---

yaml
---
r: 296572
b: refs/heads/master
c: 79feb52
h: refs/heads/master
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: a78bb11d7acd525623c6a0c2ff4e213d527573fa
+refs/heads/master: 79feb521a44705262d15cc819a4117a447b11ea7

trunk/fs/jbd2/checkpoint.c

@@ -478,79 +478,28 @@ int jbd2_log_do_checkpoint(journal_t *journal)
 
 int jbd2_cleanup_journal_tail(journal_t *journal)
 {
-	transaction_t * transaction;
 	tid_t		first_tid;
-	unsigned long	blocknr, freed;
+	unsigned long	blocknr;
 
 	if (is_journal_aborted(journal))
 		return 1;
 
-	/* 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. */
-
-	write_lock(&journal->j_state_lock);
-	spin_lock(&journal->j_list_lock);
-	transaction = journal->j_checkpoint_transactions;
-	if (transaction) {
-		first_tid = transaction->t_tid;
-		blocknr = transaction->t_log_start;
-	} else if ((transaction = journal->j_committing_transaction) != NULL) {
-		first_tid = transaction->t_tid;
-		blocknr = transaction->t_log_start;
-	} else if ((transaction = journal->j_running_transaction) != NULL) {
-		first_tid = transaction->t_tid;
-		blocknr = journal->j_head;
-	} else {
-		first_tid = journal->j_transaction_sequence;
-		blocknr = journal->j_head;
-	}
-	spin_unlock(&journal->j_list_lock);
-	J_ASSERT(blocknr != 0);
-
-	/* If the oldest pinned transaction is at the tail of the log
-           already then there's not much we can do right now. */
-	if (journal->j_tail_sequence == first_tid) {
-		write_unlock(&journal->j_state_lock);
+	if (!jbd2_journal_get_log_tail(journal, &first_tid, &blocknr))
 		return 1;
-	}
-
-	/* OK, update the superblock to recover the freed space.
-	 * Physical blocks come first: have we wrapped beyond the end of
-	 * the log?  */
-	freed = blocknr - journal->j_tail;
-	if (blocknr < journal->j_tail)
-		freed = freed + journal->j_last - journal->j_first;
-
-	trace_jbd2_cleanup_journal_tail(journal, first_tid, blocknr, freed);
-	jbd_debug(1,
-		  "Cleaning journal tail from %d to %d (offset %lu), "
-		  "freeing %lu\n",
-		  journal->j_tail_sequence, first_tid, blocknr, freed);
-
-	journal->j_free += freed;
-	journal->j_tail_sequence = first_tid;
-	journal->j_tail = blocknr;
-	write_unlock(&journal->j_state_lock);
+	J_ASSERT(blocknr != 0);
 
 	/*
-	 * If there is an external journal, we need to make sure that
-	 * any data blocks that were recently written out --- perhaps
-	 * by jbd2_log_do_checkpoint() --- are flushed out before we
-	 * drop the transactions from the external journal.  It's
-	 * unlikely this will be necessary, especially with a
-	 * appropriately sized journal, but we need this to guarantee
-	 * correctness.  Fortunately jbd2_cleanup_journal_tail()
-	 * doesn't get called all that often.
+	 * We need to make sure that any blocks that were recently written out
+	 * --- perhaps by jbd2_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
+	 * jbd2_cleanup_journal_tail() doesn't get called all that often.
 	 */
-	if ((journal->j_fs_dev != journal->j_dev) &&
-	    (journal->j_flags & JBD2_BARRIER))
+	if (journal->j_flags & JBD2_BARRIER)
 		blkdev_issue_flush(journal->j_fs_dev, GFP_KERNEL, NULL);
-	if (!(journal->j_flags & JBD2_ABORT))
-		jbd2_journal_update_sb_log_tail(journal);
+
+	__jbd2_update_log_tail(journal, first_tid, blocknr);
 	return 0;
 }
 

trunk/fs/jbd2/commit.c

@@ -341,7 +341,16 @@ void jbd2_journal_commit_transaction(journal_t *journal)
 	if (journal->j_flags & JBD2_FLUSHED) {
 		jbd_debug(3, "super block updated\n");
 		mutex_lock(&journal->j_checkpoint_mutex);
-		jbd2_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.
+		 */
+		jbd2_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");

trunk/fs/jbd2/journal.c

@@ -742,6 +742,85 @@ struct journal_head *jbd2_journal_get_descriptor_buffer(journal_t *journal)
 	return jbd2_journal_add_journal_head(bh);
 }
 
