Messages in this thread | | | Subject | Re: [PATCH 2/2] block: create ioctl to discard-or-zeroout a range of blocks | From | Ric Wheeler <> | Date | Fri, 11 Mar 2016 10:12:13 +0530 |
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On 03/11/2016 12:03 AM, Linus Torvalds wrote: > On Thu, Mar 10, 2016 at 6:58 AM, Ric Wheeler <ricwheeler@gmail.com> wrote: >> What was objectionable at the time this patch was raised years back (not >> just to me, but to pretty much every fs developer at LSF/MM that year) >> centered on the concern that this would be viewed as a "performance" mode >> and we get pressure to support this for non-priveleged users. It gives any >> user effectively the ability to read the block device content for previously >> allocated data without restriction. > The sane way to do it would be to just check permissions of the > underlying block device. > > That way, people can just set the permissions for that to whatever > they want. If google right now uses some magical group for this, they > could make the underlying block device be writable for that group. > > We can do the security check at the filesystem level, because we have > sb->s_bdev->bd_inode, and if you have read and write permissions to > that inode, you might as well have permission to create a unsafe hole. > > That doesn't sound very hacky to me. > > Linus
I agree that this sounds quite reasonable.
Ric
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