xfs: Fix open flag handling in open_by_handle code

Sparse identified some unsafe handling of open flags in the xfs open
by handle ioctl code. Update the code to use the correct access
macros to ensure that we handle the open flags correctly.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>

1 files changed, 5 insertions, 9 deletions

diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
index f588320dc4b9..91f8ff547ab3 100644
--- a/fs/xfs/xfs_ioctl.c
+++ b/fs/xfs/xfs_ioctl.c
@@ -209,6 +209,7 @@ xfs_open_by_handle(
         struct file             *filp;
         struct inode            *inode;
         struct dentry           *dentry;
+        fmode_t                 fmode;
 
         if (!capable(CAP_SYS_ADMIN))
                 return -XFS_ERROR(EPERM);
@@ -228,26 +229,21 @@ xfs_open_by_handle(
         hreq->oflags |= O_LARGEFILE;
 #endif
 
-        /* Put open permission in namei format. */
         permflag = hreq->oflags;
-        if ((permflag+1) & O_ACCMODE)
-                permflag++;
-        if (permflag & O_TRUNC)
-                permflag |= 2;
-
+        fmode = OPEN_FMODE(permflag);
         if ((!(permflag & O_APPEND) || (permflag & O_TRUNC)) &&
-            (permflag & FMODE_WRITE) && IS_APPEND(inode)) {
+            (fmode & FMODE_WRITE) && IS_APPEND(inode)) {
                 error = -XFS_ERROR(EPERM);
                 goto out_dput;
         }
 
-        if ((permflag & FMODE_WRITE) && IS_IMMUTABLE(inode)) {
+        if ((fmode & FMODE_WRITE) && IS_IMMUTABLE(inode)) {
                 error = -XFS_ERROR(EACCES);
                 goto out_dput;
         }
 
         /* Can't write directories. */
-        if (S_ISDIR(inode->i_mode) && (permflag & FMODE_WRITE)) {
+        if (S_ISDIR(inode->i_mode) && (fmode & FMODE_WRITE)) {
                 error = -XFS_ERROR(EISDIR);
                 goto out_dput;
         }