nfsd4: fix downgrade/lock logic

If we already had a RW open for a file, and get a readonly open, we were
piggybacking on the existing RW open.  That's inconsistent with the
downgrade logic which blows away the RW open assuming you'll still have
a readonly open.

Also, make sure there is a readonly or writeonly open available for
locking, again to prevent bad behavior in downgrade cases when any RW
open may be lost.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>

1 files changed, 6 insertions, 6 deletions

diff --git a/fs/nfsd/state.h b/fs/nfsd/state.h
index 84579c86b13d..322518c88e4b 100644
--- a/fs/nfsd/state.h
+++ b/fs/nfsd/state.h
@@ -363,16 +363,16 @@ struct nfs4_file {
  * at all? */
 static inline struct file *find_writeable_file(struct nfs4_file *f)
 {
-        if (f->fi_fds[O_RDWR])
-                return f->fi_fds[O_RDWR];
-        return f->fi_fds[O_WRONLY];
+        if (f->fi_fds[O_WRONLY])
+                return f->fi_fds[O_WRONLY];
+        return f->fi_fds[O_RDWR];
 }
 
 static inline struct file *find_readable_file(struct nfs4_file *f)
 {
-        if (f->fi_fds[O_RDWR])
-                return f->fi_fds[O_RDWR];
-        return f->fi_fds[O_RDONLY];
+        if (f->fi_fds[O_RDONLY])
+                return f->fi_fds[O_RDONLY];
+        return f->fi_fds[O_RDWR];
 }
 
 static inline struct file *find_any_file(struct nfs4_file *f)