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* Merge tag 'mm-stable-2023-04-27-15-30' of ↵Linus Torvalds2023-04-271-2/+4
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Pull MM updates from Andrew Morton: - Nick Piggin's "shoot lazy tlbs" series, to improve the peformance of switching from a user process to a kernel thread. - More folio conversions from Kefeng Wang, Zhang Peng and Pankaj Raghav. - zsmalloc performance improvements from Sergey Senozhatsky. - Yue Zhao has found and fixed some data race issues around the alteration of memcg userspace tunables. - VFS rationalizations from Christoph Hellwig: - removal of most of the callers of write_one_page() - make __filemap_get_folio()'s return value more useful - Luis Chamberlain has changed tmpfs so it no longer requires swap backing. Use `mount -o noswap'. - Qi Zheng has made the slab shrinkers operate locklessly, providing some scalability benefits. - Keith Busch has improved dmapool's performance, making part of its operations O(1) rather than O(n). - Peter Xu adds the UFFD_FEATURE_WP_UNPOPULATED feature to userfaultd, permitting userspace to wr-protect anon memory unpopulated ptes. - Kirill Shutemov has changed MAX_ORDER's meaning to be inclusive rather than exclusive, and has fixed a bunch of errors which were caused by its unintuitive meaning. - Axel Rasmussen give userfaultfd the UFFDIO_CONTINUE_MODE_WP feature, which causes minor faults to install a write-protected pte. - Vlastimil Babka has done some maintenance work on vma_merge(): cleanups to the kernel code and improvements to our userspace test harness. - Cleanups to do_fault_around() by Lorenzo Stoakes. - Mike Rapoport has moved a lot of initialization code out of various mm/ files and into mm/mm_init.c. - Lorenzo Stoakes removd vmf_insert_mixed_prot(), which was added for DRM, but DRM doesn't use it any more. - Lorenzo has also coverted read_kcore() and vread() to use iterators and has thereby removed the use of bounce buffers in some cases. - Lorenzo has also contributed further cleanups of vma_merge(). - Chaitanya Prakash provides some fixes to the mmap selftesting code. - Matthew Wilcox changes xfs and afs so they no longer take sleeping locks in ->map_page(), a step towards RCUification of pagefaults. - Suren Baghdasaryan has improved mmap_lock scalability by switching to per-VMA locking. - Frederic Weisbecker has reworked the percpu cache draining so that it no longer causes latency glitches on cpu isolated workloads. - Mike Rapoport cleans up and corrects the ARCH_FORCE_MAX_ORDER Kconfig logic. - Liu Shixin has changed zswap's initialization so we no longer waste a chunk of memory if zswap is not being used. - Yosry Ahmed has improved the performance of memcg statistics flushing. - David Stevens has fixed several issues involving khugepaged, userfaultfd and shmem. - Christoph Hellwig has provided some cleanup work to zram's IO-related code paths. - David Hildenbrand has fixed up some issues in the selftest code's testing of our pte state changing. - Pankaj Raghav has made page_endio() unneeded and has removed it. - Peter Xu contributed some rationalizations of the userfaultfd selftests. - Yosry Ahmed has fixed an issue around memcg's page recalim accounting. - Chaitanya Prakash has fixed some arm-related issues in the selftests/mm code. - Longlong Xia has improved the way in which KSM handles hwpoisoned pages. - Peter Xu fixes a few issues with uffd-wp at fork() time. - Stefan Roesch has changed KSM so that it may now be used on a per-process and per-cgroup basis. * tag 'mm-stable-2023-04-27-15-30' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (369 commits) mm,unmap: avoid flushing TLB in batch if PTE is inaccessible shmem: restrict noswap option to initial user namespace mm/khugepaged: fix conflicting mods to collapse_file() sparse: remove unnecessary 0 values from rc mm: move 'mmap_min_addr' logic from callers into vm_unmapped_area() hugetlb: pte_alloc_huge() to replace huge pte_alloc_map() maple_tree: fix allocation in mas_sparse_area() mm: do not increment pgfault stats when page fault handler retries zsmalloc: allow only one active pool compaction context selftests/mm: add new selftests for KSM mm: add new KSM process and sysfs knobs mm: add new api to enable ksm per process mm: shrinkers: fix debugfs file permissions mm: don't check VMA write permissions if the PTE/PMD indicates write permissions migrate_pages_batch: fix statistics for longterm pin retry userfaultfd: use helper function range_in_vma() lib/show_mem.c: use for_each_populated_zone() simplify code mm: correct arg in reclaim_pages()/reclaim_clean_pages_from_list() fs/buffer: convert create_page_buffers to folio_create_buffers fs/buffer: add folio_create_empty_buffers helper ...
