xfs: don't rely on ->total in xfs_alloc_space_available Source kernel commit: 12ef830198b0d71668eb9b59f9ba69d32951a48a ->total is a bit of an odd parameter passed down to the low-level allocator all the way from the high-level callers. It's supposed to contain the maximum number of blocks to be allocated for the whole transaction [1]. But in xfs_iomap_write_allocate we only convert existing delayed allocations and thus only have a minimal block reservation for the current transaction, so xfs_alloc_space_available can't use it for the allocation decisions. Use the maximum of args->total and the calculated block requirement to make a decision. We probably should get rid of args->total eventually and instead apply ->minleft more broadly, but that will require some extensive changes all over. [1] which creates lots of confusion as most callers don't decrement it once doing a first allocation. But that's for a separate series. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Brian Foster <bfoster@redhat.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Eric Sandeen <sandeen@sandeen.net>

diff --git a/libxfs/xfs_alloc.c b/libxfs/xfs_alloc.c
index cbcd9dc..c879757 100644
--- a/libxfs/xfs_alloc.c
+++ b/libxfs/xfs_alloc.c

@@ -1991,7 +1991,7 @@
 	int			flags)
 {
 	struct xfs_perag	*pag = args->pag;
-	xfs_extlen_t		longest;
+	xfs_extlen_t		alloc_len, longest;
 	xfs_extlen_t		reservation; /* blocks that are still reserved */
 	int			available;
 
@@ -2001,15 +2001,16 @@
 	reservation = xfs_ag_resv_needed(pag, args->resv);
 
 	/* do we have enough contiguous free space for the allocation? */
+	alloc_len = args->minlen + (args->alignment - 1) + args->minalignslop;
 	longest = xfs_alloc_longest_free_extent(args->mp, pag, min_free,
 			reservation);
-	if ((args->minlen + args->alignment + args->minalignslop - 1) > longest)
+	if (longest < alloc_len)
 		return false;
 
 	/* do we have enough free space remaining for the allocation? */
 	available = (int)(pag->pagf_freeblks + pag->pagf_flcount -
 			  reservation - min_free - args->minleft);
-	if (available < (int)args->total)
+	if (available < (int)max(args->total, alloc_len))
 		return false;
 
 	/*