diff options
Diffstat (limited to 'Documentation/device-mapper')
| -rw-r--r-- | Documentation/device-mapper/dm-crypt.txt | 21 |
1 files changed, 20 insertions, 1 deletions
diff --git a/Documentation/device-mapper/dm-crypt.txt b/Documentation/device-mapper/dm-crypt.txt index 6b5c42dbbe84..2c656ae43ba7 100644 --- a/Documentation/device-mapper/dm-crypt.txt +++ b/Documentation/device-mapper/dm-crypt.txt @@ -4,7 +4,8 @@ dm-crypt Device-Mapper's "crypt" target provides transparent encryption of block devices using the kernel crypto API. -Parameters: <cipher> <key> <iv_offset> <device path> <offset> +Parameters: <cipher> <key> <iv_offset> <device path> \ + <offset> [<#opt_params> <opt_params>] <cipher> Encryption cipher and an optional IV generation mode. @@ -37,6 +38,24 @@ Parameters: <cipher> <key> <iv_offset> <device path> <offset> <offset> Starting sector within the device where the encrypted data begins. +<#opt_params> + Number of optional parameters. If there are no optional parameters, + the optional paramaters section can be skipped or #opt_params can be zero. + Otherwise #opt_params is the number of following arguments. + + Example of optional parameters section: + 1 allow_discards + +allow_discards + Block discard requests (a.k.a. TRIM) are passed through the crypt device. + The default is to ignore discard requests. + + WARNING: Assess the specific security risks carefully before enabling this + option. For example, allowing discards on encrypted devices may lead to + the leak of information about the ciphertext device (filesystem type, + used space etc.) if the discarded blocks can be located easily on the + device later. + Example scripts =============== LUKS (Linux Unified Key Setup) is now the preferred way to set up disk |