// SPDX-License-Identifier: GPL-2.0
#include "misc.h"
#include "ctree.h"
#include "block-group.h"
#include "space-info.h"
#include "disk-io.h"
#include "free-space-cache.h"
#include "free-space-tree.h"
#include "disk-io.h"
#include "volumes.h"
#include "transaction.h"
#include "ref-verify.h"
#include "sysfs.h"
#include "tree-log.h"
#include "delalloc-space.h"
/*
* Return target flags in extended format or 0 if restripe for this chunk_type
* is not in progress
*
* Should be called with balance_lock held
*/
static u64 get_restripe_target(struct btrfs_fs_info *fs_info, u64 flags)
{
struct btrfs_balance_control *bctl = fs_info->balance_ctl;
u64 target = 0;
if (!bctl)
return 0;
if (flags & BTRFS_BLOCK_GROUP_DATA &&
bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) {
target = BTRFS_BLOCK_GROUP_DATA | bctl->data.target;
} else if (flags & BTRFS_BLOCK_GROUP_SYSTEM &&
bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
target = BTRFS_BLOCK_GROUP_SYSTEM | bctl->sys.target;
} else if (flags & BTRFS_BLOCK_GROUP_METADATA &&
bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) {
target = BTRFS_BLOCK_GROUP_METADATA | bctl->meta.target;
}
return target;
}
/*
* @flags: available profiles in extended format (see ctree.h)
*
* Return reduced profile in chunk format. If profile changing is in progress
* (either running or paused) picks the target profile (if it's already
* available), otherwise falls back to plain reducing.
*/
static u64 btrfs_reduce_alloc_profile(struct btrfs_fs_info *fs_info, u64 flags)
{
u64 num_devices = fs_info->fs_devices->rw_devices;
u64 target;
u64 raid_type;
u64 allowed = 0;
/*
* See if restripe for this chunk_type is in progress, if so try to
* reduce to the target profile
*/
spin_lock(&fs_info->balance_lock);
target = get_restripe_target(fs_info, flags);
if (target) {
/* Pick target profile only if it's already available */
if ((flags & target) & BTRFS_EXTENDED_PROFILE_MASK) {
spin_unlock(&fs_info->balance_lock);
return extended_to_chunk(target);
}
}
spin_unlock(&fs_info->balance_lock);
/* First, mask out the RAID levels which aren't possible */
for (raid_type = 0; raid_type < BTRFS_NR_RAID_TYPES; raid_type++) {
if (num_devices >= btrfs_raid_array[raid_type].devs_min)
allowed |= btrfs_raid_array[raid_type].bg_flag;
}
allowed &= flags;
if (allowed & BTRFS_BLOCK_GROUP_RAID6)
allowed = BTRFS_BLOCK_GROUP_RAID6;
else if (allowed & BTRFS_BLOCK_GROUP_RAID5)
allowed = BTRFS_BLOCK_GROUP_RAID5;
else if (allowed & BTRFS_BLOCK_GROUP_RAID10)
allowed = BTRFS_BLOCK_GROUP_RAID10;
else if (allowed & BTRFS_BLOCK_GROUP_RAID1)
allowed = BTRFS_BLOCK_GROUP_RAID1;
else if (allowed & BTRFS_BLOCK_GROUP_RAID0)
allowed = BTRFS_BLOCK_GROUP_RAID0;
flags &= ~BTRFS_BLOCK_GROUP_PROFILE_MASK;
return extended_to_chunk(flags | allowed);
}
static u64 get_alloc_profile(struct btrfs_fs_info *fs_info, u64 orig_flags)
{
unsigned seq;
u64 flags;
do {
flags = orig_flags;
seq = read_seqbegin(&fs_info->profiles_lock);
if (flags & BTRFS_BLOCK_GROUP_DATA)
flags |= fs_info->avail_data_alloc_bits;
else if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
flags |= fs_info->avail_system_alloc_bits;
else if (flags & BTRFS_BLOCK_GROUP_METADATA)
flags |= fs_info->avail_metadata_alloc_bits;
} while (read_seqretry(&fs_info->profiles_lock, seq));
return btrfs_reduce_alloc_profile(fs_info, flags);
}
u64 btrfs_get_alloc_profile(struct btrfs_fs_info *fs_info, u64 orig_flags)
{
return get_alloc_profile(fs_info, orig_flags);
}
void btrfs_get_block_group(struct btrfs_block_group_cache *cache)
{
atomic_inc(&cache->count);
}
void btrfs_put_block_group(struct btrfs_block_group_cache *cache)
{
if (atomic_dec_and_test(&cache->count)) {
WARN_ON(cache->pinned > 0);
WARN_ON(cache->reserved > 0);
/*
* If not empty, someone is still holding mutex of
* full_stripe_lock, which can only be released by caller.
* And it will definitely cause use-after-free when caller
* tries to release full stripe lock.
*
* No better way to resolve, but only to warn.
*/
WARN_ON(!RB_EMPTY_ROOT(&cache->full_stripe_locks_root.root));
kfree(cache->free_space_ctl);
kfree(cache);
}
}
/*
* This adds the block group to the fs_info rb tree for the block group cache
*/
static int btrfs_add_block_group_cache(struct btrfs_fs_info *info,
struct btrfs_block_group_cache *block_group)
{
struct rb_node **p;
struct rb_node *parent = NULL;
struct btrfs_block_group_cache *cache;
spin_lock(&info->block_group_cache_lock);
p = &info->block_group_cache_tree.rb_node;
while (*p) {
parent = *p;
cache = rb_entry(parent, struct btrfs_block_group_cache,
cache_node);
if (block_group->key.objectid < cache->key.objectid) {
p = &(*p)->rb_left;
} else if (block_group->key.objectid > cache->key.objectid) {
p = &(*p)->rb_right;
} else {
spin_unlock(&info->block_group_cache_lock);
return -EEXIST;
}
}
rb_link_node(&block_group->cache_node, parent, p);
rb_insert_color(&block_group->cache_node,
&info->block_group_cache_tree);
if (info->first_logical_byte > block_group->key.objectid)
info->first_logical_byte = block_group->key.objectid;
spin_unlock(&info->block_group_cache_lock);
return 0;
}
/*
* This will return the block group at or after bytenr if contains is 0, else
* it will return the block group that contains the bytenr
*/
static struct btrfs_block_group_cache *block_group_cache_tree_search(
struct btrfs_fs_info *info, u64 bytenr, int contains)
{
struct btrfs_block_group_cache *cache, *ret = NULL;
struct rb_node *n;
u64 end, start;
spin_lock(&info->block_group_cache_lock);
n = info->block_group_cache_tree.rb_node;
while (n) {
cache = rb_entry(n, struct btrfs_block_group_cache,
cache_node);
end = cache->key.objectid + cache->key.offset - 1;
start = cache->key.objectid;
if (bytenr < start) {
if (!contains && (!ret || start < ret->key.objectid))
ret = cache;
n = n->rb_left;
} else if (bytenr > start) {
if (contains && bytenr <= end) {
ret = cache;
break;
}
n = n->rb_right;
} else {
ret = cache;
break;
}
}
if (ret) {
btrfs_get_block_group(ret);
if (bytenr == 0 && info->first_logical_byte > ret->key.objectid)
info->first_logical_byte = ret->key.objectid;
}
spin_unlock(&info->block_group_cache_lock);
return ret;
}
/*
* Return the block group that starts at or after bytenr
*/
struct btrfs_block_group_cache *btrfs_lookup_first_block_group(
struct btrfs_fs_info *info, u64 bytenr)
{
return block_group_cache_tree_search(info, bytenr, 0);
}
/*
* Return the block group that contains the given bytenr
*/
struct btrfs_block_group_cache *btrfs_lookup_block_group(
struct btrfs_fs_info *info, u64 bytenr)
{
return block_group_cache_tree_search(info, bytenr, 1);
}
struct btrfs_block_group_cache *btrfs_next_block_group(
struct btrfs_block_group_cache *cache)
{
struct btrfs_fs_info *fs_info = cache->fs_info;
struct rb_node *node;
spin_lock(&fs_info->block_group_cache_lock);
/* If our block group was removed, we need a full search. */
if (RB_EMPTY_NODE(&cache->cache_node)) {
const u64 next_bytenr = cache->key.objectid + cache->key.offset;
spin_unlock(&fs_info->block_group_cache_lock);
btrfs_put_block_group(cache);
cache = btrfs_lookup_first_block_group(fs_info, next_bytenr); return cache;
}
node = rb_next(&cache->cache_node);
btrfs_put_block_group(cache);
if (node) {
cache = rb_entry(node, struct btrfs_block_group_cache,
cache_node);
btrfs_get_block_group(cache);
} else
cache = NULL;
spin_unlock(&fs_info->block_group_cache_lock);
return cache;
}
bool btrfs_inc_nocow_writers(struct btrfs_fs_info *fs_info, u64 bytenr)
{
struct btrfs_block_group_cache *bg;
bool ret = true;
bg = btrfs_lookup_block_group(fs_info, bytenr);
if (!bg)
return false;
spin_lock(&bg->lock);
if (bg->ro)
ret = false;
else
atomic_inc(&bg->nocow_writers);
spin_unlock(&bg->lock);
/* No put on block group, done by btrfs_dec_nocow_writers */
if (!ret)
btrfs_put_block_group(bg);
return ret;
}
void btrfs_dec_nocow_writers(struct btrfs_fs_info *fs_info, u64 bytenr)
{
struct btrfs_block_group_cache *bg;
bg = btrfs_lookup_block_group(fs_info, bytenr);
ASSERT(bg);
if (atomic_dec_and_test(&bg->nocow_writers))
wake_up_var(&bg->nocow_writers);
/*
* Once for our lookup and once for the lookup done by a previous call
* to btrfs_inc_nocow_writers()
*/
btrfs_put_block_group(bg);
btrfs_put_block_group(bg);
}
void btrfs_wait_nocow_writers(struct btrfs_block_group_cache *bg)
{
wait_var_event(&bg->nocow_writers, !atomic_read(&bg->nocow_writers));
}
void btrfs_dec_block_group_reservations(struct btrfs_fs_info *fs_info,
const u64 start)
{
struct btrfs_block_group_cache *bg;
bg = btrfs_lookup_block_group(fs_info, start);
ASSERT(bg);
if (atomic_dec_and_test(&bg->reservations))
wake_up_var(&bg->reservations);
btrfs_put_block_group(bg);
}
void btrfs_wait_block_group_reservations(struct btrfs_block_group_cache *bg)
{
struct btrfs_space_info *space_info = bg->space_info;
ASSERT(bg->ro);
if (!(bg->flags & BTRFS_BLOCK_GROUP_DATA))
return;
/*
* Our block group is read only but before we set it to read only,
* some task might have had allocated an extent from it already, but it
* has not yet created a respective ordered extent (and added it to a
* root's list of ordered extents).
* Therefore wait for any task currently allocating extents, since the
* block group's reservations counter is incremented while a read lock
* on the groups' semaphore is held and decremented after releasing
* the read access on that semaphore and creating the ordered extent.
*/
down_write(&space_info->groups_sem);
up_write(&space_info->groups_sem);
wait_var_event(&bg->reservations, !atomic_read(&bg->reservations));
}
struct btrfs_caching_control *btrfs_get_caching_control(
struct btrfs_block_group_cache *cache)
{
struct btrfs_caching_control *ctl;
spin_lock(&cache->lock);
if (!cache->caching_ctl) {
spin_unlock(&cache->lock);
return NULL;
}
ctl = cache->caching_ctl;
refcount_inc(&ctl->count);
spin_unlock(&cache->lock);
return ctl;
}
void btrfs_put_caching_control(struct btrfs_caching_control *ctl)
{
if (refcount_dec_and_test(&ctl->count))
kfree(ctl);
}
/*
* When we wait for progress in the block group caching, its because our
* allocation attempt failed at least once. So, we must sleep and let some
* progress happen before we try again.
*
* This function will sleep at least once waiting for new free space to show
* up, and then it will check the block group free space numbers for our min
* num_bytes. Another option is to have it go ahead and look in the rbtree for
* a free extent of a given size, but this is a good start.
*
* Callers of this must check if cache->cached == BTRFS_CACHE_ERROR before using
* any of the information in this block group.
