Mike, > -----Original Message----- > From: Mike Snitzer [mailto:snitzer@xxxxxxxxxx] > Sent: Tuesday, May 08, 2012 4:56 PM > To: dm-devel@xxxxxxxxxx > Cc: agk@xxxxxxxxxx; hare@xxxxxxx; Moger, Babu; sekharan@xxxxxxxxxx; > Mike Snitzer > Subject: [PATCH v2 4/5] dm mpath: add 'default_hw_handler' feature > > From: Hannes Reinecke <hare@xxxxxxx> > > When specifying the feature 'default_hw_handler' multipath will be use > the currently attached hardware handler instead of trying to attach the > one specified during table load. If no hardware handler is attached the > specified hardware handler will be used. I am trying to test these patches right now. What is the expectation from Multipath tools for this to work correctly. Do I have to pass following Parameters? hardware_handler "1 alua" features "1 default_hw_handler" It appears to me that the first line will forcibly load the alua handler even if the default handler is different. > > Leverages scsi_dh_attach's ability to increment the scsi_dh's reference > count if the same scsi_dh name is provided when attaching -- currently > attached scsi_dh name is determined with scsi_dh_attached_handler_name. > > Signed-off-by: Hannes Reinecke <hare@xxxxxxx> > Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx> > --- > drivers/md/dm-mpath.c | 27 +++++++++++++++++++++++---- > 1 files changed, 23 insertions(+), 4 deletions(-) > > diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c > index c351607..0fc6849 100644 > --- a/drivers/md/dm-mpath.c > +++ b/drivers/md/dm-mpath.c > @@ -84,6 +84,7 @@ struct multipath { > unsigned queue_io:1; /* Must we queue all I/O? */ > unsigned queue_if_no_path:1; /* Queue I/O if last path fails? */ > unsigned saved_queue_if_no_path:1; /* Saved state during > suspension */ > + unsigned use_default_hw_handler:1; /* Use attached device > handler */ > > unsigned pg_init_retries; /* Number of times to retry pg_init > */ > unsigned pg_init_count; /* Number of times pg_init > called */ > @@ -567,6 +568,7 @@ static struct pgpath *parse_path(struct dm_arg_set > *as, struct path_selector *ps > int r; > struct pgpath *p; > struct multipath *m = ti->private; > + struct request_queue *q = NULL; > > /* we need at least a path arg */ > if (as->argc < 1) { > @@ -585,9 +587,18 @@ static struct pgpath *parse_path(struct dm_arg_set > *as, struct path_selector *ps > goto bad; > } > > - if (m->hw_handler_name) { > - struct request_queue *q = bdev_get_queue(p->path.dev- > >bdev); > + if (m->use_default_hw_handler || m->hw_handler_name) > + q = bdev_get_queue(p->path.dev->bdev); > + > + if (m->use_default_hw_handler) { > + const char *attached_handler_name = > scsi_dh_attached_handler_name(q); > + if (attached_handler_name) { > + kfree(m->hw_handler_name); > + m->hw_handler_name = > kstrdup(attached_handler_name, GFP_KERNEL); > + } > + } > > + if (m->hw_handler_name) { > r = scsi_dh_attach(q, m->hw_handler_name); > if (r == -EBUSY) { > /* > @@ -759,7 +770,7 @@ static int parse_features(struct dm_arg_set *as, > struct multipath *m) > const char *arg_name; > > static struct dm_arg _args[] = { > - {0, 5, "invalid number of feature args"}, > + {0, 6, "invalid number of feature args"}, > {1, 50, "pg_init_retries must be between 1 and 50"}, > {0, 60000, "pg_init_delay_msecs must be between 0 and > 60000"}, > }; > @@ -780,6 +791,11 @@ static int parse_features(struct dm_arg_set *as, > struct multipath *m) > continue; > } > > + if (!strcasecmp(arg_name, "default_hw_handler")) { > + m->use_default_hw_handler = 1; > + continue; > + } > + > if (!strcasecmp(arg_name, "pg_init_retries") && > (argc >= 1)) { > r = dm_read_arg(_args + 1, as, &m->pg_init_retries, > &ti->error); > @@ -1363,13 +1379,16 @@ static int multipath_status(struct dm_target *ti, > status_type_t type, > else { > DMEMIT("%u ", m->queue_if_no_path + > (m->pg_init_retries > 0) * 2 + > - (m->pg_init_delay_msecs != > DM_PG_INIT_DELAY_DEFAULT) * 2); > + (m->pg_init_delay_msecs != > DM_PG_INIT_DELAY_DEFAULT) * 2 + > + m->use_default_hw_handler); > if (m->queue_if_no_path) > DMEMIT("queue_if_no_path "); > if (m->pg_init_retries) > DMEMIT("pg_init_retries %u ", m->pg_init_retries); > if (m->pg_init_delay_msecs != > DM_PG_INIT_DELAY_DEFAULT) > DMEMIT("pg_init_delay_msecs %u ", m- > >pg_init_delay_msecs); > + if (m->use_default_hw_handler) > + DMEMIT("default_hw_handler "); > } > > if (!m->hw_handler_name || type == STATUSTYPE_INFO) > -- > 1.7.4.4 -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
