mm/fs: fix pessimization in hole-punching pagecache

[karo-tx-linux.git] / mm / truncate.c

diff --git a/mm/truncate.c b/mm/truncate.c
index 6a78c814bebfb151b1e490424c731edc172ad430..eda2473071648cc47935dd9e21e9f57fd402a4dd 100644 (file)
--- a/mm/truncate.c
+++ b/mm/truncate.c
@@ -355,14 +355,16 @@ void truncate_inode_pages_range(struct address_space *mapping,
        for ( ; ; ) {
                cond_resched();
                if (!pagevec_lookup_entries(&pvec, mapping, index,
-                       min(end - index, (pgoff_t)PAGEVEC_SIZE),
-                       indices)) {
+                       min(end - index, (pgoff_t)PAGEVEC_SIZE), indices)) {
+                       /* If all gone from start onwards, we're done */
                        if (index == start)
                                break;
+                       /* Otherwise restart to make sure all gone */
                        index = start;
                        continue;
                }
                if (index == start && indices[0] >= end) {
+                       /* All gone out of hole to be punched, we're done */
                        pagevec_remove_exceptionals(&pvec);
                        pagevec_release(&pvec);
                        break;
@@ -373,8 +375,11 @@ void truncate_inode_pages_range(struct address_space *mapping,
 
                        /* We rely upon deletion not changing page->index */
                        index = indices[i];
-                       if (index >= end)
+                       if (index >= end) {
+                               /* Restart punch to make sure all gone */
+                               index = start - 1;
                                break;
+                       }
 
                        if (radix_tree_exceptional_entry(page)) {
                                clear_exceptional_entry(mapping, index, page);