From 18776c7316545482a02bfaa2629a2aa1afc48357 Mon Sep 17 00:00:00 2001 From: Mikulas Patocka Date: Thu, 13 Nov 2008 23:38:52 +0000 Subject: dm raid1: flush workqueue before destruction We queue work on keventd queue --- so this queue must be flushed in the destructor. Otherwise, keventd could access mirror_set after it was freed. Signed-off-by: Mikulas Patocka Signed-off-by: Alasdair G Kergon Cc: stable@kernel.org --- drivers/md/dm-raid1.c | 1 + 1 file changed, 1 insertion(+) (limited to 'drivers/md') diff --git a/drivers/md/dm-raid1.c b/drivers/md/dm-raid1.c index 9d7b53ed75b..ec43f9fa4b2 100644 --- a/drivers/md/dm-raid1.c +++ b/drivers/md/dm-raid1.c @@ -1032,6 +1032,7 @@ static void mirror_dtr(struct dm_target *ti) del_timer_sync(&ms->timer); flush_workqueue(ms->kmirrord_wq); + flush_scheduled_work(); dm_kcopyd_client_destroy(ms->kcopyd_client); destroy_workqueue(ms->kmirrord_wq); free_context(ms, ti, ms->nr_mirrors); -- cgit v1.2.3 From 6edebdee48729ab4ba564bbfcb8dbf6a6cd68a39 Mon Sep 17 00:00:00 2001 From: Heinz Mauelshagen Date: Thu, 13 Nov 2008 23:38:56 +0000 Subject: dm stripe: fix init failure Don't proceed if dm_stripe_init() fails to register itself as a dm target. Signed-off-by: Heinz Mauelshagen Signed-off-by: Alasdair G Kergon --- drivers/md/dm-stripe.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'drivers/md') diff --git a/drivers/md/dm-stripe.c b/drivers/md/dm-stripe.c index a2d068dbe9e..9e4ef88d421 100644 --- a/drivers/md/dm-stripe.c +++ b/drivers/md/dm-stripe.c @@ -320,8 +320,10 @@ int __init dm_stripe_init(void) int r; r = dm_register_target(&stripe_target); - if (r < 0) + if (r < 0) { DMWARN("target registration failed"); + return r; + } kstriped = create_singlethread_workqueue("kstriped"); if (!kstriped) { -- cgit v1.2.3 From b81aa1c79201cb424114fd198607951900babe18 Mon Sep 17 00:00:00 2001 From: Chandra Seetharaman Date: Thu, 13 Nov 2008 23:39:00 +0000 Subject: dm mpath: avoid attempting to activate null path Path activation code is called even when the pgpath is NULL. This could lead to a panic in activate_path(). Such a panic is seen in -rt kernel. This problem has been there before the pg_init() was moved to a workqueue. Signed-off-by: Chandra Seetharaman Signed-off-by: Alasdair G Kergon --- drivers/md/dm-mpath.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'drivers/md') diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c index 4840733cd90..58b1015260f 100644 --- a/drivers/md/dm-mpath.c +++ b/drivers/md/dm-mpath.c @@ -441,13 +441,13 @@ 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)) must_queue = 0; - if (m->pg_init_required && !m->pg_init_in_progress) { + if (m->pg_init_required && !m->pg_init_in_progress && pgpath) { + m->pgpath_to_activate = pgpath; m->pg_init_count++; m->pg_init_required = 0; m->pg_init_in_progress = 1; -- cgit v1.2.3 From 14e98c5ca8bed825f65cbf11cb0ffd2c09dac2f4 Mon Sep 17 00:00:00 2001 From: Chandra Seetharaman Date: Thu, 13 Nov 2008 23:39:06 +0000 Subject: dm mpath: warn if args ignored Currently dm ignores the parameters provided to hardware handlers without providing any notifications to the user. This patch just prints a warning message so that the user knows that the arguments are ignored. Signed-off-by: Chandra Seetharaman Signed-off-by: Alasdair G Kergon --- drivers/md/dm-mpath.c | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'drivers/md') diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c index 58b1015260f..3d7f4923cd1 100644 --- a/drivers/md/dm-mpath.c +++ b/drivers/md/dm-mpath.c @@ -708,6 +708,10 @@ static int parse_hw_handler(struct arg_set *as, struct multipath *m) m->hw_handler_name = NULL; return -EINVAL; } + + if (hw_argc > 