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/mount.h>
12 #include <linux/wait.h>
13 #include <linux/list.h>
14 #include <linux/spinlock.h>
16 #include <linux/backing-dev.h>
17 #include <linux/mutex.h>
19 /** Max number of pages that can be used in a single read request */
20 #define FUSE_MAX_PAGES_PER_REQ 32
22 /** Maximum number of outstanding background requests */
23 #define FUSE_MAX_BACKGROUND 12
25 /** Congestion starts at 75% of maximum */
26 #define FUSE_CONGESTION_THRESHOLD (FUSE_MAX_BACKGROUND * 75 / 100)
28 /** It could be as large as PATH_MAX, but would that have any uses? */
29 #define FUSE_NAME_MAX 1024
31 /** Number of dentries for each connection in the control filesystem */
32 #define FUSE_CTL_NUM_DENTRIES 3
34 /** If the FUSE_DEFAULT_PERMISSIONS flag is given, the filesystem
35 module will check permissions based on the file mode. Otherwise no
36 permission checking is done in the kernel */
37 #define FUSE_DEFAULT_PERMISSIONS (1 << 0)
39 /** If the FUSE_ALLOW_OTHER flag is given, then not only the user
40 doing the mount will be allowed to access the filesystem */
41 #define FUSE_ALLOW_OTHER (1 << 1)
43 /** List of active connections */
44 extern struct list_head fuse_conn_list;
46 /** Global mutex protecting fuse_conn_list and the control filesystem */
47 extern struct mutex fuse_mutex;
54 /** Unique ID, which identifies the inode between userspace
58 /** Number of lookups on this inode */
61 /** The request used for sending the FORGET message */
62 struct fuse_req *forget_req;
64 /** Time in jiffies until the file attributes are valid */
68 /** FUSE specific file data */
70 /** Request reserved for flush and release */
71 struct fuse_req *reserved_req;
73 /** File handle used by userspace */
77 /** One input argument of a request */
83 /** The request input */
85 /** The request header */
86 struct fuse_in_header h;
88 /** True if the data for the last argument is in req->pages */
91 /** Number of arguments */
94 /** Array of arguments */
95 struct fuse_in_arg args[3];
98 /** One output argument of a request */
104 /** The request output */
106 /** Header returned from userspace */
107 struct fuse_out_header h;
110 * The following bitfields are not changed during the request
114 /** Last argument is variable length (can be shorter than
118 /** Last argument is a list of pages to copy data to */
121 /** Zero partially or not copied pages */
122 unsigned page_zeroing:1;
124 /** Number or arguments */
127 /** Array of arguments */
128 struct fuse_arg args[3];
131 /** The request state */
132 enum fuse_req_state {
144 * A request to the client
147 /** This can be on either pending processing or io lists in
149 struct list_head list;
151 /** Entry on the interrupts list */
152 struct list_head intr_entry;
157 /** Unique ID for the interrupt request */
161 * The following bitfields are either set once before the
162 * request is queued or setting/clearing them is protected by
166 /** True if the request has reply */
169 /** Force sending of the request even if interrupted */
172 /** The request was aborted */
175 /** Request is sent in the background */
176 unsigned background:1;
178 /** The request has been interrupted */
179 unsigned interrupted:1;
181 /** Data is being copied to/from the request */
184 /** Request is counted as "waiting" */
187 /** State of the request */
188 enum fuse_req_state state;
190 /** The request input */
193 /** The request output */
196 /** Used to wake up the task waiting for completion of request*/
197 wait_queue_head_t waitq;
199 /** Data for asynchronous requests */
201 struct fuse_forget_in forget_in;
202 struct fuse_release_in release_in;
203 struct fuse_init_in init_in;
204 struct fuse_init_out init_out;
205 struct fuse_read_in read_in;
206 struct fuse_lk_in lk_in;
210 struct page *pages[FUSE_MAX_PAGES_PER_REQ];
