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authorMike Christie <michaelc@cs.wisc.edu>2008-08-19 18:45:30 -0500
committerJames Bottomley <James.Bottomley@HansenPartnership.com>2008-10-13 09:28:52 -0400
commit6000a368cd8e6da1caf101411bdb494cd6fb8b09 (patch)
tree4cd3333af00182e915aa96ffa49069f5f76976dc /include/linux/blkdev.h
parent056a44834950ffa51fafa6c76a720fa32e86851a (diff)
downloadblackbird-op-linux-6000a368cd8e6da1caf101411bdb494cd6fb8b09.tar.gz
blackbird-op-linux-6000a368cd8e6da1caf101411bdb494cd6fb8b09.zip
[SCSI] block: separate failfast into multiple bits.
Multipath is best at handling transport errors. If it gets a device error then there is not much the multipath layer can do. It will just access the same device but from a different path. This patch breaks up failfast into device, transport and driver errors. The multipath layers (md and dm mutlipath) only ask the lower levels to fast fail transport errors. The user of failfast, read ahead, will ask to fast fail on all errors. Note that blk_noretry_request will return true if any failfast bit is set. This allows drivers that do not support the multipath failfast bits to continue to fail on any failfast error like before. Drivers like scsi that are able to fail fast specific errors can check for the specific fail fast type. In the next patch I will convert scsi. Signed-off-by: Mike Christie <michaelc@cs.wisc.edu> Cc: Jens Axboe <jens.axboe@oracle.com> Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Diffstat (limited to 'include/linux/blkdev.h')
-rw-r--r--include/linux/blkdev.h15
1 files changed, 12 insertions, 3 deletions
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index a92d9e4ea96e..f3491d225268 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -87,7 +87,9 @@ enum {
*/
enum rq_flag_bits {
__REQ_RW, /* not set, read. set, write */
- __REQ_FAILFAST, /* no low level driver retries */
+ __REQ_FAILFAST_DEV, /* no driver retries of device errors */
+ __REQ_FAILFAST_TRANSPORT, /* no driver retries of transport errors */
+ __REQ_FAILFAST_DRIVER, /* no driver retries of driver errors */
__REQ_DISCARD, /* request to discard sectors */
__REQ_SORTED, /* elevator knows about this request */
__REQ_SOFTBARRIER, /* may not be passed by ioscheduler */
@@ -111,8 +113,10 @@ enum rq_flag_bits {
};
#define REQ_RW (1 << __REQ_RW)
+#define REQ_FAILFAST_DEV (1 << __REQ_FAILFAST_DEV)
+#define REQ_FAILFAST_TRANSPORT (1 << __REQ_FAILFAST_TRANSPORT)
+#define REQ_FAILFAST_DRIVER (1 << __REQ_FAILFAST_DRIVER)
#define REQ_DISCARD (1 << __REQ_DISCARD)
-#define REQ_FAILFAST (1 << __REQ_FAILFAST)
#define REQ_SORTED (1 << __REQ_SORTED)
#define REQ_SOFTBARRIER (1 << __REQ_SOFTBARRIER)
#define REQ_HARDBARRIER (1 << __REQ_HARDBARRIER)
@@ -560,7 +564,12 @@ enum {
#define blk_special_request(rq) ((rq)->cmd_type == REQ_TYPE_SPECIAL)
#define blk_sense_request(rq) ((rq)->cmd_type == REQ_TYPE_SENSE)
-#define blk_noretry_request(rq) ((rq)->cmd_flags & REQ_FAILFAST)
+#define blk_failfast_dev(rq) ((rq)->cmd_flags & REQ_FAILFAST_DEV)
+#define blk_failfast_transport(rq) ((rq)->cmd_flags & REQ_FAILFAST_TRANSPORT)
+#define blk_failfast_driver(rq) ((rq)->cmd_flags & REQ_FAILFAST_DRIVER)
+#define blk_noretry_request(rq) (blk_failfast_dev(rq) || \
+ blk_failfast_transport(rq) || \
+ blk_failfast_driver(rq))
#define blk_rq_started(rq) ((rq)->cmd_flags & REQ_STARTED)
#define blk_account_rq(rq) (blk_rq_started(rq) && (blk_fs_request(rq) || blk_discard_rq(rq)))
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