1) + DMWARN("Ignoring user-specified arguments for " + "hardware handler \"%s\"", m->hw_handler_name); consume(as, hw_argc - 1); return 0; -- cgit v1.2.3 From d221d2e77696e70e94b13989ea15db2ba5b34f8e Mon Sep 17 00:00:00 2001 From: Mikulas Patocka Date: Thu, 13 Nov 2008 23:39:10 +0000 Subject: dm: move pending queue wake_up end_io_acct This doesn't fix any bug, just moves wake_up immediately after decrementing md->pending, for better code readability. It must be clear to anyone manipulating md->pending to wake up the queue if md->pending reaches zero, so move the wakeup as close to the decrementing as possible. Signed-off-by: Mikulas Patocka Signed-off-by: Alasdair G Kergon --- drivers/md/dm.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) (limited to 'drivers/md') diff --git a/drivers/md/dm.c b/drivers/md/dm.c index 6963ad14840..dc25d8a07bc 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -375,7 +375,7 @@ static void start_io_acct(struct dm_io *io) dm_disk(md)->part0.in_flight = atomic_inc_return(&md->pending); } -static int end_io_acct(struct dm_io *io) +static void end_io_acct(struct dm_io *io) { struct mapped_device *md = io->md; struct bio *bio = io->bio; @@ -391,7 +391,9 @@ static int end_io_acct(struct dm_io *io) dm_disk(md)->part0.in_flight = pending = atomic_dec_return(&md->pending); - return !pending; + /* nudge anyone waiting on suspend queue */ + if (!pending) + wake_up(&md->wait); } /* @@ -499,9 +501,7 @@ static void dec_pending(struct dm_io *io, int error) spin_unlock_irqrestore(&io->md->pushback_lock, flags); } - if (end_io_acct(io)) - /* nudge anyone waiting on suspend queue */ - wake_up(&io->md->wait); + end_io_acct(io); if (io->error != DM_ENDIO_REQUEUE) { blk_add_trace_bio(io->md->queue, io->bio, -- cgit v1.2.3 From 8a57dfc6f943c92b861c9a19b0c86ddcb2aba768 Mon Sep 17 00:00:00 2001 From: Chandra Seetharaman Date: Thu, 13 Nov 2008 23:39:14 +0000 Subject: dm: avoid destroying table in dm_any_congested dm_any_congested() just checks for the DMF_BLOCK_IO and has no code to make sure that suspend waits for dm_any_congested() to complete. This patch adds such a check. Without it, a race can occur with dm_table_put() attempting to destroying the table in the wrong thread, the one running dm_any_congested() which is meant to be quick and return immediately. Two examples of problems: 1. Sleeping functions called from congested code, the caller of which holds a spin lock. 2. An ABBA deadlock between pdflush and multipathd. The two locks in contention are inode lock and kernel lock. Signed-off-by: Chandra Seetharaman Signed-off-by: Mikulas Patocka Signed-off-by: Alasdair G Kergon --- drivers/md/dm.c | 24 ++++++++++++++++-------- 1 file changed, 16 insertions(+), 8 deletions(-) (limited to 'drivers/md') diff --git a/drivers/md/dm.c b/drivers/md/dm.c index dc25d8a07bc..c99e4728ff4 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -937,16 +937,24 @@ static void dm_unplug_all(struct request_queue *q) static int dm_any_congested(void *congested_data, int bdi_bits) { - int r; - struct mapped_device *md = (struct mapped_device *) congested_data; - struct dm_table *map = dm_get_table(md); + int r = bdi_bits; + struct mapped_device *md = congested_data; + struct dm_table *map; - if (!map || test_bit(DMF_BLOCK_IO, &md->flags)) - r = bdi_bits; - else - r = dm_table_any_congested(map, bdi_bits); + atomic_inc(&md->pending); + + if (!test_bit(DMF_BLOCK_IO, &md->flags)) { + map = dm_get_table(md); + if (map) { + r = dm_table_any_congested(map, bdi_bits); + dm_table_put(map); + } + } + + if (!atomic_dec_return(&md->pending)) + /* nudge anyone waiting on suspend queue */ + wake_up(&md->wait); - dm_table_put(map); return r; } -- cgit v1.2.3