[PATCH] ext3 barrier support

Mount with "mount -o barrier=1" to enable barriers.
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

fs/ext3/super.c

@@ -587,7 +587,7 @@ enum {
 	Opt_abort, Opt_data_journal, Opt_data_ordered, Opt_data_writeback,
 	Opt_usrjquota, Opt_grpjquota, Opt_offusrjquota, Opt_offgrpjquota,
 	Opt_jqfmt_vfsold, Opt_jqfmt_vfsv0,
-	Opt_ignore, Opt_err,
+	Opt_ignore, Opt_barrier, Opt_err,
 };
 
 static match_table_t tokens = {
@@ -632,6 +632,7 @@ static match_table_t tokens = {
 	{Opt_ignore, "noquota"},
 	{Opt_ignore, "quota"},
 	{Opt_ignore, "usrquota"},
+	{Opt_barrier, "barrier=%u"},
 	{Opt_err, NULL}
 };
 
@@ -897,6 +898,14 @@ static int parse_options (char * options, struct super_block *sb,
 		case Opt_abort:
 			set_opt(sbi->s_mount_opt, ABORT);
 			break;
+		case Opt_barrier:
+			if (match_int(&args[0], &option))
+				return 0;
+			if (option)
+				set_opt(sbi->s_mount_opt, BARRIER);
+			else
+				clear_opt(sbi->s_mount_opt, BARRIER);
+			break;
 		case Opt_ignore:
 			break;
 		default:
@@ -1599,16 +1608,23 @@ static int ext3_fill_super (struct super_block *sb, void *data, int silent)
  * initial mount, once the journal has been initialised but before we've
  * done any recovery; and again on any subsequent remount. 
  */
-static void ext3_init_journal_params(struct ext3_sb_info *sbi, 
-				     journal_t *journal)
+static void ext3_init_journal_params(struct super_block *sb, journal_t *journal)
 {
+	struct ext3_sb_info *sbi = EXT3_SB(sb);
+
 	if (sbi->s_commit_interval)
 		journal->j_commit_interval = sbi->s_commit_interval;
 	/* We could also set up an ext3-specific default for the commit
 	 * interval here, but for now we'll just fall back to the jbd
 	 * default. */
-}
 
+	spin_lock(&journal->j_state_lock);
+	if (test_opt(sb, BARRIER))
+		journal->j_flags |= JFS_BARRIER;
+	else
+		journal->j_flags &= ~JFS_BARRIER;
+	spin_unlock(&journal->j_state_lock);
+}
 
 static journal_t *ext3_get_journal(struct super_block *sb, int journal_inum)
 {
@@ -1646,7 +1662,7 @@ static journal_t *ext3_get_journal(struct super_block *sb, int journal_inum)
 		return NULL;
 	}
 	journal->j_private = sb;
-	ext3_init_journal_params(EXT3_SB(sb), journal);
+	ext3_init_journal_params(sb, journal);
 	return journal;
 }
 
@@ -1731,7 +1747,7 @@ static journal_t *ext3_get_dev_journal(struct super_block *sb,
 		goto out_journal;
 	}
 	EXT3_SB(sb)->journal_bdev = bdev;
-	ext3_init_journal_params(EXT3_SB(sb), journal);
+	ext3_init_journal_params(sb, journal);
 	return journal;
 out_journal:
 	journal_destroy(journal);
@@ -2028,7 +2044,7 @@ int ext3_remount (struct super_block * sb, int * flags, char * data)
 
 	es = sbi->s_es;
 
-	ext3_init_journal_params(sbi, sbi->s_journal);
+	ext3_init_journal_params(sb, sbi->s_journal);
 
 	if ((*flags & MS_RDONLY) != (sb->s_flags & MS_RDONLY)) {
 		if (sbi->s_mount_opt & EXT3_MOUNT_ABORT)

fs/jbd/commit.c

@@ -639,10 +639,38 @@ void journal_commit_transaction(journal_t *journal)
 	JBUFFER_TRACE(descriptor, "write commit block");
 	{
 		struct buffer_head *bh = jh2bh(descriptor);
+		int ret;
+		int barrier_done = 0;
 
