On Fri, Mar 25, 2011 at 09:10:05PM +0800, Yongqiang Yang wrote: > Either the first block or the last one could be not aligned with > block boundary, 1 block is needed to fix it. > > Signed-off-by: Yongqiang Yang <xiaoqiangnk@xxxxxxxxx> Thanks for the patch submission! I further modified the patch to make the commit description a bit clearer, and to fix an additional bug that I noticed while reviewing your patch. - Ted >From fa0dfea6882a833a70f04b3089a751f75c0d03f6 Mon Sep 17 00:00:00 2001 From: Yongqiang Yang <xiaoqiangnk@xxxxxxxxx> Date: Mon, 4 Apr 2011 15:38:38 -0400 Subject: [PATCH] ext4: fix credits computing for indirect mapped files When writing a contiguous set of blocks, two indirect blocks could be needed depending on how the blocks are aligned, so we need to increase the number of credits needed by one. [ Also fixed a another bug which could further underestimate the number of journal credits needed by 1; the code was using integer division instead of DIV_ROUND_UP() -- tytso] Signed-off-by: Yongqiang Yang <xiaoqiangnk@xxxxxxxxx> Signed-off-by: "Theodore Ts'o" <tytso@xxxxxxx> --- fs/ext4/inode.c | 11 +++++------ 1 files changed, 5 insertions(+), 6 deletions(-) diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 1a86282..7d11e02 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -5398,13 +5398,12 @@ static int ext4_indirect_trans_blocks(struct inode *inode, int nrblocks, /* if nrblocks are contiguous */ if (chunk) { /* - * With N contiguous data blocks, it need at most - * N/EXT4_ADDR_PER_BLOCK(inode->i_sb) indirect blocks - * 2 dindirect blocks - * 1 tindirect block + * With N contiguous data blocks, we need at most + * N/EXT4_ADDR_PER_BLOCK(inode->i_sb) + 1 indirect blocks, + * 2 dindirect blocks, and 1 tindirect block */ - indirects = nrblocks / EXT4_ADDR_PER_BLOCK(inode->i_sb); - return indirects + 3; + return DIV_ROUND_UP(nrblocks, + EXT4_ADDR_PER_BLOCK(inode->i_sb)) + 4; } /* * if nrblocks are not contiguous, worse case, each block touch -- 1.7.3.1 -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html