+/*
+ * Return tid of the oldest transaction in the journal and block in the journal
+ * where the transaction starts.
+ *
+ * If the journal is now empty, return which will be the next transaction ID
+ * we will write and where will that transaction start.
+ *
+ * The return value is 0 if journal tail cannot be pushed any further, 1 if
+ * it can.
+ */
+int jbd2_journal_get_log_tail(journal_t *journal, tid_t *tid,
+			      unsigned long *block)
+{
+	transaction_t *transaction;
+	int ret;
+
+	read_lock(&journal->j_state_lock);
+	spin_lock(&journal->j_list_lock);
+	transaction = journal->j_checkpoint_transactions;
+	if (transaction) {
+		*tid = transaction->t_tid;
+		*block = transaction->t_log_start;
+	} else if ((transaction = journal->j_committing_transaction) != NULL) {
+		*tid = transaction->t_tid;
+		*block = transaction->t_log_start;
+	} else if ((transaction = journal->j_running_transaction) != NULL) {
+		*tid = transaction->t_tid;
+		*block = journal->j_head;
+	} else {
+		*tid = journal->j_transaction_sequence;
+		*block = journal->j_head;
+	}
+	ret = tid_gt(*tid, journal->j_tail_sequence);
+	spin_unlock(&journal->j_list_lock);
+	read_unlock(&journal->j_state_lock);
+
+	return ret;
+}
+
+/*
+ * Update information in journal structure and in on disk journal superblock
+ * about log tail. This function does not check whether information passed in
+ * really pushes log tail further. It's responsibility of the caller to make
+ * sure provided log tail information is valid (e.g. by holding
+ * j_checkpoint_mutex all the time between computing log tail and calling this
+ * function as is the case with jbd2_cleanup_journal_tail()).
+ *
+ * Requires j_checkpoint_mutex
+ */
+void __jbd2_update_log_tail(journal_t *journal, tid_t tid, unsigned long block)
+{
+	unsigned long freed;
+
+	BUG_ON(!mutex_is_locked(&journal->j_checkpoint_mutex));
+
+	/*
+	 * We cannot afford for write to remain in drive's caches since as
+	 * soon as we update j_tail, next transaction can start reusing journal
+	 * space and if we lose sb update during power failure we'd replay
+	 * old transaction with possibly newly overwritten data.
+	 */
+	jbd2_journal_update_sb_log_tail(journal, tid, block, WRITE_FUA);
+	write_lock(&journal->j_state_lock);
+	freed = block - journal->j_tail;
+	if (block < journal->j_tail)
+		freed += journal->j_last - journal->j_first;
+
+	trace_jbd2_update_log_tail(journal, tid, block, freed);
+	jbd_debug(1,
+		  "Cleaning journal tail from %d to %d (offset %lu), "
+		  "freeing %lu\n",
+		  journal->j_tail_sequence, tid, block, freed);
+
+	journal->j_free += freed;
+	journal->j_tail_sequence = tid;
+	journal->j_tail = block;
+	write_unlock(&journal->j_state_lock);
+}
+
 struct jbd2_stats_proc_session {
 	journal_t *journal;
 	struct transaction_stats_s *stats;
@@ -1125,18 +1204,30 @@ 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. */
-		jbd2_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.
+		 */
+		jbd2_journal_update_sb_log_tail(journal,
+						journal->j_tail_sequence,
+						journal->j_tail,
+						WRITE_FUA);
 		mutex_unlock(&journal->j_checkpoint_mutex);
 	}
 	return jbd2_journal_start_thread(journal);
 }
 
-static void jbd2_write_superblock(journal_t *journal)
+static void jbd2_write_superblock(journal_t *journal, int write_op)
 {
 	struct buffer_head *bh = journal->j_sb_buffer;
+	int ret;
 
-	trace_jbd2_write_superblock(journal);
+	trace_jbd2_write_superblock(journal, write_op);
+	if (!(journal->j_flags & JBD2_BARRIER))
+		write_op &= ~(REQ_FUA | REQ_FLUSH);
+	lock_buffer(bh);
 	if (buffer_write_io_error(bh)) {
 		/*
 		 * Oh, dear.  A previous attempt to write the journal
@@ -1152,40 +1243,45 @@ static void jbd2_write_superblock(journal_t *journal)
 		clear_buffer_write_io_error(bh);
 		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)) {
-		printk(KERN_ERR "JBD2: I/O error detected "
-		       "when updating journal superblock for %s.\n",
-		       journal->j_devname);
 		clear_buffer_write_io_error(bh);
 		set_buffer_uptodate(bh);
+		ret = -EIO;
+	}
+	if (ret) {
+		printk(KERN_ERR "JBD2: Error %d detected when updating "
+		       "journal superblock for %s.\n", ret,
+		       journal->j_devname);
 	}
 }
 
