1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * Copyright (C) STRATO AG 2012.  All rights reserved.
   4 */
   5
   6#include <linux/sched.h>
   7#include <linux/bio.h>
   8#include <linux/slab.h>
   9#include <linux/blkdev.h>
  10#include <linux/kthread.h>
  11#include <linux/math64.h>
  12#include "misc.h"
  13#include "ctree.h"
  14#include "extent_map.h"
  15#include "disk-io.h"
  16#include "transaction.h"
  17#include "print-tree.h"
  18#include "volumes.h"
  19#include "async-thread.h"
  20#include "check-integrity.h"
 
  21#include "dev-replace.h"
  22#include "sysfs.h"
  23#include "zoned.h"
  24#include "block-group.h"
  25#include "fs.h"
  26#include "accessors.h"
  27#include "scrub.h"
  28
  29/*
  30 * Device replace overview
  31 *
  32 * [Objective]
  33 * To copy all extents (both new and on-disk) from source device to target
  34 * device, while still keeping the filesystem read-write.
  35 *
  36 * [Method]
  37 * There are two main methods involved:
  38 *
  39 * - Write duplication
  40 *
  41 *   All new writes will be written to both target and source devices, so even
  42 *   if replace gets canceled, sources device still contains up-to-date data.
  43 *
  44 *   Location:		handle_ops_on_dev_replace() from __btrfs_map_block()
  45 *   Start:		btrfs_dev_replace_start()
  46 *   End:		btrfs_dev_replace_finishing()
  47 *   Content:		Latest data/metadata
  48 *
  49 * - Copy existing extents
  50 *
  51 *   This happens by re-using scrub facility, as scrub also iterates through
  52 *   existing extents from commit root.
  53 *
  54 *   Location:		scrub_write_block_to_dev_replace() from
  55 *   			scrub_block_complete()
  56 *   Content:		Data/meta from commit root.
  57 *
  58 * Due to the content difference, we need to avoid nocow write when dev-replace
  59 * is happening.  This is done by marking the block group read-only and waiting
  60 * for NOCOW writes.
  61 *
  62 * After replace is done, the finishing part is done by swapping the target and
  63 * source devices.
  64 *
  65 *   Location:		btrfs_dev_replace_update_device_in_mapping_tree() from
  66 *   			btrfs_dev_replace_finishing()
  67 */
  68
  69static int btrfs_dev_replace_finishing(struct btrfs_fs_info *fs_info,
  70				       int scrub_ret);
 
 
 
 
  71static int btrfs_dev_replace_kthread(void *data);
  72
  73int btrfs_init_dev_replace(struct btrfs_fs_info *fs_info)
  74{
  75	struct btrfs_dev_lookup_args args = { .devid = BTRFS_DEV_REPLACE_DEVID };
  76	struct btrfs_key key;
  77	struct btrfs_root *dev_root = fs_info->dev_root;
  78	struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
  79	struct extent_buffer *eb;
  80	int slot;
  81	int ret = 0;
  82	struct btrfs_path *path = NULL;
  83	int item_size;
  84	struct btrfs_dev_replace_item *ptr;
  85	u64 src_devid;
  86
  87	if (!dev_root)
  88		return 0;
  89
  90	path = btrfs_alloc_path();
  91	if (!path) {
  92		ret = -ENOMEM;
  93		goto out;
  94	}
  95
  96	key.objectid = 0;
  97	key.type = BTRFS_DEV_REPLACE_KEY;
  98	key.offset = 0;
  99	ret = btrfs_search_slot(NULL, dev_root, &key, path, 0, 0);
 100	if (ret) {
 101no_valid_dev_replace_entry_found:
 102		/*
 103		 * We don't have a replace item or it's corrupted.  If there is
 104		 * a replace target, fail the mount.
 105		 */
 106		if (btrfs_find_device(fs_info->fs_devices, &args)) {
 107			btrfs_err(fs_info,
 108			"found replace target device without a valid replace item");
 109			ret = -EUCLEAN;
 110			goto out;
 111		}
 112		ret = 0;
 113		dev_replace->replace_state =
 114			BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED;
 115		dev_replace->cont_reading_from_srcdev_mode =
 116		    BTRFS_DEV_REPLACE_ITEM_CONT_READING_FROM_SRCDEV_MODE_ALWAYS;
 117		dev_replace->time_started = 0;
 118		dev_replace->time_stopped = 0;
 119		atomic64_set(&dev_replace->num_write_errors, 0);
 120		atomic64_set(&dev_replace->num_uncorrectable_read_errors, 0);
 121		dev_replace->cursor_left = 0;
 122		dev_replace->committed_cursor_left = 0;
 123		dev_replace->cursor_left_last_write_of_item = 0;
 124		dev_replace->cursor_right = 0;
 125		dev_replace->srcdev = NULL;
 126		dev_replace->tgtdev = NULL;
 127		dev_replace->is_valid = 0;
 128		dev_replace->item_needs_writeback = 0;
 129		goto out;
 130	}
 131	slot = path->slots[0];
 132	eb = path->nodes[0];
 133	item_size = btrfs_item_size(eb, slot);
 134	ptr = btrfs_item_ptr(eb, slot, struct btrfs_dev_replace_item);
 135
 136	if (item_size != sizeof(struct btrfs_dev_replace_item)) {
 137		btrfs_warn(fs_info,
 138			"dev_replace entry found has unexpected size, ignore entry");
 139		goto no_valid_dev_replace_entry_found;
 140	}
 141
 142	src_devid = btrfs_dev_replace_src_devid(eb, ptr);
 143	dev_replace->cont_reading_from_srcdev_mode =
 144		btrfs_dev_replace_cont_reading_from_srcdev_mode(eb, ptr);
 145	dev_replace->replace_state = btrfs_dev_replace_replace_state(eb, ptr);
 146	dev_replace->time_started = btrfs_dev_replace_time_started(eb, ptr);
 147	dev_replace->time_stopped =
 148		btrfs_dev_replace_time_stopped(eb, ptr);
 149	atomic64_set(&dev_replace->num_write_errors,
 150		     btrfs_dev_replace_num_write_errors(eb, ptr));
 151	atomic64_set(&dev_replace->num_uncorrectable_read_errors,
 152		     btrfs_dev_replace_num_uncorrectable_read_errors(eb, ptr));
 153	dev_replace->cursor_left = btrfs_dev_replace_cursor_left(eb, ptr);
 154	dev_replace->committed_cursor_left = dev_replace->cursor_left;
 155	dev_replace->cursor_left_last_write_of_item = dev_replace->cursor_left;
 156	dev_replace->cursor_right = btrfs_dev_replace_cursor_right(eb, ptr);
 157	dev_replace->is_valid = 1;
 158
 159	dev_replace->item_needs_writeback = 0;
 160	switch (dev_replace->replace_state) {
 161	case BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED:
 162	case BTRFS_IOCTL_DEV_REPLACE_STATE_FINISHED:
 163	case BTRFS_IOCTL_DEV_REPLACE_STATE_CANCELED:
 164		/*
 165		 * We don't have an active replace item but if there is a
 166		 * replace target, fail the mount.
