[PATCHv3 0/2] target: make location of /var/targets configurable

[PATCHv3 0/2] target: make location of /var/targets configurable

[Lee Duncan]

These patches make the location of "/var/target" configurable,
though it still defauls to "/var/target".

This "target database directory" can only be changed
after the target_core_mod loads but before any
fabric drivers are loaded, and must be the pathname
of an existing directory.

This configuration is accomplished via the configfs
top-level target attribute "dbroot", i.e. dumping
out "/sys/kernel/config/target/dbroot" will normally
return "/var/target". Writing to this attribute
changes the loation where the kernel looks for the
target database.

The first patch creates this configurable value for
the "dbroot", and the second patch modifies users
of this directory to use this new attribute.

Changes from v2:
 * Add locking around access to target driver list

Changes from v1:
 * Only allow changing target DB root before it
   can be used by others
 * Validate that new DB root is a valid directory

Lee Duncan (2):
  target: make target db location configurable
  target: use new "dbroot" target attribute

 drivers/target/target_core_alua.c     |  6 ++--
 drivers/target/target_core_configfs.c | 62 +++++++++++++++++++++++++++++++++++
 drivers/target/target_core_internal.h |  6 ++++
 drivers/target/target_core_pr.c       |  2 +-
 4 files changed, 72 insertions(+), 4 deletions(-)

-- 
2.1.4

[PATCHv3 1/2] target: make target db location configurable

[Lee Duncan]

This commit adds the read-write attribute "dbroot",
in the top-level CONFIGFS (core) target directory,
normally /sys/kernel/config/target. This attribute
defaults to "/var/target" but can be changed by
writing a new pathname string to it. Changing this
attribute is only allowed when no fabric drivers
are loaded and the supplied value specifies an
existing directory.

Target modules that care about the target database
root directory will be modified to use this
attribute in a future commit.

Signed-off-by: Lee Duncan <lduncan@suse.com>
---
 drivers/target/target_core_configfs.c | 62 +++++++++++++++++++++++++++++++++++
 drivers/target/target_core_internal.h |  6 ++++
 2 files changed, 68 insertions(+)

diff --git a/drivers/target/target_core_configfs.c b/drivers/target/target_core_configfs.c
index 713c63d9681b..8cce79317971 100644
--- a/drivers/target/target_core_configfs.c
+++ b/drivers/target/target_core_configfs.c
@@ -99,6 +99,67 @@ static ssize_t target_core_item_version_show(struct config_item *item,
 
 CONFIGFS_ATTR_RO(target_core_item_, version);
 
+char db_root[DB_ROOT_LEN] = DB_ROOT_DEFAULT;
+static char db_root_stage[DB_ROOT_LEN];
+
+static ssize_t target_core_item_dbroot_show(struct config_item *item,
+					    char *page)
+{
+	return sprintf(page, "%s\n", db_root);
+}
+
+static ssize_t target_core_item_dbroot_store(struct config_item *item,
+					const char *page, size_t count)
+{
+	ssize_t read_bytes;
+	struct file *fp;
+
+	mutex_lock(&g_tf_lock);
+	if (!list_empty(&g_tf_list)) {
+		mutex_unlock(&g_tf_lock);
+		pr_err("db_root: cannot be changed: target drivers registered");
+		return -EINVAL;
+	}
+
+	if (count > (DB_ROOT_LEN - 1)) {
+		mutex_unlock(&g_tf_lock);
+		pr_err("db_root: count %d exceeds DB_ROOT_LEN-1: %u\n",
+		       (int)count, DB_ROOT_LEN - 1);
+		return -EINVAL;
+	}
+
+	read_bytes = snprintf(db_root_stage, DB_ROOT_LEN, "%s", page);
+	if (!read_bytes) {
+		mutex_unlock(&g_tf_lock);
+		return -EINVAL;
+	}
+	if (db_root_stage[read_bytes - 1] == '\n')
+		db_root_stage[read_bytes - 1] = '\0';
+
+	/* validate new db root before accepting it */
+	fp = filp_open(db_root_stage, O_RDONLY, 0);
+	if (IS_ERR(fp)) {
+		mutex_unlock(&g_tf_lock);
+		pr_err("db_root: cannot open: %s\n", db_root_stage);
+		return -EINVAL;
+	}
+	if (!S_ISDIR(fp->f_inode->i_mode)) {
+		filp_close(fp, 0);
+		mutex_unlock(&g_tf_lock);
+		pr_err("db_root: not a directory: %s\n", db_root_stage);
+		return -EINVAL;
+	}
+	filp_close(fp, 0);
+
+	strncpy(db_root, db_root_stage, read_bytes);
+
+	mutex_unlock(&g_tf_lock);
+
+	return read_bytes;
+}
+
+CONFIGFS_ATTR(target_core_item_, dbroot);
+
 static struct target_fabric_configfs *target_core_get_fabric(
 	const char *name)
 {
@@ -249,6 +310,7 @@ static struct configfs_group_operations target_core_fabric_group_ops = {
  */
 static struct configfs_attribute *target_core_fabric_item_attrs[] = {
 	&target_core_item_attr_version,
+	&target_core_item_attr_dbroot,
 	NULL,
 };
 
