From patchwork Fri Feb 21 00:41:29 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ira Weiny X-Patchwork-Id: 1241724 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Authentication-Results: ozlabs.org; spf=none (no SPF record) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=linux-ext4-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=fail (p=none dis=none) header.from=intel.com Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 48Nt2m4dL9z9sSV for ; Fri, 21 Feb 2020 11:42:24 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729730AbgBUAmX (ORCPT ); Thu, 20 Feb 2020 19:42:23 -0500 Received: from mga04.intel.com ([192.55.52.120]:14516 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729612AbgBUAlo (ORCPT ); Thu, 20 Feb 2020 19:41:44 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by fmsmga104.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 20 Feb 2020 16:41:43 -0800 X-IronPort-AV: E=Sophos;i="5.70,466,1574150400"; d="scan'208";a="259459605" Received: from iweiny-desk2.sc.intel.com (HELO localhost) ([10.3.52.157]) by fmsmga004-auth.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 20 Feb 2020 16:41:43 -0800 From: ira.weiny@intel.com To: linux-kernel@vger.kernel.org Cc: Ira Weiny , Alexander Viro , "Darrick J. Wong" , Dan Williams , Dave Chinner , Christoph Hellwig , "Theodore Y. Ts'o" , Jan Kara , linux-ext4@vger.kernel.org, linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: [PATCH V4 08/13] fs: Prevent DAX state change if file is mmap'ed Date: Thu, 20 Feb 2020 16:41:29 -0800 Message-Id: <20200221004134.30599-9-ira.weiny@intel.com> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20200221004134.30599-1-ira.weiny@intel.com> References: <20200221004134.30599-1-ira.weiny@intel.com> MIME-Version: 1.0 Sender: linux-ext4-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org From: Ira Weiny Page faults need to ensure the inode DAX configuration is correct and consistent with the vmf information at the time of the fault. There is no easy way to ensure the vmf information is correct if a DAX change is in progress. Furthermore, there is no good use case to require changing DAX configs while the file is mmap'ed. Track mmap's of the file and fail the DAX change if the file is mmap'ed. Signed-off-by: Ira Weiny --- Changes from V2: move 'i_mapped' to struct address_space and rename mmap_count Add inode_has_mappings() helper for FS's Change reference to "mode" to "state" --- Changes from V3: Fix htmldoc error from the kbuild test robot. Reported-by: kbuild test robot Rebase cleanups --- fs/inode.c | 1 + fs/xfs/xfs_ioctl.c | 9 +++++++++ include/linux/fs.h | 7 +++++++ mm/mmap.c | 19 +++++++++++++++++-- 4 files changed, 34 insertions(+), 2 deletions(-) diff --git a/fs/inode.c b/fs/inode.c index 6e4f1cc872f2..613a045075bd 100644 --- a/fs/inode.c +++ b/fs/inode.c @@ -372,6 +372,7 @@ static void __address_space_init_once(struct address_space *mapping) INIT_LIST_HEAD(&mapping->private_list); spin_lock_init(&mapping->private_lock); mapping->i_mmap = RB_ROOT_CACHED; + atomic64_set(&mapping->mmap_count, 0); } void address_space_init_once(struct address_space *mapping) diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c index 25e12ce85075..498fae2ef9f6 100644 --- a/fs/xfs/xfs_ioctl.c +++ b/fs/xfs/xfs_ioctl.c @@ -1207,6 +1207,15 @@ xfs_ioctl_setattr_dax_invalidate( /* lock, flush and invalidate mapping in preparation for flag change */ xfs_ilock(ip, XFS_MMAPLOCK_EXCL | XFS_IOLOCK_EXCL); + + /* + * If there is a mapping in place we must remain in our current state. + */ + if (inode_has_mappings(inode)) { + error = -EBUSY; + goto out_unlock; + } + error = filemap_write_and_wait(inode->i_mapping); if (error) goto out_unlock; diff --git a/include/linux/fs.h b/include/linux/fs.h index ad0f2368031b..971fb011d0f0 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -438,6 +438,7 @@ int pagecache_write_end(struct file *, struct address_space *mapping, * @nr_thps: Number of THPs in the pagecache (non-shmem only). * @i_mmap: Tree of private and shared mappings. * @i_mmap_rwsem: Protects @i_mmap and @i_mmap_writable. + * @mmap_count: The number of times this AS has been mmap'ed * @nrpages: Number of page entries, protected by the i_pages lock. * @nrexceptional: Shadow or DAX entries, protected by the i_pages lock. * @writeback_index: Writeback starts here. @@ -459,6 +460,7 @@ struct address_space { #endif struct rb_root_cached i_mmap; struct rw_semaphore i_mmap_rwsem; + atomic64_t mmap_count; unsigned long nrpages; unsigned long nrexceptional; pgoff_t writeback_index; @@ -1939,6 +1941,11 @@ static inline void inode_aops_up_write(struct inode *inode) #define inode_aops_up_write(inode) do { (void)(inode); } while (0) #endif /* CONFIG_FS_DAX */ +static inline bool inode_has_mappings(struct inode *inode) +{ + return (atomic64_read(&inode->i_mapping->mmap_count) != 0); +} + static inline ssize_t call_read_iter(struct file *file, struct kiocb *kio, struct iov_iter *iter) { diff --git a/mm/mmap.c b/mm/mmap.c index 7cc2562b99fd..6bb16a0996b5 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -171,12 +171,17 @@ void unlink_file_vma(struct vm_area_struct *vma) static struct vm_area_struct *remove_vma(struct vm_area_struct *vma) { struct vm_area_struct *next = vma->vm_next; + struct file *f = vma->vm_file; might_sleep(); if (vma->vm_ops && vma->vm_ops->close) vma->vm_ops->close(vma); - if (vma->vm_file) - fput(vma->vm_file); + if (f) { + struct inode *inode = file_inode(f); + if (inode) + atomic64_dec(&inode->i_mapping->mmap_count); + fput(f); + } mpol_put(vma_policy(vma)); vm_area_free(vma); return next; @@ -1830,6 +1835,16 @@ unsigned long mmap_region(struct file *file, unsigned long addr, vma_set_page_prot(vma); + /* + * Track if there is mapping in place such that a state change + * does not occur on a file which is mapped + */ + if (file) { + struct inode *inode = file_inode(file); + + atomic64_inc(&inode->i_mapping->mmap_count); + } + return addr; unmap_and_free_vma: