[Cluster-devel] [GFS2] Patch to correct lock ordering of unlink

[Steven Whitehouse]

Hi,

The following corrects the unlink lock ordering to parent -> child -> rgrp in
common with the rest of GFS2,

Steve.

diff --git a/fs/gfs2/ops_inode.c b/fs/gfs2/ops_inode.c
index 5b8b994..2cbe5a3 100644
--- a/fs/gfs2/ops_inode.c
+++ b/fs/gfs2/ops_inode.c
@@ -278,17 +278,25 @@ static int gfs2_unlink(struct inode *dir, struct dentry 
*dentry)
        gfs2_holder_init(rgd->rd_gl, LM_ST_EXCLUSIVE, 0, ghs + 2);
 
 
-       error = gfs2_glock_nq_m(3, ghs);
+       error = gfs2_glock_nq(ghs); /* parent */
        if (error)
-               goto out;
+               goto out_parent;
+
+       error = gfs2_glock_nq(ghs + 1); /* child */
+       if (error)
+               goto out_child;
+
+       error = gfs2_glock_nq(ghs + 2); /* rgrp */
+       if (error)
+               goto out_rgrp;
 
        error = gfs2_unlink_ok(dip, &dentry->d_name, ip);
        if (error)
-               goto out_gunlock;
+               goto out_rgrp;
 
        error = gfs2_trans_begin(sdp, 2*RES_DINODE + RES_LEAF + RES_RG_BIT, 0);
        if (error)
-               goto out_gunlock;
+               goto out_rgrp;
 
        error = gfs2_dir_del(dip, &dentry->d_name);
         if (error)
@@ -298,12 +306,15 @@ static int gfs2_unlink(struct inode *dir, struct dentry 
*dentry)
 
 out_end_trans:
        gfs2_trans_end(sdp);
-out_gunlock:
-       gfs2_glock_dq_m(3, ghs);
-out:
-       gfs2_holder_uninit(ghs);
-       gfs2_holder_uninit(ghs + 1);
+       gfs2_glock_dq(ghs + 2);
+out_rgrp:
        gfs2_holder_uninit(ghs + 2);
+       gfs2_glock_dq(ghs + 1);
+out_child:
+       gfs2_holder_uninit(ghs + 1);
+       gfs2_glock_dq(ghs);
+out_parent:
+       gfs2_holder_uninit(ghs);
        gfs2_glock_dq_uninit(&ri_gh);
        return error;
 }