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)
33 /** If the FUSE_KERNEL_CACHE flag is given, then cached data will not
35 #define FUSE_KERNEL_CACHE (1 << 2)
37 /** Bypass the page cache for read and write operations */
38 #define FUSE_DIRECT_IO (1 << 3)
45 /** Unique ID, which identifies the inode between userspace
49 /** Number of lookups on this inode */
52 /** The request used for sending the FORGET message */
53 struct fuse_req
*forget_req
;
55 /** Time in jiffies until the file attributes are valid */
59 /** FUSE specific file data */
61 /** Request reserved for flush and release */
62 struct fuse_req
*release_req
;
64 /** File handle used by userspace */
68 /** One input argument of a request */
74 /** The request input */
76 /** The request header */
77 struct fuse_in_header h
;
79 /** True if the data for the last argument is in req->pages */
82 /** Number of arguments */
85 /** Array of arguments */
86 struct fuse_in_arg args
[3];
89 /** One output argument of a request */
95 /** The request output */
97 /** Header returned from userspace */
98 struct fuse_out_header h
;
100 /** Last argument is variable length (can be shorter than
104 /** Last argument is a list of pages to copy data to */
107 /** Zero partially or not copied pages */
108 unsigned page_zeroing
:1;
110 /** Number or arguments */
113 /** Array of arguments */
114 struct fuse_arg args
[3];
121 * A request to the client
124 /** This can be on either unused_list, pending or processing
125 lists in fuse_conn */
126 struct list_head list
;
128 /** Entry on the background list */
129 struct list_head bg_entry
;
134 /** True if the request has reply */
137 /** The request is preallocated */
138 unsigned preallocated
:1;
140 /** The request was interrupted */
141 unsigned interrupted
:1;
143 /** Request is sent in the background */
144 unsigned background
:1;
146 /** Data is being copied to/from the request */
149 /** Request has been sent to userspace */
152 /** The request is finished */
155 /** The request input */
158 /** The request output */
161 /** Used to wake up the task waiting for completion of request*/
162 wait_queue_head_t waitq
;
164 /** Data for asynchronous requests */
166 struct fuse_forget_in forget_in
;
167 struct fuse_release_in release_in
;
168 struct fuse_init_in_out init_in_out
;
172 struct page
*pages
[FUSE_MAX_PAGES_PER_REQ
];
174 /** number of pages in vector */
177 /** offset of data on first page */
178 unsigned page_offset
;
180 /** Inode used in the request */
183 /** Second inode used in the request (or NULL) */
184 struct inode
*inode2
;
186 /** File used in the request (or NULL) */
193 * This structure is created, when the filesystem is mounted, and is
194 * destroyed, when the client device is closed and the filesystem is
198 /** Reference count */
201 /** The user id for this mount */
204 /** The group id for this mount */
207 /** The fuse mount flags for this mount */
210 /** Maximum read size */
213 /** Maximum write size */
216 /** Readers of the connection are waiting on this */
217 wait_queue_head_t waitq
;
219 /** The list of pending requests */
220 struct list_head pending
;
222 /** The list of requests being processed */
223 struct list_head processing
;
225 /** Requests put in the background (RELEASE or any other
226 interrupted request) */
227 struct list_head background
;
229 /** Controls the maximum number of outstanding requests */
230 struct semaphore outstanding_sem
;
232 /** This counts the number of outstanding requests if
233 outstanding_sem would go negative */
234 unsigned outstanding_debt
;
236 /** RW semaphore for exclusion with fuse_put_super() */
237 struct rw_semaphore sbput_sem
;
239 /** The list of unused requests */
240 struct list_head unused_list
;
242 /** The next unique request id */
245 /** Mount is active */
246 unsigned mounted
: 1;
248 /** Connection established */
249 unsigned connected
: 1;
251 /** Connection failed (version mismatch) */
252 unsigned conn_error
: 1;
254 /** Is fsync not implemented by fs? */
255 unsigned no_fsync
: 1;
257 /** Is flush not implemented by fs? */
258 unsigned no_flush
: 1;
260 /** Is setxattr not implemented by fs? */
261 unsigned no_setxattr
: 1;
