From: David Sterba <dsterba@suse.com>
Date: Wed, 5 Feb 2020 16:12:28 +0000 (+0100)
Subject: btrfs: log message when rw remount is attempted with unclean tree-log
X-Git-Tag: v4.19.105~20
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=a3eccdff2ce26a09a2ee4bb21ea453c5e4af303b;p=thirdparty%2Fkernel%2Fstable.git

btrfs: log message when rw remount is attempted with unclean tree-log

commit 10a3a3edc5b89a8cd095bc63495fb1e0f42047d9 upstream.

A remount to a read-write filesystem is not safe when there's tree-log
to be replayed. Files that could be opened until now might be affected
by the changes in the tree-log.

A regular mount is needed to replay the log so the filesystem presents
the consistent view with the pending changes included.

CC: stable@vger.kernel.org # 4.4+
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index db4002ecbaca3..6a5b16a119eda 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -1857,6 +1857,8 @@ static int btrfs_remount(struct super_block *sb, int *flags, char *data)
 		}
 
 		if (btrfs_super_log_root(fs_info->super_copy) != 0) {
+			btrfs_warn(fs_info,
+		"mount required to replay tree-log, cannot remount read-write");
 			ret = -EINVAL;
 			goto restore;
 		}