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charset=us-ascii Content-Disposition: inline In-Reply-To: <20190815145421.GN14313@quack2.suse.cz> User-Agent: Mutt/1.5.21 (2010-09-15) 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: On Thu, Aug 15, 2019 at 04:54:21PM +0200, Jan Kara wrote: > > + /* and find the associated wb */ > > + wb = wb_get_create(bdi, memcg_css, GFP_NOWAIT | __GFP_NOWARN); > > + if (!wb) { > > + ret = -ENOMEM; > > + goto out_css_put; > > + } > > One more thought: You don't want the "_create" part here, do you? If > there's any point in writing back using this wb, it must be attached to > some inode and thus it must exist. In the normal case wb_get_create() will > just fetch the reference and be done with it but when you feed garbage into > this function due to id going stale or frn structures getting corrupted due > to concurrent access, you can be creating bogus wb structures in bdi... Yeah, it can create wbs unnecessarily which isn't critical but also is easy to fix. Will update. Thanks. -- tejun