NFSv4: Fix problem with OPEN_DOWNGRADE
RFC 3530 states that for OPEN_DOWNGRADE "The share_access and share_deny
bits specified must be exactly equal to the union of the share_access and
share_deny bits specified for some subset of the OPENs in effect for
current openowner on the current file.
Setattr is currently violating the NFSv4 rules for OPEN_DOWNGRADE in that
it may cause a downgrade from OPEN4_SHARE_ACCESS_BOTH to
OPEN4_SHARE_ACCESS_WRITE despite the fact that there exists no open file
with O_WRONLY access mode.
Fix the problem by replacing nfs4_find_state() with a modified version of
nfs_find_open_context().
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index 819a65f..1bdbd4f 100644
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -294,7 +294,7 @@
if (page->index >= end_index+1 || !offset)
goto out;
do_it:
- ctx = nfs_find_open_context(inode, FMODE_WRITE);
+ ctx = nfs_find_open_context(inode, NULL, FMODE_WRITE);
if (ctx == NULL) {
err = -EBADF;
goto out;