dm snapshot: move ctr parsing to exception store
Jonathan Brassow [Thu, 2 Apr 2009 18:55:34 +0000 (19:55 +0100)]
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>

drivers/md/dm-exception-store.c
drivers/md/dm-exception-store.h
drivers/md/dm-snap.c

index 2078b92..a2e26c2 100644 (file)
@@ -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 @@ int dm_exception_store_type_unregister(struct dm_exception_store_type *type)
 }
 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);
 }
index 835f402..023a707 100644 (file)
@@ -167,9 +167,8 @@ static inline chunk_t sector_to_chunk(struct dm_exception_store *store,
 int dm_exception_store_type_register(struct dm_exception_store_type *type);
 int dm_exception_store_type_unregister(struct dm_exception_store_type *type);
 
-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,
+int dm_exception_store_create(struct dm_target *ti, int argc, char **argv,
+                             unsigned *args_used,
                              struct dm_exception_store **store);
 void dm_exception_store_destroy(struct dm_exception_store *store);
 
index fcb1ac1..974916b 100644 (file)
@@ -7,7 +7,6 @@
  */
 
 #include <linux/blkdev.h>
-#include <linux/ctype.h>
 #include <linux/device-mapper.h>
 #include <linux/delay.h>
 #include <linux/fs.h>
@@ -538,8 +537,7 @@ static int calc_max_buckets(void)
 /*
  * Allocate room for a suitable hash table.
  */
-static int init_hash_tables(struct dm_snapshot *s, chunk_t chunk_shift,
-                           struct dm_dev *cow)
+static int init_hash_tables(struct dm_snapshot *s)
 {
        sector_t hash_size, cow_dev_size, origin_dev_size, max_buckets;
 
@@ -547,11 +545,11 @@ static int init_hash_tables(struct dm_snapshot *s, chunk_t chunk_shift,
         * Calculate based on the size of the original volume or
         * the COW volume...
         */
-       cow_dev_size = get_dev_size(cow->bdev);
+       cow_dev_size = get_dev_size(s->store->cow->bdev);
        origin_dev_size = get_dev_size(s->origin->bdev);
        max_buckets = calc_max_buckets();
 
-       hash_size = min(origin_dev_size, cow_dev_size) >> chunk_shift;
+       hash_size = min(origin_dev_size, cow_dev_size) >> s->store->chunk_shift;
        hash_size = min(hash_size, max_buckets);
 
        hash_size = rounddown_pow_of_two(hash_size);
@@ -576,60 +574,6 @@ static int init_hash_tables(struct dm_snapshot *s, chunk_t chunk_shift,
 }
 
 /*
- * 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_snapshot *s, const char *chunk_size_arg,
-                         chunk_t *chunk_size, chunk_t *chunk_mask,
-                         chunk_t *chunk_shift, struct dm_dev *cow,
-                         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) {
-               *chunk_size = *chunk_mask = *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(cow->bdev) >> 9)) {
-               *error = "Chunk size is not a multiple of device blocksize";
-               return -EINVAL;
-       }
-
-       *chunk_size = chunk_size_ulong;
-       *chunk_mask = chunk_size_ulong - 1;
-       *chunk_shift = ffs(chunk_size_ulong) - 1;
-
-       return 0;
-}
-
-/*
  * Construct a snapshot mapping: <origin_dev> <COW-dev> <p/n> <chunk-size>
  */
 static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv)
@@ -637,55 +581,45 @@ static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv)
        struct dm_snapshot *s;
        int i;
        int r = -EINVAL;
-       char persistent;
        char *origin_path;
-       char *cow_path;
-       chunk_t chunk_size, chunk_mask, chunk_shift;
-       struct dm_dev *cow;
+       struct dm_exception_store *store;
+       unsigned args_used;
 
        if (argc != 4) {
                ti->error = "requires exactly 4 arguments";
                r = -EINVAL;
-               goto bad1;
+               goto bad_args;
        }
 
        origin_path = argv[0];
-       cow_path = argv[1];
-       persistent = toupper(*argv[2]);
+       argv++;
+       argc--;
 
-       if (persistent != 'P' && persistent != 'N') {
-               ti->error = "Persistent flag is not P or N";
+       r = dm_exception_store_create(ti, argc, argv, &args_used, &store);
+       if (r) {
+               ti->error = "Couldn't create exception store";
                r = -EINVAL;
-               goto bad1;
+               goto bad_args;
        }
 
