[PATCH] Allow file systems to differentiate between data and meta reads

We can use this information for making more intelligent priority
decisions, and it will also be useful for blktrace.

Signed-off-by: Jens Axboe <axboe@suse.de>

4 files changed, 8 insertions, 0 deletions

diff --git a/block/ll_rw_blk.c b/block/ll_rw_blk.c
index e3980ec747c1..57992ae511c2 100644
--- a/block/ll_rw_blk.c
+++ b/block/ll_rw_blk.c
@@ -2884,6 +2884,8 @@ static void init_request_from_bio(struct request *req, struct bio *bio)
 
         if (bio_sync(bio))
                 req->cmd_flags |= REQ_RW_SYNC;
+        if (bio_rw_meta(bio))
+                req->cmd_flags |= REQ_RW_META;
 
         req->errors = 0;
         req->hard_sector = req->sector = bio->bi_sector;
diff --git a/include/linux/bio.h b/include/linux/bio.h
index 76bdaeab6f62..711c321a7011 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -148,6 +148,7 @@ struct bio {
 #define BIO_RW_BARRIER  2
 #define BIO_RW_FAILFAST 3
 #define BIO_RW_SYNC     4
+#define BIO_RW_META     5
 
 /*
  * upper 16 bits of bi_rw define the io priority of this bio
@@ -178,6 +179,7 @@ struct bio {
 #define bio_sync(bio)           ((bio)->bi_rw & (1 << BIO_RW_SYNC))
 #define bio_failfast(bio)       ((bio)->bi_rw & (1 << BIO_RW_FAILFAST))
 #define bio_rw_ahead(bio)       ((bio)->bi_rw & (1 << BIO_RW_AHEAD))
+#define bio_rw_meta(bio)        ((bio)->bi_rw & (1 << BIO_RW_META))
 
 /*
  * will die
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 5d8e288db163..2c01a90998a7 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -180,6 +180,7 @@ enum rq_flag_bits {
         __REQ_ORDERED_COLOR,    /* is before or after barrier */
         __REQ_RW_SYNC,          /* request is sync (O_DIRECT) */
         __REQ_ALLOCED,          /* request came from our alloc pool */
+        __REQ_RW_META,          /* metadata io request */
         __REQ_NR_BITS,          /* stops here */
 };
 
@@ -200,6 +201,7 @@ enum rq_flag_bits {
 #define REQ_ORDERED_COLOR       (1 << __REQ_ORDERED_COLOR)
 #define REQ_RW_SYNC     (1 << __REQ_RW_SYNC)
 #define REQ_ALLOCED     (1 << __REQ_ALLOCED)
+#define REQ_RW_META     (1 << __REQ_RW_META)
 
 #define BLK_MAX_CDB     16
 
@@ -543,6 +545,7 @@ enum {
  * We regard a request as sync, if it's a READ or a SYNC write.
  */
 #define rq_is_sync(rq)          (rq_data_dir((rq)) == READ || (rq)->cmd_flags & REQ_RW_SYNC)
+#define rq_is_meta(rq)          ((rq)->cmd_flags & REQ_RW_META)
 
 static inline int blk_queue_full(struct request_queue *q, int rw)
 {
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 9306f63bf77e..d68c37af4dfb 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -80,6 +80,7 @@ extern int dir_notify_enable;
 #define READA 2         /* read-ahead  - don't block if no resources */
 #define SWRITE 3        /* for ll_rw_block() - wait for buffer lock */
 #define READ_SYNC       (READ | (1 << BIO_RW_SYNC))
+#define READ_META       (READ | (1 << BIO_RW_META))
 #define WRITE_SYNC      (WRITE | (1 << BIO_RW_SYNC))
 #define WRITE_BARRIER   ((1 << BIO_RW) | (1 << BIO_RW_BARRIER))