diff options
Diffstat (limited to 'net/sunrpc/rpc_pipe.c')
-rw-r--r-- | net/sunrpc/rpc_pipe.c | 942 |
1 files changed, 942 insertions, 0 deletions
diff --git a/net/sunrpc/rpc_pipe.c b/net/sunrpc/rpc_pipe.c new file mode 100644 index 0000000..23a2b8f --- /dev/null +++ b/net/sunrpc/rpc_pipe.c @@ -0,0 +1,942 @@ +/* + * net/sunrpc/rpc_pipe.c + * + * Userland/kernel interface for rpcauth_gss. + * Code shamelessly plagiarized from fs/nfsd/nfsctl.c + * and fs/sysfs/inode.c + * + * Copyright (c) 2002, Trond Myklebust <trond.myklebust@fys.uio.no> + * + */ +#include <linux/module.h> +#include <linux/slab.h> +#include <linux/string.h> +#include <linux/pagemap.h> +#include <linux/mount.h> +#include <linux/namei.h> +#include <linux/fsnotify.h> +#include <linux/kernel.h> + +#include <asm/ioctls.h> +#include <linux/fs.h> +#include <linux/poll.h> +#include <linux/wait.h> +#include <linux/seq_file.h> + +#include <linux/sunrpc/clnt.h> +#include <linux/workqueue.h> +#include <linux/sunrpc/rpc_pipe_fs.h> + +static struct vfsmount *rpc_mount __read_mostly; +static int rpc_mount_count; + +static struct file_system_type rpc_pipe_fs_type; + + +static struct kmem_cache *rpc_inode_cachep __read_mostly; + +#define RPC_UPCALL_TIMEOUT (30*HZ) + +static void rpc_purge_list(struct rpc_inode *rpci, struct list_head *head, + void (*destroy_msg)(struct rpc_pipe_msg *), int err) +{ + struct rpc_pipe_msg *msg; + + if (list_empty(head)) + return; + do { + msg = list_entry(head->next, struct rpc_pipe_msg, list); + list_del(&msg->list); + msg->errno = err; + destroy_msg(msg); + } while (!list_empty(head)); + wake_up(&rpci->waitq); +} + +static void +rpc_timeout_upcall_queue(struct work_struct *work) +{ + LIST_HEAD(free_list); + struct rpc_inode *rpci = + container_of(work, struct rpc_inode, queue_timeout.work); + struct inode *inode = &rpci->vfs_inode; + void (*destroy_msg)(struct rpc_pipe_msg *); + + spin_lock(&inode->i_lock); + if (rpci->ops == NULL) { + spin_unlock(&inode->i_lock); + return; + } + destroy_msg = rpci->ops->destroy_msg; + if (rpci->nreaders == 0) { + list_splice_init(&rpci->pipe, &free_list); + rpci->pipelen = 0; + } + spin_unlock(&inode->i_lock); + rpc_purge_list(rpci, &free_list, destroy_msg, -ETIMEDOUT); +} + +/** + * rpc_queue_upcall + * @inode: inode of upcall pipe on which to queue given message + * @msg: message to queue + * + * Call with an @inode created by rpc_mkpipe() to queue an upcall. + * A userspace process may then later read the upcall by performing a + * read on an open file for this inode. It is up to the caller to + * initialize the fields of @msg (other than @msg->list) appropriately. + */ +int +rpc_queue_upcall(struct inode *inode, struct rpc_pipe_msg *msg) +{ + struct rpc_inode *rpci = RPC_I(inode); + int res = -EPIPE; + + spin_lock(&inode->i_lock); + if (rpci->ops == NULL) + goto out; + if (rpci->nreaders) { + list_add_tail(&msg->list, &rpci->pipe); + rpci->pipelen += msg->len; + res = 0; + } else if (rpci->flags & RPC_PIPE_WAIT_FOR_OPEN) { + if (list_empty(&rpci->pipe)) + queue_delayed_work(rpciod_workqueue, + &rpci->queue_timeout, + RPC_UPCALL_TIMEOUT); + list_add_tail(&msg->list, &rpci->pipe); + rpci->pipelen += msg->len; + res = 0; + } +out: + spin_unlock(&inode->i_lock); + wake_up(&rpci->waitq); + return