[PATCH 32/35] btrfs: only free reserved extent if we didn't insert it

Josef Bacik
2018-08-30T21:46:42Z

When we insert the file extent once the ordered extent completes we free
the reserved extent reservation as it'll have been migrated to the
bytes_used counter. However if we error out after this step we'll still
clear the reserved extent reservation, resulting in a negative
accounting of the reserved bytes for the block group and space info.
Fix this by only doing the free if we didn't successfully insert a file
extent for this extent.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
---
fs/btrfs/inode.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 10455d0aa71c..3391f6a9fc77 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -2992,6 +2992,7 @@ static int btrfs_finish_ordered_io(struct btrfs_ordered_extent *ordered_extent)
bool truncated = false;
bool range_locked = false;
bool clear_new_delalloc_bytes = false;
+ bool clear_reserved_extent = true;

if (!test_bit(BTRFS_ORDERED_NOCOW, &ordered_extent->flags) &&
!test_bit(BTRFS_ORDERED_PREALLOC, &ordered_extent->flags) &&
@@ -3095,10 +3096,12 @@ static int btrfs_finish_ordered_io(struct btrfs_ordered_extent *ordered_extent)
logical_len, logical_len,
compress_type, 0, 0,
BTRFS_FILE_EXTENT_REG);
- if (!ret)
+ if (!ret) {
+ clear_reserved_extent = false;
btrfs_release_delalloc_bytes(fs_info,
ordered_extent->start,
ordered_extent->disk_len);
+ }
}
unpin_extent_cache(&BTRFS_I(inode)->extent_tree,
ordered_extent->file_offset, ordered_extent->len,
@@ -3159,8 +3162,13 @@ static int btrfs_finish_ordered_io(struct btrfs_ordered_extent *ordered_extent)
* wrong we need to return the space for this ordered extent
* back to the allocator. We only free the extent in the
* truncated case if we didn't write out the extent at all.
+ *
+ * If we made it past insert_reserved_file_extent before we
+ * errored out then we don't need to do this as the accounting
+ * has already been done.
*/
if ((ret || !logical_len) &&
+ clear_reserved_extent &&
!test_bit(BTRFS_ORDERED_NOCOW, &ordered_extent->flags) &&
!test_bit(BTRFS_ORDERED_PREALLOC, &ordered_extent->flags))
btrfs_free_reserved_extent(fs_info,
--
2.14.3