/* FUSE: Filesystem in Userspace Copyright (C) 2001-2006 Miklos Szeredi <miklos@szeredi.hu> This program can be distributed under the terms of the GNU GPL. See the file COPYING. */ #include "fuse_i.h" #include <linux/pagemap.h> #include <linux/slab.h> #include <linux/file.h> #include <linux/seq_file.h> #include <linux/init.h> #include <linux/module.h> #include <linux/parser.h> #include <linux/statfs.h> #include <linux/random.h> #include <linux/sched.h> MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>"); MODULE_DESCRIPTION("Filesystem in Userspace"); MODULE_LICENSE("GPL"); static struct kmem_cache *fuse_inode_cachep; struct list_head fuse_conn_list; DEFINE_MUTEX(fuse_mutex); #define FUSE_SUPER_MAGIC 0x65735546 struct fuse_mount_data { int fd; unsigned rootmode; unsigned user_id; unsigned group_id; unsigned fd_present : 1; unsigned rootmode_present : 1; unsigned user_id_present : 1; unsigned group_id_present : 1; unsigned flags; unsigned max_read; unsigned blksize; }; static struct inode *fuse_alloc_inode(struct super_block *sb) { struct inode *inode; struct fuse_inode *fi; inode = kmem_cache_alloc(fuse_inode_cachep, GFP_KERNEL); if (!inode) return NULL; fi = get_fuse_inode(inode); fi->i_time = 0; fi->nodeid = 0; fi->nlookup = 0; fi->forget_req = fuse_request_alloc(); if (!fi->forget_req) { kmem_cache_free(fuse_inode_cachep, inode); return NULL; } return inode; } static void fuse_destroy_inode(struct inode *inode) { struct fuse_inode *fi = get_fuse_inode(inode); if (fi->forget_req) fuse_request_free(fi->forget_req); kmem_cache_free(fuse_inode_cachep, inode); } static void fuse_read_inode(struct inode *inode) { /* No op */ } void fuse_send_forget(struct fuse_conn *fc, struct fuse_req *req, unsigned long nodeid, u64 nlookup) { struct fuse_forget_in *inarg = &req->misc.forget_in; inarg->nlookup = nlookup; req->in.h.opcode = FUSE_FORGET; req->in.h.nodeid = nodeid; req->in.numargs = 1; req->in.args[0].size = sizeof(struct fuse_forget_in); req->in.args[0].value = inarg; request_send_noreply(fc, req); } static void fuse_clear_inode(struct inode *inode) { if (inode->i_sb->s_flags & MS_ACTIVE) { struct fuse_conn *fc = get_fuse_conn(inode); struct fuse_inode *fi = get_fuse_inode(inode); fuse_send_forget(fc, fi->forget_req, fi->nodeid, fi->nlookup); fi->forget_req = NULL; } } static int fuse_remount_fs(struct super_block *sb, int *flags, char *data) { if (*flags & MS_MANDLOCK) return -EINVAL; return 0; } void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr) { struct fuse_conn *fc = get_fuse_conn(inode); if (S_ISREG(inode->i_mode) && i_size_read(inode) != attr->size) invalidate_mapping_pages(inode->i_mapping, 0, -1); inode->i_ino = attr->ino; inode->i_mode = (inode->i_mode & S_IFMT) + (attr->mode & 07777); inode->i_nlink = attr->nlink; inode->i_uid = attr->uid; inode->i_gid = attr->gid; spin_lock(&fc->lock); i_size_write(inode, attr->size); spin_unlock(&fc->lock); inode->i_blocks = attr->blocks; inode->i_atime.tv_sec = attr->atime; inode->i_atime.tv_nsec = attr->atimensec; inode->i_mtime.tv_sec = attr->mtime; inode->i_mtime.tv_nsec = attr->mtimensec; inode->i_ctime.tv_sec = attr->ctime; inode->i_ctime.tv_nsec = attr->ctimensec; } static void fuse_init_inode(struct inode *inode, struct fuse_attr *attr) { inode->i_mode = attr->mode & S_IFMT; inode->i_size = attr->size; if (S_ISREG(inode->i_mode)) { fuse_init_common(inode); fuse_init_file_inode(inode); } else if (S_ISDIR(inode->i_mode)) fuse_init_dir(inode); else if (S_ISLNK(inode->i_mode)) fuse_init_symlink(inode); else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) || S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) { fuse_init_common(inode); init_special_inode(inode, inode->i_mode, new_decode_dev(attr->rdev)); } else BUG(); } static int fuse_inode_eq(struct inode *inode, void *_nodeidp) { unsigned long nodeid = *(unsigned long *) _nodeidp; if (get_node_id(inode) == nodeid) return 1; else return 0; } static int fuse_inode_set(struct inode *inode, void *_nodeidp) { unsigned long nodeid = *(unsigned long *) _nodeidp; get_fuse_inode(inode)->nodeid = nodeid; return 0; } struct inode *fuse_iget(struct super_block *sb, unsigned long nodeid, int generation, struct fuse_attr *attr) { struct inode *inode; struct fuse_inode *fi; struct fuse_conn *fc = get_fuse_conn_super(sb); retry: inode = iget5_locked(sb, nodeid, fuse_inode_eq, fuse_inode_set, &nodeid); if (!inode) return NULL; if ((inode->i_state & I_NEW)) { inode->i_flags |= S_NOATIME|S_NOCMTIME; inode->i_generation = generation; inode->i_data.backing_dev_info = &fc->bdi; fuse_init_inode(inode, attr); unlock_new_inode(inode); } else if ((inode->i_mode ^ attr->mode) & S_IFMT) { /* Inode has changed type, any I/O on the old should fail */ make_bad_inode(inode); iput(inode); goto retry; } fi = get_fuse_inode(inode); spin_lock(&fc->lock); fi->nlookup ++; spin_unlock(&fc->lock); fuse_change_attributes(inode, attr); return inode; } static void fuse_umount_begin(struct vfsmount *vfsmnt, int flags) { if (flags & MNT_FORCE) fuse_abort_conn(get_fuse_conn_super(vfsmnt->mnt_sb)); } static void fuse_send_destroy(struct fuse_conn *fc) { struct fuse_req *req = fc->destroy_req; if (req && fc->conn_init) { fc->destroy_req = NULL; req->in.h.opcode = FUSE_DESTROY; req->force = 1; request_send(fc, req); fuse_put_request(fc, req); } } static void fuse_put_super(struct super_block *sb) { struct fuse_conn *fc = get_fuse_conn_super(sb); fuse_send_destroy(fc); spin_lock(&fc->lock); fc->connected = 0; fc->blocked = 0; spin_unlock(&fc->lock); /* Flush all readers on this fs */ kill_fasync(&fc->fasync, SIGIO, POLL_IN); wake_up_all(&fc->waitq); wake_up_all(&fc->blocked_waitq); mutex_lock(&fuse_mutex); list_del(&fc->entry); fuse_ctl_remove_conn(fc); mutex_unlock(&fuse_mutex); fuse_conn_put(fc); } static void convert_fuse_statfs(struct kstatfs *stbuf, struct fuse_kstatfs *attr) { stbuf->f_type = FUSE_SUPER_MAGIC; stbuf->f_bsize = attr->bsize; stbuf->f_frsize = attr->frsize; stbuf->f_blocks = attr->blocks; stbuf->f_bfree = attr->bfree; stbuf->f_bavail = attr->bavail; stbuf->f_files = attr->files; stbuf->f_ffree = attr->ffree; stbuf->f_namelen = attr->namelen; /* fsid is left zero */ } static int fuse_statfs(struct dentry *dentry, struct kstatfs *buf) { struct super_block *sb = dentry->d_sb; struct fuse_conn *fc = get_fuse_conn_super(sb); struct fuse_req *req; struct fuse_statfs_out outarg; int err; req = fuse_get_req(fc); if (IS_ERR(req)) return PTR_ERR(req); memset(&outarg, 0, sizeof(outarg)); req->in.numargs = 0; req->in.h.opcode = FUSE_STATFS; req->in.h.nodeid = get_node_id(dentry->d_inode); req->out.numargs = 1; req->out.args[0].size = fc->minor < 4 ? FUSE_COMPAT_STATFS_SIZE : sizeof(outarg); req->out.args[0].value = &outarg; request_send(fc, req); err = req->out.h.error; if (!err) convert_fuse_statfs(buf, &outarg.st); fuse_put_request(fc, req); return err; } enum { OPT_FD, OPT_ROOTMODE, OPT_USER_ID, OPT_GROUP_ID, OPT_DEFAULT_PERMISSIONS, OPT_ALLOW_OTHER, OPT_MAX_READ, OPT_BLKSIZE, OPT_ERR }; static match_table_t tokens = { {OPT_FD, "fd=%u"}, {OPT_ROOTMODE, "rootmode=%o"}, {OPT_USER_ID, "user_id=%u"}, {OPT_GROUP_ID, "group_id=%u"}, {OPT_DEFAULT_PERMISSIONS, "default_permissions"}, {OPT_ALLOW_OTHER, "allow_other"}, {OPT_MAX_READ, "max_read=%u"}, {OPT_BLKSIZE, "blksize=%u"}, {OPT_ERR, NULL} }; static int parse_fuse_opt(char *opt, struct fuse_mount_data *d, int is_bdev) { char *p; memset(d, 0, sizeof(struct fuse_mount_data)); d->max_read = ~0; d->blksize = 512; while ((p = strsep(&opt, ",")) != NULL) { int token; int value; substring_t args[MAX_OPT_ARGS]; if (!*p) continue; token = match_token(p, tokens, args); switch (token) { case OPT_FD: if (match_int(&args[0], &value)) return 0; d->fd = value; d->fd_present = 1; break; case OPT_ROOTMODE: if (match_octal(&args[0], &value)) return 0; if (!fuse_valid_type(value)) return 0; d->rootmode = value; d->rootmode_present = 1; break; case OPT_USER_ID: if (match_int(&args[0], &value)) return 0; d->user_id = value; d->user_id_present = 1; break; case OPT_GROUP_ID: if (match_int(&args[0], &value)) return 0; d->group_id = value; d->group_id_present = 1; break; case OPT_DEFAULT_PERMISSIONS: d->flags |= FUSE_DEFAULT_PERMISSIONS; break; case OPT_ALLOW_OTHER: d->flags |= FUSE_ALLOW_OTHER; break; case OPT_MAX_READ: if (match_int(&args[0], &value)) return 0; d->max_read = value; break; case OPT_BLKSIZE: if (!is_bdev || match_int(&args[0], &value)) return 0; d->blksize = value; break; default: return 0; } } if (!d->fd_present || !d->rootmode_present || !d->user_id_present || !d->group_id_present) return 0; return 1; } static int fuse_show_options(struct seq_file *m, struct vfsmount *mnt) { struct fuse_conn *fc = get_fuse_conn_super(mnt->mnt_sb); seq_printf(m, ",user_id=%u", fc->user_id); seq_printf(m, ",group_id=%u", fc->group_id); if (fc->flags & FUSE_DEFAULT_PERMISSIONS) seq_puts(m, ",default_permissions"); if (fc->flags & FUSE_ALLOW_OTHER) seq_puts(m, ",allow_other"); if (fc->max_read != ~0) seq_printf(m, ",max_read=%u", fc->max_read); return 0; } static struct fuse_conn *new_conn(void) { struct fuse_conn *fc; fc = kzalloc(sizeof(*fc), GFP_KERNEL); if (fc) { spin_lock_init(&fc->lock); mutex_init(&fc->inst_mutex); atomic_set(&fc->count, 1); init_waitqueue_head(&fc->waitq); init_waitqueue_head(&fc->blocked_waitq); INIT_LIST_HEAD(&fc->pending); INIT_LIST_HEAD(&fc->processing); INIT_LIST_HEAD(&fc->io); INIT_LIST_HEAD(&fc->interrupts); atomic_set(&fc->num_waiting, 0); fc->bdi.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE; fc->bdi.unplug_io_fn = default_unplug_io_fn; fc->reqctr = 0; fc->blocked = 1; get_random_bytes(&fc->scramble_key, sizeof(fc->scramble_key)); } return fc; } void fuse_conn_put(struct fuse_conn *fc) { if (atomic_dec_and_test(&fc->count)) { if (fc->destroy_req) fuse_request_free(fc->destroy_req); mutex_destroy(&fc->inst_mutex); kfree(fc); } } struct fuse_conn *fuse_conn_get(struct fuse_conn *fc) { atomic_inc(&fc->count); return fc; } static struct inode *get_root_inode(struct super_block *sb, unsigned mode) { struct fuse_attr attr; memset(&attr, 0, sizeof(attr)); attr.mode = mode; attr.ino = FUSE_ROOT_ID; return fuse_iget(sb, 1, 0, &attr); } static const struct super_operations fuse_super_operations = { .alloc_inode = fuse_alloc_inode, .destroy_inode = fuse_destroy_inode, .read_inode = fuse_read_inode, .clear_inode = fuse_clear_inode, .drop_inode = generic_delete_inode, .remount_fs = fuse_remount_fs, .put_super = fuse_put_super, .umount_begin = fuse_umount_begin, .statfs = fuse_statfs, .show_options = fuse_show_options, }; static void process_init_reply(struct fuse_conn *fc, struct fuse_req *req) { struct fuse_init_out *arg = &req->misc.init_out; if (req->out.h.error || arg->major != FUSE_KERNEL_VERSION) fc->conn_error = 1; else { unsigned long ra_pages; if (arg->minor >= 6) { ra_pages = arg->max_readahead / PAGE_CACHE_SIZE; if (arg->flags & FUSE_ASYNC_READ) fc->async_read = 1; if (!(arg->flags & FUSE_POSIX_LOCKS)) fc->no_lock = 1; } else { ra_pages = fc->max_read / PAGE_CACHE_SIZE; fc->no_lock = 1; } fc->bdi.ra_pages = min(fc->bdi.ra_pages, ra_pages); fc->minor = arg->minor; fc->max_write = arg->minor < 5 ? 4096 : arg->max_write; fc->conn_init = 1; } fuse_put_request(fc, req); fc->blocked = 0; wake_up_all(&fc->blocked_waitq); } static void fuse_send_init(struct fuse_conn *fc, struct fuse_req *req) { struct fuse_init_in *arg = &req->misc.init_in; arg->major = FUSE_KERNEL_VERSION; arg->minor = FUSE_KERNEL_MINOR_VERSION; arg->max_readahead = fc->bdi.ra_pages * PAGE_CACHE_SIZE; arg->flags |= FUSE_ASYNC_READ | FUSE_POSIX_LOCKS; req->in.h.opcode = FUSE_INIT; req->in.numargs = 1; req->in.args[0].size = sizeof(*arg); req->in.args[0].value = arg; req->out.numargs = 1; /* Variable length arguement used for backward compatibility with interface version < 7.5. Rest of init_out is zeroed by do_get_request(), so a short reply is not a problem */ req->out.argvar = 1; req->out.args[0].size = sizeof(struct fuse_init_out); req->out.args[0].value = &req->misc.init_out; req->end = process_init_reply; request_send_background(fc, req); } static u64 conn_id(void) { static u64 ctr = 1; return ctr++; } static int fuse_fill_super(struct super_block *sb, void *data, int silent) { struct fuse_conn *fc; struct inode *root; struct fuse_mount_data d; struct file *file; struct dentry *root_dentry; struct fuse_req *init_req; int err; int is_bdev = sb->s_bdev != NULL; if (sb->s_flags & MS_MANDLOCK) return -EINVAL; if (!parse_fuse_opt((char *) data, &d, is_bdev)) return -EINVAL; if (is_bdev) { #ifdef CONFIG_BLOCK if (!sb_set_blocksize(sb, d.blksize)) return -EINVAL; #endif } else { sb->s_blocksize = PAGE_CACHE_SIZE; sb->s_blocksize_bits = PAGE_CACHE_SHIFT; } sb->s_magic = FUSE_SUPER_MAGIC; sb->s_op = &fuse_super_operations; sb->s_maxbytes = MAX_LFS_FILESIZE; file = fget(d.fd); if (!file) return -EINVAL; if (file->f_op != &fuse_dev_operations) return -EINVAL; fc = new_conn(); if (!fc) return -ENOMEM; fc->flags = d.flags; fc->user_id = d.user_id; fc->group_id = d.group_id; fc->max_read = d.max_read; /* Used by get_root_inode() */ sb->s_fs_info = fc; err = -ENOMEM; root = get_root_inode(sb, d.rootmode); if (!root) goto err; root_dentry = d_alloc_root(root); if (!root_dentry) { iput(root); goto err; } init_req = fuse_request_alloc(); if (!init_req) goto err_put_root; if (is_bdev) { fc->destroy_req = fuse_request_alloc(); if (!fc->destroy_req) goto err_put_root; } mutex_lock(&fuse_mutex); err = -EINVAL; if (file->private_data) goto err_unlock; fc->id = conn_id(); err = fuse_ctl_add_conn(fc); if (err) goto err_unlock; list_add_tail(&fc->entry, &fuse_conn_list); sb->s_root = root_dentry; fc->connected = 1; file->private_data = fuse_conn_get(fc); mutex_unlock(&fuse_mutex); /* * atomic_dec_and_test() in