Commit ddeff520 authored Aug 09, 2006 by Nikita Danilov Committed by Trond Myklebust Aug 24, 2006

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)

parent ef7d1b24

fs/nfs/file.c

+7 −1

Original line number	Diff line number	Diff line
		@@ -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)
		{
		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 = {

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