[Date Prev][Date Next]   [Thread Prev][Thread Next]   [Thread Index] [Date Index] [Author Index]

[dm-devel] [PATCH 09/12] dm-snapshot-merge-make-exceptions-in-other-snapshots-when-merging



From: Mikulas Patocka <mpatocka redhat com>

When there is one merging snapshot and other non-merging snapshots, make
exceptions in non-merging snapshots while merging.

This is not yet complete (the exception is not made when remapping directly to
the origin), another patch fixes that.

Signed-off-by: Mikulas Patocka <mpatocka redhat com>
Reviewed-by: Mike Snitzer <snitzer redhat com>
---
 drivers/md/dm-snap.c |   31 +++++++++++++++++++++++++++++++
 1 files changed, 31 insertions(+), 0 deletions(-)

diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c
index 6a55d75..3be57ba 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;
@@ -653,6 +655,9 @@ 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);
 
@@ -660,6 +665,9 @@ static void snapshot_merge_process(struct dm_snapshot *s)
 {
 	int r;
 	chunk_t old_chunk, new_chunk;
+	struct origin *o;
+	chunk_t min_chunksize;
+	int must_wait;
 	struct dm_io_region src, dest;
 
 	BUG_ON(!s->merge_running);
@@ -695,6 +703,27 @@ 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 */
+	down_read(&_origins_lock);
+	o = __lookup_origin(s->origin->bdev);
+	must_wait = 0;
+	min_chunksize = __minimum_chunk_size(o);
+	if (min_chunksize) {
+		chunk_t n;
+		for (n = 0; n < s->store->chunk_size; n += min_chunksize) {
+			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;
@@ -1204,6 +1233,8 @@ 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 */
-- 
1.6.2.5


[Date Prev][Date Next]   [Thread Prev][Thread Next]   [Thread Index] [Date Index] [Author Index]