From 55a975937d40cac582e981ddc8ed783b3dcc043c Mon Sep 17 00:00:00 2001 From: Trond Myklebust Date: Fri, 9 Jun 2006 09:34:19 -0400 Subject: [PATCH] NFS: Ensure the client submounts, when it crosses a server mountpoint. Signed-off-by: Trond Myklebust --- fs/nfs/Makefile | 3 +- fs/nfs/dir.c | 16 +++ fs/nfs/inode.c | 303 ++++++++++++++++++++++++++++++++++++++++- fs/nfs/namespace.c | 89 ++++++++++++ fs/nfs/nfs4_fs.h | 1 + fs/nfs/nfs4proc.c | 2 +- include/linux/nfs_fs.h | 9 ++ 7 files changed, 418 insertions(+), 5 deletions(-) create mode 100644 fs/nfs/namespace.c diff --git a/fs/nfs/Makefile b/fs/nfs/Makefile index ec61fd56a1a9..d9d494cee388 100644 --- a/fs/nfs/Makefile +++ b/fs/nfs/Makefile @@ -5,7 +5,8 @@ obj-$(CONFIG_NFS_FS) += nfs.o nfs-y := dir.o file.o inode.o nfs2xdr.o pagelist.o \ - proc.o read.o symlink.o unlink.o write.o + proc.o read.o symlink.o unlink.o write.o \ + namespace.o nfs-$(CONFIG_ROOT_NFS) += nfsroot.o mount_clnt.o nfs-$(CONFIG_NFS_V3) += nfs3proc.o nfs3xdr.o nfs-$(CONFIG_NFS_V3_ACL) += nfs3acl.o diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c index 1d3d8922a663..3ddda6f7ecc2 100644 --- a/fs/nfs/dir.c +++ b/fs/nfs/dir.c @@ -868,6 +868,17 @@ int nfs_is_exclusive_create(struct inode *dir, struct nameidata *nd) return (nd->intent.open.flags & O_EXCL) != 0; } +static inline int nfs_reval_fsid(struct inode *dir, + struct nfs_fh *fh, struct nfs_fattr *fattr) +{ + struct nfs_server *server = NFS_SERVER(dir); + + if (!nfs_fsid_equal(&server->fsid, &fattr->fsid)) + /* Revalidate fsid on root dir */ + return __nfs_revalidate_inode(server, dir->i_sb->s_root->d_inode); + return 0; +} + static struct dentry *nfs_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *nd) { struct dentry *res; @@ -900,6 +911,11 @@ static struct dentry *nfs_lookup(struct inode *dir, struct dentry * dentry, stru res = ERR_PTR(error); goto out_unlock; } + error = nfs_reval_fsid(dir, &fhandle, &fattr); + if (error < 0) { + res = ERR_PTR(error); + goto out_unlock; + } inode = nfs_fhget(dentry->d_sb, &fhandle, &fattr); res = (struct dentry *)inode; if (IS_ERR(res)) diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c index 1a809f6f8989..47167ab64f5b 100644 --- a/fs/nfs/inode.c +++ b/fs/nfs/inode.c @@ -221,6 +221,14 @@ nfs_block_size(unsigned long bsize, unsigned char *nrbitsp) return nfs_block_bits(bsize, nrbitsp); } +static inline void +nfs_super_set_maxbytes(struct super_block *sb, __u64 maxfilesize) +{ + sb->s_maxbytes = (loff_t)maxfilesize; + if (sb->s_maxbytes > MAX_LFS_FILESIZE || sb->s_maxbytes <= 0) + sb->s_maxbytes = MAX_LFS_FILESIZE; +} + /* * Obtain the root inode of the file system. */ @@ -331,9 +339,7 @@ nfs_sb_init(struct super_block *sb, rpc_authflavor_t authflavor) } server->backing_dev_info.ra_pages = server->rpages * NFS_MAX_READAHEAD; - sb->s_maxbytes = fsinfo.maxfilesize; - if (sb->s_maxbytes > MAX_LFS_FILESIZE) - sb->s_maxbytes = MAX_LFS_FILESIZE; + nfs_super_set_maxbytes(sb, fsinfo.maxfilesize); server->client->cl_intr = (server->flags & NFS_MOUNT_INTR) ? 1 : 0; server->client->cl_softrtry = (server->flags & NFS_MOUNT_SOFT) ? 1 : 0; @@ -877,6 +883,11 @@ nfs_fhget(struct super_block *sb, struct nfs_fh *fh, struct nfs_fattr *fattr) if (nfs_server_capable(inode, NFS_CAP_READDIRPLUS) && fattr->size <= NFS_LIMIT_READDIRPLUS) set_bit(NFS_INO_ADVISE_RDPLUS, &NFS_FLAGS(inode)); + /* Deal with crossing mountpoints */ + if (!nfs_fsid_equal(&NFS_SB(sb)->fsid, &fattr->fsid)) { + inode->i_op = &nfs_mountpoint_inode_operations; + inode->i_fop = NULL; + } } else if (S_ISLNK(inode->i_mode)) inode->i_op = &nfs_symlink_inode_operations; else @@ -1650,6 +1661,141 @@ static int nfs_update_inode(struct inode *inode, struct nfs_fattr *fattr) * File system information */ +/* + * 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. + */ +static 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); +} + +struct nfs_clone_mount { + const struct super_block *sb; + const struct dentry *dentry; + struct nfs_fh *fh; + struct nfs_fattr *fattr; +}; + +static struct super_block *nfs_clone_generic_sb(struct nfs_clone_mount *data, + struct super_block *(*clone_client)(struct nfs_server *, struct nfs_clone_mount *)) +{ + struct nfs_server *server; + struct nfs_server *parent = NFS_SB(data->sb); + struct super_block *sb = ERR_PTR(-EINVAL); + void *err = ERR_PTR(-ENOMEM); + struct inode *root_inode; + struct nfs_fsinfo fsinfo; + int len; + + server = kmalloc(sizeof(struct nfs_server), GFP_KERNEL); + if (server == NULL) + goto out_err; + memcpy(server, parent, sizeof(*server)); + len = strlen(parent->hostname) + 1; + server->hostname = kmalloc(len, GFP_KERNEL); + if (server->hostname == NULL) + goto free_server; + memcpy(server->hostname, parent->hostname, len); + server->fsid = data->fattr->fsid; + nfs_copy_fh(&server->fh, data->fh); + if (rpciod_up() != 0) + goto free_hostname; + + sb = clone_client(server, data); + if (IS_ERR((err = sb)) || sb->s_root) + goto kill_rpciod; + + sb->s_op = data->sb->s_op; + sb->s_blocksize = data->sb->s_blocksize; + sb->s_blocksize_bits = data->sb->s_blocksize_bits; + sb->s_maxbytes = data->sb->s_maxbytes; + + server->client_sys = server->client_acl = ERR_PTR(-EINVAL); + err = ERR_PTR(-ENOMEM); + server->io_stats = nfs_alloc_iostats(); + if (server->io_stats == NULL) + goto out_deactivate; + + server->client = rpc_clone_client(parent->client); + if (IS_ERR((err = server->client))) + goto out_deactivate; + if (!IS_ERR(parent->client_sys)) { + server->client_sys = rpc_clone_client(parent->client_sys); + if (IS_ERR((err = server->client_sys))) + goto out_deactivate; + } + if (!IS_ERR(parent->client_acl)) { + server->client_acl = rpc_clone_client(parent->client_acl); + if (IS_ERR((err = server->client_acl))) + goto out_deactivate; + } + root_inode = nfs_fhget(sb, data->fh, data->fattr); + if (!root_inode) + goto out_deactivate; + sb->s_root = d_alloc_root(root_inode); + if (!sb->s_root) + goto out_put_root; + fsinfo.fattr = data->fattr; + if (NFS_PROTO(root_inode)->fsinfo(server, data->fh, &fsinfo) == 0) + nfs_super_set_maxbytes(sb, fsinfo.maxfilesize); + sb->s_root->d_op = server->rpc_ops->dentry_ops; + sb->s_flags |= MS_ACTIVE; + return sb; +out_put_root: + iput(root_inode); +out_deactivate: + up_write(&sb->s_umount); + deactivate_super(sb); + return (struct super_block *)err; +kill_rpciod: + rpciod_down(); +free_hostname: + kfree(server->hostname); +free_server: + kfree(server); +out_err: + return (struct super_block *)err; +} + static int nfs_set_super(struct super_block *s, void *data) { s->s_fs_info = data; @@ -1807,6 +1953,31 @@ static struct file_system_type nfs_fs_type = { .fs_flags = FS_ODD_RENAME|FS_REVAL_DOT|FS_BINARY_MOUNTDATA, }; +static struct super_block *nfs_clone_client(struct nfs_server *server, struct nfs_clone_mount *data) +{ + struct super_block *sb; + + sb = sget(&nfs_fs_type, nfs_compare_super, nfs_set_super, server); + if (!IS_ERR(sb) && sb->s_root == NULL && !