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 /** Maximum size of data in a write request */
25 #define FUSE_MAX_WRITE 4096
27 /** It could be as large as PATH_MAX, but would that have any uses? */
28 #define FUSE_NAME_MAX 1024
30 /** If the FUSE_DEFAULT_PERMISSIONS flag is given, the filesystem
31 module will check permissions based on the file mode. Otherwise no
32 permission checking is done in the kernel */
33 #define FUSE_DEFAULT_PERMISSIONS (1 << 0)
35 /** If the FUSE_ALLOW_OTHER flag is given, then not only the user
36 doing the mount will be allowed to access the filesystem */
37 #define FUSE_ALLOW_OTHER (1 << 1)
45 /** Unique ID, which identifies the inode between userspace
49 /** Number of lookups on this inode */
52 /** The request used for sending the FORGET message */
53 struct fuse_req *forget_req;
55 /** Time in jiffies until the file attributes are valid */
59 /** FUSE specific file data */
61 /** Request reserved for flush and release */
62 struct fuse_req *release_req;
64 /** File handle used by userspace */
68 /** One input argument of a request */
74 /** The request input */
76 /** The request header */
77 struct fuse_in_header h;
79 /** True if the data for the last argument is in req->pages */
82 /** Number of arguments */
85 /** Array of arguments */
86 struct fuse_in_arg args[3];
89 /** One output argument of a request */
95 /** The request output */
97 /** Header returned from userspace */
98 struct fuse_out_header h;
100 /** Last argument is variable length (can be shorter than
104 /** Last argument is a list of pages to copy data to */
107 /** Zero partially or not copied pages */
108 unsigned page_zeroing:1;
110 /** Number or arguments */
113 /** Array of arguments */
114 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 /** Maximum write size */
213 /** Readers of the connection are waiting on this */
214 wait_queue_head_t waitq;
216 /** The list of pending requests */
217 struct list_head pending;
219 /** The list of requests being processed */
220 struct list_head processing;
222 /** Requests put in the background (RELEASE or any other
223 interrupted request) */
224 struct list_head background;
226 /** Controls the maximum number of outstanding requests */
227 struct semaphore outstanding_sem;
229 /** This counts the number of outstanding requests if
230 outstanding_sem would go negative */
231 unsigned outstanding_debt;
233 /** RW semaphore for exclusion with fuse_put_super() */
234 struct rw_semaphore sbput_sem;
236 /** The list of unused requests */
237 struct list_head unused_list;
239 /** The next unique request id */
242 /** Mount is active */
243 unsigned mounted : 1;
245 /** Connection established */
246 unsigned connected : 1;
248 /** Connection failed (version mismatch) */
249 unsigned conn_error : 1;
251 /** Is fsync not implemented by fs? */
252 unsigned no_fsync : 1;
254 /** Is fsyncdir not implemented by fs? */
255 unsigned no_fsyncdir : 1;
257 /** Is flush not implemented by fs? */
258 unsigned no_flush : 1;
260 /** Is setxattr not implemented by fs? */
261 unsigned no_setxattr : 1;
263 /** Is getxattr not implemented by fs? */
264 unsigned no_getxattr : 1;
266 /** Is listxattr not implemented by fs? */
267 unsigned no_listxattr : 1;
269 /** Is removexattr not implemented by fs? */
270 unsigned no_removexattr : 1;
272 /** Is access not implemented by fs? */
273 unsigned no_access : 1;
275 /** Is create not implemented by fs? */
276 unsigned no_create : 1;
278 /** Negotiated minor version */
281 /** Backing dev info */
282 struct backing_dev_info bdi;
285 static inline struct fuse_conn **get_fuse_conn_super_p(struct super_block *sb)
287 return (struct fuse_conn **) &sb->s_fs_info;
290 static inline struct fuse_conn *get_fuse_conn_super(struct super_block *sb)
292 return *get_fuse_conn_super_p(sb);
295 static inline struct fuse_conn *get_fuse_conn(struct inode *inode)
297 return get_fuse_conn_super(inode->i_sb);
