On Mon, Jul 26 2010 at 9:30am -0400, Mike Snitzer <snitzer@xxxxxxxxxx> wrote: > Hi, > > I have been implementing discard support for the various DM targets. I > have a LUN that requires a 4K alignment for all discard requests. I > forced the issue (by misconfiguring the alignment such that discards > would be misaligned). Multipath failed the path once the SCSI layer got > the following error. > > My question: shouldn't mpath _not_ fail the path for "Illegal > Request".. "Parameter value invalid"? The same request would fail on > any path given that the failure is on the target side (rejecting the > malformed discard request). Following setup is ext4 FS ontop of linear > DM mapping (dm-2) ontop of request-based mpath mapping (dm-1): > > EXT4-fs (dm-2): mounted filesystem with ordered data mode > sd 3:0:0:0: [sda] Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE > sd 3:0:0:0: [sda] Sense Key : Illegal Request [current] > Info fld=0x0 > sd 3:0:0:0: [sda] Add. Sense: Parameter value invalid > sd 3:0:0:0: [sda] CDB: Write same(16): 93 08 00 00 00 00 00 00 45 82 00 00 03 00 00 00 > end_request: I/O error, dev sda, sector 17794 > device-mapper: multipath: Failing path 8:0. The following patch sorts this out in multipath; special-cases discard requests so that they don't enduce path failures: diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c index ec2b43e..125c80f 100644 --- a/drivers/md/dm-mpath.c +++ b/drivers/md/dm-mpath.c @@ -1272,6 +1272,9 @@ static int do_end_io(struct multipath *m, struct request *clone, if (error == -EOPNOTSUPP) return error; + if (clone->cmd_flags & REQ_DISCARD) + return error; /* pass all discard request failures up */ + if (mpio->pgpath) fail_path(mpio->pgpath); -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