res; +} +EXPORT_SYMBOL(rpc_queue_upcall); + +static inline void +rpc_inode_setowner(struct inode *inode, void *private) +{ + RPC_I(inode)->private = private; +} + +static void +rpc_close_pipes(struct inode *inode) +{ + struct rpc_inode *rpci = RPC_I(inode); + struct rpc_pipe_ops *ops; + + mutex_lock(&inode->i_mutex); + ops = rpci->ops; + if (ops != NULL) { + LIST_HEAD(free_list); + + spin_lock(&inode->i_lock); + rpci->nreaders = 0; + list_splice_init(&rpci->in_upcall, &free_list); + list_splice_init(&rpci->pipe, &free_list); + rpci->pipelen = 0; + rpci->ops = NULL; + spin_unlock(&inode->i_lock); + rpc_purge_list(rpci, &free_list, ops->destroy_msg, -EPIPE); + rpci->nwriters = 0; + if (ops->release_pipe) + ops->release_pipe(inode); + cancel_delayed_work_sync(&rpci->queue_timeout); + } + rpc_inode_setowner(inode, NULL); + mutex_unlock(&inode->i_mutex); +} + +static struct inode * +rpc_alloc_inode(struct super_block *sb) +{ + struct rpc_inode *rpci; + rpci = (struct rpc_inode *)kmem_cache_alloc(rpc_inode_cachep, GFP_KERNEL); + if (!rpci) + return NULL; + return &rpci->vfs_inode; +} + +static void +rpc_destroy_inode(struct inode *inode) +{ + kmem_cache_free(rpc_inode_cachep, RPC_I(inode)); +} + +static int +rpc_pipe_open(struct inode *inode, struct file *filp) +{ + struct rpc_inode *rpci = RPC_I(inode); + int res = -ENXIO; + + mutex_lock(&inode->i_mutex); + if (rpci->ops != NULL) { + if (filp->f_mode & FMODE_READ) + rpci->nreaders ++; + if (filp->f_mode & FMODE_WRITE) + rpci->nwriters ++; + res = 0; + } + mutex_unlock(&inode->i_mutex); + return res; +} + +static int +rpc_pipe_release(struct inode *inode, struct file *filp) +{ + struct rpc_inode *rpci = RPC_I(inode); + struct rpc_pipe_msg *msg; + + mutex_lock(&inode->i_mutex); + if (rpci->ops == NULL) + goto out; + msg = (struct rpc_pipe_msg *)filp->private_data; + if (msg != NULL) { + spin_lock(&inode->i_lock); + msg->errno = -EAGAIN; + list_del(&msg->list); + spin_unlock(&inode->i_lock); + rpci->ops->destroy_msg(msg); + } + if (filp->f_mode & FMODE_WRITE) + rpci->nwriters --; + if (filp->f_mode & FMODE_READ) { + rpci->nreaders --; + if (rpci->nreaders == 0) { + LIST_HEAD(free_list); + spin_lock(&inode->i_lock); + list_splice_init(&rpci->pipe, &free_list); + rpci->pipelen = 0; + spin_unlock(&inode->i_lock); + rpc_purge_list(rpci, &free_list, + rpci->ops->destroy_msg, -EAGAIN); + } + } + if (rpci->ops->release_pipe) + rpci->ops->release_pipe(inode); +out: + mutex_unlock(&inode->i_mutex); + return 0; +} + +static ssize_t +rpc_pipe_read(struct file *filp, char __user *buf, size_t len, loff_t *offset) +{ + struct inode *inode = filp->f_path.dentry->d_inode; + struct rpc_inode *rpci = RPC_I(inode); + struct rpc_pipe_msg *msg; + int res = 0; + + mutex_lock(&inode->i_mutex); + if (rpci->ops == NULL) { + res = -EPIPE; + goto out_unlock; + } + msg = filp->private_data; + if (msg == NULL) { + spin_lock(&inode->i_lock); + if (!list_empty(&rpci->pipe)) { + msg = list_entry(rpci->pipe.next, + struct rpc_pipe_msg, + list); + list_move(&msg->list, &rpci->in_upcall); + rpci->pipelen -= msg->len; + filp->private_data = msg; + msg->copied = 0; + } + spin_unlock(&inode->i_lock); + if (msg == NULL) + goto out_unlock; + } + /* NOTE: it is up to the callback to update msg->copied */ + res = rpci->ops->upcall(filp, msg, buf, len); + if (res < 0 || msg->len == msg->copied) { + filp->private_data = NULL; + spin_lock(&inode->i_lock); + list_del(&msg->list); + spin_unlock(&inode->i_lock); + rpci->ops->destroy_msg(msg); + } +out_unlock: + mutex_unlock(&inode->i_mutex); + return res; +} + +static ssize_t +rpc_pipe_write(struct file *filp, const char __user *buf, size_t len, loff_t *offset) +{ + struct inode *inode = filp->f_path.dentry->d_inode; + struct rpc_inode *rpci = RPC_I(inode); + int res; + + mutex_lock(&inode->i_mutex); + res = -EPIPE; + if (rpci->ops != NULL) + res = rpci->ops->downcall(filp, buf, len); + mutex_unlock(&inode->i_mutex); + return res; +} + +static unsigned int +rpc_pipe_poll(struct file *filp, struct poll_table_struct *wait) +{ + struct rpc_inode *rpci; + unsigned int mask = 0; + + rpci = RPC_I(filp->f_path.dentry->d_inode); + poll_wait(filp, &rpci->waitq, wait); + + mask = POLLOUT | POLLWRNORM; + if (rpci->ops == NULL) + mask |= POLLERR | POLLHUP; + if (filp->private_data || !list_empty(&rpci->pipe)) + mask |= POLLIN | POLLRDNORM; + return mask; +} + +static int +rpc_pipe_ioctl(struct inode *ino, struct file *filp, + unsigned int cmd, unsigned long arg) +{ + struct rpc_inode *rpci = RPC_I(filp->f_path.dentry->d_inode); + int len; + + switch (cmd) { + case FIONREAD: + if (rpci->ops == NULL) + return -EPIPE; + len = rpci->pipelen; + if (filp->private_data) { + struct rpc_pipe_msg *msg; + msg = (struct rpc_pipe_msg *)filp->private_data; + len += msg->len - msg->copied; + } + return put_user(len, (int __user *)arg); + default: + return -EINVAL; + } +} + +static const struct file_operations rpc_pipe_fops = { + .owner = THIS_MODULE, + .llseek = no_llseek, + .read = rpc_pipe_read, + .write = rpc_pipe_write, + .poll = rpc_pipe_poll, + .ioctl = rpc_pipe_ioctl, + .open = rpc_pipe_open, + .release = rpc_pipe_release, +}; + +static int +rpc_show_info(struct seq_file *m, void *v) +{ + struct rpc_clnt *clnt = m->private; + + seq_printf(m, "RPC server: %s\n", clnt->cl_server); + seq_printf(m, "service: %s (%d) version %d\n", clnt->cl_protname, + clnt->cl_prog, clnt->cl_vers); + seq_printf(m, "address: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_ADDR)); + seq_printf(m, "protocol: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_PROTO)); + seq_printf(m, "port: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_PORT)); + return 0; +} + +static int +rpc_info_open(struct inode *inode, struct file *file) +{ + struct rpc_clnt *clnt; + int ret = single_open(file, rpc_show_info, NULL); + + if (!ret) { + struct seq_file *m = file->private_data; + mutex_lock(&inode->i_mutex); + clnt = RPC_I(inode)->private; + if (clnt) { + kref_get(&clnt->cl_kref); + m->private = clnt; + } else { + single_release(inode, file); + ret = -EINVAL; + } + mutex_unlock(&inode->i_mutex); + } + return ret; +} + +static int +rpc_info_release(struct inode *inode, struct file *file) +{ + struct seq_file *m = file->private_data; + struct rpc_clnt *clnt = (struct rpc_clnt *)m->private; + + if (clnt) + rpc_release_client(clnt); + return single_release(inode, file); +} + +static const struct file_operations rpc_info_operations = { + .owner = THIS_MODULE, + .open = rpc_info_open, + .read = seq_read, + .llseek = seq_lseek, + .release = rpc_info_release, +}; + + +/* + * We