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Commit d8ddb1cf authored by Mike Snitzer's avatar Mike Snitzer Committed by Alasdair G Kergon
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dm snapshot: report merge failure in status 



Set 'merge_failed' flag if a snapshot fails to merge.  Update
snapshot_status() to report "Merge failed" if 'merge_failed' is set.

Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
Signed-off-by: default avatarAlasdair G Kergon <agk@redhat.com>
parent 8a2d5286

drivers/md/dm-snap.c

+28 −2
Original line number Diff line number Diff line
@@ -71,7 +71,10 @@ struct dm_snapshot { 
	/* List of snapshots per Origin */

	struct list_head list;



	/* You can't use a snapshot if this is 0 (e.g. if full) */

	/*

	 * You can't use a snapshot if this is 0 (e.g. if full).

	 * A snapshot-merge target never clears this.

	 */

	int valid;



	/* Origin writes don't trigger exceptions until this is set */
@@ -107,6 +110,21 @@ struct dm_snapshot { 
	spinlock_t tracked_chunk_lock;

	struct hlist_head tracked_chunk_hash[DM_TRACKED_CHUNK_HASH_SIZE];



	/*

	 * The merge operation failed if this flag is set.

	 * Failure modes are handled as follows:

	 * - I/O error reading the header

	 *   	=> don't load the target; abort.

	 * - Header does not have "valid" flag set

	 *   	=> use the origin; forget about the snapshot.

	 * - I/O error when reading exceptions

	 *   	=> don't load the target; abort.

	 *         (We can't use the intermediate origin state.)

	 * - I/O error while merging

	 *	=> stop merging; set merge_failed; process I/O normally.

	 */

	int merge_failed;



	/* Wait for events based on state_bits */

	unsigned long state_bits;
@@ -900,9 +918,13 @@ static void snapshot_merge_next_chunks(struct dm_snapshot *s) 
	linear_chunks = s->store->type->prepare_merge(s->store, &old_chunk,

						      &new_chunk);

	if (linear_chunks <= 0) {

		if (linear_chunks < 0)

		if (linear_chunks < 0) {

			DMERR("Read error in exception store: "

			      "shutting down merge");

			down_write(&s->lock);

			s->merge_failed = 1;

			up_write(&s->lock);

		}

		goto shut;

	}
@@ -988,6 +1010,7 @@ static void merge_callback(int read_err, unsigned long write_err, void *context) 


shut:

	down_write(&s->lock);

	s->merge_failed = 1;

	b = __release_queued_bios_after_merge(s);

	up_write(&s->lock);

	error_bios(b);
@@ -1090,6 +1113,7 @@ static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv) 
	INIT_LIST_HEAD(&s->list);

	spin_lock_init(&s->pe_lock);

	s->state_bits = 0;

	s->merge_failed = 0;

	s->first_merging_chunk = 0;

	s->num_merging_chunks = 0;

	bio_list_init(&s->bios_queued_during_merge);
@@ -1835,6 +1859,8 @@ static int snapshot_status(struct dm_target *ti, status_type_t type, 


		if (!snap->valid)

			DMEMIT("Invalid");

		else if (snap->merge_failed)

			DMEMIT("Merge failed");

		else {

			if (snap->store->type->usage) {

				sector_t total_sectors, sectors_allocated,