diff options
Diffstat (limited to 'drivers/md/dm-snap.c')
| -rw-r--r-- | drivers/md/dm-snap.c | 20 |
1 files changed, 16 insertions, 4 deletions
diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c index 7c82d3ccce87..3903d7abeeeb 100644 --- a/drivers/md/dm-snap.c +++ b/drivers/md/dm-snap.c @@ -63,6 +63,13 @@ struct dm_snapshot { */ int valid; + /* + * The snapshot overflowed because of a write to the snapshot device. + * We don't have to invalidate the snapshot in this case, but we need + * to prevent further writes. + */ + int snapshot_overflowed; + /* Origin writes don't trigger exceptions until this is set */ int active; @@ -1152,6 +1159,7 @@ static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv) s->ti = ti; s->valid = 1; + s->snapshot_overflowed = 0; s->active = 0; atomic_set(&s->pending_exceptions_count, 0); s->exception_start_sequence = 0; @@ -1301,6 +1309,7 @@ static void __handover_exceptions(struct dm_snapshot *snap_src, snap_dest->ti->max_io_len = snap_dest->store->chunk_size; snap_dest->valid = snap_src->valid; + snap_dest->snapshot_overflowed = snap_src->snapshot_overflowed; /* * Set source invalid to ensure it receives no further I/O. @@ -1691,7 +1700,7 @@ static int snapshot_map(struct dm_target *ti, struct bio *bio) * to copy an exception */ down_write(&s->lock); - if (!s->valid) { + if (!s->valid || (unlikely(s->snapshot_overflowed) && bio_rw(bio) == WRITE)) { r = -EIO; goto out_unlock; } @@ -1715,7 +1724,7 @@ static int snapshot_map(struct dm_target *ti, struct bio *bio) pe = alloc_pending_exception(s); down_write(&s->lock); - if (!s->valid) { + if (!s->valid || s->snapshot_overflowed) { free_pending_exception(pe); r = -EIO; goto out_unlock; @@ -1730,7 +1739,8 @@ static int snapshot_map(struct dm_target *ti, struct bio *bio) pe = __find_pending_exception(s, pe, chunk); if (!pe) { - __invalidate_snapshot(s, -ENOMEM); + s->snapshot_overflowed = 1; + DMERR("Snapshot overflowed: Unable to allocate exception."); r = -EIO; goto out_unlock; } @@ -1990,6 +2000,8 @@ static void snapshot_status(struct dm_target *ti, status_type_t type, DMEMIT("Invalid"); else if (snap->merge_failed) DMEMIT("Merge failed"); + else if (snap->snapshot_overflowed) + DMEMIT("Overflow"); else { if (snap->store->type->usage) { sector_t total_sectors, sectors_allocated, @@ -2368,7 +2380,7 @@ static struct target_type origin_target = { static struct target_type snapshot_target = { .name = "snapshot", - .version = {1, 13, 0}, + .version = {1, 14, 0}, .module = THIS_MODULE, .ctr = snapshot_ctr, .dtr = snapshot_dtr, |