kill BH_Ordered flag

Instead of abusing a buffer_head flag just add a variant of
sync_dirty_buffer which allows passing the exact type of write
flag required.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/buffer.c

@@ -2911,13 +2911,6 @@ int submit_bh(int rw, struct buffer_head * bh)
 	BUG_ON(buffer_delay(bh));
 	BUG_ON(buffer_unwritten(bh));
 
-	/*
-	 * Mask in barrier bit for a write (could be either a WRITE or a
-	 * WRITE_SYNC
-	 */
-	if (buffer_ordered(bh) && (rw & WRITE))
-		rw |= WRITE_BARRIER;
-
 	/*
 	 * Only clear out a write error when rewriting
 	 */
@@ -3021,7 +3014,7 @@ EXPORT_SYMBOL(ll_rw_block);
  * and then start new I/O and then wait upon it.  The caller must have a ref on
  * the buffer_head.
  */
-int sync_dirty_buffer(struct buffer_head *bh)
+int __sync_dirty_buffer(struct buffer_head *bh, int rw)
 {
 	int ret = 0;
 
@@ -3030,7 +3023,7 @@ int sync_dirty_buffer(struct buffer_head *bh)
 	if (test_clear_buffer_dirty(bh)) {
 		get_bh(bh);
 		bh->b_end_io = end_buffer_write_sync;
-		ret = submit_bh(WRITE_SYNC, bh);
+		ret = submit_bh(rw, bh);
 		wait_on_buffer(bh);
 		if (buffer_eopnotsupp(bh)) {
 			clear_buffer_eopnotsupp(bh);
@@ -3043,6 +3036,12 @@ int sync_dirty_buffer(struct buffer_head *bh)
 	}
 	return ret;
 }
+EXPORT_SYMBOL(__sync_dirty_buffer);
+
+int sync_dirty_buffer(struct buffer_head *bh)
+{
+	return __sync_dirty_buffer(bh, WRITE_SYNC);
+}
 EXPORT_SYMBOL(sync_dirty_buffer);
 
 /*

fs/jbd/commit.c

@@ -119,7 +119,6 @@ static int journal_write_commit_record(journal_t *journal,
 	struct buffer_head *bh;
 	journal_header_t *header;
 	int ret;
-	int barrier_done = 0;
 
 	if (is_journal_aborted(journal))
 		return 0;
@@ -137,34 +136,36 @@ static int journal_write_commit_record(journal_t *journal,
 
 	JBUFFER_TRACE(descriptor, "write commit block");
 	set_buffer_dirty(bh);
+
 	if (journal->j_flags & JFS_BARRIER) {
-		set_buffer_ordered(bh);
-		barrier_done = 1;
-	}
-	ret = sync_dirty_buffer(bh);
-	if (barrier_done)
-		clear_buffer_ordered(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];
+		ret = __sync_dirty_buffer(bh, WRITE_SYNC | WRITE_BARRIER);
 
-		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);
+		/*
+		 * 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) {
+			char b[BDEVNAME_SIZE];
 
-		/* And try again, without the barrier */
-		set_buffer_uptodate(bh);
-		set_buffer_dirty(bh);
+			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 */
+			set_buffer_uptodate(bh);
+			set_buffer_dirty(bh);
+			ret = sync_dirty_buffer(bh);
+		}
+	} else {
 		ret = sync_dirty_buffer(bh);
 	}
+
 	put_bh(bh);		/* One for getblk() */
 	journal_put_journal_head(descriptor);
 

fs/jbd2/commit.c

@@ -101,7 +101,6 @@ static int journal_submit_commit_record(journal_t *journal,
 	struct commit_header *tmp;
 	struct buffer_head *bh;
 	int ret;
-	int barrier_done = 0;
 	struct timespec now = current_kernel_time();
 
 	if (is_journal_aborted(journal))
@@ -136,30 +135,22 @@ static int journal_submit_commit_record(journal_t *journal,
 	if (journal->j_flags & JBD2_BARRIER &&
 	    !JBD2_HAS_INCOMPAT_FEATURE(journal,
 				       JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT)) {
-		set_buffer_ordered(bh);
-		barrier_done = 1;
-	}
-	ret = submit_bh(WRITE_SYNC_PLUG, bh);
-	if (barrier_done)
-		clear_buffer_ordered(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) {
-		printk(KERN_WARNING
-		       "JBD2: Disabling barriers on %s, "
-		       "not supported by device\n", journal->j_devname);
-		write_lock(&journal->j_state_lock);
-		journal->j_flags &= ~JBD2_BARRIER;
-		write_unlock(&journal->j_state_lock);
+		ret = submit_bh(WRITE_SYNC_PLUG | WRITE_BARRIER, bh);
+		if (ret == -EOPNOTSUPP) {
+			printk(KERN_WARNING
+			       "JBD2: Disabling barriers on %s, "
+			       "not supported by device\n", journal->j_devname);
+			write_lock(&journal->j_state_lock);
+			journal->j_flags &= ~JBD2_BARRIER;
+			write_unlock(&journal->j_state_lock);
 
