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From: Chris Murphy <chris@colorremedies.com>
To: Qu Wenruo <quwenruo.btrfs@gmx.com>
Cc: Btrfs BTRFS <linux-btrfs@vger.kernel.org>
Subject: Re: dump tree always shows compression level 3, zstd
Date: Sat, 21 Dec 2019 11:51:23 -0700	[thread overview]
Message-ID: <CAJCQCtSyQxZWxfnW9pPx2=EN7dn0+6-w_7MT3r5LSj6yqvjY5Q@mail.gmail.com> (raw)
In-Reply-To: <6eaa5006-038c-c543-f714-279998168476@gmx.com>

On Fri, Dec 20, 2019 at 11:34 PM Qu Wenruo <quwenruo.btrfs@gmx.com> wrote:
>
>
>
> On 2019/12/21 下午2:27, Chris Murphy wrote:
> > kernel 5.4.5
> > btrfs-progs 5.4
> >
> > test file is linux.tar (not compressed), it's the only file on the
> > file system in each case
> >
> > /dev/sda5        53G  2.8G   50G   6% /mnt     none
> > /dev/sda5        53G  2.2G   50G   5% /mnt     zstd 1
> > /dev/sda5        53G  2.1G   50G   4% /mnt     zstd 15
> >
> >
> > mount and dmesg both show the value for the level I've set; but btrfs
> > insp dump-t shows extents always have compression 3.
> >
> >
> > [47567.500812] BTRFS info (device sda5): use zstd compression, level 1
> >
> >     item 14 key (328583 EXTENT_DATA 2060582912) itemoff 15488 itemsize 53
> >         generation 51 type 1 (regular)
> >         extent data disk byte 6461308928 nr 20480
> >         extent data offset 0 nr 131072 ram 131072
> >         extent compression 3 (zstd)
>
> This number is not compression level, but compression algorithm.
>
> typedef enum {
>         BTRFS_COMPRESS_NONE  = 0,
>         BTRFS_COMPRESS_ZLIB  = 1,
>         BTRFS_COMPRESS_LZO   = 2,
>         BTRFS_COMPRESS_ZSTD  = 3,
>         BTRFS_COMPRESS_TYPES = 3,
>         BTRFS_COMPRESS_LAST  = 4,
> } btrfs_compression_type;
>
> Level is not recorded in that field.

Oh lovely, that's embarrassing. Thanks for the answer!


-- 
Chris Murphy

      reply	other threads:[~2019-12-21 18:51 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-21  6:27 dump tree always shows compression level 3, zstd Chris Murphy
2019-12-21  6:34 ` Qu Wenruo
2019-12-21 18:51   ` Chris Murphy [this message]

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