NFS: Fix a potential deadlock in nfs_release_page

nfs_wb_page() waits on request completion and, as a result, is not safe to be
called from nfs_release_page() invoked by VM scanner as part of GFP_NOFS
allocation. Fix possible deadlock by analyzing gfp mask and refusing to
release page if __GFP_FS is not set.

Signed-off-by: Nikita Danilov <danilov@gmail.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
(cherry picked from 374d969debfb290bafcb41d28918dc6f7e43ce31 commit)
This commit is contained in:
Nikita Danilov 2006-08-09 13:53:47 -04:00 коммит произвёл Trond Myklebust
Родитель ef7d1b244f
Коммит ddeff520f0
1 изменённых файлов: 7 добавлений и 1 удалений

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@ -312,7 +312,13 @@ static void nfs_invalidate_page(struct page *page, unsigned long offset)
static int nfs_release_page(struct page *page, gfp_t gfp)
{
return !nfs_wb_page(page->mapping->host, page);
if (gfp & __GFP_FS)
return !nfs_wb_page(page->mapping->host, page);
else
/*
* Avoid deadlock on nfs_wait_on_request().
*/
return 0;
}
const struct address_space_operations nfs_file_aops = {