Thanks, I got it.
-----邮件原件----- 发件人: Chao Yu <[email protected]> 发送时间: 2021年4月13日 9:16 收件人: Fengnan Chang <[email protected]> 抄送: [email protected]; [email protected]; [email protected] 主题: Re: [f2fs-dev] [f2fs-devel] Why does f2fs not reduce disk space when compression is on? On 2021/4/12 21:13, Fengnan Chang wrote: > I'm testing the f2fs data compression feature. I created a new FS with > the flags extra_attr and compression, use chattr -R +c on the test dir to enable compression for the directory. > I found that when compression was turned on, the files did not take up any less space. > Using trace, I see that the data is indeed compressed. > Is there a mistake in my testing method, or is this how it was designed and why? https://lore.kernel.org/lkml/[email protected]/ I guess we should document it well in f2fs.rst to avoid any confusion, let me post a patch for that soon. Thanks, > > This is my test method: > > # mount > /dev/nvme0n1 on /mnt type f2fs > (rw,lazytime,relatime,background_gc=on,discard,no_heap,user_xattr,inli > ne_xattr,acl,inline_data,inline_dentry,flush_merge,extent_cache,mode=a > daptive,active_logs=6,alloc_mode=reuse,fsync_mode=posix,compress_algor > ithm=lz4,compress_log_size=2) > # df > Filesystem 1K-blocks Used Available Use% Mounted on > /dev/root 114901 112444 0 100% / > devtmpfs 497436 0 497436 0% /dev > tmpfs 500060 0 500060 0% /dev/shm > tmpfs 500060 52 500008 0% /tmp > tmpfs 500060 20 500040 0% /run > /dev/nvme0n1 10483712 499724 9983988 5% /mnt > # mkdir test > # chattr -R +c test/ > # dd if=/dev/zero of=/mnt/test/file bs=1M count=100 # sync # df > Filesystem 1K-blocks Used Available Use% Mounted on > /dev/root 114901 112444 0 100% / > devtmpfs 497436 0 497436 0% /dev > tmpfs 500060 0 500060 0% /dev/shm > tmpfs 500060 368 499692 0% /tmp > tmpfs 500060 20 500040 0% /run > /dev/nvme0n1 10483712 602232 9881480 6% /mnt > > > _______________________________________________ > Linux-f2fs-devel mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel > . > _______________________________________________ Linux-f2fs-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