-		/* And try again, without the barrier */
-		lock_buffer(bh);
-		set_buffer_uptodate(bh);
-		clear_buffer_dirty(bh);
+			/* And try again, without the barrier */
+			lock_buffer(bh);
+			set_buffer_uptodate(bh);
+			clear_buffer_dirty(bh);
+			ret = submit_bh(WRITE_SYNC_PLUG, bh);
+		}
+	} else {
 		ret = submit_bh(WRITE_SYNC_PLUG, bh);
 	}
 	*cbh = bh;

fs/nilfs2/super.c

@@ -175,24 +175,24 @@ static int nilfs_sync_super(struct nilfs_sb_info *sbi, int flag)
 {
 	struct the_nilfs *nilfs = sbi->s_nilfs;
 	int err;
-	int barrier_done = 0;
 
-	if (nilfs_test_opt(sbi, BARRIER)) {
-		set_buffer_ordered(nilfs->ns_sbh[0]);
-		barrier_done = 1;
-	}
  retry:
 	set_buffer_dirty(nilfs->ns_sbh[0]);
-	err = sync_dirty_buffer(nilfs->ns_sbh[0]);
-	if (err == -EOPNOTSUPP && barrier_done) {
-		nilfs_warning(sbi->s_super, __func__,
-			      "barrier-based sync failed. "
-			      "disabling barriers\n");
-		nilfs_clear_opt(sbi, BARRIER);
-		barrier_done = 0;
-		clear_buffer_ordered(nilfs->ns_sbh[0]);
-		goto retry;
+
+	if (nilfs_test_opt(sbi, BARRIER)) {
+		err = __sync_dirty_buffer(nilfs->ns_sbh[0],
+					  WRITE_SYNC | WRITE_BARRIER);
+		if (err == -EOPNOTSUPP) {
+			nilfs_warning(sbi->s_super, __func__,
+				      "barrier-based sync failed. "
+				      "disabling barriers\n");
+			nilfs_clear_opt(sbi, BARRIER);
+			goto retry;
+		}
+	} else {
+		err = sync_dirty_buffer(nilfs->ns_sbh[0]);
 	}
+
 	if (unlikely(err)) {
 		printk(KERN_ERR
 		       "NILFS: unable to write superblock (err=%d)\n", err);

include/linux/buffer_head.h

@@ -32,7 +32,6 @@ enum bh_state_bits {
 	BH_Delay,	/* Buffer is not yet allocated on disk */
 	BH_Boundary,	/* Block is followed by a discontiguity */
 	BH_Write_EIO,	/* I/O error on write */
-	BH_Ordered,	/* ordered write */
 	BH_Eopnotsupp,	/* operation not supported (barrier) */
 	BH_Unwritten,	/* Buffer is allocated on disk but not written */
 	BH_Quiet,	/* Buffer Error Prinks to be quiet */
@@ -125,7 +124,6 @@ BUFFER_FNS(Async_Write, async_write)
 BUFFER_FNS(Delay, delay)
 BUFFER_FNS(Boundary, boundary)
 BUFFER_FNS(Write_EIO, write_io_error)
-BUFFER_FNS(Ordered, ordered)
 BUFFER_FNS(Eopnotsupp, eopnotsupp)
 BUFFER_FNS(Unwritten, unwritten)
 
@@ -183,6 +181,7 @@ void unlock_buffer(struct buffer_head *bh);
 void __lock_buffer(struct buffer_head *bh);
 void ll_rw_block(int, int, struct buffer_head * bh[]);
 int sync_dirty_buffer(struct buffer_head *bh);
+int __sync_dirty_buffer(struct buffer_head *bh, int rw);
 int submit_bh(int, struct buffer_head *);
 void write_boundary_block(struct block_device *bdev,
 			sector_t bblock, unsigned blocksize);