+static loff_t fuse_lseek(struct file *file, loff_t offset, int whence)
+{
+ struct inode *inode = file->f_mapping->host;
+ struct fuse_conn *fc = get_fuse_conn(inode);
+ struct fuse_file *ff = file->private_data;
+ FUSE_ARGS(args);
+ struct fuse_lseek_in inarg = {
+ .fh = ff->fh,
+ .offset = offset,
+ .whence = whence
+ };
+ struct fuse_lseek_out outarg;
+ int err;
+
+ if (fc->no_lseek)
+ goto fallback;
+
+ args.in.h.opcode = FUSE_LSEEK;
+ args.in.h.nodeid = ff->nodeid;
+ args.in.numargs = 1;
+ args.in.args[0].size = sizeof(inarg);
+ args.in.args[0].value = &inarg;
+ args.out.numargs = 1;
+ args.out.args[0].size = sizeof(outarg);
+ args.out.args[0].value = &outarg;
+ err = fuse_simple_request(fc, &args);
+ if (err) {
+ if (err == -ENOSYS) {
+ fc->no_lseek = 1;
+ goto fallback;
+ }
+ return err;
+ }
+
+ return vfs_setpos(file, outarg.offset, inode->i_sb->s_maxbytes);
+
+fallback:
+ err = fuse_update_attributes(inode, NULL, file, NULL);
+ if (!err)
+ return generic_file_llseek(file, offset, whence);
+ else
+ return err;
+}
+