From: Dai Ngo Date: Wed, 20 May 2026 00:32:59 +0000 (-0700) Subject: xfs: fix overlapping extents returned for pNFS LAYOUTGET X-Git-Url: http://git.ipfire.org/gitweb/index.cgi?a=commitdiff_plain;h=36ca6f11424a5b6d92b88df37c40bf2fe825d5a0;p=thirdparty%2Fkernel%2Flinux.git xfs: fix overlapping extents returned for pNFS LAYOUTGET xfs_fs_map_blocks() currently passes XFS_BMAPI_ENTIRE to xfs_bmapi_read(), which causes the bmap code to expand the mapping to cover the entire extent rather than the requested range. A single LAYOUTGET request from the client can cause the server to issue multiple calls to xfs_fs_map_blocks() for different offsets within the same extent. Because the use of XFS_BMAPI_ENTIRE flag, these calls can produce overlapping mappings. As a result, the LAYOUTGET reply sent to the NFS client may contain overlapping extents. This creates ambiguity in extent selection for a given file range, which can lead to incorrect device selection, inconsistent handling of datastate, and ultimately data corruption or protocol violations on the client side. Problem discovered with xfstest generic/075 test using NFSv4.2 mount with SCSI layout. Fix this by replacing the XFS_BMAPI_ENTIRE flag with '0' so that xfs_bmapi_read() returns only the mapping for the requested range. Fixes: cc6c40e09d7b1 ("NFSD/blocklayout: Support multiple extents per LAYOUTGET"). Signed-off-by: Dai Ngo Reviewed-by: Carlos Maiolino Reviewed-by: Christoph Hellwig Signed-off-by: Carlos Maiolino --- diff --git a/fs/xfs/xfs_pnfs.c b/fs/xfs/xfs_pnfs.c index b792e066b403..d92993367ab6 100644 --- a/fs/xfs/xfs_pnfs.c +++ b/fs/xfs/xfs_pnfs.c @@ -118,7 +118,6 @@ xfs_fs_map_blocks( struct xfs_bmbt_irec imap; xfs_fileoff_t offset_fsb, end_fsb; loff_t limit; - int bmapi_flags = XFS_BMAPI_ENTIRE; int nimaps = 1; uint lock_flags; int error = 0; @@ -172,8 +171,9 @@ xfs_fs_map_blocks( offset_fsb = XFS_B_TO_FSBT(mp, offset); lock_flags = xfs_ilock_data_map_shared(ip); + /* request mappings for the specified range only */ error = xfs_bmapi_read(ip, offset_fsb, end_fsb - offset_fsb, - &imap, &nimaps, bmapi_flags); + &imap, &nimaps, 0); if (error) { xfs_iunlock(ip, lock_flags); goto out_unlock;