xfs: growfs: don't read garbage for new secondary superblocks
[~shefty/rdma-dev.git] / fs / xfs / xfs_fsops.c
index c25b094efbf715186f39a9b7a44466eb0a910374..4beaede43277b15c8d5a28ffbaadb4b573d7a709 100644 (file)
@@ -399,9 +399,26 @@ xfs_growfs_data_private(
 
        /* update secondary superblocks. */
        for (agno = 1; agno < nagcount; agno++) {
-               error = xfs_trans_read_buf(mp, NULL, mp->m_ddev_targp,
+               error = 0;
+               /*
+                * new secondary superblocks need to be zeroed, not read from
+                * disk as the contents of the new area we are growing into is
+                * completely unknown.
+                */
+               if (agno < oagcount) {
+                       error = xfs_trans_read_buf(mp, NULL, mp->m_ddev_targp,
                                  XFS_AGB_TO_DADDR(mp, agno, XFS_SB_BLOCK(mp)),
                                  XFS_FSS_TO_BB(mp, 1), 0, &bp);
+               } else {
+                       bp = xfs_trans_get_buf(NULL, mp->m_ddev_targp,
+                                 XFS_AGB_TO_DADDR(mp, agno, XFS_SB_BLOCK(mp)),
+                                 XFS_FSS_TO_BB(mp, 1), 0);
+                       if (bp)
+                               xfs_buf_zero(bp, 0, BBTOB(bp->b_length));
+                       else
+                               error = ENOMEM;
+               }
+
                if (error) {
                        xfs_warn(mp,
                "error %d reading secondary superblock for ag %d",
@@ -423,7 +440,7 @@ xfs_growfs_data_private(
                        break; /* no point in continuing */
                }
        }
-       return 0;
+       return error;
 
  error0:
        xfs_trans_cancel(tp, XFS_TRANS_ABORT);