From: "Darrick J. Wong" <djwong@kernel.org>
To: Amir Goldstein <amir73il@gmail.com>
Cc: linux-fsdevel <linux-fsdevel@vger.kernel.org>,
John@groves.net, bernd@bsbernd.com, miklos@szeredi.hu,
joannelkoong@gmail.com, Josef Bacik <josef@toxicpanda.com>,
linux-ext4 <linux-ext4@vger.kernel.org>,
Theodore Ts'o <tytso@mit.edu>,
Matthew Wilcox <willy@infradead.org>
Subject: [RFC[RAP] V2] fuse: use fs-iomap for better performance so we can containerize ext4
Date: Fri, 13 Jun 2025 10:37:10 -0700 [thread overview]
Message-ID: <20250613173710.GL6138@frogsfrogsfrogs> (raw)
In-Reply-To: <CAOQ4uxh3vW5z_Q35DtDhhTWqWtrkpFzK7QUsw3MGLPY4hqUxLw@mail.gmail.com>
On Thu, May 22, 2025 at 06:24:50PM +0200, Amir Goldstein wrote:
> On Thu, May 22, 2025 at 1:58 AM Darrick J. Wong <djwong@kernel.org> wrote:
> >
> > Hi everyone,
> >
> > DO NOT MERGE THIS.
Three weeks later, I've mostly gotten the iomap caching working. This
is probably most exciting for John, because we were talking earlier
about uploading storage mappings to the fuse driver and this is what
I've come up with. I'm running around trying to fix all the stuff that
doesn't quite work right.
Top of that list is timestamps and file attributes, because fuse no
longer calls the fuse server for file writes. As a result, the kernel
inode always has the most uptodate versions of the some file attributes
(i_size, timestamps, mode) and just want to send FUSE_SETATTR whenever
the dirty inode gets flushed.
After I get that working I'm going to have to rewrite fuse2fs (or more
likely just fork it) to be a lowlevel driver because as I've noted
elsewhere in this thread, the upper level fuse library can assign
multiple fuse nodeids for a single hardlinked inode. The only reason
that worked for non-iomap fuse2fs is because we have a BKL and disable
all caching.
For fuse+iomap, this discrepancy between fuse nodeids and ext2 inumbers
means that iomap just plain doesn't work with hardlinks because there
are multiple struct fuse_inodes for each ondisk inode and the locking is
just broken; and the iomap callouts are per-inode, not per-file which
leads to multiple layering violations in the upper level fuse library.
Also as Amir points out, path lookups on every operation is just *slow*.
Interim branches can be found here:
https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux.git/log/?h=fuse-iomap-cache_2025-06-13
https://git.kernel.org/pub/scm/linux/kernel/git/djwong/libfuse.git/log/?h=fuse-iomap-cache_2025-06-13
https://git.kernel.org/pub/scm/linux/kernel/git/djwong/e2fsprogs.git/log/?h=fuse2fs-iomap-cache_2025-06-13
https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfstests-dev.git/log/?h=fuse2fs_2025-06-13
(I'm not going to respam the list with patches right now because the
quality as told by fstests isn't quite where I want it to be for such a
thing. fuse2fs+iomap passes 87% of fstests (down from 89% without
iomap) but that's still pretty bad.)
