static loff_t ovl_remap_file_range(struct file *file_in, loff_t pos_in, struct file *file_out, loff_t pos_out, loff_t len, unsigned int remap_flags) { enum ovl_copyop op; if (remap_flags & ~(REMAP_FILE_DEDUP | REMAP_FILE_ADVISORY)) return -EINVAL; if (remap_flags & REMAP_FILE_DEDUP) op = OVL_DEDUPE; else op = OVL_CLONE; /* * Don't copy up because of a dedupe request, this wouldn't make sense * most of the time (data would be duplicated instead of deduplicated). */ if (op == OVL_DEDUPE && (!ovl_inode_upper(file_inode(file_in)) || !ovl_inode_upper(file_inode(file_out)))) return -EPERM; return ovl_copyfile(file_in, pos_in, file_out, pos_out, len, remap_flags, op); }
static int ovl_dedupe_file_range(struct file *file_in, loff_t pos_in, struct file *file_out, loff_t pos_out, u64 len) { /* * Don't copy up because of a dedupe request, this wouldn't make sense * most of the time (data would be duplicated instead of deduplicated). */ if (!ovl_inode_upper(file_inode(file_in)) || !ovl_inode_upper(file_inode(file_out))) return -EPERM; return ovl_copyfile(file_in, pos_in, file_out, pos_out, len, 0, OVL_DEDUPE); }
int ovl_permission(struct inode *inode, int mask) { struct inode *upperinode = ovl_inode_upper(inode); struct inode *realinode = upperinode ?: ovl_inode_lower(inode); const struct cred *old_cred; int err; /* Careful in RCU walk mode */ if (!realinode) { WARN_ON(!(mask & MAY_NOT_BLOCK)); return -ECHILD; } /* * Check overlay inode with the creds of task and underlying inode * with creds of mounter */ err = generic_permission(inode, mask); if (err) return err; old_cred = ovl_override_creds(inode->i_sb); if (!upperinode && !special_file(realinode->i_mode) && mask & MAY_WRITE) { mask &= ~(MAY_WRITE | MAY_APPEND); /* Make sure mounter can read file for copy up later */ mask |= MAY_READ; } err = inode_permission(realinode, mask); revert_creds(old_cred); return err; }
static char ovl_whatisit(struct inode *inode, struct inode *realinode) { if (realinode != ovl_inode_upper(inode)) return 'l'; if (ovl_has_upperdata(inode)) return 'u'; else return 'm'; }
static int ovl_fsync(struct file *file, loff_t start, loff_t end, int datasync) { struct fd real; const struct cred *old_cred; int ret; ret = ovl_real_fdget_meta(file, &real, !datasync); if (ret) return ret; /* Don't sync lower file for fear of receiving EROFS error */ if (file_inode(real.file) == ovl_inode_upper(file_inode(file))) { old_cred = ovl_override_creds(file_inode(file)->i_sb); ret = vfs_fsync_range(real.file, start, end, datasync); revert_creds(old_cred); } fdput(real); return ret; }
static void ovl_file_accessed(struct file *file) { struct inode *inode, *upperinode; if (file->f_flags & O_NOATIME) return; inode = file_inode(file); upperinode = ovl_inode_upper(inode); if (!upperinode) return; if ((!timespec64_equal(&inode->i_mtime, &upperinode->i_mtime) || !timespec64_equal(&inode->i_ctime, &upperinode->i_ctime))) { inode->i_mtime = upperinode->i_mtime; inode->i_ctime = upperinode->i_ctime; } touch_atime(&file->f_path); }
static bool ovl_verify_inode(struct inode *inode, struct dentry *lowerdentry, struct dentry *upperdentry) { /* * Allow non-NULL lower inode in ovl_inode even if lowerdentry is NULL. * This happens when finding a copied up overlay inode for a renamed * or hardlinked overlay dentry and lower dentry cannot be followed * by origin because lower fs does not support file handles. */ if (lowerdentry && ovl_inode_lower(inode) != d_inode(lowerdentry)) return false; /* * Allow non-NULL __upperdentry in inode even if upperdentry is NULL. * This happens when finding a lower alias for a copied up hard link. */ if (upperdentry && ovl_inode_upper(inode) != d_inode(upperdentry)) return false; return true; }