have a single directory with 1 node in it. + */ +enum { + RPCAUTH_Root = 1, + RPCAUTH_lockd, + RPCAUTH_mount, + RPCAUTH_nfs, + RPCAUTH_portmap, + RPCAUTH_statd, + RPCAUTH_RootEOF +}; + +/* + * Description of fs contents. + */ +struct rpc_filelist { + char *name; + const struct file_operations *i_fop; + int mode; +}; + +static struct rpc_filelist files[] = { + [RPCAUTH_lockd] = { + .name = "lockd", + .mode = S_IFDIR | S_IRUGO | S_IXUGO, + }, + [RPCAUTH_mount] = { + .name = "mount", + .mode = S_IFDIR | S_IRUGO | S_IXUGO, + }, + [RPCAUTH_nfs] = { + .name = "nfs", + .mode = S_IFDIR | S_IRUGO | S_IXUGO, + }, + [RPCAUTH_portmap] = { + .name = "portmap", + .mode = S_IFDIR | S_IRUGO | S_IXUGO, + }, + [RPCAUTH_statd] = { + .name = "statd", + .mode = S_IFDIR | S_IRUGO | S_IXUGO, + }, +}; + +enum { + RPCAUTH_info = 2, + RPCAUTH_EOF +}; + +static struct rpc_filelist authfiles[] = { + [RPCAUTH_info] = { + .name = "info", + .i_fop = &rpc_info_operations, + .mode = S_IFREG | S_IRUSR, + }, +}; + +struct vfsmount *rpc_get_mount(void) +{ + int err; + + err = simple_pin_fs(&rpc_pipe_fs_type, &rpc_mount, &rpc_mount_count); + if (err != 0) + return ERR_PTR(err); + return rpc_mount; +} + +void rpc_put_mount(void) +{ + simple_release_fs(&rpc_mount, &rpc_mount_count); +} + +static int rpc_delete_dentry(struct dentry *dentry) +{ + return 1; +} + +static struct dentry_operations rpc_dentry_operations = { + .d_delete = rpc_delete_dentry, +}; + +static int +rpc_lookup_parent(char *path, struct nameidata *nd) +{ + struct vfsmount *mnt; + + if (path[0] == '\0') + return -ENOENT; + + mnt = rpc_get_mount(); + if (IS_ERR(mnt)) { + printk(KERN_WARNING "%s: %s failed to mount " + "pseudofilesystem \n", __FILE__, __func__); + return PTR_ERR(mnt); + } + + if (vfs_path_lookup(mnt->mnt_root, mnt, path, LOOKUP_PARENT, nd)) { + printk(KERN_WARNING "%s: %s failed to find path %s\n", + __FILE__, __func__, path); + rpc_put_mount(); + return -ENOENT; + } + return 0; +} + +static void +rpc_release_path(struct nameidata *nd) +{ + path_put(&nd->path); + rpc_put_mount(); +} + +static struct inode * +rpc_get_inode(struct super_block *sb, int mode) +{ + struct inode *inode = new_inode(sb); + if (!inode) + return NULL; + inode->i_mode = mode; + inode->i_uid = inode->i_gid = 0; + inode->i_blocks = 0; + inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; + switch(mode & S_IFMT) { + case S_IFDIR: + inode->i_fop = &simple_dir_operations; + inode->i_op = &simple_dir_inode_operations; + inc_nlink(inode); + default: + break; + } + return inode; +} + +/* + * FIXME: This probably has races. + */ +static void rpc_depopulate(struct dentry *parent, + unsigned long start, unsigned long eof) +{ + struct inode *dir = parent->d_inode; + struct list_head *pos, *next; + struct dentry *dentry, *dvec[10]; + int n = 0; + + mutex_lock_nested(&dir->i_mutex, I_MUTEX_CHILD); +repeat: + spin_lock(&dcache_lock); + list_for_each_safe(pos, next, &parent->d_subdirs) { + dentry = list_entry(pos, struct dentry, d_u.d_child); + if (!dentry->d_inode || + dentry->d_inode->i_ino < start || + dentry->d_inode->i_ino >= eof) + continue; + spin_lock(&dentry->d_lock); + if (!d_unhashed(dentry)) { + dget_locked(dentry); + __d_drop(dentry); + spin_unlock(&dentry->d_lock); + dvec[n++] = dentry; + if (n == ARRAY_SIZE(dvec)) + break; + } else + spin_unlock(&dentry->d_lock); + } + spin_unlock(&dcache_lock); + if (n) { + do { + dentry = dvec[--n]; + if (S_ISREG(dentry->d_inode->i_mode)) + simple_unlink(dir, dentry); + else if (S_ISDIR(dentry->d_inode->i_mode)) + simple_rmdir(dir, dentry); + d_delete(dentry); + dput(dentry); + } while (n); + goto repeat; + } + mutex_unlock(&dir->i_mutex); +} + +static int +rpc_populate(struct dentry *parent, + struct rpc_filelist *files, + int start, int eof) +{ + struct inode *inode, *dir = parent->d_inode; + void *private = RPC_I(dir)->private; + struct dentry *dentry; + int mode, i; + + mutex_lock(&dir->i_mutex); + for (i = start; i < eof; i++) { + dentry = d_alloc_name(parent, files[i].name); + if (!dentry) + goto out_bad; + dentry->d_op = &rpc_dentry_operations; + mode = files[i].mode; + inode = rpc_get_inode(dir->i_sb, mode); + if (!inode) { + dput(dentry); + goto out_bad; + } + inode->i_ino = i; + if (files[i].i_fop) + inode->i_fop = files[i].i_fop; + if (private) + rpc_inode_setowner(inode, private); + if (S_ISDIR(mode)) + inc_nlink(dir); + d_add(dentry, inode); + fsnotify_create(dir, dentry); + } + mutex_unlock(&dir->i_mutex); + return 0; +out_bad: + mutex_unlock(&dir->i_mutex); + printk(KERN_WARNING "%s: %s failed to populate directory %s\n", + __FILE__, __func__, parent->d_name.name); + return -ENOMEM; +} + +static int +__rpc_mkdir(struct inode *dir, struct dentry *dentry) +{ + struct inode *inode; + + inode = rpc_get_inode(dir->i_sb, S_IFDIR | S_IRUGO | S_IXUGO); + if (!inode) + goto out_err; + inode->i_ino = iunique(dir->i_sb, 100); + d_instantiate(dentry, inode); + inc_nlink(dir); + fsnotify_mkdir(dir, dentry); + return 0; +out_err: + printk(KERN_WARNING "%s: %s failed to allocate inode for dentry %s\n", + __FILE__, __func__, dentry->d_name.name); + return -ENOMEM; +} + +static int +__rpc_rmdir(struct inode *dir, struct dentry *dentry) +{ + int error; + error = simple_rmdir(dir, dentry); + if (!error) + d_delete(dentry); + return error; +} + +static struct dentry * +rpc_lookup_create(struct dentry *parent, const char *name, int len, int exclusive) +{ + struct inode *dir = parent->d_inode; + struct dentry *dentry; + + mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT); + dentry = lookup_one_len(name, parent, len); + if (IS_ERR(dentry)) + goto out_err; + if (!dentry->d_inode) + dentry->d_op = &rpc_dentry_operations; + else if (exclusive) { + dput(dentry); + dentry = ERR_PTR(-EEXIST); + goto out_err; + } + return dentry; +out_err: + mutex_unlock(&dir->i_mutex); + return dentry; +} + +static struct dentry * +rpc_lookup_negative(char *path, struct nameidata *nd) +{ + struct dentry *dentry; + int error; + + if ((error = rpc_lookup_parent(path, nd)) != 0) + return ERR_PTR(error); + dentry = rpc_lookup_create(nd->path.dentry, nd->last.name, nd->last.len, + 1); + if (IS_ERR(dentry)) + rpc_release_path(nd); + return dentry; +} + +/** + * rpc_mkdir - Create a new directory in rpc_pipefs + * @path: path from the rpc_pipefs root to the new directory + * @rpc_client: rpc client to associate with this directory + * + * This creates a directory at the given @path associated with + * @rpc_clnt, which will contain a file named "info" with some basic + * information about the