ext4: Don't update superblock write time when filesystem is read-only

This avoids updating the superblock write time when we are mounting
the root file system read/only but we need to replay the journal; at
that point, for people who are east of GMT and who make their clock
tick in localtime for Windows bug-for-bug compatibility, and this will
cause e2fsck to complain and force a full file system check.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

1 files changed, 12 insertions, 1 deletions

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index f1815d3bcfd5..9f6fa3f74629 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -3222,7 +3222,18 @@ static int ext4_commit_super(struct super_block *sb, int sync)
                 clear_buffer_write_io_error(sbh);
                 set_buffer_uptodate(sbh);
         }
-        es->s_wtime = cpu_to_le32(get_seconds());
+        /*
+         * If the file system is mounted read-only, don't update the
+         * superblock write time.  This avoids updating the superblock
+         * write time when we are mounting the root file system
+         * read/only but we need to replay the journal; at that point,
+         * for people who are east of GMT and who make their clock
+         * tick in localtime for Windows bug-for-bug compatibility,
+         * the clock is set in the future, and this will cause e2fsck
+         * to complain and force a full file system check.
+         */
+        if (!(sb->s_flags & MS_RDONLY))
+                es->s_wtime = cpu_to_le32(get_seconds());
         es->s_kbytes_written =
                 cpu_to_le64(EXT4_SB(sb)->s_kbytes_written + 
                             ((part_stat_read(sb->s_bdev->bd_part, sectors[1]) -