Re: [PATCH 00/32] e2fsprogs: make e2fsprogs support inline data

[Tao Ma <tm@tao.ma>]

On 04/16/2012 11:08 PM, Andreas Dilger wrote:
> On 2012-04-16, at 4:39 AM, Zheng Liu wrote:
>> Here is v2 for making e2fsprogs support inline data.  Now debugfs
>> supports inline data in read-write mode.  Meanwhile e2fsck has
>> been improved to support inline data feature.
>>
>> v1->v2:
>> * [mke2fs] automatically set EXT_ATTR feature when INLINE_DATA is set
>> * [debugfs] supports read-write mode
> 
> As with the previous patch series, there is a need to show some
> benchmark data that indicates how much improvement this feature
> provides.  Some examples would include percentage of directories
> stored inline (e.g. in a typical distro installation), performance
> improvement (e.g. cold-cache filesystem traversal).  It is likely
> that these improvements will be more visible with bigalloc enabled
> for a large cluster size (e.g. space savings).
yeah, I am doing some benchmark test and collect the data. They will be
available when I send out the new version.
> 
> Without a clear indication of performance improvement, the patch
> cannot be included due to added complexity and unclear benefits.
sure, please wait for the kernel patches. :)
> 
>> In mke2fs, EXT4_FEATURE_INCOMPAT_INLINE_DATA is set to 0x2000 to
>> consist with kernel.  When making a new ext4 file system with
>> INLINE_DATA feature, mke2fs will check whether EXT_ATTR is set or
>> not.  If it is not set, mke2fs will mark it automatically because
>> INLINE_DATA depends on it.
>>
>> In debugfs, it can support inline data in read-write mode.  Now
>> there is two problems that need to be solved.  No matter whether
>> the size of data is fit into inline data or not, 'write' command
>> writes the data into disk blocks rather than inode itself.  'mkdir'
>> command will expand dir to a new disk block when inode->i_block
>> has full because Tao found a performance regression when a huge
>> number of dirs are added and removed in EA space.  It causes that
>> the code in kernel might be changed.  So now 'mkdir' cmd doesn't
>> add a new dir entry in EA space.
>>
>> TODO list:
>> * [mke2fs] initialize ROOT dir with inline data flag
>> * [mke2fs] initialize LOST+FOUND dir with inline data flag
> 
> Note that it does not make sense to store lost+found inline.  It
> is purposely created with multiple leaf blocks so that blocks
> do not need to be allocated during e2fsck runs.  Probably the
> same is true for root - it will almost certainly immediately
> be moved out of the inode due to file creations.
fair enough.

Thanks
Tao
> 
> Cheers, Andreas
> 
>> * [debugfs] 'write' cmd writes the data into inode itself
>> * [debugfs] 'mkdir' cmd add dir entry into EA space
>>
>> Regards,
>> Zheng
>>
>> libext2fs: add EXT4_FEATURE_INCOMPAT_INLINE_DATA flag
>> mke2fs: make it support inline data feature
>> libext2fs: add inline_data feature
>> mke2fs: add inline_data feature in mke2fs's manpage
>> libext2fs: add ext2fs_find_entry_ext_attr function
>> libext2fs: add EXT4_INLINE_DATA_FL flag for inode
>> libext2fs: add data structures for inline data feature
>> libext2fs: add inline_data file
>> debugfs: make ncheck cmd support inline data
>> debugfs: make chroot and cd cmd support inline data
>> debugfs: make ls cmd support inline data
>> debugfs: make stat cmd support inline data
>> debufs: make blocks cmd support inline data
>> debugfs: make filefrag cmd support inline data
>> debugfs: make link cmd support inline data
>> debugfs: make unlink cmd support inline data
>> debugfs: make mkdir cmd support inline data
>> debugfs: make rmdir cmd support inline data
>> debugfs: make rm and kill_file cmd support inline data
>> debugfs: make pwd cmd support inline data
>> debugfs: make expand_dir cmd support inline data
>> debugfs: make lsdel cmd support inline data
>> debugfs: make undel cmd support inline data
>> debugfs: make dump and cat cmd support inline data
>> debugfs: make rdump cmd support inline data
>> debugfs: make dirsearch cmd support inline data
>> debugfs: make bma cmd support inline data
>> e2fsck: add three problem descriptions in pass1
>> e2fsck: check incorrect inline data flag
>> e2fsck: make pass1 support inline data
>> libext2fs: add read/write inline data functions
>> e2fsck: check inline data in pass2
>>
>> debugfs/debugfs.c          |   25 ++-
>> debugfs/dump.c             |   38 +++-
>> debugfs/filefrag.c         |   30 ++-
>> debugfs/htree.c            |    6 +
>> debugfs/ls.c               |    8 +-
>> debugfs/lsdel.c            |   19 +-
>> debugfs/ncheck.c           |    8 +-
>> e2fsck/pass1.c             |   70 ++++-
>> e2fsck/pass1b.c            |    5 +-
>> e2fsck/pass2.c             |   50 +++-
>> e2fsck/problem.c           |   15 +
>> e2fsck/problem.h           |    9 +
>> lib/e2p/feature.c          |    2 +
>> lib/ext2fs/Makefile.in     |    5 +
>> lib/ext2fs/Makefile.pq     |    1 +
>> lib/ext2fs/bmap.c          |   16 +
>> lib/ext2fs/dblist_dir.c    |    8 +-
>> lib/ext2fs/dirblock.c      |   62 ++++
>> lib/ext2fs/expanddir.c     |    8 +-
>> lib/ext2fs/ext2_ext_attr.h |    4 +
>> lib/ext2fs/ext2_fs.h       |    9 +
>> lib/ext2fs/ext2fs.h        |   69 ++++-
>> lib/ext2fs/ext_attr.c      |   26 ++
>> lib/ext2fs/get_pathname.c  |    7 +-
>> lib/ext2fs/inline_data.c   |  715 ++++++++++++++++++++++++++++++++++++++++++++
>> lib/ext2fs/link.c          |    9 +-
>> lib/ext2fs/lookup.c        |    6 +-
>> lib/ext2fs/mkdir.c         |    4 +
>> lib/ext2fs/unlink.c        |    9 +-
>> misc/mke2fs.8.in           |    3 +
>> misc/mke2fs.c              |   10 +-
>> 31 files changed, 1197 insertions(+), 59 deletions(-)
>> --
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> 
> 
> Cheers, Andreas
> 
> 
> 
> 
> 
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