[PATCH 19/23] NFS: Split nfs_parse_mount_options() [ver #4]

From: David Howells
Date: Mon May 22 2017 - 11:56:14 EST

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Split nfs_parse_mount_options() to move the prologue, list-splitting and
epilogue into one function and the per-option processing into another.

Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
---

fs/nfs/internal.h | 3 +
fs/nfs/mount.c | 143 ++++++++++++++++++++++++++++++-----------------------
2 files changed, 83 insertions(+), 63 deletions(-)

diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
index af6ca28da48d..ed255241baa7 100644
--- a/fs/nfs/internal.h
+++ b/fs/nfs/internal.h
@@ -100,7 +100,10 @@ struct nfs_sb_config {
unsigned int version;
unsigned int minorversion;
char *fscache_uniq;
+ unsigned short protofamily;
+ unsigned short mountfamily;
bool need_mount;
+ bool sloppy;

struct {
struct sockaddr_storage address;
diff --git a/fs/nfs/mount.c b/fs/nfs/mount.c
index 8f22163a4cc7..99735a494d46 100644
--- a/fs/nfs/mount.c
+++ b/fs/nfs/mount.c
@@ -494,46 +494,18 @@ static int nfs_get_option_ul_bound(substring_t args[], unsigned long *option,
}

/*
- * Error-check and convert a string of mount options from user space into
- * a data structure. The whole mount string is processed; bad options are
- * skipped as they are encountered. If there were no errors, return 1;
- * otherwise return 0 (zero).
+ * Parse a single mount option in "key[=val]" form.
*/
-int nfs_parse_mount_options(char *raw, struct nfs_sb_config *cfg)
+static int nfs_sb_config_parse_option(struct nfs_sb_config *cfg, char *p)
{
- char *p, *string, *secdata;
- int rc, sloppy = 0, invalid_option = 0;
- unsigned short protofamily = AF_UNSPEC;
- unsigned short mountfamily = AF_UNSPEC;
-
- if (!raw) {
- dfprintk(MOUNT, "NFS: mount options string was NULL.\n");
- return 1;
- }
- dfprintk(MOUNT, "NFS: nfs mount opts='%s'\n", raw);
-
- secdata = alloc_secdata();
- if (!secdata)
- goto out_nomem;
-
- rc = security_sb_copy_data(raw, secdata);
- if (rc)
- goto out_security_failure;
-
- rc = security_sb_parse_opts_str(secdata, &cfg->lsm_opts);
- if (rc)
- goto out_security_failure;
-
- free_secdata(secdata);
+ char *string;
+ int rc;

- while ((p = strsep(&raw, ",")) != NULL) {
+ {
substring_t args[MAX_OPT_ARGS];
unsigned long option;
int token;

- if (!*p)
- continue;
-
dfprintk(MOUNT, "NFS: parsing nfs mount option '%s'\n", p);

token = match_token(p, nfs_mount_option_tokens, args);
@@ -737,7 +709,7 @@ int nfs_parse_mount_options(char *raw, struct nfs_sb_config *cfg)
if (!rc) {
dfprintk(MOUNT, "NFS: unrecognized "
"security flavor\n");
- return 0;
+ return -EINVAL;
}
break;
case Opt_proto:
@@ -747,22 +719,22 @@ int nfs_parse_mount_options(char *raw, struct nfs_sb_config *cfg)
token = match_token(string,
nfs_xprt_protocol_tokens, args);

- protofamily = AF_INET;
+ cfg->protofamily = AF_INET;
switch (token) {
case Opt_xprt_udp6:
- protofamily = AF_INET6;
+ cfg->protofamily = AF_INET6;
case Opt_xprt_udp:
cfg->flags &= ~NFS_MOUNT_TCP;
cfg->nfs_server.protocol = XPRT_TRANSPORT_UDP;
break;
case Opt_xprt_tcp6:
- protofamily = AF_INET6;
+ cfg->protofamily = AF_INET6;
case Opt_xprt_tcp:
cfg->flags |= NFS_MOUNT_TCP;
cfg->nfs_server.protocol = XPRT_TRANSPORT_TCP;
break;
case Opt_xprt_rdma6:
- protofamily = AF_INET6;
+ cfg->protofamily = AF_INET6;
case Opt_xprt_rdma:
/* vector side protocols to TCP */
cfg->flags |= NFS_MOUNT_TCP;
@@ -773,7 +745,7 @@ int nfs_parse_mount_options(char *raw, struct nfs_sb_config *cfg)
dfprintk(MOUNT, "NFS: unrecognized "
"transport protocol\n");
kfree(string);
- return 0;
+ return -EINVAL;
}
kfree(string);
break;
@@ -785,15 +757,15 @@ int nfs_parse_mount_options(char *raw, struct nfs_sb_config *cfg)
nfs_xprt_protocol_tokens, args);
kfree(string);

- mountfamily = AF_INET;
+ cfg->mountfamily = AF_INET;
switch (token) {
case Opt_xprt_udp6:
- mountfamily = AF_INET6;
+ cfg->mountfamily = AF_INET6;
case Opt_xprt_udp:
cfg->mount_server.protocol = XPRT_TRANSPORT_UDP;
break;
case Opt_xprt_tcp6:
- mountfamily = AF_INET6;
+ cfg->mountfamily = AF_INET6;
case Opt_xprt_tcp:
cfg->mount_server.protocol = XPRT_TRANSPORT_TCP;
break;
@@ -801,7 +773,7 @@ int nfs_parse_mount_options(char *raw, struct nfs_sb_config *cfg)
default:
dfprintk(MOUNT, "NFS: unrecognized "
"transport protocol\n");
- return 0;
+ return -EINVAL;
}
break;
case Opt_addr:
@@ -860,7 +832,7 @@ int nfs_parse_mount_options(char *raw, struct nfs_sb_config *cfg)
default:
dfprintk(MOUNT, "NFS: invalid "
"lookupcache argument\n");
- return 0;
+ return -EINVAL;
};
break;
case Opt_fscache_uniq:
@@ -893,7 +865,7 @@ int nfs_parse_mount_options(char *raw, struct nfs_sb_config *cfg)
default:
dfprintk(MOUNT, "NFS: invalid "
"local_lock argument\n");
- return 0;
+ return -EINVAL;
};
break;

