From: Konstantin Komarov > Sent: Friday, December 11, 2020 7:28 PM > To: 'Eric Biggers' <ebiggers@xxxxxxxxxx> > Cc: linux-fsdevel@xxxxxxxxxxxxxxx; viro@xxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; pali@xxxxxxxxxx; dsterba@xxxxxxx; > aaptel@xxxxxxxx; willy@xxxxxxxxxxxxx; rdunlap@xxxxxxxxxxxxx; joe@xxxxxxxxxxx; mark@xxxxxxxxxxxxx; nborisov@xxxxxxxx; > linux-ntfs-dev@xxxxxxxxxxxxxxxxxxxxx; anton@xxxxxxxxxx; dan.carpenter@xxxxxxxxxx; hch@xxxxxx > Subject: RE: [PATCH v14 06/10] fs/ntfs3: Add compression > > From: Eric Biggers <ebiggers@xxxxxxxxxx> > Sent: Friday, December 4, 2020 9:39 PM > > To: Konstantin Komarov <almaz.alexandrovich@xxxxxxxxxxxxxxxxxxxx> > > Cc: linux-fsdevel@xxxxxxxxxxxxxxx; viro@xxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; pali@xxxxxxxxxx; dsterba@xxxxxxx; > > aaptel@xxxxxxxx; willy@xxxxxxxxxxxxx; rdunlap@xxxxxxxxxxxxx; joe@xxxxxxxxxxx; mark@xxxxxxxxxxxxx; nborisov@xxxxxxxx; > > linux-ntfs-dev@xxxxxxxxxxxxxxxxxxxxx; anton@xxxxxxxxxx; dan.carpenter@xxxxxxxxxx; hch@xxxxxx > > Subject: Re: [PATCH v14 06/10] fs/ntfs3: Add compression > > > > On Fri, Dec 04, 2020 at 06:45:56PM +0300, Konstantin Komarov wrote: > > > This adds compression > > > > > > Signed-off-by: Konstantin Komarov <almaz.alexandrovich@xxxxxxxxxxxxxxxxxxxx> > > > --- > > > fs/ntfs3/lib/common_defs.h | 196 +++++++++++ > > > fs/ntfs3/lib/decompress_common.c | 314 +++++++++++++++++ > > > fs/ntfs3/lib/decompress_common.h | 558 +++++++++++++++++++++++++++++++ > > > fs/ntfs3/lib/lzx_common.c | 204 +++++++++++ > > > fs/ntfs3/lib/lzx_common.h | 31 ++ > > > fs/ntfs3/lib/lzx_constants.h | 113 +++++++ > > > fs/ntfs3/lib/lzx_decompress.c | 553 ++++++++++++++++++++++++++++++ > > > fs/ntfs3/lib/xpress_constants.h | 23 ++ > > > fs/ntfs3/lib/xpress_decompress.c | 165 +++++++++ > > > fs/ntfs3/lznt.c | 452 +++++++++++++++++++++++++ > > > 10 files changed, 2609 insertions(+) > > > create mode 100644 fs/ntfs3/lib/common_defs.h > > > create mode 100644 fs/ntfs3/lib/decompress_common.c > > > create mode 100644 fs/ntfs3/lib/decompress_common.h > > > create mode 100644 fs/ntfs3/lib/lzx_common.c > > > create mode 100644 fs/ntfs3/lib/lzx_common.h > > > create mode 100644 fs/ntfs3/lib/lzx_constants.h > > > create mode 100644 fs/ntfs3/lib/lzx_decompress.c > > > create mode 100644 fs/ntfs3/lib/xpress_constants.h > > > create mode 100644 fs/ntfs3/lib/xpress_decompress.c > > > create mode 100644 fs/ntfs3/lznt.c > > > > This really could use a much better commit message. Including mentioning where > > the LZX and XPRESS decompression code came from > > (https://github.com/ebiggers/ntfs-3g-system-compression). > > > > Hi Eric! Fixed in V15! > > > Also note you've marked the files as "SPDX-License-Identifier: GPL-2.0", > > but they really are "SPDX-License-Identifier: GPL-2.0-or-later". > > > > Thanks, fixed as well. > > > Also I still think you should consider using the simpler version from > > ntfs-3g-system-compression commit 3ddd227ee8e3, which I had originally intended > > to be included in NTFS-3G itself. That version was fewer lines of code and > > fewer files, as it was simplified for decompression-only. The latest version > > (the one you're using) is shared with a project that also implements compression > > (so that I can more easily maintain both projects), so it's more complex than > > needed for decompression-only support. But in the kernel context it may make > > sense to go with a simpler version. There are a few performance optimizations > > you'd miss by going with the older version, but they weren't too significant, > > and probably you don't need to squeeze out every bit of performance possible > > when reading XPRESS and LZX-compressed files in this context? > > > > - Eric > > We used the newest code initially. Looking at the commit you've pointed out, but it will > take some time as needs to pass full set of tests with new code. On the differences you've > mentioned between the first and latest code in ntfs-3g system compression: we've removed > the optimizations (needed to go into kernel), also the reparse points stuff is being parsed by > ntfs3 driver itself. Given this, doesn't seems there are many differences remain. > Also, we'll follow your recommendations, if you highly recommend to stick to the commit > you've mentioned (but at this moment it seems "newer=better" formula still valid). > > Thanks! Hi Eric! The code in V16 is now based on the initial ntfs-3g plugin code, just as you suggested. Best regards.
