Xen doesn't report that barriers are not supported until buffer I/O is
reported as completed, instead of when the buffer I/O is submitted.
Add a check and a fallback codepath to journal_wait_on_commit_record()
to detect this case, so that attempts to mount ext4 filesystems on
LVM/devicemapper devices on Xen guests don't blow up with an "Aborting
journal on device XXX"; "Remounting filesystem read-only" error.
Thanks to Andreas Sundstrom for reporting this issue.
Signed-off-by: "Theodore Ts'o" <tytso@xxxxxxx>
Cc: stable@xxxxxxxxxx
(cherry picked from commit fd98496f467b3d26d05ab1498f41718b5ef13de5)
---
fs/jbd2/commit.c | 27 +++++++++++++++++++++++++--
1 files changed, 25 insertions(+), 2 deletions(-)
diff --git a/fs/jbd2/commit.c b/fs/jbd2/commit.c
index ebc667b..6393fd0 100644
--- a/fs/jbd2/commit.c
+++ b/fs/jbd2/commit.c
@@ -25,6 +25,7 @@
#include <linux/crc32.h>
#include <linux/writeback.h>
#include <linux/backing-dev.h>
+#include <linux/bio.h>
/*
* Default IO end handler for temporary BJ_IO buffer_heads.
@@ -168,12 +169,34 @@ static int journal_submit_commit_record(journal_t *journal,
* This function along with journal_submit_commit_record
* allows to write the commit record asynchronously.
*/
-static int journal_wait_on_commit_record(struct buffer_head *bh)
+static int journal_wait_on_commit_record(journal_t *journal,
+ struct buffer_head *bh)
{
int ret = 0;
+retry:
clear_buffer_dirty(bh);
wait_on_buffer(bh);
+ if (buffer_eopnotsupp(bh) && (journal->j_flags & JBD2_BARRIER)) {
+ printk(KERN_WARNING
+ "JBD2: wait_on_commit_record: sync failed on %s - "
+ "disabling barriers\n", journal->j_devname);
+ spin_lock(&journal->j_state_lock);
+ journal->j_flags &= ~JBD2_BARRIER;
+ spin_unlock(&journal->j_state_lock);
+
+ lock_buffer(bh);
+ clear_buffer_dirty(bh);
+ set_buffer_uptodate(bh);
+ bh->b_end_io = journal_end_buffer_io_sync;
+
+ ret = submit_bh(WRITE_SYNC, bh);
+ if (ret) {
+ unlock_buffer(bh);
+ return ret;
+ }
+ goto retry;
+ }
if (unlikely(!buffer_uptodate(bh)))
ret = -EIO;
@@ -799,7 +822,7 @@ wait_for_iobuf:
__jbd2_journal_abort_hard(journal);
}
if (!err && !is_journal_aborted(journal))
- err = journal_wait_on_commit_record(cbh);
+ err = journal_wait_on_commit_record(journal, cbh);
if (err)
jbd2_journal_abort(journal, err);
--
1.5.6.3
--
To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
