Commit 3ef0f720 authored May 14, 2008 by Miklos Szeredi Committed by Linus Torvalds May 14, 2008

mm: fix infinite loop in filemap_fault



filemap_fault will go into an infinite loop if ->readpage() fails
asynchronously.

AFAICS the bug was introduced by this commit, which removed the wait after the
final readpage:

   commit d00806b1
   Author: Nick Piggin <npiggin@suse.de>
   Date:   Thu Jul 19 01:46:57 2007 -0700

       mm: fix fault vs invalidate race for linear mappings

Fix by reintroducing the wait_on_page_locked() after ->readpage() to make sure
the page is up-to-date before jumping back to the beginning of the function.

I've noticed this while testing nfs exporting on fuse.  The patch
fixes it.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Cc: Nick Piggin <npiggin@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 3b73a223

mm/filemap.c

+5 −0

Original line number	Diff line number	Diff line
		@@ -1461,6 +1461,11 @@ page_not_uptodate:
		*/
		ClearPageError(page);
		error = mapping->a_ops->readpage(file, page);
		if (!error) {
		wait_on_page_locked(page);
		if (!PageUptodate(page))
		error = -EIO;
		}
		page_cache_release(page);

		if (!error \|\| error == AOP_TRUNCATED_PAGE)

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