5 files changed, 65 insertions, 39 deletions

diff --git a/fs/jbd/checkpoint.c b/fs/jbd/checkpoint.c
index 80c85f3e087f..08c03044abdd 100644
--- a/fs/jbd/checkpoint.c
+++ b/fs/jbd/checkpoint.c
@@ -508,20 +508,19 @@ int cleanup_journal_tail(journal_t *journal)
         /*
          * 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.
+         * drop the transactions from the journal. Similarly we need to be sure
+         * superblock makes it to disk before next transaction starts reusing
+         * freed space (otherwise we could replay some blocks of the new
+         * transaction thinking they belong to the old one). So we use
+         * WRITE_FLUSH_FUA. 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);
+        journal_update_sb_log_tail(journal, first_tid, blocknr,
+                                   WRITE_FLUSH_FUA);
 
         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?  */
@@ -539,8 +538,6 @@ int cleanup_journal_tail(journal_t *journal)
         journal->j_tail_sequence = first_tid;
         journal->j_tail = blocknr;
         spin_unlock(&journal->j_state_lock);
-        if (!(journal->j_flags & JFS_ABORT))
-                journal_update_sb_log_tail(journal);
         return 0;
 }
 
diff --git a/fs/jbd/commit.c b/fs/jbd/commit.c
index 1b27f46e6108..52c15c776029 100644
--- a/fs/jbd/commit.c
+++ b/fs/jbd/commit.c
@@ -309,7 +309,14 @@ void journal_commit_transaction(journal_t *journal)
         if (journal->j_flags & JFS_FLUSHED) {
                 jbd_debug(3, "super block updated\n");
                 mutex_lock(&journal->j_checkpoint_mutex);
-                journal_update_sb_log_tail(journal);
+                /*
+                 * We hold j_checkpoint_mutex so tail cannot change under us.
+                 * We don't need any special data guarantees for writing sb
+                 * since journal is empty and it is ok for write to be
+                 * flushed only with transaction commit.
+                 */
+                journal_update_sb_log_tail(journal, journal->j_tail_sequence,
+                                           journal->j_tail, WRITE_SYNC);
                 mutex_unlock(&journal->j_checkpoint_mutex);
         } else {
                 jbd_debug(3, "superblock not updated\n");
diff --git a/fs/jbd/journal.c b/fs/jbd/journal.c
index b29c7678525d..425c2f2cf170 100644
--- a/fs/jbd/journal.c
+++ b/fs/jbd/journal.c
@@ -938,8 +938,16 @@ static int journal_reset(journal_t *journal)
         } else {
                 /* Lock here to make assertions happy... */
                 mutex_lock(&journal->j_checkpoint_mutex);
-                /* Add the dynamic fields and write it to disk. */
-                journal_update_sb_log_tail(journal);
+                /*
+                 * Update log tail information. We use WRITE_FUA since new
+                 * transaction will start reusing journal space and so we
+                 * must make sure information about current log tail is on
+                 * disk before that.
+                 */
+                journal_update_sb_log_tail(journal,
+                                           journal->j_tail_sequence,
+                                           journal->j_tail,
+                                           WRITE_FUA);
                 mutex_unlock(&journal->j_checkpoint_mutex);
         }
         return journal_start_thread(journal);
@@ -1018,11 +1026,15 @@ int journal_create(journal_t *journal)
         return journal_reset(journal);
 }
 
-static void journal_write_superblock(journal_t *journal)
+static void journal_write_superblock(journal_t *journal, int write_op)
 {
         struct buffer_head *bh = journal->j_sb_buffer;
+        int ret;
 
-        trace_journal_write_superblock(journal);
+        trace_journal_write_superblock(journal, write_op);
+        if (!(journal->j_flags & JFS_BARRIER))
+                write_op &= ~(REQ_FUA | REQ_FLUSH);
+        lock_buffer(bh);
         if (buffer_write_io_error(bh)) {
                 char b[BDEVNAME_SIZE];
                 /*
@@ -1040,40 +1052,46 @@ static void journal_write_superblock(journal_t *journal)
                 set_buffer_uptodate(bh);
         }
 
-        BUFFER_TRACE(bh, "marking dirty");
-        mark_buffer_dirty(bh);
-        sync_dirty_buffer(bh);
+        get_bh(bh);
+        bh->b_end_io = end_buffer_write_sync;
+        ret = submit_bh(write_op, bh);
+        wait_on_buffer(bh);
         if (buffer_write_io_error(bh)) {
-                char b[BDEVNAME_SIZE];
-                printk(KERN_ERR "JBD: I/O error detected "
-                       "when updating journal superblock for %s.\n",
-                       journal_dev_name(journal, b));
                 clear_buffer_write_io_error(bh);
                 set_buffer_uptodate(bh);
+                ret = -EIO;
+        }
+        if (ret) {
+                char b[BDEVNAME_SIZE];
+                printk(KERN_ERR "JBD: Error %d detected "
+                       "when updating journal superblock for %s.\n",
+                       ret, journal_dev_name(journal, b));
         }
 }
 
