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authorSami Tolvanen <samitolvanen@google.com>2015-03-18 18:52:14 +0300
committerMike Snitzer <snitzer@redhat.com>2015-04-15 19:10:22 +0300
commit65ff5b7ddf0541f2b6e5cc59c47bfbf6cbcd91b8 (patch)
tree2a5391011a315f42e409a33d8238544451484c14 /Documentation
parent0e0e32c16cfd2eeaf4fd4f16aa6cccd1333ce1e0 (diff)
downloadlinux-65ff5b7ddf0541f2b6e5cc59c47bfbf6cbcd91b8.tar.xz
dm verity: add error handling modes for corrupted blocks
Add device specific modes to dm-verity to specify how corrupted blocks should be handled. The following modes are defined: - DM_VERITY_MODE_EIO is the default behavior, where reading a corrupted block results in -EIO. - DM_VERITY_MODE_LOGGING only logs corrupted blocks, but does not block the read. - DM_VERITY_MODE_RESTART calls kernel_restart when a corrupted block is discovered. In addition, each mode sends a uevent to notify userspace of corruption and to allow further recovery actions. The driver defaults to previous behavior (DM_VERITY_MODE_EIO) and other modes can be enabled with an additional parameter to the verity table. Signed-off-by: Sami Tolvanen <samitolvanen@google.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/device-mapper/verity.txt17
1 files changed, 17 insertions, 0 deletions
diff --git a/Documentation/device-mapper/verity.txt b/Documentation/device-mapper/verity.txt
index 9884681535ee..64ccc5a079a5 100644
--- a/Documentation/device-mapper/verity.txt
+++ b/Documentation/device-mapper/verity.txt
@@ -11,6 +11,7 @@ Construction Parameters
<data_block_size> <hash_block_size>
<num_data_blocks> <hash_start_block>
<algorithm> <digest> <salt>
+ [<#opt_params> <opt_params>]
<version>
This is the type of the on-disk hash format.
@@ -62,6 +63,22 @@ Construction Parameters
<salt>
The hexadecimal encoding of the salt value.
+<#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 ignore_corruption
+
+ignore_corruption
+ Log corrupted blocks, but allow read operations to proceed normally.
+
+restart_on_corruption
+ Restart the system when a corrupted block is discovered. This option is
+ not compatible with ignore_corruption and requires user space support to
+ avoid restart loops.
+
Theory of operation
===================