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[PATCH] device-mapper: fix deadlocks in core (prep)

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Some code tidy-ups in preparation for the next patches.  Change
dm_table_pre/postsuspend_targets to accept NULL.  Use dm_suspended()
throughout.

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 2005-07-28 21:15:57 -07:00 committed by Linus Torvalds
parent 8c56ac3f3b
commit cf222b3769
2 changed files with 39 additions and 28 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
drivers/md/dm-table.c
View File

@ -869,11 +869,17 @@ static void suspend_targets(struct dm_table *t, unsigned postsuspend)
void dm_table_presuspend_targets(struct dm_table *t)
{
if (!t)
return;
return suspend_targets(t, 0);
}
void dm_table_postsuspend_targets(struct dm_table *t)
{
if (!t)
return;
return suspend_targets(t, 1);
}

61
drivers/md/dm.c
View File

@ -610,7 +610,7 @@ static int dm_flush_all(request_queue_t *q, struct gendisk *disk,
int ret = -ENXIO;
if (map) {
ret = dm_table_flush_all(md->map);
ret = dm_table_flush_all(map);
dm_table_put(map);
}
@ -854,7 +854,7 @@ static int __bind(struct mapped_device *md, struct dm_table *t)
write_unlock(&md->map_lock);
dm_table_get(t);
dm_table_event_callback(md->map, event_callback, md);
dm_table_event_callback(t, event_callback, md);
dm_table_set_restrictions(t, q);
return 0;
}
@ -935,7 +935,7 @@ void dm_put(struct mapped_device *md)
struct dm_table *map = dm_get_table(md);
if (atomic_dec_and_test(&md->holders)) {
if (!test_bit(DMF_SUSPENDED, &md->flags) && map) {
if (!dm_suspended(md)) {
dm_table_presuspend_targets(map);
dm_table_postsuspend_targets(map);
}
@ -971,7 +971,7 @@ int dm_swap_table(struct mapped_device *md, struct dm_table *table)
down_write(&md->lock);
/* device must be suspended */
if (!test_bit(DMF_SUSPENDED, &md->flags))
if (!dm_suspended(md))
goto out;
__unbind(md);
@ -988,7 +988,7 @@ out:
*/
static int __lock_fs(struct mapped_device *md)
{
int error = -ENOMEM;
int r = -ENOMEM;
if (test_and_set_bit(DMF_FS_LOCKED, &md->flags))
return 0;
@ -1003,7 +1003,7 @@ static int __lock_fs(struct mapped_device *md)
md->frozen_sb = freeze_bdev(md->frozen_bdev);
if (IS_ERR(md->frozen_sb)) {
error = PTR_ERR(md->frozen_sb);
r = PTR_ERR(md->frozen_sb);
goto out_bdput;
}
@ -1019,7 +1019,7 @@ out_bdput:
md->frozen_bdev = NULL;
out:
clear_bit(DMF_FS_LOCKED, &md->flags);
return error;
return r;
}
static void __unlock_fs(struct mapped_device *md)
@ -1045,20 +1045,20 @@ int dm_suspend(struct mapped_device *md)
{
struct dm_table *map;
DECLARE_WAITQUEUE(wait, current);
int error = -EINVAL;
int r = -EINVAL;
/* Flush I/O to the device. */
down_read(&md->lock);
if (test_bit(DMF_BLOCK_IO, &md->flags))
goto out_read_unlock;
map = dm_get_table(md);
if (map)
/* This does not get reverted if there's an error later. */
dm_table_presuspend_targets(map);
error = __lock_fs(md);
if (error) {
/* This does not get reverted if there's an error later. */
dm_table_presuspend_targets(map);
/* Flush I/O to the device. */
r = __lock_fs(md);
if (r) {
dm_table_put(map);
goto out_read_unlock;
}
@ -1071,7 +1071,7 @@ int dm_suspend(struct mapped_device *md)
* If the flag is already set we know another thread is trying to
* suspend as well, so we leave the fs locked for this thread.
*/
error = -EINVAL;
r = -EINVAL;
down_write(&md->lock);
if (test_and_set_bit(DMF_BLOCK_IO, &md->flags)) {
if (map)
@ -1106,15 +1106,14 @@ int dm_suspend(struct mapped_device *md)
remove_wait_queue(&md->wait, &wait);
/* were we interrupted ? */
error = -EINTR;
r = -EINTR;
if (atomic_read(&md->pending))
goto out_unfreeze;
set_bit(DMF_SUSPENDED, &md->flags);
map = dm_get_table(md);
if (map)
dm_table_postsuspend_targets(map);
dm_table_postsuspend_targets(map);
dm_table_put(map);
up_write(&md->lock);
@ -1125,25 +1124,29 @@ out_unfreeze:
clear_bit(DMF_BLOCK_IO, &md->flags);
out_write_unlock:
up_write(&md->lock);
return error;
return r;
out_read_unlock:
up_read(&md->lock);
return error;
return r;
}
int dm_resume(struct mapped_device *md)
{
int r = -EINVAL;
struct bio *def;
struct dm_table *map = dm_get_table(md);
struct dm_table *map = NULL;
down_write(&md->lock);
if (!map ||
!test_bit(DMF_SUSPENDED, &md->flags) ||
!dm_table_get_size(map)) {
if (!dm_suspended(md)) {
up_write(&md->lock);
dm_table_put(map);
return -EINVAL;
goto out;
}
map = dm_get_table(md);
if (!map || !dm_table_get_size(map)) {
up_write(&md->lock);
goto out;
}
dm_table_resume_targets(map);
@ -1155,9 +1158,11 @@ int dm_resume(struct mapped_device *md)
up_write(&md->lock);
__unlock_fs(md);
dm_table_unplug_all(map);
dm_table_put(map);
return 0;
r = 0;
out:
dm_table_put(map);
return r;
}
/*-----------------------------------------------------------------