/* FUSE: Filesystem in Userspace Copyright (C) 2001-2005 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/mount.h> #include <linux/seq_file.h> #include <linux/init.h> #include <linux/module.h> #include <linux/parser.h> #include <linux/statfs.h> MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>"); MODULE_DESCRIPTION("Filesystem in Userspace"); MODULE_LICENSE("GPL"); spinlock_t fuse_lock; static kmem_cache_t *fuse_inode_cachep; #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; }; static struct inode *fuse_alloc_inode(struct super_block *sb) { struct inode *inode; struct fuse_inode *fi; inode = kmem_cache_alloc(fuse_inode_cachep, SLAB_KERNEL); if (!inode) return NULL; fi = get_fuse_inode(inode); fi->i_time = jiffies - 1; 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; } } void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr) { if (S_ISREG(inode->i_mode) && i_size_read(inode) != attr->size) invalidate_inode_pages(inode->i_mapping); 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; i_size_write(inode, attr->size); inode->i_blksize = PAGE_CACHE_SIZE; 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; i_size_write(inode, 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 { /* Don't let user create weird files */ inode->i_mode = S_IFREG; fuse_init_common(inode); fuse_init_file_inode(inode); } } 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); int retried = 0; 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) { BUG_ON(retried); /* Inode has changed type, any I/O on the old should fail */ make_bad_inode(inode); iput(inode); retried = 1; goto retry; } fi = get_fuse_inode(inode); fi->nlookup ++; fuse_change_attributes(inode, attr); return inode; } static void fuse_put_super(struct super_block *sb) { struct fuse_conn *fc = get_fuse_conn_super(sb); down_write(&fc->sbput_sem); while (!list_empty(&fc->background)) fuse_release_background(list_entry(fc->background.next, struct fuse_req, bg_entry)); spin_lock(&fuse_lock); fc->mounted = 0; fc->user_id = 0; fc->group_id = 0; fc->flags = 0; /* Flush all readers on this fs */ wake_up_all(&fc->waitq); up_write(&fc->sbput_sem); fuse_release_conn(fc); spin_unlock(&fuse_lock); } 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_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 super_block *sb, struct kstatfs *buf) { struct fuse_conn *fc = get_fuse_conn_super(sb); struct fuse_req *req; struct fuse_statfs_out outarg; int err; req = fuse_get_request(fc); if (!req) return -EINTR; req->in.numargs = 0; req->in.h.opcode = FUSE_STATFS; req->out.numargs = 1; req->out.args[0].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_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_ERR, NULL} }; static int parse_fuse_opt(char *opt, struct fuse_mount_data *d) { char *p; memset(d, 0, sizeof(struct fuse_mount_data)); d->max_read = ~0; 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; 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; 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 void free_conn(struct fuse_conn *fc) { while (!list_empty(&fc->unused_list)) { struct fuse_req *req; req = list_entry(fc->unused_list.next, struct fuse_req, list); list_del(&req->list); fuse_request_free(req); } kfree(fc); } /* Must be called with the fuse lock held */ void fuse_release_conn(struct fuse_conn *fc) { fc->count--; if (!fc->count) free_conn(fc); } static struct fuse_conn *new_conn(void) { struct fuse_conn *fc; fc = kmalloc(sizeof(*fc), GFP_KERNEL); if (fc != NULL) { int i; memset(fc, 0, sizeof(*fc)); init_waitqueue_head(&fc->waitq); INIT_LIST_HEAD(&fc->pending); INIT_LIST_HEAD(&fc->processing); INIT_LIST_HEAD(&fc->unused_list); INIT_LIST_HEAD(&fc->background); sema_init(&fc->outstanding_sem, 0); init_rwsem(&fc->sbput_sem); for (i = 0; i < FUSE_MAX_OUTSTANDING; i++) { struct fuse_req *req = fuse_request_alloc(); if (!req) { free_conn(fc); return NULL; } list_add(&req->list, &fc->unused_list); } fc->bdi.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE; fc->bdi.unplug_io_fn = default_unplug_io_fn; fc->reqctr = 0; } return fc; } static struct fuse_conn *get_conn(struct file *file, struct super_block *sb) { struct fuse_conn *fc; if (file->f_op != &fuse_dev_operations) return ERR_PTR(-EINVAL); fc = new_conn(); if (fc == NULL) return ERR_PTR(-ENOMEM); spin_lock(&fuse_lock); if (file->private_data) { free_conn(fc); fc = ERR_PTR(-EINVAL); } else { file->private_data = fc; *get_fuse_conn_super_p(sb) = fc; fc->mounted = 1; fc->connected = 1; fc->count = 2; } spin_unlock(&fuse_lock); 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 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, .put_super = fuse_put_super, .statfs = fuse_statfs, .show_options = fuse_show_options, }; 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; int err; if (!parse_fuse_opt((char *) data, &d)) return -EINVAL; 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; fc = get_conn(file, sb); fput(file); if (IS_ERR(fc)) return PTR_ERR(fc); fc->flags = d.flags; fc->user_id = d.user_id; fc->group_id = d.group_id; fc->max_read = d.max_read; if (fc->max_read / PAGE_CACHE_SIZE < fc->bdi.ra_pages) fc->bdi.ra_pages = fc->max_read / PAGE_CACHE_SIZE; fc->max_write = FUSE_MAX_IN / 2; err = -ENOMEM; root = get_root_inode(sb, d.rootmode); if (root == NULL) goto err; sb->s_root = d_alloc_root(root); if (!sb->s_root) { iput(root); goto err; } fuse_send_init(fc); return 0; err: spin_lock(&fuse_lock); fuse_release_conn(fc); spin_unlock(&fuse_lock); return err; } static struct super_block *fuse_get_sb(struct file_system_type *fs_type, int flags, const char *dev_name, void *raw_data) { return get_sb_nodev(fs_type, flags, raw_data, fuse_fill_super); } static struct file_system_type fuse_fs_type = { .owner = THIS_MODULE, .name = "fuse", .get_sb = fuse_get_sb, .kill_sb = kill_anon_super, }; static void fuse_inode_init_once(void *foo, kmem_cache_t *cachep, unsigned long flags) { struct inode * inode = foo; if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) == SLAB_CTOR_CONSTRUCTOR) inode_init_once(inode); } static int __init fuse_fs_init(void) { int err; err = register_filesystem(&fuse_fs_type); if (err) printk("fuse: failed to register filesystem\n"); else { fuse_inode_cachep = kmem_cache_create("fuse_inode", sizeof(struct fuse_inode), 0, SLAB_HWCACHE_ALIGN, fuse_inode_init_once, NULL); if (!fuse_inode_cachep) { unregister_filesystem(&fuse_fs_type); err = -ENOMEM; } } return err; } static void fuse_fs_cleanup(void) { unregister_filesystem(&fuse_fs_type); kmem_cache_destroy(fuse_inode_cachep); } static int __init fuse_init(void) { int res; printk("fuse init (API version %i.%i)\n", FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION); spin_lock_init(&fuse_lock); res = fuse_fs_init(); if (res) goto err; res = fuse_dev_init(); if (res) goto err_fs_cleanup; return 0; err_fs_cleanup: fuse_fs_cleanup(); err: return res; } static void __exit fuse_exit(void) { printk(KERN_DEBUG "fuse exit\n"); fuse_fs_cleanup(); fuse_dev_cleanup(); } module_init(fuse_init); module_exit(fuse_exit);