If a multipath device's registered key is changed, mpathpersist needs to update the key in multipathd before it registers the new key on the paths. This means that there is a time when multipathd thinks the paths should be using the new key, but none of them are. If a path is restored after mpathpersist checks which paths are usable to set the key on, but before it sets the key on any path, multipathd will see that the new key is not registered on any paths, and think that the key has been preempted or cleared. This will leave the path without a key, and possibly make multipathd think the device does not hold the reservation, even if it does.
To avoid this, multipathd will now remember the old key when registering a new one. Once the registration is finished, and (un)setprstatus is called, multipathd will forget the old key. Until then, multipathd will check for either key when it looks to see if there is an existing key. If the registration fails and the key get reverted, multipathd will also forget the old key. Signed-off-by: Benjamin Marzinski <[email protected]> --- libmultipath/prkey.c | 16 ++++++++++++++-- libmultipath/structs.h | 1 + multipathd/main.c | 12 +++++++++++- 3 files changed, 26 insertions(+), 3 deletions(-) diff --git a/libmultipath/prkey.c b/libmultipath/prkey.c index c66d293b..4fbde5ad 100644 --- a/libmultipath/prkey.c +++ b/libmultipath/prkey.c @@ -222,10 +222,22 @@ int set_prkey(struct config *conf, struct multipath *mpp, uint64_t prkey, } else ret = do_prkey(fd, mpp->wwid, NULL, PRKEY_WRITE); - if (ret == 0) + if (ret == 0) { + /* + * If you are reverting back to the old key, because you + * did not successfully set a new key, don't remember the + * key you never successfully set. + */ + if (get_be64(mpp->old_pr_key) == prkey) + memset(&mpp->old_pr_key, 0, 8); + else + memcpy(&mpp->old_pr_key, &mpp->reservation_key, 8); select_reservation_key(conf, mpp); - if (get_be64(mpp->reservation_key) != prkey) + } + if (get_be64(mpp->reservation_key) != prkey) { + memset(&mpp->old_pr_key, 0, 8); ret = 1; + } out_file: close(fd); out: diff --git a/libmultipath/structs.h b/libmultipath/structs.h index a206a7d1..9247e74f 100644 --- a/libmultipath/structs.h +++ b/libmultipath/structs.h @@ -520,6 +520,7 @@ struct multipath { /* persistent management data*/ int prkey_source; struct be64 reservation_key; + struct be64 old_pr_key; uint8_t sa_flags; int prflag; int prhold; diff --git a/multipathd/main.c b/multipathd/main.c index 86d9a098..39d4f8cd 100644 --- a/multipathd/main.c +++ b/multipathd/main.c @@ -4249,6 +4249,7 @@ void set_pr(struct multipath *mpp) { mpp->ever_registered_pr = true; mpp->prflag = PR_SET; + memset(&mpp->old_pr_key, 0, 8); } void unset_pr(struct multipath *mpp) @@ -4256,6 +4257,7 @@ void unset_pr(struct multipath *mpp) mpp->prflag = PR_UNSET; mpp->prhold = PR_UNSET; mpp->sa_flags = 0; + memset(&mpp->old_pr_key, 0, 8); } /* @@ -4308,7 +4310,15 @@ static int update_map_pr(struct multipath *mpp, struct path *pp) dumpHex((char *)keyp, 8, 1); } - if (!memcmp(&mpp->reservation_key, keyp, 8)) + /* + * If you are in the middle of updating a key (old_pr_key + * is set) check for either the new key or the old key, + * since you might be checking before any paths have + * updated their keys. + */ + if (!memcmp(&mpp->reservation_key, keyp, 8) || + (get_be64(mpp->old_pr_key) && + !memcmp(&mpp->old_pr_key, keyp, 8))) isFound = 1; } -- 2.50.1
