[PATCH 2/3] xfs_repair: warn about unwritten bits set in rmap btree keys

["Darrick J. Wong" <djwong@kernel.org>]

From: Darrick J. Wong <djwong@kernel.org>

Now that we've changed libxfs to handle the rmapbt flags correctly when
creating and comparing rmapbt keys, teach repair to warn about keys that
have the unwritten bit erroneously set.  The old broken behavior never
caused any problems, so we only warn once per filesystem and don't set
the exitcode to 1 if we're running in dry run mode.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
---
 repair/scan.c |   28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)


diff --git a/repair/scan.c b/repair/scan.c
index d66ce60cbb3..008ef65ac75 100644
--- a/repair/scan.c
+++ b/repair/scan.c
@@ -966,6 +966,30 @@ verify_rmap_agbno(
 	return agbno < libxfs_ag_block_count(mp, agno);
 }
 
+static inline void
+warn_rmap_unwritten_key(
+	xfs_agblock_t		agno)
+{
+	static bool		warned = false;
+	static pthread_mutex_t	lock = PTHREAD_MUTEX_INITIALIZER;
+
+	if (warned)
+		return;
+
+	pthread_mutex_lock(&lock);
+	if (!warned) {
+		if (no_modify)
+			do_log(
+ _("would clear unwritten flag on rmapbt key in agno 0x%x\n"),
+			       agno);
+		else
+			do_warn(
+ _("clearing unwritten flag on rmapbt key in agno 0x%x\n"),
+			       agno);
+		warned = true;
+	}
+	pthread_mutex_unlock(&lock);
+}
 
 static void
 scan_rmapbt(
@@ -1218,6 +1242,8 @@ _("%s rmap btree block claimed (state %d), agno %d, bno %d, suspect %d\n"),
 		key.rm_flags = 0;
 		key.rm_startblock = be32_to_cpu(kp->rm_startblock);
 		key.rm_owner = be64_to_cpu(kp->rm_owner);
+		if (kp->rm_offset & cpu_to_be64(XFS_RMAP_OFF_UNWRITTEN))
+			warn_rmap_unwritten_key(agno);
 		if (libxfs_rmap_irec_offset_unpack(be64_to_cpu(kp->rm_offset),
 				&key)) {
 			/* Look for impossible flags. */
@@ -1239,6 +1265,8 @@ _("%s rmap btree block claimed (state %d), agno %d, bno %d, suspect %d\n"),
 		key.rm_flags = 0;
 		key.rm_startblock = be32_to_cpu(kp->rm_startblock);
 		key.rm_owner = be64_to_cpu(kp->rm_owner);
+		if (kp->rm_offset & cpu_to_be64(XFS_RMAP_OFF_UNWRITTEN))
+			warn_rmap_unwritten_key(agno);
 		if (libxfs_rmap_irec_offset_unpack(be64_to_cpu(kp->rm_offset),
 				&key)) {
 			/* Look for impossible flags. */