From ae11b1b36da726a8a93409b896704edc6b4f3402 Mon Sep 17 00:00:00 2001 From: Hannes Reinecke Date: Thu, 17 Jul 2008 17:49:02 -0700 Subject: [SCSI] scsi_dh: attach to hardware handler from dm-mpath multipath keeps a separate device table which may be more current than the built-in one. So we should make sure to always call ->attach whenever a multipath map with hardware handler is instantiated. And we should call ->detach on removal, too. [sekharan: update as per comments from agk] Signed-off-by: Hannes Reinecke Signed-off-by: Chandra Seetharaman Signed-off-by: James Bottomley --- drivers/md/dm-mpath.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) (limited to 'drivers/md/dm-mpath.c') diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c index fea966d66f9..71dd65aa31b 100644 --- a/drivers/md/dm-mpath.c +++ b/drivers/md/dm-mpath.c @@ -147,9 +147,12 @@ static struct priority_group *alloc_priority_group(void) static void free_pgpaths(struct list_head *pgpaths, struct dm_target *ti) { struct pgpath *pgpath, *tmp; + struct multipath *m = ti->private; list_for_each_entry_safe(pgpath, tmp, pgpaths, list) { list_del(&pgpath->list); + if (m->hw_handler_name) + scsi_dh_detach(bdev_get_queue(pgpath->path.dev->bdev)); dm_put_device(ti, pgpath->path.dev); free_pgpath(pgpath); } @@ -548,6 +551,7 @@ static struct pgpath *parse_path(struct arg_set *as, struct path_selector *ps, { int r; struct pgpath *p; + struct multipath *m = ti->private; /* we need at least a path arg */ if (as->argc < 1) { @@ -566,6 +570,15 @@ static struct pgpath *parse_path(struct arg_set *as, struct path_selector *ps, goto bad; } + if (m->hw_handler_name) { + r = scsi_dh_attach(bdev_get_queue(p->path.dev->bdev), + m->hw_handler_name); + if (r < 0) { + dm_put_device(ti, p->path.dev); + goto bad; + } + } + r = ps->type->add_path(ps, &p->path, as->argc, as->argv, &ti->error); if (r) { dm_put_device(ti, p->path.dev); -- cgit v1.2.3 From 7253a33434245ee8243897559188186df65f3611 Mon Sep 17 00:00:00 2001 From: Chandra Seetharaman Date: Wed, 1 Oct 2008 14:39:27 +0100 Subject: dm mpath: add missing path switching locking Moving the path activation to workqueue along with scsi_dh patches introduced a race. It is due to the fact that the current_pgpath (in the multipath data structure) can be modified if changes happen in any of the paths leading to the lun. If the changes lead to current_pgpath being set to NULL, then it leads to the invalid access which results in the panic below. This patch fixes that by storing the pgpath to activate in the multipath data structure and properly protecting it. Note that if activate_path is called twice in succession with different pgpath, with the second one being called before the first one is done, then activate path will be called twice for the second pgpath, which is fine. Unable to handle kernel paging request for data at address 0x00000020 Faulting instruction address: 0xd000000000aa1844 cpu 0x1: Vector: 300 (Data Access) at [c00000006b987a80] pc: d000000000aa1844: .activate_path+0x30/0x218 [dm_multipath] lr: c000000000087a2c: .run_workqueue+0x114/0x204 sp: c00000006b987d00 msr: 8000000000009032 dar: 20 dsisr: 40000000 current = 0xc0000000676bb3f0 paca = 0xc0000000006f3680 pid = 2528, comm = kmpath_handlerd enter ? for help [c00000006b987da0] c000000000087a2c .run_workqueue+0x114/0x204 [c00000006b987e40] c000000000088b58 .worker_thread+0x120/0x144 [c00000006b987f00] c00000000008ca70 .kthread+0x78/0xc4 [c00000006b987f90] c000000000027cc8 .kernel_thread+0x4c/0x68 Signed-off-by: Chandra Seetharaman Signed-off-by: Alasdair G Kergon --- drivers/md/dm-mpath.c | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-) (limited to 'drivers/md/dm-mpath.c') diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c index 71dd65aa31b..c2fcf28b4c7 100644 --- a/drivers/md/dm-mpath.c +++ b/drivers/md/dm-mpath.c @@ -63,6 +63,7 @@ struct multipath { const char *hw_handler_name; struct work_struct activate_path; + struct pgpath *pgpath_to_activate; unsigned nr_priority_groups; struct list_head priority_groups; unsigned pg_init_required; /* pg_init needs calling? */ @@ -146,6 +147,7 @@ static struct priority_group *alloc_priority_group(void) static void free_pgpaths(struct list_head *pgpaths, struct dm_target *ti) { + unsigned long flags; struct pgpath *pgpath, *tmp; struct multipath *m = ti->private; @@ -154,6 +156,10 @@ static void free_pgpaths(struct list_head *pgpaths, struct dm_target *ti) if (m->hw_handler_name) scsi_dh_detach(bdev_get_queue(pgpath->path.dev->bdev)); dm_put_device(ti, pgpath->path.dev); + spin_lock_irqsave(&m->lock, flags); + if (m->pgpath_to_activate == pgpath) + m->pgpath_to_activate = NULL; + spin_unlock_irqrestore(&m->lock, flags); free_pgpath(pgpath); } } @@ -421,6 +427,7 @@ static void process_queued_ios(struct work_struct *work) __choose_pgpath(m); pgpath = m->current_pgpath; + m->pgpath_to_activate = m->current_pgpath; if ((pgpath && !m->queue_io) || (!pgpath && !m->queue_if_no_path)) @@ -1093,8 +1100,15 @@ static void activate_path(struct work_struct *work) int ret; struct multipath *m = container_of(work, struct multipath, activate_path); - struct dm_path *path = &m->current_pgpath->path; + struct dm_path *path; + unsigned long flags; + spin_lock_irqsave(&m->lock, flags); + path = &m->pgpath_to_activate->path; + m->pgpath_to_activate = NULL; + spin_unlock_irqrestore(&m->lock, flags); + if (!path) + return; ret = scsi_dh_activate(bdev_get_queue(path->dev->bdev)); pg_init_done(path, ret); } -- cgit v1.2.3 From 224cb3e981f1b2f9f93dbd49eaef505d17d894c2 Mon Sep 17 00:00:00 2001 From: Mike Anderson Date: Fri, 29 Aug 2008 09:36:09 +0200 Subject: dm: Call blk_abort_queue on failed paths Signed-off-by: Mike Anderson Signed-off-by: Jens Axboe --- drivers/md/dm-mpath.c | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-) (limited to 'drivers/md/dm-mpath.c') diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c index c2fcf28b4c7..3d3848132c6 100644 --- a/drivers/md/dm-mpath.c +++ b/drivers/md/dm-mpath.c @@ -33,6 +33,7 @@ struct pgpath { unsigned fail_count; /* Cumulative failure count */ struct dm_path path; + struct work_struct deactivate_path; }; #define path_to_pgpath(__pgp) container_of((__pgp), struct pgpath, path) @@ -112,6 +113,7 @@ static struct workqueue_struct *kmultipathd, *kmpath_handlerd; static void process_queued_ios(struct work_struct *work); static void trigger_event(struct work_struct *work); static void activate_path(struct work_struct *work); +static void deactivate_path(struct work_struct *work); /*----------------------------------------------- @@ -122,8 +124,10 @@ static struct pgpath *alloc_pgpath(void) { struct pgpath *pgpath = kzalloc(sizeof(*pgpath), GFP_KERNEL); - if (pgpath) + if (pgpath) { pgpath->path.is_active = 1; + INIT_WORK(&pgpath->deactivate_path, deactivate_path); + } return pgpath; } @@ -133,6 +137,14 @@ static void free_pgpath(struct pgpath *pgpath) kfree(pgpath); } +static void deactivate_path(struct work_struct *work) +{ + struct pgpath *pgpath = + container_of(work, struct pgpath, deactivate_path); + + blk_abort_queue(pgpath->path.dev->bdev->bd_disk->queue); +} + static struct priority_group *alloc_priority_group(void) { struct priority_group *pg; @@ -870,6 +882,7 @@ static int fail_path(struct pgpath *pgpath) pgpath->path.dev->name, m->nr_valid_paths); queue_work(kmultipathd, &m->trigger_event); + queue_work(kmultipathd, &pgpath->deactivate_path); out: spin_unlock_irqrestore(&m->lock, flags); -- cgit v1.2.3 From 01460f3520c100010aacc8f8500cafcb17ce4665 Mon Sep 17 00:00:00 2001 From: Benjamin Marzinski Date: Fri, 10 Oct 2008 13:36:57 +0100 Subject: dm mpath: use more error codes This patch allows path errors from the multipath ctr function to propagate up to userspace as errno values from the ioctl() call. This is in response to https://www.redhat.com/archives/dm-devel/2008-May/msg00000.html and https://bugzilla.redhat.com/show_bug.cgi?id=444421 The patch only lets through the errors that it needs to in order to get the path errors from parse_path(). Signed-off-by: Benjamin Marzinski Signed-off-by: Alasdair G Kergon --- drivers/md/dm-mpath.c | 22 ++++++++++++---------- 1 file changed, 12 insertions(+), 10 deletions(-) (limited to 'drivers/md/dm-mpath.c') diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c