(server->flags & NFS_MOUNT_NONLM)) + lockd_up(); + return sb; +} + +static struct super_block *nfs_clone_nfs_sb(struct file_system_type *fs_type, + int flags, const char *dev_name, void *raw_data) +{ + struct nfs_clone_mount *data = raw_data; + return nfs_clone_generic_sb(data, nfs_clone_client); +} + +static struct file_system_type clone_nfs_fs_type = { + .owner = THIS_MODULE, + .name = "nfs", + .get_sb = nfs_clone_nfs_sb, + .kill_sb = nfs_kill_super, + .fs_flags = FS_ODD_RENAME|FS_REVAL_DOT|FS_BINARY_MOUNTDATA, +}; + #ifdef CONFIG_NFS_V4 static void nfs4_clear_inode(struct inode *); @@ -2156,6 +2327,75 @@ static int param_set_idmap_timeout(const char *val, struct kernel_param *kp) module_param_call(idmap_cache_timeout, param_set_idmap_timeout, param_get_int, &nfs_idmap_cache_timeout, 0644); +/* Constructs the SERVER-side path */ +static inline char *nfs4_path(const struct dentry *dentry, char *buffer, ssize_t buflen) +{ + return nfs_path(NFS_SB(dentry->d_sb)->mnt_path, dentry, buffer, buflen); +} + +static inline char *nfs4_dup_path(const struct dentry *dentry) +{ + char *page = (char *) __get_free_page(GFP_USER); + char *path; + + path = nfs4_path(dentry, page, PAGE_SIZE); + if (!IS_ERR(path)) { + int len = PAGE_SIZE + page - path; + char *tmp = path; + + path = kmalloc(len, GFP_KERNEL); + if (path) + memcpy(path, tmp, len); + else + path = ERR_PTR(-ENOMEM); + } + free_page((unsigned long)page); + return path; +} + +static struct super_block *nfs4_clone_client(struct nfs_server *server, struct nfs_clone_mount *data) +{ + const struct dentry *dentry = data->dentry; + struct nfs4_client *clp = server->nfs4_state; + struct super_block *sb; + + server->mnt_path = nfs4_dup_path(dentry); + if (IS_ERR(server->mnt_path)) { + sb = (struct super_block *)server->mnt_path; + goto err; + } + sb = sget(&nfs4_fs_type, nfs4_compare_super, nfs_set_super, server); + if (IS_ERR(sb) || sb->s_root) + goto free_path; + nfs4_server_capabilities(server, &server->fh); + + down_write(&clp->cl_sem); + atomic_inc(&clp->cl_count); + list_add_tail(&server->nfs4_siblings, &clp->cl_superblocks); + up_write(&clp->cl_sem); + return sb; +free_path: + kfree(server->mnt_path); +err: + server->mnt_path = NULL; + return sb; +} + +static struct super_block *nfs_clone_nfs4_sb(struct file_system_type *fs_type, + int flags, const char *dev_name, void *raw_data) +{ + struct nfs_clone_mount *data = raw_data; + return nfs_clone_generic_sb(data, nfs4_clone_client); +} + +static struct file_system_type clone_nfs4_fs_type = { + .owner = THIS_MODULE, + .name = "nfs", + .get_sb = nfs_clone_nfs4_sb, + .kill_sb = nfs4_kill_super, + .fs_flags = FS_ODD_RENAME|FS_REVAL_DOT|FS_BINARY_MOUNTDATA, +}; + #define nfs4_init_once(nfsi) \ do { \ INIT_LIST_HEAD(&(nfsi)->open_states); \ @@ -2183,12 +2423,69 @@ static inline void unregister_nfs4fs(void) nfs_unregister_sysctl(); } #else +#define nfs4_clone_client(a,b) ERR_PTR(-EINVAL) #define nfs4_init_once(nfsi) \ do { } while (0) #define register_nfs4fs() (0) #define unregister_nfs4fs() #endif +static inline char *nfs_devname(const struct vfsmount *mnt_parent, + const struct dentry *dentry, + char *buffer, ssize_t buflen) +{ + return nfs_path(mnt_parent->mnt_devname, dentry, buffer, buflen); +} + +/** + * 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; + switch (NFS_SB(mnt_parent->mnt_sb)->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); + break; + default: + BUG(); + } +free_page: + free_page((unsigned long)page); +out: + dprintk("%s: done\n", __FUNCTION__); + return mnt; +} + extern int nfs_init_nfspagecache(void); extern void nfs_destroy_nfspagecache(void); extern int nfs_init_readpagecache(void); diff --git a/fs/nfs/namespace.c b/fs/nfs/namespace.c new file mode 100644 index 000000000000..a155505c36f1 --- /dev/null +++ b/fs/nfs/namespace.c @@ -0,0 +1,89 @@ +/* + * linux/fs/nfs/namespace.c + * + * Copyright (C) 2005 Trond Myklebust + * + * NFS namespace + */ + +#include + +#include +#include +#include +#include +#include +#include +#include + +#define NFSDBG_FACILITY NFSDBG_VFS + +/* + * nfs_follow_mountpoint - handle crossing a mountpoint on the server + * @dentry - dentry of mountpoint + * @nd - nameidata info + * + * 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. + */ +static void * nfs_follow_mountpoint(struct dentry *dentry, struct nameidata *nd) +{ + struct vfsmount *mnt; + struct nfs_server *server = NFS_SERVER(dentry->d_inode); + struct dentry *parent; + struct nfs_fh fh; + struct nfs_fattr fattr; + int err; + + BUG_ON(IS_ROOT(dentry)); + dprintk("%s: enter\n", __FUNCTION__); + dput(nd->dentry); + nd->dentry = dget(dentry); + if (d_mountpoint(nd->dentry)) + goto out_follow; + /* Look it up again */ + parent = dget_parent(nd->dentry); + err = server->rpc_ops->lookup(parent->d_inode, &nd->dentry->d_name, &fh, &fattr); + dput(parent); + if (err != 0) + goto out_err; + + mnt = nfs_do_submount(nd->mnt, nd->dentry, &fh, &fattr); + err = PTR_ERR(mnt); + if (IS_ERR(mnt)) + goto out_err; + + mntget(mnt); + err = do_add_mount(mnt, nd, nd->mnt->mnt_flags, NULL); + if (err < 0) { + mntput(mnt); + if (err == -EBUSY) + goto out_follow; + goto out_err; + } + mntput(nd->mnt); + dput(nd->dentry); + nd->mnt = mnt; + nd->dentry = dget(mnt->mnt_root); +out: + dprintk("%s: done, returned %d\n", __FUNCTION__, err); + return ERR_PTR(err); +out_err: + path_release(nd); + goto out; +out_follow: + while(d_mountpoint(nd->dentry) && follow_down(&nd->mnt, &nd->dentry)) + ; + err = 0; + goto out; +} + +struct inode_operations nfs_mountpoint_inode_operations = { + .follow_link = nfs_follow_mountpoint, + .getattr = nfs_getattr, +}; diff --git a/fs/nfs/nfs4_fs.h b/fs/nfs/nfs4_fs.h index 0f5e4e7cddec..307832fd1a49 100644 --- a/fs/nfs/nfs4_fs.h +++ b/fs/nfs/nfs4_fs.h @@ -217,6 +217,7 @@ extern int nfs4_proc_renew(struct nfs4_client *, struct rpc_cred *); extern int nfs4_do_close(struct inode *inode, struct nfs4_state *state); extern struct dentry *nfs4_atomic_open(struct inode *, struct dentry *, struct nameidata *); extern int nfs4_open_revalidate(struct inode *, struct dentry *, int, struct nameidata *); +extern int nfs4_server_capabilities(struct nfs_server *server, struct nfs_fh *fhandle); extern struct nfs4_state_recovery_ops nfs4_reboot_recovery_ops; extern struct nfs4_state_recovery_ops nfs4_network_partition_recovery_ops; diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c index ef4c6cccf958..308407205e6c 100644 --- a/fs/nfs/nfs4proc.c +++ b/fs/nfs/nfs4proc.c @@ -1331,7 +1331,7 @@ static int _nfs4_server_capabilities(struct nfs_server *server, struct nfs_fh *f return status; } -static int nfs4_server_capabilities(struct nfs_server *server, struct nfs_fh *fhandle) +int nfs4_server_capabilities(struct nfs_server *server, struct nfs_fh *fhandle) { struct nfs4_exception exception = { }; int err; diff --git a/include/linux/nfs_fs.h b/include/linux/nfs_fs.h index 6763a0089ee4..0ce8704732c2 100644 --- a/include/linux/nfs_fs.h +++ b/include/linux/nfs_fs.h @@ -313,6 +313,10 @@ extern void nfs_end_data_update(struct inode *); extern struct nfs_open_context *get_nfs_open_context(struct nfs_open_context *ctx); extern void put_nfs_open_context(struct nfs_open_context *ctx); extern struct nfs_open_context *nfs_find_open_context(struct inode *inode, struct rpc_cred *cred, int mode); +extern struct vfsmount *nfs_do_submount(const struct vfsmount *mnt_parent, + const struct dentry *dentry, + struct nfs_fh *fh, + struct nfs_fattr *fattr); /* linux/net/ipv4/ipconfig.c: trims ip addr off front of name, too. */ extern u32 root_nfs_parse_addr(char *name); /*__init*/ @@ -398,6 +402,11 @@ extern void nfs_unregister_sysctl(void); #define nfs_unregister_sysctl() do { } while(0) #endif +/* + * linux/fs/nfs/namespace.c + */ +extern struct inode_operations nfs_mountpoint_inode_operations; + /* * linux/fs/nfs/unlink.c */