-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 2/24/2012 11:13 AM, Lukas Czerner wrote: > It does not work that way, uinit is never set back. If it has been > formated without discard it is user choice, moving the image to > the thinly provisioned device, or ssd with dd is really bad idea > anyway. That said, UNINIT means that it has not been used and hence > there should be nothing to reclaim. I could have sworn that e2fsck set it back when the block group became free again, since there is once again no need to parse the bitmap and you can just assume it's empty without having to read it. I certainly have e2defrag doing this. If fsck and the kernel currently don't do this, they should. Whether it is a bad idea or not, people do move filesystems around and have existing systems formatted before mke2fs would issue discards, so it is a good idea to discard unused areas regardless of whether or not they are uninitialized. My understanding of uninitialized is that it was added as an optimization meaning "there's nothing here, so you can skip/ignore this" rather than "this has _never_ been used, so you can rely on it containing all zeros and being discarded". Indeed, a quick test filling a block device with random data and running mke2fs on it leaves the random data in the uninitialized block bitmaps rather than writing all zeros. -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.17 (MingW32) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iQEcBAEBAgAGBQJPR79fAAoJEJrBOlT6nu75K8QH/RJoNQPm+rGtmv1cmWPusuNb pb/6hRmOhsIUClaMn2diinGgH7HQbZ9FqsSx0mZmWq52T/21korGk3fyVe/nfL9m h4xFYJLNEdsSCJE7mcpUu5BMxCwlYEcybHu7xobVtqHlF671zjszj/xCGBgQIEwD 3tRu8JXc/grnrya0CxDXd5kenM6oQviEmkproYUjG21XW+2DKjgHD1w6lbcHZHw5 5fvWVwFOMy9OgagcBzAxo43E7oZoPCD6o54HT8As7FoBfUSt9Z4GLMe3ULH4SbpP KKuRiumOnBW9fz7I3jRDkVpJ+9MxWqpUL4SA79sDreYfOBAa6m7cOaR+PHr8sTM= =8u4o -----END PGP SIGNATURE----- -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
