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>

4 files changed, 5 insertions, 5 deletions

diff --git a/fs/ext4/balloc.c b/fs/ext4/balloc.c
index 8dcaea69e37f..d0f13eada0ed 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 18d36d85f5c9..00a818d67b54 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 b3b1f7d99448..214461e42a05 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 bfa29ecfb47a..dbc7c090c13a 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");