263 /** Is getxattr not implemented by fs? */
264 unsigned no_getxattr
: 1;
266 /** Is listxattr not implemented by fs? */
267 unsigned no_listxattr
: 1;
269 /** Is removexattr not implemented by fs? */
270 unsigned no_removexattr
: 1;
272 /** Backing dev info */
273 struct backing_dev_info bdi
;
276 struct fuse_getdir_out_i
{
278 void *file
; /* Used by kernel only */
281 static inline struct fuse_conn
**get_fuse_conn_super_p(struct super_block
*sb
)
283 return (struct fuse_conn
**) &sb
->s_fs_info
;
286 static inline struct fuse_conn
*get_fuse_conn_super(struct super_block
*sb
)
288 return *get_fuse_conn_super_p(sb
);
291 static inline struct fuse_conn
*get_fuse_conn(struct inode
*inode
)
293 return get_fuse_conn_super(inode
->i_sb
);
296 static inline struct fuse_inode
*get_fuse_inode(struct inode
*inode
)
298 return container_of(inode
, struct fuse_inode
, inode
);
301 static inline u64
get_node_id(struct inode
*inode
)
303 return get_fuse_inode(inode
)->nodeid
;
306 /** Device operations */
307 extern struct file_operations fuse_dev_operations
;
310 * This is the single global spinlock which protects FUSE's structures
312 * The following data is protected by this lock:
314 * - the private_data field of the device file
315 * - the s_fs_info field of the super block
316 * - unused_list, pending, processing lists in fuse_conn
317 * - background list in fuse_conn
318 * - the unique request ID counter reqctr in fuse_conn
319 * - the sb (super_block) field in fuse_conn
320 * - the file (device file) field in fuse_conn
322 extern spinlock_t fuse_lock
;
325 * Get a filled in inode
327 struct inode
*fuse_iget(struct super_block
*sb
, unsigned long nodeid
,
328 int generation
, struct fuse_attr
*attr
);
331 * Send FORGET command
333 void fuse_send_forget(struct fuse_conn
*fc
, struct fuse_req
*req
,
334 unsigned long nodeid
, u64 nlookup
);
337 * Initialise file operations on a regular file
339 void fuse_init_file_inode(struct inode
*inode
);
342 * Initialise inode operations on regular files and special files
344 void fuse_init_common(struct inode
*inode
);
347 * Initialise inode and file operations on a directory
349 void fuse_init_dir(struct inode
*inode
);
352 * Initialise inode operations on a symlink
354 void fuse_init_symlink(struct inode
*inode
);
357 * Change attributes of an inode
359 void fuse_change_attributes(struct inode
*inode
, struct fuse_attr
*attr
);
362 * Check if the connection can be released, and if yes, then free the
363 * connection structure
365 void fuse_release_conn(struct fuse_conn
*fc
);
368 * Initialize the client device
370 int fuse_dev_init(void);
373 * Cleanup the client device
375 void fuse_dev_cleanup(void);
380 struct fuse_req
*fuse_request_alloc(void);
385 void fuse_request_free(struct fuse_req
*req
);
388 * Reinitialize a request, the preallocated flag is left unmodified
390 void fuse_reset_request(struct fuse_req
*req
);
393 * Reserve a preallocated request
395 struct fuse_req
*fuse_get_request(struct fuse_conn
*fc
);
398 * Reserve a preallocated request, only interruptible by SIGKILL
400 struct fuse_req
*fuse_get_request_nonint(struct fuse_conn
*fc
);
403 * Decrement reference count of a request. If count goes to zero put
404 * on unused list (preallocated) or free reqest (not preallocated).
406 void fuse_put_request(struct fuse_conn
*fc
, struct fuse_req
*req
);
409 * Send a request (synchronous, interruptible)
411 void request_send(struct fuse_conn
*fc
, struct fuse_req
*req
);
414 * Send a request (synchronous, non-interruptible except by SIGKILL)
416 void request_send_nonint(struct fuse_conn
*fc
, struct fuse_req
*req
);
419 * Send a request with no reply
421 void request_send_noreply(struct fuse_conn
*fc
, struct fuse_req
*req
);
424 * Send a request in the background
426 void request_send_background(struct fuse_conn
*fc
, struct fuse_req
*req
);
429 * Release inodes and file assiciated with background request
431 void fuse_release_background(struct fuse_req
*req
);
434 * Get the attributes of a file
436 int fuse_do_getattr(struct inode
*inode
);
439 * Invalidate inode attributes
441 void fuse_invalidate_attr(struct inode
*inode
);
444 * Send the INIT message
446 void fuse_send_init(struct fuse_conn
*fc
);