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Aivazian" , David Sterba , OGAWA Hirofumi , Muchun Song , Oscar Salvador , David Hildenbrand , linux-mm@kvack.org, linux-aio@kvack.org, Benjamin LaHaise Subject: Re: [PATCH 17/32] fs: Move metadata bhs tracking to a separate struct Message-ID: References: <20260303101717.27224-1-jack@suse.cz> <20260303103406.4355-49-jack@suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260303103406.4355-49-jack@suse.cz> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html X-Rspam-User: X-Rspamd-Queue-Id: E510B40010 X-Rspamd-Server: rspam08 X-Stat-Signature: uoc5sgzgrtw7zsbfb85dhbudingbzb4b X-HE-Tag: 1772631637-624899 X-HE-Meta: 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 n2QPlls1 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Tue, Mar 03, 2026 at 11:34:06AM +0100, Jan Kara wrote: > +static void remove_assoc_queue(struct buffer_head *bh) > +{ > + struct address_space *mapping; > + struct mapping_metadata_bhs *mmb; > + > + /* > + * The locking dance is ugly here. We need to acquire lock > + * protecting metadata bh list while possibly racing with bh > + * being removed from the list or moved to a different one. We > + * use RCU to pin mapping_metadata_bhs in memory to > + * opportunistically acquire the lock and then recheck the bh > + * didn't move under us. > + */ Should the buffer_head simply have a pointer to the metadata bh list, as that would avoid all this and keep a lot of the references to the list self-contained?