From: Greg Harm Subject: [PATCH] Ext4: Don't normalize an falloc request if it can fit in 1 extent. Date: Fri, 28 Oct 2011 11:01:57 -0700 Message-ID: <1319824917-28345-1-git-send-email-gharm@google.com> Cc: linux-ext4@vger.kernel.org, Greg Harm To: "Theodore Ts'o" , Andreas Dilger Return-path: Received: from smtp-out.google.com ([74.125.121.67]:12991 "EHLO smtp-out.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751517Ab1J1SC3 (ORCPT ); Fri, 28 Oct 2011 14:02:29 -0400 Sender: linux-ext4-owner@vger.kernel.org List-ID: If an fallocate request fits in EXT_UNINIT_MAX_LEN, then set the EXT4_GET_BLOCKS_NO_NORMALIZE flag. For larger fallocate requests, let mballoc.c normalize the request. This fixes a problem where large requests were being split into non-contiguous extents due to haldar@google.com's "ext4: do not normalize block requests from fallocate." Testing: Checked that 8.x MB falloc'ed files are still laid down next to each other (contiguously). Checked that the maximum size extent (127.9MB) is allocated as 1 extent. Checked that a 1GB file is somewhat contiguous (often 5-6 non-contiguous extents now). Checked that a 120MB file can still be falloc'ed even if there are no single extents large enough to hold it. Signed-off-by: Greg Harm --- fs/ext4/extents.c | 13 ++++++++++--- 1 files changed, 10 insertions(+), 3 deletions(-) diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c index 57cf568..9819216 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -3761,6 +3761,7 @@ long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len) int ret2 = 0; int retries = 0; struct ext4_map_blocks map; + int map_blocks_flags; unsigned int credits, blkbits = inode->i_blkbits; /* @@ -3805,9 +3806,15 @@ retry: ret = PTR_ERR(handle); break; } - ret = ext4_map_blocks(handle, inode, &map, - EXT4_GET_BLOCKS_CREATE_UNINIT_EXT | - EXT4_GET_BLOCKS_NO_NORMALIZE); + map_blocks_flags = EXT4_GET_BLOCKS_CREATE_UNINIT_EXT; + /* + * Don't normalize the request if it can fit in one extent so + * that it doesn't get unnecessarily split into multiple + * extents. + */ + if (len <= EXT_UNINIT_MAX_LEN << blkbits) + map_blocks_flags |= EXT4_GET_BLOCKS_NO_NORMALIZE; + ret = ext4_map_blocks(handle, inode, &map, map_blocks_flags); if (ret <= 0) { #ifdef EXT4FS_DEBUG WARN_ON(ret <= 0); -- 1.7.3.1