Commit 695368ac authored by Alasdair G Kergon's avatar Alasdair G Kergon Committed by Linus Torvalds
Browse files

[PATCH] dm snapshot: fix freeing pending exception 



If a snapshot became invalid while there are outstanding pending_exceptions,
when pending_complete() processes each one it forgets to remove the
corresponding exception from its exception table before freeing it.

Fix this by moving the 'out:' label up one statement so that
remove_exception() is always called.  Then __invalidate_exception() no longer
needs to call it and its 'pe' argument become superfluous.

Signed-off-by: default avatarAlasdair G Kergon <agk@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 4b832e8d

drivers/md/dm-snap.c

+6 −10
Original line number Diff line number Diff line
@@ -631,8 +631,7 @@ static void error_bios(struct bio *bio) 
	}

}



static void __invalidate_snapshot(struct dm_snapshot *s,

				struct pending_exception *pe, int err)

static void __invalidate_snapshot(struct dm_snapshot *s, int err)

{

	if (!s->valid)

		return;
@@ -642,9 +641,6 @@ static void __invalidate_snapshot(struct dm_snapshot *s, 
	else if (err == -ENOMEM)

		DMERR("Invalidating snapshot: Unable to allocate exception.");



	if (pe)

		remove_exception(&pe->e);



	if (s->store.drop_snapshot)

		s->store.drop_snapshot(&s->store);
@@ -701,7 +697,7 @@ static void pending_complete(struct pending_exception *pe, int success) 
	if (!success) {

		/* Read/write error - snapshot is unusable */

		down_write(&s->lock);

		__invalidate_snapshot(s, pe, -EIO);

		__invalidate_snapshot(s, -EIO);

		error = 1;

		goto out;

	}
@@ -709,7 +705,7 @@ static void pending_complete(struct pending_exception *pe, int success) 
	e = alloc_exception();

	if (!e) {

		down_write(&s->lock);

		__invalidate_snapshot(s, pe, -ENOMEM);

		__invalidate_snapshot(s, -ENOMEM);

		error = 1;

		goto out;

	}
@@ -727,9 +723,9 @@ static void pending_complete(struct pending_exception *pe, int success) 
	 * in-flight exception from the list.

	 */

	insert_exception(&s->complete, e);

	remove_exception(&pe->e);



 out:

	remove_exception(&pe->e);

	snapshot_bios = bio_list_get(&pe->snapshot_bios);

	origin_bios = put_pending_exception(pe);
@@ -909,7 +905,7 @@ static int snapshot_map(struct dm_target *ti, struct bio *bio, 
	if (bio_rw(bio) == WRITE) {

		pe = __find_pending_exception(s, bio);

		if (!pe) {

			__invalidate_snapshot(s, pe, -ENOMEM);

			__invalidate_snapshot(s, -ENOMEM);

			r = -EIO;

			goto out_unlock;

		}
@@ -1035,7 +1031,7 @@ static int __origin_write(struct list_head *snapshots, struct bio *bio) 


		pe = __find_pending_exception(snap, bio);

		if (!pe) {

			__invalidate_snapshot(snap, pe, -ENOMEM);

			__invalidate_snapshot(snap, -ENOMEM);

			goto next_snapshot;

		}

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