dm: split dm_suspend io_lock hold into two

Change io_locking to allow processing flush in separate thread.

Because we have DMF_BLOCK_IO already set, any possible
new ios are queued in dm_requests now.

In the case of interrupting previous wait there can be more
ios queued (we unlocked io_lock for a while) but this is safe.

Signed-off-by: Milan Broz <mbroz@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
This commit is contained in:
Milan Broz 2008-02-08 02:10:27 +00:00 committed by Alasdair G Kergon
parent 73d410c013
commit 94d6351e14

View file

@ -1434,9 +1434,11 @@ int dm_suspend(struct mapped_device *md, unsigned suspend_flags)
if (noflush)
__merge_pushback_list(md);
up_write(&md->io_lock);
/* were we interrupted ? */
if (pending) {
down_write(&md->io_lock);
__flush_deferred_io(md);
up_write(&md->io_lock);
@ -1444,7 +1446,6 @@ int dm_suspend(struct mapped_device *md, unsigned suspend_flags)
r = -EINTR;
goto out; /* pushback list is already flushed, so skip flush */
}
up_write(&md->io_lock);
dm_table_postsuspend_targets(map);