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btrfs: divide btrfs_update_reserved_bytes() into two functions
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This patch divides btrfs_update_reserved_bytes() into
btrfs_add_reserved_bytes() and btrfs_free_reserved_bytes(), and
next patch will extend btrfs_add_reserved_bytes（）to fix some
false ENOSPC error, please see later patch for detailed info.

Signed-off-by: Wang Xiaoguang <wangxg.fnst@cn.fujitsu.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
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Wang Xiaoguang authored and Chris Mason committed Aug 25, 2016
1 parent dcb40c1 commit 4824f1f
Showing 1 changed file with 57 additions and 40 deletions.
97 changes: 57 additions & 40 deletions fs/btrfs/extent-tree.c
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Original file line number Diff line number Diff line change
Expand Up @@ -104,9 +104,10 @@ static int find_next_key(struct btrfs_path *path, int level,
struct btrfs_key *key);
static void dump_space_info(struct btrfs_space_info *info, u64 bytes,
int dump_block_groups);
static int btrfs_update_reserved_bytes(struct btrfs_block_group_cache *cache,
u64 num_bytes, int reserve,
int delalloc);
static int btrfs_add_reserved_bytes(struct btrfs_block_group_cache *cache,
u64 num_bytes, int reserve, int delalloc);
static int btrfs_free_reserved_bytes(struct btrfs_block_group_cache *cache,
u64 num_bytes, int delalloc);
static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv,
u64 num_bytes);
int btrfs_pin_extent(struct btrfs_root *root,
Expand Down Expand Up @@ -6497,19 +6498,14 @@ void btrfs_wait_block_group_reservations(struct btrfs_block_group_cache *bg)
}

/**
* btrfs_update_reserved_bytes - update the block_group and space info counters
* btrfs_add_reserved_bytes - update the block_group and space info counters
* @cache: The cache we are manipulating
* @num_bytes: The number of bytes in question
* @reserve: One of the reservation enums
* @delalloc: The blocks are allocated for the delalloc write
*
* This is called by the allocator when it reserves space, or 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.
*
* Metadata reservations should be called with RESERVE_ALLOC so we do the proper
* This is called by the allocator when it reserves space. Metadata
* reservations should be called with RESERVE_ALLOC so we do the proper
* ENOSPC accounting. For data we handle the reservation through clearing the
* delalloc bits in the io_tree. We have to do this since we could end up
* allocating less disk space for the amount of data we have reserved in the
Expand All @@ -6519,44 +6515,65 @@ void btrfs_wait_block_group_reservations(struct btrfs_block_group_cache *bg)
* make the reservation and return -EAGAIN, otherwise this function always
* succeeds.
*/
static int btrfs_update_reserved_bytes(struct btrfs_block_group_cache *cache,
u64 num_bytes, int reserve, int delalloc)
static int btrfs_add_reserved_bytes(struct btrfs_block_group_cache *cache,
u64 num_bytes, int reserve, int delalloc)
{
struct btrfs_space_info *space_info = cache->space_info;
int ret = 0;

spin_lock(&space_info->lock);
spin_lock(&cache->lock);
if (reserve != RESERVE_FREE) {
if (cache->ro) {
ret = -EAGAIN;
} else {
cache->reserved += num_bytes;
space_info->bytes_reserved += num_bytes;
if (reserve == RESERVE_ALLOC) {
trace_btrfs_space_reservation(cache->fs_info,
"space_info", space_info->flags,
num_bytes, 0);
space_info->bytes_may_use -= num_bytes;
}

if (delalloc)
cache->delalloc_bytes += num_bytes;
}
if (cache->ro) {
ret = -EAGAIN;
} else {
if (cache->ro)
space_info->bytes_readonly += num_bytes;
cache->reserved -= num_bytes;
space_info->bytes_reserved -= num_bytes;
cache->reserved += num_bytes;
space_info->bytes_reserved += num_bytes;
if (reserve == RESERVE_ALLOC) {
trace_btrfs_space_reservation(cache->fs_info,
"space_info", space_info->flags,
num_bytes, 0);
space_info->bytes_may_use -= num_bytes;
}

if (delalloc)
cache->delalloc_bytes -= num_bytes;
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.
*/

static int btrfs_free_reserved_bytes(struct btrfs_block_group_cache *cache,
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)
space_info->bytes_readonly += num_bytes;
cache->reserved -= num_bytes;
space_info->bytes_reserved -= num_bytes;

if (delalloc)
cache->delalloc_bytes -= num_bytes;
spin_unlock(&cache->lock);
spin_unlock(&space_info->lock);
return ret;
}
void btrfs_prepare_extent_commit(struct btrfs_trans_handle *trans,
struct btrfs_root *root)
{
Expand Down Expand Up @@ -7191,7 +7208,7 @@ void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
WARN_ON(test_bit(EXTENT_BUFFER_DIRTY, &buf->bflags));

btrfs_add_free_space(cache, buf->start, buf->len);
btrfs_update_reserved_bytes(cache, buf->len, RESERVE_FREE, 0);
btrfs_free_reserved_bytes(cache, buf->len, 0);
btrfs_put_block_group(cache);
trace_btrfs_reserved_extent_free(root, buf->start, buf->len);
pin = 0;
Expand Down Expand Up @@ -7763,8 +7780,8 @@ static noinline int find_free_extent(struct btrfs_root *orig_root,
search_start - offset);
BUG_ON(offset > search_start);

ret = btrfs_update_reserved_bytes(block_group, num_bytes,
alloc_type, delalloc);
ret = btrfs_add_reserved_bytes(block_group, num_bytes,
alloc_type, delalloc);
if (ret == -EAGAIN) {
btrfs_add_free_space(block_group, offset, num_bytes);
goto loop;
Expand Down Expand Up @@ -7995,7 +8012,7 @@ static int __btrfs_free_reserved_extent(struct btrfs_root *root,
if (btrfs_test_opt(root->fs_info, DISCARD))
ret = btrfs_discard_extent(root, start, len, NULL);
btrfs_add_free_space(cache, start, len);
btrfs_update_reserved_bytes(cache, len, RESERVE_FREE, delalloc);
btrfs_free_reserved_bytes(cache, len, delalloc);
trace_btrfs_reserved_extent_free(root, start, len);
}

Expand Down Expand Up @@ -8223,8 +8240,8 @@ int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans,
if (!block_group)
return -EINVAL;

ret = btrfs_update_reserved_bytes(block_group, ins->offset,
RESERVE_ALLOC_NO_ACCOUNT, 0);
ret = btrfs_add_reserved_bytes(block_group, ins->offset,
RESERVE_ALLOC_NO_ACCOUNT, 0);
BUG_ON(ret); /* logic error */
ret = alloc_reserved_file_extent(trans, root, 0, root_objectid,
0, owner, offset, ins, 1);
Expand Down

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