*/
void btrfs_wait_block_group_cache_progress(struct btrfs_block_group_cache *cache,
u64 num_bytes)
{
struct btrfs_caching_control *caching_ctl;
caching_ctl = btrfs_get_caching_control(cache);
if (!caching_ctl)
return;
wait_event(caching_ctl->wait, btrfs_block_group_cache_done(cache) ||
(cache->free_space_ctl->free_space >= num_bytes));
btrfs_put_caching_control(caching_ctl);
}
int btrfs_wait_block_group_cache_done(struct btrfs_block_group_cache *cache)
{
struct btrfs_caching_control *caching_ctl;
int ret = 0;
caching_ctl = btrfs_get_caching_control(cache);
if (!caching_ctl)
return (cache->cached == BTRFS_CACHE_ERROR) ? -EIO : 0;
wait_event(caching_ctl->wait, btrfs_block_group_cache_done(cache));
if (cache->cached == BTRFS_CACHE_ERROR)
ret = -EIO;
btrfs_put_caching_control(caching_ctl);
return ret;
}
#ifdef CONFIG_BTRFS_DEBUG
static void fragment_free_space(struct btrfs_block_group_cache *block_group)
{
struct btrfs_fs_info *fs_info = block_group->fs_info;
u64 start = block_group->key.objectid;
u64 len = block_group->key.offset;
u64 chunk = block_group->flags & BTRFS_BLOCK_GROUP_METADATA ?
fs_info->nodesize : fs_info->sectorsize;
u64 step = chunk << 1;
while (len > chunk) {
btrfs_remove_free_space(block_group, start, chunk);
start += step;
if (len < step)
len = 0;
else
len -= step;
}
}
#endif
/*
* This is only called by btrfs_cache_block_group, since we could have freed
* extents we need to check the pinned_extents for any extents that can't be
* used yet since their free space will be released as soon as the transaction
* commits.
*/
u64 add_new_free_space(struct btrfs_block_group_cache *block_group,
u64 start, u64 end)
{
struct btrfs_fs_info *info = block_group->fs_info;
u64 extent_start, extent_end, size, total_added = 0;
int ret;
while (start < end) {
ret = find_first_extent_bit(info->pinned_extents, start,
&extent_start, &extent_end,
EXTENT_DIRTY | EXTENT_UPTODATE,
NULL);
if (ret)
break;
if (extent_start <= start) {
start = extent_end + 1;
} else if (extent_start > start && extent_start < end) {
size = extent_start - start;
total_added += size;
ret = btrfs_add_free_space(block_group, start,
size);
BUG_ON(ret); /* -ENOMEM or logic error */
start = extent_end + 1;
} else {
break;
}
}
if (start < end) {
size = end - start;
total_added += size;
ret = btrfs_add_free_space(block_group, start, size);
BUG_ON(ret); /* -ENOMEM or logic error */
}
return total_added;
}
static int load_extent_tree_free(struct btrfs_caching_control *caching_ctl)
{
struct btrfs_block_group_cache *block_group = caching_ctl->block_group;
struct btrfs_fs_info *fs_info = block_group->fs_info;
struct btrfs_root *extent_root = fs_info->extent_root;
struct btrfs_path *path;
struct extent_buffer *leaf;
struct btrfs_key key;
u64 total_found = 0;
u64 last = 0;
u32 nritems;
int ret;
bool wakeup = true;
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
last = max_t(u64, block_group->key.objectid, BTRFS_SUPER_INFO_OFFSET);
#ifdef CONFIG_BTRFS_DEBUG
/*
* If we're fragmenting we don't want to make anybody think we can
* allocate from this block group until we've had a chance to fragment
* the free space.
*/
if (btrfs_should_fragment_free_space(block_group))
wakeup = false;
#endif
/*
* We don't want to deadlock with somebody trying to allocate a new
* extent for the extent root while also trying to search the extent
* root to add free space. So we skip locking and search the commit
* root, since its read-only
*/
path->skip_locking = 1;
path->search_commit_root = 1;
path->reada = READA_FORWARD;
key.objectid = last;
key.offset = 0;
key.type = BTRFS_EXTENT_ITEM_KEY;
next:
ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
if (ret < 0)
goto out;
leaf = path->nodes[0];
nritems = btrfs_header_nritems(leaf);
while (1) {
if (btrfs_fs_closing(fs_info) > 1) {
last = (u64)-1;
break;
}
if (path->slots[0] < nritems) {
btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
} else {
ret = btrfs_find_next_key(extent_root, path, &key, 0, 0);
if (ret)
break;
if (need_resched() ||
rwsem_is_contended(&fs_info->commit_root_sem)) {
if (wakeup)
caching_ctl->progress = last;
btrfs_release_path(path);
up_read(&fs_info->commit_root_sem);
mutex_unlock(&caching_ctl->mutex);
cond_resched();
mutex_lock(&caching_ctl->mutex);
down_read(&fs_info->commit_root_sem);
goto next;
}
ret = btrfs_next_leaf(extent_root, path);
if (ret < 0)
goto out;
if (ret)
break;
leaf = path->nodes[0];
nritems = btrfs_header_nritems(leaf);
continue;
}
if (key.objectid < last) {
key.objectid = last;
key.offset = 0;
key.type = BTRFS_EXTENT_ITEM_KEY;
if (wakeup)
caching_ctl->progress = last;
btrfs_release_path(path);
goto next;
}
if (key.objectid < block_group->key.objectid) {
path->slots[0]++;
continue;
}
if (key.objectid >= block_group->key.objectid +
block_group->key.offset)
break;
if (key.type == BTRFS_EXTENT_ITEM_KEY ||
key.type == BTRFS_METADATA_ITEM_KEY) {
total_found += add_new_free_space(block_group, last,
key.objectid);
if (key.type == BTRFS_METADATA_ITEM_KEY)
last = key.objectid +
fs_info->nodesize;
else
last = key.objectid + key.offset;
if (total_found > CACHING_CTL_WAKE_UP) {
total_found = 0;
if (wakeup)
wake_up(&caching_ctl->wait);
}
}
path->slots[0]++;
}
ret = 0;
total_found += add_new_free_space(block_group, last,
block_group->key.objectid +
block_group->key.offset);
caching_ctl->progress = (u64)-1;
out:
btrfs_free_path(path);
return ret;
}
static noinline void caching_thread(struct btrfs_work *work)
{
struct btrfs_block_group_cache *block_group;
struct btrfs_fs_info *fs_info;
struct btrfs_caching_control *caching_ctl;
int ret;
caching_ctl = container_of(work, struct btrfs_caching_control, work);
block_group = caching_ctl->block_group;
fs_info = block_group->fs_info;
mutex_lock(&caching_ctl->mutex);
down_read(&fs_info->commit_root_sem);
if (btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE))
ret = load_free_space_tree(caching_ctl);
else
ret = load_extent_tree_free(caching_ctl);
spin_lock(&block_group->lock);
block_group->caching_ctl = NULL;
block_group->cached = ret ? BTRFS_CACHE_ERROR : BTRFS_CACHE_FINISHED;
spin_unlock(&block_group->lock);
#ifdef CONFIG_BTRFS_DEBUG
if (btrfs_should_fragment_free_space(block_group)) {
u64 bytes_used;
spin_lock(&block_group->space_info->lock);
spin_lock(&block_group->lock);
bytes_used = block_group->key.offset -
btrfs_block_group_used(&block_group->item);
block_group->space_info->bytes_used += bytes_used >> 1;
spin_unlock(&block_group->lock);
spin_unlock(&block_group->space_info->lock);
fragment_free_space(block_group);
}
#endif
caching_ctl->progress = (u64)-1;
up_read(&fs_info->commit_root_sem);
btrfs_free_excluded_extents(block_group);
mutex_unlock(&caching_ctl->mutex);
wake_up(&caching_ctl->wait);
btrfs_put_caching_control(caching_ctl);
btrfs_put_block_group(block_group);
}
int btrfs_cache_block_group(struct btrfs_block_group_cache *cache,
int load_cache_only)
{
DEFINE_WAIT(wait);
struct btrfs_fs_info *fs_info = cache->fs_info;
struct btrfs_caching_control *caching_ctl;
int ret = 0;
caching_ctl = kzalloc(sizeof(*caching_ctl), GFP_NOFS);
if (!caching_ctl)
return -ENOMEM;
INIT_LIST_HEAD(&caching_ctl->list);
mutex_init(&caching_ctl->mutex);
init_waitqueue_head(&caching_ctl->wait);
caching_ctl->block_group = cache;
caching_ctl->progress = cache->key.objectid;
refcount_set(&caching_ctl->count, 1);
btrfs_init_work(&caching_ctl->work, caching_thread, NULL, NULL);
spin_lock(&cache->lock);
/*
* This should be a rare occasion, but this could happen I think in the
* case where one thread starts to load the space cache info, and then
* some other thread starts a transaction commit which tries to do an
* allocation while the other thread is still loading the space cache
* info. The previous loop should have kept us from choosing this block
* group, but if we've moved to the state where we will wait on caching
* block groups we need to first check if we're doing a fast load here,
* so we can wait for it to finish, otherwise we could end up allocating
* from a block group who's cache gets evicted for one reason or
* another.
*/
while (cache->cached == BTRFS_CACHE_FAST) {
struct btrfs_caching_control *ctl;
ctl = cache->caching_ctl;
refcount_inc(&ctl->count);
prepare_to_wait(&ctl->wait, &wait, TASK_UNINTERRUPTIBLE);
spin_unlock(&cache->lock);
schedule();
finish_wait(&ctl->wait, &wait);
btrfs_put_caching_control(ctl);
spin_lock(&cache->lock);
}
if (cache->cached != BTRFS_CACHE_NO) {
spin_unlock(&cache->lock);
kfree(caching_ctl);
return 0;
}
WARN_ON(cache->caching_ctl);
cache->caching_ctl = caching_ctl;
cache->cached = BTRFS_CACHE_FAST;
spin_unlock(&cache->lock);
if (btrfs_test_opt(fs_info, SPACE_CACHE)) {
mutex_lock(&caching_ctl->mutex);
ret = load_free_space_cache(cache);
spin_lock(&cache->lock);
if (ret == 1) {
cache->caching_ctl = NULL;
cache->cached = BTRFS_CACHE_FINISHED;
cache->last_byte_to_unpin = (u64)-1;
caching_ctl->progress = (u64)-1;
} else {
if (load_cache_only) {
cache->caching_ctl = NULL;
cache->cached = BTRFS_CACHE_NO;
} else {
cache->cached = BTRFS_CACHE_STARTED;
cache->has_caching_ctl = 1;
}
}
spin_unlock(&cache->lock);
#ifdef CONFIG_BTRFS_DEBUG
if (ret == 1 &&
btrfs_should_fragment_free_space(cache)) {
u64 bytes_used;
spin_lock(&cache->space_info->lock);
spin_lock(&cache->lock);
bytes_used = cache->key.offset -
btrfs_block_group_used(&cache->item);
cache->space_info->bytes_used += bytes_used >> 1;
spin_unlock(&cache->lock);
spin_unlock(&cache->space_info->lock);
fragment_free_space(cache);
}
#endif
mutex_unlock(&caching_ctl->mutex);
wake_up(&caching_ctl->wait);
if (ret == 1) {
btrfs_put_caching_control(caching_ctl);
btrfs_free_excluded_extents(cache);
return 0;
}
} else {
/*
* We're either using the free space tree or no caching at all.
* Set cached to the appropriate value and wakeup any waiters.
