[RFC 09/19] netfs: refactor netfs_rreq_unlock()

[Jeffle Xu]

In demand-read case, the input folio of netfs API is may not the page
cache inside the address space of the netfs file. Instead it may be just
a temporary page used to contain the data.

Thus iterate corresponding pages through rreq->folio directly.

Signed-off-by: Jeffle Xu <jefflexu at linux.alibaba.com>
---
 fs/netfs/read_helper.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/fs/netfs/read_helper.c b/fs/netfs/read_helper.c
index 04d0cc2fca83..af12a7996672 100644
--- a/fs/netfs/read_helper.c
+++ b/fs/netfs/read_helper.c
@@ -414,6 +414,22 @@ static void netfs_rreq_unlock(struct netfs_read_request *rreq)
 	pgoff_t last_page = ((rreq->start + rreq->len) / PAGE_SIZE) - 1;
 	bool subreq_failed = false;
 
+	if (rreq->type == NETFS_TYPE_DEMAND) {
+		folio = rreq->folio;
+
+		list_for_each_entry(subreq, &rreq->subrequests, rreq_link) {
+			subreq_failed = (subreq->error < 0);
+			if (subreq_failed)
+				break;
+		}
+
+		if (!subreq_failed)
+			folio_mark_uptodate(folio);
+
+		if (!test_bit(NETFS_RREQ_DONT_UNLOCK_FOLIOS, &rreq->flags))
+			folio_unlock(folio);
+	} else {
+
 	XA_STATE(xas, &rreq->mapping->i_pages, start_page);
 
 	if (test_bit(NETFS_RREQ_FAILED, &rreq->flags)) {
@@ -480,6 +496,7 @@ static void netfs_rreq_unlock(struct netfs_read_request *rreq)
 		}
 	}
 	rcu_read_unlock();
+	}
 
 	task_io_account_read(account);
 	if (rreq->netfs_ops->done)
-- 
2.27.0