 /**
  * journal_update_sb_log_tail() - Update log tail in journal sb on disk.
  * @journal: The journal to update.
+ * @tail_tid: TID of the new transaction at the tail of the log
+ * @tail_block: The first block of the transaction at the tail of the log
+ * @write_op: With which operation should we write the journal sb
  *
  * Update a journal's superblock information about log tail and write it to
  * disk, waiting for the IO to complete.
  */
-void journal_update_sb_log_tail(journal_t *journal)
+void journal_update_sb_log_tail(journal_t *journal, tid_t tail_tid,
+                                unsigned int tail_block, int write_op)
 {
         journal_superblock_t *sb = journal->j_superblock;
 
         BUG_ON(!mutex_is_locked(&journal->j_checkpoint_mutex));
-        spin_lock(&journal->j_state_lock);
-        jbd_debug(1,"JBD: updating superblock (start %u, seq %d, errno %d)\n",
-                  journal->j_tail, journal->j_tail_sequence, journal->j_errno);
+        jbd_debug(1,"JBD: updating superblock (start %u, seq %u)\n",
+                  tail_block, tail_tid);
 
-        sb->s_sequence = cpu_to_be32(journal->j_tail_sequence);
-        sb->s_start    = cpu_to_be32(journal->j_tail);
-        spin_unlock(&journal->j_state_lock);
+        sb->s_sequence = cpu_to_be32(tail_tid);
+        sb->s_start    = cpu_to_be32(tail_block);
 
-        journal_write_superblock(journal);
+        journal_write_superblock(journal, write_op);
 
         /* Log is no longer empty */
         spin_lock(&journal->j_state_lock);
@@ -1102,7 +1120,7 @@ static void mark_journal_empty(journal_t *journal)
         sb->s_start    = cpu_to_be32(0);
         spin_unlock(&journal->j_state_lock);
 
-        journal_write_superblock(journal);
+        journal_write_superblock(journal, WRITE_FUA);
 
         spin_lock(&journal->j_state_lock);
         /* Log is empty */
@@ -1127,7 +1145,7 @@ static void journal_update_sb_errno(journal_t *journal)
         sb->s_errno = cpu_to_be32(journal->j_errno);
         spin_unlock(&journal->j_state_lock);
 
-        journal_write_superblock(journal);
+        journal_write_superblock(journal, WRITE_SYNC);
 }
 
 /*
diff --git a/include/linux/jbd.h b/include/linux/jbd.h
index 9716d370c501..c8f32975f0e4 100644
--- a/include/linux/jbd.h
+++ b/include/linux/jbd.h
@@ -864,7 +864,8 @@ extern int	   journal_destroy    (journal_t *);
 extern int         journal_recover    (journal_t *journal);
 extern int         journal_wipe       (journal_t *, int);
 extern int         journal_skip_recovery        (journal_t *);
-extern void        journal_update_sb_log_tail   (journal_t *);
+extern void        journal_update_sb_log_tail   (journal_t *, tid_t, unsigned int,
+                                                 int);
 extern void        journal_abort      (journal_t *, int);
 extern int         journal_errno      (journal_t *);
 extern void        journal_ack_err    (journal_t *);
diff --git a/include/trace/events/jbd.h b/include/trace/events/jbd.h
index d9658a940a39..da6f2591c25e 100644
--- a/include/trace/events/jbd.h
+++ b/include/trace/events/jbd.h
@@ -170,19 +170,22 @@ TRACE_EVENT(jbd_cleanup_journal_tail,
 );
 
 TRACE_EVENT(journal_write_superblock,
-        TP_PROTO(journal_t *journal),
+        TP_PROTO(journal_t *journal, int write_op),
 
-        TP_ARGS(journal),
+        TP_ARGS(journal, write_op),
 
         TP_STRUCT__entry(
                 __field(        dev_t,  dev                     )
+                __field(        int,    write_op                )
         ),
 
         TP_fast_assign(
                 __entry->dev            = journal->j_fs_dev->bd_dev;
+                __entry->write_op       = write_op;
         ),
 
-        TP_printk("dev %d,%d", MAJOR(__entry->dev), MINOR(__entry->dev))
+        TP_printk("dev %d,%d write_op %x", MAJOR(__entry->dev),
+                  MINOR(__entry->dev), __entry->write_op)
 );
 
 #endif /* _TRACE_JBD_H */