NFS: Use super.c for NFSROOT mount option parsing

Replace duplicate code in NFSROOT for mounting an NFS server on '/' with logic that uses the existing mainline text-based logic in the NFS client. Add documenting comments where appropriate. Note that this means NFSROOT mounts now use the same default settings as v2/v3 mounts done via mount(2) from user space. vers=3,tcp,rsize=<negotiated default>,wsize=<negotiated default> As before, however, no version/protocol negotiation with the server is done. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

NFS: Use super.c for NFSROOT mount option parsing
Replace duplicate code in NFSROOT for mounting an NFS server on '/' with logic that uses the existing mainline text-based logic in the NFS client. Add documenting comments where appropriate. Note that this means NFSROOT mounts now use the same default settings as v2/v3 mounts done via mount(2) from user space. vers=3,tcp,rsize=<negotiated default>,wsize=<negotiated default> As before, however, no version/protocol negotiation with the server is done. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Chuck Lever · Trond Myklebust
1 parent 60ac03685b
Showing 3 changed files with 187 additions and 17 deletions Side-by-side Diff
fs/nfs/nfsroot.c
include/linux/nfs_fs.h
init/do_mounts.c
@@ -3,9 +3,10 @@
  *
  *  Allow an NFS filesystem to be mounted as root. The way this works is:
  *     (1) Use the IP autoconfig mechanism to set local IP addresses and routes.
- *     (2) Handle RPC negotiation with the system which replied to RARP or
- *         was reported as a boot server by BOOTP or manually.
- *     (3) The actual mounting is done later, when init() is running.
+ *     (2) Construct the device string and the options string using DHCP
+ *         option 17 and/or kernel command line options.
+ *     (3) When mount_root() sets up the root file system, pass these strings
+ *         to the NFS client's regular mount interface via sys_mount().
  *
  *
  *	Changes:
@@ -65,7 +66,8 @@
  *	Hua Qin		:	Support for mounting root file system via
  *				NFS over TCP.
  *	Fabian Frederick:	Option parser rebuilt (using parser lib)
-*/
+ *	Chuck Lever	:	Use super.c's text-based mount option parsing
+ */
  
 #include <linux/types.h>
 #include <linux/string.h>
  
  
@@ -101,12 +103,18 @@
 /* Parameters passed from the kernel command line */
 static char nfs_root_parms[256] __initdata = "";
  
+/* Text-based mount options passed to super.c */
+static char nfs_root_options[256] __initdata = "";
+
 /* Address of NFS server */
 static __be32 servaddr __initdata = 0;
  
 /* Name of directory to mount */
-static char nfs_export_path[NFS_MAXPATHLEN + 1] __initdata = { 0, };
+static char nfs_export_path[NFS_MAXPATHLEN + 1] __initdata = "";
  
