On Wed, May 04, 2016 at 07:57:25AM +0200, Hannes Reinecke wrote:
> Instead of generating the cookie internally we should be passing
> it in as an argument; that will allow for cookie reuse.
While this one doesn't break anything, it seems unhelpful. We are always
dealing with the cookies inside dm_simplecmd and dm_addmap. Once you
wait on a cookie (after more research, calling dm_udev_complete() looks
like it's always the wrong thing to do, but I'll get to that later). You
can't reuse it. You must have device-mapper give you an new
autogenerated cookie. Because of this, there is no reason why anything
outside of dm_simplecmd or dm_addmap ever needs to know about cookies.
We are adding an extra parameter that needs to always be set to 0 (I
know that a later patch uses the cookie value to remove need_sync, and
I'll get to that later as well).
-Ben
>
> Signed-off-by: Hannes Reinecke <hare@xxxxxxx>
> ---
> libmultipath/devmapper.c | 25 ++++++++++++++++---------
> 1 file changed, 16 insertions(+), 9 deletions(-)
>
> diff --git a/libmultipath/devmapper.c b/libmultipath/devmapper.c
> index fb202e8..48e7d50 100644
> --- a/libmultipath/devmapper.c
> +++ b/libmultipath/devmapper.c
> @@ -207,11 +207,12 @@ dm_prereq (void)
> #define do_deferred(x) ((x) == DEFERRED_REMOVE_ON || (x) == DEFERRED_REMOVE_IN_PROGRESS)
>
> static int
> -dm_simplecmd (int task, const char *name, int no_flush, int need_sync, uint16_t udev_flags, int deferred_remove) {
> +dm_simplecmd (int task, const char *name, int no_flush, int need_sync,
> + uint16_t udev_flags, int deferred_remove, uint32_t *cookie)
> +{
> int r = 0;
> int udev_wait_flag = (need_sync && (task == DM_DEVICE_RESUME ||
> task == DM_DEVICE_REMOVE));
> - uint32_t cookie = 0;
> struct dm_task *dmt;
>
> if (!(dmt = dm_task_create (task)))
> @@ -231,18 +232,18 @@ dm_simplecmd (int task, const char *name, int no_flush, int need_sync, uint16_t
> dm_task_deferred_remove(dmt);
> #endif
> if (udev_wait_flag &&
> - !dm_task_set_cookie(dmt, &cookie,
> + !dm_task_set_cookie(dmt, cookie,
> DM_UDEV_DISABLE_LIBRARY_FALLBACK | udev_flags)) {
> - dm_udev_complete(cookie);
> + dm_udev_complete(*cookie);
> goto out;
> }
> r = dm_task_run (dmt);
>
> if (udev_wait_flag) {
> if (!r)
> - dm_udev_complete(cookie);
> + dm_udev_complete(*cookie);
> else
> - dm_udev_wait(cookie);
> + dm_udev_wait(*cookie);
> }
> out:
> dm_task_destroy (dmt);
> @@ -251,18 +252,24 @@ dm_simplecmd (int task, const char *name, int no_flush, int need_sync, uint16_t
>
> extern int
> dm_simplecmd_flush (int task, const char *name, uint16_t udev_flags) {
> - return dm_simplecmd(task, name, 0, 1, udev_flags, 0);
> + uint32_t cookie = 0;
> +
> + return dm_simplecmd(task, name, 0, 1, udev_flags, 0, &cookie);
> }
>
> extern int
> dm_simplecmd_noflush (int task, const char *name, int needsync, uint16_t udev_flags) {
> - return dm_simplecmd(task, name, 1, needsync, udev_flags, 0);
> + uint32_t cookie = 0;
> +
> + return dm_simplecmd(task, name, 1, needsync, udev_flags, 0, &cookie);
> }
>
> static int
> dm_device_remove (const char *name, int needsync, int deferred_remove) {
> + uint32_t cookie = 0;
> +
> return dm_simplecmd(DM_DEVICE_REMOVE, name, 0, needsync, 0,
> - deferred_remove);
> + deferred_remove, &cookie);
> }
>
> static int
> --
> 2.6.6
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