Hi Wu, Interesting patch-set.
A quick test here on my daily-driver phone's data (785558 inodes) with both compression and encryption disabled, copied via rsync to 2 fresh f2fs partitions with and without inline tail: Before: 170064928KiB After: 169249780KiB So about 0.48% saved. Let me know if this is an unexpected result. Thanks, On Tue, Sep 3, 2024 at 5:42 PM Wu Bo via Linux-f2fs-devel <linux-f2fs-devel@lists.sourceforge.net> 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...@vivo.com > > 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 > > 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(-) > > -- > 2.35.3 > > > > _______________________________________________ > Linux-f2fs-devel mailing list > Linux-f2fs-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel _______________________________________________ Linux-f2fs-devel mailing list Linux-f2fs-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
