[PATCH 10/10] xfs: punch delalloc extents from the COW fork for COW writes

Christoph Hellwig
2024-09-24T07:41:49Z

When ->iomap_end is called on a short write to the COW fork it needs to
punch stale delalloc data from the COW fork and not the data fork.

Ensure that IOMAP_F_NEW is set for new COW fork allocations in
xfs_buffered_write_iomap_begin, and then use the IOMAP_F_SHARED flag
in xfs_buffered_write_delalloc_punch to decide which fork to punch.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
---
fs/xfs/xfs_iomap.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
index cc768f0139d365..8a4e5f14ec0c77 100644
--- a/fs/xfs/xfs_iomap.c
+++ b/fs/xfs/xfs_iomap.c
@@ -1195,7 +1195,7 @@ xfs_buffered_write_iomap_begin(
xfs_trim_extent(&cmap, offset_fsb, imap.br_startoff - offset_fsb);
}

- iomap_flags = IOMAP_F_SHARED;
+ iomap_flags |= IOMAP_F_SHARED;
seq = xfs_iomap_inode_sequence(ip, iomap_flags);
xfs_iunlock(ip, lockmode);
return xfs_bmbt_to_iomap(ip, iomap, &cmap, flags, iomap_flags, seq);
@@ -1212,8 +1212,10 @@ xfs_buffered_write_delalloc_punch(
loff_t length,
struct iomap *iomap)
{
- xfs_bmap_punch_delalloc_range(XFS_I(inode), XFS_DATA_FORK, offset,
- offset + length);
+ xfs_bmap_punch_delalloc_range(XFS_I(inode),
+ (iomap->flags & IOMAP_F_SHARED) ?
+ XFS_COW_FORK : XFS_DATA_FORK,
+ offset, offset + length);
}

static int
--
2.45.2