diff mbox series

[V2,5/5] cachefiles: add restore command to recover inflight ondemand read requests

Message ID 20221014030745.25748-6-zhujia.zj@bytedance.com
State New
Headers
Series Introduce daemon failover mechanism to recover from crashing |

Commit Message

Jia Zhu Oct. 14, 2022, 3:07 a.m. UTC 
  Previously, in ondemand read scenario, if the anonymous fd was closed by
user daemon, inflight and subsequent read requests would return EIO.
As long as the device connection is not released, user daemon can hold
and restore inflight requests by setting the request flag to
CACHEFILES_REQ_NEW.

Suggested-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Signed-off-by: Jia Zhu <zhujia.zj@bytedance.com>
Signed-off-by: Xin Yin <yinxin.x@bytedance.com>
---
 fs/cachefiles/daemon.c   |  1 +
 fs/cachefiles/internal.h |  3 +++
 fs/cachefiles/ondemand.c | 23 +++++++++++++++++++++++
 3 files changed, 27 insertions(+)

Comments

Jingbo Xu Oct. 14, 2022, 6:33 a.m. UTC | #1 
On 10/14/22 11:07 AM, Jia Zhu wrote:
> Previously, in ondemand read scenario, if the anonymous fd was closed by
> user daemon, inflight and subsequent read requests would return EIO.
> As long as the device connection is not released, user daemon can hold
> and restore inflight requests by setting the request flag to
> CACHEFILES_REQ_NEW.
> 
> Suggested-by: Gao Xiang <hsiangkao@linux.alibaba.com>
> Signed-off-by: Jia Zhu <zhujia.zj@bytedance.com>
> Signed-off-by: Xin Yin <yinxin.x@bytedance.com>

LGTM.

Reviewed-by: Jingbo Xu <jefflexu@linux.alibaba.com>
diff mbox series

Patch

diff --git a/fs/cachefiles/daemon.c b/fs/cachefiles/daemon.c
index c74bd1f4ecf5..014369266cb2 100644
--- a/fs/cachefiles/daemon.c
+++ b/fs/cachefiles/daemon.c
@@ -77,6 +77,7 @@  static const struct cachefiles_daemon_cmd cachefiles_daemon_cmds[] = {
 	{ "tag",	cachefiles_daemon_tag		},
 #ifdef CONFIG_CACHEFILES_ONDEMAND
 	{ "copen",	cachefiles_ondemand_copen	},
+	{ "restore",	cachefiles_ondemand_restore	},
 #endif
 	{ "",		NULL				}
 };
diff --git a/fs/cachefiles/internal.h b/fs/cachefiles/internal.h
index 98d6cf58db11..a3cacba57def 100644
--- a/fs/cachefiles/internal.h
+++ b/fs/cachefiles/internal.h
@@ -302,6 +302,9 @@  extern ssize_t cachefiles_ondemand_daemon_read(struct cachefiles_cache *cache,
 extern int cachefiles_ondemand_copen(struct cachefiles_cache *cache,
 				     char *args);
 
+extern int cachefiles_ondemand_restore(struct cachefiles_cache *cache,
+					char *args);
+
 extern int cachefiles_ondemand_init_object(struct cachefiles_object *object);
 extern void cachefiles_ondemand_clean_object(struct cachefiles_object *object);
 
diff --git a/fs/cachefiles/ondemand.c b/fs/cachefiles/ondemand.c
index c9eea89befec..08677c9d0004 100644
--- a/fs/cachefiles/ondemand.c
+++ b/fs/cachefiles/ondemand.c
@@ -182,6 +182,29 @@  int cachefiles_ondemand_copen(struct cachefiles_cache *cache, char *args)
 	return ret;
 }
 
+int cachefiles_ondemand_restore(struct cachefiles_cache *cache, char *args)
+{
+	struct cachefiles_req *req;
+
+	XA_STATE(xas, &cache->reqs, 0);
+
+	if (!test_bit(CACHEFILES_ONDEMAND_MODE, &cache->flags))
+		return -EOPNOTSUPP;
+
+	/*
+	 * Reset the requests to CACHEFILES_REQ_NEW state, so that the
+	 * requests have been processed halfway before the crash of the
+	 * user daemon could be reprocessed after the recovery.
+	 */
+	xas_lock(&xas);
+	xas_for_each(&xas, req, ULONG_MAX)
+		xas_set_mark(&xas, CACHEFILES_REQ_NEW);
+	xas_unlock(&xas);
+
+	wake_up_all(&cache->daemon_pollwq);
+	return 0;
+}
+
 static int cachefiles_ondemand_get_fd(struct cachefiles_req *req)
 {
 	struct cachefiles_object *object;