Il 27/02/2011 23:49, Ted Ts'o ha scritto: > On Mon, Feb 21, 2011 at 05:50:21PM +0100, Marco Stornelli wrote: >> 2011/2/21 Christoph Hellwig <hch@xxxxxxxxxxxxx>: >>> On Mon, Feb 21, 2011 at 09:26:32AM +0100, Marco Stornelli wrote: >>>> From: Marco Stornelli <marco.stornelli@xxxxxxxxx> >>>> >>>> All fs must check for the immutable flag in their fallocate callback. >>>> It's possible to have a race condition in this scenario: an application >>>> open a file in read/write and it does something, meanwhile root set the >>>> immutable flag on the file, the application at that point can call >>>> fallocate with success. Only Ocfs2 check for the immutable flag at the >>>> moment. >>> >>> Please add the check in fs/open.c:do_fallocate() so that it covers all >>> filesystems. >>> >>> >> >> The check should be done after the fs got the inode mutex lock. > > Why? None of the other places which check the IMMUTABLE flag do so I add to my previous response an other point: IMHO each fs should check for it because after the inclusion of punch hole patch, the fs can/cannot check for the append-only flag. So XFS (it supports the "unreserve") should check even for append. I think we don't want to allow this operation for an append-only file, isn't it? About this point I'll update and resend my patch. Marco -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
