diff options
| -rw-r--r-- | Documentation/device-mapper/snapshot.txt | 10 | ||||
| -rw-r--r-- | drivers/md/dm-exception-store.c | 6 | ||||
| -rw-r--r-- | drivers/md/dm-exception-store.h | 5 | ||||
| -rw-r--r-- | drivers/md/dm-snap-persistent.c | 17 | ||||
| -rw-r--r-- | drivers/md/dm-snap-transient.c | 3 | ||||
| -rw-r--r-- | drivers/md/dm-snap.c | 14 |
6 files changed, 37 insertions, 18 deletions
diff --git a/Documentation/device-mapper/snapshot.txt b/Documentation/device-mapper/snapshot.txt index 0d5bc46dc167..ad6949bff2e3 100644 --- a/Documentation/device-mapper/snapshot.txt +++ b/Documentation/device-mapper/snapshot.txt @@ -41,9 +41,13 @@ useless and be disabled, returning errors. So it is important to monitor the amount of free space and expand the <COW device> before it fills up. <persistent?> is P (Persistent) or N (Not persistent - will not survive -after reboot). -The difference is that for transient snapshots less metadata must be -saved on disk - they can be kept in memory by the kernel. +after reboot). O (Overflow) can be added as a persistent store option +to allow userspace to advertise its support for seeing "Overflow" in the +snapshot status. So supported store types are "P", "PO" and "N". + +The difference between persistent and transient is with transient +snapshots less metadata must be saved on disk - they can be kept in +memory by the kernel. * snapshot-merge <origin> <COW device> <persistent> <chunksize> diff --git a/drivers/md/dm-exception-store.c b/drivers/md/dm-exception-store.c index ebaa4f803eec..192bb8beeb6b 100644 --- a/drivers/md/dm-exception-store.c +++ b/drivers/md/dm-exception-store.c @@ -203,7 +203,7 @@ int dm_exception_store_create(struct dm_target *ti, int argc, char **argv, return -EINVAL; } - tmp_store = kmalloc(sizeof(*tmp_store), GFP_KERNEL); + tmp_store = kzalloc(sizeof(*tmp_store), GFP_KERNEL); if (!tmp_store) { ti->error = "Exception store allocation failed"; return -ENOMEM; @@ -215,7 +215,7 @@ int dm_exception_store_create(struct dm_target *ti, int argc, char **argv, else if (persistent == 'N') type = get_type("N"); else { - ti->error = "Persistent flag is not P or N"; + ti->error = "Exception store type is not P or N"; r = -EINVAL; goto bad_type; } @@ -233,7 +233,7 @@ int dm_exception_store_create(struct dm_target *ti, int argc, char **argv, if (r) goto bad; - r = type->ctr(tmp_store, 0, NULL); + r = type->ctr(tmp_store, (strlen(argv[0]) > 1 ? &argv[0][1] : NULL)); if (r) { ti->error = "Exception store type constructor failed"; goto bad; diff --git a/drivers/md/dm-exception-store.h b/drivers/md/dm-exception-store.h index 0b2536247cf5..fae34e7a0b1e 100644 --- a/drivers/md/dm-exception-store.h +++ b/drivers/md/dm-exception-store.h @@ -42,8 +42,7 @@ struct dm_exception_store_type { const char *name; struct module *module; - int (*ctr) (struct dm_exception_store *store, - unsigned argc, char **argv); + int (*ctr) (struct dm_exception_store *store, char *options); /* * Destroys this object when you've finished with it. @@ -123,6 +122,8 @@ struct dm_exception_store { unsigned chunk_shift; void *context; + + bool userspace_supports_overflow; }; /* diff --git a/drivers/md/dm-snap-persistent.c b/drivers/md/dm-snap-persistent.c index bf71583296f7..aeacad9be51d 100644 --- a/drivers/md/dm-snap-persistent.c +++ b/drivers/md/dm-snap-persistent.c @@ -7,6 +7,7 @@ #include "dm-exception-store.h" +#include <linux/ctype.h> #include <linux/mm.h> #include <linux/pagemap.h> #include <linux/vmalloc.h> @@ -843,8 +844,7 @@ static void persistent_drop_snapshot(struct dm_exception_store *store) DMWARN("write header failed"); } -static int persistent_ctr(struct dm_exception_store *store, - unsigned argc, char **argv) +static int persistent_ctr(struct dm_exception_store *store, char *options) { struct pstore *ps; @@ -873,6 +873,16 @@ static int persistent_ctr(struct dm_exception_store *store, return -ENOMEM; } + if (options) { + char overflow = toupper(options[0]); + if (overflow == 'O') + store->userspace_supports_overflow = true; + else { + DMERR("Unsupported persistent store option: %s", options); + return -EINVAL; + } + } + store->context = ps; return 0; @@ -888,7 +898,8 @@ static unsigned persistent_status(struct dm_exception_store *store, case STATUSTYPE_INFO: break; case STATUSTYPE_TABLE: - DMEMIT(" P %llu", (unsigned long long)store->chunk_size); + DMEMIT(" %s %llu", store->userspace_supports_overflow ? "PO" : "P", + (unsigned long long)store->chunk_size); } return sz; diff --git a/drivers/md/dm-snap-transient.c b/drivers/md/dm-snap-transient.c index 1ce9a2586e41..9b7c8c8049d6 100644 --- a/drivers/md/dm-snap-transient.c +++ b/drivers/md/dm-snap-transient.c @@ -70,8 +70,7 @@ static void transient_usage(struct dm_exception_store *store, *metadata_sectors = 0; } -static int transient_ctr(struct dm_exception_store *store, - unsigned argc, char **argv) +static int transient_ctr(struct dm_exception_store *store, char *options) { struct transient_c *tc; diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c index c0bcd6516dfe..c06b74e91cd6 100644 --- a/drivers/md/dm-snap.c +++ b/drivers/md/dm-snap.c @@ -1098,7 +1098,7 @@ static void stop_merge(struct dm_snapshot *s) } /* - * Construct a snapshot mapping: <origin_dev> <COW-dev> <p/n> <chunk-size> + * Construct a snapshot mapping: <origin_dev> <COW-dev> <p|po|n> <chunk-size> */ static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv) { @@ -1302,6 +1302,7 @@ static void __handover_exceptions(struct dm_snapshot *snap_src, u.store_swap = snap_dest->store; snap_dest->store = snap_src->store; + snap_dest->store->userspace_supports_overflow = u.store_swap->userspace_supports_overflow; snap_src->store = u.store_swap; snap_dest->store->snap = snap_dest; @@ -1739,8 +1740,11 @@ static int snapshot_map(struct dm_target *ti, struct bio *bio) pe = __find_pending_exception(s, pe, chunk); if (!pe) { - s->snapshot_overflowed = 1; - DMERR("Snapshot overflowed: Unable to allocate exception."); + if (s->store->userspace_supports_overflow) { + s->snapshot_overflowed = 1; + DMERR("Snapshot overflowed: Unable to allocate exception."); + } else + __invalidate_snapshot(s, -ENOMEM); r = -EIO; goto out_unlock; } @@ -2365,7 +2369,7 @@ static struct target_type origin_target = { static struct target_type snapshot_target = { .name = "snapshot", - .version = {1, 14, 0}, + .version = {1, 15, 0}, .module = THIS_MODULE, .ctr = snapshot_ctr, .dtr = snapshot_dtr, @@ -2379,7 +2383,7 @@ static struct target_type snapshot_target = { static struct target_type merge_target = { .name = dm_snapshot_merge_target_name, - .version = {1, 3, 0}, + .version = {1, 4, 0}, .module = THIS_MODULE, .ctr = snapshot_ctr, .dtr = snapshot_dtr, |