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@xxxxxxxxxx>
---
fs/nfs/nfsroot.c | 182 ++++++++++++++++++++++++++++++++++++++++++++++--
include/linux/nfs_fs.h | 10 +--
init/do_mounts.c | 12 ++-
3 files changed, 187 insertions(+), 17 deletions(-)
diff --git a/fs/nfs/nfsroot.c b/fs/nfs/nfsroot.c
index 169b679..cb4a6bd 100644
--- a/fs/nfs/nfsroot.c
+++ b/fs/nfs/nfsroot.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>
@@ -101,11 +103,17 @@
/* 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 */
@@ -537,7 +545,7 @@ out:
* 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
@@ -546,3 +554,165 @@ void * __init nfs_root_data(void)
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;
+}
diff --git a/include/linux/nfs_fs.h b/include/linux/nfs_fs.h
index 508f8cf..2a18f15 100644
--- a/include/linux/nfs_fs.h
+++ b/include/linux/nfs_fs.h
@@ -364,6 +364,7 @@ extern struct nfs_lock_context *nfs_get_lock_context(struct nfs_open_context *ct
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 @@ static inline void nfs_free_fhandle(const struct nfs_fh *fh)
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
@@ -584,10 +588,6 @@ nfs_fileid_to_ino_t(u64 fileid)
return ino;
}
-/* NFS root */
-
-extern void * nfs_root_data(void);
-
#define nfs_wait_event(clnt, wq, condition) \
({ \
int __retval = wait_event_killable(wq, condition); \
diff --git a/init/do_mounts.c b/init/do_mounts.c
index 02e3ca4..52387f1 100644
--- a/init/do_mounts.c
+++ b/init/do_mounts.c
@@ -291,13 +291,13 @@ out:
#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
--
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