Messages in this thread | | | Date | Fri, 2 Jan 2009 18:27:57 +0000 | From | Al Viro <> | Subject | Re: [xfs-masters] RFC: Fix f_flags races without the BKL |
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On Mon, Dec 29, 2008 at 01:50:50PM +0100, Christoph Hellwig wrote: > On Mon, Dec 29, 2008 at 04:13:52AM -0700, Jonathan Corbet wrote: > > Accesses to the f_flags field have always involved a read-modify-write > > operation, and have always been racy in the absence of the BKL. The recent > > BKL-removal work made this problem worse, but it has been there for a very > > long time. The race is quite small, and, arguably, has never affected > > anybody, but it's still worth fixing. > > > > After pondering for a while, I couldn't come up with anything better than a > > global file->f_flags mutex. There's no point in bloating struct file with > > a mutex just for this purpose; it's hard to imagine that there will be any > > real contention for this lock. > > What speaks against having on in fs_struct so that it's at least not > globally serialized?
WTF? References to struct file can be shared by tasks with different associated fs_struct; how the devil can that ever work?
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