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    Revert "ext4: Remove journal_checksum mount option and enable it by default" · d4da6c9c
    Linus Torvalds 提交于
    This reverts commit d0646f7b, as
    requested by Eric Sandeen.
    
    It can basically cause an ext4 filesystem to miss recovery (and thus get
    mounted with errors) if the journal checksum does not match.
    
    Quoth Eric:
    
       "My hand-wavy hunch about what is happening is that we're finding a
        bad checksum on the last partially-written transaction, which is
        not surprising, but if we have a wrapped log and we're doing the
        initial scan for head/tail, and we abort scanning on that bad
        checksum, then we are essentially running an unrecovered filesystem.
    
        But that's hand-wavy and I need to go look at the code.
    
        We lived without journal checksums on by default until now, and at
        this point they're doing more harm than good, so we should revert
        the default-changing commit until we can fix it and do some good
        power-fail testing with the fixes in place."
    
    See
    
    	http://bugzilla.kernel.org/show_bug.cgi?id=14354
    
    for all the gory details.
    Requested-by: NEric Sandeen <sandeen@redhat.com>
    Cc: Theodore Tso <tytso@mit.edu>
    Cc: Alexey Fisher <bug-track@fisher-privat.net>
    Cc: Maxim Levitsky <maximlevitsky@gmail.com>
    Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
    Cc: Mathias Burén <mathias.buren@gmail.com>
    Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
    d4da6c9c
ext4.h 61.2 KB