ubi: Fix race condition between ubi device creation and udev

[pandora-kernel.git] / fs / jbd / checkpoint.c

diff --git a/fs/jbd/checkpoint.c b/fs/jbd/checkpoint.c
index f94fc48..5c93ffc 100644 (file)
--- a/fs/jbd/checkpoint.c
+++ b/fs/jbd/checkpoint.c
@@ -453,8 +453,6 @@ out:
  *
  * Return <0 on error, 0 on success, 1 if there was nothing to clean up.
  *
- * Called with the journal lock held.
- *
  * This is the only part of the journaling code which really needs to be
  * aware of transaction aborts.  Checkpointing involves writing to the
  * main filesystem area rather than to the journal, so it can proceed
@@ -472,13 +470,14 @@ int cleanup_journal_tail(journal_t *journal)
        if (is_journal_aborted(journal))
                return 1;
 
-       /* OK, work out the oldest transaction remaining in the log, and
+       /*
+        * OK, work out the oldest transaction remaining in the log, and
         * the log block it starts at.
         *
         * If the log is now empty, we need to work out which is the
         * next transaction ID we will write, and where it will
-        * start. */
-
+        * start.
+        */
        spin_lock(&journal->j_state_lock);
        spin_lock(&journal->j_list_lock);
        transaction = journal->j_checkpoint_transactions;
@@ -504,7 +503,25 @@ int cleanup_journal_tail(journal_t *journal)
                spin_unlock(&journal->j_state_lock);
                return 1;
        }
+       spin_unlock(&journal->j_state_lock);
+
+       /*
+        * We need to make sure that any blocks that were recently written out
+        * --- perhaps by log_do_checkpoint() --- are flushed out before we
+        * drop the transactions from the journal. It's unlikely this will be
+        * necessary, especially with an appropriately sized journal, but we
+        * need this to guarantee correctness.  Fortunately
+        * cleanup_journal_tail() doesn't get called all that often.
+        */
+       if (journal->j_flags & JFS_BARRIER)
+               blkdev_issue_flush(journal->j_fs_dev, GFP_KERNEL, NULL);
 
+       spin_lock(&journal->j_state_lock);
+       if (!tid_gt(first_tid, journal->j_tail_sequence)) {
+               spin_unlock(&journal->j_state_lock);
+               /* Someone else cleaned up journal so return 0 */
+               return 0;
+       }
        /* OK, update the superblock to recover the freed space.
         * Physical blocks come first: have we wrapped beyond the end of
         * the log?  */