From 324b954ac80cff0d11ddb6bde9b6631e45e98620 Mon Sep 17 00:00:00 2001 From: Jeffle Xu Date: Mon, 25 Apr 2022 20:21:26 +0800 Subject: cachefiles: notify the user daemon when withdrawing cookie Notify the user daemon that cookie is going to be withdrawn, providing a hint that the associated anonymous fd can be closed. Be noted that this is only a hint. The user daemon may close the associated anonymous fd when receiving the CLOSE request, then it will receive another anonymous fd when the cookie gets looked up. Or it may ignore the CLOSE request, and keep writing data through the anonymous fd. However the next time the cookie gets looked up, the user daemon will still receive another new anonymous fd. Signed-off-by: Jeffle Xu Acked-by: David Howells Link: https://lore.kernel.org/r/20220425122143.56815-5-jefflexu@linux.alibaba.com Signed-off-by: Gao Xiang --- fs/cachefiles/ondemand.c | 38 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 38 insertions(+) (limited to 'fs/cachefiles/ondemand.c') diff --git a/fs/cachefiles/ondemand.c b/fs/cachefiles/ondemand.c index 7946ee6c40be..11b1c15ac697 100644 --- a/fs/cachefiles/ondemand.c +++ b/fs/cachefiles/ondemand.c @@ -229,6 +229,12 @@ ssize_t cachefiles_ondemand_daemon_read(struct cachefiles_cache *cache, goto err_put_fd; } + /* CLOSE request has no reply */ + if (msg->opcode == CACHEFILES_OP_CLOSE) { + xa_erase(&cache->reqs, id); + complete(&req->done); + } + return n; err_put_fd: @@ -300,6 +306,13 @@ static int cachefiles_ondemand_send_req(struct cachefiles_object *object, /* coupled with the barrier in cachefiles_flush_reqs() */ smp_mb(); + if (opcode != CACHEFILES_OP_OPEN && object->ondemand_id <= 0) { + WARN_ON_ONCE(object->ondemand_id == 0); + xas_unlock(&xas); + ret = -EIO; + goto out; + } + xas.xa_index = 0; xas_find_marked(&xas, UINT_MAX, XA_FREE_MARK); if (xas.xa_node == XAS_RESTART) @@ -356,6 +369,25 @@ static int cachefiles_ondemand_init_open_req(struct cachefiles_req *req, return 0; } +static int cachefiles_ondemand_init_close_req(struct cachefiles_req *req, + void *private) +{ + struct cachefiles_object *object = req->object; + int object_id = object->ondemand_id; + + /* + * It's possible that object id is still 0 if the cookie looking up + * phase failed before OPEN request has ever been sent. Also avoid + * sending CLOSE request for CACHEFILES_ONDEMAND_ID_CLOSED, which means + * anon_fd has already been closed. + */ + if (object_id <= 0) + return -ENOENT; + + req->msg.object_id = object_id; + return 0; +} + int cachefiles_ondemand_init_object(struct cachefiles_object *object) { struct fscache_cookie *cookie = object->cookie; @@ -379,3 +411,9 @@ int cachefiles_ondemand_init_object(struct cachefiles_object *object) return cachefiles_ondemand_send_req(object, CACHEFILES_OP_OPEN, data_len, cachefiles_ondemand_init_open_req, NULL); } + +void cachefiles_ondemand_clean_object(struct cachefiles_object *object) +{ + cachefiles_ondemand_send_req(object, CACHEFILES_OP_CLOSE, 0, + cachefiles_ondemand_init_close_req, NULL); +} -- cgit v1.2.3