dm snapshot: test chunk size against both origin and snapshot
Validate chunk size against both origin and snapshot sector size
Don't allow chunk size smaller than either origin or snapshot logical
sector size. Reading or writing data not aligned to sector size is not
allowed and causes immediate errors.
This requires us to open the origin before initialising the
exception store and to export dm_snap_origin.
Cc: stable@kernel.org
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
diff --git a/drivers/md/dm-exception-store.c b/drivers/md/dm-exception-store.c
index 2b7907b..0bdb201 100644
--- a/drivers/md/dm-exception-store.c
+++ b/drivers/md/dm-exception-store.c
@@ -173,7 +173,9 @@
/* Validate the chunk size against the device block size */
if (chunk_size %
- (bdev_logical_block_size(dm_snap_cow(store->snap)->bdev) >> 9)) {
+ (bdev_logical_block_size(dm_snap_cow(store->snap)->bdev) >> 9) ||
+ chunk_size %
+ (bdev_logical_block_size(dm_snap_origin(store->snap)->bdev) >> 9)) {
*error = "Chunk size is not a multiple of device blocksize";
return -EINVAL;
}
diff --git a/drivers/md/dm-exception-store.h b/drivers/md/dm-exception-store.h
index e8dfa06..0b25362 100644
--- a/drivers/md/dm-exception-store.h
+++ b/drivers/md/dm-exception-store.h
@@ -126,8 +126,9 @@
};
/*
- * Obtain the cow device used by a given snapshot.
+ * Obtain the origin or cow device used by a given snapshot.
*/
+struct dm_dev *dm_snap_origin(struct dm_snapshot *snap);
struct dm_dev *dm_snap_cow(struct dm_snapshot *snap);
/*
diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c
index a6ab989..a1f2ab5 100644
--- a/drivers/md/dm-snap.c
+++ b/drivers/md/dm-snap.c
@@ -148,6 +148,12 @@
#define RUNNING_MERGE 0
#define SHUTDOWN_MERGE 1
+struct dm_dev *dm_snap_origin(struct dm_snapshot *s)
+{
+ return s->origin;
+}
+EXPORT_SYMBOL(dm_snap_origin);
+
struct dm_dev *dm_snap_cow(struct dm_snapshot *s)
{
return s->cow;
@@ -1065,10 +1071,6 @@
origin_mode = FMODE_WRITE;
}
- origin_path = argv[0];
- argv++;
- argc--;
-
s = kmalloc(sizeof(*s), GFP_KERNEL);
if (!s) {
ti->error = "Cannot allocate snapshot context private "
@@ -1077,6 +1079,16 @@
goto bad;
}
+ origin_path = argv[0];
+ argv++;
+ argc--;
+
+ r = dm_get_device(ti, origin_path, origin_mode, &s->origin);
+ if (r) {
+ ti->error = "Cannot get origin device";
+ goto bad_origin;
+ }
+
cow_path = argv[0];
argv++;
argc--;
@@ -1097,12 +1109,6 @@
argv += args_used;
argc -= args_used;
- r = dm_get_device(ti, origin_path, origin_mode, &s->origin);
- if (r) {
- ti->error = "Cannot get origin device";
- goto bad_origin;
- }
-
s->ti = ti;
s->valid = 1;
s->active = 0;
@@ -1212,15 +1218,15 @@
dm_exception_table_exit(&s->complete, exception_cache);
bad_hash_tables:
- dm_put_device(ti, s->origin);
-
-bad_origin:
dm_exception_store_destroy(s->store);
bad_store:
dm_put_device(ti, s->cow);
bad_cow:
+ dm_put_device(ti, s->origin);
+
+bad_origin:
kfree(s);
bad:
@@ -1314,12 +1320,12 @@
mempool_destroy(s->pending_pool);
- dm_put_device(ti, s->origin);
-
dm_exception_store_destroy(s->store);
dm_put_device(ti, s->cow);
+ dm_put_device(ti, s->origin);
+
kfree(s);
}