dm snapshot: move ctr parsing to exception store
First step of having the exception stores parse their own arguments -
generalizing the interface.
Signed-off-by: Jonathan Brassow <jbrassow@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 2078b92..a2e26c2 100644
--- a/drivers/md/dm-exception-store.c
+++ b/drivers/md/dm-exception-store.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>
@@ -137,49 +138,129 @@
}
EXPORT_SYMBOL(dm_exception_store_type_unregister);
-int dm_exception_store_create(const char *type_name, struct dm_target *ti,
- chunk_t chunk_size, chunk_t chunk_mask,
- chunk_t chunk_shift, struct dm_dev *cow,
+/*
+ * Round a number up to the nearest 'size' boundary. size must
+ * be a power of 2.
+ */
+static ulong round_up(ulong n, ulong size)
+{
+ size--;
+ return (n + size) & ~size;
+}
+
+static int set_chunk_size(struct dm_exception_store *store,
+ const char *chunk_size_arg, char **error)
+{
+ unsigned long chunk_size_ulong;
+ char *value;
+
+ chunk_size_ulong = simple_strtoul(chunk_size_arg, &value, 10);
+ if (*chunk_size_arg == '\0' || *value != '\0') {
+ *error = "Invalid chunk size";
+ return -EINVAL;
+ }
+
+ if (!chunk_size_ulong) {
+ store->chunk_size = store->chunk_mask = store->chunk_shift = 0;
+ return 0;
+ }
+
+ /*
+ * Chunk size must be multiple of page size. Silently
+ * round up if it's not.
+ */
+ chunk_size_ulong = round_up(chunk_size_ulong, PAGE_SIZE >> 9);
+
+ /* Check chunk_size is a power of 2 */
+ if (!is_power_of_2(chunk_size_ulong)) {
+ *error = "Chunk size is not a power of 2";
+ return -EINVAL;
+ }
+
+ /* Validate the chunk size against the device block size */
+ if (chunk_size_ulong % (bdev_hardsect_size(store->cow->bdev) >> 9)) {
+ *error = "Chunk size is not a multiple of device blocksize";
+ return -EINVAL;
+ }
+
+ store->chunk_size = chunk_size_ulong;
+ store->chunk_mask = chunk_size_ulong - 1;
+ store->chunk_shift = ffs(chunk_size_ulong) - 1;
+
+ return 0;
+}
+
+int dm_exception_store_create(struct dm_target *ti, int argc, char **argv,
+ unsigned *args_used,
struct dm_exception_store **store)
{
int r = 0;
struct dm_exception_store_type *type;
struct dm_exception_store *tmp_store;
+ char persistent;
+
+ if (argc < 3) {
+ ti->error = "Insufficient exception store arguments";
+ return -EINVAL;
+ }
tmp_store = kmalloc(sizeof(*tmp_store), GFP_KERNEL);
- if (!tmp_store)
+ if (!tmp_store) {
+ ti->error = "Exception store allocation failed";
return -ENOMEM;
+ }
- type = get_type(type_name);
- if (!type) {
- kfree(tmp_store);
+ persistent = toupper(*argv[1]);
+ if (persistent != 'P' && persistent != 'N') {
+ ti->error = "Persistent flag is not P or N";
return -EINVAL;
}
+ type = get_type(argv[1]);
+ if (!type) {
+ ti->error = "Exception store type not recognised";
+ r = -EINVAL;
+ goto bad_type;
+ }
+
tmp_store->type = type;
tmp_store->ti = ti;
- tmp_store->chunk_size = chunk_size;
- tmp_store->chunk_mask = chunk_mask;
- tmp_store->chunk_shift = chunk_shift;
+ r = dm_get_device(ti, argv[0], 0, 0,
+ FMODE_READ | FMODE_WRITE, &tmp_store->cow);
+ if (r) {
+ ti->error = "Cannot get COW device";
+ goto bad_cow;
+ }
- tmp_store->cow = cow;
+ r = set_chunk_size(tmp_store, argv[2], &ti->error);
+ if (r)
+ goto bad_cow;
r = type->ctr(tmp_store, 0, NULL);
if (r) {
- put_type(type);
- kfree(tmp_store);
- return r;
+ ti->error = "Exception store type constructor failed";
+ goto bad_ctr;
}
+ *args_used = 3;
*store = tmp_store;
return 0;
+
+bad_ctr:
+ dm_put_device(ti, tmp_store->cow);
+bad_cow:
+ put_type(type);
+bad_type:
+ kfree(tmp_store);
+ return r;
}
EXPORT_SYMBOL(dm_exception_store_create);
void dm_exception_store_destroy(struct dm_exception_store *store)
{
store->type->dtr(store);
+ dm_put_device(store->ti, store->cow);
put_type(store->type);
kfree(store);
}