 		set_buffer_dirty(bh);
-		sync_dirty_buffer(bh);
-		if (unlikely(!buffer_uptodate(bh)))
+		if (journal->j_flags & JFS_BARRIER) {
+			set_buffer_ordered(bh);
+			barrier_done = 1;
+		}
+		ret = sync_dirty_buffer(bh);
+		/* is it possible for another commit to fail at roughly
+		 * the same time as this one?  If so, we don't want to
+		 * trust the barrier flag in the super, but instead want
+		 * to remember if we sent a barrier request
+		 */
+		if (ret == -EOPNOTSUPP && barrier_done) {
+			char b[BDEVNAME_SIZE];
+
+			printk(KERN_WARNING
+				"JBD: barrier-based sync failed on %s - "
+				"disabling barriers\n",
+				bdevname(journal->j_dev, b));
+			spin_lock(&journal->j_state_lock);
+			journal->j_flags &= ~JFS_BARRIER;
+			spin_unlock(&journal->j_state_lock);
+
+			/* And try again, without the barrier */
+			clear_buffer_ordered(bh);
+			set_buffer_uptodate(bh);
+			set_buffer_dirty(bh);
+			ret = sync_dirty_buffer(bh);
+		}
+		if (unlikely(ret == -EIO))
 			err = -EIO;
 		put_bh(bh);		/* One for getblk() */
 		journal_put_journal_head(descriptor);

fs/reiserfs/journal.c

@@ -655,6 +655,17 @@ static int submit_barrier_buffer(struct buffer_head *bh) {
     return submit_bh(WRITE_BARRIER, bh) ;
 }
 
+static void check_barrier_completion(struct super_block *s,
+                                     struct buffer_head *bh) {
+    if (buffer_eopnotsupp(bh)) {
+	clear_buffer_eopnotsupp(bh);
+	disable_barrier(s);
+	set_buffer_uptodate(bh);
+	set_buffer_dirty(bh);
+	sync_dirty_buffer(bh);
+    }
+}
+
 #define CHUNK_SIZE 32
 struct buffer_chunk {
     struct buffer_head *bh[CHUNK_SIZE];
@@ -1032,6 +1043,7 @@ static int flush_commit_list(struct super_block *s, struct reiserfs_journal_list
   } else
       wait_on_buffer(jl->j_commit_bh);
 
+  check_barrier_completion(s, jl->j_commit_bh);
   if (!buffer_uptodate(jl->j_commit_bh)) {
     reiserfs_panic(s, "journal-615: buffer write failed\n") ;
   }
@@ -1142,6 +1154,7 @@ static int _update_journal_header_block(struct super_block *p_s_sb, unsigned lon
 	    goto sync;
 	}
 	wait_on_buffer(SB_JOURNAL(p_s_sb)->j_header_bh);
+	check_barrier_completion(p_s_sb, SB_JOURNAL(p_s_sb)->j_header_bh);
     } else {
 sync:
 	set_buffer_dirty(SB_JOURNAL(p_s_sb)->j_header_bh) ;

include/linux/ext3_fs.h

@@ -324,6 +324,7 @@ struct ext3_inode {
 #define EXT3_MOUNT_NO_UID32		0x2000  /* Disable 32-bit UIDs */
 #define EXT3_MOUNT_XATTR_USER		0x4000	/* Extended user attributes */
 #define EXT3_MOUNT_POSIX_ACL		0x8000	/* POSIX Access Control Lists */
+#define EXT3_MOUNT_BARRIER		0x10000 /* Use block barriers */
 
 /* Compatibility, for having both ext2_fs.h and ext3_fs.h included at once */
 #ifndef _LINUX_EXT2_FS_H

include/linux/jbd.h

@@ -840,6 +840,7 @@ struct journal_s
 #define JFS_ACK_ERR	0x004	/* The errno in the sb has been acked */
 #define JFS_FLUSHED	0x008	/* The journal superblock has been flushed */
 #define JFS_LOADED	0x010	/* The journal superblock has been loaded */
+#define JFS_BARRIER	0x020	/* Use IDE barriers */
 
 /* 
  * Function declarations for the journaling transaction and buffer