2 FUSE: Filesystem in Userspace
3 Copyright (C) 2001-2005 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/wait.h>
12 #include <linux/list.h>
13 #include <linux/spinlock.h>
15 #include <linux/backing-dev.h>
16 #include <asm/semaphore.h>
18 /** Max number of pages that can be used in a single read request */
19 #define FUSE_MAX_PAGES_PER_REQ 32
21 /** If more requests are outstanding, then the operation will block */
22 #define FUSE_MAX_OUTSTANDING 10
24 /** It could be as large as PATH_MAX, but would that have any uses? */
25 #define FUSE_NAME_MAX 1024
27 /** If the FUSE_DEFAULT_PERMISSIONS flag is given, the filesystem
28 module will check permissions based on the file mode. Otherwise no
29 permission checking is done in the kernel */
30 #define FUSE_DEFAULT_PERMISSIONS (1 << 0)
32 /** If the FUSE_ALLOW_OTHER flag is given, then not only the user
33 doing the mount will be allowed to access the filesystem */
34 #define FUSE_ALLOW_OTHER (1 << 1)
42 /** Unique ID, which identifies the inode between userspace
46 /** Number of lookups on this inode */
49 /** The request used for sending the FORGET message */
50 struct fuse_req
*forget_req
;
52 /** Time in jiffies until the file attributes are valid */
56 /** FUSE specific file data */
58 /** Request reserved for flush and release */
59 struct fuse_req
*release_req
;
61 /** File handle used by userspace */
65 /** One input argument of a request */
71 /** The request input */
73 /** The request header */
74 struct fuse_in_header h
;
76 /** True if the data for the last argument is in req->pages */
79 /** Number of arguments */
82 /** Array of arguments */
83 struct fuse_in_arg args
[3];
86 /** One output argument of a request */
92 /** The request output */
94 /** Header returned from userspace */
95 struct fuse_out_header h
;
98 * The following bitfields are not changed during the request
102 /** Last argument is variable length (can be shorter than
106 /** Last argument is a list of pages to copy data to */
109 /** Zero partially or not copied pages */
110 unsigned page_zeroing
:1;
112 /** Number or arguments */
115 /** Array of arguments */
116 struct fuse_arg args
[3];
119 /** The request state */
120 enum fuse_req_state
{
131 * A request to the client
134 /** This can be on either unused_list, pending processing or
135 io lists in fuse_conn */
136 struct list_head list
;
138 /** Entry on the background list */
139 struct list_head bg_entry
;
145 * The following bitfields are either set once before the
146 * request is queued or setting/clearing them is protected by
150 /** True if the request has reply */
153 /** The request is preallocated */
154 unsigned preallocated
:1;
156 /** The request was interrupted */
157 unsigned interrupted
:1;
159 /** Request is sent in the background */
160 unsigned background
:1;
162 /** Data is being copied to/from the request */
165 /** State of the request */
166 enum fuse_req_state state
;
168 /** The request input */
171 /** The request output */
174 /** Used to wake up the task waiting for completion of request*/
175 wait_queue_head_t waitq
;
177 /** Data for asynchronous requests */
179 struct fuse_forget_in forget_in
;
180 struct fuse_release_in release_in
;
181 struct fuse_init_in init_in
;
182 struct fuse_init_out init_out
;
183 struct fuse_read_in read_in
;
187 struct page
*pages
[FUSE_MAX_PAGES_PER_REQ
];
189 /** number of pages in vector */
192 /** offset of data on first page */
193 unsigned page_offset
;
195 /** Inode used in the request */
198 /** Second inode used in the request (or NULL) */
199 struct inode
*inode2
;
201 /** File used in the request (or NULL) */
204 /** Request completion callback */
205 void (*end
)(struct fuse_conn
*, struct fuse_req
*);
211 * This structure is created, when the filesystem is mounted, and is
212 * destroyed, when the client device is closed and the filesystem is
216 /** The user id for this mount */
219 /** The group id for this mount */
222 /** The fuse mount flags for this mount */
225 /** Maximum read size */
228 /** Maximum write size */
231 /** Readers of the connection are waiting on this */
232 wait_queue_head_t waitq
;
234 /** The list of pending requests */
235 struct list_head pending
;
237 /** The list of requests being processed */
238 struct list_head processing
;
240 /** The list of requests under I/O */
243 /** Requests put in the background (RELEASE or any other
244 interrupted request) */
245 struct list_head background
;
247 /** Controls the maximum number of outstanding requests */
248 struct semaphore outstanding_sem
;
250 /** This counts the number of outstanding requests if
251 outstanding_sem would go negative */
252 unsigned outstanding_debt
;
254 /** RW semaphore for exclusion with fuse_put_super() */
255 struct rw_semaphore sbput_sem
;
257 /** The list of unused requests */
258 struct list_head unused_list
;
260 /** The next unique request id */
263 /** Mount is active */
266 /** Connection established, cleared on umount, connection
267 abort and device release */
270 /** Connection failed (version mismatch). Cannot race with
271 setting other bitfields since it is only set once in INIT
272 reply, before any other request, and never cleared */
273 unsigned conn_error
: 1;