+/* server:export path string passed to super.c */
+static char nfs_root_device[NFS_MAXPATHLEN + 1] __initdata = "";
+
 /* NFS-related data */
 static struct nfs_mount_data nfs_data __initdata = { 0, };/* NFS mount info */
 static int nfs_port __initdata = 0;		/* Port to connect to for NFS */
@@ -537,7 +545,7 @@
  *  Get the NFS port numbers and file handle, and return the prepared 'data'
  *  argument for mount() if everything went OK. Return NULL otherwise.
  */
-void * __init nfs_root_data(void)
+void * __init old_nfs_root_data(void)
 {
 	if (root_nfs_init() < 0
 	 || root_nfs_ports() < 0
@@ -545,5 +553,167 @@
 		return NULL;
 	set_sockaddr((struct sockaddr_in *) &nfs_data.addr, servaddr, htons(nfs_port));
 	return (void*)&nfs_data;
+}
+
+static int __init root_nfs_copy(char *dest, const char *src,
+				     const size_t destlen)
+{
+	if (strlcpy(dest, src, destlen) > destlen)
+		return -1;
+	return 0;
+}
+
+static int __init root_nfs_cat(char *dest, const char *src,
+				  const size_t destlen)
+{
+	if (strlcat(dest, src, destlen) > destlen)
+		return -1;
+	return 0;
+}
+
+/*
+ * Parse out root export path and mount options from
+ * passed-in string @incoming.
+ *
+ * Copy the export path into @exppath.
+ */
+static int __init root_nfs_parse_options(char *incoming, char *exppath,
+					 const size_t exppathlen)
+{
+	char *p;
+
+	/*
+	 * Set the NFS remote path
+	 */
+	p = strsep(&incoming, ",");
+	if (*p != '\0' && strcmp(p, "default") != 0)
+		if (root_nfs_copy(exppath, p, exppathlen))
+			return -1;
+
+	/*
+	 * @incoming now points to the rest of the string; if it
+	 * contains something, append it to our root options buffer
+	 */
+	if (incoming != NULL && *incoming != '\0')
+		if (root_nfs_cat(nfs_root_options, incoming,
+						sizeof(nfs_root_options)))
+			return -1;
+
+	/*
+	 * Possibly prepare for more options to be appended
+	 */
+	if (nfs_root_options[0] != '\0' &&
+	    nfs_root_options[strlen(nfs_root_options)] != ',')
+		if (root_nfs_cat(nfs_root_options, ",",
+						sizeof(nfs_root_options)))
+			return -1;
+
+	return 0;
+}
+
+/*
+ *  Decode the export directory path name and NFS options from
+ *  the kernel command line.  This has to be done late in order to
+ *  use a dynamically acquired client IP address for the remote
+ *  root directory path.
+ *
+ *  Returns zero if successful; otherwise -1 is returned.
+ */
+static int __init root_nfs_data(char *cmdline)
+{
+	char addr_option[sizeof("nolock,addr=") + INET_ADDRSTRLEN + 1];
+	int len, retval = -1;
+	char *tmp = NULL;
+	const size_t tmplen = sizeof(nfs_export_path);
+
+	tmp = kzalloc(tmplen, GFP_KERNEL);
+	if (tmp == NULL)
+		goto out_nomem;
+	strcpy(tmp, NFS_ROOT);
+
+	if (root_server_path[0] != '\0') {
+		dprintk("Root-NFS: DHCPv4 option 17: %s\n",
+			root_server_path);
+		if (root_nfs_parse_options(root_server_path, tmp, tmplen))
+			goto out_optionstoolong;
+	}
+
+	if (cmdline[0] != '\0') {
+		dprintk("Root-NFS: nfsroot=%s\n", cmdline);
+		if (root_nfs_parse_options(cmdline, tmp, tmplen))
+			goto out_optionstoolong;
+	}
+
+	/*
+	 * Append mandatory options for nfsroot so they override
+	 * what has come before
+	 */
+	snprintf(addr_option, sizeof(addr_option), "nolock,addr=%pI4",
+			&servaddr);
+	if (root_nfs_cat(nfs_root_options, addr_option,
+						sizeof(nfs_root_options)))
+		goto out_optionstoolong;
+
+	/*
+	 * Set up nfs_root_device.  For NFS mounts, this looks like
+	 *
+	 *	server:/path
+	 *
+	 * At this point, utsname()->nodename contains our local
+	 * IP address or hostname, set by ipconfig.  If "%s" exists
+	 * in tmp, substitute the nodename, then shovel the whole
+	 * mess into nfs_root_device.
+	 */
+	len = snprintf(nfs_export_path, sizeof(nfs_export_path),
+				tmp, utsname()->nodename);
+	if (len > (int)sizeof(nfs_export_path))
+		goto out_devnametoolong;
+	len = snprintf(nfs_root_device, sizeof(nfs_root_device),
+				"%pI4:%s", &servaddr, nfs_export_path);
+	if (len > (int)sizeof(nfs_root_device))
+		goto out_devnametoolong;
+
+	retval = 0;
+
+out:
+	kfree(tmp);
+	return retval;
+out_nomem:
+	printk(KERN_ERR "Root-NFS: could not allocate memory\n");
+	goto out;
+out_optionstoolong:
+	printk(KERN_ERR "Root-NFS: mount options string too long\n");
+	goto out;
+out_devnametoolong:
+	printk(KERN_ERR "Root-NFS: root device name too long.\n");
+	goto out;
+}
+
+/**
+ * nfs_root_data - Return prepared 'data' for NFSROOT mount
+ * @root_device: OUT: address of string containing NFSROOT device
+ * @root_data: OUT: address of string containing NFSROOT mount options
+ *
+ * Returns zero and sets @root_device and @root_data if successful,
+ * otherwise -1 is returned.
+ */
+int __init nfs_root_data(char **root_device, char **root_data)
+{
+#ifdef NFSROOT_DEBUG
+	nfs_debug |= NFSDBG_ROOT | NFSDBG_MOUNT;
+#endif	/* NFSROOT_DEBUG */
+
+	servaddr = root_server_addr;
+	if (servaddr == htonl(INADDR_NONE)) {
+		printk(KERN_ERR "Root-NFS: no NFS server address\n");
+		return -1;
+	}
+
+	if (root_nfs_data(nfs_root_parms) < 0)
+		return -1;
+
+	*root_device = nfs_root_device;
+	*root_data = nfs_root_options;
+	return 0;
 }
@@ -364,6 +364,7 @@
 extern void nfs_put_lock_context(struct nfs_lock_context *l_ctx);
 extern u64 nfs_compat_user_ino64(u64 fileid);
 extern void nfs_fattr_init(struct nfs_fattr *fattr);
+extern unsigned long nfs_inc_attr_generation_counter(void);
  
 extern struct nfs_fattr *nfs_alloc_fattr(void);
  
