When gfs2 was mounted read-only and then unmounted, it was writing a header block to the journal in the syncing gfs2_log_flush() call from kill_sb(). This is because the journal was not being marked as idle until the first log header was written out, and on a read-only mount there never was a log header written out. Since the journal was not marked idle, gfs2_log_flush() was writing out a header lock to make sure it was empty during the sync. Not only did this cause IO to a read-only filesystem, but the journalling isn't completely initialized on read-only mounts, and so gfs2 was writing out the wrong sequence number in the log header.
Now, the journal is marked idle on mount, and gfs2_log_flush() won't write out anything until there starts being transactions to flush. Signed-off-by: Benjamin Marzinski <bmarz...@redhat.com> --- fs/gfs2/ops_fstype.c | 1 + 1 file changed, 1 insertion(+) diff --git a/fs/gfs2/ops_fstype.c b/fs/gfs2/ops_fstype.c index 8633ad3..fd984f6 100644 --- a/fs/gfs2/ops_fstype.c +++ b/fs/gfs2/ops_fstype.c @@ -757,6 +757,7 @@ static int init_journal(struct gfs2_sbd *sdp, int undo) } } + sdp->sd_log_idle = 1; set_bit(SDF_JOURNAL_CHECKED, &sdp->sd_flags); gfs2_glock_dq_uninit(&ji_gh); jindex = 0; -- 1.8.3.1