xfs: support lowmode allocations in xfs_bmap_exact_minlen_extent_alloc

Source kernel commit: 6aac77059881e4419df499392c995bf02fb9630b

Currently the debug-only xfs_bmap_exact_minlen_extent_alloc allocation
variant fails to drop into the lowmode last resort allocator, and
thus can sometimes fail allocations for which the caller has a
transaction block reservation.

Fix this by using xfs_bmap_btalloc_low_space to do the actual allocation.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Carlos Maiolino <cem@kernel.org>

diff --git a/libxfs/xfs_bmap.c b/libxfs/xfs_bmap.c
index 02f26854c53cfe4103be8f959c2b9905eca859b3..aec378ff4a9193b3738e95e29388b4d2db617ed2 100644 (file)
--- a/libxfs/xfs_bmap.c
+++ b/libxfs/xfs_bmap.c
@@ -3495,7 +3495,13 @@ xfs_bmap_exact_minlen_extent_alloc(
         */
        ap->blkno = XFS_AGB_TO_FSB(ap->ip->i_mount, 0, 0);
 
-       return xfs_alloc_vextent_first_ag(args, ap->blkno);
+       /*
+        * Call xfs_bmap_btalloc_low_space here as it first does a "normal" AG
+        * iteration and then drops args->total to args->minlen, which might be
+        * required to find an allocation for the transaction reservation when
+        * the file system is very full.
+        */
+       return xfs_bmap_btalloc_low_space(ap, args);
 }
 
 /*