Patch "xfs: reset rootdir extent size hint after growfsrt" has been added to the 6.6-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

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

    xfs: reset rootdir extent size hint after growfsrt

to the 6.6-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-reset-rootdir-extent-size-hint-after-growfsrt.patch
and it can be found in the queue-6.6 subdirectory.

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



commit ef5cc24203d66661303c0dbd7315c2667d52886b
Author: Darrick J. Wong <djwong@xxxxxxxxxx>
Date:   Wed Dec 18 11:17:25 2024 -0800

    xfs: reset rootdir extent size hint after growfsrt
    
    commit a24cae8fc1f13f6f6929351309f248fd2e9351ce upstream.
    
    If growfsrt is run on a filesystem that doesn't have a rt volume, it's
    possible to change the rt extent size.  If the root directory was
    previously set up with an inherited extent size hint and rtinherit, it's
    possible that the hint is no longer a multiple of the rt extent size.
    Although the verifiers don't complain about this, xfs_repair will, so if
    we detect this situation, log the root directory to clean it up.  This
    is still racy, but it's better than nothing.
    
    Reviewed-by: Christoph Hellwig <hch@xxxxxx>
    Signed-off-by: Darrick J. Wong <djwong@xxxxxxxxxx>
    Signed-off-by: Chandan Babu R <chandanbabu@xxxxxxxxxx>
    Signed-off-by: Catherine Hoang <catherine.hoang@xxxxxxxxxx>
    Acked-by: Darrick J. Wong <djwong@xxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/fs/xfs/xfs_rtalloc.c b/fs/xfs/xfs_rtalloc.c
index 9268961d887c..ad828fbd5ce4 100644
--- a/fs/xfs/xfs_rtalloc.c
+++ b/fs/xfs/xfs_rtalloc.c
@@ -915,6 +915,39 @@ xfs_alloc_rsum_cache(
 		xfs_warn(mp, "could not allocate realtime summary cache");
 }
 
+/*
+ * If we changed the rt extent size (meaning there was no rt volume previously)
+ * and the root directory had EXTSZINHERIT and RTINHERIT set, it's possible
+ * that the extent size hint on the root directory is no longer congruent with
+ * the new rt extent size.  Log the rootdir inode to fix this.
+ */
+static int
+xfs_growfs_rt_fixup_extsize(
+	struct xfs_mount	*mp)
+{
+	struct xfs_inode	*ip = mp->m_rootip;
+	struct xfs_trans	*tp;
+	int			error = 0;
+
+	xfs_ilock(ip, XFS_IOLOCK_EXCL);
+	if (!(ip->i_diflags & XFS_DIFLAG_RTINHERIT) ||
+	    !(ip->i_diflags & XFS_DIFLAG_EXTSZINHERIT))
+		goto out_iolock;
+
+	error = xfs_trans_alloc_inode(ip, &M_RES(mp)->tr_ichange, 0, 0, false,
+			&tp);
+	if (error)
+		goto out_iolock;
+
+	xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
+	error = xfs_trans_commit(tp);
+	xfs_iunlock(ip, XFS_ILOCK_EXCL);
+
+out_iolock:
+	xfs_iunlock(ip, XFS_IOLOCK_EXCL);
+	return error;
+}
+
 /*
  * Visible (exported) functions.
  */
@@ -944,6 +977,7 @@ xfs_growfs_rt(
 	xfs_sb_t	*sbp;		/* old superblock */
 	xfs_fsblock_t	sumbno;		/* summary block number */
 	uint8_t		*rsum_cache;	/* old summary cache */
+	xfs_agblock_t	old_rextsize = mp->m_sb.sb_rextsize;
 
 	sbp = &mp->m_sb;
 
@@ -1177,6 +1211,12 @@ xfs_growfs_rt(
 	if (error)
 		goto out_free;
 
+	if (old_rextsize != in->extsize) {
+		error = xfs_growfs_rt_fixup_extsize(mp);
+		if (error)
+			goto out_free;
+	}
+
 	/* Update secondary superblocks now the physical grow has completed */
 	error = xfs_update_secondary_sbs(mp);