ocfs2: take inode lock in ocfs2_iop_set/get_acl()

This bug in mainline code is pointed out by Mark Fasheh.  When
ocfs2_iop_set_acl() and ocfs2_iop_get_acl() are entered from VFS layer,
inode lock is not held.  This seems to be regression from older kernels.
The patch is to fix that.

Orabug: 20189959
Signed-off-by: Tariq Saeed <tariq.x.saeed@oracle.com>
Reviewed-by: Mark Fasheh <mfasheh@suse.de>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Author: Tariq Saeed

fs/ocfs2/acl.c

@@ -284,27 +284,41 @@ int ocfs2_set_acl(handle_t *handle,
 
 int ocfs2_iop_set_acl(struct inode *inode, struct posix_acl *acl, int type)
 {
-	return ocfs2_set_acl(NULL, inode, NULL, type, acl, NULL, NULL);
+	struct buffer_head *bh = NULL;
+	int status = 0;
+
+	status = ocfs2_inode_lock(inode, &bh, 1);
+	if (status < 0) {
+		if (status != -ENOENT)
+			mlog_errno(status);
+		return status;
+	}
+	status = ocfs2_set_acl(NULL, inode, bh, type, acl, NULL, NULL);
+	ocfs2_inode_unlock(inode, 1);
+	brelse(bh);
+	return status;
 }
 
 struct posix_acl *ocfs2_iop_get_acl(struct inode *inode, int type)
 {
 	struct ocfs2_super *osb;
 	struct buffer_head *di_bh = NULL;
 	struct posix_acl *acl;
-	int ret = -EAGAIN;
+	int ret;
 
 	osb = OCFS2_SB(inode->i_sb);
 	if (!(osb->s_mount_opt & OCFS2_MOUNT_POSIX_ACL))
 		return NULL;
-
-	ret = ocfs2_read_inode_block(inode, &di_bh);
-	if (ret < 0)
+	ret = ocfs2_inode_lock(inode, &di_bh, 0);
+	if (ret < 0) {
+		if (ret != -ENOENT)
+			mlog_errno(ret);
 		return ERR_PTR(ret);
+	}
 
 	acl = ocfs2_get_acl_nolock(inode, type, di_bh);
 
+	ocfs2_inode_unlock(inode, 0);
 	brelse(di_bh);
-
 	return acl;
 }