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/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;