2 files changed, 45 insertions, 26 deletions

diff --git a/drivers/md/dm-exception-store.c b/drivers/md/dm-exception-store.c
index cc07bbebbb16..34a75939a0ca 100644
--- a/drivers/md/dm-exception-store.c
+++ b/drivers/md/dm-exception-store.c
@@ -91,7 +91,6 @@ struct pstore {
         struct dm_snapshot *snap;       /* up pointer to my snapshot */
         int version;
         int valid;
-        uint32_t chunk_size;
         uint32_t exceptions_per_area;
 
         /*
@@ -133,7 +132,7 @@ static int alloc_area(struct pstore *ps)
         int r = -ENOMEM;
         size_t len;
 
-        len = ps->chunk_size << SECTOR_SHIFT;
+        len = ps->snap->chunk_size << SECTOR_SHIFT;
 
         /*
          * Allocate the chunk_size block of memory that will hold
@@ -160,8 +159,8 @@ static int chunk_io(struct pstore *ps, uint32_t chunk, int rw)
         unsigned long bits;
 
         where.bdev = ps->snap->cow->bdev;
-        where.sector = ps->chunk_size * chunk;
-        where.count = ps->chunk_size;
+        where.sector = ps->snap->chunk_size * chunk;
+        where.count = ps->snap->chunk_size;
 
         return dm_io_sync_vm(1, &where, rw, ps->area, &bits);
 }
@@ -188,7 +187,7 @@ static int area_io(struct pstore *ps, uint32_t area, int rw)
 
 static int zero_area(struct pstore *ps, uint32_t area)
 {
-        memset(ps->area, 0, ps->chunk_size << SECTOR_SHIFT);
+        memset(ps->area, 0, ps->snap->chunk_size << SECTOR_SHIFT);
         return area_io(ps, area, WRITE);
 }
 
@@ -196,6 +195,7 @@ static int read_header(struct pstore *ps, int *new_snapshot)
 {
         int r;
         struct disk_header *dh;
+        chunk_t chunk_size;
 
         r = chunk_io(ps, 0, READ);
         if (r)
@@ -210,8 +210,29 @@ static int read_header(struct pstore *ps, int *new_snapshot)
                 *new_snapshot = 0;
                 ps->valid = le32_to_cpu(dh->valid);
                 ps->version = le32_to_cpu(dh->version);
-                ps->chunk_size = le32_to_cpu(dh->chunk_size);
-
+                chunk_size = le32_to_cpu(dh->chunk_size);
+                if (ps->snap->chunk_size != chunk_size) {
+                        DMWARN("chunk size %llu in device metadata overrides "
+                               "table chunk size of %llu.",
+                               (unsigned long long)chunk_size,
+                               (unsigned long long)ps->snap->chunk_size);
+
+                        /* We had a bogus chunk_size. Fix stuff up. */
+                        dm_io_put(sectors_to_pages(ps->snap->chunk_size));
+                        free_area(ps);
+
+                        ps->snap->chunk_size = chunk_size;
+                        ps->snap->chunk_mask = chunk_size - 1;
+                        ps->snap->chunk_shift = ffs(chunk_size) - 1;
+
+                        r = alloc_area(ps);
+                        if (r)
+                                return r;
+
+                        r = dm_io_get(sectors_to_pages(chunk_size));
+                        if (r)
+                                return r;
+                }
         } else {
                 DMWARN("Invalid/corrupt snapshot");
                 r = -ENXIO;
@@ -224,13 +245,13 @@ static int write_header(struct pstore *ps)
 {
         struct disk_header *dh;
 
-        memset(ps->area, 0, ps->chunk_size << SECTOR_SHIFT);
+        memset(ps->area, 0, ps->snap->chunk_size << SECTOR_SHIFT);
 
         dh = (struct disk_header *) ps->area;
         dh->magic = cpu_to_le32(SNAP_MAGIC);
         dh->valid = cpu_to_le32(ps->valid);
         dh->version = cpu_to_le32(ps->version);
-        dh->chunk_size = cpu_to_le32(ps->chunk_size);
+        dh->chunk_size = cpu_to_le32(ps->snap->chunk_size);
 
         return chunk_io(ps, 0, WRITE);
 }
@@ -365,7 +386,7 @@ static void persistent_destroy(struct exception_store *store)
 {
         struct pstore *ps = get_info(store);
 
-        dm_io_put(sectors_to_pages(ps->chunk_size));
+        dm_io_put(sectors_to_pages(ps->snap->chunk_size));
         vfree(ps->callbacks);
         free_area(ps);
         kfree(ps);
@@ -384,6 +405,16 @@ static int persistent_read_metadata(struct exception_store *store)
                 return r;
 
         /*
+         * Now we know correct chunk_size, complete the initialisation.
+         */
+        ps->exceptions_per_area = (ps->snap->chunk_size << SECTOR_SHIFT) /
+                                  sizeof(struct disk_exception);
+        ps->callbacks = dm_vcalloc(ps->exceptions_per_area,
+                        sizeof(*ps->callbacks));
+        if (!ps->callbacks)
+                return -ENOMEM;
+
+        /*
          * Do we need to setup a new snapshot ?
          */
         if (new_snapshot) {
@@ -533,9 +564,6 @@ int dm_create_persistent(struct exception_store *store, uint32_t chunk_size)
         ps->snap = store->snap;
         ps->valid = 1;
         ps->version = SNAPSHOT_DISK_VERSION;
-        ps->chunk_size = chunk_size;
-        ps->exceptions_per_area = (chunk_size << SECTOR_SHIFT) /
-            sizeof(struct disk_exception);
         ps->next_free = 2;      /* skipping the header and first area */
         ps->current_committed = 0;
 
@@ -543,18 +571,9 @@ int dm_create_persistent(struct exception_store *store, uint32_t chunk_size)
         if (r)
                 goto bad;
 
-        /*
-         * Allocate space for all the callbacks.
-         */
         ps->callback_count = 0;
         atomic_set(&ps->pending_count, 0);
-        ps->callbacks = dm_vcalloc(ps->exceptions_per_area,
-                                   sizeof(*ps->callbacks));
-
-        if (!ps->callbacks) {
-                r = -ENOMEM;
-                goto bad;
-        }
+        ps->callbacks = NULL;
 
         store->destroy = persistent_destroy;
         store->read_metadata = persistent_read_metadata;
diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c
index 08312b46463a..b84bc1aae353 100644
--- a/drivers/md/dm-snap.c
+++ b/drivers/md/dm-snap.c
@@ -530,7 +530,7 @@ static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv)
         }
 
         ti->private = s;
-        ti->split_io = chunk_size;
+        ti->split_io = s->chunk_size;
 
         return 0;
 
@@ -1204,7 +1204,7 @@ static int origin_status(struct dm_target *ti, status_type_t type, char *result,
 
 static struct target_type origin_target = {
         .name    = "snapshot-origin",
-        .version = {1, 1, 0},
+        .version = {1, 4, 0},
         .module  = THIS_MODULE,
         .ctr     = origin_ctr,
         .dtr     = origin_dtr,
@@ -1215,7 +1215,7 @@ static struct target_type origin_target = {
 
 static struct target_type snapshot_target = {
         .name    = "snapshot",
-        .version = {1, 1, 0},
+        .version = {1, 4, 0},
         .module  = THIS_MODULE,
         .ctr     = snapshot_ctr,
         .dtr     = snapshot_dtr,