* | ext4: Use a folio in ext4_read_merkle_tree_pageMatthew Wilcox2023-04-061-7/+7
| | | | | | | | | | | | | | | | | | | | This is an implementation of fsverity_operations read_merkle_tree_page, so it must still return the precise page asked for, but we can use the folio API to reduce the number of conversions between folios & pages. Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Link: https://lore.kernel.org/r/20230324180129.1220691-30-willy@infradead.org Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* | ext4: Convert pagecache_read() to use a folioMatthew Wilcox2023-04-061-9/+7
|/ | | | | | | | Use the folio API and support folios of arbitrary sizes. Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Link: https://lore.kernel.org/r/20230324180129.1220691-29-willy@infradead.org Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* fsverity: pass pos and size to ->write_merkle_tree_blockEric Biggers2023-01-011-3/+3
| | | | | | | | | | | | | | | fsverity_operations::write_merkle_tree_block is passed the index of the block to write and the log base 2 of the block size. However, all implementations of it use these parameters only to calculate the position and the size of the block, in bytes. Therefore, make ->write_merkle_tree_block take 'pos' and 'size' parameters instead of 'index' and 'log_blocksize'. Suggested-by: Dave Chinner <david@fromorbit.com> Signed-off-by: Eric Biggers <ebiggers@google.com> Acked-by: Dave Chinner <dchinner@redhat.com> Link: https://lore.kernel.org/r/20221214224304.145712-5-ebiggers@kernel.org
* fs: ext4: initialize fsdata in pagecache_write()Alexander Potapenko2022-12-081-1/+1
| | | | | | | | | | | | | | | | When aops->write_begin() does not initialize fsdata, KMSAN reports an error passing the latter to aops->write_end(). Fix this by unconditionally initializing fsdata. Cc: Eric Biggers <ebiggers@kernel.org> Fixes: c93d8f885809 ("ext4: add basic fs-verity support") Reported-by: syzbot+9767be679ef5016b6082@syzkaller.appspotmail.com Signed-off-by: Alexander Potapenko <glider@google.com> Reviewed-by: Eric Biggers <ebiggers@google.com> Link: https://lore.kernel.org/r/20221121112134.407362-1-glider@google.com Signed-off-by: Theodore Ts'o <tytso@mit.edu> Cc: stable@kernel.org
* Merge tag 'mm-stable-2022-10-13' of ↵Linus Torvalds2022-10-141-1/+2
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Pull more MM updates from Andrew Morton: - fix a race which causes page refcounting errors in ZONE_DEVICE pages (Alistair Popple) - fix userfaultfd test harness instability (Peter Xu) - various other patches in MM, mainly fixes * tag 'mm-stable-2022-10-13' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (29 commits) highmem: fix kmap_to_page() for kmap_local_page() addresses mm/page_alloc: fix incorrect PGFREE and PGALLOC for high-order page mm/selftest: uffd: explain the write missing fault check mm/hugetlb: use hugetlb_pte_stable in migration race check mm/hugetlb: fix race condition of uffd missing/minor handling zram: always expose rw_page LoongArch: update local TLB if PTE entry exists mm: use update_mmu_tlb() on the second thread kasan: fix array-bounds warnings in tests hmm-tests: add test for migrate_device_range() nouveau/dmem: evict device private memory during release nouveau/dmem: refactor nouveau_dmem_fault_copy_one() mm/migrate_device.c: add migrate_device_range() mm/migrate_device.c: refactor migrate_vma and migrate_deivce_coherent_page() mm/memremap.c: take a pgmap reference on page allocation mm: free device private pages have zero refcount mm/memory.c: fix race when faulting a device private page mm/damon: use damon_sz_region() in appropriate place mm/damon: move sz_damon_region to damon_sz_region lib/test_meminit: add checks for the allocation functions ...
