buffer: add BH_Prio and BH_Meta flags

Add buffer_head flags so that buffer cache writebacks can be marked
with the the appropriate request flags, so that metadata blocks can be
marked appropriately in blktrace.

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

1 files changed, 5 insertions, 0 deletions

diff --git a/fs/buffer.c b/fs/buffer.c
index b4dcb34c9635..a15575c0b9ee 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -2988,6 +2988,11 @@ int submit_bh(int rw, struct buffer_head * bh)
         /* Take care of bh's that straddle the end of the device */
         guard_bh_eod(rw, bio, bh);
 
+        if (buffer_meta(bh))
+                rw |= REQ_META;
+        if (buffer_prio(bh))
+                rw |= REQ_PRIO;
+
         bio_get(bio);
         submit_bio(rw, bio);