From: Mark Tinguely <tinguely@sgi.com>
To: Christoph Hellwig <hch@infradead.org>
Cc: xfs@oss.sgi.com
Subject: Re: Re: [PATCH 06/12] repair: use recursive buffer locking
Date: Fri, 13 Jan 2012 14:10:46 -0600 [thread overview]
Message-ID: <4F108FC6.60901@sgi.com> (raw)
In-Reply-To: <20111218225445.GB20578@infradead.org>
On 01/-10/63 13:59, Christoph Hellwig wrote:
> On Tue, Dec 13, 2011 at 01:22:08PM +1100, Dave Chinner wrote:
>>> if (use_xfs_buf_lock) {
>>> - if (flags& LIBXFS_GETBUF_TRYLOCK) {
>>> - int ret;
>>> + int ret;
>>>
>>> - ret = pthread_mutex_trylock(&bp->b_lock);
>>> - if (ret) {
>>> - ASSERT(ret == EAGAIN);
>>> - cache_node_put(libxfs_bcache, (struct cache_node *)bp);
>>> - return NULL;
>>> + ret = pthread_mutex_trylock(&bp->b_lock);
>>> + if (ret) {
>>> + ASSERT(ret == EAGAIN);
>>> + if (flags& LIBXFS_GETBUF_TRYLOCK)
>>> + goto out_put;
>>> +
>>> + if (pthread_equal(bp->b_holder, pthread_self())) {
>>> + fprintf(stderr,
>>> + _("recursive buffer locking detected\n"));
>>
>> "Warning: recursive buffer locking @ bno %lld detected"
>>
>> might be more informative, especially to do with the severity of the
>> issue.
>
> Ok, I'll make it print the block number.
>
>>
>>> + bp->b_recur++;
>>> + } else {
>>> + pthread_mutex_lock(&bp->b_lock);
>>> }
>>> - } else {
>>> - pthread_mutex_lock(&bp->b_lock);
>>> }
>>> +
>>> + bp->b_holder = pthread_self();
>>
>> That should probably only be written in the branch where the lock is
>> taken not every time through here.
>
> We actually should return the buffer just after incrementing the
> recursion count, else we might add it to the global list of buffers
> twice.
>
>
I liked the patch the way it was.
I thought the placement of the setting of b_holder is correct because it
covers the pthread_mutex_trylock and the pthread_mutex_lock attempts.
I did not see anything in cache_node_get_priority() nor
cache_node_set_priority() that would add this to a list.
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
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next prev parent reply other threads:[~2012-01-13 20:10 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-12-02 17:46 [PATCH 00/12] xfs_repair queue Christoph Hellwig
2011-12-02 17:46 ` [PATCH 01/12] repair: do not walk the unlinked inode list Christoph Hellwig
2011-12-12 22:55 ` Dave Chinner
2012-01-12 19:30 ` Mark Tinguely
2011-12-02 17:46 ` [PATCH 02/12] repair: allocate and free inode records individually Christoph Hellwig
2011-12-12 23:16 ` Dave Chinner
2012-01-12 22:38 ` Mark Tinguely
2011-12-02 17:46 ` [PATCH 03/12] repair: allocate and free extent " Christoph Hellwig
2011-12-12 23:21 ` Dave Chinner
2012-01-12 22:39 ` Mark Tinguely
2011-12-02 17:46 ` [PATCH 04/12] xfsprogs: allow linking against libtcmalloc Christoph Hellwig
2011-12-13 0:05 ` Dave Chinner
2011-12-18 22:47 ` Christoph Hellwig
2011-12-02 17:46 ` [PATCH 05/12] repair: update extent count after zapping duplicate blocks Christoph Hellwig
2011-12-13 2:12 ` Dave Chinner
2012-02-02 12:39 ` [PATCH v2] " Christoph Hellwig
2012-02-02 18:19 ` Mark Tinguely
2012-01-13 17:18 ` [PATCH 05/12] " Mark Tinguely
2011-12-02 17:46 ` [PATCH 06/12] repair: use recursive buffer locking Christoph Hellwig
2011-12-13 2:22 ` Dave Chinner
2011-12-18 22:54 ` Christoph Hellwig
2012-01-13 20:10 ` Mark Tinguely [this message]
2011-12-02 17:46 ` [PATCH 07/12] repair: fix another ABBA deadlock in inode prefetching Christoph Hellwig
2011-12-13 2:35 ` Dave Chinner
2012-01-13 18:51 ` Mark Tinguely
2011-12-02 17:46 ` [PATCH 08/12] repair: handle filesystems with the log in allocation group 0 Christoph Hellwig
2011-12-13 2:36 ` Dave Chinner
2012-01-13 15:18 ` Mark Tinguely
2011-12-02 17:46 ` [PATCH 09/12] repair: kill check_inode_block Christoph Hellwig
2012-01-11 11:29 ` Christoph Hellwig
2012-01-11 21:28 ` Mark Tinguely
2011-12-02 17:46 ` [PATCH 10/12] repair: mark local functions static Christoph Hellwig
2012-01-11 11:30 ` Christoph Hellwig
2012-01-11 21:37 ` Mark Tinguely
2011-12-02 17:46 ` [PATCH 11/12] repair: move extern declarations to headers Christoph Hellwig
2012-01-11 11:30 ` Christoph Hellwig
2012-01-11 21:40 ` Mark Tinguely
2011-12-02 17:46 ` [PATCH 12/12] repair: cleanup inode record macros Christoph Hellwig
2012-01-11 11:30 ` Christoph Hellwig
2012-01-12 17:05 ` Mark Tinguely
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