On Mon, Sep 11, 2023 at 06:38:13PM +0200, mwilck@xxxxxxxx wrote:
> From: Martin Wilck <mwilck@xxxxxxxx>
>
> If the bindings file is changed in a way that multipathd can't handle
> (e.g. by swapping the aliases of two maps), multipathd must not try
> to re-use an alias that is already used by another map. Creating
> or renaming a map with such an alias will fail. We already avoid
> this for some cases, but not for all. Fix it.
>
> Signed-off-by: Martin Wilck <mwilck@xxxxxxxx>
> Cc: David Bond <dbond@xxxxxxxx>
> ---
> libmultipath/alias.c | 33 ++++++++++++++++++++++++---------
> tests/alias.c | 2 +-
> 2 files changed, 25 insertions(+), 10 deletions(-)
>
> diff --git a/libmultipath/alias.c b/libmultipath/alias.c
> index 68f5d84..b5248f2 100644
> --- a/libmultipath/alias.c
> +++ b/libmultipath/alias.c
> @@ -120,7 +120,7 @@ static bool alias_already_taken(const char *alias, const char *map_wwid)
> if (dm_get_uuid(alias, wwid, sizeof(wwid)) == 0 &&
> strncmp(map_wwid, wwid, sizeof(wwid)) == 0)
> return false;
> - condlog(3, "%s: alias '%s' already taken, but not in bindings file. reselecting alias",
> + condlog(3, "%s: alias '%s' already taken, reselecting alias",
> map_wwid, alias);
> return true;
> }
> @@ -359,32 +359,47 @@ char *get_user_friendly_alias(const char *wwid, const char *file, const char *al
> rlookup_binding(f, buff, alias_old);
>
> if (strlen(buff) > 0) {
> - /* if buff is our wwid, it's already
> - * allocated correctly
> - */
> + /* If buff is our wwid, it's already allocated correctly. */
> if (strcmp(buff, wwid) == 0) {
> alias = strdup(alias_old);
> goto out;
> +
> } else {
> condlog(0, "alias %s already bound to wwid %s, cannot reuse",
> alias_old, buff);
> - goto new_alias;
Double semicolon. Doesn't really hurt anything, and it gets removed
later in the patchset, so:
Reviewed-by: Benjamin Marzinski <bmarzins@xxxxxxxxxx>
> + goto new_alias; ;
> }
> }
>
> - id = lookup_binding(f, wwid, &alias, NULL, 0);
> + /*
> + * Look for an existing alias in the bindings file.
> + * Pass prefix = NULL, so lookup_binding() won't try to allocate a new id.
> + */
> + lookup_binding(f, wwid, &alias, NULL, 0);
> if (alias) {
> - condlog(3, "Use existing binding [%s] for WWID [%s]",
> - alias, wwid);
> + if (alias_already_taken(alias, wwid)) {
> + free(alias);
> + alias = NULL;
> + } else
> + condlog(3, "Use existing binding [%s] for WWID [%s]",
> + alias, wwid);
> goto out;
> }
>
> - /* allocate the existing alias in the bindings file */
> + /* alias_old is already taken by our WWID, update bindings file. */
> id = scan_devname(alias_old, prefix);
>
> new_alias:
> if (id <= 0) {
> + /*
> + * no existing alias was provided, or allocating it
> + * failed. Try a new one.
> + */
> id = lookup_binding(f, wwid, &alias, prefix, 1);
> + if (id == 0 && alias_already_taken(alias, wwid)) {
> + free(alias);
> + alias = NULL;
> + }
> if (id <= 0)
> goto out;
> else
> diff --git a/tests/alias.c b/tests/alias.c
> index 3ca6c28..11f209e 100644
> --- a/tests/alias.c
> +++ b/tests/alias.c
> @@ -398,7 +398,7 @@ static void mock_self_alias(const char *alias, const char *wwid)
> will_return(__wrap_dm_get_uuid, wwid);
> }
>
> -#define USED_STR(alias_str, wwid_str) wwid_str ": alias '" alias_str "' already taken, but not in bindings file. reselecting alias\n"
> +#define USED_STR(alias_str, wwid_str) wwid_str ": alias '" alias_str "' already taken, reselecting alias\n"
>
> static void mock_failed_alias(const char *alias, char *msg)
> {
> --
> 2.42.0
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