From: Yongqiang Yang Subject: [PATCH RFC 1/3] ext4:Add a function merging extent right and left. Date: Wed, 13 Apr 2011 22:40:49 -0700 Message-ID: <1302759651-21222-2-git-send-email-xiaoqiangnk@gmail.com> References: <1302759651-21222-1-git-send-email-xiaoqiangnk@gmail.com> Cc: achender@linux.vnet.ibm.com, cmm@us.ibm.com, Yongqiang Yang To: linux-ext4@vger.kernel.org Return-path: Received: from mail-iy0-f174.google.com ([209.85.210.174]:54504 "EHLO mail-iy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753880Ab1DNFmn (ORCPT ); Thu, 14 Apr 2011 01:42:43 -0400 Received: by mail-iy0-f174.google.com with SMTP id 14so1156431iyb.19 for ; Wed, 13 Apr 2011 22:42:43 -0700 (PDT) In-Reply-To: <1302759651-21222-1-git-send-email-xiaoqiangnk@gmail.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: 1] Rename ext4_ext_try_to_merge() to ext4_ext_try_to_merge_right(). 2] Add a new function ext4_ext_try_to_merge() which tries to merge an extent both left and right. 3] Use the new function in ext4_ext_convert_unwritten_endio() and ext4_ext_insert_extent(). Signed-off-by: Yongqiang Yang --- fs/ext4/extents.c | 65 ++++++++++++++++++++++++++++------------------------ 1 files changed, 35 insertions(+), 30 deletions(-) diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c index dd2cb50..11f30d2 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -1563,7 +1563,7 @@ ext4_can_extents_be_merged(struct inode *inode, struct ext4_extent *ex1, * Returns 0 if the extents (ex and ex+1) were _not_ merged and returns * 1 if they got merged. */ -static int ext4_ext_try_to_merge(struct inode *inode, +static int ext4_ext_try_to_merge_right(struct inode *inode, struct ext4_ext_path *path, struct ext4_extent *ex) { @@ -1603,6 +1603,31 @@ static int ext4_ext_try_to_merge(struct inode *inode, } /* + * This function tries to merge the @ex extent to neighbours in the tree. + * return 1 if merge left else 0. + */ +static int ext4_ext_try_to_merge(struct inode *inode, + struct ext4_ext_path *path, + struct ext4_extent *ex) { + struct ext4_extent_header *eh; + unsigned int depth; + int merge_done = 0; + int ret = 0; + + depth = ext_depth(inode); + BUG_ON(path[depth].p_hdr == NULL); + eh = path[depth].p_hdr; + + if (ex > EXT_FIRST_EXTENT(eh)) + merge_done = ext4_ext_try_to_merge_right(inode, path, ex - 1); + + if (!merge_done) + ret = ext4_ext_try_to_merge_right(inode, path, ex); + + return ret; +} + +/* * check if a portion of the "newext" extent overlaps with an * existing extent. * @@ -3039,6 +3064,7 @@ fix_extent_len: ext4_ext_dirty(handle, inode, path + depth); return err; } + static int ext4_convert_unwritten_extents_endio(handle_t *handle, struct inode *inode, struct ext4_ext_path *path) @@ -3047,46 +3073,25 @@ static int ext4_convert_unwritten_extents_endio(handle_t *handle, struct ext4_extent_header *eh; int depth; int err = 0; - int ret = 0; depth = ext_depth(inode); eh = path[depth].p_hdr; ex = path[depth].p_ext; + ext_debug("ext4_convert_unwritten_extents_endio: inode %lu, logical" + "block %llu, max_blocks %u\n", inode->i_ino, + (unsigned long long)le32_to_cpu(ex->ee_block), + ext4_ext_get_actual_len(ex)); + err = ext4_ext_get_access(handle, inode, path + depth); if (err) goto out; /* first mark the extent as initialized */ ext4_ext_mark_initialized(ex); - /* - * We have to see if it can be merged with the extent - * on the left. - */ - if (ex > EXT_FIRST_EXTENT(eh)) { - /* - * To merge left, pass "ex - 1" to try_to_merge(), - * since it merges towards right _only_. - */ - ret = ext4_ext_try_to_merge(inode, path, ex - 1); - if (ret) { - err = ext4_ext_correct_indexes(handle, inode, path); - if (err) - goto out; - depth = ext_depth(inode); - ex--; - } - } - /* - * Try to Merge towards right. - */ - ret = ext4_ext_try_to_merge(inode, path, ex); - if (ret) { - err = ext4_ext_correct_indexes(handle, inode, path); - if (err) - goto out; - depth = ext_depth(inode); - } + /* correct indexes is nt needed becasue borders are not changed */ + ext4_ext_try_to_merge(inode, path, ex); + /* Mark modified extent as dirty */ err = ext4_ext_dirty(handle, inode, path + depth); out: -- 1.7.4.4