1 files changed, 12 insertions, 8 deletions

diff --git a/mm/filemap.c b/mm/filemap.c
index 6b9aee20f242..83a45d35468b 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -102,9 +102,6 @@
  *    ->inode_lock              (zap_pte_range->set_page_dirty)
  *    ->private_lock            (zap_pte_range->__set_page_dirty_buffers)
  *
- *  ->task->proc_lock
- *    ->dcache_lock             (proc_pid_lookup)
- *
  *  (code doesn't rely on that order, so you could switch it around)
  *  ->tasklist_lock             (memory_failure, collect_procs_ao)
  *    ->i_mmap_lock
@@ -301,7 +298,7 @@ int filemap_fdatawait_range(struct address_space *mapping, loff_t start_byte,
                                 continue;
 
                         wait_on_page_writeback(page);
-                        if (PageError(page))
+                        if (TestClearPageError(page))
                                 ret = -EIO;
                 }
                 pagevec_release(&pvec);
@@ -840,9 +837,6 @@ repeat:
                 if (radix_tree_deref_retry(page))
                         goto restart;
 
-                if (page->mapping == NULL || page->index != index)
-                        break;
-
                 if (!page_cache_get_speculative(page))
                         goto repeat;
 
@@ -852,6 +846,16 @@ repeat:
                         goto repeat;
                 }
 
+                /*
+                 * must check mapping and index after taking the ref.
+                 * otherwise we can get both false positives and false
+                 * negatives, which is just confusing to the caller.
+                 */
+                if (page->mapping == NULL || page->index != index) {
+                        page_cache_release(page);
+                        break;
+                }
+
                 pages[ret] = page;
                 ret++;
                 index++;
@@ -2223,7 +2227,7 @@ struct page *grab_cache_page_write_begin(struct address_space *mapping,
                 gfp_notmask = __GFP_FS;
 repeat:
         page = find_lock_page(mapping, index);
-        if (likely(page))
+        if (page)
                 return page;
 
         page = __page_cache_alloc(mapping_gfp_mask(mapping) & ~gfp_notmask);