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
;
97 /** Last argument is variable length (can be shorter than
101 /** Last argument is a list of pages to copy data to */
104 /** Zero partially or not copied pages */
105 unsigned page_zeroing
:1;
107 /** Number or arguments */
110 /** Array of arguments */
111 struct fuse_arg args
[3];
114 /** The request state */
115 enum fuse_req_state
{
126 * A request to the client
129 /** This can be on either unused_list, pending processing or
130 io lists in fuse_conn */
131 struct list_head list
;
133 /** Entry on the background list */
134 struct list_head bg_entry
;
139 /** True if the request has reply */
142 /** The request is preallocated */
143 unsigned preallocated
:1;
145 /** The request was interrupted */
146 unsigned interrupted
:1;
148 /** Request is sent in the background */
149 unsigned background
:1;
151 /** Data is being copied to/from the request */
154 /** State of the request */
155 enum fuse_req_state state
;
157 /** The request input */
160 /** The request output */
163 /** Used to wake up the task waiting for completion of request*/
164 wait_queue_head_t waitq
;
166 /** Data for asynchronous requests */
168 struct fuse_forget_in forget_in
;
169 struct fuse_release_in release_in
;
170 struct fuse_init_in init_in
;
171 struct fuse_init_out init_out
;
175 struct page
*pages
[FUSE_MAX_PAGES_PER_REQ
];
177 /** number of pages in vector */
180 /** offset of data on first page */
181 unsigned page_offset
;
183 /** Inode used in the request */
186 /** Second inode used in the request (or NULL) */
187 struct inode
*inode2
;
189 /** File used in the request (or NULL) */
192 /** Request completion callback */
193 void (*end
)(struct fuse_conn
*, struct fuse_req
*);
199 * This structure is created, when the filesystem is mounted, and is
200 * destroyed, when the client device is closed and the filesystem is
204 /** The user id for this mount */
207 /** The group id for this mount */
210 /** The fuse mount flags for this mount */
213 /** Maximum read size */
216 /** Maximum write size */
219 /** Readers of the connection are waiting on this */
220 wait_queue_head_t waitq
;
222 /** The list of pending requests */
223 struct list_head pending
;
225 /** The list of requests being processed */
226 struct list_head processing
;
228 /** The list of requests under I/O */
231 /** Requests put in the background (RELEASE or any other
232 interrupted request) */
233 struct list_head background
;
235 /** Controls the maximum number of outstanding requests */
236 struct semaphore outstanding_sem
;
238 /** This counts the number of outstanding requests if
239 outstanding_sem would go negative */
240 unsigned outstanding_debt
;
242 /** RW semaphore for exclusion with fuse_put_super() */
243 struct rw_semaphore sbput_sem
;
245 /** The list of unused requests */
246 struct list_head unused_list
;
248 /** The next unique request id */
251 /** Mount is active */
252 unsigned mounted
: 1;
254 /** Connection established, cleared on umount, connection
255 abort and device release */
256 unsigned connected
: 1;
258 /** Connection failed (version mismatch) */
259 unsigned conn_error
: 1;
261 /** Is fsync not implemented by fs? */
262 unsigned no_fsync
: 1;
264 /** Is fsyncdir not implemented by fs? */
265 unsigned no_fsyncdir
: 1;
267 /** Is flush not implemented by fs? */
268 unsigned no_flush
: 1;
270 /** Is setxattr not implemented by fs? */
271 unsigned no_setxattr
: 1;
273 /** Is getxattr not implemented by fs? */
274 unsigned no_getxattr
: 1;
276 /** Is listxattr not implemented by fs? */
277 unsigned no_listxattr
: 1;
279 /** Is removexattr not implemented by fs? */
280 unsigned no_removexattr
: 1;
282 /** Is access not implemented by fs? */
283 unsigned no_access
: 1;
285 /** Is create not implemented by fs? */
286 unsigned no_create
: 1;
288 /** The number of requests waiting for completion */
289 atomic_t num_waiting
;
291 /** Negotiated minor version */
294 /** Backing dev info */
295 struct backing_dev_info bdi
;
301 static inline struct fuse_conn
*get_fuse_conn_super(struct super_block
*sb
)
303 return sb
->s_fs_info
;
306 static inline struct fuse_conn
*get_fuse_conn(struct inode