index c2fcf28b4c7..c2ff77d77a5 100644 --- a/drivers/md/dm-mpath.c +++ b/drivers/md/dm-mpath.c @@ -563,12 +563,12 @@ static struct pgpath *parse_path(struct arg_set *as, struct path_selector *ps, /* we need at least a path arg */ if (as->argc < 1) { ti->error = "no device given"; - return NULL; + return ERR_PTR(-EINVAL); } p = alloc_pgpath(); if (!p) - return NULL; + return ERR_PTR(-ENOMEM); r = dm_get_device(ti, shift(as), ti->begin, ti->len, dm_table_get_mode(ti->table), &p->path.dev); @@ -596,7 +596,7 @@ static struct pgpath *parse_path(struct arg_set *as, struct path_selector *ps, bad: free_pgpath(p); - return NULL; + return ERR_PTR(r); } static struct priority_group *parse_priority_group(struct arg_set *as, @@ -614,14 +614,14 @@ static struct priority_group *parse_priority_group(struct arg_set *as, if (as->argc < 2) { as->argc = 0; - ti->error = "not enough priority group aruments"; - return NULL; + ti->error = "not enough priority group arguments"; + return ERR_PTR(-EINVAL); } pg = alloc_priority_group(); if (!pg) { ti->error = "couldn't allocate priority group"; - return NULL; + return ERR_PTR(-ENOMEM); } pg->m = m; @@ -654,8 +654,10 @@ static struct priority_group *parse_priority_group(struct arg_set *as, path_args.argv = as->argv; pgpath = parse_path(&path_args, &pg->ps, ti); - if (!pgpath) + if (IS_ERR(pgpath)) { + r = PTR_ERR(pgpath); goto bad; + } pgpath->pg = pg; list_add_tail(&pgpath->list, &pg->pgpaths); @@ -666,7 +668,7 @@ static struct priority_group *parse_priority_group(struct arg_set *as, bad: free_priority_group(pg, ti); - return NULL; + return ERR_PTR(r); } static int parse_hw_handler(struct arg_set *as, struct multipath *m) @@ -785,8 +787,8 @@ static int multipath_ctr(struct dm_target *ti, unsigned int argc, struct priority_group *pg; pg = parse_priority_group(&as, m); - if (!pg) { - r = -EINVAL; + if (IS_ERR(pg)) { + r = PTR_ERR(pg); goto bad; } -- cgit v1.2.3 From 6680073d3ec7c6dbdbf77870bf1fea869767d779 Mon Sep 17 00:00:00 2001 From: Kiyoshi Ueda Date: Fri, 10 Oct 2008 13:36:58 +0100 Subject: dm mpath: remove is_active from struct dm_path This patch moves 'is_active' from struct dm_path to struct pgpath as it does not need exporting. Signed-off-by: Kiyoshi Ueda Signed-off-by: Jun'ichi Nomura Signed-off-by: Alasdair G Kergon --- drivers/md/dm-mpath.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) (limited to 'drivers/md/dm-mpath.c') diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c index c2ff77d77a5..b2ab8489d0e 100644 --- a/drivers/md/dm-mpath.c +++ b/drivers/md/dm-mpath.c @@ -30,6 +30,7 @@ struct pgpath { struct list_head list; struct priority_group *pg; /* Owning PG */ + unsigned is_active; /* Path status */ unsigned fail_count; /* Cumulative failure count */ struct dm_path path; @@ -123,7 +124,7 @@ static struct pgpath *alloc_pgpath(void) struct pgpath *pgpath = kzalloc(sizeof(*pgpath), GFP_KERNEL); if (pgpath) - pgpath->path.is_active = 1; + pgpath->is_active = 1; return pgpath; } @@ -854,13 +855,13 @@ static int fail_path(struct pgpath *pgpath) spin_lock_irqsave(&m->lock, flags); - if (!pgpath->path.is_active) + if (!pgpath->is_active) goto out; DMWARN("Failing path %s.", pgpath->path.dev->name); pgpath->pg->ps.type->fail_path(&pgpath->pg->ps, &pgpath->path); - pgpath->path.is_active = 0; + pgpath->is_active = 0; pgpath->fail_count++; m->nr_valid_paths--; @@ -890,7 +891,7 @@ static int reinstate_path(struct pgpath *pgpath) spin_lock_irqsave(&m->lock, flags); - if (pgpath->path.is_active) + if (pgpath->is_active) goto out; if (!pgpath->pg->ps.type->reinstate_path) { @@ -904,7 +905,7 @@ static int reinstate_path(struct pgpath *pgpath) if (r) goto out; - pgpath->path.is_active = 1; + pgpath->is_active = 1; m->current_pgpath = NULL; if (!m->nr_valid_paths++ && m->queue_size) @@ -1292,7 +1293,7 @@ static int multipath_status(struct dm_target *ti, status_type_t type, list_for_each_entry(p, &pg->pgpaths, list) { DMEMIT("%s %s %u ", p->path.dev->name, - p->path.is_active ? "A" : "F", + p->is_active ? "A" : "F", p->fail_count); if (pg->ps.type->status) sz += pg->ps.type->status(&pg->ps, -- cgit v1.2.3