| From | Paul Gortmaker <> | Subject | [34-longterm 052/196] ext4: fix credits computing for indirect mapped files | Date | Mon, 12 Mar 2012 20:19:25 -0400 |
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From: Yongqiang Yang <xiaoqiangnk@gmail.com>
------------------- This is a commit scheduled for the next v2.6.34 longterm release. If you see a problem with using this for longterm, please comment. -------------------
commit 5b41395fcc0265fc9f193aef9df39ce49d64677c upstream.
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@gmail.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> --- fs/ext4/inode.c | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-)
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 4eced51..904f3e4 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -5573,13 +5573,12 @@ 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 -- 1.7.9.3
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