diff --git a/drivers/target/target_core_internal.h b/drivers/target/target_core_internal.h
index 040cf5202e54..c2a18b960c5d 100644
--- a/drivers/target/target_core_internal.h
+++ b/drivers/target/target_core_internal.h
@@ -156,4 +156,10 @@ void	target_stat_setup_mappedlun_default_groups(struct se_lun_acl *);
 /* target_core_xcopy.c */
 extern struct se_portal_group xcopy_pt_tpg;
 
+/* target_core_configfs.c */
+#define DB_ROOT_LEN		4096
+#define	DB_ROOT_DEFAULT		"/var/target"
+
+extern char db_root[];
+
 #endif /* TARGET_CORE_INTERNAL_H */
-- 
2.1.4

[PATCHv3 2/2] target: use new "dbroot" target attribute

[Lee Duncan]

This commit updates the target core ALUA and PR
modules to use the new "dbroot" attribute instead
of assuming the target database is in "/var/target".

Signed-off-by: Lee Duncan <lduncan@suse.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
---
 drivers/target/target_core_alua.c | 6 +++---
 drivers/target/target_core_pr.c   | 2 +-
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/target/target_core_alua.c b/drivers/target/target_core_alua.c
index 49aba4a31747..4c82bbe19003 100644
--- a/drivers/target/target_core_alua.c
+++ b/drivers/target/target_core_alua.c
@@ -932,7 +932,7 @@ static int core_alua_update_tpg_primary_metadata(
 			tg_pt_gp->tg_pt_gp_alua_access_status);
 
 	snprintf(path, ALUA_METADATA_PATH_LEN,
-		"/var/target/alua/tpgs_%s/%s", &wwn->unit_serial[0],
+		"%s/alua/tpgs_%s/%s", db_root, &wwn->unit_serial[0],
 		config_item_name(&tg_pt_gp->tg_pt_gp_group.cg_item));
 
 	rc = core_alua_write_tpg_metadata(path, md_buf, len);
@@ -1275,8 +1275,8 @@ static int core_alua_update_tpg_secondary_metadata(struct se_lun *lun)
 			atomic_read(&lun->lun_tg_pt_secondary_offline),
 			lun->lun_tg_pt_secondary_stat);
 
-	snprintf(path, ALUA_METADATA_PATH_LEN, "/var/target/alua/%s/%s/lun_%llu",
-			se_tpg->se_tpg_tfo->get_fabric_name(), wwn,
+	snprintf(path, ALUA_METADATA_PATH_LEN, "%s/alua/%s/%s/lun_%llu",
+			db_root, se_tpg->se_tpg_tfo->get_fabric_name(), wwn,
 			lun->unpacked_lun);
 
 	rc = core_alua_write_tpg_metadata(path, md_buf, len);
diff --git a/drivers/target/target_core_pr.c b/drivers/target/target_core_pr.c
index b1795735eafc..47463c99c318 100644
--- a/drivers/target/target_core_pr.c
+++ b/drivers/target/target_core_pr.c
@@ -1985,7 +1985,7 @@ static int __core_scsi3_write_aptpl_to_file(
 		return -EMSGSIZE;
 	}
 
-	snprintf(path, 512, "/var/target/pr/aptpl_%s", &wwn->unit_serial[0]);
+	snprintf(path, 512, "%s/pr/aptpl_%s", db_root, &wwn->unit_serial[0]);
 	file = filp_open(path, flags, 0600);
 	if (IS_ERR(file)) {
 		pr_err("filp_open(%s) for APTPL metadata"
-- 
2.1.4

Re: [PATCHv3 0/2] target: make location of /var/targets configurable

[Lee Duncan]

