On Tue, Jul 09, 2024 at 11:39:19PM +0200, Martin Wilck wrote:
> Signed-off-by: Martin Wilck <mwilck@xxxxxxxx>
> ---
> libmultipath/devmapper.c | 53 ++++++----------------------------------
> 1 file changed, 8 insertions(+), 45 deletions(-)
>
> diff --git a/libmultipath/devmapper.c b/libmultipath/devmapper.c
> index 859a861..6276041 100644
> --- a/libmultipath/devmapper.c
> +++ b/libmultipath/devmapper.c
> @@ -965,52 +965,15 @@ static int dm_type_match(const char *name, char *type)
>
> int dm_is_mpath(const char *name)
> {
> - int r = DM_IS_MPATH_ERR;
> - struct dm_task __attribute__((cleanup(cleanup_dm_task))) *dmt = NULL;
> - struct dm_info info;
> - uint64_t start, length;
> - char *target_type = NULL;
> - char *params;
> - const char *uuid;
> + char uuid[DM_UUID_LEN];
> + int rc = libmp_mapinfo(DM_MAP_BY_NAME,
> + (mapid_t) { .str = name },
> + (mapinfo_t) { .uuid = uuid, .tgt_type = TGT_MPATH });
>
> - if (!(dmt = libmp_dm_task_create(DM_DEVICE_TABLE)))
> - goto out;
> -
> - if (!dm_task_set_name(dmt, name))
> - goto out;
> -
> - if (!libmp_dm_task_run(dmt)) {
> - dm_log_error(3, DM_DEVICE_TABLE, dmt);
> - goto out;
> - }
> -
> - if (!dm_task_get_info(dmt, &info))
> - goto out;
> -
> - r = DM_IS_MPATH_NO;
> -
> - if (!info.exists)
> - goto out;
> -
> - uuid = dm_task_get_uuid(dmt);
> -
> - if (!uuid || strncmp(uuid, UUID_PREFIX, UUID_PREFIX_LEN) != 0)
> - goto out;
> -
> - /* Fetch 1st target */
> - if (dm_get_next_target(dmt, NULL, &start, &length, &target_type,
> - ¶ms) != NULL)
> - /* multiple targets */
> - goto out;
> -
> - if (!target_type || strcmp(target_type, TGT_MPATH) != 0)
> - goto out;
> -
> - r = DM_IS_MPATH_YES;
> -out:
> - if (r < 0)
> - condlog(3, "%s: dm command failed in %s: %s", name, __func__, strerror(errno));
> - return r;
Since dm_get_events() and watch_dmevents() need to differentiate between
DM_IS_MPATH_NO and DM_IS_MPATH_ERR, this function needs to return
DM_IS_MPATH_ERR if libmp_mapinfo() returns DM_ERR.
Looking over this function, I did notice one thing. It returns
DM_IS_MPATH_ERR if dm_task_get_info() fails, while libmp_mapinfo__()
returns DMP_NOT_FOUND if dm_task_get_info() fails. Looking at the
current lvm code, I can't see a way for dm_task_get_info() to fail
if we just called libmp_dm_task_run() and it succeeded. On the other
hand dm_task_get_info() failing does seem to be an error, not a
a sign that the device doesn't exist, so perhaps ibmp_mapinfo__()
should treat it like one. Although most of our code doesn't, and like I
said, I don't see how it could fail unless dm_task_run() already failed
(or wasn't called).
Any thoughts?
-Ben
> + if (rc != DMP_OK || strncmp(uuid, UUID_PREFIX, UUID_PREFIX_LEN))
> + return DM_IS_MPATH_NO;
> + else
> + return DM_IS_MPATH_YES;
> }
>
> int dm_map_present_by_wwid(const char *wwid)
> --
> 2.45.2
