[PATCH 59/67] NFS: Convert fscache_enable_cookie and fscache_disable_cookie

[David Howells]

From: Dave Wysochanski <dwysocha at redhat.com>

The new FS-Cache API removes the fscache_enable_cookie() and
fscache_disable_cookie() in favor of the new APIs
fscache_use_cookie() and fscache_unuse_cookie(), so update these
areas as needed.

For NFS, we enable fscache on an inode only if the inode is open
readonly and not if the inode is open for write.  Use the new
APIs and change the existing logic slightly and make a decision
whether to "use" an inode based fscache cookie one time, by gating
the call to fscache_use_cookie() and fscache_unuse_cookie()
by the NFS_INO_FSCACHE flag on the nfs_inode.

Signed-off-by: Dave Wysochanski <dwysocha at redhat.com>
Signed-off-by: David Howells <dhowells at redhat.com>
cc: Trond Myklebust <trond.myklebust at hammerspace.com>
cc: Anna Schumaker <anna.schumaker at netapp.com>
cc: linux-nfs at vger.kernel.org
---

 fs/nfs/fscache.c |   24 +++++++++++++-----------
 1 file changed, 13 insertions(+), 11 deletions(-)

diff --git a/fs/nfs/fscache.c b/fs/nfs/fscache.c
index 514d50d079a2..5e584f2e84a9 100644
--- a/fs/nfs/fscache.c
+++ b/fs/nfs/fscache.c
@@ -285,7 +285,10 @@ void nfs_fscache_clear_inode(struct inode *inode)
 
 	dfprintk(FSCACHE, "NFS: clear cookie (0x%p/0x%p)\n", nfsi, cookie);
 
-	nfs_fscache_update_auxdata(&auxdata, nfsi);
+	if (test_and_clear_bit(NFS_INO_FSCACHE, &NFS_I(inode)->flags)) {
+		nfs_fscache_update_auxdata(&auxdata, nfsi);
+		fscache_unuse_cookie(cookie, &auxdata, NULL);
+	}
 	fscache_relinquish_cookie(cookie, false);
 	nfsi->fscache = NULL;
 }
@@ -325,18 +328,17 @@ void nfs_fscache_open_file(struct inode *inode, struct file *filp)
 	if (!fscache_cookie_valid(cookie))
 		return;
 
-	nfs_fscache_update_auxdata(&auxdata, nfsi);
-
 	if (inode_is_open_for_write(inode)) {
-		dfprintk(FSCACHE, "NFS: nfsi 0x%p disabling cache\n", nfsi);
-		clear_bit(NFS_INO_FSCACHE, &nfsi->flags);
-		fscache_disable_cookie(cookie, &auxdata, true);
+		if (test_and_clear_bit(NFS_INO_FSCACHE, &nfsi->flags)) {
+			dfprintk(FSCACHE, "NFS: nfsi 0x%p disabling cache\n", nfsi);
+			nfs_fscache_update_auxdata(&auxdata, nfsi);
+			fscache_unuse_cookie(cookie, &auxdata, NULL);
+		}
 	} else {
-		dfprintk(FSCACHE, "NFS: nfsi 0x%p enabling cache\n", nfsi);
-		fscache_enable_cookie(cookie, &auxdata, nfsi->vfs_inode.i_size,
-				      nfs_fscache_can_enable, inode);
-		if (fscache_cookie_enabled(cookie))
-			set_bit(NFS_INO_FSCACHE, &NFS_I(inode)->flags);
+		if (!test_and_set_bit(NFS_INO_FSCACHE, &nfsi->flags)) {
+			dfprintk(FSCACHE, "NFS: nfsi 0x%p enabling cache\n", nfsi);
+			fscache_use_cookie(cookie, false);
+		}
 	}
 }
 EXPORT_SYMBOL_GPL(nfs_fscache_open_file);