212 /** number of pages in vector */
215 /** offset of data on first page */
216 unsigned page_offset;
218 /** File used in the request (or NULL) */
221 /** vfsmount used in release */
222 struct vfsmount *vfsmount;
224 /** dentry used in release */
225 struct dentry *dentry;
227 /** Request completion callback */
228 void (*end)(struct fuse_conn *, struct fuse_req *);
230 /** Request is stolen from fuse_file->reserved_req */
231 struct file *stolen_file;
237 * This structure is created, when the filesystem is mounted, and is
238 * destroyed, when the client device is closed and the filesystem is
242 /** Lock protecting accessess to members of this structure */
245 /** Mutex protecting against directory alias creation */
246 struct mutex inst_mutex;
251 /** The user id for this mount */
254 /** The group id for this mount */
257 /** The fuse mount flags for this mount */
260 /** Maximum read size */
263 /** Maximum write size */
266 /** Readers of the connection are waiting on this */
267 wait_queue_head_t waitq;
269 /** The list of pending requests */
270 struct list_head pending;
272 /** The list of requests being processed */
273 struct list_head processing;
275 /** The list of requests under I/O */
278 /** Number of requests currently in the background */
279 unsigned num_background;
281 /** Pending interrupts */
282 struct list_head interrupts;
284 /** Flag indicating if connection is blocked. This will be
285 the case before the INIT reply is received, and if there
286 are too many outstading backgrounds requests */
289 /** waitq for blocked connection */
290 wait_queue_head_t blocked_waitq;
292 /** waitq for reserved requests */
293 wait_queue_head_t reserved_req_waitq;
295 /** The next unique request id */
298 /** Connection established, cleared on umount, connection
299 abort and device release */
302 /** Connection failed (version mismatch). Cannot race with
303 setting other bitfields since it is only set once in INIT
304 reply, before any other request, and never cleared */
305 unsigned conn_error : 1;
307 /** Connection successful. Only set in INIT */
308 unsigned conn_init : 1;
310 /** Do readpages asynchronously? Only set in INIT */
311 unsigned async_read : 1;
314 * The following bitfields are only for optimization purposes
315 * and hence races in setting them will not cause malfunction
318 /** Is fsync not implemented by fs? */
319 unsigned no_fsync : 1;
321 /** Is fsyncdir not implemented by fs? */
322 unsigned no_fsyncdir : 1;
324 /** Is flush not implemented by fs? */
325 unsigned no_flush : 1;
327 /** Is setxattr not implemented by fs? */
328 unsigned no_setxattr : 1;
330 /** Is getxattr not implemented by fs? */
331 unsigned no_getxattr : 1;
333 /** Is listxattr not implemented by fs? */
334 unsigned no_listxattr : 1;
336 /** Is removexattr not implemented by fs? */
337 unsigned no_removexattr : 1;
339 /** Are file locking primitives not implemented by fs? */
340 unsigned no_lock : 1;
342 /** Is access not implemented by fs? */
343 unsigned no_access : 1;
345 /** Is create not implemented by fs? */
346 unsigned no_create : 1;
348 /** Is interrupt not implemented by fs? */
349 unsigned no_interrupt : 1;
351 /** Is bmap not implemented by fs? */
352 unsigned no_bmap : 1;
354 /** The number of requests waiting for completion */
355 atomic_t num_waiting;
357 /** Negotiated minor version */
360 /** Backing dev info */
361 struct backing_dev_info bdi;
363 /** Entry on the fuse_conn_list */
364 struct list_head entry;
369 /** Dentries in the control filesystem */
370 struct dentry *ctl_dentry[FUSE_CTL_NUM_DENTRIES];
372 /** number of dentries used in the above array */
375 /** O_ASYNC requests */
376 struct fasync_struct *fasync;
378 /** Key for lock owner ID scrambling */
381 /** Reserved request for the DESTROY message */
382 struct fuse_req *destroy_req;