*/
spin_lock(&cache->lock);
if (load_cache_only) {
cache->caching_ctl = NULL;
cache->cached = BTRFS_CACHE_NO;
} else {
cache->cached = BTRFS_CACHE_STARTED;
cache->has_caching_ctl = 1;
}
spin_unlock(&cache->lock);
wake_up(&caching_ctl->wait);
}
if (load_cache_only) {
btrfs_put_caching_control(caching_ctl);
return 0;
}
down_write(&fs_info->commit_root_sem);
refcount_inc(&caching_ctl->count);
list_add_tail(&caching_ctl->list, &fs_info->caching_block_groups);
up_write(&fs_info->commit_root_sem);
btrfs_get_block_group(cache);
btrfs_queue_work(fs_info->caching_workers, &caching_ctl->work);
return ret;
}
static void clear_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
{
u64 extra_flags = chunk_to_extended(flags) &
BTRFS_EXTENDED_PROFILE_MASK;
write_seqlock(&fs_info->profiles_lock);
if (flags & BTRFS_BLOCK_GROUP_DATA)
fs_info->avail_data_alloc_bits &= ~extra_flags;
if (flags & BTRFS_BLOCK_GROUP_METADATA)
fs_info->avail_metadata_alloc_bits &= ~extra_flags;
if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
fs_info->avail_system_alloc_bits &= ~extra_flags;
write_sequnlock(&fs_info->profiles_lock);
}
/*
* Clear incompat bits for the following feature(s):
*
* - RAID56 - in case there's neither RAID5 nor RAID6 profile block group
* in the whole filesystem
*/
static void clear_incompat_bg_bits(struct btrfs_fs_info *fs_info, u64 flags)
{
if (flags & BTRFS_BLOCK_GROUP_RAID56_MASK) {
struct list_head *head = &fs_info->space_info;
struct btrfs_space_info *sinfo;
list_for_each_entry_rcu(sinfo, head, list) {
bool found = false;
down_read(&sinfo->groups_sem);
if (!list_empty(&sinfo->block_groups[BTRFS_RAID_RAID5]))
found = true;
if (!list_empty(&sinfo->block_groups[BTRFS_RAID_RAID6]))
found = true;
up_read(&sinfo->groups_sem);
if (found)
return;
}
btrfs_clear_fs_incompat(fs_info, RAID56);
}
}
int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
u64 group_start, struct extent_map *em)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
struct btrfs_root *root = fs_info->extent_root;
struct btrfs_path *path;
struct btrfs_block_group_cache *block_group;
struct btrfs_free_cluster *cluster;
struct btrfs_root *tree_root = fs_info->tree_root;
struct btrfs_key key;
struct inode *inode;
struct kobject *kobj = NULL;
int ret;
int index;
int factor;
struct btrfs_caching_control *caching_ctl = NULL;
bool remove_em;
bool remove_rsv = false;
block_group = btrfs_lookup_block_group(fs_info, group_start);
BUG_ON(!block_group);
BUG_ON(!block_group->ro);
trace_btrfs_remove_block_group(block_group);
/*
* Free the reserved super bytes from this block group before
* remove it.
*/
btrfs_free_excluded_extents(block_group);
btrfs_free_ref_tree_range(fs_info, block_group->key.objectid,
block_group->key.offset);
memcpy(&key, &block_group->key, sizeof(key));
index = btrfs_bg_flags_to_raid_index(block_group->flags);
factor = btrfs_bg_type_to_factor(block_group->flags);
/* make sure this block group isn't part of an allocation cluster */
cluster = &fs_info->data_alloc_cluster;
spin_lock(&cluster->refill_lock);
btrfs_return_cluster_to_free_space(block_group, cluster);
spin_unlock(&cluster->refill_lock);
/*
* make sure this block group isn't part of a metadata
* allocation cluster
*/
cluster = &fs_info->meta_alloc_cluster;
spin_lock(&cluster->refill_lock);
btrfs_return_cluster_to_free_space(block_group, cluster);
spin_unlock(&cluster->refill_lock);
path = btrfs_alloc_path();
if (!path) {
ret = -ENOMEM;
goto out;
}
/*
* get the inode first so any iput calls done for the io_list
* aren't the final iput (no unlinks allowed now)
*/
inode = lookup_free_space_inode(block_group, path);
mutex_lock(&trans->transaction->cache_write_mutex);
/*
* Make sure our free space cache IO is done before removing the
* free space inode
*/
spin_lock(&trans->transaction->dirty_bgs_lock);
if (!list_empty(&block_group->io_list)) {
list_del_init(&block_group->io_list);
WARN_ON(!IS_ERR(inode) && inode != block_group->io_ctl.inode);
spin_unlock(&trans->transaction->dirty_bgs_lock);
btrfs_wait_cache_io(trans, block_group, path);
btrfs_put_block_group(block_group);
spin_lock(&trans->transaction->dirty_bgs_lock);
}
if (!list_empty(&block_group->dirty_list)) {
list_del_init(&block_group->dirty_list);
remove_rsv = true;
btrfs_put_block_group(block_group);
}
spin_unlock(&trans->transaction->dirty_bgs_lock);
mutex_unlock(&trans->transaction->cache_write_mutex);
if (!IS_ERR(inode)) {
ret = btrfs_orphan_add(trans, BTRFS_I(inode));
if (ret) {
btrfs_add_delayed_iput(inode);
goto out;
}
clear_nlink(inode);
/* One for the block groups ref */
spin_lock(&block_group->lock);
if (block_group->iref) {
block_group->iref = 0;
block_group->inode = NULL;
spin_unlock(&block_group->lock);
iput(inode);
} else {
spin_unlock(&block_group->lock);
}
/* One for our lookup ref */
btrfs_add_delayed_iput(inode);
}
key.objectid = BTRFS_FREE_SPACE_OBJECTID;
key.offset = block_group->key.objectid;
key.type = 0;
ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
if (ret < 0)
goto out;
if (ret > 0)
btrfs_release_path(path);
if (ret == 0) {
ret = btrfs_del_item(trans, tree_root, path);
if (ret)
goto out;
btrfs_release_path(path);
}
spin_lock(&fs_info->block_group_cache_lock);
rb_erase(&block_group->cache_node,
&fs_info->block_group_cache_tree);
RB_CLEAR_NODE(&block_group->cache_node);
if (fs_info->first_logical_byte == block_group->key.objectid)
fs_info->first_logical_byte = (u64)-1;
spin_unlock(&fs_info->block_group_cache_lock);
down_write(&block_group->space_info->groups_sem);
/*
* we must use list_del_init so people can check to see if they
* are still on the list after taking the semaphore
*/
list_del_init(&block_group->list);
if (list_empty(&block_group->space_info->block_groups[index])) {
kobj = block_group->space_info->block_group_kobjs[index];
block_group->space_info->block_group_kobjs[index] = NULL;
clear_avail_alloc_bits(fs_info, block_group->flags);
}
up_write(&block_group->space_info->groups_sem);
clear_incompat_bg_bits(fs_info, block_group->flags);
if (kobj) {
kobject_del(kobj);
kobject_put(kobj);
}
if (block_group->has_caching_ctl)
caching_ctl = btrfs_get_caching_control(block_group);
if (block_group->cached == BTRFS_CACHE_STARTED)
btrfs_wait_block_group_cache_done(block_group);
if (block_group->has_caching_ctl) {
down_write(&fs_info->commit_root_sem);
if (!caching_ctl) {
struct btrfs_caching_control *ctl;
list_for_each_entry(ctl,
&fs_info->caching_block_groups, list)
if (ctl->block_group == block_group) {
caching_ctl = ctl;
refcount_inc(&caching_ctl->count);
break;
}
}
if (caching_ctl)
list_del_init(&caching_ctl->list);
up_write(&fs_info->commit_root_sem);
if (caching_ctl) {
/* Once for the caching bgs list and once for us. */
btrfs_put_caching_control(caching_ctl);
btrfs_put_caching_control(caching_ctl);
}
}
spin_lock(&trans->transaction->dirty_bgs_lock);
WARN_ON(!list_empty(&block_group->dirty_list));
WARN_ON(!list_empty(&block_group->io_list));
spin_unlock(&trans->transaction->dirty_bgs_lock);
btrfs_remove_free_space_cache(block_group);
spin_lock(&block_group->space_info->lock);
list_del_init(&block_group->ro_list);
if (btrfs_test_opt(fs_info, ENOSPC_DEBUG)) {
WARN_ON(block_group->space_info->total_bytes
< block_group->key.offset);
WARN_ON(block_group->space_info->bytes_readonly
< block_group->key.offset);
WARN_ON(block_group->space_info->disk_total
< block_group->key.offset * factor);
}
block_group->space_info->total_bytes -= block_group->key.offset;
block_group->space_info->bytes_readonly -= block_group->key.offset;
block_group->space_info->disk_total -= block_group->key.offset * factor;
spin_unlock(&block_group->space_info->lock);
memcpy(&key, &block_group->key, sizeof(key));
mutex_lock(&fs_info->chunk_mutex);
spin_lock(&block_group->lock);
block_group->removed = 1;
/*
* At this point trimming can't start on this block group, because we
* removed the block group from the tree fs_info->block_group_cache_tree
* so no one can't find it anymore and even if someone already got this
* block group before we removed it from the rbtree, they have already
* incremented block_group->trimming - if they didn't, they won't find
* any free space entries because we already removed them all when we
* called btrfs_remove_free_space_cache().
*
* And we must not remove the extent map from the fs_info->mapping_tree
* to prevent the same logical address range and physical device space
* ranges from being reused for a new block group. This is because our
* fs trim operation (btrfs_trim_fs() / btrfs_ioctl_fitrim()) is
* completely transactionless, so while it is trimming a range the
* currently running transaction might finish and a new one start,
* allowing for new block groups to be created that can reuse the same
* physical device locations unless we take this special care.
*
* There may also be an implicit trim operation if the file system
* is mounted with -odiscard. The same protections must remain
* in place until the extents have been discarded completely when
* the transaction commit has completed.
*/
remove_em = (atomic_read(&block_group->trimming) == 0);
spin_unlock(&block_group->lock);
mutex_unlock(&fs_info->chunk_mutex);
ret = remove_block_group_free_space(trans, block_group);
if (ret)
goto out;
btrfs_put_block_group(block_group);
btrfs_put_block_group(block_group);
ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
if (ret > 0)
ret = -EIO;
if (ret < 0)
goto out;
ret = btrfs_del_item(trans, root, path);
if (ret)
goto out;
if (remove_em) {
struct extent_map_tree *em_tree;
em_tree = &fs_info->mapping_tree;
write_lock(&em_tree->lock);
remove_extent_mapping(em_tree, em);
write_unlock(&em_tree->lock);
/* once for the tree */
free_extent_map(em);
}
out:
if (remove_rsv)
btrfs_delayed_refs_rsv_release(fs_info, 1);
btrfs_free_path(path);
return ret;
}
struct btrfs_trans_handle *btrfs_start_trans_remove_block_group(
struct btrfs_fs_info *fs_info, const u64 chunk_offset)
{
struct extent_map_tree *em_tree = &fs_info->mapping_tree;
struct extent_map *em;
struct map_lookup *map;
unsigned int num_items;
read_lock(&em_tree->lock);
em = lookup_extent_mapping(em_tree, chunk_offset, 1);
read_unlock(&em_tree->lock);
ASSERT(em && em->start == chunk_offset);
/*
* We need to reserve 3 + N units from the metadata space info in order
* to remove a block group (done at btrfs_remove_chunk() and at
* btrfs_remove_block_group()), which are used for:
*
* 1 unit for adding the free space inode's orphan (located in the tree
* of tree roots).
* 1 unit for deleting the block group item (located in the extent
* tree).
* 1 unit for deleting the free space item (located in tree of tree
* roots).
* N units for deleting N device extent items corresponding to each
* stripe (located in the device tree).
*
* In order to remove a block group we also need to reserve units in the
* system space info in order to update the chunk tree (update one or
* more device items and remove one chunk item), but this is done at
* btrfs_remove_chunk() through a call to check_system_chunk().
*/
map = em->map_lookup;
num_items = 3 + map->num_stripes;
free_extent_map(em);
return btrfs_start_transaction_fallback_global_rsv(fs_info->extent_root,
num_items, 1);
}
/*
* Mark block group @cache read-only, so later write won't happen to block
* group @cache.
*
* If @force is not set, this function will only mark the block group readonly
* if we have enough free space (1M) in other metadata/system block groups.
* If @force is not set, this function will mark the block group readonly
* without checking free space.
*
* NOTE: This function doesn't care if other block groups can contain all the
* data in this block group. That check should be done by relocation routine,
* not this function.
*/
static int inc_block_group_ro(struct btrfs_block_group_cache *cache, int force)
{
struct btrfs_space_info *sinfo = cache->space_info;
u64 num_bytes;
u64 sinfo_used;
u64 min_allocable_bytes;
int ret = -ENOSPC;
/*
* We need some metadata space and system metadata space for
* allocating chunks in some corner cases until we force to set
* it to be readonly.
