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;
172 struct fuse_read_in read_in;
176 struct page *pages[FUSE_MAX_PAGES_PER_REQ];
178 /** number of pages in vector */
181 /** offset of data on first page */
182 unsigned page_offset;
184 /** Inode used in the request */
187 /** Second inode used in the request (or NULL) */
188 struct inode *inode2;
190 /** File used in the request (or NULL) */
193 /** Request completion callback */
194 void (*end)(struct fuse_conn *, struct fuse_req *);
200 * This structure is created, when the filesystem is mounted, and is
201 * destroyed, when the client device is closed and the filesystem is
205 /** The user id for this mount */
208 /** The group id for this mount */
211 /** The fuse mount flags for this mount */
214 /** Maximum read size */
217 /** Maximum write size */
220 /** Readers of the connection are waiting on this */
221 wait_queue_head_t waitq;
223 /** The list of pending requests */
224 struct list_head pending;
226 /** The list of requests being processed */
227 struct list_head processing;
229 /** The list of requests under I/O */
232 /** Requests put in the background (RELEASE or any other
233 interrupted request) */
234 struct list_head background;
236 /** Controls the maximum number of outstanding requests */
237 struct semaphore outstanding_sem;
239 /** This counts the number of outstanding requests if
240 outstanding_sem would go negative */
241 unsigned outstanding_debt;
243 /** RW semaphore for exclusion with fuse_put_super() */
244 struct rw_semaphore sbput_sem;
246 /** The list of unused requests */
247 struct list_head unused_list;
249 /** The next unique request id */
252 /** Mount is active */
253 unsigned mounted : 1;
255 /** Connection established, cleared on umount, connection
256 abort and device release */
257 unsigned connected : 1;
259 /** Connection failed (version mismatch) */
260 unsigned conn_error : 1;
262 /** Is fsync not implemented by fs? */
263 unsigned no_fsync : 1;
265 /** Is fsyncdir not implemented by fs? */
266 unsigned no_fsyncdir : 1;
268 /** Is flush not implemented by fs? */
269 unsigned no_flush : 1;
271 /** Is setxattr not implemented by fs? */
272 unsigned no_setxattr : 1;
274 /** Is getxattr not implemented by fs? */
275 unsigned no_getxattr : 1;
277 /** Is listxattr not implemented by fs? */
278 unsigned no_listxattr : 1;
280 /** Is removexattr not implemented by fs? */
281 unsigned no_removexattr : 1;
283 /** Is access not implemented by fs? */
284 unsigned no_access : 1;
286 /** Is create not implemented by fs? */
287 unsigned no_create : 1;
289 /** The number of requests waiting for completion */
290 atomic_t num_waiting;
292 /** Negotiated minor version */
295 /** Backing dev info */
296 struct backing_dev_info bdi;
302 static inline struct fuse_conn *get_fuse_conn_super(struct super_block *sb)
304 return sb->s_fs_info;
307 static inline struct fuse_conn *get_fuse_conn(struct inode *inode)
309 return get_fuse_conn_super(inode->i_sb);
312 static inline struct fuse_conn *get_fuse_conn_kobj(struct kobject *obj)
314 return container_of(obj, struct fuse_conn, kobj);
317 static inline struct fuse_inode *get_fuse_inode(struct inode *inode)
319 return container_of(inode, struct fuse_inode, inode);
322 static inline u64 get_node_id(struct inode *inode)
324 return get_fuse_inode(inode)->nodeid;
327 /** Device operations */
328 extern struct file_operations fuse_dev_operations;
331 * This is the single global spinlock which protects FUSE's structures
333 * The following data is protected by this lock:
335 * - the private_data field of the device file
336 * - the s_fs_info field of the super block
337 * - unused_list, pending, processing lists in fuse_conn
338 * - background list in fuse_conn
339 * - the unique request ID counter reqctr in fuse_conn
340 * - the sb (super_block) field in fuse_conn
341 * - the file (device file) field in fuse_conn
343 extern spinlock_t fuse_lock;
346 * Get a filled in inode
348 struct inode *fuse_iget(struct super_block *sb, unsigned long nodeid,
349 int generation, struct fuse_attr *attr);
352 * Send FORGET command
354 void fuse_send_forget(struct fuse_conn *fc, struct fuse_req *req,
355 unsigned long nodeid, u64 nlookup);
358 * Initialize READ or READDIR request
360 void fuse_read_fill(struct fuse_req *req, struct file *file,
361 struct inode *inode, loff_t pos, size_t count, int opcode);
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);