fs/overlayfs/file.c

7 #include <linux/file.h>
14 #include <linux/backing-file.h>
27 static struct file *ovl_open_realfile(const struct file *file,
31 	struct inode *inode = file_inode(file);
33 	struct file *realfile;
35 	int flags = file->f_flags | OVL_OPEN_FLAGS;
51 		realfile = backing_file_open(file_user_path(file),
57 		 file, file, ovl_whatisit(inode, realinode), file->f_flags,
65 static int ovl_change_flags(struct file *file, unsigned int flags)
67 	struct inode *inode = file_inode(file);
72 	if (((flags ^ file->f_flags) & O_APPEND) && IS_APPEND(inode))
75 	if ((flags & O_DIRECT) && !(file->f_mode & FMODE_CAN_ODIRECT))
78 	if (file->f_op->check_flags) {
79 		err = file->f_op->check_flags(flags);
84 	spin_lock(&file->f_lock);
85 	file->f_flags = (file->f_flags & ~OVL_SETFL_MASK) | flags;
86 	file->f_iocb_flags = iocb_flags(file);
87 	spin_unlock(&file->f_lock);
93 	struct file *realfile;
94 	struct file *upperfile;
97 struct ovl_file *ovl_file_alloc(struct file *realfile)
116 static bool ovl_is_real_file(const struct file *realfile,
122 static struct file *ovl_real_file_path(const struct file *file,
125 	struct ovl_file *of = file->private_data;
126 	struct file *realfile = of->realfile;
134 	 * metacopied file.  We need the upperfile either way, so see if it
138 		struct file *upperfile = READ_ONCE(of->upperfile);
139 		struct file *old;
142 			upperfile = ovl_open_realfile(file, realpath);
154 		 * Stored file must be from the right inode, unless someone's
164 	if (unlikely((file->f_flags ^ realfile->f_flags) & ~OVL_OPEN_FLAGS)) {
165 		int err = ovl_change_flags(realfile, file->f_flags);
174 static struct file *ovl_real_file(const struct file *file)
176 	struct dentry *dentry = file_dentry(file);
181 		struct file *f = ovl_dir_real_file(file, false);
195 	return ovl_real_file_path(file, &realpath);
198 static int ovl_open(struct inode *inode, struct file *file)
200 	struct dentry *dentry = file_dentry(file);
201 	struct file *realfile;
211 	err = ovl_maybe_copy_up(dentry, file->f_flags);
216 	file->f_flags &= ~(O_CREAT | O_EXCL | O_NOCTTY | O_TRUNC);
222 	realfile = ovl_open_realfile(file, &realpath);
232 	file->private_data = of;
237 static int ovl_release(struct inode *inode, struct file *file)
239 	ovl_file_free(file->private_data);
243 static loff_t ovl_llseek(struct file *file, loff_t offset, int whence)
245 	struct inode *inode = file_inode(file);
246 	struct file *realfile;
256 			return file->f_pos;
259 			return vfs_setpos(file, 0, 0);
262 	realfile = ovl_real_file(file);
267 	 * Overlay file f_pos is the master copy that is preserved
271 	 * files, so we use the real file to perform seeks.
274 	realfile->f_pos = file->f_pos;
280 	file->f_pos = realfile->f_pos;
286 static void ovl_file_modified(struct file *file)
289 	ovl_copyattr(file_inode(file));
297 static void ovl_file_accessed(struct file *file)
303 	if (file->f_flags & O_NOATIME)
306 	inode = file_inode(file);
322 	touch_atime(&file->f_path);
327 	struct file *file = iocb->ki_filp;
328 	struct file *realfile;
330 		.cred = ovl_creds(file_inode(file)->i_sb),
337 	realfile = ovl_real_file(file);
347 	struct file *file = iocb->ki_filp;
348 	struct inode *inode = file_inode(file);
349 	struct file *realfile;
364 	realfile = ovl_real_file(file);
385 static ssize_t ovl_splice_read(struct file *in, loff_t *ppos,
389 	struct file *realfile;
415  * the real file.
417 static ssize_t ovl_splice_write(struct pipe_inode_info *pipe, struct file *out,
420 	struct file *realfile;
449 static int ovl_fsync(struct file *file, loff_t start, loff_t end, int datasync)
451 	struct dentry *dentry = file_dentry(file);
454 	struct file *upperfile;
458 	ret = ovl_sync_status(OVL_FS(file_inode(file)->i_sb));
462 	/* Don't sync lower file for fear of receiving EROFS error */
468 	upperfile = ovl_real_file_path(file, &upperpath);
472 	old_cred = ovl_override_creds(file_inode(file)->i_sb);
479 static int ovl_mmap(struct file *file, struct vm_area_struct *vma)
481 	struct ovl_file *of = file->private_data;
483 		.cred = ovl_creds(file_inode(file)->i_sb),
490 static long ovl_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
492 	struct inode *inode = file_inode(file);
493 	struct file *realfile;
500 	ret = file_remove_privs(file);
504 	realfile = ovl_real_file(file);
509 	old_cred = ovl_override_creds(file_inode(file)->i_sb);
514 	ovl_file_modified(file);
522 static int ovl_fadvise(struct file *file, loff_t offset, loff_t len, int advice)
524 	struct file *realfile;
528 	realfile = ovl_real_file(file);
532 	old_cred = ovl_override_creds(file_inode(file)->i_sb);
545 static loff_t ovl_copyfile(struct file *file_in, loff_t pos_in,
546 			    struct file *file_out, loff_t pos_out,
550 	struct file *realfile_in, *realfile_out;
602 static ssize_t ovl_copy_file_range(struct file *file_in, loff_t pos_in,
603 				   struct file *file_out, loff_t pos_out,
610 static loff_t ovl_remap_file_range(struct file *file_in, loff_t pos_in,
611 				   struct file *file_out, loff_t pos_out,
637 static int ovl_flush(struct file *file, fl_owner_t id)
639 	struct file *realfile;
643 	realfile = ovl_real_file(file);
648 		old_cred = ovl_override_creds(file_inode(file)->i_sb);