[GFS2] don't call permission()

GFS2 calls permission() to verify permissions after locks on the files
have been taken.

For this it's sufficient to call gfs2_permission() instead.  This
results in the following changes:

  - IS_RDONLY() check is not performed
  - IS_IMMUTABLE() check is not performed
  - devcgroup_inode_permission() is not called
  - security_inode_permission() is not called

IS_RDONLY() should be unnecessary anyway, as the per-mount read-only
flag should provide protection against read-only remounts during
operations.  do_gfs2_set_flags() has been fixed to perform
mnt_want_write()/mnt_drop_write() to protect against remounting
read-only.

IS_IMMUTABLE has been added to gfs2_permission()

Repeating the security checks seems to be pointless, as they don't
normally change, and if they do, it's independent of the filesystem
state.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

1 files changed, 3 insertions, 3 deletions

diff --git a/fs/gfs2/inode.c b/fs/gfs2/inode.c
index 09453d057e41..caf409083354 100644
--- a/fs/gfs2/inode.c
+++ b/fs/gfs2/inode.c
@@ -504,7 +504,7 @@ struct inode *gfs2_lookupi(struct inode *dir, const struct qstr *name,
         }
 
         if (!is_root) {
-                error = permission(dir, MAY_EXEC, NULL);
+                error = gfs2_permission(dir, MAY_EXEC);
                 if (error)
                         goto out;
         }
@@ -667,7 +667,7 @@ static int create_ok(struct gfs2_inode *dip, const struct qstr *name,
 {
         int error;
 
-        error = permission(&dip->i_inode, MAY_WRITE | MAY_EXEC, NULL);
+        error = gfs2_permission(&dip->i_inode, MAY_WRITE | MAY_EXEC);
         if (error)
                 return error;
 
@@ -1134,7 +1134,7 @@ int gfs2_unlink_ok(struct gfs2_inode *dip, const struct qstr *name,
         if (IS_APPEND(&dip->i_inode))
                 return -EPERM;
 
-        error = permission(&dip->i_inode, MAY_WRITE | MAY_EXEC, NULL);
+        error = gfs2_permission(&dip->i_inode, MAY_WRITE | MAY_EXEC);
         if (error)
                 return error;