NFS: Ensure the client submounts, when it crosses a server mountpoint.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index 1a809f6..47167ab 100644
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -221,6 +221,14 @@
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 @@
}
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 @@
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 @@
* 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 @@
.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 @@
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 @@
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);