  
@@ -379,9 +380,12 @@
 	kfree(fh);
 }
  
+/*
+ * linux/fs/nfs/nfsroot.c
+ */
+extern int  nfs_root_data(char **root_device, char **root_data); /*__init*/
 /* linux/net/ipv4/ipconfig.c: trims ip addr off front of name, too. */
 extern __be32 root_nfs_parse_addr(char *name); /*__init*/
-extern unsigned long nfs_inc_attr_generation_counter(void);
  
 /*
  * linux/fs/nfs/file.c
@@ -583,10 +587,6 @@
 		ino ^= fileid >> (sizeof(u64)-sizeof(ino_t)) * 8;
 	return ino;
 }
-
-/* NFS root */
-
-extern void * nfs_root_data(void);
  
 #define nfs_wait_event(clnt, wq, condition)				\
 ({									\
@@ -291,13 +291,13 @@
 #ifdef CONFIG_ROOT_NFS
 static int __init mount_nfs_root(void)
 {
-	void *data = nfs_root_data();
+	char *root_dev, *root_data;
  
-	create_dev("/dev/root", ROOT_DEV);
-	if (data &&
-	    do_mount_root("/dev/root", "nfs", root_mountflags, data) == 0)
-		return 1;
-	return 0;
+	if (nfs_root_data(&root_dev, &root_data) != 0)
+		return 0;
+	if (do_mount_root(root_dev, "nfs", root_mountflags, root_data) != 0)
+		return 0;
+	return 1;
 }
 #endif
...	...	@@ -3,9 +3,10 @@
3	3	*
4	4	* Allow an NFS filesystem to be mounted as root. The way this works is:
5	5	* (1) Use the IP autoconfig mechanism to set local IP addresses and routes.
6		- * (2) Handle RPC negotiation with the system which replied to RARP or
7		- * was reported as a boot server by BOOTP or manually.
8		- * (3) The actual mounting is done later, when init() is running.
	6	+ * (2) Construct the device string and the options string using DHCP
	7	+ * option 17 and/or kernel command line options.
	8	+ * (3) When mount_root() sets up the root file system, pass these strings
	9	+ * to the NFS client's regular mount interface via sys_mount().
9	10	*
10	11	*
11	12	* Changes:
...	...	@@ -65,7 +66,8 @@
65	66	* Hua Qin : Support for mounting root file system via
66	67	* NFS over TCP.
67	68	* Fabian Frederick: Option parser rebuilt (using parser lib)
68		-*/
	69	+ * Chuck Lever : Use super.c's text-based mount option parsing
	70	+ */
69	71
70	72	#include <linux/types.h>
71	73	#include <linux/string.h>
72	74
73	75
...	...	@@ -101,12 +103,18 @@
101	103	/* Parameters passed from the kernel command line */
102	104	static char nfs_root_parms[256] __initdata = "";
103	105
	106	+/* Text-based mount options passed to super.c */
	107	+static char nfs_root_options[256] __initdata = "";
	108	+
104	109	/* Address of NFS server */
105	110	static __be32 servaddr __initdata = 0;
106	111
107	112	/* Name of directory to mount */
108		-static char nfs_export_path[NFS_MAXPATHLEN + 1] __initdata = { 0, };
	113	+static char nfs_export_path[NFS_MAXPATHLEN + 1] __initdata = "";
109	114
	115	+/* server:export path string passed to super.c */
	116	+static char nfs_root_device[NFS_MAXPATHLEN + 1] __initdata = "";
	117	+
110	118	/* NFS-related data */
111	119	static struct nfs_mount_data nfs_data __initdata = { 0, };/* NFS mount info */
112	120	static int nfs_port __initdata = 0; /* Port to connect to for NFS */
...	...	@@ -537,7 +545,7 @@
537	545	* Get the NFS port numbers and file handle, and return the prepared 'data'
538	546	* argument for mount() if everything went OK. Return NULL otherwise.
539	547	*/
540		-void * __init nfs_root_data(void)
	548	+void * __init old_nfs_root_data(void)
541	549	{
542	550	if (root_nfs_init() < 0
543	551	\|\| root_nfs_ports() < 0
...	...	@@ -545,5 +553,167 @@
545	553	return NULL;
