xfs: handle zero entries case in xfs_iext_rebalance_leaf

And also rename fill to nr_entries to match the rest of the code.

Reported-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

diff --git a/fs/xfs/libxfs/xfs_iext_tree.c b/fs/xfs/libxfs/xfs_iext_tree.c
index 81e0480822d88a6ed71b97942f242313a80091d0..343a94246f5bb6b42d87ebf282819b0c6f588f97 100644 (file)
--- a/fs/xfs/libxfs/xfs_iext_tree.c
+++ b/fs/xfs/libxfs/xfs_iext_tree.c
@@ -787,13 +787,21 @@ xfs_iext_rebalance_leaf(
        struct xfs_iext_cursor  *cur,
        struct xfs_iext_leaf    *leaf,
        xfs_fileoff_t           offset,
-       int                     fill)
+       int                     nr_entries)
 {
+       /*
+        * If the neighbouring nodes are completely full we might never be able
+        * to merge our node, and will only delete it once the number of
+        * entries hits zero.
+        */
+       if (nr_entries == 0)
+               goto remove_node;
+
        if (leaf->prev) {
                int nr_prev = xfs_iext_leaf_nr_entries(ifp, leaf->prev, 0), i;
 
-               if (nr_prev + fill <= RECS_PER_LEAF) {
-                       for (i = 0; i < fill; i++)
+               if (nr_prev + nr_entries <= RECS_PER_LEAF) {
+                       for (i = 0; i < nr_entries; i++)
                                leaf->prev->recs[nr_prev + i] = leaf->recs[i];
 
                        if (cur->leaf == leaf) {
@@ -807,18 +815,20 @@ xfs_iext_rebalance_leaf(
        if (leaf->next) {
                int nr_next = xfs_iext_leaf_nr_entries(ifp, leaf->next, 0), i;
 
-               if (fill + nr_next <= RECS_PER_LEAF) {
+               if (nr_entries + nr_next <= RECS_PER_LEAF) {
                        /*
                         * Merge the next node into this node so that we don't
                         * have to do an additional update of the keys in the
                         * higher levels.
                         */
-                       for (i = 0; i < nr_next; i++)
-                               leaf->recs[fill + i] = leaf->next->recs[i];
+                       for (i = 0; i < nr_next; i++) {
+                               leaf->recs[nr_entries + i] =
+                                       leaf->next->recs[i];
+                       }
 
                        if (cur->leaf == leaf->next) {
                                cur->leaf = leaf;
-                               cur->pos += fill;
+                               cur->pos += nr_entries;
                        }
 
                        offset = xfs_iext_leaf_key(leaf->next, 0);