From 2913808eb56a6445a7b277eb8d17651c8defb035 Mon Sep 17 00:00:00 2001 From: Mikulas Patocka Date: Thu, 2 Apr 2009 19:55:25 +0100 Subject: [PATCH] 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: Mikulas Patocka Signed-off-by: Alasdair G Kergon --- drivers/md/dm-snap.c | 52 ++++++++++++++++++++++++-------------------- 1 file changed, 28 insertions(+), 24 deletions(-) diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c index 65ff82ff124e..87a2803ba6bd 100644 --- a/drivers/md/dm-snap.c +++ b/drivers/md/dm-snap.c @@ -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; } @@ -1083,11 +1081,14 @@ static int snapshot_map(struct dm_target *ti, struct bio *bio, * writeable. */ if (bio_rw(bio) == WRITE) { - pe = __find_pending_exception(s, bio); + pe = __lookup_pending_exception(s, chunk); if (!pe) { - __invalidate_snapshot(s, -ENOMEM); - r = -EIO; - goto out_unlock; + pe = __find_pending_exception(s, bio); + if (!pe) { + __invalidate_snapshot(s, -ENOMEM); + r = -EIO; + goto out_unlock; + } } remap_exception(s, &pe->e, bio, chunk); @@ -1217,10 +1218,13 @@ static int __origin_write(struct list_head *snapshots, struct bio *bio) if (e) goto next_snapshot; - pe = __find_pending_exception(snap, bio); + pe = __lookup_pending_exception(snap, chunk); if (!pe) { - __invalidate_snapshot(snap, -ENOMEM); - goto next_snapshot; + pe = __find_pending_exception(snap, bio); + if (!pe) { + __invalidate_snapshot(snap, -ENOMEM); + goto next_snapshot; + } } if (!primary_pe) {