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 /** If the FUSE_DEFAULT_PERMISSIONS flag is given, the filesystem
25 module will check permissions based on the file mode. Otherwise no
26 permission checking is done in the kernel */
27 #define FUSE_DEFAULT_PERMISSIONS (1 << 0)
29 /** If the FUSE_ALLOW_OTHER flag is given, then not only the user
30 doing the mount will be allowed to access the filesystem */
31 #define FUSE_ALLOW_OTHER (1 << 1)
39 /** Unique ID, which identifies the inode between userspace
43 /** Number of lookups on this inode */
46 /** The request used for sending the FORGET message */
47 struct fuse_req
*forget_req
;
49 /** Time in jiffies until the file attributes are valid */
53 /** FUSE specific file data */
55 /** Request reserved for flush and release */
56 struct fuse_req
*release_req
;
58 /** File handle used by userspace */
62 /** One input argument of a request */
68 /** The request input */
70 /** The request header */
71 struct fuse_in_header h
;
73 /** True if the data for the last argument is in req->pages */
76 /** Number of arguments */
79 /** Array of arguments */
80 struct fuse_in_arg args
[3];
83 /** One output argument of a request */
89 /** The request output */
91 /** Header returned from userspace */
92 struct fuse_out_header h
;
94 /** Last argument is variable length (can be shorter than
98 /** Last argument is a list of pages to copy data to */
101 /** Zero partially or not copied pages */
102 unsigned page_zeroing
:1;
104 /** Number or arguments */
107 /** Array of arguments */
108 struct fuse_arg args
[3];
115 * A request to the client
118 /** This can be on either unused_list, pending or processing
119 lists in fuse_conn */
120 struct list_head list
;
122 /** Entry on the background list */
123 struct list_head bg_entry
;
128 /** True if the request has reply */
131 /** The request is preallocated */
132 unsigned preallocated
:1;
134 /** The request was interrupted */
135 unsigned interrupted
:1;
137 /** Request is sent in the background */
138 unsigned background
:1;
140 /** Data is being copied to/from the request */
143 /** Request has been sent to userspace */
146 /** The request is finished */
149 /** The request input */
152 /** The request output */
155 /** Used to wake up the task waiting for completion of request*/
156 wait_queue_head_t waitq
;
158 /** Data for asynchronous requests */
160 struct fuse_forget_in forget_in
;
161 struct fuse_release_in release_in
;
162 struct fuse_init_in_out init_in_out
;
166 struct page
*pages
[FUSE_MAX_PAGES_PER_REQ
];
168 /** number of pages in vector */
171 /** offset of data on first page */
172 unsigned page_offset
;
174 /** Inode used in the request */
177 /** Second inode used in the request (or NULL) */
178 struct inode
*inode2
;
180 /** File used in the request (or NULL) */
187 * This structure is created, when the filesystem is mounted, and is
188 * destroyed, when the client device is closed and the filesystem is
192 /** Reference count */
195 /** The user id for this mount */
198 /** The group id for this mount */
201 /** The fuse mount flags for this mount */
204 /** Maximum read size */
207 /** Maximum write size */
210 /** Readers of the connection are waiting on this */
211 wait_queue_head_t waitq
;
213 /** The list of pending requests */
214 struct list_head pending
;
216 /** The list of requests being processed */
217 struct list_head processing
;
219 /** Requests put in the background (RELEASE or any other
220 interrupted request) */
221 struct list_head background
;
223 /** Controls the maximum number of outstanding requests */
224 struct semaphore outstanding_sem
;
226 /** This counts the number of outstanding requests if
227 outstanding_sem would go negative */
228 unsigned outstanding_debt
;
230 /** RW semaphore for exclusion with fuse_put_super() */
231 struct rw_semaphore sbput_sem
;
233 /** The list of unused requests */
234 struct list_head unused_list
;
236 /** The next unique request id */
239 /** Mount is active */
240 unsigned mounted
: 1;
242 /** Connection established */
243 unsigned connected
: 1;
245 /** Connection failed (version mismatch) */
246 unsigned conn_error
: 1;
248 /** Is fsync not implemented by fs? */
249 unsigned no_fsync
: 1;
251 /** Is flush not implemented by fs? */
252 unsigned no_flush
: 1;
254 /** Is setxattr not implemented by fs? */
255 unsigned no_setxattr
: 1;
257 /** Is getxattr not implemented by fs? */
258 unsigned no_getxattr
: 1;
