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 /** If the FUSE_DEFAULT_PERMISSIONS flag is given, the filesystem
25 module will check permissions based on the file mode. Otherwise no
26 permission checking is done in the kernel */
27 #define FUSE_DEFAULT_PERMISSIONS (1 << 0)
29 /** If the FUSE_ALLOW_OTHER flag is given, then not only the user
30 doing the mount will be allowed to access the filesystem */
31 #define FUSE_ALLOW_OTHER (1 << 1)
33 /** If the FUSE_KERNEL_CACHE flag is given, then cached data will not
35 #define FUSE_KERNEL_CACHE (1 << 2)
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];
118 * A request to the client
121 /** This can be on either unused_list, pending or processing
122 lists in fuse_conn */
123 struct list_head list;
125 /** Entry on the background list */
126 struct list_head bg_entry;
131 /** True if the request has reply */
134 /** The request is preallocated */
135 unsigned preallocated:1;
137 /** The request was interrupted */
138 unsigned interrupted:1;
140 /** Request is sent in the background */
141 unsigned background:1;
143 /** Data is being copied to/from the request */
146 /** Request has been sent to userspace */
149 /** The request is finished */
152 /** The request input */
155 /** The request output */
158 /** Used to wake up the task waiting for completion of request*/
159 wait_queue_head_t waitq;
161 /** Data for asynchronous requests */
163 struct fuse_forget_in forget_in;
164 struct fuse_release_in release_in;
165 struct fuse_init_in_out init_in_out;
169 struct page *pages[FUSE_MAX_PAGES_PER_REQ];
171 /** number of pages in vector */
174 /** offset of data on first page */
175 unsigned page_offset;
177 /** Inode used in the request */
180 /** Second inode used in the request (or NULL) */
181 struct inode *inode2;
183 /** File used in the request (or NULL) */
190 * This structure is created, when the filesystem is mounted, and is
191 * destroyed, when the client device is closed and the filesystem is
195 /** Reference count */
198 /** The user id for this mount */
201 /** The group id for this mount */
204 /** The fuse mount flags for this mount */
207 /** Maximum read size */
210 /** Readers of the connection are waiting on this */
211 wait_queue_head_t waitq;
213 /** The list of pending requests */
214 struct list_head pending;
216 /** The list of requests being processed */
217 struct list_head processing;
219 /** Requests put in the background (RELEASE or any other
220 interrupted request) */
221 struct list_head background;
223 /** Controls the maximum number of outstanding requests */
224 struct semaphore outstanding_sem;
226 /** This counts the number of outstanding requests if
227 outstanding_sem would go negative */
228 unsigned outstanding_debt;
230 /** RW semaphore for exclusion with fuse_put_super() */
231 struct rw_semaphore sbput_sem;
233 /** The list of unused requests */
234 struct list_head unused_list;
236 /** The next unique request id */
239 /** Mount is active */
240 unsigned mounted : 1;
242 /** Connection established */
243 unsigned connected : 1;
245 /** Connection failed (version mismatch) */
246 unsigned conn_error : 1;
248 /** Is fsync not implemented by fs? */
249 unsigned no_fsync : 1;
251 /** Is flush not implemented by fs? */
252 unsigned no_flush : 1;
254 /** Is setxattr not implemented by fs? */
255 unsigned no_setxattr : 1;
257 /** Is getxattr not implemented by fs? */
258 unsigned no_getxattr : 1;
260 /** Is listxattr not implemented by fs? */
261 unsigned no_listxattr : 1;
263 /** Is removexattr not implemented by fs? */
264 unsigned no_removexattr : 1;
266 /** Backing dev info */
267 struct backing_dev_info bdi;
270 struct fuse_getdir_out_i {
272 void *file; /* Used by kernel only */
275 static inline struct fuse_conn **get_fuse_conn_super_p(struct super_block *sb)
277 return (struct fuse_conn **) &sb->s_fs_info;
280 static inline struct fuse_conn *get_fuse_conn_super(struct super_block *sb)
282 return *get_fuse_conn_super_p(sb);
285 static inline struct fuse_conn *get_fuse_conn(struct inode *inode)
287 return get_fuse_conn_super(inode->i_sb);
290 static inline struct fuse_inode *get_fuse_inode(struct inode *inode)
292 return container_of(inode, struct fuse_inode, inode);
295 static inline u64 get_node_id(struct inode *inode)
297 return get_fuse_inode(inode)->nodeid;
300 /** Device operations */
301 extern struct file_operations fuse_dev_operations;
304 * This is the single global spinlock which protects FUSE's structures
306 * The following data is protected by this lock:
308 * - the private_data field of the device file
309 * - the s_fs_info field of the super block
310 * - unused_list, pending, processing lists in fuse_conn
311 * - background list in fuse_conn
312 * - the unique request ID counter reqctr in fuse_conn
313 * - the sb (super_block) field in fuse_conn
314 * - the file (device file) field in fuse_conn
316 extern spinlock_t fuse_lock;
319 * Get a filled in inode
321 struct inode *fuse_iget(struct super_block *sb, unsigned long nodeid,
322 int generation, struct fuse_attr *attr);
325 * Send FORGET command
327 void fuse_send_forget(struct fuse_conn *fc, struct fuse_req *req,
328 unsigned long nodeid, u64 nlookup);
331 * Initialise file operations on a regular file
333 void fuse_init_file_inode(struct inode *inode);
336 * Initialise inode operations on regular files and special files
338 void fuse_init_common(struct inode *inode);
341 * Initialise inode and file operations on a directory
343 void fuse_init_dir(struct inode *inode);
346 * Initialise inode operations on a symlink
348 void fuse_init_symlink(struct inode *inode);
351 * Change attributes of an inode
353 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr);
356 * Check if the connection can be released, and if yes, then free the
357 * connection structure
359 void fuse_release_conn(struct fuse_conn *fc);
362 * Initialize the client device
364 int fuse_dev_init(void);
367 * Cleanup the client device
369 void fuse_dev_cleanup(void);
374 struct fuse_req *fuse_request_alloc(void);
379 void fuse_request_free(struct fuse_req *req);
382 * Reinitialize a request, the preallocated flag is left unmodified
384 void fuse_reset_request(struct fuse_req *req);
387 * Reserve a preallocated request
389 struct fuse_req *fuse_get_request(struct fuse_conn *fc);
392 * Reserve a preallocated request, only interruptible by SIGKILL
394 struct fuse_req *fuse_get_request_nonint(struct fuse_conn *fc);
397 * Decrement reference count of a request. If count goes to zero put
398 * on unused list (preallocated) or free reqest (not preallocated).
400 void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req);
403 * Send a request (synchronous, interruptible)
405 void request_send(struct fuse_conn *fc, struct fuse_req *req);
408 * Send a request (synchronous, non-interruptible except by SIGKILL)
410 void request_send_nonint(struct fuse_conn *fc, struct fuse_req *req);
413 * Send a request with no reply
415 void request_send_noreply(struct fuse_conn *fc, struct fuse_req *req);
418 * Send a request in the background
420 void request_send_background(struct fuse_conn *fc, struct fuse_req *req);
423 * Release inodes and file assiciated with background request
425 void fuse_release_background(struct fuse_req *req);
428 * Get the attributes of a file
430 int fuse_do_getattr(struct inode *inode);
433 * Invalidate inode attributes
435 void fuse_invalidate_attr(struct inode *inode);
438 * Send the INIT message
440 void fuse_send_init(struct fuse_conn *fc);