[PATCH] xfs_repair: don't crash if we run out of space midway through rebuilding a btree

["Darrick J. Wong" <darrick.wong@xxxxxxxxxx>]

During btree rebuilding, the cursor setup function checks ext_ptr to
report ENOSPC problems when it grabs the first extent for the btree.
However, subsequent grabs for free space don't check ext_ptr and so we
segfault if there's no space.  Therefore, move the ENOSPC check into
the loop so that we always complain about insufficient space instead
of just crashing.

Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
---
 repair/phase5.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/repair/phase5.c b/repair/phase5.c
index b464b56..28aaefe 100644
--- a/repair/phase5.c
+++ b/repair/phase5.c
@@ -231,8 +231,7 @@ setup_cursor(xfs_mount_t *mp, xfs_agnumber_t agno, 
bt_status_t *curs)
         * grab the smallest extent and use it up, then get the
         * next smallest.  This mimics the init_*_cursor code.
         */
-       if ((ext_ptr =  findfirst_bcnt_extent(agno)) == NULL)
-               do_error(_("error - not enough free space in filesystem\n"));
+       ext_ptr =  findfirst_bcnt_extent(agno);
 
        agb_ptr = curs->btree_blocks;
 
@@ -240,6 +239,9 @@ setup_cursor(xfs_mount_t *mp, xfs_agnumber_t agno, 
bt_status_t *curs)
         * set up the free block array
         */
        while (blocks_allocated < big_extent_len)  {
+               if (!ext_ptr)
+                       do_error(
+_("error - not enough free space in filesystem\n"));
                /*
                 * use up the extent we've got
                 */