Messages in this thread Patch in this message |  | | From | Mike Snitzer <> | | Subject | [PATCH v4 11/13] dm snapshot: make exceptions in other snapshots when merging | | Date | Fri, 20 Nov 2009 15:27:51 -0500 |
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From: Mikulas Patocka <mpatocka@redhat.com>
When there is one merging snapshot and other non-merging snapshots, snapshot_merge_process() must make exceptions in the non-merging snapshots.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> --- drivers/md/dm-snap.c | 32 +++++++++++++++++++++++++++++++- 1 files changed, 31 insertions(+), 1 deletions(-)
diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c index e41be70..2b5b083 100644 --- a/drivers/md/dm-snap.c +++ b/drivers/md/dm-snap.c @@ -255,6 +255,8 @@ struct origin { static struct list_head *_origins; static struct rw_semaphore _origins_lock; +static DECLARE_WAIT_QUEUE_HEAD(_pending_exception_done); + static int init_origin_hash(void) { int i; @@ -742,13 +744,18 @@ static int init_hash_tables(struct dm_snapshot *s) static void flush_bios(struct bio *bio); static void error_bios(struct bio *bio); +static int __origin_write(struct list_head *snapshots, + sector_t sector, struct bio *bio); + static void merge_callback(int read_err, unsigned long write_err, void *context); static void snapshot_merge_process(struct dm_snapshot *s) { int r; - chunk_t old_chunk, new_chunk; + chunk_t old_chunk, new_chunk, n; + struct origin *o; + int must_wait; struct dm_io_region src, dest; BUG_ON(!s->merge_running); @@ -779,6 +786,27 @@ static void snapshot_merge_process(struct dm_snapshot *s) src.sector = chunk_to_sector(s->store, new_chunk); src.count = dest.count; +test_again: + /* Reallocate other snapshots */ + must_wait = 0; + /* + * Merging snapshot already has the origin's __minimum_chunk_size() + * stored in split_io (see: snapshot_merge_resume); avoid rediscovery + */ + BUG_ON(!s->ti->split_io); + down_read(&_origins_lock); + o = __lookup_origin(s->origin->bdev); + for (n = 0; n < s->store->chunk_size; n += s->ti->split_io) { + r = __origin_write(&o->snapshots, dest.sector + n, NULL); + if (r == DM_MAPIO_SUBMITTED) + must_wait = 1; + } + up_read(&_origins_lock); + if (must_wait) { + sleep_on_timeout(&_pending_exception_done, HZ / 100 + 1); + goto test_again; + } + down_write(&s->lock); s->merge_write_interlock = old_chunk; s->merge_write_interlock_n = 1; @@ -1301,6 +1329,8 @@ static void pending_complete(struct dm_snap_pending_exception *pe, int success) origin_bios = bio_list_get(&pe->origin_bios); free_pending_exception(pe); + wake_up_all(&_pending_exception_done); + up_write(&s->lock); /* Submit any pending write bios */ -- 1.6.5.2
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