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dm: fix REQ_RAHEAD handling 

A few (but not all) dm targets use a special EWOULDBLOCK error code for
failing REQ_RAHEAD requests that fail due to a lack of available resources.
But no one else knows about this magic code, and lower level drivers also
don't generate it when failing read-ahead requests for similar reasons.

So remove this special casing and ignore all additional error handling for
REQ_RAHEAD - if this was a real underlying error we'd get a normal read
once the real read comes in.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bart Van Assche <Bart.VanAssche@sandisk.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
hifive-unleashed-5.1
Christoph Hellwig 2017-06-03 09:37:57 +02:00 committed by Jens Axboe
parent f729b66fca
commit 9966afaf91
2 changed files with 3 additions and 3 deletions
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4
drivers/md/dm-raid1.c
View File

@ -1214,7 +1214,7 @@ static int mirror_map(struct dm_target *ti, struct bio *bio)
*/
if (!r || (r == -EWOULDBLOCK)) {
if (bio->bi_opf & REQ_RAHEAD)
return -EWOULDBLOCK;
return -EIO;
queue_bio(ms, bio, rw);
return DM_MAPIO_SUBMITTED;
@ -1258,7 +1258,7 @@ static int mirror_end_io(struct dm_target *ti, struct bio *bio, int error)
if (error == -EOPNOTSUPP)
return error;
if ((error == -EWOULDBLOCK) && (bio->bi_opf & REQ_RAHEAD))
if (bio->bi_opf & REQ_RAHEAD)
return error;
if (unlikely(error)) {

2
drivers/md/dm-stripe.c
View File

@ -384,7 +384,7 @@ static int stripe_end_io(struct dm_target *ti, struct bio *bio, int error)
if (!error)
return 0; /* I/O complete */
if ((error == -EWOULDBLOCK) && (bio->bi_opf & REQ_RAHEAD))
if (bio->bi_opf & REQ_RAHEAD)
return error;
if (error == -EOPNOTSUPP)