From patchwork Sat Apr 11 12:03:23 2009 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Eric W. Biederman" X-Patchwork-Id: 17729 Received: from vger.kernel.org (vger.kernel.org [209.132.176.167]) by demeter.kernel.org (8.14.2/8.14.2) with ESMTP id n3BC3Uhq023056 for ; Sat, 11 Apr 2009 12:03:30 GMT Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752720AbZDKMD3 (ORCPT ); Sat, 11 Apr 2009 08:03:29 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753971AbZDKMD3 (ORCPT ); Sat, 11 Apr 2009 08:03:29 -0400 Received: from out02.mta.xmission.com ([166.70.13.232]:45777 "EHLO out02.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752720AbZDKMD1 (ORCPT ); Sat, 11 Apr 2009 08:03:27 -0400 Received: from in01.mta.xmission.com ([166.70.13.51]) by out02.mta.xmission.com with esmtp (Exim 4.62) (envelope-from ) id 1Lsbvj-0005pg-3h; Sat, 11 Apr 2009 06:03:27 -0600 Received: from c-67-169-126-145.hsd1.ca.comcast.net ([67.169.126.145] helo=fess.ebiederm.org) by in01.mta.xmission.com with esmtpsa (TLSv1:AES256-SHA:256) (Exim 4.69) (envelope-from ) id 1Lsbvi-00044z-DT; Sat, 11 Apr 2009 06:03:27 -0600 Received: from fess.ebiederm.org (localhost [127.0.0.1]) by fess.ebiederm.org (8.14.3/8.14.3/Debian-4) with ESMTP id n3BC3NRu001606; Sat, 11 Apr 2009 05:03:23 -0700 Received: (from eric@localhost) by fess.ebiederm.org (8.14.3/8.14.3/Submit) id n3BC3NO1001604; Sat, 11 Apr 2009 05:03:23 -0700 X-Authentication-Warning: fess.ebiederm.org: eric set sender to ebiederm@xmission.com using -f To: Andrew Morton Cc: , , , , Al Viro , Hugh Dickins , Tejun Heo , Alexey Dobriyan , Linus Torvalds , Alan Cox , Greg Kroah-Hartman References: From: ebiederm@xmission.com (Eric W. Biederman) Date: Sat, 11 Apr 2009 05:03:23 -0700 In-Reply-To: (Eric W. Biederman's message of "Sat\, 11 Apr 2009 05\:01\:29 -0700") Message-ID: User-Agent: Gnus/5.11 (Gnus v5.11) Emacs/22.2 (gnu/linux) MIME-Version: 1.0 X-XM-SPF: eid=; ; ; mid=; ; ; hst=in01.mta.xmission.com; ; ; ip=67.169.126.145; ; ; frm=ebiederm@xmission.com; ; ; spf=neutral X-SA-Exim-Connect-IP: 67.169.126.145 X-SA-Exim-Rcpt-To: akpm@linux-foundation.org, gregkh@suse.de, alan@lxorguk.ukuu.org.uk, torvalds@linux-foundation.org, adobriyan@gmail.com, tj@kernel.org, hugh@veritas.com, viro@ZenIV.linux.org.uk, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org X-SA-Exim-Mail-From: ebiederm@xmission.com X-Spam-DCC: XMission; sa04 1397; Body=1 Fuz1=1 Fuz2=1 X-Spam-Checker-Version: SpamAssassin 3.2.5 (2008-06-10) on sa04.xmission.com X-Spam-Level: X-Spam-Status: No, score=-2.5 required=8.0 tests=ALL_TRUSTED,BAYES_00, DCC_CHECK_NEGATIVE,UNTRUSTED_Relay,XMNoVowels,XM_SPF_Neutral autolearn=disabled version=3.2.5 X-Spam-Combo: ;Andrew Morton X-Spam-Relay-Country: X-Spam-Report: * -1.8 ALL_TRUSTED Passed through trusted hosts only via SMTP * 1.5 XMNoVowels Alpha-numberic number with no vowels * -2.6 BAYES_00 BODY: Bayesian spam probability is 0 to 1% * [score: 0.0000] * -0.0 DCC_CHECK_NEGATIVE Not listed in DCC * [sa04 1397; Body=1 Fuz1=1 Fuz2=1] * 0.0 XM_SPF_Neutral SPF-Neutral * 0.4 UNTRUSTED_Relay Comes from a non-trusted relay Subject: [RFC][PATCH 1/9] mm: Introduce remap_file_mappings. X-SA-Exim-Version: 4.2.1 (built Thu, 25 Oct 2007 00:26:12 +0000) X-SA-Exim-Scanned: Yes (on in01.mta.xmission.com) Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org From 819088d701e3a821db8e08ed83d46c00c27cc772 Mon Sep 17 00:00:00 2001 From: Eric W. Biederman Date: Tue, 7 Apr 2009 