*/
if ((sinfo->flags &
(BTRFS_BLOCK_GROUP_SYSTEM | BTRFS_BLOCK_GROUP_METADATA)) &&
!force)
min_allocable_bytes = SZ_1M;
else
min_allocable_bytes = 0;
spin_lock(&sinfo->lock);
spin_lock(&cache->lock);
if (cache->ro) {
cache->ro++;
ret = 0;
goto out;
}
num_bytes = cache->key.offset - cache->reserved - cache->pinned -
cache->bytes_super - btrfs_block_group_used(&cache->item);
sinfo_used = btrfs_space_info_used(sinfo, true);
/*
* sinfo_used + num_bytes should always <= sinfo->total_bytes.
*
* Here we make sure if we mark this bg RO, we still have enough
* free space as buffer (if min_allocable_bytes is not 0).
*/
if (sinfo_used + num_bytes + min_allocable_bytes <=
sinfo->total_bytes) {
sinfo->bytes_readonly += num_bytes;
cache->ro++;
list_add_tail(&cache->ro_list, &sinfo->ro_bgs);
ret = 0;
}
out:
spin_unlock(&cache->lock);
spin_unlock(&sinfo->lock);
if (ret == -ENOSPC && btrfs_test_opt(cache->fs_info, ENOSPC_DEBUG)) {
btrfs_info(cache->fs_info,
"unable to make block group %llu ro",
cache->key.objectid);
btrfs_info(cache->fs_info,
"sinfo_used=%llu bg_num_bytes=%llu min_allocable=%llu",
sinfo_used, num_bytes, min_allocable_bytes);
btrfs_dump_space_info(cache->fs_info, cache->space_info, 0, 0);
}
return ret;
}
/*
* Process the unused_bgs list and remove any that don't have any allocated
* space inside of them.
*/
void btrfs_delete_unused_bgs(struct btrfs_fs_info *fs_info)
{
struct btrfs_block_group_cache *block_group;
struct btrfs_space_info *space_info;
struct btrfs_trans_handle *trans;
int ret = 0;
if (!test_bit(BTRFS_FS_OPEN, &fs_info->flags))
return;
spin_lock(&fs_info->unused_bgs_lock);
while (!list_empty(&fs_info->unused_bgs)) {
u64 start, end;
int trimming;
block_group = list_first_entry(&fs_info->unused_bgs,
struct btrfs_block_group_cache,
bg_list);
list_del_init(&block_group->bg_list);
space_info = block_group->space_info;
if (ret || btrfs_mixed_space_info(space_info)) {
btrfs_put_block_group(block_group);
continue;
}
spin_unlock(&fs_info->unused_bgs_lock);
mutex_lock(&fs_info->delete_unused_bgs_mutex);
/* Don't want to race with allocators so take the groups_sem */
down_write(&space_info->groups_sem);
spin_lock(&block_group->lock);
if (block_group->reserved || block_group->pinned ||
btrfs_block_group_used(&block_group->item) ||
block_group->ro ||
list_is_singular(&block_group->list)) {
/*
* We want to bail if we made new allocations or have
* outstanding allocations in this block group. We do
* the ro check in case balance is currently acting on
* this block group.
*/
trace_btrfs_skip_unused_block_group(block_group);
spin_unlock(&block_group->lock);
up_write(&space_info->groups_sem);
goto next;
}
spin_unlock(&block_group->lock);
/* We don't want to force the issue, only flip if it's ok. */
ret = inc_block_group_ro(block_group, 0);
up_write(&space_info->groups_sem);
if (ret < 0) {
ret = 0;
goto next;
}
/*
* Want to do this before we do anything else so we can recover
* properly if we fail to join the transaction.
*/
trans = btrfs_start_trans_remove_block_group(fs_info,
block_group->key.objectid);
if (IS_ERR(trans)) {
btrfs_dec_block_group_ro(block_group);
ret = PTR_ERR(trans);
goto next;
}
/*
* We could have pending pinned extents for this block group,
* just delete them, we don't care about them anymore.
*/
start = block_group->key.objectid;
end = start + block_group->key.offset - 1;
/*
* Hold the unused_bg_unpin_mutex lock to avoid racing with
* btrfs_finish_extent_commit(). If we are at transaction N,
* another task might be running finish_extent_commit() for the
* previous transaction N - 1, and have seen a range belonging
* to the block group in freed_extents[] before we were able to
* clear the whole block group range from freed_extents[]. This
* means that task can lookup for the block group after we
* unpinned it from freed_extents[] and removed it, leading to
* a BUG_ON() at btrfs_unpin_extent_range().
*/
mutex_lock(&fs_info->unused_bg_unpin_mutex);
ret = clear_extent_bits(&fs_info->freed_extents[0], start, end,
EXTENT_DIRTY);
if (ret) {
mutex_unlock(&fs_info->unused_bg_unpin_mutex);
btrfs_dec_block_group_ro(block_group);
goto end_trans;
}
ret = clear_extent_bits(&fs_info->freed_extents[1], start, end,
EXTENT_DIRTY);
if (ret) {
mutex_unlock(&fs_info->unused_bg_unpin_mutex);
btrfs_dec_block_group_ro(block_group);
goto end_trans;
}
mutex_unlock(&fs_info->unused_bg_unpin_mutex);
/* Reset pinned so btrfs_put_block_group doesn't complain */
spin_lock(&space_info->lock);
spin_lock(&block_group->lock);
btrfs_space_info_update_bytes_pinned(fs_info, space_info,
-block_group->pinned);
space_info->bytes_readonly += block_group->pinned;
percpu_counter_add_batch(&space_info->total_bytes_pinned,
-block_group->pinned,
BTRFS_TOTAL_BYTES_PINNED_BATCH);
block_group->pinned = 0;
spin_unlock(&block_group->lock);
spin_unlock(&space_info->lock);
/* DISCARD can flip during remount */
trimming = btrfs_test_opt(fs_info, DISCARD);
/* Implicit trim during transaction commit. */
if (trimming)
btrfs_get_block_group_trimming(block_group);
/*
* Btrfs_remove_chunk will abort the transaction if things go
* horribly wrong.
*/
ret = btrfs_remove_chunk(trans, block_group->key.objectid);
if (ret) {
if (trimming)
btrfs_put_block_group_trimming(block_group);
goto end_trans;
}
/*
* If we're not mounted with -odiscard, we can just forget
* about this block group. Otherwise we'll need to wait
* until transaction commit to do the actual discard.
*/
if (trimming) {
spin_lock(&fs_info->unused_bgs_lock);
/*
* A concurrent scrub might have added us to the list
* fs_info->unused_bgs, so use a list_move operation
* to add the block group to the deleted_bgs list.
*/
list_move(&block_group->bg_list,
&trans->transaction->deleted_bgs);
spin_unlock(&fs_info->unused_bgs_lock);
btrfs_get_block_group(block_group);
}
end_trans:
btrfs_end_transaction(trans);
next:
mutex_unlock(&fs_info->delete_unused_bgs_mutex);
btrfs_put_block_group(block_group);
spin_lock(&fs_info->unused_bgs_lock);
}
spin_unlock(&fs_info->unused_bgs_lock);
}
void btrfs_mark_bg_unused(struct btrfs_block_group_cache *bg)
{
struct btrfs_fs_info *fs_info = bg->fs_info;
spin_lock(&fs_info->unused_bgs_lock);
if (list_empty(&bg->bg_list)) {
btrfs_get_block_group(bg);
trace_btrfs_add_unused_block_group(bg);
list_add_tail(&bg->bg_list, &fs_info->unused_bgs);
}
spin_unlock(&fs_info->unused_bgs_lock);
}
static int find_first_block_group(struct btrfs_fs_info *fs_info,
struct btrfs_path *path,
struct btrfs_key *key)
{
struct btrfs_root *root = fs_info->extent_root;
int ret = 0;
struct btrfs_key found_key;
struct extent_buffer *leaf;
struct btrfs_block_group_item bg;
u64 flags;
int slot;
ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
if (ret < 0)
goto out;
while (1) {
slot = path->slots[0];
leaf = path->nodes[0];
if (slot >= btrfs_header_nritems(leaf)) {
ret = btrfs_next_leaf(root, path);
if (ret == 0)
continue;
if (ret < 0)
goto out;
break;
}
btrfs_item_key_to_cpu(leaf, &found_key, slot);
if (found_key.objectid >= key->objectid &&
found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
struct extent_map_tree *em_tree;
struct extent_map *em;
em_tree = &root->fs_info->mapping_tree;
read_lock(&em_tree->lock);
em = lookup_extent_mapping(em_tree, found_key.objectid,
found_key.offset);
read_unlock(&em_tree->lock);
if (!em) {
btrfs_err(fs_info,
"logical %llu len %llu found bg but no related chunk",
found_key.objectid, found_key.offset);
ret = -ENOENT;
} else if (em->start != found_key.objectid ||
em->len != found_key.offset) {
btrfs_err(fs_info,
"block group %llu len %llu mismatch with chunk %llu len %llu",
found_key.objectid, found_key.offset,
em->start, em->len);
ret = -EUCLEAN;
} else {
read_extent_buffer(leaf, &bg,
btrfs_item_ptr_offset(leaf, slot),
sizeof(bg));
flags = btrfs_block_group_flags(&bg) &
BTRFS_BLOCK_GROUP_TYPE_MASK;
if (flags != (em->map_lookup->type &
BTRFS_BLOCK_GROUP_TYPE_MASK)) {
btrfs_err(fs_info,
"block group %llu len %llu type flags 0x%llx mismatch with chunk type flags 0x%llx",
found_key.objectid,
found_key.offset, flags,
(BTRFS_BLOCK_GROUP_TYPE_MASK &
em->map_lookup->type));
ret = -EUCLEAN;
} else {
ret = 0;
}
}
free_extent_map(em);
goto out;
}
path->slots[0]++;
}
out:
return ret;
}
static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
{
u64 extra_flags = chunk_to_extended(flags) &
BTRFS_EXTENDED_PROFILE_MASK;
write_seqlock(&fs_info->profiles_lock);
if (flags & BTRFS_BLOCK_GROUP_DATA)
fs_info->avail_data_alloc_bits |= extra_flags;
if (flags & BTRFS_BLOCK_GROUP_METADATA)
fs_info->avail_metadata_alloc_bits |= extra_flags;
if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
fs_info->avail_system_alloc_bits |= extra_flags;
write_sequnlock(&fs_info->profiles_lock);
}
static int exclude_super_stripes(struct btrfs_block_group_cache *cache)
{
struct btrfs_fs_info *fs_info = cache->fs_info;
u64 bytenr;
u64 *logical;
int stripe_len;
int i, nr, ret;
if (cache->key.objectid < BTRFS_SUPER_INFO_OFFSET) {
stripe_len = BTRFS_SUPER_INFO_OFFSET - cache->key.objectid;
cache->bytes_super += stripe_len;
ret = btrfs_add_excluded_extent(fs_info, cache->key.objectid,
stripe_len);
if (ret)
return ret;
}
for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
bytenr = btrfs_sb_offset(i);
ret = btrfs_rmap_block(fs_info, cache->key.objectid,
bytenr, &logical, &nr, &stripe_len);
if (ret)
return ret;
while (nr--) {
u64 start, len;
if (logical[nr] > cache->key.objectid +
cache->key.offset)
continue;
if (logical[nr] + stripe_len <= cache->key.objectid)
continue;
start = logical[nr];
if (start < cache->key.objectid) {
start = cache->key.objectid;
len = (logical[nr] + stripe_len) - start;
} else {
len = min_t(u64, stripe_len,
cache->key.objectid +
cache->key.offset - start);
}
cache->bytes_super += len;
ret = btrfs_add_excluded_extent(fs_info, start, len);
if (ret) {
kfree(logical);
return ret;
}
}
kfree(logical);
}
return 0;
}
static void link_block_group(struct btrfs_block_group_cache *cache)
{
struct btrfs_space_info *space_info = cache->space_info;
int index = btrfs_bg_flags_to_raid_index(cache->flags);
bool first = false;
down_write(&space_info->groups_sem);
if (list_empty(&space_info->block_groups[index]))
first = true;
list_add_tail(&cache->list, &space_info->block_groups[index]);
up_write(&space_info->groups_sem);
if (first)
btrfs_sysfs_add_block_group_type(cache);
}
static struct btrfs_block_group_cache *btrfs_create_block_group_cache(
struct btrfs_fs_info *fs_info, u64 start, u64 size)
{
struct btrfs_block_group_cache *cache;
cache = kzalloc(sizeof(*cache), GFP_NOFS);
if (!cache)
return NULL;
cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
GFP_NOFS);
if (!cache->free_space_ctl) {
kfree(cache);
return NULL;
}
cache->key.objectid = start;
cache->key.offset = size;
cache->key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
cache->fs_info = fs_info;
cache->full_stripe_len = btrfs_full_stripe_len(fs_info, start);
set_free_space_tree_thresholds(cache);
atomic_set(&cache->count, 1);
spin_lock_init(&cache->lock);
init_rwsem(&cache->data_rwsem);
INIT_LIST_HEAD(&cache->list);
INIT_LIST_HEAD(&cache->cluster_list);
INIT_LIST_HEAD(&cache->bg_list);
INIT_LIST_HEAD(&cache->ro_list);
INIT_LIST_HEAD(&cache->dirty_list);
INIT_LIST_HEAD(&cache->io_list);
btrfs_init_free_space_ctl(cache);
atomic_set(&cache->trimming, 0);
mutex_init(&cache->free_space_lock);
btrfs_init_full_stripe_locks_tree(&cache->full_stripe_locks_root);
return cache;
}
/*
* Iterate all chunks and verify that each of them has the corresponding block
* group
*/
static int check_chunk_block_group_mappings(struct btrfs_fs_info *fs_info)
{
struct extent_map_tree *map_tree = &fs_info->mapping_tree;
struct extent_map *em;
struct btrfs_block_group_cache *bg;
u64 start = 0;
int ret = 0;
while (1) {
read_lock(&map_tree->lock);
/*
* lookup_extent_mapping will return the first extent map
* intersecting the range, so setting @len to 1 is enough to
* get the first chunk.