260 /** Is listxattr not implemented by fs? */
261 unsigned no_listxattr
: 1;
263 /** Is removexattr not implemented by fs? */
264 unsigned no_removexattr
: 1;
266 /** Backing dev info */
267 struct backing_dev_info bdi
;
270 static inline struct fuse_conn
**get_fuse_conn_super_p(struct super_block
*sb
)
272 return (struct fuse_conn
**) &sb
->s_fs_info
;
275 static inline struct fuse_conn
*get_fuse_conn_super(struct super_block
*sb
)
277 return *get_fuse_conn_super_p(sb
);
280 static inline struct fuse_conn
*get_fuse_conn(struct inode
*inode
)
282 return get_fuse_conn_super(inode
->i_sb
);
285 static inline struct fuse_inode
*get_fuse_inode(struct inode
*inode
)
287 return container_of(inode
, struct fuse_inode
, inode
);
290 static inline u64
get_node_id(struct inode
*inode
)
292 return get_fuse_inode(inode
)->nodeid
;
295 /** Device operations */
296 extern struct file_operations fuse_dev_operations
;
299 * This is the single global spinlock which protects FUSE's structures
301 * The following data is protected by this lock:
303 * - the private_data field of the device file
304 * - the s_fs_info field of the super block
305 * - unused_list, pending, processing lists in fuse_conn
306 * - background list in fuse_conn
307 * - the unique request ID counter reqctr in fuse_conn
308 * - the sb (super_block) field in fuse_conn
309 * - the file (device file) field in fuse_conn
311 extern spinlock_t fuse_lock
;
314 * Get a filled in inode
316 struct inode
*fuse_iget(struct super_block
*sb
, unsigned long nodeid
,
317 int generation
, struct fuse_attr
*attr
);
320 * Send FORGET command
322 void fuse_send_forget(struct fuse_conn
*fc
, struct fuse_req
*req
,
323 unsigned long nodeid
, u64 nlookup
);
326 * Send READ or READDIR request
328 size_t fuse_send_read_common(struct fuse_req
*req
, struct file
*file
,
329 struct inode
*inode
, loff_t pos
, size_t count
,
333 * Send OPEN or OPENDIR request
335 int fuse_open_common(struct inode
*inode
, struct file
*file
, int isdir
);
338 * Send RELEASE or RELEASEDIR request
340 int fuse_release_common(struct inode
*inode
, struct file
*file
, int isdir
);
343 * Initialise file operations on a regular file
345 void fuse_init_file_inode(struct inode
*inode
);
348 * Initialise inode operations on regular files and special files
350 void fuse_init_common(struct inode
*inode
);
353 * Initialise inode and file operations on a directory
355 void fuse_init_dir(struct inode
*inode
);
358 * Initialise inode operations on a symlink
360 void fuse_init_symlink(struct inode
*inode
);
363 * Change attributes of an inode
365 void fuse_change_attributes(struct inode
*inode
, struct fuse_attr
*attr
);
368 * Check if the connection can be released, and if yes, then free the
369 * connection structure
371 void fuse_release_conn(struct fuse_conn
*fc
);
374 * Initialize the client device
376 int fuse_dev_init(void);
379 * Cleanup the client device
381 void fuse_dev_cleanup(void);
386 struct fuse_req
*fuse_request_alloc(void);
391 void fuse_request_free(struct fuse_req
*req
);
394 * Reinitialize a request, the preallocated flag is left unmodified
396 void fuse_reset_request(struct fuse_req
*req
);
399 * Reserve a preallocated request
401 struct fuse_req
*fuse_get_request(struct fuse_conn
*fc
);
404 * Reserve a preallocated request, only interruptible by SIGKILL
406 struct fuse_req
*fuse_get_request_nonint(struct fuse_conn
*fc
);
409 * Decrement reference count of a request. If count goes to zero put
410 * on unused list (preallocated) or free reqest (not preallocated).
412 void fuse_put_request(struct fuse_conn
*fc
, struct fuse_req
*req
);
415 * Send a request (synchronous, interruptible)
417 void request_send(struct fuse_conn
*fc
, struct fuse_req
*req
);
420 * Send a request (synchronous, non-interruptible except by SIGKILL)
422 void request_send_nonint(struct fuse_conn
*fc
, struct fuse_req
*req
);
425 * Send a request with no reply
427 void request_send_noreply(struct fuse_conn
*fc
, struct fuse_req
*req
);
430 * Send a request in the background
432 void request_send_background(struct fuse_conn
*fc
, struct fuse_req
*req
);
435 * Release inodes and file assiciated with background request
437 void fuse_release_background(struct fuse_req
*req
);
440 * Get the attributes of a file
442 int fuse_do_getattr(struct inode
*inode
);
445 * Invalidate inode attributes
447 void fuse_invalidate_attr(struct inode
*inode
);
450 * Send the INIT message
452 void fuse_send_init(struct fuse_conn
*fc
);