diff options
Diffstat (limited to 'fs/nfs/namespace.c')
-rw-r--r-- | fs/nfs/namespace.c | 112 |
1 files changed, 111 insertions, 1 deletions
diff --git a/fs/nfs/namespace.c b/fs/nfs/namespace.c index 8ca44b7b25c3..19b98ca468eb 100644 --- a/fs/nfs/namespace.c +++ b/fs/nfs/namespace.c @@ -15,15 +15,64 @@ #include <linux/string.h> #include <linux/sunrpc/clnt.h> #include <linux/vfs.h> +#include "internal.h" #define NFSDBG_FACILITY NFSDBG_VFS -LIST_HEAD(nfs_automount_list); static void nfs_expire_automounts(void *list); + +LIST_HEAD(nfs_automount_list); static DECLARE_WORK(nfs_automount_task, nfs_expire_automounts, &nfs_automount_list); int nfs_mountpoint_expiry_timeout = 500 * HZ; /* + * nfs_path - reconstruct the path given an arbitrary dentry + * @base - arbitrary string to prepend to the path + * @dentry - pointer to dentry + * @buffer - result buffer + * @buflen - length of buffer + * + * Helper function for constructing the path from the + * root dentry to an arbitrary hashed dentry. + * + * This is mainly for use in figuring out the path on the + * server side when automounting on top of an existing partition. + */ +char *nfs_path(const char *base, const struct dentry *dentry, + char *buffer, ssize_t buflen) +{ + char *end = buffer+buflen; + int namelen; + + *--end = '\0'; + buflen--; + spin_lock(&dcache_lock); + while (!IS_ROOT(dentry)) { + namelen = dentry->d_name.len; + buflen -= namelen + 1; + if (buflen < 0) + goto Elong; + end -= namelen; + memcpy(end, dentry->d_name.name, namelen); + *--end = '/'; + dentry = dentry->d_parent; + } + spin_unlock(&dcache_lock); + namelen = strlen(base); + /* Strip off excess slashes in base string */ + while (namelen > 0 && base[namelen - 1] == '/') + namelen--; + buflen -= namelen; + if (buflen < 0) + goto Elong; + end -= namelen; + memcpy(end, base, namelen); + return end; +Elong: + return ERR_PTR(-ENAMETOOLONG); +} + +/* * nfs_follow_mountpoint - handle crossing a mountpoint on the server * @dentry - dentry of mountpoint * @nd - nameidata info @@ -117,3 +166,64 @@ void nfs_release_automount_timer(void) flush_scheduled_work(); } } + +/* + * Clone a mountpoint of the appropriate type + */ +static struct vfsmount *nfs_do_clone_mount(struct nfs_server *server, char *devname, + struct nfs_clone_mount *mountdata) +{ +#ifdef CONFIG_NFS_V4 + struct vfsmount *mnt = NULL; + switch (server->rpc_ops->version) { + case 2: + case 3: + mnt = vfs_kern_mount(&clone_nfs_fs_type, 0, devname, mountdata); + break; + case 4: + mnt = vfs_kern_mount(&clone_nfs4_fs_type, 0, devname, mountdata); + } + return mnt; +#else + return vfs_kern_mount(&clone_nfs_fs_type, 0, devname, mountdata); +#endif +} + +/** + * nfs_do_submount - set up mountpoint when crossing a filesystem boundary + * @mnt_parent - mountpoint of parent directory + * @dentry - parent directory + * @fh - filehandle for new root dentry + * @fattr - attributes for new root inode + * + */ +struct vfsmount *nfs_do_submount(const struct vfsmount *mnt_parent, + const struct dentry *dentry, struct nfs_fh *fh, + struct nfs_fattr *fattr) +{ + struct nfs_clone_mount mountdata = { + .sb = mnt_parent->mnt_sb, + .dentry = dentry, + .fh = fh, + .fattr = fattr, + }; + struct vfsmount *mnt = ERR_PTR(-ENOMEM); + char *page = (char *) __get_free_page(GFP_USER); + char *devname; + + dprintk("%s: submounting on %s/%s\n", __FUNCTION__, + dentry->d_parent->d_name.name, + dentry->d_name.name); + if (page == NULL) + goto out; + devname = nfs_devname(mnt_parent, dentry, page, PAGE_SIZE); + mnt = (struct vfsmount *)devname; + if (IS_ERR(devname)) + goto free_page; + mnt = nfs_do_clone_mount(NFS_SB(mnt_parent->mnt_sb), devname, &mountdata); +free_page: + free_page((unsigned long)page); +out: + dprintk("%s: done\n", __FUNCTION__); + return mnt; +} |