[PATCH 3.16 141/346] dm flakey: error READ bios during the down_interval

From: Ben Hutchings
Date: Sun Nov 13 2016 - 21:59:09 EST


3.16.39-rc1 review patch. If anyone has any objections, please let me know.

------------------

From: Mike Snitzer <snitzer@xxxxxxxxxx>

commit 99f3c90d0d85708e7401a81ce3314e50bf7f2819 upstream.

When the corrupt_bio_byte feature was introduced it caused READ bios to
no longer be errored with -EIO during the down_interval. This had to do
with the complexity of needing to submit READs if the corrupt_bio_byte
feature was used.

Fix it so READ bios are properly errored with -EIO; doing so early in
flakey_map() as long as there isn't a match for the corrupt_bio_byte
feature.

Fixes: a3998799fb4df ("dm flakey: add corrupt_bio_byte feature")
Reported-by: Akira Hayakawa <ruby.wktk@xxxxxxxxx>
Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx>
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
drivers/md/dm-flakey.c | 23 +++++++++++++++--------
1 file changed, 15 insertions(+), 8 deletions(-)

--- a/drivers/md/dm-flakey.c
+++ b/drivers/md/dm-flakey.c
@@ -287,10 +287,16 @@ static int flakey_map(struct dm_target *
pb->bio_submitted = true;

/*
- * Map reads as normal.
+ * Map reads as normal only if corrupt_bio_byte set.
*/
- if (bio_data_dir(bio) == READ)
- goto map_bio;
+ 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
+ return -EIO;
+ }

/*
* Drop writes?
@@ -328,12 +334,13 @@ static int flakey_end_io(struct dm_targe

/*
* Corrupt successful READs while in down state.
- * If flags were specified, only corrupt those that match.
*/
- if (fc->corrupt_bio_byte && !error && pb->bio_submitted &&
- (bio_data_dir(bio) == READ) && (fc->corrupt_bio_rw == READ) &&
- all_corrupt_bio_flags_match(bio, fc))
- corrupt_bio_data(bio, fc);
+ if (!error && pb->bio_submitted && (bio_data_dir(bio) == READ)) {
+ if (fc->corrupt_bio_byte)
+ corrupt_bio_data(bio, fc);
+ else
+ return -EIO;
+ }

return error;
}