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path: root/Documentation/filesystems/ext4.txt
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2008-05-26ext4: enable barriers by defaultEric Sandeen
I can't think of any valid reason for ext4 to not use barriers when they are available; I believe this is necessary for filesystem integrity in the face of a volatile write cache on storage. An administrator who trusts that the cache is sufficiently battery- backed (and power supplies are sufficiently redundant, etc...) can always turn it back off again. SuSE has carried such a patch for ext3 for quite some time now. Also document the mount option while we're at it. Signed-off-by: Eric Sandeen <sandeen@redhat.com> Signed-off-by: Mingming Cao <cmm@us.ibm.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2008-01-29ext4: Add multi block allocator for ext4Alex Tomas
Signed-off-by: Alex Tomas <alex@clusterfs.com> Signed-off-by: Andreas Dilger <adilger@clusterfs.com> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Eric Sandeen <sandeen@redhat.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2008-01-28ext4: Add the journal checksum featureGirish Shilamkar
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>
2006-10-11[PATCH] Documentation/filesystems/ext4.txtDave Kleikamp
This file, ext4.txt, was put together with information from Andrew Morton, Andreas Dilger, Suparna Bhattacharya, and Ted Ts'o. I copied the mount options, with the exception of "extents", from ext3.txt, so if anyone is aware of anything out-of-date, please let me know. Signed-off-by: Dave Kleikamp <shaggy@austin.ibm.com> Cc: Theodore Ts'o <tytso@mit.edu> Cc: Suparna Bhattacharya <suparna@in.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>