block/sd: Return -EREMOTEIO when WRITE SAME and DISCARD are disabled
When a storage device rejects a WRITE SAME command we will disable write
same functionality for the device and return -EREMOTEIO to the block
layer. -EREMOTEIO will in turn prevent DM from retrying the I/O and/or
failing the path.
Yiwen Jiang discovered a small race where WRITE SAME requests issued
simultaneously would cause -EIO to be returned. This happened because
any requests being prepared after WRITE SAME had been disabled for the
device caused us to return BLKPREP_KILL. The latter caused the block
layer to return -EIO upon completion.
To overcome this we introduce BLKPREP_INVALID which indicates that this
is an invalid request for the device. blk_peek_request() is modified to
return -EREMOTEIO in that case.
Reported-by: Yiwen Jiang <jiangyiwen@huawei.com>
Suggested-by: Mike Snitzer <snitzer@redhat.com>
Reviewed-by: Hannes Reinicke <hare@suse.de>
Reviewed-by: Ewan Milne <emilne@redhat.com>
Reviewed-by: Yiwen Jiang <jiangyiwen@huawei.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
diff --git a/block/blk-core.c b/block/blk-core.c
index 476244d..35607dd 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -2447,14 +2447,16 @@
rq = NULL;
break;
- } else if (ret == BLKPREP_KILL) {
+ } else if (ret == BLKPREP_KILL || ret == BLKPREP_INVALID) {
+ int err = (ret == BLKPREP_INVALID) ? -EREMOTEIO : -EIO;
+
rq->cmd_flags |= REQ_QUIET;
/*
* Mark this request as started so we don't trigger
* any debug logic in the end I/O path.
*/
blk_start_request(rq);
- __blk_end_request_all(rq, -EIO);
+ __blk_end_request_all(rq, err);
} else {
printk(KERN_ERR "%s: bad return=%d\n", __func__, ret);
break;
diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index ec163d0..6e841c6 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -761,7 +761,7 @@
break;
default:
- ret = BLKPREP_KILL;
+ ret = BLKPREP_INVALID;
goto out;
}
@@ -839,7 +839,7 @@
int ret;
if (sdkp->device->no_write_same)
- return BLKPREP_KILL;
+ return BLKPREP_INVALID;
BUG_ON(bio_offset(bio) || bio_iovec(bio).bv_len != sdp->sector_size);
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index d372ea8..a9b643a 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -681,9 +681,12 @@
/*
* q->prep_rq_fn return values
*/
-#define BLKPREP_OK 0 /* serve it */
-#define BLKPREP_KILL 1 /* fatal error, kill */
-#define BLKPREP_DEFER 2 /* leave on queue */
+enum {
+ BLKPREP_OK, /* serve it */
+ BLKPREP_KILL, /* fatal error, kill, return -EIO */
+ BLKPREP_DEFER, /* leave on queue */
+ BLKPREP_INVALID, /* invalid command, kill, return -EREMOTEIO */
+};
extern unsigned long blk_max_low_pfn, blk_max_pfn;