From bafa96541b250a7051e3fbc5de6e8369daf8ffec Mon Sep 17 00:00:00 2001 From: Miklos Szeredi Date: Sun, 25 Jun 2006 05:48:51 -0700 Subject: [PATCH] fuse: add control filesystem Add a control filesystem to fuse, replacing the attributes currently exported through sysfs. An empty directory '/sys/fs/fuse/connections' is still created in sysfs, and mounting the control filesystem here provides backward compatibility. Advantages of the control filesystem over the previous solution: - allows the object directory and the attributes to be owned by the filesystem owner, hence letting unpriviled users abort the filesystem connection - does not suffer from module unload race [akpm@osdl.org: fix this fs for recent dhowells depredations] [akpm@osdl.org: fix 64-bit printk warnings] Signed-off-by: Miklos Szeredi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/fuse/inode.c | 141 ++++++++++++++++++-------------------------------------- 1 file changed, 44 insertions(+), 97 deletions(-) (limited to 'fs/fuse/inode.c') diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c index 0225729977c..13a7e8ab7a7 100644 --- a/fs/fuse/inode.c +++ b/fs/fuse/inode.c @@ -22,13 +22,8 @@ MODULE_DESCRIPTION("Filesystem in Userspace"); MODULE_LICENSE("GPL"); static kmem_cache_t *fuse_inode_cachep; -static struct subsystem connections_subsys; - -struct fuse_conn_attr { - struct attribute attr; - ssize_t (*show)(struct fuse_conn *, char *); - ssize_t (*store)(struct fuse_conn *, const char *, size_t); -}; +struct list_head fuse_conn_list; +DEFINE_MUTEX(fuse_mutex); #define FUSE_SUPER_MAGIC 0x65735546 @@ -211,8 +206,11 @@ static void fuse_put_super(struct super_block *sb) kill_fasync(&fc->fasync, SIGIO, POLL_IN); wake_up_all(&fc->waitq); wake_up_all(&fc->blocked_waitq); - kobject_del(&fc->kobj); - kobject_put(&fc->kobj); + 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) @@ -362,11 +360,6 @@ static int fuse_show_options(struct seq_file *m, struct vfsmount *mnt) return 0; } -static void fuse_conn_release(struct kobject *kobj) -{ - kfree(get_fuse_conn_kobj(kobj)); -} - static struct fuse_conn *new_conn(void) { struct fuse_conn *fc; @@ -374,13 +367,12 @@ static struct fuse_conn *new_conn(void) fc = kzalloc(sizeof(*fc), GFP_KERNEL); if (fc) { spin_lock_init(&fc->lock); + 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); - kobj_set_kset_s(fc, connections_subsys); - kobject_init(&fc->kobj); 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; @@ -390,6 +382,18 @@ static struct fuse_conn *new_conn(void) return fc; } +void fuse_conn_put(struct fuse_conn *fc) +{ + if (atomic_dec_and_test(&fc->count)) + 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; @@ -459,10 +463,9 @@ static void fuse_send_init(struct fuse_conn *fc, struct fuse_req *req) request_send_background(fc, req); } -static unsigned long long conn_id(void) +static u64 conn_id(void) { - /* BKL is held for ->get_sb() */ - static unsigned long long ctr = 1; + static u64 ctr = 1; return ctr++; } @@ -519,24 +522,21 @@ static int fuse_fill_super(struct super_block *sb, void *data, int silent) if (!init_req) goto err_put_root; - err = kobject_set_name(&fc->kobj, "%llu", conn_id()); - if (err) - goto err_free_req; - - err = kobject_add(&fc->kobj); - if (err) - goto err_free_req; - - /* Setting file->private_data can't race with other mount() - instances, since BKL is held for ->get_sb() */ + mutex_lock(&fuse_mutex); err = -EINVAL; if (file->private_data) - goto err_kobject_del; + 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; - kobject_get(&fc->kobj); - file->private_data = fc; + 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 @@ -548,15 +548,14 @@ static int fuse_fill_super(struct super_block *sb, void *data, int silent) return 0; - err_kobject_del: - kobject_del(&fc->kobj); - err_free_req: + err_unlock: + mutex_unlock(&fuse_mutex); fuse_request_free(init_req); err_put_root: dput(root_dentry); err: fput(file); - kobject_put(&fc->kobj); + fuse_conn_put(fc); return err; } @@ -574,68 +573,8 @@ static struct file_system_type fuse_fs_type = { .kill_sb = kill_anon_super, }; -static ssize_t fuse_conn_waiting_show(struct fuse_conn *fc, char *page) -{ - return sprintf(page, "%i\n", atomic_read(&fc->num_waiting)); -} - -static ssize_t fuse_conn_abort_store(struct fuse_conn *fc, const char *page, - size_t count) -{ - fuse_abort_conn(fc); - return count; -} - -static struct fuse_conn_attr fuse_conn_waiting = - __ATTR(waiting, 0400, fuse_conn_waiting_show, NULL); -static struct fuse_conn_attr fuse_conn_abort = - __ATTR(abort, 0600, NULL, fuse_conn_abort_store); - -static struct attribute *fuse_conn_attrs[] = { - &fuse_conn_waiting.attr, - &fuse_conn_abort.attr, - NULL, -}; - -static ssize_t fuse_conn_attr_show(struct kobject *kobj, - struct attribute *attr, - char *page) -{ - struct fuse_conn_attr *fca = - container_of(attr, struct fuse_conn_attr, attr); - - if (fca->show) - return fca->show(get_fuse_conn_kobj(kobj), page); - else - return -EACCES; -} - -static ssize_t fuse_conn_attr_store(struct kobject *kobj, - struct attribute *attr, - const char *page, size_t count) -{ - struct fuse_conn_attr *fca = - container_of(attr, struct fuse_conn_attr, attr); - - if (fca->store) - return fca->store(get_fuse_conn_kobj(kobj), page, count); - else - return -EACCES; -} - -static struct sysfs_ops fuse_conn_sysfs_ops = { - .show = &fuse_conn_attr_show, - .store = &fuse_conn_attr_store, -}; - -static struct kobj_type ktype_fuse_conn = { - .release = fuse_conn_release, - .sysfs_ops = &fuse_conn_sysfs_ops, - .default_attrs = fuse_conn_attrs, -}; - static decl_subsys(fuse, NULL, NULL); -static decl_subsys(connections, &ktype_fuse_conn, NULL); +static decl_subsys(connections, NULL, NULL); static void fuse_inode_init_once(void *foo, kmem_cache_t *cachep, unsigned long flags) @@ -709,6 +648,7 @@ static int __init fuse_init(void) 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; @@ -721,8 +661,14 @@ static int __init fuse_init(void) 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: @@ -735,6 +681,7 @@ static void __exit fuse_exit(void) { printk(KERN_DEBUG "fuse exit\n"); + fuse_ctl_cleanup(); fuse_sysfs_cleanup(); fuse_fs_cleanup(); fuse_dev_cleanup(); -- cgit v1.2.3