From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id DCBF4CA9EC1 for ; Fri, 25 Oct 2019 18:11:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BB94B222C9 for ; Fri, 25 Oct 2019 18:11:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731538AbfJYSGv (ORCPT ); Fri, 25 Oct 2019 14:06:51 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:46698 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731405AbfJYSFm (ORCPT ); Fri, 25 Oct 2019 14:05:42 -0400 Received: from [167.98.27.226] (helo=deadeye) by shadbolt.decadent.org.uk with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1iO3xz-0008Ov-FF; Fri, 25 Oct 2019 19:05:39 +0100 Received: from ben by deadeye with local (Exim 4.92.2) (envelope-from ) id 1iO3xw-0001ks-Eg; Fri, 25 Oct 2019 19:05:36 +0100 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, Denis Kirjanov , "Mikko Rapeli" , "Fabian Frederick" , "Zhouyang Jia" , "Yann Droneaud" , "Sam Protsenko" , "David Howells" , "Colin Ian King" , "Linus Torvalds" , "Arnd Bergmann" , "Jan Harkes" , "Dan Carpenter" Date: Fri, 25 Oct 2019 19:03:43 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) X-Patchwork-Hint: ignore Subject: [PATCH 3.16 42/47] coda: pass the host file in vma->vm_file on mmap In-Reply-To: X-SA-Exim-Connect-IP: 167.98.27.226 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org 3.16.76-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Jan Harkes commit 7fa0a1da3dadfd9216df7745a1331fdaa0940d1c upstream. Patch series "Coda updates". The following patch series is a collection of various fixes for Coda, most of which were collected from linux-fsdevel or linux-kernel but which have as yet not found their way upstream. This patch (of 22): Various file systems expect that vma->vm_file points at their own file handle, several use file_inode(vma->vm_file) to get at their inode or use vma->vm_file->private_data. However the way Coda wrapped mmap on a host file broke this assumption, vm_file was still pointing at the Coda file and the host file systems would scribble over Coda's inode and private file data. This patch fixes the incorrect expectation and wraps vm_ops->open and vm_ops->close to allow Coda to track when the vm_area_struct is destroyed so we still release the reference on the Coda file handle at the right time. Link: http://lkml.kernel.org/r/0e850c6e59c0b147dc2dcd51a3af004c948c3697.1558117389.git.jaharkes@cs.cmu.edu Signed-off-by: Jan Harkes Cc: Arnd Bergmann Cc: Colin Ian King Cc: Dan Carpenter Cc: David Howells Cc: Fabian Frederick Cc: Mikko Rapeli Cc: Sam Protsenko Cc: Yann Droneaud Cc: Zhouyang Jia Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds [bwh: Backported to 3.16: Keep calling file_operations::mmap directly] Signed-off-by: Ben Hutchings --- fs/coda/file.c | 70 ++++++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 68 insertions(+), 2 deletions(-) --- a/fs/coda/file.c +++ b/fs/coda/file.c @@ -26,6 +26,13 @@ #include "coda_linux.h" #include "coda_int.h" +struct coda_vm_ops { + atomic_t refcnt; + struct file *coda_file; + const struct vm_operations_struct *host_vm_ops; + struct vm_operations_struct vm_ops; +}; + static ssize_t coda_file_read(struct file *coda_file, char __user *buf, size_t count, loff_t *ppos) { @@ -93,6 +100,34 @@ coda_file_write(struct file *coda_file, return ret; } +static void +coda_vm_open(struct vm_area_struct *vma) +{ + struct coda_vm_ops *cvm_ops = + container_of(vma->vm_ops, struct coda_vm_ops, vm_ops); + + atomic_inc(&cvm_ops->refcnt); + + if (cvm_ops->host_vm_ops && cvm_ops->host_vm_ops->open) + cvm_ops->host_vm_ops->open(vma); +} + +static void +coda_vm_close(struct vm_area_struct *vma) +{ + struct coda_vm_ops *cvm_ops = + container_of(vma->vm_ops, struct coda_vm_ops, vm_ops); + + if (cvm_ops->host_vm_ops && cvm_ops->host_vm_ops->close) + cvm_ops->host_vm_ops->close(vma); + + if (atomic_dec_and_test(&cvm_ops->refcnt)) { + vma->vm_ops = cvm_ops->host_vm_ops; + fput(cvm_ops->coda_file); + kfree(cvm_ops); + } +} + static int coda_file_mmap(struct file *coda_file, struct vm_area_struct *vma) { @@ -100,6 +135,8 @@ coda_file_mmap(struct file *coda_file, s struct coda_inode_info *cii; struct file *host_file; struct inode *coda_inode, *host_inode; + struct coda_vm_ops *cvm_ops; + int ret; cfi = CODA_FTOC(coda_file); BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC); @@ -108,6 +145,13 @@ coda_file_mmap(struct file *coda_file, s if (!host_file->f_op->mmap) return -ENODEV; + if (WARN_ON(coda_file != vma->vm_file)) + return -EIO; + + cvm_ops = kmalloc(sizeof(struct coda_vm_ops), GFP_KERNEL); + if (!cvm_ops) + return -ENOMEM; + coda_inode = file_inode(coda_file); host_inode = file_inode(host_file); @@ -121,6 +165,7 @@ coda_file_mmap(struct file *coda_file, s * the container file on us! */ else if (coda_inode->i_mapping != host_inode->i_mapping) { spin_unlock(&cii->c_lock); + kfree(cvm_ops); return -EBUSY; } @@ -129,7 +174,29 @@ coda_file_mmap(struct file *coda_file, s cfi->cfi_mapcount++; spin_unlock(&cii->c_lock); - return host_file->f_op->mmap(host_file, vma); + vma->vm_file = get_file(host_file); + ret = host_file->f_op->mmap(host_file, vma); + + if (ret) { + /* if ->mmap fails, our caller will put coda_file so we + * should drop the reference to the host_file that we got. + */ + fput(host_file); + kfree(cvm_ops); + } else { + /* here we add redirects for the open/close vm_operations */ + cvm_ops->host_vm_ops = vma->vm_ops; + if (vma->vm_ops) + cvm_ops->vm_ops = *vma->vm_ops; + + cvm_ops->vm_ops.open = coda_vm_open; + cvm_ops->vm_ops.close = coda_vm_close; + cvm_ops->coda_file = coda_file; + atomic_set(&cvm_ops->refcnt, 1); + + vma->vm_ops = &cvm_ops->vm_ops; + } + return ret; } int coda_open(struct inode *coda_inode, struct file *coda_file) @@ -239,4 +306,3 @@ const struct file_operations coda_file_o .fsync = coda_fsync, .splice_read = coda_file_splice_read, }; -