[PATCH 5/9] xfs: aligned EOF allocations don't need to scan AGs anymore

[Dave Chinner <david@fromorbit.com>]

From: Dave Chinner <dchinner@redhat.com>

Now that contiguous free space selection takes into account stripe
alignment, we no longer need to do an "all AGs" allocation scan in
the case the initial AG doesn't have enough contiguous free space
for a stripe aligned allocation. This cleans up
xfs_bmap_btalloc_aligned() the same for both filestreams and the
normal btree allocation code.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
 fs/xfs/libxfs/xfs_bmap.c | 40 +++++++++++++---------------------------
 1 file changed, 13 insertions(+), 27 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
index 3c250c89f42e..c1e2c0707e20 100644
--- a/fs/xfs/libxfs/xfs_bmap.c
+++ b/fs/xfs/libxfs/xfs_bmap.c
@@ -3538,10 +3538,8 @@ xfs_bmap_btalloc_aligned(
 	struct xfs_bmalloca	*ap,
 	struct xfs_alloc_arg	*args,
 	xfs_extlen_t		blen,
-	int			stripe_align,
-	bool			ag_only)
+	int			stripe_align)
 {
-	struct xfs_perag        *caller_pag = args->pag;
 	int			error;
 
 	/*
@@ -3558,14 +3556,7 @@ xfs_bmap_btalloc_aligned(
 	args->alignment = stripe_align;
 	args->minalignslop = 0;
 
-	if (ag_only) {
-		error = xfs_alloc_vextent_near_bno(args, ap->blkno);
-	} else {
-		args->pag = NULL;
-		error = xfs_alloc_vextent_start_ag(args, ap->blkno);
-		ASSERT(args->pag == NULL);
-		args->pag = caller_pag;
-	}
+	error = xfs_alloc_vextent_near_bno(args, ap->blkno);
 	if (error)
 		return error;
 
@@ -3650,8 +3641,7 @@ xfs_bmap_btalloc_filestreams(
 		goto out_low_space;
 
 	if (ap->aeof)
-		error = xfs_bmap_btalloc_aligned(ap, args, blen, stripe_align,
-				true);
+		error = xfs_bmap_btalloc_aligned(ap, args, blen, stripe_align);
 
 	if (!error && args->fsbno == NULLFSBLOCK)
 		error = xfs_alloc_vextent_near_bno(args, ap->blkno);
@@ -3715,9 +3705,16 @@ xfs_bmap_btalloc_best_length(
 		return error;
 	ASSERT(args->pag);
 
-	if (ap->aeof && ap->offset) {
+	if (ap->aeof && ap->offset)
 		error = xfs_bmap_btalloc_at_eof(ap, args, blen, stripe_align);
-	}
+
+	if (error || args->fsbno != NULLFSBLOCK)
+		goto out_perag_rele;
+
+
+	/* attempt aligned allocation for new EOF extents */
+	if (stripe_align)
+		error = xfs_bmap_btalloc_aligned(ap, args, blen, stripe_align);
 
 	/*
 	 * We are now done with the perag reference for the optimal allocation
@@ -3725,24 +3722,13 @@ xfs_bmap_btalloc_best_length(
 	 * now as we've either succeeded, had a fatal error or we are out of
 	 * space and need to do a full filesystem scan for free space which will
 	 * take it's own references.
-	 *
-	 * XXX: now that xfs_bmap_btalloc_select_lengths() selects an AG with
-	 * enough contiguous free space in it for an aligned allocation, we
-	 * can change the aligned allocation at EOF to just be a single AG
-	 * allocation.
 	 */
+out_perag_rele:
 	xfs_perag_rele(args->pag);
 	args->pag = NULL;
 	if (error || args->fsbno != NULLFSBLOCK)
 		return error;
 
-	/* attempt aligned allocation for new EOF extents */
-	if (stripe_align)
-		error = xfs_bmap_btalloc_aligned(ap, args, blen, stripe_align,
-				false);
-	if (error || args->fsbno != NULLFSBLOCK)
-		return error;
-
 	/* attempt unaligned allocation */
 	error = xfs_alloc_vextent_start_ag(args, ap->blkno);
 	if (error || args->fsbno != NULLFSBLOCK)
-- 
2.40.1