+       argv += args_used;
+       argc -= args_used;
+
        s = kmalloc(sizeof(*s), GFP_KERNEL);
-       if (s == NULL) {
+       if (!s) {
                ti->error = "Cannot allocate snapshot context private "
                    "structure";
                r = -ENOMEM;
-               goto bad1;
+               goto bad_snap;
        }
 
        r = dm_get_device(ti, origin_path, 0, ti->len, FMODE_READ, &s->origin);
        if (r) {
                ti->error = "Cannot get origin device";
-               goto bad2;
+               goto bad_origin;
        }
 
-       r = dm_get_device(ti, cow_path, 0, 0,
-                         FMODE_READ | FMODE_WRITE, &cow);
-       if (r) {
-               dm_put_device(ti, s->origin);
-               ti->error = "Cannot get COW device";
-               goto bad2;
-       }
-
-       r = set_chunk_size(s, argv[3], &chunk_size, &chunk_mask, &chunk_shift,
-                          cow, &ti->error);
-       if (r)
-               goto bad3;
-
+       s->store = store;
        s->valid = 1;
        s->active = 0;
        atomic_set(&s->pending_exceptions_count, 0);
@@ -693,30 +627,22 @@ static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv)
        spin_lock_init(&s->pe_lock);
 
        /* Allocate hash table for COW data */
-       if (init_hash_tables(s, chunk_shift, cow)) {
+       if (init_hash_tables(s)) {
                ti->error = "Unable to allocate hash table space";
                r = -ENOMEM;
-               goto bad3;
-       }
-
-       r = dm_exception_store_create(argv[2], ti, chunk_size, chunk_mask,
-                                     chunk_shift, cow, &s->store);
-       if (r) {
-               ti->error = "Couldn't create exception store";
-               r = -EINVAL;
-               goto bad4;
+               goto bad_hash_tables;
        }
 
        r = dm_kcopyd_client_create(SNAPSHOT_PAGES, &s->kcopyd_client);
        if (r) {
                ti->error = "Could not create kcopyd client";
-               goto bad5;
+               goto bad_kcopyd;
        }
 
        s->pending_pool = mempool_create_slab_pool(MIN_IOS, pending_cache);
        if (!s->pending_pool) {
                ti->error = "Could not allocate mempool for pending exceptions";
-               goto bad6;
+               goto bad_pending_pool;
        }
 
        s->tracked_chunk_pool = mempool_create_slab_pool(MIN_IOS,
@@ -759,30 +685,29 @@ static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 
        return 0;
 
- bad_load_and_register:
+bad_load_and_register:
        mempool_destroy(s->tracked_chunk_pool);
 
- bad_tracked_chunk_pool:
+bad_tracked_chunk_pool:
        mempool_destroy(s->pending_pool);
 
- bad6:
+bad_pending_pool:
        dm_kcopyd_client_destroy(s->kcopyd_client);
 
- bad5:
-       s->store->type->dtr(s->store);
-
- bad4:
+bad_kcopyd:
        exit_exception_table(&s->pending, pending_cache);
        exit_exception_table(&s->complete, exception_cache);
 
- bad3:
-       dm_put_device(ti, cow);
+bad_hash_tables:
        dm_put_device(ti, s->origin);
 
- bad2:
+bad_origin:
        kfree(s);
 
- bad1:
+bad_snap:
+       dm_exception_store_destroy(store);
+
+bad_args:
        return r;
 }
 
@@ -793,8 +718,6 @@ static void __free_exceptions(struct dm_snapshot *s)
 
        exit_exception_table(&s->pending, pending_cache);
        exit_exception_table(&s->complete, exception_cache);
-
-       s->store->type->dtr(s->store);
 }
 
 static void snapshot_dtr(struct dm_target *ti)
@@ -803,7 +726,6 @@ static void snapshot_dtr(struct dm_target *ti)
        int i;
 #endif
        struct dm_snapshot *s = ti->private;
-       struct dm_dev *cow = s->store->cow;
 
        flush_workqueue(ksnapd);
 
@@ -831,7 +753,8 @@ static void snapshot_dtr(struct dm_target *ti)
        mempool_destroy(s->pending_pool);
 
        dm_put_device(ti, s->origin);
-       dm_put_device(ti, cow);
+
+       dm_exception_store_destroy(s->store);
 
        kfree(s);
 }