From 56463e50d1fc3f070492434cea6303b35ea000de Mon Sep 17 00:00:00 2001 From: Chuck Lever Date: Fri, 17 Sep 2010 10:54:37 -0400 Subject: 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=,wsize= As before, however, no version/protocol negotiation with the server is done. Signed-off-by: Chuck Lever Signed-off-by: Trond Myklebust --- 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 169b67907a65..cb4a6bdca871 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 #include @@ -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 508f8cf6da37..2a18f1582fa4 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 02e3ca4fc527..52387f14f9b4 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 -- cgit v1.2.3-58-ga151