Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley
        Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United
        Kingdom.
        Registered in England and Wales under Company Registration No. 3798903
Subject: [PATCH v2 16/67] fscache: Add a function for a cache backend to note
 an I/O error
From:   David Howells <dhowells@redhat.com>
To:     linux-cachefs@redhat.com
Cc:     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:   Thu, 09 Dec 2021 16:56:53 +0000
Message-ID: <163906901316.143852.15225412215771586528.stgit@warthog.procyon.org.uk>
In-Reply-To: <163906878733.143852.5604115678965006622.stgit@warthog.procyon.org.uk>
References: <163906878733.143852.5604115678965006622.stgit@warthog.procyon.org.uk>
User-Agent: StGit/0.23
MIME-Version: 1.0
Content-Type: text/plain; charset="utf-8"
Content-Transfer-Encoding: 7bit
Precedence: bulk

Add a function to the backend API to note an I/O error in a cache.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/163819598741.215744.891281275151382095.stgit@warthog.procyon.org.uk/ # v1
---

 fs/fscache/cache.c            |   20 ++++++++++++++++++++
 include/linux/fscache-cache.h |    2 ++
 2 files changed, 22 insertions(+)

diff --git a/fs/fscache/cache.c b/fs/fscache/cache.c
index bbd102be91c4..25eac61f1c29 100644
--- a/fs/fscache/cache.c
+++ b/fs/fscache/cache.c
@@ -321,6 +321,26 @@ void fscache_end_cache_access(struct fscache_cache *cache, enum fscache_access_t
 		wake_up_var(&cache->n_accesses);
 }
 
+/**
+ * fscache_io_error - Note a cache I/O error
+ * @cache: The record describing the cache
+ *
+ * Note that an I/O error occurred in a cache and that it should no longer be
+ * used for anything.  This also reports the error into the kernel log.
+ *
+ * See Documentation/filesystems/caching/backend-api.rst for a complete
+ * description.
+ */
+void fscache_io_error(struct fscache_cache *cache)
+{
+	if (fscache_set_cache_state_maybe(cache,
+					  FSCACHE_CACHE_IS_ACTIVE,
+					  FSCACHE_CACHE_GOT_IOERROR))
+		pr_err("Cache '%s' stopped due to I/O error\n",
+		       cache->name);
+}
+EXPORT_SYMBOL(fscache_io_error);
+
 /**
  * fscache_withdraw_cache - Withdraw a cache from the active service
  * @cache: The cache cookie
diff --git a/include/linux/fscache-cache.h b/include/linux/fscache-cache.h
index a10b66ca3544..936ef731bbc7 100644
--- a/include/linux/fscache-cache.h
+++ b/include/linux/fscache-cache.h
@@ -73,6 +73,8 @@ extern int fscache_add_cache(struct fscache_cache *cache,
 extern void fscache_withdraw_cache(struct fscache_cache *cache);
 extern void fscache_withdraw_volume(struct fscache_volume *volume);
 
+extern void fscache_io_error(struct fscache_cache *cache);
+
 extern void fscache_end_volume_access(struct fscache_volume *volume,
 				      struct fscache_cookie *cookie,
 				      enum fscache_access_trace why);