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];
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 init_in
;
163 struct fuse_init_out init_out
;
167 struct page
*pages
[FUSE_MAX_PAGES_PER_REQ
];
169 /** number of pages in vector */
172 /** offset of data on first page */
173 unsigned page_offset
;
175 /** Inode used in the request */
178 /** Second inode used in the request (or NULL) */
179 struct inode
*inode2
;
181 /** File used in the request (or NULL) */
188 * This structure is created, when the filesystem is mounted, and is
189 * destroyed, when the client device is closed and the filesystem is
193 /** Reference count */
196 /** The user id for this mount */
199 /** The group id for this mount */
202 /** The fuse mount flags for this mount */
205 /** Maximum read size */
208 /** Maximum write size */
211 /** Readers of the connection are waiting on this */
212 wait_queue_head_t waitq
;
214 /** The list of pending requests */
215 struct list_head pending
;
217 /** The list of requests being processed */
218 struct list_head processing
;
220 /** Requests put in the background (RELEASE or any other
221 interrupted request) */
222 struct list_head background
;
224 /** Controls the maximum number of outstanding requests */
225 struct semaphore outstanding_sem
;
227 /** This counts the number of outstanding requests if
228 outstanding_sem would go negative */
229 unsigned outstanding_debt
;
231 /** RW semaphore for exclusion with fuse_put_super() */
232 struct rw_semaphore sbput_sem
;
234 /** The list of unused requests */
235 struct list_head unused_list
;
237 /** The next unique request id */
240 /** Mount is active */
241 unsigned mounted
: 1;
243 /** Connection established */
244 unsigned connected
: 1;
246 /** Connection failed (version mismatch) */
247 unsigned conn_error
: 1;
249 /** Is fsync not implemented by fs? */
250 unsigned no_fsync
: 1;
252 /** Is fsyncdir not implemented by fs? */
253 unsigned no_fsyncdir
: 1;
255 /** Is flush not implemented by fs? */
256 unsigned no_flush
: 1;
258 /** Is setxattr not implemented by fs? */
259 unsigned no_setxattr
: 1;
261 /** Is getxattr not implemented by fs? */
262 unsigned no_getxattr
: 1;
264 /** Is listxattr not implemented by fs? */
265 unsigned no_listxattr
: 1;
267 /** Is removexattr not implemented by fs? */
268 unsigned no_removexattr
: 1;
270 /** Is access not implemented by fs? */
271 unsigned no_access
: 1;
273 /** Is create not implemented by fs? */
274 unsigned no_create
: 1;
276 /** Negotiated minor version */
279 /** Backing dev info */
280 struct backing_dev_info bdi
;
283 static inline struct fuse_conn
**get_fuse_conn_super_p(struct super_block
*sb
)
285 return (struct fuse_conn
**) &sb
->s_fs_info
;
288 static inline struct fuse_conn
*get_fuse_conn_super(struct super_block
*sb
)
290 return *get_fuse_conn_super_p(sb
);
293 static inline struct fuse_conn
*get_fuse_conn(struct inode
*inode
)
295 return get_fuse_conn_super(inode
->i_sb
);
298 static inline struct fuse_inode
*get_fuse_inode(struct inode
*inode
)
300 return container_of(inode
, struct fuse_inode
, inode
);
303 static inline u64
get_node_id(struct inode
*inode
)
305 return get_fuse_inode(inode
)->nodeid
;
308 /** Device operations */
309 extern struct file_operations fuse_dev_operations
;
312 * This is the single global spinlock which protects FUSE's structures
314 * The following data is protected by this lock:
316 * - the private_data field of the device file
317 * - the s_fs_info field of the super block
318 * - unused_list, pending, processing lists in fuse_conn
319 * - background list in fuse_conn
320 * - the unique request ID counter reqctr in fuse_conn
321 * - the sb (super_block) field in fuse_conn
322 * - the file (device file) field in fuse_conn
324 extern spinlock_t fuse_lock
;
327 * Get a filled in inode
329 struct inode
*fuse_iget(struct super_block
*sb
, unsigned long nodeid
,
330 int generation
, struct fuse_attr
*attr
);
333 * Send FORGET command
335 void fuse_send_forget(struct fuse_conn
*fc
, struct fuse_req
*req
,
336 unsigned long nodeid
, u64 nlookup
);
339 * Send READ or READDIR request
341 size_t fuse_send_read_common(struct fuse_req
*req
, struct file
*file
,
342 struct inode
*inode
, loff_t pos
, size_t count
,
346 * Send OPEN or OPENDIR request
348 int fuse_open_common(struct inode
*inode
, struct file
*file
, int isdir
);
350 struct fuse_file
*fuse_file_alloc(void);
351 void fuse_file_free(struct fuse_file
*ff
);
352 void fuse_finish_open(struct inode
*inode
, struct file
*file
,
353 struct fuse_file
*ff
, struct fuse_open_out
*outarg
);
356 * Send a RELEASE request
358 void fuse_send_release(struct fuse_conn
*fc
, struct fuse_file
*ff
,
359 u64 nodeid
, struct inode
*inode
, int flags
, int isdir
);
362 * Send RELEASE or RELEASEDIR request
364 int fuse_release_common(struct inode
*inode
, struct file
*file
, int isdir
);
367 * Send FSYNC or FSYNCDIR request
369 int fuse_fsync_common(struct file
*file
, struct dentry
*de
, int datasync
,
373 * Initialize file operations on a regular file
375 void fuse_init_file_inode(struct inode
*inode
);
378 * Initialize inode operations on regular files and special files
380 void fuse_init_common(struct inode
*inode
);
383 * Initialize inode and file operations on a directory
385 void fuse_init_dir(struct inode
*inode
);
388 * Initialize inode operations on a symlink
390 void fuse_init_symlink(struct inode
*inode
);
393 * Change attributes of an inode
395 void fuse_change_attributes(struct inode
*inode
, struct fuse_attr
*attr
);
398 * Check if the connection can be released, and if yes, then free the
399 * connection structure
401 void fuse_release_conn(struct fuse_conn
*fc
);
404 * Initialize the client device
406 int fuse_dev_init(void);
409 * Cleanup the client device
411 void fuse_dev_cleanup(void);
416 struct fuse_req
*fuse_request_alloc(void);
421 void fuse_request_free(struct fuse_req
*req
);
424 * Reinitialize a request, the preallocated flag is left unmodified
426 void fuse_reset_request(struct fuse_req
*req
);
429 * Reserve a preallocated request
431 struct fuse_req
*fuse_get_request(struct fuse_conn
*fc
);
434 * Decrement reference count of a request. If count goes to zero put
435 * on unused list (preallocated) or free request (not preallocated).
437 void fuse_put_request(struct fuse_conn
*fc
, struct fuse_req
*req
);
440 * Send a request (synchronous)
442 void request_send(struct fuse_conn
*fc
, struct fuse_req
*req
);
445 * Send a request with no reply
447 void request_send_noreply(struct fuse_conn
*fc
, struct fuse_req
*req
);
450 * Send a request in the background
452 void request_send_background(struct fuse_conn
*fc
, struct fuse_req
*req
);
455 * Release inodes and file associated with background request
457 void fuse_release_background(struct fuse_req
*req
);
460 * Get the attributes of a file
462 int fuse_do_getattr(struct inode
*inode
);
465 * Invalidate inode attributes
467 void fuse_invalidate_attr(struct inode
*inode
);
470 * Send the INIT message
472 void fuse_send_init(struct fuse_conn
*fc
);