[SCSI] block: improve detail in I/O error messages

Classify severity of I/O errors for target, nexus, and
transport errors.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Hannes Reinecke <hare@suse.de>
Acked-by: Jens Axboe <jaxboe@fusionio.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>

1 files changed, 20 insertions, 3 deletions

diff --git a/block/blk-core.c b/block/blk-core.c
index 2f4002f79a24..b3cf121f1de9 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -2044,9 +2044,26 @@ bool blk_update_request(struct request *req, int error, unsigned int nr_bytes)
 
         if (error && req->cmd_type == REQ_TYPE_FS &&
             !(req->cmd_flags & REQ_QUIET)) {
-                printk(KERN_ERR "end_request: I/O error, dev %s, sector %llu\n",
-                                req->rq_disk ? req->rq_disk->disk_name : "?",
-                                (unsigned long long)blk_rq_pos(req));
+                char *error_type;
+
+                switch (error) {
+                case -ENOLINK:
+                        error_type = "recoverable transport";
+                        break;
+                case -EREMOTEIO:
+                        error_type = "critical target";
+                        break;
+                case -EBADE:
+                        error_type = "critical nexus";
+                        break;
+                case -EIO:
+                default:
+                        error_type = "I/O";
+                        break;
+                }
+                printk(KERN_ERR "end_request: %s error, dev %s, sector %llu\n",
+                       error_type, req->rq_disk ? req->rq_disk->disk_name : "?",
+                       (unsigned long long)blk_rq_pos(req));
         }
 
         blk_account_io_completion(req, nr_bytes);