diff options
Diffstat (limited to 'fs/nfs/namespace.c')
| -rw-r--r-- | fs/nfs/namespace.c | 335 |
1 files changed, 335 insertions, 0 deletions
diff --git a/fs/nfs/namespace.c b/fs/nfs/namespace.c new file mode 100644 index 00000000..d51868e5 --- /dev/null +++ b/fs/nfs/namespace.c @@ -0,0 +1,335 @@ +/* + * linux/fs/nfs/namespace.c + * + * Copyright (C) 2005 Trond Myklebust <Trond.Myklebust@netapp.com> + * - Modified by David Howells <dhowells@redhat.com> + * + * NFS namespace + */ + +#include <linux/dcache.h> +#include <linux/gfp.h> +#include <linux/mount.h> +#include <linux/namei.h> +#include <linux/nfs_fs.h> +#include <linux/string.h> +#include <linux/sunrpc/clnt.h> +#include <linux/vfs.h> +#include <linux/sunrpc/gss_api.h> +#include "internal.h" + +#define NFSDBG_FACILITY NFSDBG_VFS + +static void nfs_expire_automounts(struct work_struct *work); + +static LIST_HEAD(nfs_automount_list); +static DECLARE_DELAYED_WORK(nfs_automount_task, nfs_expire_automounts); +int nfs_mountpoint_expiry_timeout = 500 * HZ; + +static struct vfsmount *nfs_do_submount(struct dentry *dentry, + struct nfs_fh *fh, + struct nfs_fattr *fattr, + rpc_authflavor_t authflavor); + +/* + * nfs_path - reconstruct the path given an arbitrary dentry + * @base - used to return pointer to the end of devname part of path + * @dentry - pointer to dentry + * @buffer - result buffer + * @buflen - length of buffer + * + * Helper function for constructing the server pathname + * by 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 + * and in generating /proc/mounts and friends. + */ +char *nfs_path(char **p, struct dentry *dentry, char *buffer, ssize_t buflen) +{ + char *end; + int namelen; + unsigned seq; + const char *base; + +rename_retry: + end = buffer+buflen; + *--end = '\0'; + buflen--; + + seq = read_seqbegin(&rename_lock); + rcu_read_lock(); + while (1) { + spin_lock(&dentry->d_lock); + if (IS_ROOT(dentry)) + break; + namelen = dentry->d_name.len; + buflen -= namelen + 1; + if (buflen < 0) + goto Elong_unlock; + end -= namelen; + memcpy(end, dentry->d_name.name, namelen); + *--end = '/'; + spin_unlock(&dentry->d_lock); + dentry = dentry->d_parent; + } + if (read_seqretry(&rename_lock, seq)) { + spin_unlock(&dentry->d_lock); + rcu_read_unlock(); + goto rename_retry; + } + if (*end != '/') { + if (--buflen < 0) { + spin_unlock(&dentry->d_lock); + rcu_read_unlock(); + goto Elong; + } + *--end = '/'; + } + *p = end; + base = dentry->d_fsdata; + if (!base) { + spin_unlock(&dentry->d_lock); + rcu_read_unlock(); + WARN_ON(1); + return end; + } + namelen = strlen(base); + /* Strip off excess slashes in base string */ + while (namelen > 0 && base[namelen - 1] == '/') + namelen--; + buflen -= namelen; + if (buflen < 0) { + spin_unlock(&dentry->d_lock); + rcu_read_unlock(); + goto Elong; + } + end -= namelen; + memcpy(end, base, namelen); + spin_unlock(&dentry->d_lock); + rcu_read_unlock(); + return end; +Elong_unlock: + spin_unlock(&dentry->d_lock); + rcu_read_unlock(); + if (read_seqretry(&rename_lock, seq)) + goto rename_retry; +Elong: + return ERR_PTR(-ENAMETOOLONG); +} + +#ifdef CONFIG_NFS_V4 +rpc_authflavor_t nfs_find_best_sec(struct nfs4_secinfo_flavors *flavors) +{ + struct gss_api_mech *mech; + struct xdr_netobj oid; + int i; + rpc_authflavor_t pseudoflavor = RPC_AUTH_UNIX; + + for (i = 0; i < flavors->num_flavors; i++) { + struct nfs4_secinfo_flavor *flavor; + flavor = &flavors->flavors[i]; + + if (flavor->flavor == RPC_AUTH_NULL || flavor->flavor == RPC_AUTH_UNIX) { + pseudoflavor = flavor->flavor; + break; + } else if (flavor->flavor == RPC_AUTH_GSS) { + oid.len = flavor->gss.sec_oid4.len; + oid.data = flavor->gss.sec_oid4.data; + mech = gss_mech_get_by_OID(&oid); + if (!mech) + continue; + pseudoflavor = gss_svc_to_pseudoflavor(mech, flavor->gss.service); + gss_mech_put(mech); + break; + } + } + + return pseudoflavor; +} + +static struct rpc_clnt *nfs_lookup_mountpoint(struct inode *dir, + struct qstr *name, + struct nfs_fh *fh, + struct nfs_fattr *fattr) +{ + int err; + + if (NFS_PROTO(dir)->version == 4) + return nfs4_proc_lookup_mountpoint(dir, name, fh, fattr); + + err = NFS_PROTO(dir)->lookup(NFS_SERVER(dir)->client, dir, name, fh, fattr); + if (err) + return ERR_PTR(err); + return rpc_clone_client(NFS_SERVER(dir)->client); +} +#else /* CONFIG_NFS_V4 */ +static inline struct rpc_clnt *nfs_lookup_mountpoint(struct inode *dir, + struct qstr *name, + struct nfs_fh *fh, + struct nfs_fattr *fattr) +{ + int err = NFS_PROTO(dir)->lookup(NFS_SERVER(dir)->client, dir, name, fh, fattr); + if (err) + return ERR_PTR(err); + return rpc_clone_client(NFS_SERVER(dir)->client); +} +#endif /* CONFIG_NFS_V4 */ + +/* + * nfs_d_automount - Handle crossing a mountpoint on the server + * @path - The mountpoint + * + * When we encounter a mountpoint on the server, we want to set up + * a mountpoint on the client too, to prevent inode numbers from + * colliding, and to allow "df" to work properly. + * On NFSv4, we also want to allow for the fact that different + * filesystems may be migrated to different servers in a failover + * situation, and that different filesystems may want to use + * different security flavours. + */ +struct vfsmount *nfs_d_automount(struct path *path) +{ + struct vfsmount *mnt; + struct dentry *parent; + struct nfs_fh *fh = NULL; + struct nfs_fattr *fattr = NULL; + struct rpc_clnt *client; + + dprintk("--> nfs_d_automount()\n"); + + mnt = ERR_PTR(-ESTALE); + if (IS_ROOT(path->dentry)) + goto out_nofree; + + mnt = ERR_PTR(-ENOMEM); + fh = nfs_alloc_fhandle(); + fattr = nfs_alloc_fattr(); + if (fh == NULL || fattr == NULL) + goto out; + + dprintk("%s: enter\n", __func__); + + /* Look it up again to get its attributes */ + parent = dget_parent(path->dentry); + client = nfs_lookup_mountpoint(parent->d_inode, &path->dentry->d_name, fh, fattr); + dput(parent); + if (IS_ERR(client)) { + mnt = ERR_CAST(client); + goto out; + } + + if (fattr->valid & NFS_ATTR_FATTR_V4_REFERRAL) + mnt = nfs_do_refmount(client, path->dentry); + else + mnt = nfs_do_submount(path->dentry, fh, fattr, client->cl_auth->au_flavor); + rpc_shutdown_client(client); + + if (IS_ERR(mnt)) + goto out; + + dprintk("%s: done, success\n", __func__); + mntget(mnt); /* prevent immediate expiration */ + mnt_set_expiry(mnt, &nfs_automount_list); + schedule_delayed_work(&nfs_automount_task, nfs_mountpoint_expiry_timeout); + +out: + nfs_free_fattr(fattr); + nfs_free_fhandle(fh); +out_nofree: + if (IS_ERR(mnt)) + dprintk("<-- %s(): error %ld\n", __func__, PTR_ERR(mnt)); + else + dprintk("<-- %s() = %p\n", __func__, mnt); + return mnt; +} + +const struct inode_operations nfs_mountpoint_inode_operations = { + .getattr = nfs_getattr, +}; + +const struct inode_operations nfs_referral_inode_operations = { +}; + +static void nfs_expire_automounts(struct work_struct *work) +{ + struct list_head *list = &nfs_automount_list; + + mark_mounts_for_expiry(list); + if (!list_empty(list)) + schedule_delayed_work(&nfs_automount_task, nfs_mountpoint_expiry_timeout); +} + +void nfs_release_automount_timer(void) +{ + if (list_empty(&nfs_automount_list)) + cancel_delayed_work(&nfs_automount_task); +} + +/* + * Clone a mountpoint of the appropriate type + */ +static struct vfsmount *nfs_do_clone_mount(struct nfs_server *server, + const char *devname, + struct nfs_clone_mount *mountdata) +{ +#ifdef CONFIG_NFS_V4 + struct vfsmount *mnt = ERR_PTR(-EINVAL); + switch (server->nfs_client->rpc_ops->version) { + case 2: + case 3: + mnt = vfs_kern_mount(&nfs_xdev_fs_type, 0, devname, mountdata); + break; + case 4: + mnt = vfs_kern_mount(&nfs4_xdev_fs_type, 0, devname, mountdata); + } + return mnt; +#else + return vfs_kern_mount(&nfs_xdev_fs_type, 0, devname, mountdata); +#endif +} + +/** + * nfs_do_submount - set up mountpoint when crossing a filesystem boundary + * @dentry - parent directory + * @fh - filehandle for new root dentry + * @fattr - attributes for new root inode + * @authflavor - security flavor to use when performing the mount + * + */ +static struct vfsmount *nfs_do_submount(struct dentry *dentry, + struct nfs_fh *fh, + struct nfs_fattr *fattr, + rpc_authflavor_t authflavor) +{ + struct nfs_clone_mount mountdata = { + .sb = dentry->d_sb, + .dentry = dentry, + .fh = fh, + .fattr = fattr, + .authflavor = authflavor, + }; + struct vfsmount *mnt = ERR_PTR(-ENOMEM); + char *page = (char *) __get_free_page(GFP_USER); + char *devname; + + dprintk("--> nfs_do_submount()\n"); + + dprintk("%s: submounting on %s/%s\n", __func__, + dentry->d_parent->d_name.name, + dentry->d_name.name); + if (page == NULL) + goto out; + devname = nfs_devname(dentry, page, PAGE_SIZE); + mnt = (struct vfsmount *)devname; + if (IS_ERR(devname)) + goto free_page; + mnt = nfs_do_clone_mount(NFS_SB(dentry->d_sb), devname, &mountdata); +free_page: + free_page((unsigned long)page); +out: + dprintk("%s: done\n", __func__); + + dprintk("<-- nfs_do_submount() = %p\n", mnt); + return mnt; +} |