From: Ian Kent <raven@themaw.net>
To: NeilBrown <neilb@suse.com>
Cc: autofs@vger.kernel.org
Subject: Re: [PATCH 1/3] use_hostname_for_mounts shouldn't prevent selection among replicas
Date: Mon, 29 Jan 2018 18:57:33 +0800 [thread overview]
Message-ID: <53698542-d9a9-49c6-9053-b5454364fd80@themaw.net> (raw)
In-Reply-To: <151721039458.27355.1715698671902330307.stgit@noble>
On 29/01/18 15:19, NeilBrown wrote:
> If several replicas have been specified for a mount point,
> and use_hostname_for_mount is set to "yes", the selection
> between these replicas is currently disabled and the last in
> the list is always chosen.
>
> There is little point selecting between different addresses
> for the one host in this case, but it is still worth
> selecting between different hosts, particularly if different
> weights have been specified.
>
> This patch restores the "prune_host_list()" functionality
> when use_hostname_for_mount is set, and modifies it slightly
> so that only on IP address for any host:/path entry in the
> config file is willl be successfully probed. After a
> success, further addresses from the same entry are skipped.
> This is achieved by tracking an entry number ("ent_num") for
> each 'struct host'.
Got it now.
Thanks Neil.
>
> Signed-off-by: NeilBrown <neilb@suse.com>
> ---
> include/replicated.h | 3 ++-
> modules/mount_nfs.c | 2 +-
> modules/replicated.c | 35 ++++++++++++++++++++---------------
> 3 files changed, 23 insertions(+), 17 deletions(-)
>
> diff --git a/include/replicated.h b/include/replicated.h
> index 69ab7800d96b..0f482d210066 100644
> --- a/include/replicated.h
> +++ b/include/replicated.h
> @@ -57,6 +57,7 @@
>
> struct host {
> char *name;
> + int ent_num;
> struct sockaddr *addr;
> size_t addr_len;
> unsigned int rr;
> @@ -70,7 +71,7 @@ struct host {
> };
>
> void seed_random(void);
> -struct host *new_host(const char *, struct sockaddr *, size_t,
> +struct host *new_host(const char *, int, struct sockaddr *, size_t,
> unsigned int, unsigned int, unsigned int);
> void free_host_list(struct host **);
> int parse_location(unsigned, struct host **, const char *, unsigned int);
> diff --git a/modules/mount_nfs.c b/modules/mount_nfs.c
> index bf712a9374ca..304bef29eec7 100644
> --- a/modules/mount_nfs.c
> +++ b/modules/mount_nfs.c
> @@ -236,7 +236,7 @@ int mount_mount(struct autofs_point *ap, const char *root, const char *name, int
> (vers & NFS4_VERS_MASK) != 0 &&
> !(vers & UDP6_REQUESTED)) {
> unsigned int v4_probe_ok = 0;
> - struct host *tmp = new_host(hosts->name,
> + struct host *tmp = new_host(hosts->name, 0,
> hosts->addr, hosts->addr_len,
> hosts->proximity,
> hosts->weight, hosts->options);
> diff --git a/modules/replicated.c b/modules/replicated.c
> index 3ac4c70f4062..c10efcd91deb 100644
> --- a/modules/replicated.c
> +++ b/modules/replicated.c
> @@ -83,7 +83,7 @@ void seed_random(void)
> return;
> }
>
> -struct host *new_host(const char *name,
> +struct host *new_host(const char *name, int ent_num,
> struct sockaddr *addr, size_t addr_len,
> unsigned int proximity, unsigned int weight,
> unsigned int options)
> @@ -116,6 +116,7 @@ struct host *new_host(const char *name,
> memset(new, 0, sizeof(struct host));
>
> new->name = tmp1;
> + new->ent_num = ent_num;
> new->addr_len = addr_len;
> new->addr = tmp2;
> new->proximity = proximity;
> @@ -714,7 +715,7 @@ done:
> int prune_host_list(unsigned logopt, struct host **list,
> unsigned int vers, int port)
> {
> - struct host *this, *last, *first;
> + struct host *this, *last, *first, *prev;
> struct host *new = NULL;
> unsigned int proximity, selected_version = 0;
> unsigned int v2_tcp_count, v3_tcp_count, v4_tcp_count;
> @@ -726,12 +727,6 @@ int prune_host_list(unsigned logopt, struct host **list,
> if (!*list)
> return 0;
>
> - /* If we're using the host name then there's no point probing
> - * avialability and respose time.
