Greg Freemyer wrote:
On Fri, Oct 30, 2009 at 4:22 AM, <bugzilla-daemon@xxxxxxxxxxxxxxxxxxx> wrote:
http://bugzilla.kernel.org/show_bug.cgi?id=14354
--- Comment #152 from Alexey Fisher <bug-track@xxxxxxxxxxxxxxxxx> 2009-10-30 08:22:10 ---
Ted,
Thank you for explanation :)
Notice: i learning computer forensic, and was trained to mount all evidence
systems with "-o ro" to not contaminate it. It seems like ext4 break this
tradition, so many forensics will surprised why md5sum do not match.
Ted, (Alexey there is a response to further down).
I have not followed this thread ultra-closely but Alexey's comment got
my attention.
Ignoring computer forensics, with LVM snapshots, hardware raid array
snapshots, etc. even in the presence of a dirty log, we need to be
able to mount a drive in true read-only fashion fro many backup
operations to function correctly.
XFS added an extra mount flag for that 5 or so years ago.
I hope ext4 either has or will add a true read-only mount option.
Maybe Eric Sandeen remembers the actual drivers for adding that
feature to XFS.
After a little brief digging I'm not sure when the xfs mount option went
in or why...
But for both
xfs: mount -o ro,norecovery
and
ext[34]: mount -o ro,noload
I don't think either one should touch the disk.
Also, both should skip journal replay if you set the block device
readonly prior to mount (hdparm -r can do this).
-Eric
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