dm: allow targets to return output from messages they are sent

Could be useful for a target to return stats or other information.
If a target does DMEMIT() anything to @result from its .message method
then it must return 1 to the caller.

Signed-off-By: Mike Snitzer <snitzer@redhat.com>
This commit is contained in:
Mike Snitzer 2018-02-28 15:59:59 -05:00
parent da5dadb4f1
commit 1eb5fa849f
11 changed files with 21 additions and 12 deletions

View File

@ -3387,7 +3387,8 @@ static int process_invalidate_cblocks_message(struct cache *cache, unsigned coun
*
* The key migration_threshold is supported by the cache target core.
*/
static int cache_message(struct dm_target *ti, unsigned argc, char **argv)
static int cache_message(struct dm_target *ti, unsigned argc, char **argv,
char *result, unsigned maxlen)
{
struct cache *cache = ti->private;

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@ -2942,7 +2942,8 @@ static void crypt_resume(struct dm_target *ti)
* key set <key>
* key wipe
*/
static int crypt_message(struct dm_target *ti, unsigned argc, char **argv)
static int crypt_message(struct dm_target *ti, unsigned argc, char **argv,
char *result, unsigned maxlen)
{
struct crypt_config *cc = ti->private;
int key_size, ret = -EINVAL;

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@ -1635,7 +1635,8 @@ err:
DMEMIT("Error");
}
static int era_message(struct dm_target *ti, unsigned argc, char **argv)
static int era_message(struct dm_target *ti, unsigned argc, char **argv,
char *result, unsigned maxlen)
{
struct era *era = ti->private;

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@ -1595,7 +1595,7 @@ static int target_message(struct file *filp, struct dm_ioctl *param, size_t para
DMWARN("Target message sector outside device.");
r = -EINVAL;
} else if (ti->type->message)
r = ti->type->message(ti, argc, argv);
r = ti->type->message(ti, argc, argv, result, maxlen);
else {
DMWARN("Target type does not support messages");
r = -EINVAL;

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@ -887,7 +887,8 @@ static int log_writes_iterate_devices(struct dm_target *ti,
* Messages supported:
* mark <mark data> - specify the marked data.
*/
static int log_writes_message(struct dm_target *ti, unsigned argc, char **argv)
static int log_writes_message(struct dm_target *ti, unsigned argc, char **argv,
char *result, unsigned maxlen)
{
int r = -EINVAL;
struct log_writes_c *lc = ti->private;

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@ -1811,7 +1811,8 @@ static void multipath_status(struct dm_target *ti, status_type_t type,
spin_unlock_irqrestore(&m->lock, flags);
}
static int multipath_message(struct dm_target *ti, unsigned argc, char **argv)
static int multipath_message(struct dm_target *ti, unsigned argc, char **argv,
char *result, unsigned maxlen)
{
int r = -EINVAL;
struct dm_dev *dev;

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@ -3663,7 +3663,8 @@ static void raid_status(struct dm_target *ti, status_type_t type,
}
}
static int raid_message(struct dm_target *ti, unsigned int argc, char **argv)
static int raid_message(struct dm_target *ti, unsigned int argc, char **argv,
char *result, unsigned maxlen)
{
struct raid_set *rs = ti->private;
struct mddev *mddev = &rs->md;

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@ -466,7 +466,8 @@ static int process_set_region_mappings(struct switch_ctx *sctx,
*
* Only set_region_mappings is supported.
*/
static int switch_message(struct dm_target *ti, unsigned argc, char **argv)
static int switch_message(struct dm_target *ti, unsigned argc, char **argv,
char *result, unsigned maxlen)
{
static DEFINE_MUTEX(message_mutex);

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@ -3705,7 +3705,8 @@ static int process_release_metadata_snap_mesg(unsigned argc, char **argv, struct
* reserve_metadata_snap
* release_metadata_snap
*/
static int pool_message(struct dm_target *ti, unsigned argc, char **argv)
static int pool_message(struct dm_target *ti, unsigned argc, char **argv,
char *result, unsigned maxlen)
{
int r = -EINVAL;
struct pool_c *pt = ti->private;

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@ -87,7 +87,8 @@ typedef void (*dm_resume_fn) (struct dm_target *ti);
typedef void (*dm_status_fn) (struct dm_target *ti, status_type_t status_type,
unsigned status_flags, char *result, unsigned maxlen);
typedef int (*dm_message_fn) (struct dm_target *ti, unsigned argc, char **argv);
typedef int (*dm_message_fn) (struct dm_target *ti, unsigned argc, char **argv,
char *result, unsigned maxlen);
typedef int (*dm_prepare_ioctl_fn) (struct dm_target *ti,
struct block_device **bdev, fmode_t *mode);

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@ -270,9 +270,9 @@ 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 37
#define DM_VERSION_MINOR 38
#define DM_VERSION_PATCHLEVEL 0
#define DM_VERSION_EXTRA "-ioctl (2017-09-20)"
#define DM_VERSION_EXTRA "-ioctl (2018-02-28)"
/* Status bits */
#define DM_READONLY_FLAG (1 << 0) /* In/Out */