 167		 */
 168		if (btrfs_find_device(fs_info->fs_devices, &args)) {
 169			btrfs_err(fs_info,
 170"replace without active item, run 'device scan --forget' on the target device");
 171			ret = -EUCLEAN;
 172		} else {
 173			dev_replace->srcdev = NULL;
 174			dev_replace->tgtdev = NULL;
 175		}
 176		break;
 177	case BTRFS_IOCTL_DEV_REPLACE_STATE_STARTED:
 178	case BTRFS_IOCTL_DEV_REPLACE_STATE_SUSPENDED:
 179		dev_replace->tgtdev = btrfs_find_device(fs_info->fs_devices, &args);
 180		args.devid = src_devid;
 181		dev_replace->srcdev = btrfs_find_device(fs_info->fs_devices, &args);
 182
 
 183		/*
 184		 * allow 'btrfs dev replace_cancel' if src/tgt device is
 185		 * missing
 186		 */
 187		if (!dev_replace->srcdev &&
 188		    !btrfs_test_opt(fs_info, DEGRADED)) {
 189			ret = -EIO;
 190			btrfs_warn(fs_info,
 191			   "cannot mount because device replace operation is ongoing and");
 192			btrfs_warn(fs_info,
 193			   "srcdev (devid %llu) is missing, need to run 'btrfs dev scan'?",
 194			   src_devid);
 195		}
 196		if (!dev_replace->tgtdev &&
 197		    !btrfs_test_opt(fs_info, DEGRADED)) {
 198			ret = -EIO;
 199			btrfs_warn(fs_info,
 200			   "cannot mount because device replace operation is ongoing and");
 201			btrfs_warn(fs_info,
 202			   "tgtdev (devid %llu) is missing, need to run 'btrfs dev scan'?",
 203				BTRFS_DEV_REPLACE_DEVID);
 204		}
 205		if (dev_replace->tgtdev) {
 206			if (dev_replace->srcdev) {
 207				dev_replace->tgtdev->total_bytes =
 208					dev_replace->srcdev->total_bytes;
 209				dev_replace->tgtdev->disk_total_bytes =
 210					dev_replace->srcdev->disk_total_bytes;
 211				dev_replace->tgtdev->commit_total_bytes =
 212					dev_replace->srcdev->commit_total_bytes;
 213				dev_replace->tgtdev->bytes_used =
 214					dev_replace->srcdev->bytes_used;
 215				dev_replace->tgtdev->commit_bytes_used =
 216					dev_replace->srcdev->commit_bytes_used;
 217			}
 218			set_bit(BTRFS_DEV_STATE_REPLACE_TGT,
 219				&dev_replace->tgtdev->dev_state);
 220
 221			WARN_ON(fs_info->fs_devices->rw_devices == 0);
 222			dev_replace->tgtdev->io_width = fs_info->sectorsize;
 223			dev_replace->tgtdev->io_align = fs_info->sectorsize;
 224			dev_replace->tgtdev->sector_size = fs_info->sectorsize;
 225			dev_replace->tgtdev->fs_info = fs_info;
 226			set_bit(BTRFS_DEV_STATE_IN_FS_METADATA,
 227				&dev_replace->tgtdev->dev_state);
 228		}
 229		break;
 230	}
 231
 232out:
 233	btrfs_free_path(path);
 234	return ret;
 235}
 236
 237/*
 238 * Initialize a new device for device replace target from a given source dev
 239 * and path.
 240 *
 241 * Return 0 and new device in @device_out, otherwise return < 0
 242 */
 243static int btrfs_init_dev_replace_tgtdev(struct btrfs_fs_info *fs_info,
 244				  const char *device_path,
 245				  struct btrfs_device *srcdev,
 246				  struct btrfs_device **device_out)
 247{
 248	struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
 249	struct btrfs_device *device;
 250	struct block_device *bdev;
 
 
 251	u64 devid = BTRFS_DEV_REPLACE_DEVID;
 252	int ret = 0;
 253
 254	*device_out = NULL;
 255	if (srcdev->fs_devices->seeding) {
 256		btrfs_err(fs_info, "the filesystem is a seed filesystem!");
 257		return -EINVAL;
 258	}
 259
 260	bdev = blkdev_get_by_path(device_path, FMODE_WRITE | FMODE_EXCL,
 261				  fs_info->bdev_holder);
 262	if (IS_ERR(bdev)) {
 263		btrfs_err(fs_info, "target device %s is invalid!", device_path);
 264		return PTR_ERR(bdev);
 265	}
 266
 267	if (!btrfs_check_device_zone_type(fs_info, bdev)) {
 268		btrfs_err(fs_info,
 269		"dev-replace: zoned type of target device mismatch with filesystem");
 270		ret = -EINVAL;
 271		goto error;
 272	}
 273
 274	sync_blockdev(bdev);
 275
 276	list_for_each_entry(device, &fs_devices->devices, dev_list) {
 
 277		if (device->bdev == bdev) {
 278			btrfs_err(fs_info,
 279				  "target device is in the filesystem!");
 280			ret = -EEXIST;
 281			goto error;
 282		}
 283	}
 284
 285
 286	if (bdev_nr_bytes(bdev) < btrfs_device_get_total_bytes(srcdev)) {
 
 287		btrfs_err(fs_info,
 288			  "target device is smaller than source device!");
 289		ret = -EINVAL;
 290		goto error;
 291	}
 292
 293
 294	device = btrfs_alloc_device(NULL, &devid, NULL, device_path);
 295	if (IS_ERR(device)) {
 296		ret = PTR_ERR(device);
 297		goto error;
 298	}
 299
 300	ret = lookup_bdev(device_path, &device->devt);
 301	if (ret)
 
 
 302		goto error;
 
 
 303
 304	set_bit(BTRFS_DEV_STATE_WRITEABLE, &device->dev_state);
 305	device->generation = 0;
 306	device->io_width = fs_info->sectorsize;
 307	device->io_align = fs_info->sectorsize;
 308	device->sector_size = fs_info->sectorsize;
 309	device->total_bytes = btrfs_device_get_total_bytes(srcdev);
 310	device->disk_total_bytes = btrfs_device_get_disk_total_bytes(srcdev);
 311	device->bytes_used = btrfs_device_get_bytes_used(srcdev);
 312	device->commit_total_bytes = srcdev->commit_total_bytes;
 313	device->commit_bytes_used = device->bytes_used;
 314	device->fs_info = fs_info;
 315	device->bdev = bdev;
 316	set_bit(BTRFS_DEV_STATE_IN_FS_METADATA, &device->dev_state);
 317	set_bit(BTRFS_DEV_STATE_REPLACE_TGT, &device->dev_state);
 318	device->mode = FMODE_EXCL;
 319	device->dev_stats_valid = 1;
 320	set_blocksize(device->bdev, BTRFS_BDEV_BLOCKSIZE);
 321	device->fs_devices = fs_devices;
 322
 323	ret = btrfs_get_dev_zone_info(device, false);
 324	if (ret)
 325		goto error;
 326
 327	mutex_lock(&fs_devices->device_list_mutex);
 328	list_add(&device->dev_list, &fs_devices->devices);
 329	fs_devices->num_devices++;
 330	fs_devices->open_devices++;
 331	mutex_unlock(&fs_devices->device_list_mutex);
 332
 333	*device_out = device;
 334	return 0;
 335
 336error:
 337	blkdev_put(bdev, FMODE_EXCL);
 338	return ret;
 339}
 340
 341/*
 342 * called from commit_transaction. Writes changed device replace state to
 343 * disk.
