scoutfs: add server_addr mount option

Add a server_addr mount option that takes an ipv4 address.  This will be
used by the upcoming changes to quorum voting to indicate that a mount
should participate in voting and to specify the address that its server
should listen on.

Signed-off-by: Zach Brown <zab@versity.com>

kmod/src/options.c

@@ -27,6 +27,7 @@
 #include "super.h"
 
 static const match_table_t tokens = {
+	{Opt_server_addr, "server_addr=%s"},
 	{Opt_uniq_name, "uniq_name=%s"},
 	{Opt_err, NULL}
 };
@@ -50,12 +51,54 @@ u32 scoutfs_option_u32(struct super_block *sb, int token)
 	return 0;
 }
 
+/* The caller's string is null terminted and can be clobbered */
+static int parse_ipv4(struct super_block *sb, char *str,
+		      struct sockaddr_in *sin)
+{
+	unsigned long port = 0;
+	__be32 addr;
+	char *c;
+	int ret;
+
+	/* null term port, if specified */
+	c = strchr(str, ':');
+	if (c)
+		*c = '\0';
+
+	/* parse addr */
+	addr = in_aton(str);
+	if (ipv4_is_multicast(addr) || ipv4_is_lbcast(addr) ||
+	    ipv4_is_zeronet(addr) ||
+	    ipv4_is_local_multicast(addr)) {
+		scoutfs_err(sb, "invalid unicast ipv4 address: %s", str);
+		return -EINVAL;
+	}
+
+	/* parse port, if specified */
+	if (c) {
+		c++;
+		ret = kstrtoul(c, 0, &port);
+		if (ret != 0 || port == 0 || port >= U16_MAX) {
+			scoutfs_err(sb, "invalid port in ipv4 address: %s", c);
+			return -EINVAL;
+		}
+	}
+
+	sin->sin_family = AF_INET;
+	sin->sin_addr.s_addr = addr;
+	sin->sin_port = cpu_to_be16(port);
+
+	return 0;
+}
+
 int scoutfs_parse_options(struct super_block *sb, char *options,
 			  struct mount_options *parsed)
 {
+	char ipstr[INET_ADDRSTRLEN + 1];
 	substring_t args[MAX_OPT_ARGS];
 	int token, len;
 	char *p;
+	int ret;
 
 	/* Set defaults */
 	memset(parsed, 0, sizeof(*parsed));
@@ -66,6 +109,13 @@ int scoutfs_parse_options(struct super_block *sb, char *options,
 
 		token = match_token(p, tokens, args);
 		switch (token) {
+		case Opt_server_addr:
+
+			match_strlcpy(ipstr, args, ARRAY_SIZE(ipstr));
+			ret = parse_ipv4(sb, ipstr, &parsed->server_addr);
+			if (ret < 0)
+				return ret;
+			break;
 		case Opt_uniq_name:
 			len = match_strlcpy(parsed->uniq_name, args,
 					    SCOUTFS_UNIQUE_NAME_MAX_BYTES);

kmod/src/options.h

@@ -2,6 +2,7 @@
 #define	_SCOUTFS_OPTIONS_H_
 
 #include <linux/fs.h>
+#include <linux/in.h>
 #include "format.h"
 
 enum {
@@ -10,11 +11,13 @@ enum {
 	 * the number of items in each block as though the blocks were tiny.
 	 */
 	Opt_btree_force_tiny_blocks,
+	Opt_server_addr,
 	Opt_uniq_name,
 	Opt_err,
 };
 
 struct mount_options {
+	struct sockaddr_in server_addr;
 	char uniq_name[SCOUTFS_UNIQUE_NAME_MAX_BYTES];
 };
 

kmod/src/super.c

@@ -138,11 +138,23 @@ static int scoutfs_show_options(struct seq_file *seq, struct dentry *root)
 	struct super_block *sb = root->d_sb;
 	struct mount_options *opts = &SCOUTFS_SB(sb)->opts;
 
+	seq_printf(seq, ",server_addr="SIN_FMT, SIN_ARG(&opts->server_addr));
 	seq_printf(seq, ",uniq_name=%s", opts->uniq_name);
 
 	return 0;
 }
 
+static ssize_t server_addr_show(struct kobject *kobj,
+			      struct kobj_attribute *attr, char *buf)
+{
+	struct super_block *sb = SCOUTFS_SYSFS_ATTRS_SB(kobj);
+	struct mount_options *opts = &SCOUTFS_SB(sb)->opts;
+
+	return snprintf(buf, PAGE_SIZE, SIN_FMT"\n",
+			SIN_ARG(&opts->server_addr));
+}
+SCOUTFS_ATTR_RO(server_addr);
+
 static ssize_t uniq_name_show(struct kobject *kobj,
 			      struct kobj_attribute *attr, char *buf)
 {
@@ -154,6 +166,7 @@ static ssize_t uniq_name_show(struct kobject *kobj,
 SCOUTFS_ATTR_RO(uniq_name);
 
 static struct attribute *mount_options_attrs[] = {
+	SCOUTFS_ATTR_PTR(server_addr),
 	SCOUTFS_ATTR_PTR(uniq_name),
 	NULL,
 };