linux-kernel - [PATCH v3 5/5] ext4: Defer mmap cmtime update until writeback

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Message-Id: <d59d6c9790bd3c36b93343ed91be5e0cda7e5f09.1376679411.git.luto@amacapital.net>
Date:	Fri, 16 Aug 2013 16:22:12 -0700
From:	Andy Lutomirski <luto@...capital.net>
To:	linux-kernel@...r.kernel.org
Cc:	linux-ext4@...r.kernel.org, Dave Chinner <david@...morbit.com>,
	Theodore Ts'o <tytso@....edu>,
	Dave Hansen <dave.hansen@...ux.intel.com>, xfs@....sgi.com,
	Jan Kara <jack@...e.cz>, Tim Chen <tim.c.chen@...ux.intel.com>,
	Christoph Hellwig <hch@...radead.org>,
	Andy Lutomirski <luto@...capital.net>
Subject: [PATCH v3 5/5] ext4: Defer mmap cmtime update until writeback

A fancier implementation could probably avoid an extra journal
transaction by adding a mapping_test_clear_cmtime call in
ext4_writepages, but this should already be a considerable
improvement -- we'll start one transaction per writepages call
instead of one per page.

Signed-off-by: Andy Lutomirski <luto@...capital.net>
---
 fs/ext4/inode.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index dd32a2e..cee6b45 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -3236,6 +3236,7 @@ static const struct address_space_operations ext4_aops = {
 	.readpages		= ext4_readpages,
 	.writepage		= ext4_writepage,
 	.writepages		= ext4_writepages,
+	.flush_cmtime		= generic_flush_cmtime,
 	.write_begin		= ext4_write_begin,
 	.write_end		= ext4_write_end,
 	.bmap			= ext4_bmap,
@@ -3252,6 +3253,7 @@ static const struct address_space_operations ext4_journalled_aops = {
 	.readpages		= ext4_readpages,
 	.writepage		= ext4_writepage,
 	.writepages		= ext4_writepages,
+	.flush_cmtime		= generic_flush_cmtime,
 	.write_begin		= ext4_write_begin,
 	.write_end		= ext4_journalled_write_end,
 	.set_page_dirty		= ext4_journalled_set_page_dirty,
@@ -3268,6 +3270,7 @@ static const struct address_space_operations ext4_da_aops = {
 	.readpages		= ext4_readpages,
 	.writepage		= ext4_writepage,
 	.writepages		= ext4_writepages,
+	.flush_cmtime		= generic_flush_cmtime,
 	.write_begin		= ext4_da_write_begin,
 	.write_end		= ext4_da_write_end,
 	.bmap			= ext4_bmap,
@@ -5025,7 +5028,6 @@ int ext4_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
 	int retries = 0;
 
 	sb_start_pagefault(inode->i_sb);
-	file_update_time(vma->vm_file);
 	/* Delalloc case is easy... */
 	if (test_opt(inode->i_sb, DELALLOC) &&
 	    !ext4_should_journal_data(inode) &&
-- 
1.8.3.1

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