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cachefiles: add restore command to recover inflight ondemand read requests

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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>
Link: https://lore.kernel.org/r/20231120041422.75170-6-zhujia.zj@bytedance.com
Reviewed-by: Jingbo Xu <jefflexu@linux.alibaba.com>
Reviewed-by: David Howells <dhowells@redhat.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
This commit is contained in:
Jia Zhu 2023-11-20 12:14:22 +08:00 committed by Christian Brauner
parent b817e22b2e
commit e73fa11a35
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GPG Key ID: 91C61BC06578DCA2
3 changed files with 27 additions and 0 deletions
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1
fs/cachefiles/daemon.c
View File

@ -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 }
};

3
fs/cachefiles/internal.h
View File

@ -303,6 +303,9 @@ 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);

23
fs/cachefiles/ondemand.c
View File

@ -182,6 +182,29 @@ out:
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;