xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

dm crypt: always disable discard_zeroes_data

Browse Source 
If optional discard support in dm-crypt is enabled, discards requests
bypass the crypt queue and blocks of the underlying device are discarded.
For the read path, discarded blocks are handled the same as normal
ciphertext blocks, thus decrypted.

So if the underlying device announces discarded regions return zeroes,
dm-crypt must disable this flag because after decryption there is just
random noise instead of zeroes.

Signed-off-by: Milan Broz <mbroz@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
This commit is contained in:
Milan Broz
2011-09-25 23:26:21 +01:00
committed by Alasdair G Kergon
parent 8232480944
commit 983c7db347
3 changed files with 26 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
drivers/md/dm-crypt.c
View File

@@ -1698,6 +1698,8 @@ static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
}
ti->num_flush_requests = 1;
ti->discard_zeroes_data_unsupported = 1;
return 0;
bad: