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Subject: [PATCH v4 23/68] fscache: Provide a function to let the netfs update
 its coherency data
From:   David Howells <dhowells@redhat.com>
To:     linux-cachefs@redhat.com
Cc:     Jeff Layton <jlayton@kernel.org>, dhowells@redhat.com,
        Trond Myklebust <trondmy@hammerspace.com>,
        Anna Schumaker <anna.schumaker@netapp.com>,
        Steve French <sfrench@samba.org>,
        Dominique Martinet <asmadeus@codewreck.org>,
        Jeff Layton <jlayton@kernel.org>,
        Matthew Wilcox <willy@infradead.org>,
        Alexander Viro <viro@zeniv.linux.org.uk>,
        Omar Sandoval <osandov@osandov.com>,
        JeffleXu <jefflexu@linux.alibaba.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        linux-afs@lists.infradead.org, linux-nfs@vger.kernel.org,
        linux-cifs@vger.kernel.org, ceph-devel@vger.kernel.org,
        v9fs-developer@lists.sourceforge.net,
        linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Date:   Wed, 22 Dec 2021 23:19:44 +0000
Message-ID: <164021518440.640689.6369952464473039268.stgit@warthog.procyon.org.uk>
In-Reply-To: <164021479106.640689.17404516570194656552.stgit@warthog.procyon.org.uk>
References: <164021479106.640689.17404516570194656552.stgit@warthog.procyon.org.uk>
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Provide a function to let the netfs update its coherency data:

	void fscache_update_cookie(struct fscache_cookie *cookie,
				   const void *aux_data,
				   const loff_t *object_size);

This will update the auxiliary data and/or the size of the object attached
to a cookie if either pointer is not-NULL and flag that the disk needs to
be updated.

Note that fscache_unuse_cookie() also allows this to be done.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/163819610438.215744.4223265964131424954.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/163906913530.143852.18150303220217653820.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163967117795.1823006.7493373142653442595.stgit@warthog.procyon.org.uk/ # v3
---

 include/linux/fscache.h |   22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/include/linux/fscache.h b/include/linux/fscache.h
index 7cdc63c4fe35..fc77648c8af6 100644
--- a/include/linux/fscache.h
+++ b/include/linux/fscache.h
@@ -338,6 +338,28 @@ void __fscache_update_cookie(struct fscache_cookie *cookie, const void *aux_data
 	set_bit(FSCACHE_COOKIE_NEEDS_UPDATE, &cookie->flags);
 }
 
+/**
+ * fscache_update_cookie - Request that a cache object be updated
+ * @cookie: The cookie representing the cache object
+ * @aux_data: The updated auxiliary data for the cookie (may be NULL)
+ * @object_size: The current size of the object (may be NULL)
+ *
+ * Request an update of the index data for the cache object associated with the
+ * cookie.  The auxiliary data on the cookie will be updated first if @aux_data
+ * is set and the object size will be updated and the object possibly trimmed
+ * if @object_size is set.
+ *
+ * See Documentation/filesystems/caching/netfs-api.rst for a complete
+ * description.
+ */
+static inline
+void fscache_update_cookie(struct fscache_cookie *cookie, const void *aux_data,
+			   const loff_t *object_size)
+{
+	if (fscache_cookie_enabled(cookie))
+		__fscache_update_cookie(cookie, aux_data, object_size);
+}
+
 /**
  * fscache_invalidate - Notify cache that an object needs invalidation
  * @cookie: The cookie representing the cache object