@@ -2143,6 +2143,7 @@ static int insert_reserved_file_extent(struct btrfs_trans_handle *trans,
struct btrfs_path *path;
struct extent_buffer *leaf;
struct btrfs_key ins;
+ u64 qg_released;
int extent_inserted = 0;
int ret;
@@ -2198,13 +2199,17 @@ static int insert_reserved_file_extent(struct btrfs_trans_handle *trans,
ins.objectid = disk_bytenr;
ins.offset = disk_num_bytes;
ins.type = BTRFS_EXTENT_ITEM_KEY;
- ret = btrfs_alloc_reserved_file_extent(trans, root->root_key.objectid,
- btrfs_ino(BTRFS_I(inode)), file_pos, ram_bytes, &ins);
+
/*
* Release the reserved range from inode dirty range map, as it is
* already moved into delayed_ref_head
*/
- btrfs_qgroup_release_data(inode, file_pos, ram_bytes);
+ ret = btrfs_qgroup_release_data(inode, file_pos, ram_bytes);
+ if (ret < 0)
+ goto out;
+ qg_released = ret;
+ ret = btrfs_alloc_reserved_file_extent(trans, root->root_key.objectid,
+ btrfs_ino(BTRFS_I(inode)), file_pos, qg_released, &ins);
out:
btrfs_free_path(path);
[BUG] Under the following case, we can underflow qgroup reserved space. Task A | Task B --------------------------------------------------------------- Quota disabled | Buffered write | |- btrfs_check_data_free_space() | | *NO* qgroup space is reserved | | since quota is *DISABLED* | |- All pages are copied to page | cache | | Enable quota | Quota scan finished | | Sync_fs | |- run_delalloc_range | |- Write pages | |- btrfs_finish_ordered_io | |- insert_reserved_file_extent | |- btrfs_qgroup_release_data() | Since no qgroup space is reserved in Task A, we underflow qgroup reserved space This can be detected by fstest btrfs/104. [CAUSE] In insert_reserved_file_extent() we info qgroup to release the @ram_bytes size of qgroup reserved_space under all case. And btrfs_qgroup_release_data() will check if qgroup is enabled. However in above case, the buffered write happens before quota is enabled, so we don't havee reserved space for that range. [FIX] In insert_reserved_file_extent(), we info qgroup to release the acctual byte number it released. In above case, since we don't have reserved space, we info qgroup to release 0 byte, so the problem can be fixed. And thanks to the @reserved parameter introduced by qgroup rework, and previous patch to return release bytes, the fix can be as small as less than 10 lines. Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com> --- fs/btrfs/inode.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-)