10 #include <linux/file.h>
40 /* SLAB cache for file structures */
47 	struct file *f = container_of(head, struct file, f_u.fu_rcuhead);  in file_free_rcu()
53 static inline void file_free(struct file *f)  in file_free()
95 /* Find an unused file structure and return a pointer to it.
96  * Returns NULL, if there are no more free file structures or
105 struct file *get_empty_filp(void)  in get_empty_filp()
109 	struct file * f;  in get_empty_filp()
143 		pr_info("VFS: file-max limit %lu reached\n", get_max_files());  in get_empty_filp()
155  * alloc_file - allocate and initialize a 'struct file'
156  * @mnt: the vfsmount on which the file will reside
157  * @dentry: the dentry representing the new file
158  * @mode: the mode with which the new file will be opened
159  * @fop: the 'struct file_operations' for the new file
162  * 'struct file'.  Do so because of the same initialization
169 struct file *alloc_file(struct path *path, fmode_t mode,  in alloc_file()
172 	struct file *file;  in alloc_file()  local
174 	file = get_empty_filp();  in alloc_file()
175 	if (!file)  in alloc_file()
178 	file->f_path = *path;  in alloc_file()
179 	file->f_mapping = path->dentry->d_inode->i_mapping;  in alloc_file()
180 	file->f_mode = mode;  in alloc_file()
181 	file->f_op = fop;  in alloc_file()
190 		file_take_write(file);  in alloc_file()
195 	return file;  in alloc_file()
200  * drop_file_write_access - give up ability to write to a file
201  * @file: the file to which we will stop writing
204  * to write to @file, along with access to write through
207 void drop_file_write_access(struct file *file)  in drop_file_write_access()  argument
209 	struct vfsmount *mnt = file->f_path.mnt;  in drop_file_write_access()
210 	struct dentry *dentry = file->f_path.dentry;  in drop_file_write_access()
217 	if (file_check_writeable(file) != 0)  in drop_file_write_access()
220 	file_release_write(file);  in drop_file_write_access()
224 /* the real guts of fput() - releasing the last reference to file
226 static void __fput(struct file *file)  in __fput()  argument
228 	struct dentry *dentry = file->f_path.dentry;  in __fput()
229 	struct vfsmount *mnt = file->f_path.mnt;  in __fput()
234 	fsnotify_close(file);  in __fput()
237 	 * in the file cleanup chain.  in __fput()
239 	eventpoll_release(file);  in __fput()
240 	locks_remove_flock(file);  in __fput()
242 	if (unlikely(file->f_flags & FASYNC)) {  in __fput()
243 		if (file->f_op && file->f_op->fasync)  in __fput()
244 			file->f_op->fasync(-1, file, 0);  in __fput()
246 	if (file->f_op && file->f_op->release)  in __fput()
247 		file->f_op->release(inode, file);  in __fput()
248 	security_file_free(file);  in __fput()
249 	ima_file_free(file);  in __fput()
251 		     !(file->f_mode & FMODE_PATH))) {  in __fput()
254 	fops_put(file->f_op);  in __fput()
255 	put_pid(file->f_owner.pid);  in __fput()
256 	file_sb_list_del(file);  in __fput()
257 	if ((file->f_mode & (FMODE_READ | FMODE_WRITE)) == FMODE_READ)  in __fput()
259 	if (file->f_mode & FMODE_WRITE)  in __fput()
260 		drop_file_write_access(file);  in __fput()
261 	file->f_path.dentry = NULL;  in __fput()
262 	file->f_path.mnt = NULL;  in __fput()
263 	file_free(file);  in __fput()
268 void fput(struct file *file)  in fput()  argument
270 	if (atomic_long_dec_and_test(&file->f_count))  in fput()
271 		__fput(file);  in fput()
276 struct file *fget(unsigned int fd)  in fget()
278 	struct file *file;  in fget()  local
282 	file = fcheck_files(files, fd);  in fget()
283 	if (file) {  in fget()
284 		/* File object ref couldn't be taken */  in fget()
285 		if (file->f_mode & FMODE_PATH ||  in fget()
286 		    !atomic_long_inc_not_zero(&file->f_count))  in fget()
287 			file = NULL;  in fget()
291 	return file;  in fget()
296 struct file *fget_raw(unsigned int fd)  in fget_raw()
298 	struct file *file;  in fget_raw()  local
302 	file = fcheck_files(files, fd);  in fget_raw()
303 	if (file) {  in fget_raw()
304 		/* File object ref couldn't be taken */  in fget_raw()
305 		if (!atomic_long_inc_not_zero(&file->f_count))  in fget_raw()
306 			file = NULL;  in fget_raw()
310 	return file;  in fget_raw()
316  * Lightweight file lookup - no refcnt increment if fd table isn't shared.