 344 */
 345int btrfs_run_dev_replace(struct btrfs_trans_handle *trans)
 346{
 347	struct btrfs_fs_info *fs_info = trans->fs_info;
 348	int ret;
 349	struct btrfs_root *dev_root = fs_info->dev_root;
 350	struct btrfs_path *path;
 351	struct btrfs_key key;
 352	struct extent_buffer *eb;
 353	struct btrfs_dev_replace_item *ptr;
 354	struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
 355
 356	down_read(&dev_replace->rwsem);
 357	if (!dev_replace->is_valid ||
 358	    !dev_replace->item_needs_writeback) {
 359		up_read(&dev_replace->rwsem);
 360		return 0;
 361	}
 362	up_read(&dev_replace->rwsem);
 363
 364	key.objectid = 0;
 365	key.type = BTRFS_DEV_REPLACE_KEY;
 366	key.offset = 0;
 367
 368	path = btrfs_alloc_path();
 369	if (!path) {
 370		ret = -ENOMEM;
 371		goto out;
 372	}
 373	ret = btrfs_search_slot(trans, dev_root, &key, path, -1, 1);
 374	if (ret < 0) {
 375		btrfs_warn(fs_info,
 376			   "error %d while searching for dev_replace item!",
 377			   ret);
 378		goto out;
 379	}
 380
 381	if (ret == 0 &&
 382	    btrfs_item_size(path->nodes[0], path->slots[0]) < sizeof(*ptr)) {
 383		/*
 384		 * need to delete old one and insert a new one.
 385		 * Since no attempt is made to recover any old state, if the
 386		 * dev_replace state is 'running', the data on the target
 387		 * drive is lost.
 388		 * It would be possible to recover the state: just make sure
 389		 * that the beginning of the item is never changed and always
 390		 * contains all the essential information. Then read this
 391		 * minimal set of information and use it as a base for the
 392		 * new state.
 393		 */
 394		ret = btrfs_del_item(trans, dev_root, path);
 395		if (ret != 0) {
 396			btrfs_warn(fs_info,
 397				   "delete too small dev_replace item failed %d!",
 398				   ret);
 399			goto out;
 400		}
 401		ret = 1;
 402	}
 403
 404	if (ret == 1) {
 405		/* need to insert a new item */
 406		btrfs_release_path(path);
 407		ret = btrfs_insert_empty_item(trans, dev_root, path,
 408					      &key, sizeof(*ptr));
 409		if (ret < 0) {
 410			btrfs_warn(fs_info,
 411				   "insert dev_replace item failed %d!", ret);
 412			goto out;
 413		}
 414	}
 415
 416	eb = path->nodes[0];
 417	ptr = btrfs_item_ptr(eb, path->slots[0],
 418			     struct btrfs_dev_replace_item);
 419
 420	down_write(&dev_replace->rwsem);
 421	if (dev_replace->srcdev)
 422		btrfs_set_dev_replace_src_devid(eb, ptr,
 423			dev_replace->srcdev->devid);
 424	else
 425		btrfs_set_dev_replace_src_devid(eb, ptr, (u64)-1);
 426	btrfs_set_dev_replace_cont_reading_from_srcdev_mode(eb, ptr,
 427		dev_replace->cont_reading_from_srcdev_mode);
 428	btrfs_set_dev_replace_replace_state(eb, ptr,
 429		dev_replace->replace_state);
 430	btrfs_set_dev_replace_time_started(eb, ptr, dev_replace->time_started);
 431	btrfs_set_dev_replace_time_stopped(eb, ptr, dev_replace->time_stopped);
 432	btrfs_set_dev_replace_num_write_errors(eb, ptr,
 433		atomic64_read(&dev_replace->num_write_errors));
 434	btrfs_set_dev_replace_num_uncorrectable_read_errors(eb, ptr,
 435		atomic64_read(&dev_replace->num_uncorrectable_read_errors));
 436	dev_replace->cursor_left_last_write_of_item =
 437		dev_replace->cursor_left;
 438	btrfs_set_dev_replace_cursor_left(eb, ptr,
 439		dev_replace->cursor_left_last_write_of_item);
 440	btrfs_set_dev_replace_cursor_right(eb, ptr,
 441		dev_replace->cursor_right);
 442	dev_replace->item_needs_writeback = 0;
 443	up_write(&dev_replace->rwsem);
 444
 445	btrfs_mark_buffer_dirty(eb);
 446
 447out:
 448	btrfs_free_path(path);
 449
 450	return ret;
 451}
 452
 453static int mark_block_group_to_copy(struct btrfs_fs_info *fs_info,
 454				    struct btrfs_device *src_dev)
 455{
 456	struct btrfs_path *path;
 457	struct btrfs_key key;
 458	struct btrfs_key found_key;
 459	struct btrfs_root *root = fs_info->dev_root;
 460	struct btrfs_dev_extent *dev_extent = NULL;
 461	struct btrfs_block_group *cache;
 462	struct btrfs_trans_handle *trans;
 463	int iter_ret = 0;
 464	int ret = 0;
 465	u64 chunk_offset;
 466
 467	/* Do not use "to_copy" on non zoned filesystem for now */
 468	if (!btrfs_is_zoned(fs_info))
 469		return 0;
 470
 471	mutex_lock(&fs_info->chunk_mutex);
 472
 473	/* Ensure we don't have pending new block group */
 474	spin_lock(&fs_info->trans_lock);
 475	while (fs_info->running_transaction &&
 476	       !list_empty(&fs_info->running_transaction->dev_update_list)) {
 477		spin_unlock(&fs_info->trans_lock);
 478		mutex_unlock(&fs_info->chunk_mutex);
 479		trans = btrfs_attach_transaction(root);
 480		if (IS_ERR(trans)) {
 481			ret = PTR_ERR(trans);
 482			mutex_lock(&fs_info->chunk_mutex);
 483			if (ret == -ENOENT) {
 484				spin_lock(&fs_info->trans_lock);
 485				continue;
 486			} else {
 487				goto unlock;
 488			}
 489		}
 490
 491		ret = btrfs_commit_transaction(trans);
 492		mutex_lock(&fs_info->chunk_mutex);
 493		if (ret)
 494			goto unlock;
 495
 496		spin_lock(&fs_info->trans_lock);
 497	}
 498	spin_unlock(&fs_info->trans_lock);
 499
 500	path = btrfs_alloc_path();
 501	if (!path) {
