[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/fuse_i.h b/fs/fuse/fuse_i.h
index 25f8581..ac12b01 100644
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -14,6 +14,7 @@
#include <linux/spinlock.h>
#include <linux/mm.h>
#include <linux/backing-dev.h>
+#include <linux/mutex.h>
/** Max number of pages that can be used in a single read request */
#define FUSE_MAX_PAGES_PER_REQ 32
@@ -24,6 +25,9 @@
/** It could be as large as PATH_MAX, but would that have any uses? */
#define FUSE_NAME_MAX 1024
+/** Number of dentries for each connection in the control filesystem */
+#define FUSE_CTL_NUM_DENTRIES 3
+
/** If the FUSE_DEFAULT_PERMISSIONS flag is given, the filesystem
module will check permissions based on the file mode. Otherwise no
permission checking is done in the kernel */
@@ -33,6 +37,11 @@
doing the mount will be allowed to access the filesystem */
#define FUSE_ALLOW_OTHER (1 << 1)
+/** List of active connections */
+extern struct list_head fuse_conn_list;
+
+/** Global mutex protecting fuse_conn_list and the control filesystem */
+extern struct mutex fuse_mutex;
/** FUSE inode */
struct fuse_inode {
@@ -216,6 +225,9 @@
/** Lock protecting accessess to members of this structure */
spinlock_t lock;
+ /** Refcount */
+ atomic_t count;
+
/** The user id for this mount */
uid_t user_id;
@@ -310,8 +322,17 @@
/** Backing dev info */
struct backing_dev_info bdi;
- /** kobject */
- struct kobject kobj;
+ /** Entry on the fuse_conn_list */
+ struct list_head entry;
+
+ /** Unique ID */
+ u64 id;
+
+ /** Dentries in the control filesystem */
+ struct dentry *ctl_dentry[FUSE_CTL_NUM_DENTRIES];
+
+ /** number of dentries used in the above array */
+ int ctl_ndents;
/** O_ASYNC requests */
struct fasync_struct *fasync;
@@ -327,11 +348,6 @@
return get_fuse_conn_super(inode->i_sb);
}
-static inline struct fuse_conn *get_fuse_conn_kobj(struct kobject *obj)
-{
- return container_of(obj, struct fuse_conn, kobj);
-}
-
static inline struct fuse_inode *get_fuse_inode(struct inode *inode)
{
return container_of(inode, struct fuse_inode, inode);
@@ -422,6 +438,9 @@
*/
void fuse_dev_cleanup(void);
+int fuse_ctl_init(void);
+void fuse_ctl_cleanup(void);
+
/**
* Allocate a request
*/
@@ -470,3 +489,23 @@
* Invalidate inode attributes
*/
void fuse_invalidate_attr(struct inode *inode);
+
+/**
+ * Acquire reference to fuse_conn
+ */
+struct fuse_conn *fuse_conn_get(struct fuse_conn *fc);
+
+/**
+ * Release reference to fuse_conn
+ */
+void fuse_conn_put(struct fuse_conn *fc);
+
+/**
+ * Add connection to control filesystem
+ */
+int fuse_ctl_add_conn(struct fuse_conn *fc);
+
+/**
+ * Remove connection from control filesystem
+ */
+void fuse_ctl_remove_conn(struct fuse_conn *fc);