diff options
| -rw-r--r-- | drivers/md/dm-snap.c | 295 |
1 files changed, 174 insertions, 121 deletions
diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c index 475514bda9d..14bd1a1815b 100644 --- a/drivers/md/dm-snap.c +++ b/drivers/md/dm-snap.c @@ -392,6 +392,8 @@ static void read_snapshot_metadata(struct dm_snapshot *s) down_write(&s->lock); s->valid = 0; up_write(&s->lock); + + dm_table_event(s->table); } } @@ -601,6 +603,11 @@ static void error_bios(struct bio *bio) } } +static inline void error_snapshot_bios(struct pending_exception *pe) +{ + error_bios(bio_list_get(&pe->snapshot_bios)); +} + static struct bio *__flush_bios(struct pending_exception *pe) { /* @@ -616,6 +623,28 @@ static struct bio *__flush_bios(struct pending_exception *pe) return NULL; } +static void __invalidate_snapshot(struct dm_snapshot *s, + struct pending_exception *pe, int err) +{ + if (!s->valid) + return; + + if (err == -EIO) + DMERR("Invalidating snapshot: Error reading/writing."); + else if (err == -ENOMEM) + DMERR("Invalidating snapshot: Unable to allocate exception."); + + if (pe) + remove_exception(&pe->e); + + if (s->store.drop_snapshot) + s->store.drop_snapshot(&s->store); + + s->valid = 0; + + dm_table_event(s->table); +} + static void pending_complete(struct pending_exception *pe, int success) { struct exception *e; @@ -623,50 +652,53 @@ static void pending_complete(struct pending_exception *pe, int success) struct dm_snapshot *s = pe->snap; struct bio *flush = NULL; - if (success) { - e = alloc_exception(); - if (!e) { - DMWARN("Unable to allocate exception."); - down_write(&s->lock); - s->store.drop_snapshot(&s->store); - s->valid = 0; - flush = __flush_bios(pe); - up_write(&s->lock); - - error_bios(bio_list_get(&pe->snapshot_bios)); - goto out; - } - *e = pe->e; - - /* - * Add a proper exception, and remove the - * in-flight exception from the list. - */ + if (!success) { + /* Read/write error - snapshot is unusable */ down_write(&s->lock); - insert_exception(&s->complete, e); - remove_exception(&pe->e); + __invalidate_snapshot(s, pe, -EIO); flush = __flush_bios(pe); - - /* Submit any pending write bios */ up_write(&s->lock); - flush_bios(bio_list_get(&pe->snapshot_bios)); - } else { - /* Read/write error - snapshot is unusable */ + error_snapshot_bios(pe); + goto out; + } + + e = alloc_exception(); + if (!e) { down_write(&s->lock); - if (s->valid) - DMERR("Error reading/writing snapshot"); - s->store.drop_snapshot(&s->store); - s->valid = 0; - remove_exception(&pe->e); + __invalidate_snapshot(s, pe, -ENOMEM); flush = __flush_bios(pe); up_write(&s->lock); - error_bios(bio_list_get(&pe->snapshot_bios)); + error_snapshot_bios(pe); + goto out; + } + *e = pe->e; - dm_table_event(s->table); + /* + * Add a proper exception, and remove the + * in-flight exception from the list. + */ + down_write(&s->lock); + if (!s->valid) { + flush = __flush_bios(pe); + up_write(&s->lock); + + free_exception(e); + + error_snapshot_bios(pe); + goto out; } + insert_exception(&s->complete, e); + remove_exception(&pe->e); + flush = __flush_bios(pe); + + up_write(&s->lock); + + /* Submit any pending write bios */ + flush_bios(bio_list_get(&pe->snapshot_bios)); + out: primary_pe = pe->primary_pe; @@ -758,39 +790,45 @@ __find_pending_exception(struct dm_snapshot *s, struct bio *bio) if (e) { /* cast the exception to a pending exception */ pe = container_of(e, struct pending_exception, e); + goto out; + } - } else { - /* - * Create a new pending exception, we don't want - * to hold the lock while we do this. - */ - up_write(&s->lock); - pe = alloc_pending_exception(); - down_write(&s->lock); + /* + * Create a new pending exception, we don't want + * to hold the lock while we do this. + */ + up_write(&s->lock); + pe = alloc_pending_exception(); + down_write(&s->lock); - e = lookup_exception(&s->pending, chunk); - if (e) { - free_pending_exception(pe); - pe = container_of(e, struct pending_exception, e); - } else { - pe->e.old_chunk = chunk; - bio_list_init(&pe->origin_bios); - bio_list_init(&pe->snapshot_bios); - pe->primary_pe = NULL; - atomic_set(&pe->sibling_count, 1); - pe->snap = s; - pe->started = 0; - - if (s->store.prepare_exception(&s->store, &pe->e)) { - free_pending_exception(pe); - s->valid = 0; - return NULL; - } + if (!s->valid) { + free_pending_exception(pe); + return NULL; + } - insert_exception(&s->pending, &pe->e); - } + e = lookup_exception(&s->pending, chunk); + if (e) { + free_pending_exception(pe); + pe = container_of(e, struct pending_exception, e); + goto out; } + pe->e.old_chunk = chunk; + bio_list_init(&pe->origin_bios); + bio_list_init(&pe->snapshot_bios); + pe->primary_pe = NULL; + atomic_set(&pe->sibling_count, 1); + pe->snap = s; + pe->started = 0; + + if (s->store.prepare_exception(&s->store, &pe->e)) { + free_pending_exception(pe); + return NULL; + } + + insert_exception(&s->pending, &pe->e); + + out: return pe; } @@ -807,13 +845,15 @@ static int snapshot_map(struct dm_target *ti, struct bio *bio, { struct exception *e; struct dm_snapshot *s = (struct dm_snapshot *) ti->private; + int copy_needed = 0; int r = 1; chunk_t chunk; - struct pending_exception *pe; + struct pending_exception *pe = NULL; chunk = sector_to_chunk(s, bio->bi_sector); /* Full snapshots are not usable */ + /* To get here the table must be live so s->active is always set. */ if (!s->valid) return -EIO; @@ -831,36 +871,41 @@ static int snapshot_map(struct dm_target *ti, struct bio *bio, * to copy an exception */ down_write(&s->lock); + if (!s->valid) { + r = -EIO; + goto out_unlock; + } + /* If the block is already remapped - use that, else remap it */ e = lookup_exception(&s->complete, chunk); if (e) { remap_exception(s, e, bio); - up_write(&s->lock); - - } else { - pe = __find_pending_exception(s, bio); - - if (!pe) { - if (s->store.drop_snapshot) - s->store.drop_snapshot(&s->store); - s->valid = 0; - r = -EIO; - up_write(&s->lock); - } else { - remap_exception(s, &pe->e, bio); - bio_list_add(&pe->snapshot_bios, bio); - - if (!pe->started) { - /* this is protected by snap->lock */ - pe->started = 1; - up_write(&s->lock); - start_copy(pe); - } else - up_write(&s->lock); - r = 0; - } + goto out_unlock; + } + + pe = __find_pending_exception(s, bio); + if (!pe) { + __invalidate_snapshot(s, pe, -ENOMEM); + r = -EIO; + goto out_unlock; } + remap_exception(s, &pe->e, bio); + bio_list_add(&pe->snapshot_bios, bio); + + if (!pe->started) { + /* this is protected by snap->lock */ + pe->started = 1; + copy_needed = 1; + } + + r = 0; + + out_unlock: + up_write(&s->lock); + + if (copy_needed) + start_copy(pe); } else { /* * FIXME: this read path scares me because we @@ -872,6 +917,11 @@ static int snapshot_map(struct dm_target *ti, struct bio *bio, /* Do reads */ down_read(&s->lock); + if (!s->valid) { + up_read(&s->lock); + return -EIO; + } + /* See if it it has been remapped */ e = lookup_exception(&s->complete, chunk); if (e) @@ -948,15 +998,15 @@ static int __origin_write(struct list_head *snapshots, struct bio *bio) /* Do all the snapshots on this origin */ list_for_each_entry (snap, snapshots, list) { + down_write(&snap->lock); + /* Only deal with valid and active snapshots */ if (!snap->valid || !snap->active) - continue; + goto next_snapshot; /* Nothing to do if writing beyond end of snapshot */ if (bio->bi_sector >= dm_table_get_size(snap->table)) - continue; - - down_write(&snap->lock); + goto next_snapshot; /* * Remember, different snapshots can have @@ -973,40 +1023,43 @@ static int __origin_write(struct list_head *snapshots, struct bio *bio) * won't destroy the primary_pe while we're inside this loop. */ e = lookup_exception(&snap->complete, chunk); - if (!e) { - pe = __find_pending_exception(snap, bio); - if (!pe) { - snap->store.drop_snapshot(&snap->store); - snap->valid = 0; - - } else { - if (!primary_pe) { - /* - * Either every pe here has same - * primary_pe or none has one yet. - */ - if (pe->primary_pe) - primary_pe = pe->primary_pe; - else { - primary_pe = pe; - first = 1; - } - - bio_list_add(&primary_pe->origin_bios, - bio); - r = 0; - } - if (!pe->primary_pe) { - atomic_inc(&primary_pe->sibling_count); - pe->primary_pe = primary_pe; - } - if (!pe->started) { - pe->started = 1; - list_add_tail(&pe->list, &pe_queue); - } + if (e) + goto next_snapshot; + + pe = __find_pending_exception(snap, bio); + if (!pe) { + __invalidate_snapshot(snap, pe, ENOMEM); + goto next_snapshot; + } + + if (!primary_pe) { + /* + * Either every pe here has same + * primary_pe or none has one yet. + */ + if (pe->primary_pe) + primary_pe = pe->primary_pe; + else { + primary_pe = pe; + first = 1; } + + bio_list_add(&primary_pe->origin_bios, bio); + + r = 0; + } + + if (!pe->primary_pe) { + atomic_inc(&primary_pe->sibling_count); + pe->primary_pe = primary_pe; + } + + if (!pe->started) { + pe->started = 1; + list_add_tail(&pe->list, &pe_queue); } + next_snapshot: up_write(&snap->lock); } |