 502		ret = -ENOMEM;
 503		goto unlock;
 504	}
 505
 506	path->reada = READA_FORWARD;
 507	path->search_commit_root = 1;
 508	path->skip_locking = 1;
 509
 510	key.objectid = src_dev->devid;
 511	key.type = BTRFS_DEV_EXTENT_KEY;
 512	key.offset = 0;
 513
 514	btrfs_for_each_slot(root, &key, &found_key, path, iter_ret) {
 515		struct extent_buffer *leaf = path->nodes[0];
 516
 517		if (found_key.objectid != src_dev->devid)
 518			break;
 519
 520		if (found_key.type != BTRFS_DEV_EXTENT_KEY)
 521			break;
 522
 523		if (found_key.offset < key.offset)
 524			break;
 525
 526		dev_extent = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dev_extent);
 527
 528		chunk_offset = btrfs_dev_extent_chunk_offset(leaf, dev_extent);
 529
 530		cache = btrfs_lookup_block_group(fs_info, chunk_offset);
 531		if (!cache)
 532			continue;
 533
 534		set_bit(BLOCK_GROUP_FLAG_TO_COPY, &cache->runtime_flags);
 535		btrfs_put_block_group(cache);
 536	}
 537	if (iter_ret < 0)
 538		ret = iter_ret;
 539
 540	btrfs_free_path(path);
 541unlock:
 542	mutex_unlock(&fs_info->chunk_mutex);
 543
 544	return ret;
 545}
 546
 547bool btrfs_finish_block_group_to_copy(struct btrfs_device *srcdev,
 548				      struct btrfs_block_group *cache,
 549				      u64 physical)
 550{
 551	struct btrfs_fs_info *fs_info = cache->fs_info;
 552	struct extent_map *em;
 553	struct map_lookup *map;
 554	u64 chunk_offset = cache->start;
 555	int num_extents, cur_extent;
 556	int i;
 557
 558	/* Do not use "to_copy" on non zoned filesystem for now */
 559	if (!btrfs_is_zoned(fs_info))
 560		return true;
 561
 562	spin_lock(&cache->lock);
 563	if (test_bit(BLOCK_GROUP_FLAG_REMOVED, &cache->runtime_flags)) {
 564		spin_unlock(&cache->lock);
 565		return true;
 566	}
 567	spin_unlock(&cache->lock);
 568
 569	em = btrfs_get_chunk_map(fs_info, chunk_offset, 1);
 570	ASSERT(!IS_ERR(em));
 571	map = em->map_lookup;
 572
 573	num_extents = 0;
 574	cur_extent = 0;
 575	for (i = 0; i < map->num_stripes; i++) {
 576		/* We have more device extent to copy */
 577		if (srcdev != map->stripes[i].dev)
 578			continue;
 579
 580		num_extents++;
 581		if (physical == map->stripes[i].physical)
 582			cur_extent = i;
 583	}
 584
 585	free_extent_map(em);
 586
 587	if (num_extents > 1 && cur_extent < num_extents - 1) {
 588		/*
 589		 * Has more stripes on this device. Keep this block group
 590		 * readonly until we finish all the stripes.
 591		 */
 592		return false;
 593	}
 594
 595	/* Last stripe on this device */
 596	clear_bit(BLOCK_GROUP_FLAG_TO_COPY, &cache->runtime_flags);
 597
 598	return true;
 599}
 600
 601static int btrfs_dev_replace_start(struct btrfs_fs_info *fs_info,
 602		const char *tgtdev_name, u64 srcdevid, const char *srcdev_name,
 603		int read_src)
 604{
 605	struct btrfs_root *root = fs_info->dev_root;
 606	struct btrfs_trans_handle *trans;
 607	struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
 608	int ret;
 609	struct btrfs_device *tgt_device = NULL;
 610	struct btrfs_device *src_device = NULL;
 611
 612	src_device = btrfs_find_device_by_devspec(fs_info, srcdevid,
 613						  srcdev_name);
 614	if (IS_ERR(src_device))
 615		return PTR_ERR(src_device);
 616
 617	if (btrfs_pinned_by_swapfile(fs_info, src_device)) {
 618		btrfs_warn_in_rcu(fs_info,
 619	  "cannot replace device %s (devid %llu) due to active swapfile",
 620			btrfs_dev_name(src_device), src_device->devid);
 621		return -ETXTBSY;
 622	}
 623
 624	/*
 625	 * Here we commit the transaction to make sure commit_total_bytes
 626	 * of all the devices are updated.
 627	 */
 628	trans = btrfs_attach_transaction(root);
 629	if (!IS_ERR(trans)) {
 630		ret = btrfs_commit_transaction(trans);
 631		if (ret)
 632			return ret;
 633	} else if (PTR_ERR(trans) != -ENOENT) {
 634		return PTR_ERR(trans);
 635	}
 636
 637	ret = btrfs_init_dev_replace_tgtdev(fs_info, tgtdev_name,
 638					    src_device, &tgt_device);
 639	if (ret)
 640		return ret;
 641
 642	ret = mark_block_group_to_copy(fs_info, src_device);
 643	if (ret)
 644		return ret;
 645
 646	down_write(&dev_replace->rwsem);
 647	switch (dev_replace->replace_state) {
 648	case BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED:
 649	case BTRFS_IOCTL_DEV_REPLACE_STATE_FINISHED:
 650	case BTRFS_IOCTL_DEV_REPLACE_STATE_CANCELED:
 651		break;
 652	case BTRFS_IOCTL_DEV_REPLACE_STATE_STARTED:
 653	case BTRFS_IOCTL_DEV_REPLACE_STATE_SUSPENDED:
 654		ASSERT(0);
 655		ret = BTRFS_IOCTL_DEV_REPLACE_RESULT_ALREADY_STARTED;
 656		up_write(&dev_replace->rwsem);
 657		goto leave;
 658	}
 659
 660	dev_replace->cont_reading_from_srcdev_mode = read_src;
 661	dev_replace->srcdev = src_device;
 662	dev_replace->tgtdev = tgt_device;
 663
 664	btrfs_info_in_rcu(fs_info,
 665		      "dev_replace from %s (devid %llu) to %s started",
 666		      btrfs_dev_name(src_device),
 667		      src_device->devid,
 668		      btrfs_dev_name(tgt_device));
 669
 670	/*
 671	 * from now on, the writes to the srcdev are all duplicated to
 672	 * go to the tgtdev as well (refer to btrfs_map_block()).
