Re: [PATCH] Make it possible to set a uuid if one was not set during DM_DEV_CREATE.

[Jonathan Brassow <jbrassow@xxxxxxxxxx>]

On Oct 8, 2010, at 12:53 PM, Peter Jones wrote:

This makes it possible to use DM_DEV_RENAME to add a uuid to a device so
long as one has not been previously set either with DM_DEV_CREATE or
with DM_DEV_RENAME. This is proposed as a fix to rhbz#584328 .

Also bump the minor number to 19.

Includes changes suggested by jbrassow.
---
drivers/md/dm-ioctl.c    |  112 ++++++++++++++++++++++++++++++++-------------
include/linux/dm-ioctl.h |    9 +++-
2 files changed, 86 insertions(+), 35 deletions(-)

diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c
index 3e39193..450dfe3 100644
--- a/drivers/md/dm-ioctl.c
+++ b/drivers/md/dm-ioctl.c
@@ -298,7 +298,7 @@ retry:
static struct mapped_device *dm_hash_rename(struct dm_ioctl *param,
   const char *new)
{
- char *new_name, *old_name;
+ char *new_data, *old_data;
struct hash_cell *hc;
struct dm_table *table;
struct mapped_device *md;
@@ -306,8 +306,8 @@ static struct mapped_device *dm_hash_rename(struct dm_ioctl *param,
/*
* duplicate new.
*/
- new_name = kstrdup(new, GFP_KERNEL);
- if (!new_name)
+ new_data = kstrdup(new, GFP_KERNEL);
+ if (!new_data)
return ERR_PTR(-ENOMEM);

down_write(&_hash_lock);
@@ -315,14 +315,28 @@ static struct mapped_device *dm_hash_rename(struct dm_ioctl *param,
/*
* Is new free ?
*/
- hc = __get_name_cell(new);
- if (hc) {
- DMWARN("asked to rename to an already-existing name %s -> %s",
-       param->name, new);
- dm_put(hc->md);
- up_write(&_hash_lock);
- kfree(new_name);
- return ERR_PTR(-EBUSY);
+ if (param->flags & DM_NEW_UUID_FLAG) {
+ hc = __get_uuid_cell(new);
+ if (hc) {
+ DMWARN("Unable to change uuid on device with an "
+       "already-existing uuid %s -> %s",
+       param->name, new);
+ dm_put(hc->md);
+ up_write(&_hash_lock);
+ kfree(new_data);
+ return ERR_PTR(-EBUSY);
+ }
+ } else {
+ hc = __get_name_cell(new);
+ if (hc) {
+ DMWARN("asked to rename to an already-existing name "
+       "%s -> %s",
+       param->name, new);
+ dm_put(hc->md);
+ up_write(&_hash_lock);
+ kfree(new_data);
+ return ERR_PTR(-EBUSY);
+ }
}

/*
@@ -333,19 +347,42 @@ static struct mapped_device *dm_hash_rename(struct dm_ioctl *param,
DMWARN("asked to rename a non-existent device %s -> %s",
      param->name, new);
up_write(&_hash_lock);
- kfree(new_name);
+ kfree(new_data);
return ERR_PTR(-ENXIO);
}

- /*
- * rename and move the name cell.
- */
- list_del(&hc->name_list);
- old_name = hc->name;
- mutex_lock(&dm_hash_cells_mutex);
- hc->name = new_name;
- mutex_unlock(&dm_hash_cells_mutex);
- list_add(&hc->name_list, _name_buckets + hash_str(new_name));
+ if (param->flags & DM_NEW_UUID_FLAG) {
+ /*
+ * Does this device already have a uuid?
+ */
+ if (hc->uuid) {
+ DMWARN("asked to change uuid of device with uuid "
+       "already set %s %s -> %s",
+       param->name, hc->uuid, param->uuid);
+ up_write(&_hash_lock);
+ kfree(new_data);
+ return ERR_PTR(-EINVAL);
+ }
+ /*
+ * reuuid and move the uuid cell.
+ */
+ list_del(&hc->uuid_list);
+ old_data = hc->uuid;
+ mutex_lock(&dm_hash_cells_mutex);
+ hc->uuid = new_data;
+ mutex_unlock(&dm_hash_cells_mutex);
+ list_add(&hc->uuid_list, _uuid_buckets + hash_str(new_data));
+ } else {
+ /*
+ * rename and move the name cell.
+ */
+ list_del(&hc->name_list);
+ old_data = hc->name;
+ mutex_lock(&dm_hash_cells_mutex);
+ hc->name = new_data;
+ mutex_unlock(&dm_hash_cells_mutex);
+ list_add(&hc->name_list, _name_buckets + hash_str(new_data));
+ }

/*
* Wake up any dm event waiters.
@@ -361,7 +398,7 @@ static struct mapped_device *dm_hash_rename(struct dm_ioctl *param,

md = hc->md;
up_write(&_hash_lock);
- kfree(old_name);
+ kfree(old_data);

return md;
}
@@ -774,21 +811,30 @@ static int invalid_str(char *str, void *end)
static int dev_rename(struct dm_ioctl *param, size_t param_size)
{
int r;
- char *new_name = (char *) param + param->data_start;
+ char *new_data = (char *) param + param->data_start;
struct mapped_device *md;

- if (new_name < param->data ||
-    invalid_str(new_name, (void *) param + param_size) ||
-    strlen(new_name) > DM_NAME_LEN - 1) {
- DMWARN("Invalid new logical volume name supplied.");
- return -EINVAL;
- }
+ if (param->flags & DM_NEW_UUID_FLAG) {
+ if (new_data < param->data ||
+    invalid_str(new_data, (void *) param + param_size) ||
+    strlen(new_data) > DM_UUID_LEN - 1) {
+ DMWARN("Invalid new device uuid supplied.");
+ return -EINVAL;
+ }
+ } else {
+ if (new_data < param->data ||
+    invalid_str(new_data, (void *) param + param_size) ||
+    strlen(new_data) > DM_NAME_LEN - 1) {
+ DMWARN("Invalid new device name supplied.");
+ return -EINVAL;
+ }

- r = check_name(new_name);
- if (r)
- return r;
+ r = check_name(new_data);
+ if (r)
+ return r;
+ }

- md = dm_hash_rename(param, new_name);
+ md = dm_hash_rename(param, new_data);
if (IS_ERR(md))
return PTR_ERR(md);

diff --git a/include/linux/dm-ioctl.h b/include/linux/dm-ioctl.h
index 49eab36..e369460 100644
--- a/include/linux/dm-ioctl.h
+++ b/include/linux/dm-ioctl.h
@@ -267,9 +267,9 @@ enum {
#define DM_DEV_SET_GEOMETRY _IOWR(DM_IOCTL, DM_DEV_SET_GEOMETRY_CMD, struct dm_ioctl)

#define DM_VERSION_MAJOR 4
-#define DM_VERSION_MINOR 18
+#define DM_VERSION_MINOR 19
#define DM_VERSION_PATCHLEVEL 0
-#define DM_VERSION_EXTRA "-ioctl (2010-06-29)"
+#define DM_VERSION_EXTRA "-ioctl (2010-10-07)"

/* Status bits */
#define DM_READONLY_FLAG (1 << 0) /* In/Out */
@@ -322,4 +322,9 @@ enum {
 */
#define DM_UEVENT_GENERATED_FLAG (1 << 13) /* Out */

+/*
+ * If set, rename operates on uuid, not name.
+ */
+#define DM_NEW_UUID_FLAG        (1 << 14) /* In */
+
#endif /* _LINUX_DM_IOCTL_H */
--
1.7.2.2

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