[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 <miklos@szeredi.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
index 0225729..13a7e8a 100644
--- a/fs/fuse/inode.c
+++ b/fs/fuse/inode.c
@@ -22,13 +22,8 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
.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 @@
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 @@
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 @@
{
printk(KERN_DEBUG "fuse exit\n");
+ fuse_ctl_cleanup();
fuse_sysfs_cleanup();
fuse_fs_cleanup();
fuse_dev_cleanup();