From: Yongqiang Yang <xiaoqiangnk@gmail.com>
Date: Wed, 27 Jul 2011 01:35:44 +0000 (-0400)
Subject: ext4: prevent parallel resizers by atomic bit ops
X-Git-Tag: v3.1-rc1~90^2~21
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=8f82f840ec6ab873f520364d443ff6fa1b3f8e22;p=pandora-kernel.git

ext4: prevent parallel resizers by atomic bit ops

Before this patch, parallel resizers are allowed and protected by a
mutex lock, actually, there is no need to support parallel resizer, so
this patch prevents parallel resizers by atmoic bit ops, like
lock_page() and unlock_page() do.

To do this, the patch removed the mutex lock s_resize_lock from struct
ext4_sb_info and added a unsigned long field named s_resize_flags
which inidicates if there is a resizer.

Signed-off-by: Yongqiang Yang <xiaoqiangnk@gmail.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
---

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