19:35:07 -0700 Subject: When the backing store of a file becomes inaccessible we need a function to remove that file from the page tables and arrange for page faults to receive SIGBUS until the file is unmapped. Signed-off-by: Eric W. Biederman --- include/linux/mm.h | 1 + mm/memory.c | 87 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 88 insertions(+), 0 deletions(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index bff1f0d..96d8342 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -807,6 +807,7 @@ static inline void unmap_shared_mapping_range(struct address_space *mapping, extern int vmtruncate(struct inode * inode, loff_t offset); extern int vmtruncate_range(struct inode * inode, loff_t offset, loff_t end); +extern void remap_file_mappings(struct file *file, struct vm_operations_struct *vm_ops); #ifdef CONFIG_MMU extern int handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma, diff --git a/mm/memory.c b/mm/memory.c index cf6873e..dcd0a3c 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -2325,6 +2325,93 @@ void unmap_mapping_range(struct address_space *mapping, } EXPORT_SYMBOL(unmap_mapping_range); +static void remap_vma(struct vm_area_struct *vma, + struct vm_operations_struct *vm_ops) +{ + struct file *file = vma->vm_file; + struct address_space *mapping = file->f_mapping; + unsigned long start_addr, end_addr, size; + struct mm_struct *mm; + + start_addr = vma->vm_start; + end_addr = vma->vm_end; + + /* Has this vma already been processed? */ + if (vma->vm_ops == vm_ops) + return; + + /* Switch out the locks so I can maninuplate this under the mm sem. + * Needed so I can call vm_ops->close. + */ + mm = vma->vm_mm; + atomic_inc(&mm->mm_users); + spin_unlock(&mapping->i_mmap_lock); + + /* Block page faults and other code modifying the mm. */ + down_write(&mm->mmap_sem); + + /* Lookup a vma for my file address */ + vma = find_vma(mm, start_addr); + if (vma->vm_file != file) + goto out; + if (vma->vm_ops == vm_ops) + goto out; + + start_addr = vma->vm_start; + end_addr = vma->vm_end; + size = end_addr - start_addr; + + /* Unmap the vma */ + zap_page_range(vma, start_addr, size, NULL); + + /* Close the vma */ + if (vma->vm_ops && vma->vm_ops->close) + vma->vm_ops->close(vma); + + /* Repurpose the vma */ + vma->vm_private_data = NULL; + vma->vm_ops = vm_ops; + if (vm_ops->open) + vm_ops->open(vma); +out: + up_write(&mm->mmap_sem); + spin_lock(&mapping->i_mmap_lock); +} + +void remap_file_mappings(struct file *file, struct vm_operations_struct *vm_ops) +{ + /* After file->f_ops has been changed update the vmas */ + struct address_space *mapping = file->f_mapping; + struct vm_area_struct *vma; + struct prio_tree_iter iter; + + spin_lock(&mapping->i_mmap_lock); + +restart_tree: + vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, 0, ULONG_MAX) { + /* Skip quickly over vmas that do not need to be touched */ + if (vma->vm_file != file) + continue; + if (vma->vm_ops == vm_ops) + continue; + remap_vma(vma, vm_ops); + goto restart_tree; + } + +restart_list: + list_for_each_entry(vma, &mapping->i_mmap_nonlinear, shared.vm_set.list) { + /* Skip quickly over vmas that do not need to be touched */ + if (vma->vm_file != file) + continue; + if (vma->vm_ops == vm_ops) + continue; + remap_vma(vma, vm_ops); + goto restart_list; + } + + spin_unlock(&mapping->i_mmap_lock); +} + /** * vmtruncate - unmap mappings "freed" by truncate() syscall * @inode: inode of the file used