[Linux-cachefs] [PATCH v3 2/6] ceph: rework PageFsCache handling

[Jeff Layton]

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.

Also define FSCACHE_USE_NEW_IO_API so that we opt into the new fscache
API.

Signed-off-by: Jeff Layton <jlayton at kernel.org>
Cc: ceph-devel at vger.kernel.org
Cc: linux-cachefs at redhat.com
Cc: linux-fsdevel at vger.kernel.org
---
 fs/ceph/addr.c  | 9 ++++++++-
 fs/ceph/super.h | 1 +
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
index e267aa60c8b6..3936ae3e8dcd 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)
 {
 	dout("%p releasepage %p idx %lu (%sdirty)\n", page->mapping->host,
 	     page, page->index, PageDirty(page) ? "" : "not ");
 
+	if (PageFsCache(page)) {
+		if (!(gfp & __GFP_DIRECT_RECLAIM) || !(gfp & __GFP_FS))
+			return 0;
+		wait_on_page_fscache(page);
+	}
 	return !PagePrivate(page);
 }
 
diff --git a/fs/ceph/super.h b/fs/ceph/super.h
index 060c93df9b93..2f7e769290c4 100644
--- a/fs/ceph/super.h
+++ b/fs/ceph/super.h
@@ -21,6 +21,7 @@
 #include <linux/ceph/libceph.h>
 
 #ifdef CONFIG_CEPH_FSCACHE
+#define FSCACHE_USE_NEW_IO_API
 #include <linux/fscache.h>
 #endif
 
-- 
2.29.2