 673	 */
 674	dev_replace->replace_state = BTRFS_IOCTL_DEV_REPLACE_STATE_STARTED;
 675	dev_replace->time_started = ktime_get_real_seconds();
 676	dev_replace->cursor_left = 0;
 677	dev_replace->committed_cursor_left = 0;
 678	dev_replace->cursor_left_last_write_of_item = 0;
 679	dev_replace->cursor_right = 0;
 680	dev_replace->is_valid = 1;
 681	dev_replace->item_needs_writeback = 1;
 682	atomic64_set(&dev_replace->num_write_errors, 0);
 683	atomic64_set(&dev_replace->num_uncorrectable_read_errors, 0);
 684	up_write(&dev_replace->rwsem);
 685
 686	ret = btrfs_sysfs_add_device(tgt_device);
 687	if (ret)
 688		btrfs_err(fs_info, "kobj add dev failed %d", ret);
 689
 690	btrfs_wait_ordered_roots(fs_info, U64_MAX, 0, (u64)-1);
 691
 692	/*
 693	 * Commit dev_replace state and reserve 1 item for it.
 694	 * This is crucial to ensure we won't miss copying extents for new block
 695	 * groups that are allocated after we started the device replace, and
 696	 * must be done after setting up the device replace state.
 697	 */
 698	trans = btrfs_start_transaction(root, 1);
 699	if (IS_ERR(trans)) {
 700		ret = PTR_ERR(trans);
 701		down_write(&dev_replace->rwsem);
 702		dev_replace->replace_state =
 703			BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED;
 704		dev_replace->srcdev = NULL;
 705		dev_replace->tgtdev = NULL;
 706		up_write(&dev_replace->rwsem);
 707		goto leave;
 708	}
 709
 710	ret = btrfs_commit_transaction(trans);
 711	WARN_ON(ret);
 712
 713	/* the disk copy procedure reuses the scrub code */
 714	ret = btrfs_scrub_dev(fs_info, src_device->devid, 0,
 715			      btrfs_device_get_total_bytes(src_device),
 716			      &dev_replace->scrub_progress, 0, 1);
 717
 718	ret = btrfs_dev_replace_finishing(fs_info, ret);
 719	if (ret == -EINPROGRESS)
 720		ret = BTRFS_IOCTL_DEV_REPLACE_RESULT_SCRUB_INPROGRESS;
 721
 722	return ret;
 723
 724leave:
 725	btrfs_destroy_dev_replace_tgtdev(tgt_device);
 726	return ret;
 727}
 728
 729int btrfs_dev_replace_by_ioctl(struct btrfs_fs_info *fs_info,
 730			    struct btrfs_ioctl_dev_replace_args *args)
 731{
 732	int ret;
 733
 734	switch (args->start.cont_reading_from_srcdev_mode) {
 735	case BTRFS_IOCTL_DEV_REPLACE_CONT_READING_FROM_SRCDEV_MODE_ALWAYS:
 736	case BTRFS_IOCTL_DEV_REPLACE_CONT_READING_FROM_SRCDEV_MODE_AVOID:
 737		break;
 738	default:
 739		return -EINVAL;
 740	}
 741
 742	if ((args->start.srcdevid == 0 && args->start.srcdev_name[0] == '\0') ||
 743	    args->start.tgtdev_name[0] == '\0')
 744		return -EINVAL;
 745
 746	ret = btrfs_dev_replace_start(fs_info, args->start.tgtdev_name,
 747					args->start.srcdevid,
 748					args->start.srcdev_name,
 749					args->start.cont_reading_from_srcdev_mode);
 750	args->result = ret;
 751	/* don't warn if EINPROGRESS, someone else might be running scrub */
 752	if (ret == BTRFS_IOCTL_DEV_REPLACE_RESULT_SCRUB_INPROGRESS ||
 753	    ret == BTRFS_IOCTL_DEV_REPLACE_RESULT_NO_ERROR)
 754		return 0;
 755
 756	return ret;
 757}
 758
 759/*
 760 * blocked until all in-flight bios operations are finished.
 761 */
 762static void btrfs_rm_dev_replace_blocked(struct btrfs_fs_info *fs_info)
 763{
 764	set_bit(BTRFS_FS_STATE_DEV_REPLACING, &fs_info->fs_state);
 765	wait_event(fs_info->dev_replace.replace_wait, !percpu_counter_sum(
 766		   &fs_info->dev_replace.bio_counter));
 767}
 768
 769/*
 770 * we have removed target device, it is safe to allow new bios request.
 771 */
 772static void btrfs_rm_dev_replace_unblocked(struct btrfs_fs_info *fs_info)
 773{
 774	clear_bit(BTRFS_FS_STATE_DEV_REPLACING, &fs_info->fs_state);
 775	wake_up(&fs_info->dev_replace.replace_wait);
 776}
 777
 778/*
 779 * When finishing the device replace, before swapping the source device with the
 780 * target device we must update the chunk allocation state in the target device,
 781 * as it is empty because replace works by directly copying the chunks and not
 782 * through the normal chunk allocation path.
 783 */
 784static int btrfs_set_target_alloc_state(struct btrfs_device *srcdev,
 785					struct btrfs_device *tgtdev)
 786{
 787	struct extent_state *cached_state = NULL;
 788	u64 start = 0;
 789	u64 found_start;
 790	u64 found_end;
 791	int ret = 0;
 792
 793	lockdep_assert_held(&srcdev->fs_info->chunk_mutex);
 794
 795	while (!find_first_extent_bit(&srcdev->alloc_state, start,
 796				      &found_start, &found_end,
 797				      CHUNK_ALLOCATED, &cached_state)) {
 798		ret = set_extent_bits(&tgtdev->alloc_state, found_start,
 799				      found_end, CHUNK_ALLOCATED);
 800		if (ret)
 801			break;
 802		start = found_end + 1;
 803	}
 804
 805	free_extent_state(cached_state);
 806	return ret;
 807}
 808
 809static void btrfs_dev_replace_update_device_in_mapping_tree(
 810						struct btrfs_fs_info *fs_info,
 811						struct btrfs_device *srcdev,
 812						struct btrfs_device *tgtdev)
 813{
 814	struct extent_map_tree *em_tree = &fs_info->mapping_tree;
 815	struct extent_map *em;
 816	struct map_lookup *map;
 817	u64 start = 0;
 818	int i;
 819
 820	write_lock(&em_tree->lock);
 821	do {
 822		em = lookup_extent_mapping(em_tree, start, (u64)-1);
 823		if (!em)
 824			break;
 825		map = em->map_lookup;
 826		for (i = 0; i < map->num_stripes; i++)
 827			if (srcdev == map->stripes[i].dev)
 828				map->stripes[i].dev = tgtdev;
 829		start = em->start + em->len;
 830		free_extent_map(em);
 831	} while (start);
 832	write_unlock(&em_tree->lock);
 833}
 834
 835static int btrfs_dev_replace_finishing(struct btrfs_fs_info *fs_info,
 836				       int scrub_ret)
 837{
 838	struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
 839	struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
 840	struct btrfs_device *tgt_device;
 841	struct btrfs_device *src_device;
 842	struct btrfs_root *root = fs_info->tree_root;
 843	u8 uuid_tmp[BTRFS_UUID_SIZE];
 844	struct btrfs_trans_handle *trans;
 845	int ret = 0;
 846
 847	/* don't allow cancel or unmount to disturb the finishing procedure */
 848	mutex_lock(&dev_replace->lock_finishing_cancel_unmount);
 849
 850	down_read(&dev_replace->rwsem);
 851	/* was the operation canceled, or is it finished? */
 852	if (dev_replace->replace_state !=
 853	    BTRFS_IOCTL_DEV_REPLACE_STATE_STARTED) {
 854		up_read(&dev_replace->rwsem);
 855		mutex_unlock(&dev_replace->lock_finishing_cancel_unmount);
 856		return 0;
 857	}
 858
 859	tgt_device = dev_replace->tgtdev;
 860	src_device = dev_replace->srcdev;
 861	up_read(&dev_replace->rwsem);
 862
 863	/*
 864	 * flush all outstanding I/O and inode extent mappings before the
 865	 * copy operation is declared as being finished
 866	 */
 867	ret = btrfs_start_delalloc_roots(fs_info, LONG_MAX, false);
 868	if (ret) {
 869		mutex_unlock(&dev_replace->lock_finishing_cancel_unmount);
 870		return ret;
 871	}
 872	btrfs_wait_ordered_roots(fs_info, U64_MAX, 0, (u64)-1);
 873
 874	/*
 875	 * We have to use this loop approach because at this point src_device
 876	 * has to be available for transaction commit to complete, yet new
 877	 * chunks shouldn't be allocated on the device.
