linux-kernel - [RFC PATCH 2/6] ceph: rework PageFsCache handling

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Date:   Fri, 22 Jan 2021 12:51:14 -0500
From:   Jeff Layton <jlayton@...nel.org>
To:     ceph-devel@...r.kernel.org
Cc:     linux-fsdevel@...r.kernel.org, dhowells@...hat.com,
        willy@...radead.org, linux-cachefs@...hat.com,
        linux-kernel@...r.kernel.org
Subject: [RFC PATCH 2/6] ceph: rework PageFsCache handling

With the new fscache API, the PageFsCache bit now indicates that the
page is being written to the cache and shouldn't be modified or released
until it's finished.

Change releasepage and invalidatepage to wait on that bit before
returning.

Signed-off-by: Jeff Layton <jlayton@...nel.org>
---
 fs/ceph/addr.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
index e267aa60c8b6..f554667e1e91 100644
--- a/fs/ceph/addr.c
+++ b/fs/ceph/addr.c
@@ -166,13 +166,19 @@ static void ceph_invalidatepage(struct page *page, unsigned int offset,
 	ceph_put_snap_context(snapc);
 	page->private = 0;
 	ClearPagePrivate(page);
+	wait_on_page_fscache(page);
 }
 
-static int ceph_releasepage(struct page *page, gfp_t g)
+static int ceph_releasepage(struct page *page, gfp_t gfp_flags)
 {
 	dout("%p releasepage %p idx %lu (%sdirty)\n", page->mapping->host,
 	     page, page->index, PageDirty(page) ? "" : "not ");
 
+	if (PageFsCache(page)) {
+		if (!(gfp_flags & __GFP_DIRECT_RECLAIM) || !(gfp_flags & __GFP_FS))
+			return 0;
+		wait_on_page_fscache(page);
+	}
 	return !PagePrivate(page);
 }
 
-- 
2.29.2