teach page_get_link() to work in RCU mode
more or less along the lines of Neil's patchset, sans the insanity
around kmap().
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/namei.c b/fs/namei.c
index 1da3064..8f51788 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -4533,12 +4533,19 @@
struct page *page;
struct address_space *mapping = inode->i_mapping;
- if (!dentry)
- return ERR_PTR(-ECHILD);
-
- page = read_mapping_page(mapping, 0, NULL);
- if (IS_ERR(page))
- return (char*)page;
+ if (!dentry) {
+ page = find_get_page(mapping, 0);
+ if (!page)
+ return ERR_PTR(-ECHILD);
+ if (!PageUptodate(page)) {
+ put_page(page);
+ return ERR_PTR(-ECHILD);
+ }
+ } else {
+ page = read_mapping_page(mapping, 0, NULL);
+ if (IS_ERR(page))
+ return (char*)page;
+ }
*cookie = page;
BUG_ON(mapping_gfp_mask(mapping) & __GFP_HIGHMEM);
kaddr = page_address(page);