raid5: support sync request

REQ_SYNC is ignored in current raid5 code. Block layer does use it to do
policy,
for example ioscheduler. This patch adds it.

Signed-off-by: Shaohua Li <shli@fusionio.com>
Signed-off-by: NeilBrown <neilb@suse.de>

2 files changed, 11 insertions, 2 deletions

diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 962c8f40908f..7bfd59b313d7 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -539,6 +539,8 @@ static void ops_run_io(struct stripe_head *sh, struct stripe_head_state *s)
                         replace_only = 1;
                 } else
                         continue;
+                if (test_and_clear_bit(R5_SyncIO, &sh->dev[i].flags))
+                        rw |= REQ_SYNC;
 
                 bi = &sh->dev[i].req;
                 rbi = &sh->dev[i].rreq; /* For writing to replacement */
@@ -1145,6 +1147,8 @@ ops_run_biodrain(struct stripe_head *sh, struct dma_async_tx_descriptor *tx)
                                 dev->sector + STRIPE_SECTORS) {
                                 if (wbi->bi_rw & REQ_FUA)
                                         set_bit(R5_WantFUA, &dev->flags);
+                                if (wbi->bi_rw & REQ_SYNC)
+                                        set_bit(R5_SyncIO, &dev->flags);
                                 tx = async_copy_data(1, wbi, dev->page,
                                         dev->sector, tx);
                                 wbi = r5_next_bio(wbi, dev->sector);
@@ -1162,13 +1166,15 @@ static void ops_complete_reconstruct(void *stripe_head_ref)
         int pd_idx = sh->pd_idx;
         int qd_idx = sh->qd_idx;
         int i;
-        bool fua = false;
+        bool fua = false, sync = false;
 
         pr_debug("%s: stripe %llu\n", __func__,
                 (unsigned long long)sh->sector);
 
-        for (i = disks; i--; )
+        for (i = disks; i--; ) {
                 fua |= test_bit(R5_WantFUA, &sh->dev[i].flags);
+                sync |= test_bit(R5_SyncIO, &sh->dev[i].flags);
+        }
 
         for (i = disks; i--; ) {
                 struct r5dev *dev = &sh->dev[i];
@@ -1177,6 +1183,8 @@ static void ops_complete_reconstruct(void *stripe_head_ref)
                         set_bit(R5_UPTODATE, &dev->flags);
                         if (fua)
                                 set_bit(R5_WantFUA, &dev->flags);
+                        if (sync)
+                                set_bit(R5_SyncIO, &dev->flags);
                 }
         }
 
diff --git a/drivers/md/raid5.h b/drivers/md/raid5.h
index c6bdfa01d987..2164021f3b5f 100644
--- a/drivers/md/raid5.h
+++ b/drivers/md/raid5.h
@@ -285,6 +285,7 @@ enum r5dev_flags {
                          */
         R5_Wantdrain,   /* dev->towrite needs to be drained */
         R5_WantFUA,     /* Write should be FUA */
+        R5_SyncIO,      /* The IO is sync */
         R5_WriteError,  /* got a write error - need to record it */
         R5_MadeGood,    /* A bad block has been fixed by writing to it */
         R5_ReadRepl,    /* Will/did read from replacement rather than orig */