| * ext4,f2fs: fix readahead of verity dataMatthew Wilcox (Oracle)2022-10-121-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | The recent change of page_cache_ra_unbounded() arguments was buggy in the two callers, causing us to readahead the wrong pages. Move the definition of ractl down to after the index is set correctly. This affected performance on configurations that use fs-verity. Link: https://lkml.kernel.org/r/20221012193419.1453558-1-willy@infradead.org Fixes: 73bb49da50cd ("mm/readahead: make page_cache_ra_unbounded take a readahead_control") Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reported-by: Jintao Yin <nicememory@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* | ext4: factor out ext4_free_ext_path()Ye Bin2022-09-301-4/+2
|/ | | | | | | | | | Factor out ext4_free_ext_path() to free extent path. As after previous patch 'ext4_ext_drop_refs()' is only used in 'extents.c', so make it static. Signed-off-by: Ye Bin <yebin10@huawei.com> Reviewed-by: Jan Kara <jack@suse.cz> Link: https://lore.kernel.org/r/20220924021211.3831551-3-yebin10@huawei.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* ext4: Call aops write_begin() and write_end() directlyMatthew Wilcox (Oracle)2022-05-081-4/+5
| | | | | | | | pagecache_write_begin() and pagecache_write_end() are now trivial wrappers, so call the aops directly. Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Christoph Hellwig <hch@lst.de>
* Merge tag 'ext4_for_linus' of ↵Linus Torvalds2021-04-301-8/+2
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4 Pull ext4 updates from Ted Ts'o: "New features for ext4 this cycle include support for encrypted casefold, ensure that deleted file names are cleared in directory blocks by zeroing directory entries when they are unlinked or moved as part of a hash tree node split. We also improve the block allocator's performance on a freshly mounted file system by prefetching block bitmaps. There are also the usual cleanups and bug fixes, including fixing a page cache invalidation race when there is mixed buffered and direct I/O and the block size is less than page size, and allow the dax flag to be set and cleared on inline directories" * tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (32 commits) ext4: wipe ext4_dir_entry2 upon file deletion ext4: Fix occasional generic/418 failure fs: fix reporting supported extra file attributes for statx() ext4: allow the dax flag to be set and cleared on inline directories ext4: fix debug format string warning ext4: fix trailing whitespace ext4: fix various seppling typos ext4: fix error return code in ext4_fc_perform_commit() ext4: annotate data race in jbd2_journal_dirty_metadata() ext4: annotate data race in start_this_handle() ext4: fix ext4_error_err save negative errno into superblock ext4: fix error code in ext4_commit_super ext4: always panic when errors=panic is specified ext4: delete redundant uptodate check for buffer ext4: do not set SB_ACTIVE in ext4_orphan_cleanup() ext4: make prefetch_block_bitmaps default ext4: add proc files to monitor new structures ext4: improve cr 0 / cr 1 group scanning ext4: add MB_NUM_ORDERS macro ext4: add mballoc stats proc file ...
| * ext4: use memcpy_to_page() in pagecache_write()Chaitanya Kulkarni2021-03-251-4/+1
| | | | | | | | | | | | Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> Link: https://lore.kernel.org/r/20210207190425.38107-7-chaitanya.kulkarni@wdc.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
| * ext4: use memcpy_from_page() in pagecache_read()Chaitanya Kulkarni2021-03-251-4/+1
| | | | | | | | | | | | Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> Link: https://lore.kernel.org/r/20210207190425.38107-6-chaitanya.kulkarni@wdc.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* | mm/filemap: Pass the file_ra_state in the ractlMatthew Wilcox (Oracle)2021-04-231-1/+1
|/ | | | | | | | | | | | | | For readahead_expand(), we need to modify the file ra_state, so pass it down by adding it to the ractl. We have to do this because it's not always the same as f_ra in the struct file that is already being passed. Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: David Howells <dhowells@redhat.com> Tested-by: Jeff Layton <jlayton@kernel.org> Tested-by: Dave Wysochanski <dwysocha@redhat.com> Tested-By: Marc Dionne <marc.dionne@auristor.com> Link: https://lore.kernel.org/r/20210407201857.3582797-2-willy@infradead.org/ Link: https://lore.kernel.org/r/161789067431.6155.8063840447229665720.stgit@warthog.procyon.org.uk/ # v6
* ext4: fix error handling in ext4_end_enable_verity()Eric Biggers2021-03-111-34/+55
