From: Theodore Ts'o <tytso@mit.edu>
Date: Sat, 20 Apr 2013 19:46:17 +0000 (-0400)
Subject: ext4: mark all metadata I/O with REQ_META
X-Git-Tag: v3.10-rc1~138^2~7
X-Git-Url: http://pileus.org/git/?a=commitdiff_plain;h=9f203507ed277ee86e3f76a15e09db1c92e40b94;hp=c4d8b0235aa98f8c26bf94d308be3fdd24154572;p=~andy%2Flinux

ext4: mark all metadata I/O with REQ_META

As Dave Chinner pointed out at the 2013 LSF/MM workshop, it's
important that metadata I/O requests are marked as such to avoid
priority inversions caused by I/O bandwidth throttling.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
---

diff --git a/fs/ext4/balloc.c b/fs/ext4/balloc.c
index 8dcaea69e37..d0f13eada0e 100644
--- a/fs/ext4/balloc.c
+++ b/fs/ext4/balloc.c
@@ -441,7 +441,7 @@ ext4_read_block_bitmap_nowait(struct super_block *sb, ext4_group_t block_group)
 	trace_ext4_read_block_bitmap_load(sb, block_group);
 	bh->b_end_io = ext4_end_bitmap_read;
 	get_bh(bh);
-	submit_bh(READ, bh);
+	submit_bh(READ | REQ_META | REQ_PRIO, bh);
 	return bh;
 verify:
 	ext4_validate_block_bitmap(sb, desc, block_group, bh);
diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
index 18d36d85f5c..00a818d67b5 100644
--- a/fs/ext4/ialloc.c
+++ b/fs/ext4/ialloc.c
@@ -166,7 +166,7 @@ ext4_read_inode_bitmap(struct super_block *sb, ext4_group_t block_group)
 	trace_ext4_load_inode_bitmap(sb, block_group);
 	bh->b_end_io = ext4_end_bitmap_read;
 	get_bh(bh);
-	submit_bh(READ, bh);
+	submit_bh(READ | REQ_META | REQ_PRIO, bh);
 	wait_on_buffer(bh);
 	if (!buffer_uptodate(bh)) {
 		put_bh(bh);
diff --git a/fs/ext4/mmp.c b/fs/ext4/mmp.c
index b3b1f7d9944..214461e42a0 100644
--- a/fs/ext4/mmp.c
+++ b/fs/ext4/mmp.c
@@ -54,7 +54,7 @@ static int write_mmp_block(struct super_block *sb, struct buffer_head *bh)
 	lock_buffer(bh);
 	bh->b_end_io = end_buffer_write_sync;
 	get_bh(bh);
-	submit_bh(WRITE_SYNC, bh);
+	submit_bh(WRITE_SYNC | REQ_META | REQ_PRIO, bh);
 	wait_on_buffer(bh);
 	sb_end_write(sb);
 	if (unlikely(!buffer_uptodate(bh)))
@@ -86,7 +86,7 @@ static int read_mmp_block(struct super_block *sb, struct buffer_head **bh,
 		get_bh(*bh);
 		lock_buffer(*bh);
 		(*bh)->b_end_io = end_buffer_read_sync;
-		submit_bh(READ_SYNC, *bh);
+		submit_bh(READ_SYNC | REQ_META | REQ_PRIO, *bh);
 		wait_on_buffer(*bh);
 		if (!buffer_uptodate(*bh)) {
 			brelse(*bh);
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index bfa29ecfb47..dbc7c090c13 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -4252,7 +4252,7 @@ static journal_t *ext4_get_dev_journal(struct super_block *sb,
 		goto out_bdev;
 	}
 	journal->j_private = sb;
-	ll_rw_block(READ, 1, &journal->j_sb_buffer);
+	ll_rw_block(READ | REQ_META | REQ_PRIO, 1, &journal->j_sb_buffer);
 	wait_on_buffer(journal->j_sb_buffer);
 	if (!buffer_uptodate(journal->j_sb_buffer)) {
 		ext4_msg(sb, KERN_ERR, "I/O error on journal device");