diff options
author | Alasdair G Kergon <agk@redhat.com> | 2009-12-11 02:52:23 +0300 |
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committer | Alasdair G Kergon <agk@redhat.com> | 2009-12-11 02:52:23 +0300 |
commit | a794015597a2d9b437470c7692aac77e5fc08cd2 (patch) | |
tree | d25dd56edd53f8f1890ed005b5531ccfa07c28ee /drivers | |
parent | 1d0f3ce83200edc5d43723c77c62b09ad6560294 (diff) | |
download | linux-a794015597a2d9b437470c7692aac77e5fc08cd2.tar.xz |
dm: bind new table before destroying old
When replacing a mapped device's table during a 'resume', delay the
destruction of the old table until the new one is successfully in place.
This will make it easier for a later patch to transfer internal state
information from the old table to the new one (something we do not currently
support) while giving us more options for reversion if a later part
of the operation fails.
Devices are always in the suspended state during dm_swap_table().
This patch reinforces the requirement that all I/O must have been
flushed from the table targets while in this state (including any in
workqueues). In the case of 'noflush' suspending, unprocessed
I/O should have been 'pushed back' to the dm core prior to this point,
for resubmission after the new table is in place.
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Diffstat (limited to 'drivers')
-rw-r--r-- | drivers/md/dm-table.c | 3 | ||||
-rw-r--r-- | drivers/md/dm.c | 16 |
2 files changed, 14 insertions, 5 deletions
diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c index 1a6cb3c7822e..3162b9c3c3f2 100644 --- a/drivers/md/dm-table.c +++ b/drivers/md/dm-table.c @@ -237,6 +237,9 @@ void dm_table_destroy(struct dm_table *t) { unsigned int i; + if (!t) + return; + while (atomic_read(&t->holders)) msleep(1); smp_mb(); diff --git a/drivers/md/dm.c b/drivers/md/dm.c index 16f759fe04fe..255b75c61544 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -2077,19 +2077,23 @@ static int __bind(struct mapped_device *md, struct dm_table *t, return 0; } -static void __unbind(struct mapped_device *md) +/* + * Returns unbound table for the caller to free. + */ +static struct dm_table *__unbind(struct mapped_device *md) { struct dm_table *map = md->map; unsigned long flags; if (!map) - return; + return NULL; dm_table_event_callback(map, NULL, NULL); write_lock_irqsave(&md->map_lock, flags); md->map = NULL; write_unlock_irqrestore(&md->map_lock, flags); - dm_table_destroy(map); + + return map; } /* @@ -2182,7 +2186,7 @@ void dm_put(struct mapped_device *md) } dm_sysfs_exit(md); dm_table_put(map); - __unbind(md); + dm_table_destroy(__unbind(md)); free_dev(md); } } @@ -2368,6 +2372,7 @@ static void dm_rq_barrier_work(struct work_struct *work) */ int dm_swap_table(struct mapped_device *md, struct dm_table *table) { + struct dm_table *map; struct queue_limits limits; int r = -EINVAL; @@ -2388,8 +2393,9 @@ int dm_swap_table(struct mapped_device *md, struct dm_table *table) goto out; } - __unbind(md); + map = __unbind(md); r = __bind(md, table, &limits); + dm_table_destroy(map); out: mutex_unlock(&md->suspend_lock); |