1 files changed, 20 insertions, 33 deletions

diff --git a/mm/filemap.c b/mm/filemap.c
index 5d5449f3d41c..462cda58a18e 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1325,9 +1325,10 @@ struct page *filemap_nopage(struct vm_area_struct *area,
         unsigned long size, pgoff;
         int did_readaround = 0, majmin = VM_FAULT_MINOR;
 
+        BUG_ON(!(area->vm_flags & VM_CAN_INVALIDATE));
+
         pgoff = ((address-area->vm_start) >> PAGE_CACHE_SHIFT) + area->vm_pgoff;
 
-retry_all:
         size = (i_size_read(inode) + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
         if (pgoff >= size)
                 goto outside_data_content;
@@ -1349,7 +1350,7 @@ retry_all:
          * Do we have something in the page cache already?
          */
 retry_find:
-        page = find_get_page(mapping, pgoff);
+        page = find_lock_page(mapping, pgoff);
         if (!page) {
                 unsigned long ra_pages;
 
@@ -1383,7 +1384,7 @@ retry_find:
                                 start = pgoff - ra_pages / 2;
                         do_page_cache_readahead(mapping, file, start, ra_pages);
                 }
-                page = find_get_page(mapping, pgoff);
+                page = find_lock_page(mapping, pgoff);
                 if (!page)
                         goto no_cached_page;
         }
@@ -1392,13 +1393,19 @@ retry_find:
                 ra->mmap_hit++;
 
         /*
-         * Ok, found a page in the page cache, now we need to check
-         * that it's up-to-date.
+         * We have a locked page in the page cache, now we need to check
+         * that it's up-to-date. If not, it is going to be due to an error.
          */
-        if (!PageUptodate(page))
+        if (unlikely(!PageUptodate(page)))
                 goto page_not_uptodate;
 
-success:
+        /* Must recheck i_size under page lock */
+        size = (i_size_read(inode) + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
+        if (unlikely(pgoff >= size)) {
+                unlock_page(page);
+                goto outside_data_content;
+        }
+
         /*
          * Found the page and have a reference on it.
          */
@@ -1440,6 +1447,7 @@ no_cached_page:
         return NOPAGE_SIGBUS;
 
 page_not_uptodate:
+        /* IO error path */
         if (!did_readaround) {
                 majmin = VM_FAULT_MAJOR;
                 count_vm_event(PGMAJFAULT);
@@ -1451,37 +1459,15 @@ page_not_uptodate:
          * because there really aren't any performance issues here
          * and we need to check for errors.
          */
-        lock_page(page);
-
-        /* Somebody truncated the page on us? */
-        if (!page->mapping) {
-                unlock_page(page);
-                page_cache_release(page);
-                goto retry_all;
-        }
-
-        /* Somebody else successfully read it in? */
-        if (PageUptodate(page)) {
-                unlock_page(page);
-                goto success;
-        }
         ClearPageError(page);
         error = mapping->a_ops->readpage(file, page);
-        if (!error) {
-                wait_on_page_locked(page);
-                if (PageUptodate(page))
-                        goto success;
-        } else if (error == AOP_TRUNCATED_PAGE) {
-                page_cache_release(page);
+        page_cache_release(page);
+
+        if (!error || error == AOP_TRUNCATED_PAGE)
                 goto retry_find;
-        }
 
-        /*
-         * Things didn't work out. Return zero to tell the
-         * mm layer so, possibly freeing the page cache page first.
-         */
+        /* Things didn't work out. Return zero to tell the mm layer so. */
         shrink_readahead_size_eio(file, ra);
-        page_cache_release(page);
         return NOPAGE_SIGBUS;
 }
 EXPORT_SYMBOL(filemap_nopage);
@@ -1674,6 +1660,7 @@ int generic_file_mmap(struct file * file, struct vm_area_struct * vma)
                 return -ENOEXEC;
         file_accessed(file);
         vma->vm_ops = &generic_file_vm_ops;
+        vma->vm_flags |= VM_CAN_INVALIDATE;
         return 0;
 }