| | | | | | | | | | | | | | | | | | | | | | ext4 didn't properly clean up if verity failed to be enabled on a file: - It left verity metadata (pages past EOF) in the page cache, which would be exposed to userspace if the file was later extended. - It didn't truncate the verity metadata at all (either from cache or from disk) if an error occurred while setting the verity bit. Fix these bugs by adding a call to truncate_inode_pages() and ensuring that we truncate the verity metadata (both from cache and from disk) in all error paths. Also rework the code to cleanly separate the success path from the error paths, which makes it much easier to understand. Reported-by: Yunlei He <heyunlei@hihonor.com> Fixes: c93d8f885809 ("ext4: add basic fs-verity support") Cc: stable@vger.kernel.org # v5.4+ Signed-off-by: Eric Biggers <ebiggers@google.com> Link: https://lore.kernel.org/r/20210302200420.137977-2-ebiggers@kernel.org Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* mm/readahead: make page_cache_ra_unbounded take a readahead_controlMatthew Wilcox (Oracle)2020-10-161-2/+2
| | | | | | | | | | | Define it in the callers instead of in page_cache_ra_unbounded(). Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: David Howells <dhowells@redhat.com> Cc: Eric Biggers <ebiggers@google.com> Link: https://lkml.kernel.org/r/20200903140844.14194-4-willy@infradead.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge tag 'ext4-for-linus-5.8-rc1-2' of ↵Linus Torvalds2020-06-151-1/+4
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4 Pull more ext4 updates from Ted Ts'o: "This is the second round of ext4 commits for 5.8 merge window [1]. It includes the per-inode DAX support, which was dependant on the DAX infrastructure which came in via the XFS tree, and a number of regression and bug fixes; most notably the "BUG: using smp_processor_id() in preemptible code in ext4_mb_new_blocks" reported by syzkaller" [1] The pull request actually came in 15 minutes after I had tagged the rc1 release. Tssk, tssk, late.. - Linus * tag 'ext4-for-linus-5.8-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: ext4, jbd2: ensure panic by fix a race between jbd2 abort and ext4 error handlers ext4: support xattr gnu.* namespace for the Hurd ext4: mballoc: Use this_cpu_read instead of this_cpu_ptr ext4: avoid utf8_strncasecmp() with unstable name ext4: stop overwrite the errcode in ext4_setup_super ext4: fix partial cluster initialization when splitting extent ext4: avoid race conditions when remounting with options that change dax Documentation/dax: Update DAX enablement for ext4 fs/ext4: Introduce DAX inode flag fs/ext4: Remove jflag variable fs/ext4: Make DAX mount option a tri-state fs/ext4: Only change S_DAX on inode load fs/ext4: Update ext4_should_use_dax() fs/ext4: Change EXT4_MOUNT_DAX to EXT4_MOUNT_DAX_ALWAYS fs/ext4: Disallow verity if inode is DAX fs/ext4: Narrow scope of DAX check in setflags
| * fs/ext4: Introduce DAX inode flagIra Weiny2020-05-281-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add a flag ([EXT4|FS]_DAX_FL) to preserve FS_XFLAG_DAX in the ext4 inode. Set the flag to be user visible and changeable. Set the flag to be inherited. Allow applications to change the flag at any time except if it conflicts with the set of mutually exclusive flags (Currently VERITY, ENCRYPT, JOURNAL_DATA). Furthermore, restrict setting any of the exclusive flags if DAX is set. While conceptually possible, we do not allow setting EXT4_DAX_FL while at the same time clearing exclusion flags (or vice versa) for 2 reasons: 1) The DAX flag does not take effect immediately which introduces quite a bit of complexity 2) There is no clear use case for being this flexible Finally, on regular files, flag the inode to not be cached to facilitate changing S_DAX on the next creation of the inode. Signed-off-by: Ira Weiny <ira.weiny@intel.com> Link: https://lore.kernel.org/r/20200528150003.828793-9-ira.weiny@intel.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
| * fs/ext4: Only change S_DAX on inode loadIra Weiny2020-05-281-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | To prevent complications with in memory inodes we only set S_DAX on inode load. FS_XFLAG_DAX can be changed at any time and S_DAX will change after inode eviction and reload. Add init bool to ext4_set_inode_flags() to indicate if the inode is being newly initialized. Assert that S_DAX is not set on an inode which is just being loaded. Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Ira Weiny <ira.weiny@intel.com> Link: https://lore.kernel.org/r/20200528150003.828793-6-ira.weiny@intel.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
| * fs/ext4: Disallow verity if inode is DAXIra Weiny2020-05-281-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Verity and DAX are incompatible. Changing the DAX mode due to a verity flag change is wrong without a corresponding address_space_operations update. Make the 2 options mutually exclusive by returning an error if DAX was set first. (Setting DAX is already disabled if Verity is set first.) Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Ira Weiny <ira.weiny@intel.com> Link: https://lore.kernel.org/r/20200528150003.828793-3-ira.weiny@intel.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* | mm: add page_cache_readahead_unboundedMatthew Wilcox (Oracle)2020-06-021-33/+2