321  *    to userspace (i.e. you cannot remember the returned struct file * after
323  * 2) You must not call filp_close on the returned struct file * in between
331 struct file *fget_light(unsigned int fd, int *fput_needed)  in fget_light()
333 	struct file *file;  in fget_light()  local
338 		file = fcheck_files(files, fd);  in fget_light()
339 		if (file && (file->f_mode & FMODE_PATH))  in fget_light()
340 			file = NULL;  in fget_light()
343 		file = fcheck_files(files, fd);  in fget_light()
344 		if (file) {  in fget_light()
345 			if (!(file->f_mode & FMODE_PATH) &&  in fget_light()
346 			    atomic_long_inc_not_zero(&file->f_count))  in fget_light()
350 				file = NULL;  in fget_light()
355 	return file;  in fget_light()
358 struct file *fget_raw_light(unsigned int fd, int *fput_needed)  in fget_raw_light()
360 	struct file *file;  in fget_raw_light()  local
365 		file = fcheck_files(files, fd);  in fget_raw_light()
368 		file = fcheck_files(files, fd);  in fget_raw_light()
369 		if (file) {  in fget_raw_light()
370 			if (atomic_long_inc_not_zero(&file->f_count))  in fget_raw_light()
374 				file = NULL;  in fget_raw_light()
379 	return file;  in fget_raw_light()
382 void put_filp(struct file *file)  in put_filp()  argument
384 	if (atomic_long_dec_and_test(&file->f_count)) {  in put_filp()
385 		security_file_free(file);  in put_filp()
386 		file_sb_list_del(file);  in put_filp()
387 		file_free(file);  in put_filp()
391 static inline int file_list_cpu(struct file *file)  in file_list_cpu()  argument
394 	return file->f_sb_list_cpu;  in file_list_cpu()
401 static inline void __file_sb_list_add(struct file *file, struct super_block *sb)  in __file_sb_list_add()  argument
407 	file->f_sb_list_cpu = cpu;  in __file_sb_list_add()
412 	list_add(&file->f_u.fu_list, list);  in __file_sb_list_add()
416  * file_sb_list_add - add a file to the sb's file list
417  * @file: file to add
420  * Use this function to associate a file with the superblock of the inode it
423 void file_sb_list_add(struct file *file, struct super_block *sb)  in file_sb_list_add()  argument
426 	__file_sb_list_add(file, sb);  in file_sb_list_add()
431  * file_sb_list_del - remove a file from the sb's file list
432  * @file: file to remove
435  * Use this function to remove a file from its superblock.
437 void file_sb_list_del(struct file *file)  in file_sb_list_del()  argument
439 	if (!list_empty(&file->f_u.fu_list)) {  in file_sb_list_del()
440 		lg_local_lock_cpu(files_lglock, file_list_cpu(file));  in file_sb_list_del()
441 		list_del_init(&file->f_u.fu_list);  in file_sb_list_del()
442 		lg_local_unlock_cpu(files_lglock, file_list_cpu(file));  in file_sb_list_del()
486 	struct file *f;  in mark_files_ro()
518 	filp_cachep = kmem_cache_create("filp", sizeof(struct file), 0,  in files_init()
522 	 * One file with associated inode and dcache is very roughly 1K.  in files_init()