From: Darrick J. Wong <djwong@kernel.org>
Date: Fri, 7 Mar 2025 17:55:01 +0000 (-0800)
Subject: xfs_{admin,repair},man5: tell the user to mount with nouuid for snapshots
X-Git-Tag: v6.14.0~18
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=c34735adb5116b4edae110d788c44d2462017765;p=thirdparty%2Fxfsprogs-dev.git

xfs_{admin,repair},man5: tell the user to mount with nouuid for snapshots

Augment the messaging in xfs_admin and xfs_repair to advise the user to
replay a dirty log on a snapshotted filesystem by mounting with nouuid
if the origin filesystem is still mounted.  A user accidentally zapped
the log when trying to mount a backup snapshot because the instructions
we gave them weren't sufficient.

Reported-by: Kjetil Torgrim Homme <kjetilho@ifi.uio.no>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
Reviewed-by: Bill O'Donnell <bodonnel@redhat.com>
[add missing whitespace in 'the nouuid option.If you are']
---

diff --git a/db/sb.c b/db/sb.c
index aa8fce671..52ac48d45 100644
--- a/db/sb.c
+++ b/db/sb.c
@@ -266,10 +266,11 @@ sb_logcheck(void)
 		dbprintf(_(
 "ERROR: The filesystem has valuable metadata changes in a log which needs to\n"
 "be replayed.  Mount the filesystem to replay the log, and unmount it before\n"
-"re-running %s.  If you are unable to mount the filesystem, then use\n"
-"the xfs_repair -L option to destroy the log and attempt a repair.\n"
-"Note that destroying the log may cause corruption -- please attempt a mount\n"
-"of the filesystem before doing this.\n"), progname);
+"re-running %s.  If the filesystem is a snapshot of a mounted filesystem,\n"
+"you may need to give mount the nouuid option.  If you are unable to mount\n"
+"the filesystem, then use the xfs_repair -L option to destroy the log and\n"
+"attempt a repair.  Note that destroying the log may cause corruption --\n"
+"please attempt a mount of the filesystem before doing this.\n"), progname);
 		return 0;
 	}
 	/* Log is clean */
diff --git a/man/man5/xfs.5 b/man/man5/xfs.5
index 0c1edc53e..f9c046d47 100644
--- a/man/man5/xfs.5
+++ b/man/man5/xfs.5
@@ -91,6 +91,11 @@ may become confused when doing incremental and resumed dumps.
 and
 .BR xfsrestore (8)
 are recommended for making copies of XFS filesystems.
+To mount a snapshot of an already-mounted filesystem, you may need to supply
+the
+.B nouuid
+option to
+.BR mount " (8)."
 .SH OPERATIONS
 Some functionality specific to the XFS filesystem is accessible to
 applications through the
diff --git a/repair/phase2.c b/repair/phase2.c
index 71576f580..e24998052 100644
--- a/repair/phase2.c
+++ b/repair/phase2.c
@@ -72,10 +72,11 @@ zero_log(
 				do_warn(_(
 "ERROR: The filesystem has valuable metadata changes in a log which needs to\n"
 "be replayed.  Mount the filesystem to replay the log, and unmount it before\n"
-"re-running xfs_repair.  If you are unable to mount the filesystem, then use\n"
-"the -L option to destroy the log and attempt a repair.\n"
-"Note that destroying the log may cause corruption -- please attempt a mount\n"
-"of the filesystem before doing this.\n"));
+"re-running xfs_repair.  If the filesystem is a snapshot of a mounted\n"
+"filesystem, you may need to give mount the nouuid option. If you are unable\n"
+"to mount the filesystem, then use the -L option to destroy the log and\n"
+"attempt a repair.  Note that destroying the log may cause corruption --\n"
+"please attempt a mount of the filesystem before doing this.\n"));
 				exit(2);
 			}
 		}