Re: [f2fs-dev] [PATCH v2 00/13] f2fs: introduce inline tail
From: Wu Bo
Date: Sat Sep 14 2024 - 05:06:26 EST
On Fri, Sep 13, 2024 at 08:41:12PM -0600, Wu Bo via Linux-f2fs-devel wrote:
> On Thu, Sep 12, 2024 at 03:14:24PM +0800, Chao Yu via Linux-f2fs-devel wrote:
> > On 2024/9/11 11:57, Wu Bo wrote:
> > > The inode in F2FS occupies an entire 4k block. For many small files, this means
> > > they consume much more space than their actual size. Therefore, there is
> > > significant potential to better utilize the inode block space.
> > >
> > > Currently, F2FS has two features to make use of the inode block space: inline
> > > data and inline xattr.
> > >
> > > Inline data stores file which size is smaller then 3.5k in inode block. However,
> > > for slightly larger small files, there still have much waste.
> > > For example, a 5k file requires 3 blocks, totaling 12k of space, which is
> > > more than twice the size of the file itself!
> > >
> > > Additionally, the end of a file often does not occupy an entire block. If we can
> > > store the end of the file data within the inode block, we can save an entire
> > > block for the file. This is particularly important for small files.
> > >
> > > In fact, the current inline data is a special case of inline tail, and
> > > inline tail is an extension of inline data.
> > >
> > > To make it simple, inline tail only on small files(<64k). And for larger files,
> > > inline tails don't provide any significant benefits.
> > >
> > > The layout of an inline tail inode block is following:
> > >
> > > | inode block | 4096 | inline tail enable |
> > > | --------------- | ---- | --------------------------|
> > > | inode info | 360 | |
> > > | --------------- | ---- | --------------------------|
> > > | | | extra info | 0~36 |
> > > | | | **compact_addr[16] | 64 |
> > > | addr table[923] | 3692 | reserved | 4 |
> > > | | | **tail data | |
> > > | | | inline_xattr | 200 |
> > > | --------------- | ---- | --------------------------|
> > > | nid table[5] | 20 |
> > > | node footer | 24 |
> > >
> > > F2fs-tools to support inline tail:
> > > https://lore.kernel.org/linux-f2fs-devel/20240903075931.3339584-1-bo.wu@xxxxxxxx
> > >
> > > I tested inline tail by copying the source code of Linux 6.9.7. The storage
> > > space was reduced by approximately 8%. Additionally, due to the reduced IO, the
> > > copy time also reduced by around 10%.
> > >
> > > This patch series has been tested with xfstests by running 'kvm-xfstests -c f2fs
> > > -g quick' both with and without the patch; no regressions were observed.
> > > The test result is:
> > > f2fs/default: 583 tests, 6 failures, 213 skipped, 650 seconds
> > > Failures: generic/050 generic/064 generic/250 generic/252 generic/563
> > > generic/735
> > > Totals: 607 tests, 213 skipped, 30 failures, 0 errors, 579s
> >
> > MKFS_OPTIONS -- -O extra_attr,encrypt,inode_checksum,flexible_inline_xattr,inode_crtime,verity,compression -f /dev/vdc
> > MOUNT_OPTIONS -- -o acl,user_xattr -o discard,inline_tail /dev/vdc /mnt/scratch_f2fs
>
> Hi Chao,
>
> I used the default cfg to run xfstest-bld and didn't encounter the failed
> failures. This suggests the issue might be related to these additional options.
> However, I'm not sure how to include these options when running xfstest-bld.
> Could you let me know how to add them?
>
> Thanks
I found how to pass these options:
1. Add custom config file
```
# cat test-appliance/files/root/fs/f2fs/cfg/custom
SIZE=small
export MKFS_OPTIONS="-O extra_attr,encrypt,inode_checksum,flexible_inline_xattr,inode_crtime,verity,compression -f"
export F2FS_MOUNT_OPTIONS="discard,inline_tail"
TESTNAME="f2fs custom"
```
2. Then run command as following:
```
kvm-xfstests -c f2fs/custom "generic/418"
```
However, I am only able to reproduce generic/418 and f2fs/004. I will look into
these two cases first.
>
> >
> > Before:
> > Failures: generic/042 generic/050 generic/250 generic/252 generic/270 generic/389 generic/563 generic/700 generic/735
> > Failed 9 of 746 tests
> >
> > After:
> > Failures: generic/042 generic/050 generic/125 generic/250 generic/252 generic/270 generic/389 generic/418 generic/551 generic/563 generic/700 generic/735
> > Failed 12 of 746 tests
> >
> > Failures: f2fs/004
> >
> > Can you please check failed testcases?
> >
> > Thanks,
> >
> > >
> > > ---
> > > v2:
> > > - fix ARCH=arc build warning
> > >
> > > ---
> > > Wu Bo (13):
> > > f2fs: add inline tail mount option
> > > f2fs: add inline tail disk layout definition
> > > f2fs: implement inline tail write & truncate
> > > f2fs: implement inline tail read & fiemap
> > > f2fs: set inline tail flag when create inode
> > > f2fs: fix address info has been truncated
> > > f2fs: support seek for inline tail
> > > f2fs: convert inline tail when inode expand
> > > f2fs: fix data loss during inline tail writing
> > > f2fs: avoid inlining quota files
> > > f2fs: fix inline tail data lost
> > > f2fs: convert inline tails to avoid potential issues
> > > f2fs: implement inline tail forward recovery
> > >
> > > fs/f2fs/data.c | 93 +++++++++++++++++++++++++-
> > > fs/f2fs/f2fs.h | 46 ++++++++++++-
> > > fs/f2fs/file.c | 85 +++++++++++++++++++++++-
> > > fs/f2fs/inline.c | 159 +++++++++++++++++++++++++++++++++++++++------
> > > fs/f2fs/inode.c | 6 ++
> > > fs/f2fs/namei.c | 3 +
> > > fs/f2fs/node.c | 6 +-
> > > fs/f2fs/recovery.c | 9 ++-
> > > fs/f2fs/super.c | 25 +++++++
> > > fs/f2fs/verity.c | 4 ++
> > > 10 files changed, 409 insertions(+), 27 deletions(-)
> > >
> > >
> > > base-commit: 67784a74e258a467225f0e68335df77acd67b7ab
> >
> >
> >
> > _______________________________________________
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>
>
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