From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jens Axboe Subject: Re: [PATCH] Fix balance Oops Date: Fri, 7 Aug 2009 09:19:52 +0200 Message-ID: <20090807071952.GS12579@kernel.dk> References: <4A7BC631.3040106@oracle.com> <20090807065039.GR12579@kernel.dk> <4A7BD4B0.2080104@oracle.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-btrfs@vger.kernel.org, Chris Mason To: Yan Zheng Return-path: In-Reply-To: <4A7BD4B0.2080104@oracle.com> List-ID: On Fri, Aug 07 2009, Yan Zheng wrote: > On 08/07/2009 02:50 PM, Jens Axboe wrote: > > On Fri, Aug 07 2009, Yan Zheng wrote: > >> invalidate_inode_pages2_range may return -EBUSY occasionally > >> which results Oops. This patch fixes the issue by moving > >> invalidate_inode_pages2_range into a loop and keeping calling > >> it until the return value is not -EBUSY. > >> > >> Signed-off-by: Yan Zheng > >> > >> --- > >> diff -urp 1/fs/btrfs/relocation.c 2/fs/btrfs/relocation.c > >> --- 1/fs/btrfs/relocation.c 2009-07-29 10:03:04.367858774 +0800 > >> +++ 2/fs/btrfs/relocation.c 2009-08-07 13:26:43.882147138 +0800 > >> @@ -2553,8 +2553,13 @@ int relocate_inode_pages(struct inode *i > >> last_index = (start + len - 1) >> PAGE_CACHE_SHIFT; > >> > >> /* make sure the dirty trick played by the caller work */ > >> - ret = invalidate_inode_pages2_range(inode->i_mapping, > >> - first_index, last_index); > >> + while (1) { > >> + ret = invalidate_inode_pages2_range(inode->i_mapping, > >> + first_index, last_index); > >> + if (ret != -EBUSY) > >> + break; > >> + cond_resched(); > >> + } > > > > If it returns EBUSY, would it not make more sense to call > > filemap_write_and_wait_range() instead of hammering on invalidate? > > > > The pages to invalidate are not dirty, they are from page read-ahead. > Actually I have no idea how invalidate_inode_pages2_range can return > -EBUSY here. (the only user of the inode is the balancer, and it does > not hold references to the pages) Weird, I looked it up, and it already does a writeback wait. But I guess that's not your issue. Patch still looks like a hack though, it would be far better to figure out why it returns EBUSY and fix/wait appropriately for that to pass. -- Jens Axboe