2 FUSE: Filesystem in Userspace
3 Copyright (C) 2001-2006 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 /** Maximum number of outstanding background requests */
22 #define FUSE_MAX_BACKGROUND 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 pending processing or io lists in
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 was interrupted */
154 unsigned interrupted:1;
156 /** Request is sent in the background */
157 unsigned background:1;
159 /** Data is being copied to/from the request */
162 /** State of the request */
163 enum fuse_req_state state;
165 /** The request input */
168 /** The request output */
171 /** Used to wake up the task waiting for completion of request*/
172 wait_queue_head_t waitq;
174 /** Data for asynchronous requests */
176 struct fuse_forget_in forget_in;
177 struct fuse_release_in release_in;
178 struct fuse_init_in init_in;
179 struct fuse_init_out init_out;
180 struct fuse_read_in read_in;
184 struct page *pages[FUSE_MAX_PAGES_PER_REQ];
186 /** number of pages in vector */
189 /** offset of data on first page */
190 unsigned page_offset;
192 /** Inode used in the request */
195 /** Second inode used in the request (or NULL) */
196 struct inode *inode2;
198 /** File used in the request (or NULL) */
201 /** Request completion callback */
202 void (*end)(struct fuse_conn *, struct fuse_req *);
208 * This structure is created, when the filesystem is mounted, and is
209 * destroyed, when the client device is closed and the filesystem is
213 /** Lock protecting accessess to members of this structure */
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 /** Number of requests currently in the background */
248 unsigned num_background;
250 /** Flag indicating if connection is blocked. This will be
251 the case before the INIT reply is received, and if there
252 are too many outstading backgrounds requests */
255 /** waitq for blocked connection */
256 wait_queue_head_t blocked_waitq;
258 /** RW semaphore for exclusion with fuse_put_super() */
259 struct rw_semaphore sbput_sem;
261 /** The next unique request id */
264 /** Mount is active */
267 /** Connection established, cleared on umount, connection
268 abort and device release */
271 /** Connection failed (version mismatch). Cannot race with
272 setting other bitfields since it is only set once in INIT
273 reply, before any other request, and never cleared */
274 unsigned conn_error : 1;
276 /** Do readpages asynchronously? Only set in INIT */
277 unsigned async_read : 1;
280 * The following bitfields are only for optimization purposes
281 * and hence races in setting them will not cause malfunction
284 /** Is fsync not implemented by fs? */
285 unsigned no_fsync : 1;
287 /** Is fsyncdir not implemented by fs? */
288 unsigned no_fsyncdir : 1;
290 /** Is flush not implemented by fs? */
291 unsigned no_flush : 1;
293 /** Is setxattr not implemented by fs? */
294 unsigned no_setxattr : 1;
296 /** Is getxattr not implemented by fs? */
297 unsigned no_getxattr : 1;
299 /** Is listxattr not implemented by fs? */
300 unsigned no_listxattr : 1;
302 /** Is removexattr not implemented by fs? */
303 unsigned no_removexattr : 1;
305 /** Is access not implemented by fs? */
306 unsigned no_access : 1;
308 /** Is create not implemented by fs? */
309 unsigned no_create : 1;
311 /** The number of requests waiting for completion */
312 atomic_t num_waiting;
314 /** Negotiated minor version */
317 /** Backing dev info */
318 struct backing_dev_info bdi;
323 /** O_ASYNC requests */
324 struct fasync_struct *fasync;
327 static inline struct fuse_conn *get_fuse_conn_super(struct super_block *sb)
329 return sb->s_fs_info;
332 static inline struct fuse_conn *get_fuse_conn(struct inode *inode)
334 return get_fuse_conn_super(inode->i_sb);
337 static inline struct fuse_conn *get_fuse_conn_kobj(struct kobject *obj)
339 return container_of(obj, struct fuse_conn, kobj);
342 static inline struct fuse_inode *get_fuse_inode(struct inode *inode)
344 return container_of(inode, struct fuse_inode, inode);
347 static inline u64 get_node_id(struct inode *inode)
349 return get_fuse_inode(inode)->nodeid;
352 /** Device operations */
353 extern const struct file_operations fuse_dev_operations;
356 * Get a filled in inode
358 struct inode *fuse_iget(struct super_block *sb, unsigned long nodeid,
359 int generation, struct fuse_attr *attr);
362 * Send FORGET command
364 void fuse_send_forget(struct fuse_conn *fc, struct fuse_req *req,
365 unsigned long nodeid, u64 nlookup);
368 * Initialize READ or READDIR request
370 void fuse_read_fill(struct fuse_req *req, struct file *file,
371 struct inode *inode, loff_t pos, size_t count, int opcode);
374 * Send OPEN or OPENDIR request
376 int fuse_open_common(struct inode *inode, struct file *file, int isdir);
378 struct fuse_file *fuse_file_alloc(void);
379 void fuse_file_free(struct fuse_file *ff);
380 void fuse_finish_open(struct inode *inode, struct file *file,
381 struct fuse_file *ff, struct fuse_open_out *outarg);
384 * Send a RELEASE request
386 void fuse_send_release(struct fuse_conn *fc, struct fuse_file *ff,
387 u64 nodeid, struct inode *inode, int flags, int isdir);
390 * Send RELEASE or RELEASEDIR request
392 int fuse_release_common(struct inode *inode, struct file *file, int isdir);
395 * Send FSYNC or FSYNCDIR request
397 int fuse_fsync_common(struct file *file, struct dentry *de, int datasync,
401 * Initialize file operations on a regular file
403 void fuse_init_file_inode(struct inode *inode);
406 * Initialize inode operations on regular files and special files
408 void fuse_init_common(struct inode *inode);
411 * Initialize inode and file operations on a directory
413 void fuse_init_dir(struct inode *inode);
416 * Initialize inode operations on a symlink
418 void fuse_init_symlink(struct inode *inode);
421 * Change attributes of an inode
423 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr);
426 * Initialize the client device
428 int fuse_dev_init(void);
431 * Cleanup the client device
433 void fuse_dev_cleanup(void);
438 struct fuse_req *fuse_request_alloc(void);
443 void fuse_request_free(struct fuse_req *req);
446 * Reinitialize a request, the preallocated flag is left unmodified
448 void fuse_reset_request(struct fuse_req *req);
451 * Reserve a preallocated request
453 struct fuse_req *fuse_get_req(struct fuse_conn *fc);
456 * Decrement reference count of a request. If count goes to zero free
459 void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req);
462 * Send a request (synchronous)
464 void request_send(struct fuse_conn *fc, struct fuse_req *req);
467 * Send a request with no reply
469 void request_send_noreply(struct fuse_conn *fc, struct fuse_req *req);
472 * Send a request in the background
474 void request_send_background(struct fuse_conn *fc, struct fuse_req *req);
477 * Release inodes and file associated with background request
479 void fuse_release_background(struct fuse_conn *fc, struct fuse_req *req);
481 /* Abort all requests */
482 void fuse_abort_conn(struct fuse_conn *fc);
485 * Get the attributes of a file
487 int fuse_do_getattr(struct inode *inode);
490 * Invalidate inode attributes
492 void fuse_invalidate_attr(struct inode *inode);