 /**
  * jbd2_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 jbd2_journal_update_sb_log_tail(journal_t *journal)
+void jbd2_journal_update_sb_log_tail(journal_t *journal, tid_t tail_tid,
+				     unsigned long tail_block, int write_op)
 {
 	journal_superblock_t *sb = journal->j_superblock;
 
 	BUG_ON(!mutex_is_locked(&journal->j_checkpoint_mutex));
-	read_lock(&journal->j_state_lock);
-	jbd_debug(1, "JBD2: updating superblock (start %ld, seq %d)\n",
-		  journal->j_tail, journal->j_tail_sequence);
+	jbd_debug(1, "JBD2: updating superblock (start %lu, 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);
-	read_unlock(&journal->j_state_lock);
+	sb->s_sequence = cpu_to_be32(tail_tid);
+	sb->s_start    = cpu_to_be32(tail_block);
 
-	jbd2_write_superblock(journal);
+	jbd2_write_superblock(journal, write_op);
 
 	/* Log is no longer empty */
 	write_lock(&journal->j_state_lock);
@@ -1214,7 +1310,7 @@ static void jbd2_mark_journal_empty(journal_t *journal)
 	sb->s_start    = cpu_to_be32(0);
 	read_unlock(&journal->j_state_lock);
 
-	jbd2_write_superblock(journal);
+	jbd2_write_superblock(journal, WRITE_FUA);
 
 	/* Log is no longer empty */
 	write_lock(&journal->j_state_lock);
@@ -1240,7 +1336,7 @@ static void jbd2_journal_update_sb_errno(journal_t *journal)
 	sb->s_errno    = cpu_to_be32(journal->j_errno);
 	read_unlock(&journal->j_state_lock);
 
-	jbd2_write_superblock(journal);
+	jbd2_write_superblock(journal, WRITE_SYNC);
 }
 
 /*

trunk/fs/jbd2/recovery.c

@@ -21,6 +21,7 @@
 #include <linux/jbd2.h>
 #include <linux/errno.h>
 #include <linux/crc32.h>
+#include <linux/blkdev.h>
 #endif
 
 /*
@@ -265,7 +266,9 @@ int jbd2_journal_recover(journal_t *journal)
 	err2 = sync_blockdev(journal->j_fs_dev);
 	if (!err)
 		err = err2;
-
+	/* Make sure all replayed data is on permanent storage */
+	if (journal->j_flags & JBD2_BARRIER)
+		blkdev_issue_flush(journal->j_fs_dev, GFP_KERNEL, NULL);
 	return err;
 }
 

trunk/include/linux/jbd2.h

@@ -971,6 +971,9 @@ extern void __journal_clean_data_list(transaction_t *transaction);
 /* Log buffer allocation */
 extern struct journal_head * jbd2_journal_get_descriptor_buffer(journal_t *);
 int jbd2_journal_next_log_block(journal_t *, unsigned long long *);
+int jbd2_journal_get_log_tail(journal_t *journal, tid_t *tid,
+			      unsigned long *block);
+void __jbd2_update_log_tail(journal_t *journal, tid_t tid, unsigned long block);
 
 /* Commit management */
 extern void jbd2_journal_commit_transaction(journal_t *);
@@ -1087,7 +1090,8 @@ extern int	   jbd2_journal_destroy    (journal_t *);
 extern int	   jbd2_journal_recover    (journal_t *journal);
 extern int	   jbd2_journal_wipe       (journal_t *, int);
 extern int	   jbd2_journal_skip_recovery	(journal_t *);
-extern void	   jbd2_journal_update_sb_log_tail	(journal_t *);
+extern void	   jbd2_journal_update_sb_log_tail	(journal_t *, tid_t,
+				unsigned long, int);
 extern void	   __jbd2_journal_abort_hard	(journal_t *);
 extern void	   jbd2_journal_abort      (journal_t *, int);
 extern int	   jbd2_journal_errno      (journal_t *);

trunk/include/trace/events/jbd2.h

@@ -207,7 +207,7 @@ TRACE_EVENT(jbd2_checkpoint_stats,
 		  __entry->forced_to_close, __entry->written, __entry->dropped)
 );
 
-TRACE_EVENT(jbd2_cleanup_journal_tail,
+TRACE_EVENT(jbd2_update_log_tail,
 
 	TP_PROTO(journal_t *journal, tid_t first_tid,
 		 unsigned long block_nr, unsigned long freed),
@@ -238,19 +238,22 @@ TRACE_EVENT(jbd2_cleanup_journal_tail,
 
 TRACE_EVENT(jbd2_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_JBD2_H */