276 * The following bitfields are only for optimization purposes
277 * and hence races in setting them will not cause malfunction
280 /** Is fsync not implemented by fs? */
281 unsigned no_fsync
: 1;
283 /** Is fsyncdir not implemented by fs? */
284 unsigned no_fsyncdir
: 1;
286 /** Is flush not implemented by fs? */
287 unsigned no_flush
: 1;
289 /** Is setxattr not implemented by fs? */
290 unsigned no_setxattr
: 1;
292 /** Is getxattr not implemented by fs? */
293 unsigned no_getxattr
: 1;
295 /** Is listxattr not implemented by fs? */
296 unsigned no_listxattr
: 1;
298 /** Is removexattr not implemented by fs? */
299 unsigned no_removexattr
: 1;
301 /** Is access not implemented by fs? */
302 unsigned no_access
: 1;
304 /** Is create not implemented by fs? */
305 unsigned no_create
: 1;
307 /** The number of requests waiting for completion */
308 atomic_t num_waiting
;
310 /** Negotiated minor version */
313 /** Backing dev info */
314 struct backing_dev_info bdi
;
320 static inline struct fuse_conn
*get_fuse_conn_super(struct super_block
*sb
)
322 return sb
->s_fs_info
;
325 static inline struct fuse_conn
*get_fuse_conn(struct inode
*inode
)
327 return get_fuse_conn_super(inode
->i_sb
);
330 static inline struct fuse_conn
*get_fuse_conn_kobj(struct kobject
*obj
)
332 return container_of(obj
, struct fuse_conn
, kobj
);
335 static inline struct fuse_inode
*get_fuse_inode(struct inode
*inode
)
337 return container_of(inode
, struct fuse_inode
, inode
);
340 static inline u64
get_node_id(struct inode
*inode
)
342 return get_fuse_inode(inode
)->nodeid
;
345 /** Device operations */
346 extern struct file_operations fuse_dev_operations
;
349 * This is the single global spinlock which protects FUSE's structures
351 * The following data is protected by this lock:
353 * - the private_data field of the device file
354 * - the s_fs_info field of the super block
355 * - unused_list, pending, processing lists in fuse_conn
356 * - background list in fuse_conn
357 * - the unique request ID counter reqctr in fuse_conn
358 * - the sb (super_block) field in fuse_conn
359 * - the file (device file) field in fuse_conn
361 extern spinlock_t fuse_lock
;
364 * Get a filled in inode
366 struct inode
*fuse_iget(struct super_block
*sb
, unsigned long nodeid
,
367 int generation
, struct fuse_attr
*attr
);
370 * Send FORGET command
372 void fuse_send_forget(struct fuse_conn
*fc
, struct fuse_req
*req
,
373 unsigned long nodeid
, u64 nlookup
);
376 * Initialize READ or READDIR request
378 void fuse_read_fill(struct fuse_req
*req
, struct file
*file
,
379 struct inode
*inode
, loff_t pos
, size_t count
, int opcode
);
382 * Send OPEN or OPENDIR request
384 int fuse_open_common(struct inode
*inode
, struct file
*file
, int isdir
);
386 struct fuse_file
*fuse_file_alloc(void);
387 void fuse_file_free(struct fuse_file
*ff
);
388 void fuse_finish_open(struct inode
*inode
, struct file
*file
,
389 struct fuse_file
*ff
, struct fuse_open_out
*outarg
);
392 * Send a RELEASE request
394 void fuse_send_release(struct fuse_conn
*fc
, struct fuse_file
*ff
,
395 u64 nodeid
, struct inode
*inode
, int flags
, int isdir
);
398 * Send RELEASE or RELEASEDIR request
400 int fuse_release_common(struct inode
*inode
, struct file
*file
, int isdir
);
403 * Send FSYNC or FSYNCDIR request
405 int fuse_fsync_common(struct file
*file
, struct dentry
*de
, int datasync
,
409 * Initialize file operations on a regular file
411 void fuse_init_file_inode(struct inode
*inode
);
414 * Initialize inode operations on regular files and special files
416 void fuse_init_common(struct inode
*inode
);
419 * Initialize inode and file operations on a directory
421 void fuse_init_dir(struct inode
*inode
);
424 * Initialize inode operations on a symlink
426 void fuse_init_symlink(struct inode
*inode
);
429 * Change attributes of an inode
431 void fuse_change_attributes(struct inode
*inode
, struct fuse_attr
*attr
);
434 * Initialize the client device
436 int fuse_dev_init(void);
439 * Cleanup the client device
441 void fuse_dev_cleanup(void);
446 struct fuse_req
*fuse_request_alloc(void);
451 void fuse_request_free(struct fuse_req
*req
);
454 * Reinitialize a request, the preallocated flag is left unmodified
456 void fuse_reset_request(struct fuse_req
*req
);
459 * Reserve a preallocated request
461 struct fuse_req
*fuse_get_request(struct fuse_conn
*fc
);
464 * Decrement reference count of a request. If count goes to zero put
465 * on unused list (preallocated) or free request (not preallocated).
467 void fuse_put_request(struct fuse_conn
*fc
, struct fuse_req
*req
);
470 * Send a request (synchronous)
472 void request_send(struct fuse_conn
*fc
, struct fuse_req
*req
);
475 * Send a request with no reply
477 void request_send_noreply(struct fuse_conn
*fc
, struct fuse_req
*req
);
480 * Send a request in the background
482 void request_send_background(struct fuse_conn
*fc
, struct fuse_req
*req
);
485 * Release inodes and file associated with background request
487 void fuse_release_background(struct fuse_req
*req
);
489 /* Abort all requests */
490 void fuse_abort_conn(struct fuse_conn
*fc
);
493 * Get the attributes of a file
495 int fuse_do_getattr(struct inode
*inode
);
498 * Invalidate inode attributes
500 void fuse_invalidate_attr(struct inode
*inode
);