em;
3108         u64 logical;
3109         u64 length;
3110         u64 devid;
3111         u8 uuid[BTRFS_UUID_SIZE];
3112         int num_stripes;
3113         int ret;
3114         int i;
3115
3116         logical = key->offset;
3117         length = btrfs_chunk_length(leaf, chunk);
3118
3119         read_lock(&map_tree->map_tree.lock);
3120         em = lookup_extent_mapping(&map_tree->map_tree, logical, 1);
3121         read_unlock(&map_tree->map_tree.lock);
3122
3123         /* already mapped? */
3124         if (em && em->start <= logical && em->start + em->len > logical) {
3125                 free_extent_map(em);
3126                 return 0;
3127         } else if (em) {
3128                 free_extent_map(em);
3129         }
3130
3131         em = alloc_extent_map(GFP_NOFS);
3132         if (!em)
3133                 return -ENOMEM;
3134         num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
3135         map = kmalloc(map_lookup_size(num_stripes), GFP_NOFS);
3136         if (!map) {
3137                 free_extent_map(em);
3138                 return -ENOMEM;
3139         }
3140
3141         em->bdev = (struct block_device *)map;
3142         em->start = logical;
3143         em->len = length;
3144         em->block_start = 0;
3145         em->block_len = em->len;
3146
3147         map->num_stripes = num_stripes;
3148         map->io_width = btrfs_chunk_io_width(leaf, chunk);
3149         map->io_align = btrfs_chunk_io_align(leaf, chunk);
3150         map->sector_size = btrfs_chunk_sector_size(leaf, chunk);
3151         map->stripe_len = btrfs_chunk_stripe_len(leaf, chunk);
3152         map->type = btrfs_chunk_type(leaf, chunk);
3153         map->sub_stripes = btrfs_chunk_sub_stripes(leaf, chunk);
3154         for (i = 0; i < num_stripes; i++) {
3155                 map->stripes[i].physical =
3156                         btrfs_stripe_offset_nr(leaf, chunk, i);
3157                 devid = btrfs_stripe_devid_nr(leaf, chunk, i);
3158                 read_extent_buffer(leaf, uuid, (unsigned long)
3159                                    btrfs_stripe_dev_uuid_nr(chunk, i),
3160                                    BTRFS_UUID_SIZE);
3161                 map->stripes[i].dev = btrfs_find_device(root, devid, uuid,
3162                                                         NULL);
3163                 if (!map->stripes[i].dev && !btrfs_test_opt(root, DEGRADED)) {
3164                         kfree(map);
3165                         free_extent_map(em);
3166                         return -EIO;
3167                 }
3168                 if (!map->stripes[i].dev) {
3169                         map->stripes[i].dev =
3170                                 add_missing_dev(root, devid, uuid);
3171                         if (!map->stripes[i].dev) {
3172                                 kfree(map);
3173                                 free_extent_map(em);
3174                                 return -EIO;
3175                         }
3176                 }
3177                 map->stripes[i].dev->in_fs_metadata = 1;
3178         }
3179
3180         write_lock(&map_tree->map_tree.lock);
3181         ret = add_extent_mapping(&map_tree->map_tree, em);
3182         write_unlock(&map_tree->map_tree.lock);
3183         BUG_ON(ret);
3184         free_extent_map(em);
3185
3186         return 0;
3187 }
3188
3189 static int fill_device_from_item(struct extent_buffer *leaf,
3190                                  struct btrfs_dev_item *dev_item,
3191                                  struct btrfs_device *device)
3192 {
3193         unsigned long ptr;
3194
3195         device->devid = btrfs_device_id(leaf, dev_item);
3196         device->disk_total_bytes = btrfs_device_total_bytes(leaf, dev_item);
3197         device->total_bytes = device->disk_total_bytes;
3198         device->bytes_used = btrfs_device_bytes_used(leaf, dev_item);
3199         device->type = btrfs_device_type(leaf, dev_item);
3200         device->io_align = btrfs_device_io_align(leaf, dev_item);
3201         device->io_width = btrfs_device_io_width(leaf, dev_item);
3202         device->sector_size = btrfs_device_sector_size(leaf, dev_item);
3203
3204         ptr = (unsigned long)btrfs_device_uuid(dev_item);
3205         read_extent_buffer(leaf, device->uuid, ptr, BTRFS_UUID_SIZE);
3206
3207         return 0;
3208 }
3209
3210 static int open_seed_devices(struct btrfs_root *root, u8 *fsid)
3211 {
3212         struct btrfs_fs_devices *fs_devices;
3213         int ret;
3214
3215         mutex_lock(&uuid_mutex);