> - */
> - if (defaults_use_hostname_for_mounts())
> - return 1;
> -
> /* Use closest hosts to choose NFS version */
>
> first = *list;
> @@ -877,11 +872,18 @@ int prune_host_list(unsigned logopt, struct host **list,
>
> first = last;
> this = first;
> + prev = NULL;
> while (this) {
> struct host *next = this->next;
> if (!this->name) {
> remove_host(list, this);
> add_host(&new, this);
> + } else if (defaults_use_hostname_for_mounts() && prev &&
> + prev->ent_num == this->ent_num) {
> + /* When we use the hostname to mount, there is no
> + * point in probing every address it has, just one is
> + * enough. Skip the rest.
> + */
> } else {
> status = get_supported_ver_and_cost(logopt, this,
> selected_version, port);
> @@ -889,6 +891,7 @@ int prune_host_list(unsigned logopt, struct host **list,
> this->version = selected_version;
> remove_host(list, this);
> add_host(&new, this);
> + prev = this;
> }
> }
> this = next;
> @@ -901,7 +904,7 @@ int prune_host_list(unsigned logopt, struct host **list,
> }
>
> static int add_new_host(struct host **list,
> - const char *host, unsigned int weight,
> + const char *host, int ent_num, unsigned int weight,
> struct addrinfo *host_addr,
> unsigned int rr, unsigned int options)
> {
> @@ -940,7 +943,7 @@ static int add_new_host(struct host **list,
> else
> return 0;
>
> - new = new_host(host, host_addr->ai_addr, addr_len, prx, weight, options);
> + new = new_host(host, ent_num, host_addr->ai_addr, addr_len, prx, weight, options);
> if (!new)
> return 0;
>
> @@ -953,7 +956,7 @@ static int add_new_host(struct host **list,
> return 1;
> }
>
> -static int add_host_addrs(struct host **list, const char *host,
> +static int add_host_addrs(struct host **list, const char *host, int ent_num,
> unsigned int weight, unsigned int options)
> {
> struct addrinfo hints, *ni, *this;
> @@ -988,7 +991,7 @@ static int add_host_addrs(struct host **list, const char *host,
>
> this = ni;
> while (this) {
> - ret = add_new_host(list, host, weight, this, 0, options);
> + ret = add_new_host(list, host, ent_num, weight, this, 0, options);
> if (!ret)
> break;
> this = this->ai_next;
> @@ -1027,7 +1030,7 @@ try_name:
> rr++;
> this = ni;
> while (this) {
> - ret = add_new_host(list, host, weight, this, rr, options);
> + ret = add_new_host(list, host, ent_num, weight, this, rr, options);
> if (!ret)
> break;
> this = this->ai_next;
> @@ -1120,6 +1123,7 @@ int parse_location(unsigned logopt, struct host **hosts,
> {
> char *str, *p, *delim;
> unsigned int empty = 1;
> + int ent_num = 1;
>
> if (!list)
> return 0;
> @@ -1177,7 +1181,7 @@ int parse_location(unsigned logopt, struct host **hosts,
> }
>
> if (p != delim) {
> - if (!add_host_addrs(hosts, p, weight, options)) {
> + if (!add_host_addrs(hosts, p, ent_num, weight, options)) {
> if (empty) {
> p = next;
> continue;
> @@ -1199,7 +1203,7 @@ int parse_location(unsigned logopt, struct host **hosts,
> *delim = '\0';
> next = delim + 1;
>
> - if (!add_host_addrs(hosts, p, weight, options)) {
> + if (!add_host_addrs(hosts, p, ent_num, weight, options)) {
> p = next;
> continue;
> }
> @@ -1213,6 +1217,7 @@ int parse_location(unsigned logopt, struct host **hosts,
> return 0;
> }
>
> + ent_num ++;
> p = next;
> }
>
>
>
--
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next prev parent reply other threads:[~2018-01-29 10:57 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-29 7:19 [PATCH 0/3] Assorted autofs fixes NeilBrown
2018-01-29 7:19 ` [PATCH 1/3] use_hostname_for_mounts shouldn't prevent selection among replicas NeilBrown
2018-01-29 10:57 ` Ian Kent [this message]
2018-01-29 7:19 ` [PATCH 3/3] Makefiles.rules: remove 'samples' from SUBDIRS NeilBrown
2018-01-29 7:19 ` [PATCH 2/3] Fix monotonic_elapsed NeilBrown
2018-01-29 8:31 ` Ian Kent
2018-01-29 9:27 ` [PATCH 0/3] Assorted autofs fixes Ian Kent
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