fput() provides the necessary * memory barrier for file->private_data to be visible on all * CPUs after this */ fput(file); fuse_send_init(fc, init_req); return 0; err_unlock: mutex_unlock(&fuse_mutex); fuse_request_free(init_req); err_put_root: dput(root_dentry); err: fput(file); fuse_conn_put(fc); return err; } static int fuse_get_sb(struct file_system_type *fs_type, int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt) { return get_sb_nodev(fs_type, flags, raw_data, fuse_fill_super, mnt); } static struct file_system_type fuse_fs_type = { .owner = THIS_MODULE, .name = "fuse", .fs_flags = FS_HAS_SUBTYPE, .get_sb = fuse_get_sb, .kill_sb = kill_anon_super, }; #ifdef CONFIG_BLOCK static int fuse_get_sb_blk(struct file_system_type *fs_type, int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt) { return get_sb_bdev(fs_type, flags, dev_name, raw_data, fuse_fill_super, mnt); } static struct file_system_type fuseblk_fs_type = { .owner = THIS_MODULE, .name = "fuseblk", .get_sb = fuse_get_sb_blk, .kill_sb = kill_block_super, .fs_flags = FS_REQUIRES_DEV | FS_HAS_SUBTYPE, }; static inline int register_fuseblk(void) { return register_filesystem(&fuseblk_fs_type); } static inline void unregister_fuseblk(void) { unregister_filesystem(&fuseblk_fs_type); } #else static inline int register_fuseblk(void) { return 0; } static inline void unregister_fuseblk(void) { } #endif static decl_subsys(fuse, NULL, NULL); static decl_subsys(connections, NULL, NULL); static void fuse_inode_init_once(void *foo, struct kmem_cache *cachep, unsigned long flags) { struct inode * inode = foo; inode_init_once(inode); } static int __init fuse_fs_init(void) { int err; err = register_filesystem(&fuse_fs_type); if (err) goto out; err = register_fuseblk(); if (err) goto out_unreg; fuse_inode_cachep = kmem_cache_create("fuse_inode", sizeof(struct fuse_inode), 0, SLAB_HWCACHE_ALIGN, fuse_inode_init_once, NULL); err = -ENOMEM; if (!fuse_inode_cachep) goto out_unreg2; return 0; out_unreg2: unregister_fuseblk(); out_unreg: unregister_filesystem(&fuse_fs_type); out: return err; } static void fuse_fs_cleanup(void) { unregister_filesystem(&fuse_fs_type); unregister_fuseblk(); kmem_cache_destroy(fuse_inode_cachep); } static int fuse_sysfs_init(void) { int err; kobj_set_kset_s(&fuse_subsys, fs_subsys); err = subsystem_register(&fuse_subsys); if (err) goto out_err; kobj_set_kset_s(&connections_subsys, fuse_subsys); err = subsystem_register(&connections_subsys); if (err) goto out_fuse_unregister; return 0; out_fuse_unregister: subsystem_unregister(&fuse_subsys); out_err: return err; } static void fuse_sysfs_cleanup(void) { subsystem_unregister(&connections_subsys); subsystem_unregister(&fuse_subsys); } static int __init fuse_init(void) { int res; printk("fuse init (API version %i.%i)\n", FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION); INIT_LIST_HEAD(&fuse_conn_list); res = fuse_fs_init(); if (res) goto err; res = fuse_dev_init(); if (res) goto err_fs_cleanup; res = fuse_sysfs_init(); if (res) goto err_dev_cleanup; res = fuse_ctl_init(); if (res) goto err_sysfs_cleanup; return 0; err_sysfs_cleanup: fuse_sysfs_cleanup(); err_dev_cleanup: fuse_dev_cleanup(); err_fs_cleanup: fuse_fs_cleanup(); err: return res; } static void __exit fuse_exit(void) { printk(KERN_DEBUG "fuse exit\n"); fuse_ctl_cleanup(); fuse_sysfs_cleanup(); fuse_fs_cleanup(); fuse_dev_cleanup(); } module_init(fuse_init); module_exit(fuse_exit);