--D
next prev parent reply other threads:[~2025-06-13 17:37 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-05-21 23:58 [RFC[RAP]] fuse: use fs-iomap for better performance so we can containerize ext4 Darrick J. Wong
2025-05-22 0:01 ` [PATCHSET 1/3] fuse2fs: upgrade to libfuse 3.17 Darrick J. Wong
2025-05-22 0:07 ` [PATCH 1/3] fuse2fs: bump library version Darrick J. Wong
2025-05-22 0:07 ` [PATCH 2/3] fuse2fs: wrap the fuse_set_feature_flag helper for older libfuse Darrick J. Wong
2025-05-22 0:08 ` [PATCH 3/3] fuse2fs: disable nfs exports Darrick J. Wong
2025-05-22 0:02 ` [PATCHSET RFC[RAP] 2/3] libext2fs: refactoring for fuse2fs iomap support Darrick J. Wong
2025-05-22 0:08 ` [PATCH 01/10] libext2fs: always fsync the device when flushing the cache Darrick J. Wong
2025-05-22 0:08 ` [PATCH 02/10] libext2fs: always fsync the device when closing the unix IO manager Darrick J. Wong
2025-05-22 0:09 ` [PATCH 03/10] libext2fs: only fsync the unix fd if we wrote to the device Darrick J. Wong
2025-05-22 0:09 ` [PATCH 04/10] libext2fs: invalidate cached blocks when freeing them Darrick J. Wong
2025-05-22 0:09 ` [PATCH 05/10] libext2fs: add tagged block IO for better caching Darrick J. Wong
2025-05-22 0:09 ` [PATCH 06/10] libext2fs: add tagged block IO caching to the unix IO manager Darrick J. Wong
2025-05-22 0:10 ` [PATCH 07/10] libext2fs: only flush affected blocks in unix_write_byte Darrick J. Wong
2025-05-22 0:10 ` [PATCH 08/10] libext2fs: allow unix_write_byte when the write would be aligned Darrick J. Wong
2025-05-22 0:10 ` [PATCH 09/10] libext2fs: allow clients to ask to write full superblocks Darrick J. Wong
2025-05-22 0:10 ` [PATCH 10/10] libext2fs: allow callers to disallow I/O to file data blocks Darrick J. Wong
2025-05-22 0:02 ` [PATCHSET RFC[RAP] 3/3] fuse2fs: use fuse iomap data paths for better file I/O performance Darrick J. Wong
2025-05-22 0:11 ` [PATCH 01/16] fuse2fs: implement bare minimum iomap for file mapping reporting Darrick J. Wong
2025-05-22 0:11 ` [PATCH 02/16] fuse2fs: register block devices for use with iomap Darrick J. Wong
2025-05-22 0:11 ` [PATCH 03/16] fuse2fs: always use directio disk reads with fuse2fs Darrick J. Wong
2025-05-22 0:11 ` [PATCH 04/16] fuse2fs: implement directio file reads Darrick J. Wong
2025-05-22 0:12 ` [PATCH 05/16] fuse2fs: use tagged block IO for zeroing sub-block regions Darrick J. Wong
2025-05-22 0:12 ` [PATCH 06/16] fuse2fs: only flush the cache for the file under directio read Darrick J. Wong
2025-05-22 0:12 ` [PATCH 07/16] fuse2fs: add extent dump function for debugging Darrick J. Wong
2025-05-22 0:12 ` [PATCH 08/16] fuse2fs: implement direct write support Darrick J. Wong
2025-05-22 0:13 ` [PATCH 09/16] fuse2fs: turn on iomap for pagecache IO Darrick J. Wong
2025-05-22 0:13 ` [PATCH 10/16] fuse2fs: flush and invalidate the buffer cache on trim Darrick J. Wong
2025-05-22 0:13 ` [PATCH 11/16] fuse2fs: improve tracing for fallocate Darrick J. Wong
2025-05-22 0:13 ` [PATCH 12/16] fuse2fs: don't zero bytes in punch hole Darrick J. Wong
2025-05-22 0:14 ` [PATCH 13/16] fuse2fs: don't do file data block IO when iomap is enabled Darrick J. Wong
2025-05-22 0:14 ` [PATCH 14/16] fuse2fs: disable most io channel flush/invalidate in iomap pagecache mode Darrick J. Wong
2025-05-22 0:14 ` [PATCH 15/16] fuse2fs: re-enable the block device pagecache for metadata IO Darrick J. Wong
2025-05-22 0:15 ` [PATCH 16/16] fuse2fs: avoid fuseblk mode if fuse-iomap support is likely Darrick J. Wong
2025-05-22 16:24 ` [RFC[RAP]] fuse: use fs-iomap for better performance so we can containerize ext4 Amir Goldstein
2025-05-29 16:45 ` Darrick J. Wong
2025-05-29 19:41 ` Amir Goldstein
2025-06-09 22:31 ` Darrick J. Wong
2025-06-10 10:59 ` Amir Goldstein
2025-06-10 19:00 ` Darrick J. Wong
2025-06-10 19:51 ` Amir Goldstein
2025-06-11 6:00 ` Darrick J. Wong
2025-06-11 8:54 ` Amir Goldstein
2025-06-12 5:54 ` Miklos Szeredi
2025-06-13 17:44 ` Darrick J. Wong
2025-06-11 11:56 ` Theodore Ts'o
2025-06-12 3:20 ` Darrick J. Wong
2025-06-12 6:10 ` Amir Goldstein
2025-06-20 8:58 ` Allison Karlitskaya
2025-06-20 11:50 ` Bernd Schubert
2025-07-01 6:02 ` Darrick J. Wong
2025-07-01 5:58 ` Darrick J. Wong
2025-07-12 10:57 ` Amir Goldstein
2025-06-13 17:37 ` Darrick J. Wong [this message]
2025-06-23 13:16 ` [RFC[RAP] V2] " Miklos Szeredi
2025-07-01 6:05 ` Darrick J. Wong
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