client, together with any "pipes" that may + * later be created using rpc_mkpipe(). + */ +struct dentry * +rpc_mkdir(char *path, struct rpc_clnt *rpc_client) +{ + struct nameidata nd; + struct dentry *dentry; + struct inode *dir; + int error; + + dentry = rpc_lookup_negative(path, &nd); + if (IS_ERR(dentry)) + return dentry; + dir = nd.path.dentry->d_inode; + if ((error = __rpc_mkdir(dir, dentry)) != 0) + goto err_dput; + RPC_I(dentry->d_inode)->private = rpc_client; + error = rpc_populate(dentry, authfiles, + RPCAUTH_info, RPCAUTH_EOF); + if (error) + goto err_depopulate; + dget(dentry); +out: + mutex_unlock(&dir->i_mutex); + rpc_release_path(&nd); + return dentry; +err_depopulate: + rpc_depopulate(dentry, RPCAUTH_info, RPCAUTH_EOF); + __rpc_rmdir(dir, dentry); +err_dput: + dput(dentry); + printk(KERN_WARNING "%s: %s() failed to create directory %s (errno = %d)\n", + __FILE__, __func__, path, error); + dentry = ERR_PTR(error); + goto out; +} + +/** + * rpc_rmdir - Remove a directory created with rpc_mkdir() + * @dentry: directory to remove + */ +int +rpc_rmdir(struct dentry *dentry) +{ + struct dentry *parent; + struct inode *dir; + int error; + + parent = dget_parent(dentry); + dir = parent->d_inode; + mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT); + rpc_depopulate(dentry, RPCAUTH_info, RPCAUTH_EOF); + error = __rpc_rmdir(dir, dentry); + dput(dentry); + mutex_unlock(&dir->i_mutex); + dput(parent); + return error; +} + +/** + * rpc_mkpipe - make an rpc_pipefs file for kernel<->userspace communication + * @parent: dentry of directory to create new "pipe" in + * @name: name of pipe + * @private: private data to associate with the pipe, for the caller's use + * @ops: operations defining the behavior of the pipe: upcall, downcall, + * release_pipe, and destroy_msg. + * @flags: rpc_inode flags + * + * Data is made available for userspace to read by calls to + * rpc_queue_upcall(). The actual reads will result in calls to + * @ops->upcall, which will be called with the file pointer, + * message, and userspace buffer to copy to. + * + * Writes can come at any time, and do not necessarily have to be + * responses to upcalls. They will result in calls to @msg->downcall. + * + * The @private argument passed here will be available to all these methods + * from the file pointer, via RPC_I(file->f_dentry->d_inode)->private. + */ +struct dentry * +rpc_mkpipe(struct dentry *parent, const char *name, void *private, struct rpc_pipe_ops *ops, int flags) +{ + struct dentry *dentry; + struct inode *dir, *inode; + struct rpc_inode *rpci; + + dentry = rpc_lookup_create(parent, name, strlen(name), 0); + if (IS_ERR(dentry)) + return dentry; + dir = parent->d_inode; + if (dentry->d_inode) { + rpci = RPC_I(dentry->d_inode); + if (rpci->private != private || + rpci->ops != ops || + rpci->flags != flags) { + dput (dentry); + dentry = ERR_PTR(-EBUSY); + } + rpci->nkern_readwriters++; + goto out; + } + inode = rpc_get_inode(dir->i_sb, S_IFIFO | S_IRUSR | S_IWUSR); + if (!inode) + goto err_dput; + inode->i_ino = iunique(dir->i_sb, 100); + inode->i_fop = &rpc_pipe_fops; + d_instantiate(dentry, inode); + rpci = RPC_I(inode); + rpci->private = private; + rpci->flags = flags; + rpci->ops = ops; + rpci->nkern_readwriters = 1; + fsnotify_create(dir, dentry); + dget(dentry); +out: + mutex_unlock(&dir->i_mutex); + return dentry; +err_dput: + dput(dentry); + dentry = ERR_PTR(-ENOMEM); + printk(KERN_WARNING "%s: %s() failed to create pipe %s/%s (errno = %d)\n", + __FILE__, __func__, parent->d_name.name, name, + -ENOMEM); + goto out; +} +EXPORT_SYMBOL(rpc_mkpipe); + +/** + * rpc_unlink - remove a pipe + * @dentry: dentry for the pipe, as returned from rpc_mkpipe + * + * After this call, lookups will no longer find the pipe, and any + * attempts to read or write using preexisting opens of the pipe will + * return -EPIPE. + */ +int +rpc_unlink(struct dentry *dentry) +{ + struct dentry *parent; + struct inode *dir; + int error = 0; + + parent = dget_parent(dentry); + dir = parent->d_inode; + mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT); + if (--RPC_I(dentry->d_inode)->nkern_readwriters == 0) { + rpc_close_pipes(dentry->d_inode); + error = simple_unlink(dir, dentry); + if (!error) + d_delete(dentry); + } + dput(dentry); + mutex_unlock(&dir->i_mutex); + dput(parent); + return error; +} +EXPORT_SYMBOL(rpc_unlink); + +/* + * populate the filesystem + */ +static struct super_operations s_ops = { + .alloc_inode = rpc_alloc_inode, + .destroy_inode = rpc_destroy_inode, + .statfs = simple_statfs, +}; + +#define RPCAUTH_GSSMAGIC 0x67596969 + +static int +rpc_fill_super(struct super_block *sb, void *data, int silent) +{ + struct inode *inode; + struct dentry *root; + + sb->s_blocksize = PAGE_CACHE_SIZE; + sb->s_blocksize_bits = PAGE_CACHE_SHIFT; + sb->s_magic = RPCAUTH_GSSMAGIC; + sb->s_op = &s_ops; + sb->s_time_gran = 1; + + inode = rpc_get_inode(sb, S_IFDIR | 0755); + if (!inode) + return -ENOMEM; + root = d_alloc_root(inode); + if (!root) { + iput(inode); + return -ENOMEM; + } + if (rpc_populate(root, files, RPCAUTH_Root + 1, RPCAUTH_RootEOF)) + goto out; + sb->s_root = root; + return 0; +out: + d_genocide(root); + dput(root); + return -ENOMEM; +} + +static int +rpc_get_sb(struct file_system_type *fs_type, + int flags, const char *dev_name, void *data, struct vfsmount *mnt) +{ + return get_sb_single(fs_type, flags, data, rpc_fill_super, mnt); +} + +static struct file_system_type rpc_pipe_fs_type = { + .owner = THIS_MODULE, + .name = "rpc_pipefs", + .get_sb = rpc_get_sb, + .kill_sb = kill_litter_super, +}; + +static void +init_once(void *foo) +{ + struct rpc_inode *rpci = (struct rpc_inode *) foo; + + inode_init_once(&rpci->vfs_inode); + rpci->private = NULL; + rpci->nreaders = 0; + rpci->nwriters = 0; + INIT_LIST_HEAD(&rpci->in_upcall); + INIT_LIST_HEAD(&rpci->in_downcall); + INIT_LIST_HEAD(&rpci->pipe); + rpci->pipelen = 0; + init_waitqueue_head(&rpci->waitq); + INIT_DELAYED_WORK(&rpci->queue_timeout, + rpc_timeout_upcall_queue); + rpci->ops = NULL; +} + +int register_rpc_pipefs(void) +{ + int err; + + rpc_inode_cachep = kmem_cache_create("rpc_inode_cache", + sizeof(struct rpc_inode), + 0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT| + SLAB_MEM_SPREAD), + init_once); + if (!rpc_inode_cachep) + return -ENOMEM; + err = register_filesystem(&rpc_pipe_fs_type); + if (err) { + kmem_cache_destroy(rpc_inode_cachep); + return err; + } + + return 0; +} + +void unregister_rpc_pipefs(void) +{ + kmem_cache_destroy(rpc_inode_cachep); + unregister_filesystem(&rpc_pipe_fs_type); +} |