 878	 */
 879	while (1) {
 880		trans = btrfs_start_transaction(root, 0);
 881		if (IS_ERR(trans)) {
 882			mutex_unlock(&dev_replace->lock_finishing_cancel_unmount);
 883			return PTR_ERR(trans);
 884		}
 885		ret = btrfs_commit_transaction(trans);
 886		WARN_ON(ret);
 887
 888		/* Prevent write_all_supers() during the finishing procedure */
 889		mutex_lock(&fs_devices->device_list_mutex);
 890		/* Prevent new chunks being allocated on the source device */
 891		mutex_lock(&fs_info->chunk_mutex);
 892
 893		if (!list_empty(&src_device->post_commit_list)) {
 894			mutex_unlock(&fs_devices->device_list_mutex);
 895			mutex_unlock(&fs_info->chunk_mutex);
 896		} else {
 897			break;
 898		}
 899	}
 900
 901	down_write(&dev_replace->rwsem);
 902	dev_replace->replace_state =
 903		scrub_ret ? BTRFS_IOCTL_DEV_REPLACE_STATE_CANCELED
 904			  : BTRFS_IOCTL_DEV_REPLACE_STATE_FINISHED;
 905	dev_replace->tgtdev = NULL;
 906	dev_replace->srcdev = NULL;
 907	dev_replace->time_stopped = ktime_get_real_seconds();
 908	dev_replace->item_needs_writeback = 1;
 909
 910	/*
 911	 * Update allocation state in the new device and replace the old device
 912	 * with the new one in the mapping tree.
 913	 */
 914	if (!scrub_ret) {
 915		scrub_ret = btrfs_set_target_alloc_state(src_device, tgt_device);
 916		if (scrub_ret)
 917			goto error;
 918		btrfs_dev_replace_update_device_in_mapping_tree(fs_info,
 919								src_device,
 920								tgt_device);
 921	} else {
 922		if (scrub_ret != -ECANCELED)
 923			btrfs_err_in_rcu(fs_info,
 924				 "btrfs_scrub_dev(%s, %llu, %s) failed %d",
 925				 btrfs_dev_name(src_device),
 926				 src_device->devid,
 927				 btrfs_dev_name(tgt_device), scrub_ret);
 928error:
 929		up_write(&dev_replace->rwsem);
 930		mutex_unlock(&fs_info->chunk_mutex);
 931		mutex_unlock(&fs_devices->device_list_mutex);
 932		btrfs_rm_dev_replace_blocked(fs_info);
 933		if (tgt_device)
 934			btrfs_destroy_dev_replace_tgtdev(tgt_device);
 935		btrfs_rm_dev_replace_unblocked(fs_info);
 936		mutex_unlock(&dev_replace->lock_finishing_cancel_unmount);
 937
 938		return scrub_ret;
 939	}
 940
 941	btrfs_info_in_rcu(fs_info,
 942			  "dev_replace from %s (devid %llu) to %s finished",
 943			  btrfs_dev_name(src_device),
 944			  src_device->devid,
 945			  btrfs_dev_name(tgt_device));
 946	clear_bit(BTRFS_DEV_STATE_REPLACE_TGT, &tgt_device->dev_state);
 947	tgt_device->devid = src_device->devid;
 948	src_device->devid = BTRFS_DEV_REPLACE_DEVID;
 949	memcpy(uuid_tmp, tgt_device->uuid, sizeof(uuid_tmp));
 950	memcpy(tgt_device->uuid, src_device->uuid, sizeof(tgt_device->uuid));
 951	memcpy(src_device->uuid, uuid_tmp, sizeof(src_device->uuid));
 952	btrfs_device_set_total_bytes(tgt_device, src_device->total_bytes);
 953	btrfs_device_set_disk_total_bytes(tgt_device,
 954					  src_device->disk_total_bytes);
 955	btrfs_device_set_bytes_used(tgt_device, src_device->bytes_used);
 956	tgt_device->commit_bytes_used = src_device->bytes_used;
 957
 958	btrfs_assign_next_active_device(src_device, tgt_device);
 959
 960	list_add(&tgt_device->dev_alloc_list, &fs_devices->alloc_list);
 961	fs_devices->rw_devices++;
 962
 963	up_write(&dev_replace->rwsem);
 964	btrfs_rm_dev_replace_blocked(fs_info);
 965
 966	btrfs_rm_dev_replace_remove_srcdev(src_device);
 967
 968	btrfs_rm_dev_replace_unblocked(fs_info);
 969
 970	/*
 971	 * Increment dev_stats_ccnt so that btrfs_run_dev_stats() will
 972	 * update on-disk dev stats value during commit transaction
 973	 */
 974	atomic_inc(&tgt_device->dev_stats_ccnt);
 975
 976	/*
 977	 * this is again a consistent state where no dev_replace procedure
 978	 * is running, the target device is part of the filesystem, the
 979	 * source device is not part of the filesystem anymore and its 1st
 980	 * superblock is scratched out so that it is no longer marked to
 981	 * belong to this filesystem.