385 static inline struct fuse_conn *get_fuse_conn_super(struct super_block *sb)
387 return sb->s_fs_info;
390 static inline struct fuse_conn *get_fuse_conn(struct inode *inode)
392 return get_fuse_conn_super(inode->i_sb);
395 static inline struct fuse_inode *get_fuse_inode(struct inode *inode)
397 return container_of(inode, struct fuse_inode, inode);
400 static inline u64 get_node_id(struct inode *inode)
402 return get_fuse_inode(inode)->nodeid;
405 /** Device operations */
406 extern const struct file_operations fuse_dev_operations;
409 * Get a filled in inode
411 struct inode *fuse_iget(struct super_block *sb, unsigned long nodeid,
412 int generation, struct fuse_attr *attr);
415 * Send FORGET command
417 void fuse_send_forget(struct fuse_conn *fc, struct fuse_req *req,
418 unsigned long nodeid, u64 nlookup);
421 * Initialize READ or READDIR request
423 void fuse_read_fill(struct fuse_req *req, struct file *file,
424 struct inode *inode, loff_t pos, size_t count, int opcode);
427 * Send OPEN or OPENDIR request
429 int fuse_open_common(struct inode *inode, struct file *file, int isdir);
431 struct fuse_file *fuse_file_alloc(void);
432 void fuse_file_free(struct fuse_file *ff);
433 void fuse_finish_open(struct inode *inode, struct file *file,
434 struct fuse_file *ff, struct fuse_open_out *outarg);
437 struct fuse_req *fuse_release_fill(struct fuse_file *ff, u64 nodeid, int flags,
440 * Send RELEASE or RELEASEDIR request
442 int fuse_release_common(struct inode *inode, struct file *file, int isdir);
445 * Send FSYNC or FSYNCDIR request
447 int fuse_fsync_common(struct file *file, struct dentry *de, int datasync,
451 * Initialize file operations on a regular file
453 void fuse_init_file_inode(struct inode *inode);
456 * Initialize inode operations on regular files and special files
458 void fuse_init_common(struct inode *inode);
461 * Initialize inode and file operations on a directory
463 void fuse_init_dir(struct inode *inode);
466 * Initialize inode operations on a symlink
468 void fuse_init_symlink(struct inode *inode);
471 * Change attributes of an inode
473 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr);
476 * Initialize the client device
478 int fuse_dev_init(void);
481 * Cleanup the client device
483 void fuse_dev_cleanup(void);
485 int fuse_ctl_init(void);
486 void fuse_ctl_cleanup(void);
491 struct fuse_req *fuse_request_alloc(void);
496 void fuse_request_free(struct fuse_req *req);
499 * Get a request, may fail with -ENOMEM
501 struct fuse_req *fuse_get_req(struct fuse_conn *fc);
504 * Gets a requests for a file operation, always succeeds
506 struct fuse_req *fuse_get_req_nofail(struct fuse_conn *fc, struct file *file);
509 * Decrement reference count of a request. If count goes to zero free
512 void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req);
515 * Send a request (synchronous)
517 void request_send(struct fuse_conn *fc, struct fuse_req *req);
520 * Send a request with no reply
522 void request_send_noreply(struct fuse_conn *fc, struct fuse_req *req);
525 * Send a request in the background
527 void request_send_background(struct fuse_conn *fc, struct fuse_req *req);
529 /* Abort all requests */
530 void fuse_abort_conn(struct fuse_conn *fc);
533 * Get the attributes of a file
535 int fuse_do_getattr(struct inode *inode);
538 * Invalidate inode attributes
540 void fuse_invalidate_attr(struct inode *inode);
543 * Acquire reference to fuse_conn
545 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc);
548 * Release reference to fuse_conn
550 void fuse_conn_put(struct fuse_conn *fc);
553 * Add connection to control filesystem
555 int fuse_ctl_add_conn(struct fuse_conn *fc);
558 * Remove connection from control filesystem
560 void fuse_ctl_remove_conn(struct fuse_conn *fc);
563 * Is file type valid?
565 int fuse_valid_type(int m);