On 10/22/2010 05:12 AM, Lukas Czerner wrote:
On Thu, 21 Oct 2010, Andreas Dilger wrote:
On 2010-10-21, at 08:15, Lukas Czerner wrote:
In Pass 5 when we are checking block and inode bitmaps we have great
opportunity to discard free space and unused inodes on the device,
because bitmaps has just been verified as valid. This commit takes
advantage of this opportunity and discards both, all free space and
unused inodes.
I have added new option '-K' which when set, disables discard. Also when
the underlying device does not support discard, or BLKDISCARD ioctl
returns any kind of error, or when some errors occurred in bitmaps, the
discard is disabled.
I'm always a bit nervous with patches like this, that will prevent data recovery after an e2fsck run (which seems like the opposite of what we want from e2fsck).
Two suggestions:
- it probably makes sense to disable this by default, and allow it to be
specified on the command-line and e2fsck.conf
- should we really have a short option, or a "-E discard" and "-E nodiscard"
options, which allow us to change the default easily at some later time
(which we can't do with a single -K flag)
Right, I agree it would be probably better to disable this by default.
If we do disable it by default, I think that we might also want to be consistent
and disable the discard support in mkfs by default as well?
thanks!
Ric
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