From: Miklos Szeredi <mszeredi@suse.cz>
Date: Fri, 4 Jul 2008 07:35:17 +0000 (+0200)
Subject: splice: fix generic_file_splice_read() race with page invalidation
X-Git-Tag: v2.6.27-rc1~1114^2
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=32502b8413a77b54b9e19809404109590c32dfb7;p=pandora-kernel.git

splice: fix generic_file_splice_read() race with page invalidation

If a page was invalidated during splicing from file to a pipe, then
generic_file_splice_read() could return a short or zero count.

This manifested itself in rare I/O errors seen on nfs exported fuse
filesystems.  This is because nfsd uses splice_direct_to_actor() to read
files, and fuse uses invalidate_inode_pages2() to invalidate stale data on
open.

Fix by redoing the page find/create if it was found to be truncated
(invalidated).

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
---

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