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[PATCH] device-mapper multipath: Fix pg initialisation races

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Prevent more than one priority group initialisation function from being
outstanding at once.  Otherwise the completion functions interfere with each
other.  Also, reloading the table could reference a freed pointer.

Only reset queue_io in pg_init_complete if another pg_init isn't required.
Skip process_queued_ios if the queue is empty so that we only trigger a
pg_init if there's I/O.

Signed-off-by: Lars Marowsky-Bree <lmb@suse.de>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Alasdair G Kergon 2005-07-12 15:53:04 -07:00 committed by Linus Torvalds
parent 436d41087d
commit c3cd4f6b27
1 changed files with 23 additions and 14 deletions
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37
drivers/md/dm-mpath.c
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@ -63,6 +63,7 @@ struct multipath {
unsigned nr_priority_groups;
struct list_head priority_groups;
unsigned pg_init_required; /* pg_init needs calling? */
unsigned pg_init_in_progress; /* Only one pg_init allowed at once */
unsigned nr_valid_paths; /* Total number of usable paths */
struct pgpath *current_pgpath;
@ -308,7 +309,8 @@ static int map_io(struct multipath *m, struct bio *bio, struct mpath_io *mpio,
/* Queue for the daemon to resubmit */
bio_list_add(&m->queued_ios, bio);
m->queue_size++;
if (m->pg_init_required || !m->queue_io)
if ((m->pg_init_required && !m->pg_init_in_progress) ||
!m->queue_io)
queue_work(kmultipathd, &m->process_queued_ios);
pgpath = NULL;
r = 0;
@ -335,7 +337,7 @@ static int queue_if_no_path(struct multipath *m, unsigned queue_if_no_path)
m->saved_queue_if_no_path = m->queue_if_no_path;
m->queue_if_no_path = queue_if_no_path;
if (!m->queue_if_no_path)
if (!m->queue_if_no_path && m->queue_size)
queue_work(kmultipathd, &m->process_queued_ios);
spin_unlock_irqrestore(&m->lock, flags);
@ -380,25 +382,31 @@ static void process_queued_ios(void *data)
{
struct multipath *m = (struct multipath *) data;
struct hw_handler *hwh = &m->hw_handler;
struct pgpath *pgpath;
unsigned init_required, must_queue = 0;
struct pgpath *pgpath = NULL;
unsigned init_required = 0, must_queue = 1;
unsigned long flags;
spin_lock_irqsave(&m->lock, flags);
if (!m->queue_size)
goto out;
if (!m->current_pgpath)
__choose_pgpath(m);
pgpath = m->current_pgpath;
if ((pgpath && m->queue_io) ||
(!pgpath && m->queue_if_no_path))
must_queue = 1;
if ((pgpath && !m->queue_io) ||
(!pgpath && !m->queue_if_no_path))
must_queue = 0;
init_required = m->pg_init_required;
if (init_required)
if (m->pg_init_required && !m->pg_init_in_progress) {
m->pg_init_required = 0;
m->pg_init_in_progress = 1;
init_required = 1;
}
out:
spin_unlock_irqrestore(&m->lock, flags);
if (init_required)
@ -843,7 +851,7 @@ static int reinstate_path(struct pgpath *pgpath)
pgpath->path.is_active = 1;
m->current_pgpath = NULL;
if (!m->nr_valid_paths++)
if (!m->nr_valid_paths++ && m->queue_size)
queue_work(kmultipathd, &m->process_queued_ios);
queue_work(kmultipathd, &m->trigger_event);
@ -969,12 +977,13 @@ void dm_pg_init_complete(struct path *path, unsigned err_flags)
bypass_pg(m, pg, 1);
spin_lock_irqsave(&m->lock, flags);
if (!err_flags)
m->queue_io = 0;
else {
if (err_flags) {
m->current_pgpath = NULL;
m->current_pg = NULL;
}
} else if (!m->pg_init_required)
m->queue_io = 0;
m->pg_init_in_progress = 0;
queue_work(kmultipathd, &m->process_queued_ios);
spin_unlock_irqrestore(&m->lock, flags);
}