*/
em = lookup_extent_mapping(map_tree, start, 1);
read_unlock(&map_tree->lock);
if (!em)
break;
bg = btrfs_lookup_block_group(fs_info, em->start);
if (!bg) {
btrfs_err(fs_info,
"chunk start=%llu len=%llu doesn't have corresponding block group",
em->start, em->len);
ret = -EUCLEAN;
free_extent_map(em);
break;
}
if (bg->key.objectid != em->start ||
bg->key.offset != em->len ||
(bg->flags & BTRFS_BLOCK_GROUP_TYPE_MASK) !=
(em->map_lookup->type & BTRFS_BLOCK_GROUP_TYPE_MASK)) {
btrfs_err(fs_info,
"chunk start=%llu len=%llu flags=0x%llx doesn't match block group start=%llu len=%llu flags=0x%llx",
em->start, em->len,
em->map_lookup->type & BTRFS_BLOCK_GROUP_TYPE_MASK,
bg->key.objectid, bg->key.offset,
bg->flags & BTRFS_BLOCK_GROUP_TYPE_MASK);
ret = -EUCLEAN;
free_extent_map(em);
btrfs_put_block_group(bg);
break;
}
start = em->start + em->len;
free_extent_map(em);
btrfs_put_block_group(bg);
}
return ret;
}
int btrfs_read_block_groups(struct btrfs_fs_info *info)
{
struct btrfs_path *path;
int ret;
struct btrfs_block_group_cache *cache;
struct btrfs_space_info *space_info;
struct btrfs_key key;
struct btrfs_key found_key;
struct extent_buffer *leaf;
int need_clear = 0;
u64 cache_gen;
u64 feature;
int mixed;
feature = btrfs_super_incompat_flags(info->super_copy);
mixed = !!(feature & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS);
key.objectid = 0;
key.offset = 0;
key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
path->reada = READA_FORWARD;
cache_gen = btrfs_super_cache_generation(info->super_copy);
if (btrfs_test_opt(info, SPACE_CACHE) &&
btrfs_super_generation(info->super_copy) != cache_gen)
need_clear = 1;
if (btrfs_test_opt(info, CLEAR_CACHE))
need_clear = 1;
while (1) {
ret = find_first_block_group(info, path, &key);
if (ret > 0)
break;
if (ret != 0)
goto error;
leaf = path->nodes[0];
btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
cache = btrfs_create_block_group_cache(info, found_key.objectid,
found_key.offset);
if (!cache) {
ret = -ENOMEM;
goto error;
}
if (need_clear) {
/*
* When we mount with old space cache, we need to
* set BTRFS_DC_CLEAR and set dirty flag.
*
* a) Setting 'BTRFS_DC_CLEAR' makes sure that we
* truncate the old free space cache inode and
* setup a new one.
* b) Setting 'dirty flag' makes sure that we flush
* the new space cache info onto disk.
*/
if (btrfs_test_opt(info, SPACE_CACHE))
cache->disk_cache_state = BTRFS_DC_CLEAR;
}
read_extent_buffer(leaf, &cache->item,
btrfs_item_ptr_offset(leaf, path->slots[0]),
sizeof(cache->item));
cache->flags = btrfs_block_group_flags(&cache->item);
if (!mixed &&
((cache->flags & BTRFS_BLOCK_GROUP_METADATA) &&
(cache->flags & BTRFS_BLOCK_GROUP_DATA))) {
btrfs_err(info,
"bg %llu is a mixed block group but filesystem hasn't enabled mixed block groups",
cache->key.objectid);
btrfs_put_block_group(cache);
ret = -EINVAL;
goto error;
}
key.objectid = found_key.objectid + found_key.offset;
btrfs_release_path(path);
/*
* We need to exclude the super stripes now so that the space
* info has super bytes accounted for, otherwise we'll think
* we have more space than we actually do.
*/
ret = exclude_super_stripes(cache);
if (ret) {
/*
* We may have excluded something, so call this just in
* case.
*/
btrfs_free_excluded_extents(cache);
btrfs_put_block_group(cache);
goto error;
}
/*
* Check for two cases, either we are full, and therefore
* don't need to bother with the caching work since we won't
* find any space, or we are empty, and we can just add all
* the space in and be done with it. This saves us _a_lot_ of
* time, particularly in the full case.
*/
if (found_key.offset == btrfs_block_group_used(&cache->item)) {
cache->last_byte_to_unpin = (u64)-1;
cache->cached = BTRFS_CACHE_FINISHED;
btrfs_free_excluded_extents(cache);
} else if (btrfs_block_group_used(&cache->item) == 0) {
cache->last_byte_to_unpin = (u64)-1;
cache->cached = BTRFS_CACHE_FINISHED;
add_new_free_space(cache, found_key.objectid,
found_key.objectid +
found_key.offset);
btrfs_free_excluded_extents(cache);
}
ret = btrfs_add_block_group_cache(info, cache);
if (ret) {
btrfs_remove_free_space_cache(cache);
btrfs_put_block_group(cache);
goto error;
}
trace_btrfs_add_block_group(info, cache, 0);
btrfs_update_space_info(info, cache->flags, found_key.offset,
btrfs_block_group_used(&cache->item),
cache->bytes_super, &space_info);
cache->space_info = space_info;
link_block_group(cache);
set_avail_alloc_bits(info, cache->flags);
if (btrfs_chunk_readonly(info, cache->key.objectid)) {
inc_block_group_ro(cache, 1);
} else if (btrfs_block_group_used(&cache->item) == 0) {
ASSERT(list_empty(&cache->bg_list));
btrfs_mark_bg_unused(cache);
}
}
list_for_each_entry_rcu(space_info, &info->space_info, list) {
if (!(btrfs_get_alloc_profile(info, space_info->flags) &
(BTRFS_BLOCK_GROUP_RAID10 |
BTRFS_BLOCK_GROUP_RAID1_MASK |
BTRFS_BLOCK_GROUP_RAID56_MASK |
BTRFS_BLOCK_GROUP_DUP)))
continue;
/*
* Avoid allocating from un-mirrored block group if there are
* mirrored block groups.
*/
list_for_each_entry(cache,
&space_info->block_groups[BTRFS_RAID_RAID0],
list)
inc_block_group_ro(cache, 1);
list_for_each_entry(cache,
&space_info->block_groups[BTRFS_RAID_SINGLE],
list)
inc_block_group_ro(cache, 1);
}
btrfs_init_global_block_rsv(info);
ret = check_chunk_block_group_mappings(info);
error:
btrfs_free_path(path);
return ret;
}
void btrfs_create_pending_block_groups(struct btrfs_trans_handle *trans)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
struct btrfs_block_group_cache *block_group;
struct btrfs_root *extent_root = fs_info->extent_root;
struct btrfs_block_group_item item;
struct btrfs_key key;
int ret = 0;
if (!trans->can_flush_pending_bgs)
return;
while (!list_empty(&trans->new_bgs)) {
block_group = list_first_entry(&trans->new_bgs,
struct btrfs_block_group_cache,
bg_list);
if (ret)
goto next;
spin_lock(&block_group->lock);
memcpy(&item, &block_group->item, sizeof(item));
memcpy(&key, &block_group->key, sizeof(key));
spin_unlock(&block_group->lock);
ret = btrfs_insert_item(trans, extent_root, &key, &item,
sizeof(item));
if (ret)
btrfs_abort_transaction(trans, ret);
ret = btrfs_finish_chunk_alloc(trans, key.objectid, key.offset);
if (ret)
btrfs_abort_transaction(trans, ret);
add_block_group_free_space(trans, block_group);
/* Already aborted the transaction if it failed. */
next:
btrfs_delayed_refs_rsv_release(fs_info, 1);
list_del_init(&block_group->bg_list);
}
btrfs_trans_release_chunk_metadata(trans);
}
int btrfs_make_block_group(struct btrfs_trans_handle *trans, u64 bytes_used,
u64 type, u64 chunk_offset, u64 size)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
struct btrfs_block_group_cache *cache;
int ret;
btrfs_set_log_full_commit(trans);
cache = btrfs_create_block_group_cache(fs_info, chunk_offset, size);
if (!cache)
return -ENOMEM;
btrfs_set_block_group_used(&cache->item, bytes_used);
btrfs_set_block_group_chunk_objectid(&cache->item,
BTRFS_FIRST_CHUNK_TREE_OBJECTID);
btrfs_set_block_group_flags(&cache->item, type);
cache->flags = type;
cache->last_byte_to_unpin = (u64)-1;
cache->cached = BTRFS_CACHE_FINISHED;
cache->needs_free_space = 1;
ret = exclude_super_stripes(cache);
if (ret) {
/* We may have excluded something, so call this just in case */
btrfs_free_excluded_extents(cache);
btrfs_put_block_group(cache);
return ret;
}
add_new_free_space(cache, chunk_offset, chunk_offset + size);
btrfs_free_excluded_extents(cache);
#ifdef CONFIG_BTRFS_DEBUG
if (btrfs_should_fragment_free_space(cache)) {
u64 new_bytes_used = size - bytes_used;
bytes_used += new_bytes_used >> 1;
fragment_free_space(cache);
}
#endif
/*
* Ensure the corresponding space_info object is created and
* assigned to our block group. We want our bg to be added to the rbtree
* with its ->space_info set.
*/
cache->space_info = btrfs_find_space_info(fs_info, cache->flags);
ASSERT(cache->space_info);
ret = btrfs_add_block_group_cache(fs_info, cache);
if (ret) {
btrfs_remove_free_space_cache(cache);
btrfs_put_block_group(cache);
return ret;
}
/*
* Now that our block group has its ->space_info set and is inserted in
* the rbtree, update the space info's counters.
