diff options
Diffstat (limited to 'fs/xfs/libxfs/xfs_refcount.h')
| -rw-r--r-- | fs/xfs/libxfs/xfs_refcount.h | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/fs/xfs/libxfs/xfs_refcount.h b/fs/xfs/libxfs/xfs_refcount.h index 9eb01edbd89d..37145637d7d8 100644 --- a/fs/xfs/libxfs/xfs_refcount.h +++ b/fs/xfs/libxfs/xfs_refcount.h @@ -67,6 +67,14 @@ extern int xfs_refcount_recover_cow_leftovers(struct xfs_mount *mp, * log (plus any key updates) so we'll conservatively assume 32 bytes * per record. We must also leave space for btree splits on both ends * of the range and space for the CUD and a new CUI. + * + * Each EFI that we attach to the transaction is assumed to consume ~32 bytes. + * This is a low estimate for an EFI tracking a single extent (16 bytes for the + * EFI header, 16 for the extent, and 12 for the xlog op header), but the + * estimate is acceptable if there's more than one extent being freed. + * In the worst case of freeing every other block during a refcount decrease + * operation, we amortize the space used for one EFI log item across 16 + * extents. */ #define XFS_REFCOUNT_ITEM_OVERHEAD 32 |