aio: first support for buffered async writes

[linux-block.git] / mm / filemap.c

diff --git a/mm/filemap.c b/mm/filemap.c
index 4fffb32ba3a71e1e587bc2be0b888bd29a04921a..26348d3bdcb4b3721df66c3c38d6e057655ccaf4 100644 (file)
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -693,24 +693,22 @@ repeat:
 }
 EXPORT_SYMBOL(find_get_page);
 
-/**
- * find_lock_page - locate, pin and lock a pagecache page
- * @mapping: the address_space to search
- * @offset: the page index
- *
- * Locates the desired pagecache page, locks it, increments its reference
- * count and returns its address.
- *
- * Returns zero if the page was not present. find_lock_page() may sleep.
- */
-struct page *find_lock_page(struct address_space *mapping, pgoff_t offset)
+struct page *find_lock_page_async(struct address_space *mapping, pgoff_t offset,
+                                 struct wait_bit_queue *wait)
 {
        struct page *page;
 
 repeat:
        page = find_get_page(mapping, offset);
        if (page) {
-               lock_page(page);
+               int ret;
+
+               ret = lock_page_async(page, wait);
+               if (ret) {
+                       page_cache_release(page);
+                       page = ERR_PTR(ret);
+                       goto out;
+               }
                /* Has the page been truncated? */
                if (unlikely(page->mapping != mapping)) {
                        unlock_page(page);
@@ -719,8 +717,26 @@ repeat:
                }
                VM_BUG_ON(page->index != offset);
        }
+out:
        return page;
 }
+EXPORT_SYMBOL(find_lock_page_async);
+
+/**
+ * find_lock_page - locate, pin and lock a pagecache page
+ * @mapping: the address_space to search
+ * @offset: the page index
+ *
+ * Locates the desired pagecache page, locks it, increments its reference
+ * count and returns its address.
+ *
+ * Returns zero if the page was not present. find_lock_page() may sleep.
+ */
+struct page *find_lock_page(struct address_space *mapping, pgoff_t offset)
+{
+
+       return find_lock_page_async(mapping, offset, NULL);
+}
 EXPORT_SYMBOL(find_lock_page);
 
 /**
@@ -2183,8 +2199,8 @@ struct page *grab_cache_page_write_begin(struct address_space *mapping,
        if (flags & AOP_FLAG_NOFS)
                gfp_notmask = __GFP_FS;
 repeat:
-       page = find_lock_page(mapping, index);
-       if (likely(page))
+       page = find_lock_page_async(mapping, index, current->io_wait);
+       if (page || IS_ERR(page))
                return page;
 
        page = __page_cache_alloc(mapping_gfp_mask(mapping) & ~gfp_notmask);