*/
trace_btrfs_add_block_group(fs_info, cache, 1);
btrfs_update_space_info(fs_info, cache->flags, size, bytes_used,
cache->bytes_super, &cache->space_info);
btrfs_update_global_block_rsv(fs_info);
link_block_group(cache);
list_add_tail(&cache->bg_list, &trans->new_bgs);
trans->delayed_ref_updates++;
btrfs_update_delayed_refs_rsv(trans);
set_avail_alloc_bits(fs_info, type);
return 0;
}
static u64 update_block_group_flags(struct btrfs_fs_info *fs_info, u64 flags)
{
u64 num_devices;
u64 stripped;
/*
* if restripe for this chunk_type is on pick target profile and
* return, otherwise do the usual balance
*/
stripped = get_restripe_target(fs_info, flags);
if (stripped)
return extended_to_chunk(stripped);
num_devices = fs_info->fs_devices->rw_devices;
stripped = BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID56_MASK |
BTRFS_BLOCK_GROUP_RAID1_MASK | BTRFS_BLOCK_GROUP_RAID10;
if (num_devices == 1) {
stripped |= BTRFS_BLOCK_GROUP_DUP;
stripped = flags & ~stripped;
/* turn raid0 into single device chunks */
if (flags & BTRFS_BLOCK_GROUP_RAID0)
return stripped;
/* turn mirroring into duplication */
if (flags & (BTRFS_BLOCK_GROUP_RAID1_MASK |
BTRFS_BLOCK_GROUP_RAID10))
return stripped | BTRFS_BLOCK_GROUP_DUP;
} else {
/* they already had raid on here, just return */
if (flags & stripped)
return flags;
stripped |= BTRFS_BLOCK_GROUP_DUP;
stripped = flags & ~stripped;
/* switch duplicated blocks with raid1 */
if (flags & BTRFS_BLOCK_GROUP_DUP)
return stripped | BTRFS_BLOCK_GROUP_RAID1;
/* this is drive concat, leave it alone */
}
return flags;
}
int btrfs_inc_block_group_ro(struct btrfs_block_group_cache *cache)
{
struct btrfs_fs_info *fs_info = cache->fs_info;
struct btrfs_trans_handle *trans;
u64 alloc_flags;
int ret;
again:
trans = btrfs_join_transaction(fs_info->extent_root);
if (IS_ERR(trans))
return PTR_ERR(trans);
/*
* we're not allowed to set block groups readonly after the dirty
* block groups cache has started writing. If it already started,
* back off and let this transaction commit
*/
mutex_lock(&fs_info->ro_block_group_mutex);
if (test_bit(BTRFS_TRANS_DIRTY_BG_RUN, &trans->transaction->flags)) {
u64 transid = trans->transid;
mutex_unlock(&fs_info->ro_block_group_mutex);
btrfs_end_transaction(trans);
ret = btrfs_wait_for_commit(fs_info, transid);
if (ret)
return ret;
goto again;
}
/*
* if we are changing raid levels, try to allocate a corresponding
* block group with the new raid level.
*/
alloc_flags = update_block_group_flags(fs_info, cache->flags);
if (alloc_flags != cache->flags) {
ret = btrfs_chunk_alloc(trans, alloc_flags, CHUNK_ALLOC_FORCE);
/*
* ENOSPC is allowed here, we may have enough space
* already allocated at the new raid level to
* carry on
*/
if (ret == -ENOSPC)
ret = 0;
if (ret < 0)
goto out;
}
ret = inc_block_group_ro(cache, 0);
if (!ret)
goto out;
alloc_flags = btrfs_get_alloc_profile(fs_info, cache->space_info->flags);
ret = btrfs_chunk_alloc(trans, alloc_flags, CHUNK_ALLOC_FORCE);
if (ret < 0)
goto out;
ret = inc_block_group_ro(cache, 0);
out:
if (cache->flags & BTRFS_BLOCK_GROUP_SYSTEM) {
alloc_flags = update_block_group_flags(fs_info, cache->flags);
mutex_lock(&fs_info->chunk_mutex);
check_system_chunk(trans, alloc_flags);
mutex_unlock(&fs_info->chunk_mutex);
}
mutex_unlock(&fs_info->ro_block_group_mutex);
btrfs_end_transaction(trans);
return ret;
}
void btrfs_dec_block_group_ro(struct btrfs_block_group_cache *cache)
{
struct btrfs_space_info *sinfo = cache->space_info;
u64 num_bytes;
BUG_ON(!cache->ro);
spin_lock(&sinfo->lock);
spin_lock(&cache->lock);
if (!--cache->ro) {
num_bytes = cache->key.offset - cache->reserved -
cache->pinned - cache->bytes_super -
btrfs_block_group_used(&cache->item);
sinfo->bytes_readonly -= num_bytes;
list_del_init(&cache->ro_list);
}
spin_unlock(&cache->lock);
spin_unlock(&sinfo->lock);
}
static int write_one_cache_group(struct btrfs_trans_handle *trans,
struct btrfs_path *path,
struct btrfs_block_group_cache *cache)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
int ret;
struct btrfs_root *extent_root = fs_info->extent_root;
unsigned long bi;
struct extent_buffer *leaf;
ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
if (ret) {
if (ret > 0)
ret = -ENOENT;
goto fail;
}
leaf = path->nodes[0];
bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item));
btrfs_mark_buffer_dirty(leaf);
fail:
btrfs_release_path(path);
return ret;
}
static int cache_save_setup(struct btrfs_block_group_cache *block_group,
struct btrfs_trans_handle *trans,
struct btrfs_path *path)
{
struct btrfs_fs_info *fs_info = block_group->fs_info;
struct btrfs_root *root = fs_info->tree_root;
struct inode *inode = NULL;
struct extent_changeset *data_reserved = NULL;
u64 alloc_hint = 0;
int dcs = BTRFS_DC_ERROR;
u64 num_pages = 0;
int retries = 0;
int ret = 0;
/*
* If this block group is smaller than 100 megs don't bother caching the
* block group.
*/
if (block_group->key.offset < (100 * SZ_1M)) {
spin_lock(&block_group->lock);
block_group->disk_cache_state = BTRFS_DC_WRITTEN;
spin_unlock(&block_group->lock);
return 0;
}
if (trans->aborted)
return 0;
again:
inode = lookup_free_space_inode(block_group, path);
if (IS_ERR(inode) && PTR_ERR(inode) != -ENOENT) {
ret = PTR_ERR(inode);
btrfs_release_path(path);
goto out;
}
if (IS_ERR(inode)) {
BUG_ON(retries);
retries++;
if (block_group->ro)
goto out_free;
ret = create_free_space_inode(trans, block_group, path);
if (ret)
goto out_free;
goto again;
}
/*
* We want to set the generation to 0, that way if anything goes wrong
* from here on out we know not to trust this cache when we load up next
* time.
*/
BTRFS_I(inode)->generation = 0;
ret = btrfs_update_inode(trans, root, inode);
if (ret) {
/*
* So theoretically we could recover from this, simply set the
* super cache generation to 0 so we know to invalidate the
* cache, but then we'd have to keep track of the block groups
* that fail this way so we know we _have_ to reset this cache
* before the next commit or risk reading stale cache. So to
* limit our exposure to horrible edge cases lets just abort the
* transaction, this only happens in really bad situations
* anyway.
*/
btrfs_abort_transaction(trans, ret);
goto out_put;
}
WARN_ON(ret);
/* We've already setup this transaction, go ahead and exit */
if (block_group->cache_generation == trans->transid &&
i_size_read(inode)) {
dcs = BTRFS_DC_SETUP;
goto out_put;
}
if (i_size_read(inode) > 0) {
ret = btrfs_check_trunc_cache_free_space(fs_info,
&fs_info->global_block_rsv);
if (ret)
goto out_put;
ret = btrfs_truncate_free_space_cache(trans, NULL, inode);
if (ret)
goto out_put;
}
spin_lock(&block_group->lock);
if (block_group->cached != BTRFS_CACHE_FINISHED ||
!btrfs_test_opt(fs_info, SPACE_CACHE)) {
/*
* don't bother trying to write stuff out _if_
* a) we're not cached,
* b) we're with nospace_cache mount option,
* c) we're with v2 space_cache (FREE_SPACE_TREE).
*/
dcs = BTRFS_DC_WRITTEN;
spin_unlock(&block_group->lock);
goto out_put;
}
spin_unlock(&block_group->lock);
/*
* We hit an ENOSPC when setting up the cache in this transaction, just
* skip doing the setup, we've already cleared the cache so we're safe.
*/
if (test_bit(BTRFS_TRANS_CACHE_ENOSPC, &trans->transaction->flags)) {
ret = -ENOSPC;
goto out_put;
}
/*
* Try to preallocate enough space based on how big the block group is.
* Keep in mind this has to include any pinned space which could end up
* taking up quite a bit since it's not folded into the other space
* cache.
*/
num_pages = div_u64(block_group->key.offset, SZ_256M);
if (!num_pages)
num_pages = 1;
num_pages *= 16;
num_pages *= PAGE_SIZE;
ret = btrfs_check_data_free_space(inode, &data_reserved, 0, num_pages);
if (ret)
goto out_put;
ret = btrfs_prealloc_file_range_trans(inode, trans, 0, 0, num_pages,
num_pages, num_pages,
&alloc_hint);
/*
* Our cache requires contiguous chunks so that we don't modify a bunch
* of metadata or split extents when writing the cache out, which means
* we can enospc if we are heavily fragmented in addition to just normal
* out of space conditions. So if we hit this just skip setting up any
* other block groups for this transaction, maybe we'll unpin enough
* space the next time around.
*/
if (!ret)
dcs = BTRFS_DC_SETUP;
else if (ret == -ENOSPC)
set_bit(BTRFS_TRANS_CACHE_ENOSPC, &trans->transaction->flags);
out_put:
iput(inode);
out_free:
btrfs_release_path(path);
out:
spin_lock(&block_group->lock);
if (!ret && dcs == BTRFS_DC_SETUP)
block_group->cache_generation = trans->transid;
block_group->disk_cache_state = dcs;
spin_unlock(&block_group->lock);
extent_changeset_free(data_reserved);
return ret;
}
int btrfs_setup_space_cache(struct btrfs_trans_handle *trans)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
struct btrfs_block_group_cache *cache, *tmp;
struct btrfs_transaction *cur_trans = trans->transaction;
struct btrfs_path *path;
if (list_empty(&cur_trans->dirty_bgs) ||
!btrfs_test_opt(fs_info, SPACE_CACHE))
return 0;
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
/* Could add new block groups, use _safe just in case */
list_for_each_entry_safe(cache, tmp, &cur_trans->dirty_bgs,
dirty_list) {
if (cache->disk_cache_state == BTRFS_DC_CLEAR)
cache_save_setup(cache, trans, path);
}
btrfs_free_path(path);
return 0;
}
/*
* Transaction commit does final block group cache writeback during a critical
* section where nothing is allowed to change the FS. This is required in
* order for the cache to actually match the block group, but can introduce a
* lot of latency into the commit.
*
* So, btrfs_start_dirty_block_groups is here to kick off block group cache IO.
* There's a chance we'll have to redo some of it if the block group changes
* again during the commit, but it greatly reduces the commit latency by
* getting rid of the easy block groups while we're still allowing others to
* join the commit.
*/
int btrfs_start_dirty_block_groups(struct btrfs_trans_handle *trans)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
struct btrfs_block_group_cache *cache;
struct btrfs_transaction *cur_trans = trans->transaction;
int ret = 0;
int should_put;
struct btrfs_path *path = NULL;
LIST_HEAD(dirty);
struct list_head *io = &cur_trans->io_bgs;
int num_started = 0;
int loops = 0;
spin_lock(&cur_trans->dirty_bgs_lock);
if (list_empty(&cur_trans->dirty_bgs)) {
spin_unlock(&cur_trans->dirty_bgs_lock);
return 0;
}
list_splice_init(&cur_trans->dirty_bgs, &dirty);
spin_unlock(&cur_trans->dirty_bgs_lock);
again:
/* Make sure all the block groups on our dirty list actually exist */
btrfs_create_pending_block_groups(trans);
if (!path) {
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
}
/*
* cache_write_mutex is here only to save us from balance or automatic
* removal of empty block groups deleting this block group while we are
* writing out the cache
*/
mutex_lock(&trans->transaction->cache_write_mutex);
while (!list_empty(&dirty)) {
bool drop_reserve = true;
cache = list_first_entry(&dirty,
struct btrfs_block_group_cache,
dirty_list);
/*
* This can happen if something re-dirties a block group that
* is already under IO. Just wait for it to finish and then do
* it all again
*/
if (!list_empty(&cache->io_list)) {
list_del_init(&cache->io_list);
btrfs_wait_cache_io(trans, cache, path);
btrfs_put_block_group(cache);
}
/*
* btrfs_wait_cache_io uses the cache->dirty_list to decide if
* it should update the cache_state. Don't delete until after
* we wait.
