Commit 2913808e authored by Mikulas Patocka's avatar Mikulas Patocka Committed by Alasdair G Kergon
Browse files

dm snapshot: refactor __find_pending_exception 



Move looking-up of a pending exception from __find_pending_exception to another
function.

Cc: stable@kernel.org
Signed-off-by: default avatarMikulas Patocka <mpatocka@redhat.com>
Signed-off-by: default avatarAlasdair G Kergon <agk@redhat.com>
parent b64b6bf4

drivers/md/dm-snap.c

+28 −24
Original line number Diff line number Diff line
@@ -972,6 +972,17 @@ static void start_copy(struct dm_snap_pending_exception *pe) 
		    &src, 1, &dest, 0, copy_callback, pe);

}



static struct dm_snap_pending_exception *

__lookup_pending_exception(struct dm_snapshot *s, chunk_t chunk)

{

	struct dm_snap_exception *e = lookup_exception(&s->pending, chunk);



	if (!e)

		return NULL;



	return container_of(e, struct dm_snap_pending_exception, e);

}



/*

 * Looks to see if this snapshot already has a pending exception

 * for this chunk, otherwise it allocates a new one and inserts
@@ -983,20 +994,9 @@ static void start_copy(struct dm_snap_pending_exception *pe) 
static struct dm_snap_pending_exception *

__find_pending_exception(struct dm_snapshot *s, struct bio *bio)

{

	struct dm_snap_exception *e;

	struct dm_snap_pending_exception *pe;

	struct dm_snap_pending_exception *pe, *pe2;

	chunk_t chunk = sector_to_chunk(s, bio->bi_sector);



	/*

	 * Is there a pending exception for this already ?

	 */

	e = lookup_exception(&s->pending, chunk);

	if (e) {

		/* cast the exception to a pending exception */

		pe = container_of(e, struct dm_snap_pending_exception, e);

		goto out;

	}



	/*

	 * Create a new pending exception, we don't want

	 * to hold the lock while we do this.
@@ -1010,11 +1010,10 @@ __find_pending_exception(struct dm_snapshot *s, struct bio *bio) 
		return NULL;

	}



	e = lookup_exception(&s->pending, chunk);

	if (e) {

	pe2 = __lookup_pending_exception(s, chunk);

	if (pe2) {

		free_pending_exception(pe);

		pe = container_of(e, struct dm_snap_pending_exception, e);

		goto out;

		return pe2;

	}



	pe->e.old_chunk = chunk;
@@ -1032,7 +1031,6 @@ __find_pending_exception(struct dm_snapshot *s, struct bio *bio) 
	get_pending_exception(pe);

	insert_exception(&s->pending, &pe->e);



 out:

	return pe;

}
@@ -1083,12 +1081,15 @@ static int snapshot_map(struct dm_target *ti, struct bio *bio, 
	 * writeable.

	 */

	if (bio_rw(bio) == WRITE) {

		pe = __lookup_pending_exception(s, chunk);

		if (!pe) {

			pe = __find_pending_exception(s, bio);

			if (!pe) {

				__invalidate_snapshot(s, -ENOMEM);

				r = -EIO;

				goto out_unlock;

			}

		}



		remap_exception(s, &pe->e, bio, chunk);

		bio_list_add(&pe->snapshot_bios, bio);
@@ -1217,11 +1218,14 @@ static int __origin_write(struct list_head *snapshots, struct bio *bio) 
		if (e)

			goto next_snapshot;



		pe = __lookup_pending_exception(snap, chunk);

		if (!pe) {

			pe = __find_pending_exception(snap, bio);

			if (!pe) {

				__invalidate_snapshot(snap, -ENOMEM);

				goto next_snapshot;

			}

		}



		if (!primary_pe) {

			/*