[PATCH 5/6] nfs: Add comment on PG_private use of NFS

Peter Zijlstra
2006-08-25T15:43:06Z

Add a comment explaining the use of PG_private in the NFS client.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
---
fs/nfs/write.c | 5 +++++
1 file changed, 5 insertions(+)

Index: linux-2.6/fs/nfs/write.c
===================================================================
--- linux-2.6.orig/fs/nfs/write.c
+++ linux-2.6/fs/nfs/write.c
@@ -424,6 +424,11 @@ static int nfs_inode_add_request(struct
if (nfs_have_delegation(inode, FMODE_WRITE))
nfsi->change_attr++;
}
+ /*
+ * The PG_private bit is unfortunately needed if we want to fix the
+ * hole in the mmap semantics. If we do not set it, then the VM will
+ * fail to call the "releasepage" address ops.
+ */
SetPagePrivate(req->wb_page);
nfsi->npages++;
atomic_inc(&req->wb_count);