*
* Since we're not running in the commit critical section
* we need the dirty_bgs_lock to protect from update_block_group
*/
spin_lock(&cur_trans->dirty_bgs_lock);
list_del_init(&cache->dirty_list);
spin_unlock(&cur_trans->dirty_bgs_lock);
should_put = 1;
cache_save_setup(cache, trans, path);
if (cache->disk_cache_state == BTRFS_DC_SETUP) {
cache->io_ctl.inode = NULL;
ret = btrfs_write_out_cache(trans, cache, path);
if (ret == 0 && cache->io_ctl.inode) {
num_started++;
should_put = 0;
/*
* The cache_write_mutex is protecting the
* io_list, also refer to the definition of
* btrfs_transaction::io_bgs for more details
*/
list_add_tail(&cache->io_list, io);
} else {
/*
* If we failed to write the cache, the
* generation will be bad and life goes on
*/
ret = 0;
}
}
if (!ret) {
ret = write_one_cache_group(trans, path, cache);
/*
* Our block group might still be attached to the list
* of new block groups in the transaction handle of some
* other task (struct btrfs_trans_handle->new_bgs). This
* means its block group item isn't yet in the extent
* tree. If this happens ignore the error, as we will
* try again later in the critical section of the
* transaction commit.
*/
if (ret == -ENOENT) {
ret = 0;
spin_lock(&cur_trans->dirty_bgs_lock);
if (list_empty(&cache->dirty_list)) {
list_add_tail(&cache->dirty_list,
&cur_trans->dirty_bgs);
btrfs_get_block_group(cache);
drop_reserve = false;
}
spin_unlock(&cur_trans->dirty_bgs_lock);
} else if (ret) {
btrfs_abort_transaction(trans, ret);
}
}
/* If it's not on the io list, we need to put the block group */
if (should_put)
btrfs_put_block_group(cache);
if (drop_reserve)
btrfs_delayed_refs_rsv_release(fs_info, 1);
if (ret)
break;
/*
* Avoid blocking other tasks for too long. It might even save
* us from writing caches for block groups that are going to be
* removed.
*/
mutex_unlock(&trans->transaction->cache_write_mutex);
mutex_lock(&trans->transaction->cache_write_mutex);
}
mutex_unlock(&trans->transaction->cache_write_mutex);
/*
* Go through delayed refs for all the stuff we've just kicked off
* and then loop back (just once)
*/
ret = btrfs_run_delayed_refs(trans, 0);
if (!ret && loops == 0) {
loops++;
spin_lock(&cur_trans->dirty_bgs_lock);
list_splice_init(&cur_trans->dirty_bgs, &dirty);
/*
* dirty_bgs_lock protects us from concurrent block group
* deletes too (not just cache_write_mutex).
*/
if (!list_empty(&dirty)) {
spin_unlock(&cur_trans->dirty_bgs_lock);
goto again;
}
spin_unlock(&cur_trans->dirty_bgs_lock);
} else if (ret < 0) {
btrfs_cleanup_dirty_bgs(cur_trans, fs_info);
}
btrfs_free_path(path);
return ret;
}
int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
struct btrfs_block_group_cache *cache;
struct btrfs_transaction *cur_trans = trans->transaction;
int ret = 0;
int should_put;
struct btrfs_path *path;
struct list_head *io = &cur_trans->io_bgs;
int num_started = 0;
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
/*
* Even though we are in the critical section of the transaction commit,
* we can still have concurrent tasks adding elements to this
* transaction's list of dirty block groups. These tasks correspond to
* endio free space workers started when writeback finishes for a
* space cache, which run inode.c:btrfs_finish_ordered_io(), and can
* allocate new block groups as a result of COWing nodes of the root
* tree when updating the free space inode. The writeback for the space
* caches is triggered by an earlier call to
* btrfs_start_dirty_block_groups() and iterations of the following
* loop.
* Also we want to do the cache_save_setup first and then run the
* delayed refs to make sure we have the best chance at doing this all
* in one shot.
*/
spin_lock(&cur_trans->dirty_bgs_lock);
while (!list_empty(&cur_trans->dirty_bgs)) {
cache = list_first_entry(&cur_trans->dirty_bgs,
struct btrfs_block_group_cache,
dirty_list);
/*
* This can happen if cache_save_setup re-dirties a block group
* that is already under IO. Just wait for it to finish and
* then do it all again
*/
if (!list_empty(&cache->io_list)) {
spin_unlock(&cur_trans->dirty_bgs_lock);
list_del_init(&cache->io_list);
btrfs_wait_cache_io(trans, cache, path);
btrfs_put_block_group(cache);
spin_lock(&cur_trans->dirty_bgs_lock);
}
/*
* Don't remove from the dirty list until after we've waited on
* any pending IO
*/
list_del_init(&cache->dirty_list);
spin_unlock(&cur_trans->dirty_bgs_lock);
should_put = 1;
cache_save_setup(cache, trans, path);
if (!ret)
ret = btrfs_run_delayed_refs(trans,
(unsigned long) -1);
if (!ret && cache->disk_cache_state == BTRFS_DC_SETUP) {
cache->io_ctl.inode = NULL;
ret = btrfs_write_out_cache(trans, cache, path);
if (ret == 0 && cache->io_ctl.inode) {
num_started++;
should_put = 0;
list_add_tail(&cache->io_list, io);
} else {
/*
* If we failed to write the cache, the
* generation will be bad and life goes on
*/
ret = 0;
}
}
if (!ret) {
ret = write_one_cache_group(trans, path, cache);
/*
* One of the free space endio workers might have
* created a new block group while updating a free space
* cache's inode (at inode.c:btrfs_finish_ordered_io())
* and hasn't released its transaction handle yet, in
* which case the new block group is still attached to
* its transaction handle and its creation has not
* finished yet (no block group item in the extent tree
* yet, etc). If this is the case, wait for all free
* space endio workers to finish and retry. This is a
* a very rare case so no need for a more efficient and
* complex approach.
*/
if (ret == -ENOENT) {
wait_event(cur_trans->writer_wait,
atomic_read(&cur_trans->num_writers) == 1);
ret = write_one_cache_group(trans, path, cache);
}
if (ret)
btrfs_abort_transaction(trans, ret);
}
/* If its not on the io list, we need to put the block group */
if (should_put)
btrfs_put_block_group(cache);
btrfs_delayed_refs_rsv_release(fs_info, 1);
spin_lock(&cur_trans->dirty_bgs_lock);
}
spin_unlock(&cur_trans->dirty_bgs_lock);
/*
* Refer to the definition of io_bgs member for details why it's safe
* to use it without any locking
*/
while (!list_empty(io)) {
cache = list_first_entry(io, struct btrfs_block_group_cache,
io_list);
list_del_init(&cache->io_list);
btrfs_wait_cache_io(trans, cache, path);
btrfs_put_block_group(cache);
}
btrfs_free_path(path);
return ret;
}
int btrfs_update_block_group(struct btrfs_trans_handle *trans,
u64 bytenr, u64 num_bytes, int alloc)
{
struct btrfs_fs_info *info = trans->fs_info;
struct btrfs_block_group_cache *cache = NULL;
u64 total = num_bytes;
u64 old_val;
u64 byte_in_group;
int factor;
int ret = 0;
/* Block accounting for super block */
spin_lock(&info->delalloc_root_lock);
old_val = btrfs_super_bytes_used(info->super_copy);
if (alloc)
old_val += num_bytes;
else
old_val -= num_bytes;
btrfs_set_super_bytes_used(info->super_copy, old_val);
spin_unlock(&info->delalloc_root_lock);
while (total) {
cache = btrfs_lookup_block_group(info, bytenr);
if (!cache) {
ret = -ENOENT;
break;
}
factor = btrfs_bg_type_to_factor(cache->flags);
/*
* If this block group has free space cache written out, we
* need to make sure to load it if we are removing space. This
* is because we need the unpinning stage to actually add the
* space back to the block group, otherwise we will leak space.
*/
if (!alloc && cache->cached == BTRFS_CACHE_NO)
btrfs_cache_block_group(cache, 1);
byte_in_group = bytenr - cache->key.objectid;
WARN_ON(byte_in_group > cache->key.offset);
spin_lock(&cache->space_info->lock);
spin_lock(&cache->lock);
if (btrfs_test_opt(info, SPACE_CACHE) &&
cache->disk_cache_state < BTRFS_DC_CLEAR)
cache->disk_cache_state = BTRFS_DC_CLEAR;
old_val = btrfs_block_group_used(&cache->item);
num_bytes = min(total, cache->key.offset - byte_in_group);
if (alloc) {
old_val += num_bytes;
btrfs_set_block_group_used(&cache->item, old_val);
cache->reserved -= num_bytes;
cache->space_info->bytes_reserved -= num_bytes;
cache->space_info->bytes_used += num_bytes;
cache->space_info->disk_used += num_bytes * factor;
spin_unlock(&cache->lock);
spin_unlock(&cache->space_info->lock);
} else {
old_val -= num_bytes;
btrfs_set_block_group_used(&cache->item, old_val);
cache->pinned += num_bytes;
btrfs_space_info_update_bytes_pinned(info,
cache->space_info, num_bytes);
cache->space_info->bytes_used -= num_bytes;
cache->space_info->disk_used -= num_bytes * factor;
spin_unlock(&cache->lock);
spin_unlock(&cache->space_info->lock);
percpu_counter_add_batch(
&cache->space_info->total_bytes_pinned,
num_bytes,
BTRFS_TOTAL_BYTES_PINNED_BATCH);
set_extent_dirty(info->pinned_extents,
bytenr, bytenr + num_bytes - 1,
GFP_NOFS | __GFP_NOFAIL);
}
spin_lock(&trans->transaction->dirty_bgs_lock);
if (list_empty(&cache->dirty_list)) {
list_add_tail(&cache->dirty_list,
&trans->transaction->dirty_bgs);
trans->delayed_ref_updates++;
btrfs_get_block_group(cache);
}
spin_unlock(&trans->transaction->dirty_bgs_lock);
/*
* No longer have used bytes in this block group, queue it for
* deletion. We do this after adding the block group to the
* dirty list to avoid races between cleaner kthread and space
* cache writeout.
*/
if (!alloc && old_val == 0)
btrfs_mark_bg_unused(cache);
btrfs_put_block_group(cache);
total -= num_bytes;
bytenr += num_bytes;
}
/* Modified block groups are accounted for in the delayed_refs_rsv. */
btrfs_update_delayed_refs_rsv(trans);
return ret;
}
/**
* btrfs_add_reserved_bytes - update the block_group and space info counters
* @cache: The cache we are manipulating
* @ram_bytes: The number of bytes of file content, and will be same to
* @num_bytes except for the compress path.
* @num_bytes: The number of bytes in question
* @delalloc: The blocks are allocated for the delalloc write
*
* This is called by the allocator when it reserves space. If this is a
* reservation and the block group has become read only we cannot make the
* reservation and return -EAGAIN, otherwise this function always succeeds.
*/
int btrfs_add_reserved_bytes(struct btrfs_block_group_cache *cache,
u64 ram_bytes, u64 num_bytes, int delalloc)
{
struct btrfs_space_info *space_info = cache->space_info;
int ret = 0;
spin_lock(&space_info->lock);
spin_lock(&cache->lock);
if (cache->ro) {
ret = -EAGAIN;
} else {
cache->reserved += num_bytes;
space_info->bytes_reserved += num_bytes;
trace_btrfs_space_reservation(cache->fs_info, "space_info",
space_info->flags, num_bytes, 1);
btrfs_space_info_update_bytes_may_use(cache->fs_info,
space_info, -ram_bytes);
if (delalloc)
cache->delalloc_bytes += num_bytes;
}
spin_unlock(&cache->lock);
spin_unlock(&space_info->lock);
return ret;
}
/**
* btrfs_free_reserved_bytes - update the block_group and space info counters
* @cache: The cache we are manipulating
* @num_bytes: The number of bytes in question
* @delalloc: The blocks are allocated for the delalloc write
*
* This is called by somebody who is freeing space that was never actually used
* on disk. For example if you reserve some space for a new leaf in transaction
* A and before transaction A commits you free that leaf, you call this with
* reserve set to 0 in order to clear the reservation.
