nfsd4: fix break_lease flags on nfsd open

Thanks to Casey Bodley for pointing out that on a read open we pass 0,
instead of O_RDONLY, to break_lease, with the result that a read open is
treated like a write open for the purposes of lease breaking!

Reported-by: Casey Bodley <cbodley@citi.umich.edu>
Cc: stable@kernel.org
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

1 files changed, 9 insertions, 6 deletions

diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index f3fb61b69a1e..fd0acca5370a 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -696,7 +696,15 @@ nfsd_access(struct svc_rqst *rqstp, struct svc_fh *fhp, u32 *access, u32 *suppor
 }
 #endif /* CONFIG_NFSD_V3 */
 
+static int nfsd_open_break_lease(struct inode *inode, int access)
+{
+        unsigned int mode;
 
+        if (access & NFSD_MAY_NOT_BREAK_LEASE)
+                return 0;
+        mode = (access & NFSD_MAY_WRITE) ? O_WRONLY : O_RDONLY;
+        return break_lease(inode, mode | O_NONBLOCK);
+}
 
 /*
  * Open an existing file or directory.
@@ -744,12 +752,7 @@ nfsd_open(struct svc_rqst *rqstp, struct svc_fh *fhp, int type,
         if (!inode->i_fop)
                 goto out;
 
-        /*
-         * Check to see if there are any leases on this file.
-         * This may block while leases are broken.
-         */
-        if (!(access & NFSD_MAY_NOT_BREAK_LEASE))
-                host_err = break_lease(inode, O_NONBLOCK | ((access & NFSD_MAY_WRITE) ? O_WRONLY : 0));
+        host_err = nfsd_open_break_lease(inode, access);
         if (host_err) /* NOMEM or WOULDBLOCK */
                 goto out_nfserr;