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See http://www.infradead.org/rpr.html X-Rspamd-Queue-Id: 4CBE34000D X-Stat-Signature: hitm15r1w1siykbinpztrboau5r1bani X-Rspamd-Server: rspam09 X-Rspam-User: X-HE-Tag: 1729228010-455006 X-HE-Meta: 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 g3c12mXB 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Thu, Oct 17, 2024 at 01:36:41PM -0400, Waiman Long wrote: > > At least for the XFS use case where direct I/O takes a share lock > > that needs to be replaced with an exclusive one for certain kinds of > > I/O would be useless. But then again we've survived without this > > operation for a long time, despite the initial port bringing one over > > from IRIX. > > That means XFS only needs to upgrade to a write lock in certain cases only, > not all of them. Yes. Basically when we detect a direct I/O writes needs to clear the SUID bit or other metadata, or when it is an extending write. > Right? In that case, read_try_upgrade() that attempts to > upgrade to a write lock will be useful. Yes. But I also understand Peters reasoning that it will be very hard to actually have a useful implementation that does better than just unlocking (which is what we do currently).