*/
void btrfs_free_reserved_bytes(struct btrfs_block_group_cache *cache,
u64 num_bytes, int delalloc)
{
struct btrfs_space_info *space_info = cache->space_info;
spin_lock(&space_info->lock);
spin_lock(&cache->lock);
if (cache->ro)
space_info->bytes_readonly += num_bytes;
cache->reserved -= num_bytes;
space_info->bytes_reserved -= num_bytes;
space_info->max_extent_size = 0;
if (delalloc)
cache->delalloc_bytes -= num_bytes;
spin_unlock(&cache->lock);
spin_unlock(&space_info->lock);
}
static void force_metadata_allocation(struct btrfs_fs_info *info)
{
struct list_head *head = &info->space_info;
struct btrfs_space_info *found;
rcu_read_lock();
list_for_each_entry_rcu(found, head, list) {
if (found->flags & BTRFS_BLOCK_GROUP_METADATA)
found->force_alloc = CHUNK_ALLOC_FORCE;
}
rcu_read_unlock();
}
static int should_alloc_chunk(struct btrfs_fs_info *fs_info,
struct btrfs_space_info *sinfo, int force)
{
u64 bytes_used = btrfs_space_info_used(sinfo, false);
u64 thresh;
if (force == CHUNK_ALLOC_FORCE)
return 1;
/*
* in limited mode, we want to have some free space up to
* about 1% of the FS size.
*/
if (force == CHUNK_ALLOC_LIMITED) {
thresh = btrfs_super_total_bytes(fs_info->super_copy);
thresh = max_t(u64, SZ_64M, div_factor_fine(thresh, 1));
if (sinfo->total_bytes - bytes_used < thresh)
return 1;
}
if (bytes_used + SZ_2M < div_factor(sinfo->total_bytes, 8))
return 0;
return 1;
}
int btrfs_force_chunk_alloc(struct btrfs_trans_handle *trans, u64 type)
{
u64 alloc_flags = btrfs_get_alloc_profile(trans->fs_info, type);
return btrfs_chunk_alloc(trans, alloc_flags, CHUNK_ALLOC_FORCE);
}
/*
* If force is CHUNK_ALLOC_FORCE:
* - return 1 if it successfully allocates a chunk,
* - return errors including -ENOSPC otherwise.
* If force is NOT CHUNK_ALLOC_FORCE:
* - return 0 if it doesn't need to allocate a new chunk,
* - return 1 if it successfully allocates a chunk,
* - return errors including -ENOSPC otherwise.
*/
int btrfs_chunk_alloc(struct btrfs_trans_handle *trans, u64 flags,
enum btrfs_chunk_alloc_enum force)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
struct btrfs_space_info *space_info;
bool wait_for_alloc = false;
bool should_alloc = false;
int ret = 0;
/* Don't re-enter if we're already allocating a chunk */
if (trans->allocating_chunk)
return -ENOSPC;
space_info = btrfs_find_space_info(fs_info, flags);
ASSERT(space_info);
do {
spin_lock(&space_info->lock);
if (force < space_info->force_alloc)
force = space_info->force_alloc;
should_alloc = should_alloc_chunk(fs_info, space_info, force);
if (space_info->full) {
/* No more free physical space */
if (should_alloc)
ret = -ENOSPC;
else
ret = 0;
spin_unlock(&space_info->lock);
return ret;
} else if (!should_alloc) {
spin_unlock(&space_info->lock);
return 0;
} else if (space_info->chunk_alloc) {
/*
* Someone is already allocating, so we need to block
* until this someone is finished and then loop to
* recheck if we should continue with our allocation
* attempt.
*/
wait_for_alloc = true;
spin_unlock(&space_info->lock);
mutex_lock(&fs_info->chunk_mutex);
mutex_unlock(&fs_info->chunk_mutex);
} else {
/* Proceed with allocation */
space_info->chunk_alloc = 1;
wait_for_alloc = false;
spin_unlock(&space_info->lock);
}
cond_resched();
} while (wait_for_alloc);
mutex_lock(&fs_info->chunk_mutex);
trans->allocating_chunk = true;
/*
* If we have mixed data/metadata chunks we want to make sure we keep
* allocating mixed chunks instead of individual chunks.
*/
if (btrfs_mixed_space_info(space_info))
flags |= (BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA);
/*
* if we're doing a data chunk, go ahead and make sure that
* we keep a reasonable number of metadata chunks allocated in the
* FS as well.
*/
if (flags & BTRFS_BLOCK_GROUP_DATA && fs_info->metadata_ratio) {
fs_info->data_chunk_allocations++;
if (!(fs_info->data_chunk_allocations %
fs_info->metadata_ratio))
force_metadata_allocation(fs_info);
}
/*
* Check if we have enough space in SYSTEM chunk because we may need
* to update devices.
*/
check_system_chunk(trans, flags);
ret = btrfs_alloc_chunk(trans, flags);
trans->allocating_chunk = false;
spin_lock(&space_info->lock);
if (ret < 0) {
if (ret == -ENOSPC)
space_info->full = 1;
else
goto out;
} else {
ret = 1;
space_info->max_extent_size = 0;
}
space_info->force_alloc = CHUNK_ALLOC_NO_FORCE;
out:
space_info->chunk_alloc = 0;
spin_unlock(&space_info->lock);
mutex_unlock(&fs_info->chunk_mutex);
/*
* When we allocate a new chunk we reserve space in the chunk block
* reserve to make sure we can COW nodes/leafs in the chunk tree or
* add new nodes/leafs to it if we end up needing to do it when
* inserting the chunk item and updating device items as part of the
* second phase of chunk allocation, performed by
* btrfs_finish_chunk_alloc(). So make sure we don't accumulate a
* large number of new block groups to create in our transaction
* handle's new_bgs list to avoid exhausting the chunk block reserve
* in extreme cases - like having a single transaction create many new
* block groups when starting to write out the free space caches of all
* the block groups that were made dirty during the lifetime of the
* transaction.
*/
if (trans->chunk_bytes_reserved >= (u64)SZ_2M)
btrfs_create_pending_block_groups(trans);
return ret;
}
static u64 get_profile_num_devs(struct btrfs_fs_info *fs_info, u64 type)
{
u64 num_dev;
num_dev = btrfs_raid_array[btrfs_bg_flags_to_raid_index(type)].devs_max;
if (!num_dev)
num_dev = fs_info->fs_devices->rw_devices;
return num_dev;
}
/*
* If @is_allocation is true, reserve space in the system space info necessary
* for allocating a chunk, otherwise if it's false, reserve space necessary for
* removing a chunk.
*/
void check_system_chunk(struct btrfs_trans_handle *trans, u64 type)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
struct btrfs_space_info *info;
u64 left;
u64 thresh;
int ret = 0;
u64 num_devs;
/*
* Needed because we can end up allocating a system chunk and for an
* atomic and race free space reservation in the chunk block reserve.
*/
lockdep_assert_held(&fs_info->chunk_mutex);
info = btrfs_find_space_info(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
spin_lock(&info->lock);
left = info->total_bytes - btrfs_space_info_used(info, true);
spin_unlock(&info->lock);
num_devs = get_profile_num_devs(fs_info, type);
/* num_devs device items to update and 1 chunk item to add or remove */
thresh = btrfs_calc_metadata_size(fs_info, num_devs) +
btrfs_calc_insert_metadata_size(fs_info, 1);
if (left < thresh && btrfs_test_opt(fs_info, ENOSPC_DEBUG)) {
btrfs_info(fs_info, "left=%llu, need=%llu, flags=%llu",
left, thresh, type);
btrfs_dump_space_info(fs_info, info, 0, 0);
}
if (left < thresh) {
u64 flags = btrfs_system_alloc_profile(fs_info);
/*
* Ignore failure to create system chunk. We might end up not
* needing it, as we might not need to COW all nodes/leafs from
* the paths we visit in the chunk tree (they were already COWed
* or created in the current transaction for example).
*/
ret = btrfs_alloc_chunk(trans, flags);
}
if (!ret) {
ret = btrfs_block_rsv_add(fs_info->chunk_root,
&fs_info->chunk_block_rsv,
thresh, BTRFS_RESERVE_NO_FLUSH);
if (!ret)
trans->chunk_bytes_reserved += thresh;
}
}
void btrfs_put_block_group_cache(struct btrfs_fs_info *info)
{
struct btrfs_block_group_cache *block_group;
u64 last = 0;
while (1) {
struct inode *inode;
block_group = btrfs_lookup_first_block_group(info, last);
while (block_group) {
btrfs_wait_block_group_cache_done(block_group);
spin_lock(&block_group->lock);
if (block_group->iref)
break;
spin_unlock(&block_group->lock);
block_group = btrfs_next_block_group(block_group);
}
if (!block_group) {
if (last == 0)
break;
last = 0;
continue;
}
inode = block_group->inode;
block_group->iref = 0;
block_group->inode = NULL;
spin_unlock(&block_group->lock);
ASSERT(block_group->io_ctl.inode == NULL);
iput(inode);
last = block_group->key.objectid + block_group->key.offset;
btrfs_put_block_group(block_group);
}
}
/*
* Must be called only after stopping all workers, since we could have block
* group caching kthreads running, and therefore they could race with us if we
* freed the block groups before stopping them.
*/
int btrfs_free_block_groups(struct btrfs_fs_info *info)
{
struct btrfs_block_group_cache *block_group;
struct btrfs_space_info *space_info;
struct btrfs_caching_control *caching_ctl;
struct rb_node *n;
down_write(&info->commit_root_sem);
while (!list_empty(&info->caching_block_groups)) {
caching_ctl = list_entry(info->caching_block_groups.next,
struct btrfs_caching_control, list);
list_del(&caching_ctl->list);
btrfs_put_caching_control(caching_ctl);
}
up_write(&info->commit_root_sem);
spin_lock(&info->unused_bgs_lock);
while (!list_empty(&info->unused_bgs)) {
block_group = list_first_entry(&info->unused_bgs,
struct btrfs_block_group_cache,
bg_list);
list_del_init(&block_group->bg_list);
btrfs_put_block_group(block_group);
}
spin_unlock(&info->unused_bgs_lock);
spin_lock(&info->block_group_cache_lock);
while ((n = rb_last(&info->block_group_cache_tree)) != NULL) {
block_group = rb_entry(n, struct btrfs_block_group_cache,
cache_node);
rb_erase(&block_group->cache_node,
&info->block_group_cache_tree);
RB_CLEAR_NODE(&block_group->cache_node);
spin_unlock(&info->block_group_cache_lock);
down_write(&block_group->space_info->groups_sem);
list_del(&block_group->list);
up_write(&block_group->space_info->groups_sem);
/*
* We haven't cached this block group, which means we could
* possibly have excluded extents on this block group.
*/
if (block_group->cached == BTRFS_CACHE_NO ||
block_group->cached == BTRFS_CACHE_ERROR)
btrfs_free_excluded_extents(block_group);
btrfs_remove_free_space_cache(block_group);
ASSERT(block_group->cached != BTRFS_CACHE_STARTED);
ASSERT(list_empty(&block_group->dirty_list));
ASSERT(list_empty(&block_group->io_list));
ASSERT(list_empty(&block_group->bg_list));
ASSERT(atomic_read(&block_group->count) == 1);
btrfs_put_block_group(block_group);
spin_lock(&info->block_group_cache_lock);
}
spin_unlock(&info->block_group_cache_lock);
/*
* Now that all the block groups are freed, go through and free all the
* space_info structs. This is only called during the final stages of
* unmount, and so we know nobody is using them. We call
* synchronize_rcu() once before we start, just to be on the safe side.
*/
synchronize_rcu();
btrfs_release_global_block_rsv(info);
while (!list_empty(&info->space_info)) {
space_info = list_entry(info->space_info.next,
struct btrfs_space_info,
list);
/*
* Do not hide this behind enospc_debug, this is actually
* important and indicates a real bug if this happens.
*/
if (WARN_ON(space_info->bytes_pinned > 0 ||
space_info->bytes_reserved > 0 ||
space_info->bytes_may_use > 0))
btrfs_dump_space_info(info, space_info, 0, 0);
list_del(&space_info->list);
btrfs_sysfs_remove_space_info(space_info);
}
return 0;
}
