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[PATCH] fuse: add control filesystem

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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>
This commit is contained in:
Miklos Szeredi
2006-06-25 05:48:51 -07:00
committed by Linus Torvalds
parent 51eb01e735
commit bafa96541b
6 changed files with 331 additions and 115 deletions
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141
fs/fuse/inode.c
View File

@@ -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();