@@ -901,7 +873,7 @@ int nfs_parse_mount_options(char *raw, struct nfs_sb_config *cfg)
* Special options
*/
case Opt_sloppy:
- sloppy = 1;
+ cfg->sloppy = 1;
dfprintk(MOUNT, "NFS: relaxing parsing rules\n");
break;
case Opt_userspace:
@@ -911,12 +883,63 @@ int nfs_parse_mount_options(char *raw, struct nfs_sb_config *cfg)
break;

default:
- invalid_option = 1;
dfprintk(MOUNT, "NFS: unrecognized mount option "
"'%s'\n", p);
+ return -EINVAL;
}
}

+ return 0;
+
+out_invalid_address:
+ printk(KERN_INFO "NFS: bad IP address specified: %s\n", p);
+ return -EINVAL;
+out_invalid_value:
+ printk(KERN_INFO "NFS: bad mount option value specified: %s\n", p);
+ return -EINVAL;
+out_nomem:
+ printk(KERN_INFO "NFS: not enough memory to parse option\n");
+ return -ENOMEM;
+}
+
+/*
+ * Error-check and convert a string of mount options from user space into
+ * a data structure. The whole mount string is processed; bad options are
+ * skipped as they are encountered. If there were no errors, return 1;
+ * otherwise return 0 (zero).
+ */
+int nfs_parse_mount_options(char *raw, struct nfs_sb_config *cfg)
+{
+ char *p, *secdata;
+ int rc, sloppy = 0, invalid_option = 0;
+
+ if (!raw) {
+ dfprintk(MOUNT, "NFS: mount options string was NULL.\n");
+ return 1;
+ }
+ dfprintk(MOUNT, "NFS: nfs mount opts='%s'\n", raw);
+
+ secdata = alloc_secdata();
+ if (!secdata)
+ goto out_nomem;
+
+ rc = security_sb_copy_data(raw, secdata);
+ if (rc)
+ goto out_security_failure;
+
+ rc = security_sb_parse_opts_str(secdata, &cfg->lsm_opts);
+ if (rc)
+ goto out_security_failure;
+
+ free_secdata(secdata);
+
+ while ((p = strsep(&raw, ",")) != NULL) {
+ if (!*p)
+ continue;
+ if (nfs_sb_config_parse_option(cfg, p) < 0)
+ invalid_option = true;
+ }
+
if (!sloppy && invalid_option)
return 0;

@@ -931,22 +954,26 @@ int nfs_parse_mount_options(char *raw, struct nfs_sb_config *cfg)
* verify that any proto=/mountproto= options match the address
* families in the addr=/mountaddr= options.
*/
- if (protofamily != AF_UNSPEC &&
- protofamily != cfg->nfs_server.address.ss_family)
+ if (cfg->protofamily != AF_UNSPEC &&
+ cfg->protofamily != cfg->nfs_server.address.ss_family)
goto out_proto_mismatch;

- if (mountfamily != AF_UNSPEC) {
+ if (cfg->mountfamily != AF_UNSPEC) {
if (cfg->mount_server.addrlen) {
- if (mountfamily != cfg->mount_server.address.ss_family)
+ if (cfg->mountfamily != cfg->mount_server.address.ss_family)
goto out_mountproto_mismatch;
} else {
- if (mountfamily != cfg->nfs_server.address.ss_family)
+ if (cfg->mountfamily != cfg->nfs_server.address.ss_family)
goto out_mountproto_mismatch;
}
}

return 1;

+out_minorversion_mismatch:
+ printk(KERN_INFO "NFS: mount option vers=%u does not support "
+ "minorversion=%u\n", cfg->version, cfg->minorversion);
+ return 0;
out_mountproto_mismatch:
printk(KERN_INFO "NFS: mount server address does not match mountproto= "
"option\n");
@@ -954,20 +981,10 @@ int nfs_parse_mount_options(char *raw, struct nfs_sb_config *cfg)
out_proto_mismatch:
printk(KERN_INFO "NFS: server address does not match proto= option\n");
return 0;
-out_invalid_address:
- printk(KERN_INFO "NFS: bad IP address specified: %s\n", p);
- return 0;
-out_invalid_value:
- printk(KERN_INFO "NFS: bad mount option value specified: %s\n", p);
- return 0;
-out_minorversion_mismatch:
- printk(KERN_INFO "NFS: mount option vers=%u does not support "
- "minorversion=%u\n", cfg->version, cfg->minorversion);
- return 0;
out_migration_misuse:
printk(KERN_INFO
"NFS: 'migration' not supported for this NFS version\n");
- return 0;
+ return -EINVAL;
out_nomem:
printk(KERN_INFO "NFS: not enough memory to parse option\n");
return 0;

Next message: David Miller: "Re: [RFC V1 1/1] net: cdc_ncm: Reduce memory use when kernel memory low"
Previous message: David Howells: "[PATCH 21/23] NFS: Add a small buffer in nfs_sb_config to avoid string dup [ver #4]"
In reply to: David Howells: "[PATCH 21/23] NFS: Add a small buffer in nfs_sb_config to avoid string dup [ver #4]"
Next in thread: David Howells: "[PATCH 14/23] procfs: Move proc_fill_super() to fs/proc/root.c [ver #4]"
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