3216
3217         fs_devices = root->fs_info->fs_devices->seed;
3218         while (fs_devices) {
3219                 if (!memcmp(fs_devices->fsid, fsid, BTRFS_UUID_SIZE)) {
3220                         ret = 0;
3221                         goto out;
3222                 }
3223                 fs_devices = fs_devices->seed;
3224         }
3225
3226         fs_devices = find_fsid(fsid);
3227         if (!fs_devices) {
3228                 ret = -ENOENT;
3229                 goto out;
3230         }
3231
3232         fs_devices = clone_fs_devices(fs_devices);
3233         if (IS_ERR(fs_devices)) {
3234                 ret = PTR_ERR(fs_devices);
3235                 goto out;
3236         }
3237
3238         ret = __btrfs_open_devices(fs_devices, FMODE_READ,
3239                                    root->fs_info->bdev_holder);
3240         if (ret)
3241                 goto out;
3242
3243         if (!fs_devices->seeding) {
3244                 __btrfs_close_devices(fs_devices);
3245                 free_fs_devices(fs_devices);
3246                 ret = -EINVAL;
3247                 goto out;
3248         }
3249
3250         fs_devices->seed = root->fs_info->fs_devices->seed;
3251         root->fs_info->fs_devices->seed = fs_devices;
3252 out:
3253         mutex_unlock(&uuid_mutex);
3254         return ret;
3255 }
3256
3257 static int read_one_dev(struct btrfs_root *root,
3258                         struct extent_buffer *leaf,
3259                         struct btrfs_dev_item *dev_item)
3260 {
3261         struct btrfs_device *device;
3262         u64 devid;
3263         int ret;
3264         u8 fs_uuid[BTRFS_UUID_SIZE];
3265         u8 dev_uuid[BTRFS_UUID_SIZE];
3266
3267         devid = btrfs_device_id(leaf, dev_item);
3268         read_extent_buffer(leaf, dev_uuid,
3269                            (unsigned long)btrfs_device_uuid(dev_item),
3270                            BTRFS_UUID_SIZE);
3271         read_extent_buffer(leaf, fs_uuid,
3272                            (unsigned long)btrfs_device_fsid(dev_item),
3273                            BTRFS_UUID_SIZE);
3274
3275         if (memcmp(fs_uuid, root->fs_info->fsid, BTRFS_UUID_SIZE)) {
3276                 ret = open_seed_devices(root, fs_uuid);
3277                 if (ret && !btrfs_test_opt(root, DEGRADED))
3278                         return ret;
3279         }
3280
3281         device = btrfs_find_device(root, devid, dev_uuid, fs_uuid);
3282         if (!device || !device->bdev) {
3283                 if (!btrfs_test_opt(root, DEGRADED))
3284                         return -EIO;
3285
3286                 if (!device) {
3287                         printk(KERN_WARNING "warning devid %llu missing\n",
3288                                (unsigned long long)devid);
3289                         device = add_missing_dev(root, devid, dev_uuid);
3290                         if (!device)
3291                                 return -ENOMEM;
3292                 }
3293         }
3294
3295         if (device->fs_devices != root->fs_info->fs_devices) {
3296                 BUG_ON(device->writeable);
3297                 if (device->generation !=
3298                     btrfs_device_generation(leaf, dev_item))
3299                         return -EINVAL;
3300         }
3301
3302         fill_device_from_item(leaf, dev_item, device);
3303         device->dev_root = root->fs_info->dev_root;
3304         device->in_fs_metadata = 1;
3305         if (device->writeable)
3306                 device->fs_devices->total_rw_bytes += device->total_bytes;
3307         ret = 0;
3308         return ret;
3309 }
3310
3311 int btrfs_read_super_device(struct btrfs_root *root, struct extent_buffer *buf)
3312 {
3313         struct btrfs_dev_item *dev_item;
3314
3315         dev_item = (struct btrfs_dev_item *)offsetof(struct btrfs_super_block,
3316                                                      dev_item);
3317         return read_one_dev(root, buf, dev_item);
3318 }
3319
3320 int btrfs_read_sys_array(struct btrfs_root *root)
3321 {
3322         struct btrfs_super_block *super_copy = &root->fs_info->super_copy;
3323         struct extent_buffer *sb;
3324         struct btrfs_disk_key *disk_key;
3325         struct btrfs_chunk *chunk;
3326         u8 *ptr;
3327         unsigned long sb_ptr;
3328         int ret = 0;
3329         u32 num_stripes;
3330         u32 array_size;
3331         u32 len = 0;
3332         u32 cur;
3333         struct btrfs_key key;
3334
3335         sb = btrfs_find_create_tree_block(root, BTRFS_SUPER_INFO_OFFSET,
