On Sat, May 11, 2024 at 01:01:46PM +0800, Zorro Lang wrote: > Hi Darrick, > > Due to only half of this patchset got reviewed, so I'd like to wait for your > later version. I won't pick up part of this patchset to merge this time, I > think better to merge it as an integrated patchset. Christoph and I talked about the future of this patchset at LSF and there are some file format changes in store, so please hold off on analyzing this patchset for now. --D > Thanks, > Zorro > > On Mon, Apr 29, 2024 at 08:19:24PM -0700, Darrick J. Wong wrote: > > Hi all, > > > > This patchset adds support for fsverity to XFS. In keeping with > > Andrey's original design, XFS stores all fsverity metadata in the > > extended attribute data. However, I've made a few changes to the code: > > First, it now caches merkle tree blocks directly instead of abusing the > > buffer cache. This reduces lookup overhead quite a bit, at a cost of > > needing a new shrinker for cached merkle tree blocks. > > > > To reduce the ondisk footprint further, I also made the verity > > enablement code detect trailing zeroes whenever fsverity tells us to > > write a buffer, and elide storing the zeroes. To further reduce the > > footprint of sparse files, I also skip writing merkle tree blocks if the > > block contents are entirely hashes of zeroes. > > > > Next, I implemented more of the tooling around verity, such as debugger > > support, as much fsck support as I can manage without knowing the > > internal format of the fsverity information; and added support for > > xfs_scrub to read fsverity files to validate the consistency of the data > > against the merkle tree. > > > > Finally, I add the ability for administrators to turn off fsverity, > > which might help recovering damaged data from an inconsistent file. > > > > From Andrey Albershteyn: > > > > Here's v5 of my patchset of adding fs-verity support to XFS. > > > > This implementation uses extended attributes to store fs-verity > > metadata. The Merkle tree blocks are stored in the remote extended > > attributes. The names are offsets into the tree. > > From Darrick J. Wong: > > > > This v5.3 patchset builds upon v5.2 of Andrey's patchset to implement > > fsverity for XFS. > > > > The biggest thing that I didn't like in the v5 patchset is the abuse of > > the data device's buffer cache to store the incore version of the merkle > > tree blocks. Not only do verity state flags end up in xfs_buf, but the > > double-alloc flag wastes memory and doesn't remain internally consistent > > if the xattrs shift around. > > > > I replaced all of that with a per-inode xarray that indexes incore > > merkle tree blocks. For cache hits, this dramatically reduces the > > amount of work that xfs has to do to feed fsverity. The per-block > > overhead is much lower (8 bytes instead of ~300 for xfs_bufs), and we no > > longer have to entertain layering violations in the buffer cache. I > > also added a per-filesystem shrinker so that reclaim can cull cached > > merkle tree blocks, starting with the leaf tree nodes. > > > > I've also rolled in some changes recommended by the fsverity maintainer, > > fixed some organization and naming problems in the xfs code, fixed a > > collision in the xfs_inode iflags, and improved dead merkle tree cleanup > > per the discussion of the v5 series. At this point I'm happy enough > > with this code to start integrating and testing it in my trees, so it's > > time to send it out a coherent patchset for comments. > > > > For v5.3, I've added bits and pieces of online and offline repair > > support, reduced the size of partially filled merkle tree blocks by > > removing trailing zeroes, changed the xattr hash function to better > > avoid collisions between merkle tree keys, made the fsverity > > invalidation bitmap unnecessary, and made it so that we can save space > > on sparse verity files by not storing merkle tree blocks that hash > > totally zeroed data blocks. > > > > From Andrey Albershteyn: > > > > Here's v5 of my patchset of adding fs-verity support to XFS. > > > > This implementation uses extended attributes to store fs-verity > > metadata. The Merkle tree blocks are stored in the remote extended > > attributes. The names are offsets into the tree. > > > > If you're going to start using this code, I strongly recommend pulling > > from my git trees, which are linked below. > > > > This has been running on the djcloud for months with no problems. Enjoy! > > Comments and questions are, as always, welcome. > > > > --D > > > > kernel git tree: > > https://git.kernel.org/cgit/linux/kernel/git/djwong/xfs-linux.git/log/?h=fsverity > > > > xfsprogs git tree: > > https://git.kernel.org/cgit/linux/kernel/git/djwong/xfsprogs-dev.git/log/?h=fsverity > > > > fstests git tree: > > https://git.kernel.org/cgit/linux/kernel/git/djwong/xfstests-dev.git/log/?h=fsverity > > --- > > Commits in this patchset: > > * common/verity: enable fsverity for XFS > > * xfs/{021,122}: adapt to fsverity xattrs > > * xfs/122: adapt to fsverity > > * xfs: test xfs_scrub detection and correction of corrupt fsverity metadata > > * xfs: test disabling fsverity > > * common/populate: add verity files to populate xfs images > > --- > > common/populate | 24 +++++++++ > > common/verity | 39 ++++++++++++++- > > tests/xfs/021 | 3 + > > tests/xfs/122.out | 3 + > > tests/xfs/1880 | 135 ++++++++++++++++++++++++++++++++++++++++++++++++++++ > > tests/xfs/1880.out | 37 ++++++++++++++ > > tests/xfs/1881 | 111 +++++++++++++++++++++++++++++++++++++++++++ > > tests/xfs/1881.out | 28 +++++++++++ > > 8 files changed, 378 insertions(+), 2 deletions(-) > > create mode 100755 tests/xfs/1880 > > create mode 100644 tests/xfs/1880.out > > create mode 100755 tests/xfs/1881 > > create mode 100644 tests/xfs/1881.out > > > >
