xfs: fix xfs_bunmapi to allow unmapping of partial rt extents

When XFS_BMAPI_REMAP is passed to bunmapi, that means that we want to
remove part of a block mapping without touching the allocator.  For
realtime files with rtextsize > 1, that also means that we should skip
all the code that changes a partial remove request into an unwritten
extent conversion.  IOWs, bunmapi in this mode should handle removing
the mapping from the rt file and nothing else.

Note that XFS_BMAPI_REMAP callers are required to decrement the
reference count and/or free the space manually.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
This commit is contained in:
Darrick J. Wong 2024-02-22 12:44:22 -08:00
parent c75f1a2c15
commit 2b6a5ec268

View File

@ -5459,7 +5459,7 @@ __xfs_bunmapi(
if (del.br_startoff + del.br_blockcount > end + 1)
del.br_blockcount = end + 1 - del.br_startoff;
if (!isrt)
if (!isrt || (flags & XFS_BMAPI_REMAP))
goto delete;
mod = xfs_rtb_to_rtxoff(mp,
@ -5477,7 +5477,7 @@ __xfs_bunmapi(
* This piece is unwritten, or we're not
* using unwritten extents. Skip over it.
*/
ASSERT(end >= mod);
ASSERT((flags & XFS_BMAPI_REMAP) || end >= mod);
end -= mod > del.br_blockcount ?
del.br_blockcount : mod;
if (end < got.br_startoff &&