*inode
)
308 return get_fuse_conn_super(inode
->i_sb
);
311 static inline struct fuse_conn
*get_fuse_conn_kobj(struct kobject
*obj
)
313 return container_of(obj
, struct fuse_conn
, kobj
);
316 static inline struct fuse_inode
*get_fuse_inode(struct inode
*inode
)
318 return container_of(inode
, struct fuse_inode
, inode
);
321 static inline u64
get_node_id(struct inode
*inode
)
323 return get_fuse_inode(inode
)->nodeid
;
326 /** Device operations */
327 extern struct file_operations fuse_dev_operations
;
330 * This is the single global spinlock which protects FUSE's structures
332 * The following data is protected by this lock:
334 * - the private_data field of the device file
335 * - the s_fs_info field of the super block
336 * - unused_list, pending, processing lists in fuse_conn
337 * - background list in fuse_conn
338 * - the unique request ID counter reqctr in fuse_conn
339 * - the sb (super_block) field in fuse_conn
340 * - the file (device file) field in fuse_conn
342 extern spinlock_t fuse_lock
;
345 * Get a filled in inode
347 struct inode
*fuse_iget(struct super_block
*sb
, unsigned long nodeid
,
348 int generation
, struct fuse_attr
*attr
);
351 * Send FORGET command
353 void fuse_send_forget(struct fuse_conn
*fc
, struct fuse_req
*req
,
354 unsigned long nodeid
, u64 nlookup
);
357 * Send READ or READDIR request
359 size_t fuse_send_read_common(struct fuse_req
*req
, struct file
*file
,
360 struct inode
*inode
, loff_t pos
, size_t count
,
364 * Send OPEN or OPENDIR request
366 int fuse_open_common(struct inode
*inode
, struct file
*file
, int isdir
);
368 struct fuse_file
*fuse_file_alloc(void);
369 void fuse_file_free(struct fuse_file
*ff
);
370 void fuse_finish_open(struct inode
*inode
, struct file
*file
,
371 struct fuse_file
*ff
, struct fuse_open_out
*outarg
);
374 * Send a RELEASE request
376 void fuse_send_release(struct fuse_conn
*fc
, struct fuse_file
*ff
,
377 u64 nodeid
, struct inode
*inode
, int flags
, int isdir
);
380 * Send RELEASE or RELEASEDIR request
382 int fuse_release_common(struct inode
*inode
, struct file
*file
, int isdir
);
385 * Send FSYNC or FSYNCDIR request
387 int fuse_fsync_common(struct file
*file
, struct dentry
*de
, int datasync
,
391 * Initialize file operations on a regular file
393 void fuse_init_file_inode(struct inode
*inode
);
396 * Initialize inode operations on regular files and special files
398 void fuse_init_common(struct inode
*inode
);
401 * Initialize inode and file operations on a directory
403 void fuse_init_dir(struct inode
*inode
);
406 * Initialize inode operations on a symlink
408 void fuse_init_symlink(struct inode
*inode
);
411 * Change attributes of an inode
413 void fuse_change_attributes(struct inode
*inode
, struct fuse_attr
*attr
);
416 * Initialize the client device
418 int fuse_dev_init(void);
421 * Cleanup the client device
423 void fuse_dev_cleanup(void);
428 struct fuse_req
*fuse_request_alloc(void);
433 void fuse_request_free(struct fuse_req
*req
);
436 * Reinitialize a request, the preallocated flag is left unmodified
438 void fuse_reset_request(struct fuse_req
*req
);
441 * Reserve a preallocated request
443 struct fuse_req
*fuse_get_request(struct fuse_conn
*fc
);
446 * Decrement reference count of a request. If count goes to zero put
447 * on unused list (preallocated) or free request (not preallocated).
449 void fuse_put_request(struct fuse_conn
*fc
, struct fuse_req
*req
);
452 * Send a request (synchronous)
454 void request_send(struct fuse_conn
*fc
, struct fuse_req
*req
);
457 * Send a request with no reply
459 void request_send_noreply(struct fuse_conn
*fc
, struct fuse_req
*req
);
462 * Send a request in the background
464 void request_send_background(struct fuse_conn
*fc
, struct fuse_req
*req
);
467 * Release inodes and file associated with background request
469 void fuse_release_background(struct fuse_req
*req
);
471 /* Abort all requests */
472 void fuse_abort_conn(struct fuse_conn
*fc
);
475 * Get the attributes of a file
477 int fuse_do_getattr(struct inode
*inode
);
480 * Invalidate inode attributes
482 void fuse_invalidate_attr(struct inode
*inode
);
485 * Send the INIT message
487 void fuse_send_init(struct fuse_conn
*fc
);