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| author |   Eric Biggers <ebiggers@google.com> | 2019-12-26 09:42:16 -0600 |
|---|---|---|
| committer |   Theodore Ts'o <tytso@mit.edu> | 2020-01-17 16:24:53 -0500 |
| commit | 457b1e353c739af39159269723949f315320446c (patch) | |
| tree | ec525088a9681a576df030b7871b423bdda07bd4 /fs/ext4 | |
| parent | ext4: handle decryption error in __ext4_block_zero_page_range() (diff) | |
| download | linux-dev-457b1e353c739af39159269723949f315320446c.tar.xz linux-dev-457b1e353c739af39159269723949f315320446c.zip | |
ext4: allow ZERO_RANGE on encrypted files
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>
Link: https://lore.kernel.org/r/20191226154216.4808-1-ebiggers@kernel.org
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Diffstat (limited to 'fs/ext4')
| -rw-r--r-- | fs/ext4/extents.c | 7 |
1 files changed, 1 insertions, 6 deletions
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c index a7f90470b1dc..4ba8215fa288 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -4891,14 +4891,9 @@ 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 */ |