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authorGirish Shilamkar <girish@clusterfs.com>2008-01-29 07:58:27 +0300
committerTheodore Ts'o <tytso@mit.edu>2008-01-29 07:58:27 +0300
commit818d276ceb83aa9fdebb5e0a53188290312de987 (patch)
treede3fb4ffadd72caea2876c5232ce76cd14b3646e /fs/Kconfig
parent8e85fb3f305b24b79c6d9cb7a56d22b062335ad3 (diff)
downloadlinux-818d276ceb83aa9fdebb5e0a53188290312de987.tar.xz
ext4: Add the journal checksum feature
The journal checksum feature adds two new flags i.e JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT and JBD2_FEATURE_COMPAT_CHECKSUM. JBD2_FEATURE_CHECKSUM flag indicates that the commit block contains the checksum for the blocks described by the descriptor blocks. Due to checksums, writing of the commit record no longer needs to be synchronous. Now commit record can be sent to disk without waiting for descriptor blocks to be written to disk. This behavior is controlled using JBD2_FEATURE_ASYNC_COMMIT flag. Older kernels/e2fsck should not be able to recover the journal with _ASYNC_COMMIT hence it is made incompat. The commit header has been extended to hold the checksum along with the type of the checksum. For recovery in pass scan checksums are verified to ensure the sanity and completeness(in case of _ASYNC_COMMIT) of every transaction. Signed-off-by: Andreas Dilger <adilger@clusterfs.com> Signed-off-by: Girish Shilamkar <girish@clusterfs.com> Signed-off-by: Dave Kleikamp <shaggy@linux.vnet.ibm.com> Signed-off-by: Mingming Cao <cmm@us.ibm.com>
Diffstat (limited to 'fs/Kconfig')
-rw-r--r--fs/Kconfig1
1 files changed, 1 insertions, 0 deletions
diff --git a/fs/Kconfig b/fs/Kconfig
index 9656139d2e99..219ec06a8c7e 100644
--- a/fs/Kconfig
+++ b/fs/Kconfig
@@ -236,6 +236,7 @@ config JBD_DEBUG
config JBD2
tristate
+ select CRC32
help
This is a generic journaling layer for block devices that support
both 32-bit and 64-bit block numbers. It is currently used by