md/raid5: fix FUA request handling in ops_run_io()

Commit e9c7469bb4f5 ("md: implment REQ_FLUSH/FUA support")
introduced R5_WantFUA flag and set rw to WRITE_FUA in that case.
However remaining code still checks whether rw is exactly same
as WRITE or not, so FUAed-write ends up with being treated as
READ. Fix it.

This bug has been present since 2.6.37 and the fix is suitable for any
-stable kernel since then.  It is not clear why this has not caused
more problems.

Cc: Tejun Heo <tj@kernel.org>
Cc: stable@kernel.org
Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Signed-off-by: NeilBrown <neilb@suse.de>

diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index af8a9a8..b7dcc67 100644 (file)
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -514,7 +514,7 @@ static void ops_run_io(struct stripe_head *sh, struct stripe_head_state *s)
                bi = &sh->dev[i].req;
 
                bi->bi_rw = rw;
-               if (rw == WRITE)
+               if (rw & WRITE)
                        bi->bi_end_io = raid5_end_write_request;
                else
                        bi->bi_end_io = raid5_end_read_request;
@@ -548,13 +548,13 @@ static void ops_run_io(struct stripe_head *sh, struct stripe_head_state *s)
                        bi->bi_io_vec[0].bv_offset = 0;
                        bi->bi_size = STRIPE_SIZE;
                        bi->bi_next = NULL;
-                       if (rw == WRITE &&
+                       if ((rw & WRITE) &&
                            test_bit(R5_ReWrite, &sh->dev[i].flags))
                                atomic_add(STRIPE_SECTORS,
                                        &rdev->corrected_errors);
                        generic_make_request(bi);
                } else {
-                       if (rw == WRITE)
+                       if (rw & WRITE)
                                set_bit(STRIPE_DEGRADED, &sh->state);
                        pr_debug("skip op %ld on disc %d for sector %llu\n",
                                bi->bi_rw, i, (unsigned long long)sh->sector);