block: separate priority boosting from REQ_META

Add a new REQ_PRIO to let requests preempt others in the cfq I/O schedule,
and lave REQ_META purely for marking requests as metadata in blktrace.

All existing callers of REQ_META except for XFS are updated to also
set REQ_PRIO for now.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Namhyung Kim <namhyung@gmail.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

8 files changed, 15 insertions, 13 deletions

diff --git a/fs/ext3/inode.c b/fs/ext3/inode.c
index bba7b96e0d9b..12661e1deedd 100644
--- a/fs/ext3/inode.c
+++ b/fs/ext3/inode.c
@@ -1134,7 +1134,7 @@ struct buffer_head *ext3_bread(handle_t *handle, struct inode *inode,
                 return bh;
         if (buffer_uptodate(bh))
                 return bh;
-        ll_rw_block(READ | REQ_META, 1, &bh);
+        ll_rw_block(READ | REQ_META | REQ_PRIO, 1, &bh);
         wait_on_buffer(bh);
         if (buffer_uptodate(bh))
                 return bh;
@@ -2807,7 +2807,7 @@ make_io:
                 trace_ext3_load_inode(inode);
                 get_bh(bh);
                 bh->b_end_io = end_buffer_read_sync;
-                submit_bh(READ | REQ_META, bh);
+                submit_bh(READ | REQ_META | REQ_PRIO, bh);
                 wait_on_buffer(bh);
                 if (!buffer_uptodate(bh)) {
                         ext3_error(inode->i_sb, "ext3_get_inode_loc",
diff --git a/fs/ext3/namei.c b/fs/ext3/namei.c
index c7d4032aa82a..0629e09f6511 100644
--- a/fs/ext3/namei.c
+++ b/fs/ext3/namei.c
@@ -922,7 +922,8 @@ restart:
                                 bh = ext3_getblk(NULL, dir, b++, 0, &err);
                                 bh_use[ra_max] = bh;
                                 if (bh)
-                                        ll_rw_block(READ | REQ_META, 1, &bh);
+                                        ll_rw_block(READ | REQ_META | REQ_PRIO,
+                                                    1, &bh);
                         }
                 }
                 if ((bh = bh_use[ra_ptr++]) == NULL)
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 1dfa18feeb3e..c7cbb3d85d9e 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -650,7 +650,7 @@ struct buffer_head *ext4_bread(handle_t *handle, struct inode *inode,
                 return bh;
         if (buffer_uptodate(bh))
                 return bh;
-        ll_rw_block(READ | REQ_META, 1, &bh);
+        ll_rw_block(READ | REQ_META | REQ_PRIO, 1, &bh);
         wait_on_buffer(bh);
         if (buffer_uptodate(bh))
                 return bh;
@@ -3301,7 +3301,7 @@ make_io:
                 trace_ext4_load_inode(inode);
                 get_bh(bh);
                 bh->b_end_io = end_buffer_read_sync;
-                submit_bh(READ | REQ_META, bh);
+                submit_bh(READ | REQ_META | REQ_PRIO, bh);
                 wait_on_buffer(bh);
                 if (!buffer_uptodate(bh)) {
                         EXT4_ERROR_INODE_BLOCK(inode, block,
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index d36315ae629e..1c924faeb6c8 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -922,7 +922,8 @@ restart:
                                 bh = ext4_getblk(NULL, dir, b++, 0, &err);
                                 bh_use[ra_max] = bh;
                                 if (bh)
-                                        ll_rw_block(READ | REQ_META, 1, &bh);
+                                        ll_rw_block(READ | REQ_META | REQ_PRIO,
+                                                    1, &bh);
                         }
                 }
                 if ((bh = bh_use[ra_ptr++]) == NULL)
diff --git a/fs/gfs2/log.c b/fs/gfs2/log.c
index 85c62923ee29..598646434362 100644
--- a/fs/gfs2/log.c
+++ b/fs/gfs2/log.c
@@ -624,9 +624,9 @@ static void log_write_header(struct gfs2_sbd *sdp, u32 flags, int pull)
         bh->b_end_io = end_buffer_write_sync;
         get_bh(bh);
         if (test_bit(SDF_NOBARRIERS, &sdp->sd_flags))
-                submit_bh(WRITE_SYNC | REQ_META, bh);
+                submit_bh(WRITE_SYNC | REQ_META | REQ_PRIO, bh);
         else
-                submit_bh(WRITE_FLUSH_FUA | REQ_META, bh);
+                submit_bh(WRITE_FLUSH_FUA | REQ_META | REQ_PRIO, bh);
         wait_on_buffer(bh);
 
         if (!buffer_uptodate(bh))
diff --git a/fs/gfs2/meta_io.c b/fs/gfs2/meta_io.c
index 747238cd9f96..be29858900f6 100644
--- a/fs/gfs2/meta_io.c
+++ b/fs/gfs2/meta_io.c
@@ -37,7 +37,7 @@ static int gfs2_aspace_writepage(struct page *page, struct writeback_control *wb
 {
         struct buffer_head *bh, *head;
         int nr_underway = 0;
-        int write_op = REQ_META |
+        int write_op = REQ_META | REQ_PRIO |
                 (wbc->sync_mode == WB_SYNC_ALL ? WRITE_SYNC : WRITE);
 
         BUG_ON(!PageLocked(page));
@@ -225,7 +225,7 @@ int gfs2_meta_read(struct gfs2_glock *gl, u64 blkno, int flags,
         }
         bh->b_end_io = end_buffer_read_sync;
         get_bh(bh);
-        submit_bh(READ_SYNC | REQ_META, bh);
+        submit_bh(READ_SYNC | REQ_META | REQ_PRIO, bh);
         if (!(flags & DIO_WAIT))
                 return 0;
 
@@ -435,7 +435,7 @@ struct buffer_head *gfs2_meta_ra(struct gfs2_glock *gl, u64 dblock, u32 extlen)
         if (buffer_uptodate(first_bh))
                 goto out;
         if (!buffer_locked(first_bh))
-                ll_rw_block(READ_SYNC | REQ_META, 1, &first_bh);
+                ll_rw_block(READ_SYNC | REQ_META | REQ_PRIO, 1, &first_bh);
 
         dblock++;
         extlen--;
diff --git a/fs/gfs2/ops_fstype.c b/fs/gfs2/ops_fstype.c
index 3bc073a4cf82..079587e53849 100644
--- a/fs/gfs2/ops_fstype.c
+++ b/fs/gfs2/ops_fstype.c
@@ -224,7 +224,7 @@ static int gfs2_read_super(struct gfs2_sbd *sdp, sector_t sector, int silent)
 
         bio->bi_end_io = end_bio_io_page;
         bio->bi_private = page;
-        submit_bio(READ_SYNC | REQ_META, bio);
+        submit_bio(READ_SYNC | REQ_META | REQ_PRIO, bio);
         wait_on_page_locked(page);
         bio_put(bio);
         if (!PageUptodate(page)) {
diff --git a/fs/gfs2/quota.c b/fs/gfs2/quota.c
index 053434049dbb..0e8bb13381e4 100644
--- a/fs/gfs2/quota.c
+++ b/fs/gfs2/quota.c
@@ -709,7 +709,7 @@ get_a_page:
                 set_buffer_uptodate(bh);
 
         if (!buffer_uptodate(bh)) {
-                ll_rw_block(READ | REQ_META, 1, &bh);
+                ll_rw_block(READ | REQ_META | REQ_PRIO, 1, &bh);
                 wait_on_buffer(bh);
                 if (!buffer_uptodate(bh))
                         goto unlock_out;