From patchwork Fri Oct 6 22:35:49 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dan Williams X-Patchwork-Id: 9990649 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 1B1C960244 for ; Fri, 6 Oct 2017 22:42:20 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 0BC7028E14 for ; Fri, 6 Oct 2017 22:42:20 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 00D3E28E4A; Fri, 6 Oct 2017 22:42:19 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 60F4828E14 for ; Fri, 6 Oct 2017 22:42:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752909AbdJFWmR (ORCPT ); Fri, 6 Oct 2017 18:42:17 -0400 Received: from mga11.intel.com ([192.55.52.93]:34660 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751917AbdJFWmO (ORCPT ); Fri, 6 Oct 2017 18:42:14 -0400 Received: from orsmga004.jf.intel.com ([10.7.209.38]) by fmsmga102.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 06 Oct 2017 15:42:14 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.42,486,1500966000"; d="scan'208";a="136055848" Received: from dwillia2-desk3.jf.intel.com (HELO dwillia2-desk3.amr.corp.intel.com) ([10.54.39.125]) by orsmga004.jf.intel.com with ESMTP; 06 Oct 2017 15:42:13 -0700 Subject: [PATCH v7 06/12] xfs: wire up MAP_DIRECT From: Dan Williams To: linux-nvdimm@lists.01.org Cc: linux-xfs@vger.kernel.org, Jan Kara , Arnd Bergmann , "Darrick J. Wong" , linux-rdma@vger.kernel.org, linux-api@vger.kernel.org, Dave Chinner , Christoph Hellwig , "J. Bruce Fields" , linux-mm@kvack.org, Jeff Moyer , Alexander Viro , linux-fsdevel@vger.kernel.org, Jeff Layton , Ross Zwisler Date: Fri, 06 Oct 2017 15:35:49 -0700 Message-ID: <150732934955.22363.14950885120988262779.stgit@dwillia2-desk3.amr.corp.intel.com> In-Reply-To: <150732931273.22363.8436792888326501071.stgit@dwillia2-desk3.amr.corp.intel.com> References: <150732931273.22363.8436792888326501071.stgit@dwillia2-desk3.amr.corp.intel.com> User-Agent: StGit/0.17.1-9-g687f MIME-Version: 1.0 Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP MAP_DIRECT is an mmap(2) flag with the following semantics: MAP_DIRECT When specified with MAP_SHARED_VALIDATE, sets up a file lease with the same lifetime as the mapping. Unlike a typical F_RDLCK lease this lease is broken when a "lease breaker" attempts to write(2), change the block map (fallocate), or change the size of the file. Otherwise the mechanism of a lease break is identical to the typical lease break case where the lease needs to be removed (munmap) within the number of seconds specified by /proc/sys/fs/lease-break-time. If the lease holder fails to remove the lease in time the kernel will invalidate the mapping and force all future accesses to the mapping to trigger SIGBUS. In addition to lease break timeouts causing faults in the mapping to result in SIGBUS, other states of the file will trigger SIGBUS at fault time: * The file is not DAX capable * The file has reflinked (copy-on-write) blocks * The fault would trigger the filesystem to allocate blocks * The fault would trigger the filesystem to perform extent conversion In other words, MAP_DIRECT expects and enforces a fully allocated file where faults can be satisfied without modifying block map metadata. An unprivileged process may establish a MAP_DIRECT mapping on a file whose UID (owner) matches the filesystem UID of the process. A process with the CAP_LEASE capability may establish a MAP_DIRECT mapping on arbitrary files ERRORS EACCES Beyond the typical mmap(2) conditions that trigger EACCES MAP_DIRECT also requires the permission to set a file lease. EOPNOTSUPP The filesystem explicitly does not support the flag SIGBUS Attempted to write a MAP_DIRECT mapping at a file offset that might require block-map updates, or the lease timed out and the kernel invalidated the mapping. Cc: Jan Kara Cc: Arnd Bergmann Cc: Jeff Moyer Cc: Christoph Hellwig Cc: Dave Chinner Cc: Alexander Viro Cc: "Darrick J. Wong" Cc: Ross Zwisler Cc: Jeff Layton Cc: "J. Bruce Fields" Signed-off-by: Dan Williams --- fs/xfs/Kconfig | 2 - fs/xfs/xfs_file.c | 102 +++++++++++++++++++++++++++++++++++++++ include/linux/mman.h | 3 + include/uapi/asm-generic/mman.h | 1 4 files changed, 106 insertions(+), 2 deletions(-) diff --git a/fs/xfs/Kconfig b/fs/xfs/Kconfig index f62fc6629abb..f8765653a438 100644 --- a/fs/xfs/Kconfig +++ b/fs/xfs/Kconfig @@ -112,4 +112,4 @@ config XFS_ASSERT_FATAL config XFS_LAYOUT def_bool y - depends on EXPORTFS_BLOCK_OPS + depends on EXPORTFS_BLOCK_OPS || FS_DAX diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c index ebdd0bd2b261..e35518600e28 100644 --- a/fs/xfs/xfs_file.c +++ b/fs/xfs/xfs_file.c @@ -40,12 +40,22 @@ #include "xfs_iomap.h" #include "xfs_reflink.h" +#include #include #include #include +#include #include static const struct vm_operations_struct xfs_file_vm_ops; +static const struct vm_operations_struct xfs_file_vm_direct_ops; + +static inline bool +is_xfs_map_direct( + struct vm_area_struct *vma) +{ + return vma->vm_ops == &xfs_file_vm_direct_ops; +} /* * Clear the specified ranges to zero through either the pagecache or DAX. @@ -1008,6 +1018,26 @@ xfs_file_llseek( return vfs_setpos(file, offset, inode->i_sb->s_maxbytes); } +static int +xfs_vma_checks( + struct vm_area_struct *vma, + struct inode *inode) +{ + if (!is_xfs_map_direct(vma)) + return 0; + + if (!is_map_direct_valid(vma->vm_private_data)) + return VM_FAULT_SIGBUS; + + if (xfs_is_reflink_inode(XFS_I(inode))) + return VM_FAULT_SIGBUS; + + if (!IS_DAX(inode)) + return VM_FAULT_SIGBUS; + + return 0; +} + /* * Locking for serialisation of IO during page faults. This results in a lock * ordering of: @@ -1024,6 +1054,7 @@ __xfs_filemap_fault( enum page_entry_size pe_size, bool write_fault) { + struct vm_area_struct *vma = vmf->vma; struct inode *inode = file_inode(vmf->vma->vm_file); struct xfs_inode *ip = XFS_I(inode); int ret; @@ -1032,10 +1063,14 @@ __xfs_filemap_fault( if (write_fault) { sb_start_pagefault(inode->i_sb); - file_update_time(vmf->vma->vm_file); + file_update_time(vma->vm_file); } xfs_ilock(XFS_I(inode), XFS_MMAPLOCK_SHARED); + ret = xfs_vma_checks(vma, inode); + if (ret) + goto out_unlock; + if (IS_DAX(inode)) { ret = dax_iomap_fault(vmf, pe_size, &xfs_iomap_ops); } else { @@ -1044,6 +1079,8 @@ __xfs_filemap_fault( else ret = filemap_fault(vmf); } + +out_unlock: xfs_iunlock(XFS_I(inode), XFS_MMAPLOCK_SHARED); if (write_fault) @@ -1115,6 +1152,31 @@ xfs_filemap_pfn_mkwrite( } +static void +xfs_filemap_direct_open( + struct vm_area_struct *vma) +{ + get_map_direct_vma(vma->vm_private_data); +} + +static void +xfs_filemap_direct_close( + struct vm_area_struct *vma) +{ + put_map_direct_vma(vma->vm_private_data); +} + +static const struct vm_operations_struct xfs_file_vm_direct_ops = { + .fault = xfs_filemap_fault, + .huge_fault = xfs_filemap_huge_fault, + .map_pages = filemap_map_pages, + .page_mkwrite = xfs_filemap_page_mkwrite, + .pfn_mkwrite = xfs_filemap_pfn_mkwrite, + + .open = xfs_filemap_direct_open, + .close = xfs_filemap_direct_close, +}; + static const struct vm_operations_struct xfs_file_vm_ops = { .fault = xfs_filemap_fault, .huge_fault = xfs_filemap_huge_fault, @@ -1135,6 +1197,43 @@ xfs_file_mmap( return 0; } +#define XFS_MAP_SUPPORTED (LEGACY_MAP_MASK | MAP_DIRECT) + +STATIC int +xfs_file_mmap_validate( + struct file *filp, + struct vm_area_struct *vma, + unsigned long map_flags, + int fd) +{ + struct inode *inode = file_inode(filp); + struct xfs_inode *ip = XFS_I(inode); + struct map_direct_state *mds; + + if (map_flags & ~(XFS_MAP_SUPPORTED)) + return -EOPNOTSUPP; + + if ((map_flags & MAP_DIRECT) == 0) + return xfs_file_mmap(filp, vma); + + file_accessed(filp); + vma->vm_ops = &xfs_file_vm_direct_ops; + if (IS_DAX(inode)) + vma->vm_flags |= VM_MIXEDMAP | VM_HUGEPAGE; + + mds = map_direct_register(fd, vma); + if (IS_ERR(mds)) + return PTR_ERR(mds); + + /* flush in-flight faults */ + xfs_ilock(ip, XFS_MMAPLOCK_EXCL); + xfs_iunlock(ip, XFS_MMAPLOCK_EXCL); + + vma->vm_private_data = mds; + + return 0; +} + const struct file_operations xfs_file_operations = { .llseek = xfs_file_llseek, .read_iter = xfs_file_read_iter, @@ -1146,6 +1245,7 @@ const struct file_operations xfs_file_operations = { .compat_ioctl = xfs_file_compat_ioctl, #endif .mmap = xfs_file_mmap, + .mmap_validate = xfs_file_mmap_validate, .open = xfs_file_open, .release = xfs_file_release, .fsync = xfs_file_fsync, diff --git a/include/linux/mman.h b/include/linux/mman.h index 94b63b4d71ff..fab393a9dda9 100644 --- a/include/linux/mman.h +++ b/include/linux/mman.h @@ -20,6 +20,9 @@ #ifndef MAP_HUGE_1GB #define MAP_HUGE_1GB 0 #endif +#ifndef MAP_DIRECT +#define MAP_DIRECT 0 +#endif #ifndef MAP_UNINITIALIZED #define MAP_UNINITIALIZED 0 #endif diff --git a/include/uapi/asm-generic/mman.h b/include/uapi/asm-generic/mman.h index 7162cd4cca73..c916f22008e0 100644 --- a/include/uapi/asm-generic/mman.h +++ b/include/uapi/asm-generic/mman.h @@ -12,6 +12,7 @@ #define MAP_NONBLOCK 0x10000 /* do not block on IO */ #define MAP_STACK 0x20000 /* give out an address that is best suited for process/thread stacks */ #define MAP_HUGETLB 0x40000 /* create a huge page mapping */ +#define MAP_DIRECT 0x80000 /* leased block map (layout) for DAX */ /* Bits [26:31] are reserved, see mman-common.h for MAP_HUGETLB usage */