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | ext4 and f2fs have duplicated the guts of the readahead code so they can read past i_size. Instead, separate out the guts of the readahead code so they can call it directly. Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Tested-by: Eric Biggers <ebiggers@google.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: William Kucharski <william.kucharski@oracle.com> Reviewed-by: Eric Biggers <ebiggers@google.com> Cc: Chao Yu <yuchao0@huawei.com> Cc: Cong Wang <xiyou.wangcong@gmail.com> Cc: Darrick J. Wong <darrick.wong@oracle.com> Cc: Dave Chinner <dchinner@redhat.com> Cc: Gao Xiang <gaoxiang25@huawei.com> Cc: Jaegeuk Kim <jaegeuk@kernel.org> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Joseph Qi <joseph.qi@linux.alibaba.com> Cc: Junxiao Bi <junxiao.bi@oracle.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Zi Yan <ziy@nvidia.com> Cc: Johannes Thumshirn <johannes.thumshirn@wdc.com> Cc: Miklos Szeredi <mszeredi@redhat.com> Link: http://lkml.kernel.org/r/20200414150233.24495-14-willy@infradead.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* fs-verity: implement readahead of Merkle tree pagesEric Biggers2020-01-141-2/+45
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When fs-verity verifies data pages, currently it reads each Merkle tree page synchronously using read_mapping_page(). Therefore, when the Merkle tree pages aren't already cached, fs-verity causes an extra 4 KiB I/O request for every 512 KiB of data (assuming that the Merkle tree uses SHA-256 and 4 KiB blocks). This results in more I/O requests and performance loss than is strictly necessary. Therefore, implement readahead of the Merkle tree pages. For simplicity, we take advantage of the fact that the kernel already does readahead of the file's *data*, just like it does for any other file. Due to this, we don't really need a separate readahead state (struct file_ra_state) just for the Merkle tree, but rather we just need to piggy-back on the existing data readahead requests. We also only really need to bother with the first level of the Merkle tree, since the usual fan-out factor is 128, so normally over 99% of Merkle tree I/O requests are for the first level. Therefore, make fsverity_verify_bio() enable readahead of the first Merkle tree level, for up to 1/4 the number of pages in the bio, when it sees that the REQ_RAHEAD flag is set on the bio. The readahead size is then passed down to ->read_merkle_tree_page() for the filesystem to (optionally) implement if it sees that the requested page is uncached. While we're at it, also make build_merkle_tree_level() set the Merkle tree readahead size, since it's easy to do there. However, for now don't set the readahead size in fsverity_verify_page(), since currently it's only used to verify holes on ext4 and f2fs, and it would need parameters added to know how much to read ahead. This patch significantly improves fs-verity sequential read performance. Some quick benchmarks with 'cat'-ing a 250MB file after dropping caches: On an ARM64 phone (using sha256-ce): Before: 217 MB/s After: 263 MB/s (compare to sha256sum of non-verity file: 357 MB/s) In an x86_64 VM (using sha256-avx2): Before: 173 MB/s After: 215 MB/s (compare to sha256sum of non-verity file: 223 MB/s) Link: https://lore.kernel.org/r/20200106205533.137005-1-ebiggers@kernel.org Reviewed-by: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Eric Biggers <ebiggers@google.com>
* ext4: add basic fs-verity supportEric Biggers2019-08-121-0/+367
Add most of fs-verity support to ext4. fs-verity is a filesystem feature that enables transparent integrity protection and authentication of read-only files. It uses a dm-verity like mechanism at the file level: a Merkle tree is used to verify any block in the file in log(filesize) time. It is implemented mainly by helper functions in fs/verity/. See Documentation/filesystems/fsverity.rst for the full documentation. This commit adds all of ext4 fs-verity support except for the actual data verification, including: - Adding a filesystem feature flag and an inode flag for fs-verity. - Implementing the fsverity_operations to support enabling verity on an inode and reading/writing the verity metadata. - Updating ->write_begin(), ->write_end(), and ->writepages() to support writing verity metadata pages. - Calling the fs-verity hooks for ->open(), ->setattr(), and ->ioctl(). ext4 stores the verity metadata (Merkle tree and fsverity_descriptor) past the end of the file, starting at the first 64K boundary beyond i_size. This approach works because (a) verity files are readonly, and (b) pages fully beyond i_size aren't visible to userspace but can be read/written internally by ext4 with only some relatively small changes to ext4. This approach avoids having to depend on the EA_INODE feature and on rearchitecturing ext4's xattr support to support paging multi-gigabyte xattrs into memory, and to support encrypting xattrs. Note that the verity metadata *must* be encrypted when the file is, since it contains hashes of the plaintext data. This patch incorporates work by Theodore Ts'o and Chandan Rajendra. Reviewed-by: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Eric Biggers <ebiggers@google.com>