Patch "xfs: don't skip free extents of the longest length in a whole-AG FITRIM" has been added to the 7.3-stable tree

Patch "xfs: don't skip free extents of the longest length in a whole-AG FITRIM" has been added to the 7.3-stable tree

[Sasha Levin]

This is a note to let you know that I've just added the patch titled

    xfs: don't skip free extents of the longest length in a whole-AG FITRIM

to the 7.3-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     xfs-don-t-skip-free-extents-of-the-longest-length-in.patch
and it can be found in the queue-7.3 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.



commit 9661004d580814f4be2838b1020ab0123f4da2b4
Author: Daejun Park <daejun7.park@samsung.com>
Date:   Mon Oct 26 10:54:06 2026 +0900

    xfs: don't skip free extents of the longest length in a whole-AG FITRIM
    
    [ Upstream commit 5745f4f10a1a16aa5bb020acc38afa33f2d5ff99 ]
    
    Since commit a66d636385d6 ("xfs: fix fstrim offset calculations"), the
    by-length walk of an AG in FITRIM starts with
    xfs_alloc_lookup_ge(cur, 0, pagf_longest) and walks down. The lookup
    lands on the longest free extent with the lowest block number. The
    other free extents of that length sort after it and are never
    discarded.
    
    Start every by-length batch with xfs_alloc_lookup_le() at restart_bno.
    
    Suggested-by: Dave Chinner <dgc@kernel.org>
    Link: https://lore.kernel.org/r/ZgiJWxVcVwag0fIP@dread.disaster.area
    Cc: stable@vger.kernel.org
    Fixes: a66d636385d6 ("xfs: fix fstrim offset calculations")
    Signed-off-by: Daejun Park <daejun7.park@samsung.com>
    Reviewed-by: Christoph Hellwig <hch@lst.de>
    Signed-off-by: Carlos Maiolino <cem@kernel.org>
    Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/fs/xfs/xfs_discard.c b/fs/xfs/xfs_discard.c
index 8120f136af931..cdf660344c281 100644
--- a/fs/xfs/xfs_discard.c
+++ b/fs/xfs/xfs_discard.c
@@ -200,12 +200,12 @@ xfs_trim_gather_extents(
 		error = xfs_alloc_lookup_le(cur, tcur->start, 0, &i);
 		if (!error && !i)
 			error = xfs_alloc_lookup_ge(cur, tcur->start, 0, &i);
-	} else if (tcur->restart_bno == NULLAGBLOCK) {
-		/* first time through a by-len starts with max length */
-		cur = xfs_cntbt_init_cursor(mp, tp, agbp, pag);
-		error = xfs_alloc_lookup_ge(cur, 0, tcur->count, &i);
 	} else {
-		/* nth time through a by-len starts where we left off */
+		/*
+		 * A by-len walk starts at the last record of the longest
+		 * length (restart_bno is NULLAGBLOCK until the first batch
+		 * ends) and then where the previous batch stopped.
+		 */
 		cur = xfs_cntbt_init_cursor(mp, tp, agbp, pag);
 		error = xfs_alloc_lookup_le(cur, tcur->restart_bno,
 					    tcur->count, &i);