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Wong" Cc: linux-xfs@vger.kernel.org, Christoph Hellwig , Dave Chinner Subject: Re: [RFC PATCH] xfs: use log_incompat feature instead of speculate matching Message-ID: <20200824154120.GA23868@xiangao.remote.csb> References: <20200823172421.GA16579@xiangao.remote.csb> <20200824081900.27573-1-hsiangkao@aol.com> <20200824083402.GB16579@xiangao.remote.csb> <20200824150832.GV6096@magnolia> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200824150832.GV6096@magnolia> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-xfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org On Mon, Aug 24, 2020 at 08:08:32AM -0700, Darrick J. Wong wrote: > On Mon, Aug 24, 2020 at 04:34:02PM +0800, Gao Xiang wrote: > > On Mon, Aug 24, 2020 at 04:19:00PM +0800, Gao Xiang wrote: > > > From: Gao Xiang > > > > > > Use a log_incompat feature just to be safe. > > > If the current mount is in RO state, it will defer > > > to next RW remount. > > > > > > Signed-off-by: Gao Xiang > > > --- > > > > > > After some careful thinking, I think it's probably not working for > > > supported V4 XFS filesystem. So, I think we'd probably insist on the > > > previous way (correct me if I'm wrong)... > > > > > > (since xfs_sb_to_disk() refuses to set up any feature bits for non V5 > > > fses. That is another awkward setting here (doesn't write out/check > > > feature bits for V4 even though using V4 sb reserved fields) and > > > unless let V4 completely RO since this commit. ) > > > > > > Just send out as a RFC patch. Not fully tested after I thought as above. > > > > Unless we also use sb_features2 for V4 filesystem to entirely > > refuse to mount such V4 filesystem... > > Some more opinions on this? > > Frankly, V4 is pretty old, so I wouldn't bother. We only build new > features for V5 format. Okay, let me go further with log_incompat (v5) and sb_features2 (v4) later. Thanks, Gao Xiang > > --D > > > Thanks, > > Gao Xiang > > >