dm flakey: fix reads to be issued if drop_writes configured

v4.8-rc3 commit 99f3c90d0d ("dm flakey: error READ bios during the
down_interval") overlooked the 'drop_writes' feature, which is meant to
allow reads to be issued rather than errored, during the down_interval.

Fixes: 99f3c90d0d ("dm flakey: error READ bios during the down_interval")
Reported-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org

diff --git a/drivers/md/dm-flakey.c b/drivers/md/dm-flakey.c
index 97e446d54a151360fa1095311457ac149f426f38..6a2e8dd44a1b83b8fb45a4532458db3fb58db526 100644 (file)
--- a/drivers/md/dm-flakey.c
+++ b/drivers/md/dm-flakey.c
@@ -289,15 +289,13 @@ static int flakey_map(struct dm_target *ti, struct bio *bio)
                pb->bio_submitted = true;
 
                /*
-                * Map reads as normal only if corrupt_bio_byte set.
+                * Error reads if neither corrupt_bio_byte or drop_writes are set.
+                * Otherwise, flakey_end_io() will decide if the reads should be modified.
                 */
                if (bio_data_dir(bio) == READ) {
-                       /* If flags were specified, only corrupt those that match. */
-                       if (fc->corrupt_bio_byte && (fc->corrupt_bio_rw == READ) &&
-                           all_corrupt_bio_flags_match(bio, fc))
-                               goto map_bio;
-                       else
+                       if (!fc->corrupt_bio_byte && !test_bit(DROP_WRITES, &fc->flags))
                                return -EIO;
+                       goto map_bio;
                }
 
                /*
@@ -334,14 +332,21 @@ static int flakey_end_io(struct dm_target *ti, struct bio *bio, int error)
        struct flakey_c *fc = ti->private;
        struct per_bio_data *pb = dm_per_bio_data(bio, sizeof(struct per_bio_data));
 
-       /*
-        * Corrupt successful READs while in down state.
-        */
        if (!error && pb->bio_submitted && (bio_data_dir(bio) == READ)) {
-               if (fc->corrupt_bio_byte)
+               if (fc->corrupt_bio_byte && (fc->corrupt_bio_rw == READ) &&
+                   all_corrupt_bio_flags_match(bio, fc)) {
+                       /*
+                        * Corrupt successful matching READs while in down state.
+                        */
                        corrupt_bio_data(bio, fc);
-               else
+
+               } else if (!test_bit(DROP_WRITES, &fc->flags)) {
+                       /*
+                        * Error read during the down_interval if drop_writes
+                        * wasn't configured.
+                        */
                        return -EIO;
+               }
        }
 
        return error;