546	554	set_sockaddr((struct sockaddr_in *) &nfs_data.addr, servaddr, htons(nfs_port));
547	555	return (void*)&nfs_data;
	556	+}
	557	+
	558	+static int __init root_nfs_copy(char dest, const char src,
	559	+ const size_t destlen)
	560	+{
	561	+ if (strlcpy(dest, src, destlen) > destlen)
	562	+ return -1;
	563	+ return 0;
	564	+}
	565	+
	566	+static int __init root_nfs_cat(char dest, const char src,
	567	+ const size_t destlen)
	568	+{
	569	+ if (strlcat(dest, src, destlen) > destlen)
	570	+ return -1;
	571	+ return 0;
	572	+}
	573	+
	574	+/*
	575	+ * Parse out root export path and mount options from
	576	+ * passed-in string @incoming.
	577	+ *
	578	+ * Copy the export path into @exppath.
	579	+ */
	580	+static int __init root_nfs_parse_options(char incoming, char exppath,
	581	+ const size_t exppathlen)
	582	+{
	583	+ char *p;
	584	+
	585	+ /*
	586	+ * Set the NFS remote path
	587	+ */
	588	+ p = strsep(&incoming, ",");
	589	+ if (*p != '\0' && strcmp(p, "default") != 0)
	590	+ if (root_nfs_copy(exppath, p, exppathlen))
	591	+ return -1;
	592	+
	593	+ /*
	594	+ * @incoming now points to the rest of the string; if it
	595	+ * contains something, append it to our root options buffer
	596	+ */
	597	+ if (incoming != NULL && *incoming != '\0')
	598	+ if (root_nfs_cat(nfs_root_options, incoming,
	599	+ sizeof(nfs_root_options)))
	600	+ return -1;
	601	+
	602	+ /*
	603	+ * Possibly prepare for more options to be appended
	604	+ */
	605	+ if (nfs_root_options[0] != '\0' &&
	606	+ nfs_root_options[strlen(nfs_root_options)] != ',')
	607	+ if (root_nfs_cat(nfs_root_options, ",",
	608	+ sizeof(nfs_root_options)))
	609	+ return -1;
	610	+
	611	+ return 0;
	612	+}
	613	+
	614	+/*
	615	+ * Decode the export directory path name and NFS options from
	616	+ * the kernel command line. This has to be done late in order to
	617	+ * use a dynamically acquired client IP address for the remote
	618	+ * root directory path.
	619	+ *
	620	+ * Returns zero if successful; otherwise -1 is returned.
	621	+ */
	622	+static int __init root_nfs_data(char *cmdline)
	623	+{
	624	+ char addr_option[sizeof("nolock,addr=") + INET_ADDRSTRLEN + 1];
	625	+ int len, retval = -1;
	626	+ char *tmp = NULL;
	627	+ const size_t tmplen = sizeof(nfs_export_path);
	628	+
	629	+ tmp = kzalloc(tmplen, GFP_KERNEL);
	630	+ if (tmp == NULL)
	631	+ goto out_nomem;
	632	+ strcpy(tmp, NFS_ROOT);
	633	+
	634	+ if (root_server_path[0] != '\0') {
	635	+ dprintk("Root-NFS: DHCPv4 option 17: %s\n",
	636	+ root_server_path);
	637	+ if (root_nfs_parse_options(root_server_path, tmp, tmplen))
	638	+ goto out_optionstoolong;
	639	+ }
	640	+
	641	+ if (cmdline[0] != '\0') {
	642	+ dprintk("Root-NFS: nfsroot=%s\n", cmdline);
	643	+ if (root_nfs_parse_options(cmdline, tmp, tmplen))
	644	+ goto out_optionstoolong;
	645	+ }
	646	+
	647	+ /*
	648	+ * Append mandatory options for nfsroot so they override
	649	+ * what has come before
	650	+ */
	651	+ snprintf(addr_option, sizeof(addr_option), "nolock,addr=%pI4",
	652	+ &servaddr);
	653	+ if (root_nfs_cat(nfs_root_options, addr_option,
	654	+ sizeof(nfs_root_options)))
	655	+ goto out_optionstoolong;
	656	+
	657	+ /*
	658	+ * Set up nfs_root_device. For NFS mounts, this looks like
	659	+ *
	660	+ * server:/path
	661	+ *
	662	+ * At this point, utsname()->nodename contains our local
	663	+ * IP address or hostname, set by ipconfig. If "%s" exists
	664	+ * in tmp, substitute the nodename, then shovel the whole
