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

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Date:   Tue, 26 Jan 2021 08:40:59 -0500
From:   Jeff Layton <jlayton@...nel.org>
To:     ceph-devel@...r.kernel.org, idryomov@...il.com, dhowells@...hat.com
Cc:     willy@...radead.org, linux-fsdevel@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-cachefs@...hat.com
Subject: [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 | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
index 2b17bb36e548..fbfa49db06fd 100644
--- a/fs/ceph/addr.c
+++ b/fs/ceph/addr.c
@@ -146,6 +146,8 @@ static void ceph_invalidatepage(struct page *page, unsigned int offset,
 	struct ceph_inode_info *ci;
 	struct ceph_snap_context *snapc = page_snap_context(page);
 
+	wait_on_page_fscache(page);
+
 	inode = page->mapping->host;
 	ci = ceph_inode(inode);
 
@@ -168,11 +170,16 @@ static void ceph_invalidatepage(struct page *page, unsigned int offset,
 	ClearPagePrivate(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