> Page fault on NFS apparently goes into an infinite loop if the read on
> the server fails.
>
> I don't understand the NFS readpage code, but the filemap_fault() code
> looks somewhat suspicious:
>
> /*
> * Umm, take care of errors if the page isn't up-to-date.
> * Try to re-read it _once_. We do this synchronously,
> * because there really aren't any performance issues here
> * and we need to check for errors.
> */
> ClearPageError(page);
> error = mapping->a_ops->readpage(file, page);
> page_cache_release(page);
>
> if (!error || error == AOP_TRUNCATED_PAGE)
> goto retry_find;
>
> The comment doesn't seem to match what the it actually does: if
> ->readpage() is asynchronous, then this will just repeat everything,
> without any guarantee that it will re-read once.
This patch fixes it. It's probably wrong in some subtle way though...
Miklos
---
mm/filemap.c | 6 ++++++
1 file changed, 6 insertions(+)
Index: linux.git/mm/filemap.c
===================================================================
--- linux.git.orig/mm/filemap.c 2008-05-08 08:17:22.000000000 +0200
+++ linux.git/mm/filemap.c 2008-05-08 08:19:59.000000000 +0200
@@ -1461,6 +1461,12 @@ page_not_uptodate:
*/
ClearPageError(page);
error = mapping->a_ops->readpage(file, page);
+ if (!error && !PageUptodate(page)) {
+ lock_page(page);
+ if (!PageUptodate(page))
+ error = -EIO;
+ unlock_page(page);
+ }
page_cache_release(page);
if (!error || error == AOP_TRUNCATED_PAGE)
--
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