3336                                           BTRFS_SUPER_INFO_SIZE);
3337         if (!sb)
3338                 return -ENOMEM;
3339         btrfs_set_buffer_uptodate(sb);
3340         btrfs_set_buffer_lockdep_class(sb, 0);
3341
3342         write_extent_buffer(sb, super_copy, 0, BTRFS_SUPER_INFO_SIZE);
3343         array_size = btrfs_super_sys_array_size(super_copy);
3344
3345         ptr = super_copy->sys_chunk_array;
3346         sb_ptr = offsetof(struct btrfs_super_block, sys_chunk_array);
3347         cur = 0;
3348
3349         while (cur < array_size) {
3350                 disk_key = (struct btrfs_disk_key *)ptr;
3351                 btrfs_disk_key_to_cpu(&key, disk_key);
3352
3353                 len = sizeof(*disk_key); ptr += len;
3354                 sb_ptr += len;
3355                 cur += len;
3356
3357                 if (key.type == BTRFS_CHUNK_ITEM_KEY) {
3358                         chunk = (struct btrfs_chunk *)sb_ptr;
3359                         ret = read_one_chunk(root, &key, sb, chunk);
3360                         if (ret)
3361                                 break;
3362                         num_stripes = btrfs_chunk_num_stripes(sb, chunk);
3363                         len = btrfs_chunk_item_size(num_stripes);
3364                 } else {
3365                         ret = -EIO;
3366                         break;
3367                 }
3368                 ptr += len;
3369                 sb_ptr += len;
3370                 cur += len;
3371         }
3372         free_extent_buffer(sb);
3373         return ret;
3374 }
3375
3376 int btrfs_read_chunk_tree(struct btrfs_root *root)
3377 {
3378         struct btrfs_path *path;
3379         struct extent_buffer *leaf;
3380         struct btrfs_key key;
3381         struct btrfs_key found_key;
3382         int ret;
3383         int slot;
3384
3385         root = root->fs_info->chunk_root;
3386
3387         path = btrfs_alloc_path();
3388         if (!path)
3389                 return -ENOMEM;
3390
3391         /* first we search for all of the device items, and then we
3392          * read in all of the chunk items.  This way we can create chunk
3393          * mappings that reference all of the devices that are afound
3394          */
3395         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
3396         key.offset = 0;
3397         key.type = 0;
3398 again:
3399         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3400         if (ret < 0)
3401                 goto error;
3402         while (1) {
3403                 leaf = path->nodes[0];
3404                 slot = path->slots[0];
3405                 if (slot >= btrfs_header_nritems(leaf)) {
3406                         ret = btrfs_next_leaf(root, path);
3407                         if (ret == 0)
3408                                 continue;
3409                         if (ret < 0)
3410                                 goto error;
3411                         break;
3412                 }
3413                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
3414                 if (key.objectid == BTRFS_DEV_ITEMS_OBJECTID) {
3415                         if (found_key.objectid != BTRFS_DEV_ITEMS_OBJECTID)
3416                                 break;
3417                         if (found_key.type == BTRFS_DEV_ITEM_KEY) {
3418                                 struct btrfs_dev_item *dev_item;
3419                                 dev_item = btrfs_item_ptr(leaf, slot,
3420                                                   struct btrfs_dev_item);
3421                                 ret = read_one_dev(root, leaf, dev_item);
3422                                 if (ret)
3423                                         goto error;
3424                         }
3425                 } else if (found_key.type == BTRFS_CHUNK_ITEM_KEY) {
3426                         struct btrfs_chunk *chunk;
3427                         chunk = btrfs_item_ptr(leaf, slot, struct btrfs_chunk);
3428                         ret = read_one_chunk(root, &found_key, leaf, chunk);
3429                         if (ret)
3430                                 goto error;
3431                 }
3432                 path->slots[0]++;
3433         }
3434         if (key.objectid == BTRFS_DEV_ITEMS_OBJECTID) {
3435                 key.objectid = 0;
3436                 btrfs_release_path(root, path);
3437                 goto again;
3438         }
3439         ret = 0;
3440 error:
3441         btrfs_free_path(path);
3442         return ret;
3443 }