linux-kernel - [PATCH 12/13] xfs: Don't revert allocated offset for forcealign

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Date: Fri, 21 Jun 2024 10:05:39 +0000
From: John Garry <john.g.garry@...cle.com>
To: chandan.babu@...cle.com, djwong@...nel.org, dchinner@...hat.com,
        hch@....de
Cc: viro@...iv.linux.org.uk, brauner@...nel.org, jack@...e.cz,
        linux-xfs@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-fsdevel@...r.kernel.org, catherine.hoang@...cle.com,
        martin.petersen@...cle.com, John Garry <john.g.garry@...cle.com>
Subject: [PATCH 12/13] xfs: Don't revert allocated offset for forcealign

In xfs_bmap_process_allocated_extent(), for when we found that we could not
provide the requested length completely, the mapping is moved so that we
can provide as much as possible for the original request.

For forcealign, this would mean ignoring alignment guaranteed, so don't do
this.

Signed-off-by: John Garry <john.g.garry@...cle.com>
---
 fs/xfs/libxfs/xfs_bmap.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
index ebeb2969b289..42f3582c1574 100644
--- a/fs/xfs/libxfs/xfs_bmap.c
+++ b/fs/xfs/libxfs/xfs_bmap.c
@@ -3492,11 +3492,15 @@ xfs_bmap_process_allocated_extent(
 	 * original request as possible.  Free space is apparently
 	 * very fragmented so we're unlikely to be able to satisfy the
 	 * hints anyway.
+	 * However, for an inode with forcealign, continue with the
+	 * found offset as we need to honour the alignment hint.
 	 */
-	if (ap->length <= orig_length)
-		ap->offset = orig_offset;
-	else if (ap->offset + ap->length < orig_offset + orig_length)
-		ap->offset = orig_offset + orig_length - ap->length;
+	if (!xfs_inode_has_forcealign(ap->ip)) {
+		if (ap->length <= orig_length)
+			ap->offset = orig_offset;
+		else if (ap->offset + ap->length < orig_offset + orig_length)
+			ap->offset = orig_offset + orig_length - ap->length;
+	}
 	xfs_bmap_alloc_account(ap);
 }
 
-- 
2.31.1