2 FUSE: Filesystem in Userspace
3 Copyright (C) 2001-2006 Miklos Szeredi <miklos@szeredi.hu>
5 This program can be distributed under the terms of the GNU GPL.
9 #include <linux/fuse.h>
11 #include <linux/mount.h>
12 #include <linux/wait.h>
13 #include <linux/list.h>
14 #include <linux/spinlock.h>
16 #include <linux/backing-dev.h>
17 #include <linux/mutex.h>
19 /** Max number of pages that can be used in a single read request */
20 #define FUSE_MAX_PAGES_PER_REQ 32
22 /** Maximum number of outstanding background requests */
23 #define FUSE_MAX_BACKGROUND 10
25 /** It could be as large as PATH_MAX, but would that have any uses? */
26 #define FUSE_NAME_MAX 1024
28 /** Number of dentries for each connection in the control filesystem */
29 #define FUSE_CTL_NUM_DENTRIES 3
31 /** If the FUSE_DEFAULT_PERMISSIONS flag is given, the filesystem
32 module will check permissions based on the file mode. Otherwise no
33 permission checking is done in the kernel */
34 #define FUSE_DEFAULT_PERMISSIONS (1 << 0)
36 /** If the FUSE_ALLOW_OTHER flag is given, then not only the user
37 doing the mount will be allowed to access the filesystem */
38 #define FUSE_ALLOW_OTHER (1 << 1)
40 /** List of active connections */
41 extern struct list_head fuse_conn_list;
43 /** Global mutex protecting fuse_conn_list and the control filesystem */
44 extern struct mutex fuse_mutex;
51 /** Unique ID, which identifies the inode between userspace
55 /** Number of lookups on this inode */
58 /** The request used for sending the FORGET message */
59 struct fuse_req *forget_req;
61 /** Time in jiffies until the file attributes are valid */
65 /** FUSE specific file data */
67 /** Request reserved for flush and release */
68 struct fuse_req *release_req;
70 /** File handle used by userspace */
74 /** One input argument of a request */
80 /** The request input */
82 /** The request header */
83 struct fuse_in_header h;
85 /** True if the data for the last argument is in req->pages */
88 /** Number of arguments */
91 /** Array of arguments */
92 struct fuse_in_arg args[3];
95 /** One output argument of a request */
101 /** The request output */
103 /** Header returned from userspace */
104 struct fuse_out_header h;
107 * The following bitfields are not changed during the request
111 /** Last argument is variable length (can be shorter than
115 /** Last argument is a list of pages to copy data to */
118 /** Zero partially or not copied pages */
119 unsigned page_zeroing:1;
121 /** Number or arguments */
124 /** Array of arguments */
125 struct fuse_arg args[3];
128 /** The request state */
129 enum fuse_req_state {
140 * A request to the client
143 /** This can be on either pending processing or io lists in
145 struct list_head list;
151 * The following bitfields are either set once before the
152 * request is queued or setting/clearing them is protected by
156 /** True if the request has reply */
159 /** Force sending of the request even if interrupted */
162 /** The request was interrupted */
163 unsigned interrupted:1;
165 /** Request is sent in the background */
166 unsigned background:1;
168 /** Data is being copied to/from the request */
171 /** Request is counted as "waiting" */
174 /** State of the request */
175 enum fuse_req_state state;
177 /** The request input */
180 /** The request output */
183 /** Used to wake up the task waiting for completion of request*/
184 wait_queue_head_t waitq;
186 /** Data for asynchronous requests */
188 struct fuse_forget_in forget_in;
189 struct fuse_release_in release_in;
190 struct fuse_init_in init_in;
191 struct fuse_init_out init_out;
192 struct fuse_read_in read_in;
196 struct page *pages[FUSE_MAX_PAGES_PER_REQ];
198 /** number of pages in vector */
201 /** offset of data on first page */
202 unsigned page_offset;
204 /** File used in the request (or NULL) */
207 /** vfsmount used in release */
208 struct vfsmount *vfsmount;
210 /** dentry used in release */
211 struct dentry *dentry;
213 /** Request completion callback */
214 void (*end)(struct fuse_conn *, struct fuse_req *);
220 * This structure is created, when the filesystem is mounted, and is
221 * destroyed, when the client device is closed and the filesystem is
225 /** Lock protecting accessess to members of this structure */
231 /** The user id for this mount */
234 /** The group id for this mount */
237 /** The fuse mount flags for this mount */
240 /** Maximum read size */
243 /** Maximum write size */
246 /** Readers of the connection are waiting on this */
247 wait_queue_head_t waitq;
249 /** The list of pending requests */
250 struct list_head pending;
252 /** The list of requests being processed */
253 struct list_head processing;
255 /** The list of requests under I/O */
258 /** Number of requests currently in the background */
259 unsigned num_background;
261 /** Flag indicating if connection is blocked. This will be
262 the case before the INIT reply is received, and if there
263 are too many outstading backgrounds requests */
266 /** waitq for blocked connection */
267 wait_queue_head_t blocked_waitq;
269 /** The next unique request id */
272 /** Connection established, cleared on umount, connection
273 abort and device release */
