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Message-ID: <CAKYAXd-zdfcJusQX3sBxfANztnmzprp+RtEchCX0_twHq_291w@mail.gmail.com>
Date: Fri, 22 Jul 2022 15:32:36 +0900
From: Namjae Jeon <linkinjeon@...nel.org>
To: "Yuezhang.Mo@...y.com" <Yuezhang.Mo@...y.com>
Cc: "sj1557.seo" <sj1557.seo@...sung.com>,
linux-fsdevel <linux-fsdevel@...r.kernel.org>,
linux-kernel <linux-kernel@...r.kernel.org>,
"Andy.Wu@...y.com" <Andy.Wu@...y.com>,
"Wataru.Aoyama@...y.com" <Wataru.Aoyama@...y.com>
Subject: Re: [PATCH v2 0/3] exfat: remove duplicate write directory entries
2022-07-11 18:29 GMT+09:00, Yuezhang.Mo@...y.com <Yuezhang.Mo@...y.com>:
> Changes for v2:
> - [1/3]: Fix timing of calling __exfat_write_inode()
> - __exfat_write_inode() should be called after updating inode.
> - This call will be removed in [3/3], so the patch series is
> no code changes between v1 and v2.
>
>
> These patches simplifie the code, and removes unnecessary writes for the
> following operations.
>
> 1. Write data to an empty file
> * Preparation
> ```
> mkdir /mnt/dir;touch /mnt/dir/file;sync
> ```
> * Capture the blktrace log of the following command
> ```
> dd if=/dev/zero of=/mnt/dir/file bs=${cluster_size} count=1 oflag=append
> conv=notrunc
> ```
> * blktrace log
> * Before
> ```
> 179,3 0 1 0.000000000 84 C WS 2623488 + 1 [0]
> BootArea
> 179,3 2 1 30.259435003 189 C W 2628864 + 256 [0]
> /dir/file
> 179,3 0 2 30.264066003 84 C W 2627584 + 1 [0]
> BitMap
> 179,3 2 2 30.261749337 189 C W 2628608 + 1 [0]
> /dir/
> 179,3 0 3 60.479159007 84 C W 2628608 + 1 [0]
> /dir/
> ```
> * After
> ```
> 179,3 0 1 0.000000000 84 C WS 2623488 + 1 [0]
> BootArea
> 179,3 3 1 30.185383337 87 C W 2629888 + 256 [0]
> /dir/file
> 179,3 0 2 30.246422004 84 C W 2627584 + 1 [0]
> BitMap
> 179,3 0 3 60.466497674 84 C W 2628352 + 1 [0]
> /dir/
> ```
>
> 2. Allocate a new cluster for a directory
> * Preparation
> ```
> mkdir /mnt/dir
> for ((i=1; i<cluster_size/96; i++)); do > /mnt/dir/file$i; done
> mkdir /mnt/dir/dir1; sync
> ```
> * Capture the blktrace log of the following command
> ```
> > /mnt/dir/file
> ```
> * blktrace log
> - Before
> ```
> 179,3 0 1 0.000000000 84 C WS 2623488 + 1 [0]
> BootArea
> 179,3 2 1 30.263762003 189 C W 2629504 + 128 [0]
> /dir/
> 179,3 2 2 30.275596670 189 C W 2629376 + 128 [0]
> /dir/
> 179,3 2 3 30.290174003 189 C W 2629119 + 1 [0]
> /dir/
> 179,3 2 4 30.292362670 189 C W 2628096 + 1 [0]
> /
> 179,3 2 5 30.294547337 189 C W 2627584 + 1 [0]
> BitMap
> 179,3 0 2 30.296661337 84 C W 2625536 + 1 [0]
> FatArea
> 179,3 0 3 60.478775007 84 C W 2628096 + 1 [0]
> /
> ```
> - After
> ```
> 179,3 0 1 0.000000000 84 C WS 2623488 + 1 [0]
> BootArea
> 179,3 3 1 30.288114670 87 C W 2631552 + 128 [0]
> /dir/
> 179,3 3 2 30.303518003 87 C W 2631424 + 128 [0]
> /dir/
> 179,3 3 3 30.324212337 87 C W 2631167 + 1 [0]
> /dir/
> 179,3 3 4 30.326579003 87 C W 2627584 + 1 [0]
> BitMap
> 179,3 0 2 30.328892670 84 C W 2625536 + 1 [0]
> FatArea
> 179,3 0 3 60.503128674 84 C W 2628096 + 1 [0]
> /
> ```
>
> 3. Truncate and release cluster from the file
> * Preparation
> ```
> mkdir /mnt/dir
> dd if=/dev/zero of=/mnt/dir/file bs=${cluster_size} count=2
> sync
> ```
> * Capture the blktrace log of the following command
> ```
> truncate -s ${cluster_size} /mnt/dir/file
> ```
>
> * blktrace log
> * Before
> ```
> 179,3 0 1 0.000000000 84 C WS 2623488 + 1 [0]
> BootArea
> 179,3 1 1 5.048452334 49 C W 2629120 + 1 [0]
> /dir/
> 179,3 0 2 5.062994334 84 C W 2627584 + 1 [0]
> BitMap
> 179,3 0 3 10.031253002 84 C W 2629120 + 1 [0]
> /dir/
> ```
>
> * After
> ```
> 179,3 0 1 0.000000000 9143 C WS 2623488 + 1 [0]
> BootArea
> 179,3 0 2 14.839244001 9143 C W 2629888 + 1 [0]
> /dir/
> 179,3 0 3 14.841562335 9143 C W 2627584 + 1 [0]
> BitMap
> ```
>
> Yuezhang Mo (3):
> exfat: reuse __exfat_write_inode() to update directory entry
> exfat: remove duplicate write inode for truncating file
> exfat: remove duplicate write inode for extending dir/file
>
> fs/exfat/exfat_fs.h | 1 +
> fs/exfat/file.c | 82 ++++++++++++++-------------------------------
> fs/exfat/inode.c | 41 ++++++-----------------
> fs/exfat/namei.c | 20 -----------
> 4 files changed, 37 insertions(+), 107 deletions(-)
Applied, Thanks for your work!
>
> --
> 2.25.1
>
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