	665	+ * mess into nfs_root_device.
	666	+ */
	667	+ len = snprintf(nfs_export_path, sizeof(nfs_export_path),
	668	+ tmp, utsname()->nodename);
	669	+ if (len > (int)sizeof(nfs_export_path))
	670	+ goto out_devnametoolong;
	671	+ len = snprintf(nfs_root_device, sizeof(nfs_root_device),
	672	+ "%pI4:%s", &servaddr, nfs_export_path);
	673	+ if (len > (int)sizeof(nfs_root_device))
	674	+ goto out_devnametoolong;
	675	+
	676	+ retval = 0;
	677	+
	678	+out:
	679	+ kfree(tmp);
	680	+ return retval;
	681	+out_nomem:
	682	+ printk(KERN_ERR "Root-NFS: could not allocate memory\n");
	683	+ goto out;
	684	+out_optionstoolong:
	685	+ printk(KERN_ERR "Root-NFS: mount options string too long\n");
	686	+ goto out;
	687	+out_devnametoolong:
	688	+ printk(KERN_ERR "Root-NFS: root device name too long.\n");
	689	+ goto out;
	690	+}
	691	+
	692	+/**
	693	+ * nfs_root_data - Return prepared 'data' for NFSROOT mount
	694	+ * @root_device: OUT: address of string containing NFSROOT device
	695	+ * @root_data: OUT: address of string containing NFSROOT mount options
	696	+ *
	697	+ * Returns zero and sets @root_device and @root_data if successful,
	698	+ * otherwise -1 is returned.
	699	+ */
	700	+int __init nfs_root_data(char root_device, char root_data)
	701	+{
	702	+#ifdef NFSROOT_DEBUG
	703	+ nfs_debug \|= NFSDBG_ROOT \| NFSDBG_MOUNT;
	704	+#endif /* NFSROOT_DEBUG */
	705	+
	706	+ servaddr = root_server_addr;
	707	+ if (servaddr == htonl(INADDR_NONE)) {
	708	+ printk(KERN_ERR "Root-NFS: no NFS server address\n");
	709	+ return -1;
	710	+ }
	711	+
	712	+ if (root_nfs_data(nfs_root_parms) < 0)
	713	+ return -1;
	714	+
	715	+ *root_device = nfs_root_device;
	716	+ *root_data = nfs_root_options;
	717	+ return 0;
548	718	}
...	...	@@ -364,6 +364,7 @@
364	364	extern void nfs_put_lock_context(struct nfs_lock_context *l_ctx);
365	365	extern u64 nfs_compat_user_ino64(u64 fileid);
366	366	extern void nfs_fattr_init(struct nfs_fattr *fattr);
	367	+extern unsigned long nfs_inc_attr_generation_counter(void);
367	368
368	369	extern struct nfs_fattr *nfs_alloc_fattr(void);
369	370
370	371
...	...	@@ -379,9 +380,12 @@
379	380	kfree(fh);
380	381	}
381	382
	383	+/*
	384	+ * linux/fs/nfs/nfsroot.c
	385	+ */
	386	+extern int nfs_root_data(char root_device, char root_data); /__init/
382	387	/* linux/net/ipv4/ipconfig.c: trims ip addr off front of name, too. */
383	388	extern __be32 root_nfs_parse_addr(char name); /__init*/
384		-extern unsigned long nfs_inc_attr_generation_counter(void);
385	389
386	390	/*
387	391	* linux/fs/nfs/file.c
...	...	@@ -583,10 +587,6 @@
583	587	ino ^= fileid >> (sizeof(u64)-sizeof(ino_t)) * 8;
584	588	return ino;
585	589	}
586		-
587		-/* NFS root */
588		-
589		-extern void * nfs_root_data(void);
590	590
591	591	#define nfs_wait_event(clnt, wq, condition) \
592	592	({ \
...	...	@@ -291,13 +291,13 @@
291	291	#ifdef CONFIG_ROOT_NFS
292	292	static int __init mount_nfs_root(void)
293	293	{
294		- void *data = nfs_root_data();
	294	+ char root_dev, root_data;
295	295
296		- create_dev("/dev/root", ROOT_DEV);
297		- if (data &&
298		- do_mount_root("/dev/root", "nfs", root_mountflags, data) == 0)
299		- return 1;
300		- return 0;
	296	+ if (nfs_root_data(&root_dev, &root_data) != 0)
	297	+ return 0;
	298	+ if (do_mount_root(root_dev, "nfs", root_mountflags, root_data) != 0)
	299	+ return 0;
	300	+ return 1;
301	301	}
302	302	#endif
303	303