| Message ID | 20191226154216.4808-1-ebiggers@kernel.org (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
| Series | ext4: allow ZERO_RANGE on encrypted files | expand |
On Thu, Dec 26, 2019 at 09:42:16AM -0600, Eric Biggers wrote: > From: Eric Biggers <ebiggers@google.com> > > When ext4 encryption support was first added, ZERO_RANGE was disallowed, > supposedly because test failures (e.g. ext4/001) were seen when enabling > it, and at the time there wasn't enough time/interest to debug it. > > However, there's actually no reason why ZERO_RANGE can't work on > encrypted files. And it fact it *does* work now. Whole blocks in the > zeroed range are converted to unwritten extents, as usual; encryption > makes no difference for that part. Partial blocks are zeroed in the > pagecache and then ->writepages() encrypts those blocks as usual. > ext4_block_zero_page_range() handles reading and decrypting the block if > needed before actually doing the pagecache write. > > Also, f2fs has always supported ZERO_RANGE on encrypted files. > > As far as I can tell, the reason that ext4/001 was failing in v4.1 was > actually because of one of the bugs fixed by commit 36086d43f657 ("ext4 > crypto: fix bugs in ext4_encrypted_zeroout()"). The bug made > ext4_encrypted_zeroout() always return a positive value, which caused > unwritten extents in encrypted files to sometimes not be marked as > initialized after being written to. This bug was not actually in > ZERO_RANGE; it just happened to trigger during the extents manipulation > done in ext4/001 (and probably other tests too). > > So, let's enable ZERO_RANGE on encrypted files on ext4. > > Tested with: > gce-xfstests -c ext4/encrypt -g auto > gce-xfstests -c ext4/encrypt_1k -g auto > > Got the same set of test failures both with and without this patch. > But with this patch 6 fewer tests are skipped: ext4/001, generic/008, > generic/009, generic/033, generic/096, and generic/511. > > Signed-off-by: Eric Biggers <ebiggers@google.com> Thanks, applied. - Ted
diff --git a/Documentation/filesystems/fscrypt.rst b/Documentation/filesystems/fscrypt.rst index 68c2bc8275cf..07f1f15276bf 100644 --- a/Documentation/filesystems/fscrypt.rst +++ b/Documentation/filesystems/fscrypt.rst @@ -975,9 +975,9 @@ astute users may notice some differences in behavior: - Direct I/O is not supported on encrypted files. Attempts to use direct I/O on such files will fall back to buffered I/O. -- The fallocate operations FALLOC_FL_COLLAPSE_RANGE, - FALLOC_FL_INSERT_RANGE, and FALLOC_FL_ZERO_RANGE are not supported - on encrypted files and will fail with EOPNOTSUPP. +- The fallocate operations FALLOC_FL_COLLAPSE_RANGE and + FALLOC_FL_INSERT_RANGE are not supported on encrypted files and will + fail with EOPNOTSUPP. - Online defragmentation of encrypted files is not supported. The EXT4_IOC_MOVE_EXT and F2FS_IOC_MOVE_RANGE ioctls will fail with diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c index 0e8708b77da6..dae66e8f0c3a 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -4890,14 +4890,9 @@ long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len) * range since we would need to re-encrypt blocks with a * different IV or XTS tweak (which are based on the logical * block number). - * - * XXX It's not clear why zero range isn't working, but we'll - * leave it disabled for encrypted inodes for now. This is a - * bug we should fix.... */ if (IS_ENCRYPTED(inode) && - (mode & (FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_INSERT_RANGE | - FALLOC_FL_ZERO_RANGE))) + (mode & (FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_INSERT_RANGE))) return -EOPNOTSUPP; /* Return error if mode is not supported */