 982	 */
 983	mutex_unlock(&fs_info->chunk_mutex);
 984	mutex_unlock(&fs_devices->device_list_mutex);
 985
 986	/* replace the sysfs entry */
 987	btrfs_sysfs_remove_device(src_device);
 988	btrfs_sysfs_update_devid(tgt_device);
 989	if (test_bit(BTRFS_DEV_STATE_WRITEABLE, &src_device->dev_state))
 990		btrfs_scratch_superblocks(fs_info, src_device->bdev,
 991					  src_device->name->str);
 992
 993	/* write back the superblocks */
 994	trans = btrfs_start_transaction(root, 0);
 995	if (!IS_ERR(trans))
 996		btrfs_commit_transaction(trans);
 997
 998	mutex_unlock(&dev_replace->lock_finishing_cancel_unmount);
 999
1000	btrfs_rm_dev_replace_free_srcdev(src_device);
1001
1002	return 0;
1003}
1004
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1005/*
1006 * Read progress of device replace status according to the state and last
1007 * stored position. The value format is the same as for
1008 * btrfs_dev_replace::progress_1000
1009 */
1010static u64 btrfs_dev_replace_progress(struct btrfs_fs_info *fs_info)
1011{
1012	struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
1013	u64 ret = 0;
1014
1015	switch (dev_replace->replace_state) {
1016	case BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED:
1017	case BTRFS_IOCTL_DEV_REPLACE_STATE_CANCELED:
1018		ret = 0;
1019		break;
1020	case BTRFS_IOCTL_DEV_REPLACE_STATE_FINISHED:
1021		ret = 1000;
1022		break;
1023	case BTRFS_IOCTL_DEV_REPLACE_STATE_STARTED:
1024	case BTRFS_IOCTL_DEV_REPLACE_STATE_SUSPENDED:
1025		ret = div64_u64(dev_replace->cursor_left,
1026				div_u64(btrfs_device_get_total_bytes(
1027						dev_replace->srcdev), 1000));
1028		break;
1029	}
1030
1031	return ret;
1032}
1033
1034void btrfs_dev_replace_status(struct btrfs_fs_info *fs_info,
1035			      struct btrfs_ioctl_dev_replace_args *args)
1036{
1037	struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
1038
1039	down_read(&dev_replace->rwsem);
1040	/* even if !dev_replace_is_valid, the values are good enough for
1041	 * the replace_status ioctl */
1042	args->result = BTRFS_IOCTL_DEV_REPLACE_RESULT_NO_ERROR;
1043	args->status.replace_state = dev_replace->replace_state;
1044	args->status.time_started = dev_replace->time_started;
1045	args->status.time_stopped = dev_replace->time_stopped;
1046	args->status.num_write_errors =
1047		atomic64_read(&dev_replace->num_write_errors);
1048	args->status.num_uncorrectable_read_errors =
1049		atomic64_read(&dev_replace->num_uncorrectable_read_errors);
1050	args->status.progress_1000 = btrfs_dev_replace_progress(fs_info);
1051	up_read(&dev_replace->rwsem);
1052}
1053
1054int btrfs_dev_replace_cancel(struct btrfs_fs_info *fs_info)
1055{
1056	struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
1057	struct btrfs_device *tgt_device = NULL;
1058	struct btrfs_device *src_device = NULL;
1059	struct btrfs_trans_handle *trans;
1060	struct btrfs_root *root = fs_info->tree_root;
1061	int result;
1062	int ret;
1063
1064	if (sb_rdonly(fs_info->sb))
1065		return -EROFS;
1066
1067	mutex_lock(&dev_replace->lock_finishing_cancel_unmount);
1068	down_write(&dev_replace->rwsem);
1069	switch (dev_replace->replace_state) {
1070	case BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED:
1071	case BTRFS_IOCTL_DEV_REPLACE_STATE_FINISHED:
1072	case BTRFS_IOCTL_DEV_REPLACE_STATE_CANCELED:
1073		result = BTRFS_IOCTL_DEV_REPLACE_RESULT_NOT_STARTED;
1074		up_write(&dev_replace->rwsem);
1075		break;
1076	case BTRFS_IOCTL_DEV_REPLACE_STATE_STARTED:
1077		tgt_device = dev_replace->tgtdev;
1078		src_device = dev_replace->srcdev;
1079		up_write(&dev_replace->rwsem);
1080		ret = btrfs_scrub_cancel(fs_info);
1081		if (ret < 0) {
1082			result = BTRFS_IOCTL_DEV_REPLACE_RESULT_NOT_STARTED;
1083		} else {
1084			result = BTRFS_IOCTL_DEV_REPLACE_RESULT_NO_ERROR;
1085			/*
1086			 * btrfs_dev_replace_finishing() will handle the
1087			 * cleanup part
1088			 */
1089			btrfs_info_in_rcu(fs_info,
1090				"dev_replace from %s (devid %llu) to %s canceled",
1091				btrfs_dev_name(src_device), src_device->devid,
1092				btrfs_dev_name(tgt_device));
1093		}
1094		break;
1095	case BTRFS_IOCTL_DEV_REPLACE_STATE_SUSPENDED:
1096		/*
1097		 * Scrub doing the replace isn't running so we need to do the
1098		 * cleanup step of btrfs_dev_replace_finishing() here
1099		 */
1100		result = BTRFS_IOCTL_DEV_REPLACE_RESULT_NO_ERROR;
1101		tgt_device = dev_replace->tgtdev;
1102		src_device = dev_replace->srcdev;
1103		dev_replace->tgtdev = NULL;
1104		dev_replace->srcdev = NULL;
1105		dev_replace->replace_state =
1106				BTRFS_IOCTL_DEV_REPLACE_STATE_CANCELED;
1107		dev_replace->time_stopped = ktime_get_real_seconds();
1108		dev_replace->item_needs_writeback = 1;
1109
1110		up_write(&dev_replace->rwsem);
1111
1112		/* Scrub for replace must not be running in suspended state */
1113		btrfs_scrub_cancel(fs_info);
 
1114
1115		trans = btrfs_start_transaction(root, 0);
1116		if (IS_ERR(trans)) {
1117			mutex_unlock(&dev_replace->lock_finishing_cancel_unmount);
1118			return PTR_ERR(trans);
1119		}
1120		ret = btrfs_commit_transaction(trans);
1121		WARN_ON(ret);
1122
1123		btrfs_info_in_rcu(fs_info,
1124		"suspended dev_replace from %s (devid %llu) to %s canceled",
1125			btrfs_dev_name(src_device), src_device->devid,
1126			btrfs_dev_name(tgt_device));
1127
1128		if (tgt_device)
1129			btrfs_destroy_dev_replace_tgtdev(tgt_device);
1130		break;
1131	default:
1132		up_write(&dev_replace->rwsem);
1133		result = -EINVAL;
1134	}
1135
1136	mutex_unlock(&dev_replace->lock_finishing_cancel_unmount);