276 /** Connection failed (version mismatch). Cannot race with
277 setting other bitfields since it is only set once in INIT
278 reply, before any other request, and never cleared */
279 unsigned conn_error : 1;
281 /** Do readpages asynchronously? Only set in INIT */
282 unsigned async_read : 1;
285 * The following bitfields are only for optimization purposes
286 * and hence races in setting them will not cause malfunction
289 /** Is fsync not implemented by fs? */
290 unsigned no_fsync : 1;
292 /** Is fsyncdir not implemented by fs? */
293 unsigned no_fsyncdir : 1;
295 /** Is flush not implemented by fs? */
296 unsigned no_flush : 1;
298 /** Is setxattr not implemented by fs? */
299 unsigned no_setxattr : 1;
301 /** Is getxattr not implemented by fs? */
302 unsigned no_getxattr : 1;
304 /** Is listxattr not implemented by fs? */
305 unsigned no_listxattr : 1;
307 /** Is removexattr not implemented by fs? */
308 unsigned no_removexattr : 1;
310 /** Is access not implemented by fs? */
311 unsigned no_access : 1;
313 /** Is create not implemented by fs? */
314 unsigned no_create : 1;
316 /** The number of requests waiting for completion */
317 atomic_t num_waiting;
319 /** Negotiated minor version */
322 /** Backing dev info */
323 struct backing_dev_info bdi;
325 /** Entry on the fuse_conn_list */
326 struct list_head entry;
331 /** Dentries in the control filesystem */
332 struct dentry *ctl_dentry[FUSE_CTL_NUM_DENTRIES];
334 /** number of dentries used in the above array */
337 /** O_ASYNC requests */
338 struct fasync_struct *fasync;
341 static inline struct fuse_conn *get_fuse_conn_super(struct super_block *sb)
343 return sb->s_fs_info;
346 static inline struct fuse_conn *get_fuse_conn(struct inode *inode)
348 return get_fuse_conn_super(inode->i_sb);
351 static inline struct fuse_inode *get_fuse_inode(struct inode *inode)
353 return container_of(inode, struct fuse_inode, inode);
356 static inline u64 get_node_id(struct inode *inode)
358 return get_fuse_inode(inode)->nodeid;
361 /** Device operations */
362 extern const struct file_operations fuse_dev_operations;
365 * Get a filled in inode
367 struct inode *fuse_iget(struct super_block *sb, unsigned long nodeid,
368 int generation, struct fuse_attr *attr);
371 * Send FORGET command
373 void fuse_send_forget(struct fuse_conn *fc, struct fuse_req *req,
374 unsigned long nodeid, u64 nlookup);
377 * Initialize READ or READDIR request
379 void fuse_read_fill(struct fuse_req *req, struct file *file,
380 struct inode *inode, loff_t pos, size_t count, int opcode);
383 * Send OPEN or OPENDIR request
385 int fuse_open_common(struct inode *inode, struct file *file, int isdir);
387 struct fuse_file *fuse_file_alloc(void);
388 void fuse_file_free(struct fuse_file *ff);
389 void fuse_finish_open(struct inode *inode, struct file *file,
390 struct fuse_file *ff, struct fuse_open_out *outarg);
393 struct fuse_req *fuse_release_fill(struct fuse_file *ff, u64 nodeid, int flags,
396 * Send RELEASE or RELEASEDIR request
398 int fuse_release_common(struct inode *inode, struct file *file, int isdir);
401 * Send FSYNC or FSYNCDIR request
403 int fuse_fsync_common(struct file *file, struct dentry *de, int datasync,
407 * Initialize file operations on a regular file
409 void fuse_init_file_inode(struct inode *inode);
412 * Initialize inode operations on regular files and special files
414 void fuse_init_common(struct inode *inode);
417 * Initialize inode and file operations on a directory
419 void fuse_init_dir(struct inode *inode);
422 * Initialize inode operations on a symlink
424 void fuse_init_symlink(struct inode *inode);
427 * Change attributes of an inode
429 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr);
432 * Initialize the client device
434 int fuse_dev_init(void);
437 * Cleanup the client device
439 void fuse_dev_cleanup(void);
441 int fuse_ctl_init(void);
442 void fuse_ctl_cleanup(void);
447 struct fuse_req *fuse_request_alloc(void);
452 void fuse_request_free(struct fuse_req *req);
455 * Reserve a preallocated request
457 struct fuse_req *fuse_get_req(struct fuse_conn *fc);
460 * Decrement reference count of a request. If count goes to zero free
463 void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req);
466 * Send a request (synchronous)
468 void request_send(struct fuse_conn *fc, struct fuse_req *req);
471 * Send a request with no reply
473 void request_send_noreply(struct fuse_conn *fc, struct fuse_req *req);
476 * Send a request in the background
478 void request_send_background(struct fuse_conn *fc, struct fuse_req *req);
480 /* Abort all requests */
481 void fuse_abort_conn(struct fuse_conn *fc);
484 * Get the attributes of a file
486 int fuse_do_getattr(struct inode *inode);
489 * Invalidate inode attributes
491 void fuse_invalidate_attr(struct inode *inode);
494 * Acquire reference to fuse_conn
496 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc);
499 * Release reference to fuse_conn
501 void fuse_conn_put(struct fuse_conn *fc);
504 * Add connection to control filesystem
506 int fuse_ctl_add_conn(struct fuse_conn *fc);
509 * Remove connection from control filesystem
511 void fuse_ctl_remove_conn(struct fuse_conn *fc);