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 {
124 * A request to the client
127 /** This can be on either unused_list, pending processing or
128 io lists in fuse_conn */
129 struct list_head list;
131 /** Entry on the background list */
132 struct list_head bg_entry;
137 /** True if the request has reply */
140 /** The request is preallocated */
141 unsigned preallocated:1;
143 /** The request was interrupted */
144 unsigned interrupted:1;
146 /** Request is sent in the background */
147 unsigned background:1;
149 /** Data is being copied to/from the request */
152 /** State of the request */
153 enum fuse_req_state state;
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 init_in;
169 struct fuse_init_out init_out;
173 struct page *pages[FUSE_MAX_PAGES_PER_REQ];
175 /** number of pages in vector */
178 /** offset of data on first page */
179 unsigned page_offset;
181 /** Inode used in the request */
184 /** Second inode used in the request (or NULL) */
185 struct inode *inode2;
187 /** File used in the request (or NULL) */
194 * This structure is created, when the filesystem is mounted, and is
195 * destroyed, when the client device is closed and the filesystem is
199 /** The user id for this mount */
202 /** The group id for this mount */
205 /** The fuse mount flags for this mount */
208 /** Maximum read size */
211 /** Maximum write size */
214 /** Readers of the connection are waiting on this */
215 wait_queue_head_t waitq;
217 /** The list of pending requests */
218 struct list_head pending;
220 /** The list of requests being processed */
221 struct list_head processing;
223 /** The list of requests under I/O */
226 /** Requests put in the background (RELEASE or any other
227 interrupted request) */
228 struct list_head background;
230 /** Controls the maximum number of outstanding requests */
231 struct semaphore outstanding_sem;
233 /** This counts the number of outstanding requests if
234 outstanding_sem would go negative */
235 unsigned outstanding_debt;
237 /** RW semaphore for exclusion with fuse_put_super() */
238 struct rw_semaphore sbput_sem;
240 /** The list of unused requests */
241 struct list_head unused_list;
243 /** The next unique request id */
246 /** Mount is active */
247 unsigned mounted : 1;
249 /** Connection established, cleared on umount and device
251 unsigned connected : 1;
253 /** Connection failed (version mismatch) */
254 unsigned conn_error : 1;
256 /** Is fsync not implemented by fs? */
257 unsigned no_fsync : 1;
259 /** Is fsyncdir not implemented by fs? */
260 unsigned no_fsyncdir : 1;
262 /** Is flush not implemented by fs? */
263 unsigned no_flush : 1;
265 /** Is setxattr not implemented by fs? */
266 unsigned no_setxattr : 1;
268 /** Is getxattr not implemented by fs? */
269 unsigned no_getxattr : 1;
271 /** Is listxattr not implemented by fs? */
272 unsigned no_listxattr : 1;
274 /** Is removexattr not implemented by fs? */
275 unsigned no_removexattr : 1;
277 /** Is access not implemented by fs? */
278 unsigned no_access : 1;
280 /** Is create not implemented by fs? */
281 unsigned no_create : 1;
283 /** The number of requests waiting for completion */
284 atomic_t num_waiting;
286 /** Negotiated minor version */
289 /** Backing dev info */
290 struct backing_dev_info bdi;
296 static inline struct fuse_conn *get_fuse_conn_super(struct super_block *sb)
298 return sb->s_fs_info;
301 static inline struct fuse_conn *get_fuse_conn(struct inode *inode)
303 return get_fuse_conn_super(inode->i_sb);
306 static inline struct fuse_conn *get_fuse_conn_kobj(struct kobject *obj)
308 return container_of(obj, struct fuse_conn, kobj);
311 static inline struct fuse_inode *get_fuse_inode(struct inode *inode)
313 return container_of(inode, struct fuse_inode, inode);
316 static inline u64 get_node_id(struct inode *inode)
318 return get_fuse_inode(inode)->nodeid;
321 /** Device operations */
322 extern struct file_operations fuse_dev_operations;
325 * This is the single global spinlock which protects FUSE's structures
327 * The following data is protected by this lock:
329 * - the private_data field of the device file
330 * - the s_fs_info field of the super block
331 * - unused_list, pending, processing lists in fuse_conn
332 * - background list in fuse_conn
333 * - the unique request ID counter reqctr in fuse_conn
334 * - the sb (super_block) field in fuse_conn
335 * - the file (device file) field in fuse_conn
337 extern spinlock_t fuse_lock;
340 * Get a filled in inode
342 struct inode *fuse_iget(struct super_block *sb, unsigned long nodeid,
343 int generation, struct fuse_attr *attr);
346 * Send FORGET command
348 void fuse_send_forget(struct fuse_conn *fc, struct fuse_req *req,
349 unsigned long nodeid, u64 nlookup);
352 * Send READ or READDIR request
354 size_t fuse_send_read_common(struct fuse_req *req, struct file *file,
355 struct inode *inode, loff_t pos, size_t count,
359 * Send OPEN or OPENDIR request
361 int fuse_open_common(struct inode *inode, struct file *file, int isdir);
363 struct fuse_file *fuse_file_alloc(void);
364 void fuse_file_free(struct fuse_file *ff);
365 void fuse_finish_open(struct inode *inode, struct file *file,
366 struct fuse_file *ff, struct fuse_open_out *outarg);
369 * Send a RELEASE request
371 void fuse_send_release(struct fuse_conn *fc, struct fuse_file *ff,
372 u64 nodeid, struct inode *inode, int flags, int isdir);
375 * Send RELEASE or RELEASEDIR request
377 int fuse_release_common(struct inode *inode, struct file *file, int isdir);
380 * Send FSYNC or FSYNCDIR request
382 int fuse_fsync_common(struct file *file, struct dentry *de, int datasync,
386 * Initialize file operations on a regular file
388 void fuse_init_file_inode(struct inode *inode);
391 * Initialize inode operations on regular files and special files
393 void fuse_init_common(struct inode *inode);
396 * Initialize inode and file operations on a directory
398 void fuse_init_dir(struct inode *inode);
401 * Initialize inode operations on a symlink
403 void fuse_init_symlink(struct inode *inode);
406 * Change attributes of an inode
408 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr);
411 * Initialize the client device
413 int fuse_dev_init(void);
416 * Cleanup the client device
418 void fuse_dev_cleanup(void);
423 struct fuse_req *fuse_request_alloc(void);
428 void fuse_request_free(struct fuse_req *req);
431 * Reinitialize a request, the preallocated flag is left unmodified
433 void fuse_reset_request(struct fuse_req *req);
436 * Reserve a preallocated request
438 struct fuse_req *fuse_get_request(struct fuse_conn *fc);
441 * Decrement reference count of a request. If count goes to zero put
442 * on unused list (preallocated) or free request (not preallocated).
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);
462 * Release inodes and file associated with background request
464 void fuse_release_background(struct fuse_req *req);
467 * Get the attributes of a file
469 int fuse_do_getattr(struct inode *inode);
472 * Invalidate inode attributes
474 void fuse_invalidate_attr(struct inode *inode);
477 * Send the INIT message
479 void fuse_send_init(struct fuse_conn *fc);