300 static inline struct fuse_inode *get_fuse_inode(struct inode *inode)
302 return container_of(inode, struct fuse_inode, inode);
305 static inline u64 get_node_id(struct inode *inode)
307 return get_fuse_inode(inode)->nodeid;
310 /** Device operations */
311 extern struct file_operations fuse_dev_operations;
314 * This is the single global spinlock which protects FUSE's structures
316 * The following data is protected by this lock:
318 * - the private_data field of the device file
319 * - the s_fs_info field of the super block
320 * - unused_list, pending, processing lists in fuse_conn
321 * - background list in fuse_conn
322 * - the unique request ID counter reqctr in fuse_conn
323 * - the sb (super_block) field in fuse_conn
324 * - the file (device file) field in fuse_conn
326 extern spinlock_t fuse_lock;
329 * Get a filled in inode
331 struct inode *fuse_iget(struct super_block *sb, unsigned long nodeid,
332 int generation, struct fuse_attr *attr);
335 * Send FORGET command
337 void fuse_send_forget(struct fuse_conn *fc, struct fuse_req *req,
338 unsigned long nodeid, u64 nlookup);
341 * Send READ or READDIR request
343 size_t fuse_send_read_common(struct fuse_req *req, struct file *file,
344 struct inode *inode, loff_t pos, size_t count,
348 * Send OPEN or OPENDIR request
350 int fuse_open_common(struct inode *inode, struct file *file, int isdir);
352 struct fuse_file *fuse_file_alloc(void);
353 void fuse_file_free(struct fuse_file *ff);
354 void fuse_finish_open(struct inode *inode, struct file *file,
355 struct fuse_file *ff, struct fuse_open_out *outarg);
358 * Send a RELEASE request
360 void fuse_send_release(struct fuse_conn *fc, struct fuse_file *ff,
361 u64 nodeid, struct inode *inode, int flags, int isdir);
364 * Send RELEASE or RELEASEDIR request
366 int fuse_release_common(struct inode *inode, struct file *file, int isdir);
369 * Send FSYNC or FSYNCDIR request
371 int fuse_fsync_common(struct file *file, struct dentry *de, int datasync,
375 * Initialize file operations on a regular file
377 void fuse_init_file_inode(struct inode *inode);
380 * Initialize inode operations on regular files and special files
382 void fuse_init_common(struct inode *inode);
385 * Initialize inode and file operations on a directory
387 void fuse_init_dir(struct inode *inode);
390 * Initialize inode operations on a symlink
392 void fuse_init_symlink(struct inode *inode);
395 * Change attributes of an inode
397 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr);
400 * Check if the connection can be released, and if yes, then free the
401 * connection structure
403 void fuse_release_conn(struct fuse_conn *fc);
406 * Initialize the client device
408 int fuse_dev_init(void);
411 * Cleanup the client device
413 void fuse_dev_cleanup(void);
418 struct fuse_req *fuse_request_alloc(void);
423 void fuse_request_free(struct fuse_req *req);
426 * Reinitialize a request, the preallocated flag is left unmodified
428 void fuse_reset_request(struct fuse_req *req);
431 * Reserve a preallocated request
433 struct fuse_req *fuse_get_request(struct fuse_conn *fc);
436 * Decrement reference count of a request. If count goes to zero put
437 * on unused list (preallocated) or free request (not preallocated).
439 void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req);
442 * Send a request (synchronous)
444 void request_send(struct fuse_conn *fc, struct fuse_req *req);
447 * Send a request with no reply
449 void request_send_noreply(struct fuse_conn *fc, struct fuse_req *req);
452 * Send a request in the background
454 void request_send_background(struct fuse_conn *fc, struct fuse_req *req);
457 * Release inodes and file associated with background request
459 void fuse_release_background(struct fuse_req *req);
462 * Get the attributes of a file
464 int fuse_do_getattr(struct inode *inode);
467 * Invalidate inode attributes
469 void fuse_invalidate_attr(struct inode *inode);
472 * Send the INIT message
474 void fuse_send_init(struct fuse_conn *fc);