On 04/14/2016 06:18 PM, Lee Duncan wrote:
> These patches make the location of "/var/target" configurable,
> though it still defauls to "/var/target".
> 
> This "target database directory" can only be changed
> after the target_core_mod loads but before any
> fabric drivers are loaded, and must be the pathname
> of an existing directory.
> 
> This configuration is accomplished via the configfs
> top-level target attribute "dbroot", i.e. dumping
> out "/sys/kernel/config/target/dbroot" will normally
> return "/var/target". Writing to this attribute
> changes the loation where the kernel looks for the
> target database.
> 
> The first patch creates this configurable value for
> the "dbroot", and the second patch modifies users
> of this directory to use this new attribute.
> 
> Changes from v2:
>  * Add locking around access to target driver list
> 
> Changes from v1:
>  * Only allow changing target DB root before it
>    can be used by others
>  * Validate that new DB root is a valid directory
> 
> Lee Duncan (2):
>   target: make target db location configurable
>   target: use new "dbroot" target attribute
> 
>  drivers/target/target_core_alua.c     |  6 ++--
>  drivers/target/target_core_configfs.c | 62 +++++++++++++++++++++++++++++++++++
>  drivers/target/target_core_internal.h |  6 ++++
>  drivers/target/target_core_pr.c       |  2 +-
>  4 files changed, 72 insertions(+), 4 deletions(-)
> 

Ping?
-- 
Lee Duncan

Re: [PATCHv3 0/2] target: make location of /var/targets configurable

[Zhu Lingshan]

Hi experts,

I think these patches are great, and I am ready to help in user space.

Thanks,
BR
Zhu Lingshan

On 05/09/2016 09:17 AM, Lee Duncan wrote:
> On 04/14/2016 06:18 PM, Lee Duncan wrote:
>> These patches make the location of "/var/target" configurable,
>> though it still defauls to "/var/target".
>>
>> This "target database directory" can only be changed
>> after the target_core_mod loads but before any
>> fabric drivers are loaded, and must be the pathname
>> of an existing directory.
>>
>> This configuration is accomplished via the configfs
>> top-level target attribute "dbroot", i.e. dumping
>> out "/sys/kernel/config/target/dbroot" will normally
>> return "/var/target". Writing to this attribute
>> changes the loation where the kernel looks for the
>> target database.
>>
>> The first patch creates this configurable value for
>> the "dbroot", and the second patch modifies users
>> of this directory to use this new attribute.
>>
>> Changes from v2:
>>   * Add locking around access to target driver list
>>
>> Changes from v1:
>>   * Only allow changing target DB root before it
>>     can be used by others
>>   * Validate that new DB root is a valid directory
>>
>> Lee Duncan (2):
>>    target: make target db location configurable
>>    target: use new "dbroot" target attribute
>>
>>   drivers/target/target_core_alua.c     |  6 ++--
>>   drivers/target/target_core_configfs.c | 62 +++++++++++++++++++++++++++++++++++
>>   drivers/target/target_core_internal.h |  6 ++++
>>   drivers/target/target_core_pr.c       |  2 +-
>>   4 files changed, 72 insertions(+), 4 deletions(-)
>>
> Ping?

Re: [PATCHv3 0/2] target: make location of /var/targets configurable

[Lee Duncan]

Ping?

We really need to move the target database out of /var/target

On 04/14/2016 06:18 PM, Lee Duncan wrote:
> These patches make the location of "/var/target" configurable,
> though it still defauls to "/var/target".
> 
> This "target database directory" can only be changed
> after the target_core_mod loads but before any
> fabric drivers are loaded, and must be the pathname
> of an existing directory.
> 
> This configuration is accomplished via the configfs
> top-level target attribute "dbroot", i.e. dumping
> out "/sys/kernel/config/target/dbroot" will normally
> return "/var/target". Writing to this attribute
> changes the loation where the kernel looks for the
> target database.
> 
> The first patch creates this configurable value for
> the "dbroot", and the second patch modifies users
> of this directory to use this new attribute.
> 
> Changes from v2:
>  * Add locking around access to target driver list
> 
> Changes from v1:
>  * Only allow changing target DB root before it
>    can be used by others
>  * Validate that new DB root is a valid directory
> 
> Lee Duncan (2):
>   target: make target db location configurable
>   target: use new "dbroot" target attribute
> 
>  drivers/target/target_core_alua.c     |  6 ++--
>  drivers/target/target_core_configfs.c | 62 +++++++++++++++++++++++++++++++++++
>  drivers/target/target_core_internal.h |  6 ++++
>  drivers/target/target_core_pr.c       |  2 +-
>  4 files changed, 72 insertions(+), 4 deletions(-)
> 

-- 
Lee Duncan
SUSE Labs

Re: [PATCHv3 0/2] target: make location of /var/targets configurable

[Nicholas A. Bellinger]

On Thu, 2016-06-09 at 16:51 -0700, Lee Duncan wrote:
> Ping?
> 
> We really need to move the target database out of /var/target
> 

This series has already merged up for v4.7-rc1.