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 fuse mount flags for this mount */
204 /** Readers of the connection are waiting on this */
205 wait_queue_head_t waitq;
207 /** The list of pending requests */
208 struct list_head pending;
210 /** The list of requests being processed */
211 struct list_head processing;
213 /** Requests put in the background (RELEASE or any other
214 interrupted request) */
215 struct list_head background;
217 /** Controls the maximum number of outstanding requests */
218 struct semaphore outstanding_sem;
220 /** This counts the number of outstanding requests if
221 outstanding_sem would go negative */
222 unsigned outstanding_debt;
224 /** RW semaphore for exclusion with fuse_put_super() */
225 struct rw_semaphore sbput_sem;
227 /** The list of unused requests */
228 struct list_head unused_list;
230 /** The next unique request id */
233 /** Mount is active */
234 unsigned mounted : 1;
236 /** Connection established */
237 unsigned connected : 1;
239 /** Connection failed (version mismatch) */
240 unsigned conn_error : 1;
242 /** Is fsync not implemented by fs? */
243 unsigned no_fsync : 1;
245 /** Is flush not implemented by fs? */
246 unsigned no_flush : 1;
248 /** Is setxattr not implemented by fs? */
249 unsigned no_setxattr : 1;
251 /** Is getxattr not implemented by fs? */
252 unsigned no_getxattr : 1;
254 /** Is listxattr not implemented by fs? */
255 unsigned no_listxattr : 1;
257 /** Is removexattr not implemented by fs? */
258 unsigned no_removexattr : 1;
260 /** Backing dev info */
261 struct backing_dev_info bdi;
264 struct fuse_getdir_out_i {
266 void *file; /* Used by kernel only */
269 static inline struct fuse_conn **get_fuse_conn_super_p(struct super_block *sb)
271 return (struct fuse_conn **) &sb->s_fs_info;
274 static inline struct fuse_conn *get_fuse_conn_super(struct super_block *sb)
276 return *get_fuse_conn_super_p(sb);
279 static inline struct fuse_conn *get_fuse_conn(struct inode *inode)
281 return get_fuse_conn_super(inode->i_sb);
284 static inline struct fuse_inode *get_fuse_inode(struct inode *inode)
286 return container_of(inode, struct fuse_inode, inode);
289 static inline u64 get_node_id(struct inode *inode)
291 return get_fuse_inode(inode)->nodeid;
294 /** Device operations */
295 extern struct file_operations fuse_dev_operations;
298 * This is the single global spinlock which protects FUSE's structures
300 * The following data is protected by this lock:
302 * - the private_data field of the device file
303 * - the s_fs_info field of the super block
304 * - unused_list, pending, processing lists in fuse_conn
305 * - background list in fuse_conn
306 * - the unique request ID counter reqctr in fuse_conn
307 * - the sb (super_block) field in fuse_conn
308 * - the file (device file) field in fuse_conn
310 extern spinlock_t fuse_lock;
313 * Get a filled in inode
315 struct inode *fuse_iget(struct super_block *sb, unsigned long nodeid,
316 int generation, struct fuse_attr *attr);
319 * Send FORGET command
321 void fuse_send_forget(struct fuse_conn *fc, struct fuse_req *req,
322 unsigned long nodeid, u64 nlookup);
325 * Initialise file operations on a regular file
327 void fuse_init_file_inode(struct inode *inode);
330 * Initialise inode operations on regular files and special files
332 void fuse_init_common(struct inode *inode);
335 * Initialise inode and file operations on a directory
337 void fuse_init_dir(struct inode *inode);
340 * Initialise inode operations on a symlink
342 void fuse_init_symlink(struct inode *inode);
345 * Change attributes of an inode
347 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr);
350 * Check if the connection can be released, and if yes, then free the
351 * connection structure
353 void fuse_release_conn(struct fuse_conn *fc);
356 * Initialize the client device
358 int fuse_dev_init(void);
361 * Cleanup the client device
363 void fuse_dev_cleanup(void);
368 struct fuse_req *fuse_request_alloc(void);
373 void fuse_request_free(struct fuse_req *req);
376 * Reinitialize a request, the preallocated flag is left unmodified
378 void fuse_reset_request(struct fuse_req *req);
381 * Reserve a preallocated request
383 struct fuse_req *fuse_get_request(struct fuse_conn *fc);
386 * Reserve a preallocated request, only interruptible by SIGKILL
388 struct fuse_req *fuse_get_request_nonint(struct fuse_conn *fc);
391 * Decrement reference count of a request. If count goes to zero put
392 * on unused list (preallocated) or free reqest (not preallocated).
394 void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req);
397 * Send a request (synchronous, interruptible)
399 void request_send(struct fuse_conn *fc, struct fuse_req *req);
402 * Send a request (synchronous, non-interruptible except by SIGKILL)
404 void request_send_nonint(struct fuse_conn *fc, struct fuse_req *req);
407 * Send a request with no reply
409 void request_send_noreply(struct fuse_conn *fc, struct fuse_req *req);
412 * Send a request in the background
414 void request_send_background(struct fuse_conn *fc, struct fuse_req *req);
417 * Release inodes and file assiciated with background request
419 void fuse_release_background(struct fuse_req *req);
422 * Get the attributes of a file
424 int fuse_do_getattr(struct inode *inode);
427 * Invalidate inode attributes
429 void fuse_invalidate_attr(struct inode *inode);
432 * Send the INIT message
434 void fuse_send_init(struct fuse_conn *fc);