xfs: detect and repair misaligned rtinherit directory cowextsize hints

If we encounter a directory that has been configured to pass on a CoW
extent size hint to a new realtime file and the hint isn't an integer
multiple of the rt extent size, we should flag the hint for
administrative review and/or turn it off because that is a
misconfiguration.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>

2 files changed, 32 insertions, 9 deletions

diff --git a/fs/xfs/scrub/inode.c b/fs/xfs/scrub/inode.c
index 6f88b3ced3ed..f31eb0838402 100644
--- a/fs/xfs/scrub/inode.c
+++ b/fs/xfs/scrub/inode.c
@@ -224,12 +224,7 @@ xchk_inode_extsize(
 		xchk_ino_set_warning(sc, ino);
 }
 
-/*
- * Validate di_cowextsize hint.
- *
- * The rules are documented at xfs_ioctl_setattr_check_cowextsize().
- * These functions must be kept in sync with each other.
- */
+/* Validate di_cowextsize hint. */
 STATIC void
 xchk_inode_cowextsize(
 	struct xfs_scrub	*sc,
@@ -240,12 +235,25 @@ xchk_inode_cowextsize(
 	uint64_t		flags2)
 {
 	xfs_failaddr_t		fa;
+	uint32_t		value = be32_to_cpu(dip->di_cowextsize);
 
-	fa = xfs_inode_validate_cowextsize(sc->mp,
-			be32_to_cpu(dip->di_cowextsize), mode, flags,
-			flags2);
+	fa = xfs_inode_validate_cowextsize(sc->mp, value, mode, flags, flags2);
 	if (fa)
 		xchk_ino_set_corrupt(sc, ino);
+
+	/*
+	 * XFS allows a sysadmin to change the rt extent size when adding a rt
+	 * section to a filesystem after formatting.  If there are any
+	 * directories with cowextsize and rtinherit set, the hint could become
+	 * misaligned with the new rextsize.  The verifier doesn't check this,
+	 * because we allow rtinherit directories even without an rt device.
+	 * Flag this as an administrative warning since we will clean this up
+	 * eventually.
+	 */
+	if ((flags & XFS_DIFLAG_RTINHERIT) &&
+	    (flags2 & XFS_DIFLAG2_COWEXTSIZE) &&
+	    value % sc->mp->m_sb.sb_rextsize > 0)
+		xchk_ino_set_warning(sc, ino);
 }
 
 /* Make sure the di_flags make sense for the inode. */
diff --git a/fs/xfs/scrub/inode_repair.c b/fs/xfs/scrub/inode_repair.c
index 7def9bf4e92e..56fec323042c 100644
--- a/fs/xfs/scrub/inode_repair.c
+++ b/fs/xfs/scrub/inode_repair.c
@@ -1568,6 +1568,20 @@ xrep_inode_extsize(
 	}
 }
 
+/* Fix COW extent size hint problems. */
+STATIC void
+xrep_inode_cowextsize(
+	struct xfs_scrub	*sc)
+{
+	/* Fix misaligned CoW extent size hints on a directory. */
+	if ((sc->ip->i_diflags & XFS_DIFLAG_RTINHERIT) &&
+	    (sc->ip->i_diflags2 & XFS_DIFLAG2_COWEXTSIZE) &&
+	    sc->ip->i_extsize % sc->mp->m_sb.sb_rextsize > 0) {
+		sc->ip->i_cowextsize = 0;
+		sc->ip->i_diflags2 &= ~XFS_DIFLAG2_COWEXTSIZE;
+	}
+}
+
 /* Fix any irregularities in an inode that the verifiers don't catch. */
 STATIC int
 xrep_inode_problems(
@@ -1583,6 +1597,7 @@ xrep_inode_problems(
 	xrep_inode_ids(sc);
 	xrep_inode_size(sc);
 	xrep_inode_extsize(sc);
+	xrep_inode_cowextsize(sc);
 
 	trace_xrep_inode_fixed(sc);
 	xfs_trans_log_inode(sc->tp, sc->ip, XFS_ILOG_CORE);