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btrfs: qgroup: Introduce extent changeset for qgroup reserve functions

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Introduce a new parameter, struct extent_changeset for
btrfs_qgroup_reserved_data() and its callers.

Such extent_changeset was used in btrfs_qgroup_reserve_data() to record
which range it reserved in current reserve, so it can free it in error
paths.

The reason we need to export it to callers is, at buffered write error
path, without knowing what exactly which range we reserved in current
allocation, we can free space which is not reserved by us.

This will lead to qgroup reserved space underflow.

Reviewed-by: Chandan Rajendra <chandan@linux.vnet.ibm.com>
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Qu Wenruo
2017-02-27 15:10:38 +08:00
committed by David Sterba
parent a12b877b55
commit 364ecf3651
10 changed files with 119 additions and 41 deletions
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23
fs/btrfs/extent-tree.c
View File

@@ -3402,6 +3402,7 @@ static int cache_save_setup(struct btrfs_block_group_cache *block_group,
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;
@@ -3521,7 +3522,7 @@ again:
num_pages *= 16;
num_pages *= PAGE_SIZE;
ret = btrfs_check_data_free_space(inode, 0, num_pages);
ret = btrfs_check_data_free_space(inode, &data_reserved, 0, num_pages);
if (ret)
goto out_put;
@@ -3552,6 +3553,7 @@ out:
block_group->disk_cache_state = dcs;
spin_unlock(&block_group->lock);
extent_changeset_free(data_reserved);
return ret;
}
@@ -4326,12 +4328,8 @@ commit_trans:
return ret;
}
/*
* New check_data_free_space() with ability for precious data reservation
* Will replace old btrfs_check_data_free_space(), but for patch split,
* add a new function first and then replace it.
*/
int btrfs_check_data_free_space(struct inode *inode, u64 start, u64 len)
int btrfs_check_data_free_space(struct inode *inode,
struct extent_changeset **reserved, u64 start, u64 len)
{
struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
int ret;
@@ -4346,9 +4344,11 @@ int btrfs_check_data_free_space(struct inode *inode, u64 start, u64 len)
return ret;
/* Use new btrfs_qgroup_reserve_data to reserve precious data space. */
ret = btrfs_qgroup_reserve_data(inode, start, len);
ret = btrfs_qgroup_reserve_data(inode, reserved, start, len);
if (ret < 0)
btrfs_free_reserved_data_space_noquota(inode, start, len);
else
ret = 0;
return ret;
}
@@ -6175,6 +6175,8 @@ void btrfs_delalloc_release_metadata(struct btrfs_inode *inode, u64 num_bytes)
* @inode: inode we're writing to
* @start: start range we are writing to
* @len: how long the range we are writing to
* @reserved: mandatory parameter, record actually reserved qgroup ranges of
* current reservation.
*
* This will do the following things
*
@@ -6192,11 +6194,12 @@ void btrfs_delalloc_release_metadata(struct btrfs_inode *inode, u64 num_bytes)
* Return 0 for success
* Return <0 for error(-ENOSPC or -EQUOT)
*/
int btrfs_delalloc_reserve_space(struct inode *inode, u64 start, u64 len)
int btrfs_delalloc_reserve_space(struct inode *inode,
struct extent_changeset **reserved, u64 start, u64 len)
{
int ret;
ret = btrfs_check_data_free_space(inode, start, len);
ret = btrfs_check_data_free_space(inode, reserved, start, len);
if (ret < 0)
return ret;
ret = btrfs_delalloc_reserve_metadata(BTRFS_I(inode), len);