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>
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;
142 * The following bitfields are either set once before the
143 * request is queued or setting/clearing them is protected by
147 /** True if the request has reply */
150 /** Force sending of the request even if interrupted */
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 /** Request is counted as "waiting" */
165 /** State of the request */
166 enum fuse_req_state state;
168 /** The request input */
171 /** The request output */
174 /** Used to wake up the task waiting for completion of request*/
175 wait_queue_head_t waitq;
177 /** Data for asynchronous requests */
179 struct fuse_forget_in forget_in;
180 struct fuse_release_in release_in;
181 struct fuse_init_in init_in;
182 struct fuse_init_out init_out;
183 struct fuse_read_in read_in;
187 struct page *pages[FUSE_MAX_PAGES_PER_REQ];
189 /** number of pages in vector */
192 /** offset of data on first page */
193 unsigned page_offset;
195 /** File used in the request (or NULL) */
198 /** vfsmount used in release */
199 struct vfsmount *vfsmount;
201 /** dentry used in release */
202 struct dentry *dentry;
204 /** Request completion callback */
205 void (*end)(struct fuse_conn *, struct fuse_req *);
211 * This structure is created, when the filesystem is mounted, and is
212 * destroyed, when the client device is closed and the filesystem is
216 /** Lock protecting accessess to members of this structure */
219 /** The user id for this mount */
222 /** The group id for this mount */
225 /** The fuse mount flags for this mount */
228 /** Maximum read size */
231 /** Maximum write size */
234 /** Readers of the connection are waiting on this */
235 wait_queue_head_t waitq;
237 /** The list of pending requests */
238 struct list_head pending;
240 /** The list of requests being processed */
241 struct list_head processing;
243 /** The list of requests under I/O */
246 /** Number of requests currently in the background */
247 unsigned num_background;
249 /** Flag indicating if connection is blocked. This will be
250 the case before the INIT reply is received, and if there
251 are too many outstading backgrounds requests */
254 /** waitq for blocked connection */
255 wait_queue_head_t blocked_waitq;
257 /** The next unique request id */
260 /** Connection established, cleared on umount, connection
261 abort and device release */
264 /** Connection failed (version mismatch). Cannot race with
265 setting other bitfields since it is only set once in INIT
266 reply, before any other request, and never cleared */
267 unsigned conn_error : 1;
269 /** Do readpages asynchronously? Only set in INIT */
270 unsigned async_read : 1;
273 * The following bitfields are only for optimization purposes
274 * and hence races in setting them will not cause malfunction
277 /** Is fsync not implemented by fs? */
278 unsigned no_fsync : 1;
280 /** Is fsyncdir not implemented by fs? */
281 unsigned no_fsyncdir : 1;
283 /** Is flush not implemented by fs? */
284 unsigned no_flush : 1;
286 /** Is setxattr not implemented by fs? */
287 unsigned no_setxattr : 1;
289 /** Is getxattr not implemented by fs? */
290 unsigned no_getxattr : 1;
292 /** Is listxattr not implemented by fs? */
293 unsigned no_listxattr : 1;
295 /** Is removexattr not implemented by fs? */
296 unsigned no_removexattr : 1;
298 /** Is access not implemented by fs? */
299 unsigned no_access : 1;
301 /** Is create not implemented by fs? */
302 unsigned no_create : 1;
304 /** The number of requests waiting for completion */
305 atomic_t num_waiting;
307 /** Negotiated minor version */
310 /** Backing dev info */
311 struct backing_dev_info bdi;
316 /** O_ASYNC requests */
317 struct fasync_struct *fasync;
320 static inline struct fuse_conn *get_fuse_conn_super(struct super_block *sb)
322 return sb->s_fs_info;
325 static inline struct fuse_conn *get_fuse_conn(struct inode *inode)
327 return get_fuse_conn_super(inode->i_sb);
330 static inline struct fuse_conn *get_fuse_conn_kobj(struct kobject *obj)
332 return container_of(obj, struct fuse_conn, kobj);
335 static inline struct fuse_inode *get_fuse_inode(struct inode *inode)
337 return container_of(inode, struct fuse_inode, inode);
340 static inline u64 get_node_id(struct inode *inode)
342 return get_fuse_inode(inode)->nodeid;
345 /** Device operations */
346 extern const struct file_operations fuse_dev_operations;
349 * Get a filled in inode
351 struct inode *fuse_iget(struct super_block *sb, unsigned long nodeid,
352 int generation, struct fuse_attr *attr);
355 * Send FORGET command
357 void fuse_send_forget(struct fuse_conn *fc, struct fuse_req *req,
358 unsigned long nodeid, u64 nlookup);
361 * Initialize READ or READDIR request
363 void fuse_read_fill(struct fuse_req *req, struct file *file,
364 struct inode *inode, loff_t pos, size_t count, int opcode);
367 * Send OPEN or OPENDIR request
369 int fuse_open_common(struct inode *inode, struct file *file, int isdir);
371 struct fuse_file *fuse_file_alloc(void);
372 void fuse_file_free(struct fuse_file *ff);
373 void fuse_finish_open(struct inode *inode, struct file *file,
374 struct fuse_file *ff, struct fuse_open_out *outarg);
377 struct fuse_req *fuse_release_fill(struct fuse_file *ff, u64 nodeid, int flags,
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 * Reserve a preallocated request
438 struct fuse_req *fuse_get_req(struct fuse_conn *fc);
441 * Decrement reference count of a request. If count goes to zero free
444 void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req);
447 * Send a request (synchronous)
449 void request_send(struct fuse_conn *fc, struct fuse_req *req);
452 * Send a request with no reply
454 void request_send_noreply(struct fuse_conn *fc, struct fuse_req *req);
457 * Send a request in the background
459 void request_send_background(struct fuse_conn *fc, struct fuse_req *req);
461 /* Abort all requests */
462 void fuse_abort_conn(struct fuse_conn *fc);
465 * Get the attributes of a file
467 int fuse_do_getattr(struct inode *inode);
470 * Invalidate inode attributes
472 void fuse_invalidate_attr(struct inode *inode);