1137	return result;
1138}
1139
1140void btrfs_dev_replace_suspend_for_unmount(struct btrfs_fs_info *fs_info)
1141{
1142	struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
1143
1144	mutex_lock(&dev_replace->lock_finishing_cancel_unmount);
1145	down_write(&dev_replace->rwsem);
1146
1147	switch (dev_replace->replace_state) {
1148	case BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED:
1149	case BTRFS_IOCTL_DEV_REPLACE_STATE_FINISHED:
1150	case BTRFS_IOCTL_DEV_REPLACE_STATE_CANCELED:
1151	case BTRFS_IOCTL_DEV_REPLACE_STATE_SUSPENDED:
1152		break;
1153	case BTRFS_IOCTL_DEV_REPLACE_STATE_STARTED:
1154		dev_replace->replace_state =
1155			BTRFS_IOCTL_DEV_REPLACE_STATE_SUSPENDED;
1156		dev_replace->time_stopped = ktime_get_real_seconds();
1157		dev_replace->item_needs_writeback = 1;
1158		btrfs_info(fs_info, "suspending dev_replace for unmount");
1159		break;
1160	}
1161
1162	up_write(&dev_replace->rwsem);
1163	mutex_unlock(&dev_replace->lock_finishing_cancel_unmount);
1164}
1165
1166/* resume dev_replace procedure that was interrupted by unmount */
1167int btrfs_resume_dev_replace_async(struct btrfs_fs_info *fs_info)
1168{
1169	struct task_struct *task;
1170	struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
1171
1172	down_write(&dev_replace->rwsem);
1173
1174	switch (dev_replace->replace_state) {
1175	case BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED:
1176	case BTRFS_IOCTL_DEV_REPLACE_STATE_FINISHED:
1177	case BTRFS_IOCTL_DEV_REPLACE_STATE_CANCELED:
1178		up_write(&dev_replace->rwsem);
1179		return 0;
1180	case BTRFS_IOCTL_DEV_REPLACE_STATE_STARTED:
1181		break;
1182	case BTRFS_IOCTL_DEV_REPLACE_STATE_SUSPENDED:
1183		dev_replace->replace_state =
1184			BTRFS_IOCTL_DEV_REPLACE_STATE_STARTED;
1185		break;
1186	}
1187	if (!dev_replace->tgtdev || !dev_replace->tgtdev->bdev) {
1188		btrfs_info(fs_info,
1189			   "cannot continue dev_replace, tgtdev is missing");
1190		btrfs_info(fs_info,
1191			   "you may cancel the operation after 'mount -o degraded'");
1192		dev_replace->replace_state =
1193					BTRFS_IOCTL_DEV_REPLACE_STATE_SUSPENDED;
1194		up_write(&dev_replace->rwsem);
1195		return 0;
1196	}
1197	up_write(&dev_replace->rwsem);
1198
1199	/*
1200	 * This could collide with a paused balance, but the exclusive op logic
1201	 * should never allow both to start and pause. We don't want to allow
1202	 * dev-replace to start anyway.
1203	 */
1204	if (!btrfs_exclop_start(fs_info, BTRFS_EXCLOP_DEV_REPLACE)) {
1205		down_write(&dev_replace->rwsem);
1206		dev_replace->replace_state =
1207					BTRFS_IOCTL_DEV_REPLACE_STATE_SUSPENDED;
1208		up_write(&dev_replace->rwsem);
1209		btrfs_info(fs_info,
1210		"cannot resume dev-replace, other exclusive operation running");
1211		return 0;
1212	}
1213
1214	task = kthread_run(btrfs_dev_replace_kthread, fs_info, "btrfs-devrepl");
1215	return PTR_ERR_OR_ZERO(task);
1216}
1217
1218static int btrfs_dev_replace_kthread(void *data)
1219{
1220	struct btrfs_fs_info *fs_info = data;
1221	struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
1222	u64 progress;
1223	int ret;
1224
1225	progress = btrfs_dev_replace_progress(fs_info);
1226	progress = div_u64(progress, 10);
1227	btrfs_info_in_rcu(fs_info,
1228		"continuing dev_replace from %s (devid %llu) to target %s @%u%%",
1229		btrfs_dev_name(dev_replace->srcdev),
1230		dev_replace->srcdev->devid,
1231		btrfs_dev_name(dev_replace->tgtdev),
1232		(unsigned int)progress);
1233
1234	ret = btrfs_scrub_dev(fs_info, dev_replace->srcdev->devid,
1235			      dev_replace->committed_cursor_left,
1236			      btrfs_device_get_total_bytes(dev_replace->srcdev),
1237			      &dev_replace->scrub_progress, 0, 1);
1238	ret = btrfs_dev_replace_finishing(fs_info, ret);
1239	WARN_ON(ret && ret != -ECANCELED);
1240
1241	btrfs_exclop_finish(fs_info);
1242	return 0;
1243}
1244
1245int __pure btrfs_dev_replace_is_ongoing(struct btrfs_dev_replace *dev_replace)
1246{
1247	if (!dev_replace->is_valid)
1248		return 0;
1249
1250	switch (dev_replace->replace_state) {
1251	case BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED:
1252	case BTRFS_IOCTL_DEV_REPLACE_STATE_FINISHED:
1253	case BTRFS_IOCTL_DEV_REPLACE_STATE_CANCELED:
1254		return 0;
1255	case BTRFS_IOCTL_DEV_REPLACE_STATE_STARTED:
1256	case BTRFS_IOCTL_DEV_REPLACE_STATE_SUSPENDED:
1257		/*
1258		 * return true even if tgtdev is missing (this is
1259		 * something that can happen if the dev_replace
1260		 * procedure is suspended by an umount and then
1261		 * the tgtdev is missing (or "btrfs dev scan") was
1262		 * not called and the filesystem is remounted
1263		 * in degraded state. This does not stop the
1264		 * dev_replace procedure. It needs to be canceled
1265		 * manually if the cancellation is wanted.
1266		 */
1267		break;
1268	}
1269	return 1;
 
 
 
 
 
1270}
1271
1272void btrfs_bio_counter_sub(struct btrfs_fs_info *fs_info, s64 amount)
1273{
1274	percpu_counter_sub(&fs_info->dev_replace.bio_counter, amount);
1275	cond_wake_up_nomb(&fs_info->dev_replace.replace_wait);
1276}
1277
1278void btrfs_bio_counter_inc_blocked(struct btrfs_fs_info *fs_info)
1279{
1280	while (1) {
1281		percpu_counter_inc(&fs_info->dev_replace.bio_counter);
1282		if (likely(!test_bit(BTRFS_FS_STATE_DEV_REPLACING,
1283				     &fs_info->fs_state)))
1284			break;
1285
1286		btrfs_bio_counter_dec(fs_info);
1287		wait_event(fs_info->dev_replace.replace_wait,
1288			   !test_bit(BTRFS_FS_STATE_DEV_REPLACING,
1289				     &fs_info->fs_state));
1290	}
1291}