Patch name: dm-exception-store-generalize-table-args.patch

From: Jonthan Brassow <jbrassow@redhat.com>

Rework 'dm_exception_store_create' arguments to make way for
cleaner interface when new constructor table format is
introduced.

[FIXME better /* comment */, don't use bad0, write full patch description, why buf[8]? ]
Signed-off-by: Jonthan Brassow <jbrassow@redhat.com>

---
drivers/md/dm-exception-store.c | 33 +++++++++++++-----------
drivers/md/dm-exception-store.h | 4 +--
drivers/md/dm-snap.c | 53 ++++++++++++++++++++++++++++++++++------
3 files changed, 66 insertions(+), 24 deletions(-)

Index: linux-2.6.29/drivers/md/dm-exception-store.c
================================================== =================
--- linux-2.6.29.orig/drivers/md/dm-exception-store.c
+++ linux-2.6.29/drivers/md/dm-exception-store.c
@@ -190,16 +190,15 @@ static int set_chunk_size(struct dm_exce
return 0;
}

-int dm_exception_store_create(struct dm_target *ti, int argc, char **argv,
- unsigned *args_used,
+int dm_exception_store_create(const char *type_name, struct dm_target *ti,
+ int argc, char **argv,
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) {
+ if (argc < 2) {
ti->error = "Insufficient exception store arguments";
return -EINVAL;
}
@@ -210,13 +209,7 @@ int dm_exception_store_create(struct dm_
return -ENOMEM;
}

- 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]);
+ type = get_type(type_name);
if (!type) {
ti->error = "Exception store type not recognised";
r = -EINVAL;
@@ -226,6 +219,12 @@ int dm_exception_store_create(struct dm_
tmp_store->type = type;
tmp_store->ti = ti;

+ /*
+ * COW-dev and chunk_size are common to all types of
+ * exception stores and are stored directly in the
+ * dm_exception_store and not passed on to the
+ * constructor for the dm_exception_store_type
+ */
r = dm_get_device(ti, argv[0], 0, 0,
FMODE_READ | FMODE_WRITE, &tmp_store->cow);
if (r) {
@@ -233,17 +232,21 @@ int dm_exception_store_create(struct dm_
goto bad_cow;
}

- r = set_chunk_size(tmp_store, argv[2], &ti->error);
- if (r)
+ r = set_chunk_size(tmp_store, argv[1], &ti->error);
+ if (r) {
+ ti->error = "Unable to set chunk size";
goto bad_cow;
+ }
+
+ argc -= 2;
+ argv += 2;

- r = type->ctr(tmp_store, 0, NULL);
+ r = type->ctr(tmp_store, argc, argv);
if (r) {
ti->error = "Exception store type constructor failed";
goto bad_ctr;
}

- *args_used = 3;
*store = tmp_store;
return 0;

Index: linux-2.6.29/drivers/md/dm-exception-store.h
================================================== =================
--- linux-2.6.29.orig/drivers/md/dm-exception-store.h
+++ linux-2.6.29/drivers/md/dm-exception-store.h
@@ -168,8 +168,8 @@ static inline chunk_t sector_to_chunk(st
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(struct dm_target *ti, int argc, char **argv,
- unsigned *args_used,
+int dm_exception_store_create(const char *type_name, struct dm_target *ti,
+ int argc, char **argv,
struct dm_exception_store **store);
void dm_exception_store_destroy(struct dm_exception_store *store);

Index: linux-2.6.29/drivers/md/dm-snap.c
================================================== =================
--- linux-2.6.29.orig/drivers/md/dm-snap.c
+++ linux-2.6.29/drivers/md/dm-snap.c
@@ -7,6 +7,7 @@
*/

#include <linux/blkdev.h>
+#include <linux/ctype.h>
#include <linux/device-mapper.h>
#include <linux/delay.h>
#include <linux/fs.h>
@@ -571,6 +572,45 @@ static int init_hash_tables(struct dm_sn
}

/*
+ * create_exception_store
+ * @ti
+ * @argc
+ * @argv
+ * @args_used
+ * @store: contains newly allocated dm_exception_store
+ *
+ * Possible formats for argv::
+ * <COW-dev> p/n <chunk-size>
+ *
+ * Returns: 0 on success, -Exxx on error
+ */
+static int create_exception_store(struct dm_target *ti, unsigned argc,
+ char **argv, unsigned *args_used,
+ struct dm_exception_store **store)
+{
+ char *tmp_argv[2];
+ char buf[8];
+
+ *store = NULL;
+
+ if (1 /* less change patch to patch */) {
+ if (argc < 3) {
+ ti->error = "Insufficient exception store arguments";
+ return -EINVAL;
+ }
+
+ tmp_argv[0] = argv[0]; /* COW dev */
+ tmp_argv[1] = argv[2]; /* chunk size */
+
+ *args_used = 3;
+ buf[0] = toupper(*argv[1]);
+ buf[1] = '';
+
+ return dm_exception_store_create(buf, ti, 2, tmp_argv, store);
+ }
+}
+
+/*
* 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)
@@ -592,12 +632,9 @@ static int snapshot_ctr(struct dm_target
argv++;
argc--;

- r = dm_exception_store_create(ti, argc, argv, &args_used, &store);
- if (r) {
- ti->error = "Couldn't create exception store";
- r = -EINVAL;
- goto bad_args;
- }
+ r = create_exception_store(ti, argc, argv, &args_used, &store);
+ if (r)
+ return r;

argv += args_used;
argc -= args_used;
@@ -1436,7 +1473,7 @@ static int __init dm_snapshot_init(void)
r = dm_register_target(&snapshot_target);
if (r) {
DMERR("snapshot target register failed %d", r);
- return r;
+ goto bad0;
}

r = dm_register_target(&origin_target);
@@ -1493,6 +1530,8 @@ bad2:
dm_unregister_target(&origin_target);
bad1:
dm_unregister_target(&snapshot_target);
+bad0:
+ dm_exception_store_exit();
return r;
}


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