Dave Jones <davej@redhat.com> writes:

> On Thu, Oct 16, 2014 at 10:33:46AM -0400, Dave Jones wrote:
>
>  >  > Try this patch http://www.spinics.net/lists/linux-ext4/msg45683.html
>  > 
>  > I'll give it a try if I can get it reproducing easily, otherwise I cna't say
>  > either way whether the patch is doing any good.
>
> ok, I managed to reproduce it a few times, and then tried again with
> your patch.  I'm not sure if it's related, but I'm now seeing lockups
> in ext4.  The process that gets stuck looks like this..
99.99% this one is not related. This is just one more uncovered one
by trinity magics. Looks like I've got what is wrong
lseek SEEK_HOLE/SEEK_DATA try to find block allocated one by one
instead of using ext4_ext_next_allocated_block() COMMIT c8c0df24
Plese look an my test below. I'm too tired for today (especially
after Gone girl the movie). I'll send patch tomorrow.
>
> trinity-c21     R  running task    13232  9781    831 0x10000004
>  0000000000000000 0000000000000001 0000000000000000 0000000000000000
>  ffff8800c8d333d8 0000000000000000 0000000000000002 00000000cacaa650
>  ffff880217cf7db8 0000000000000000 0000000000000000 ffffffffa929ff8c
> Call Trace:
>  [<ffffffffa929ff8c>] ? ext4_map_blocks+0x31c/0x560
>  [<ffffffffa929fe75>] ? ext4_map_blocks+0x205/0x560
>  [<ffffffffa92e689c>] ? ext4_es_find_delayed_extent_range+0x48c/0x4e0
>  [<ffffffffa9298fe1>] ? ext4_llseek+0x261/0x3f0
>  [<ffffffffa922e6e9>] ? __fdget_pos+0x49/0x50
>  [<ffffffffa90e484e>] ? rcu_read_lock_held+0x6e/0x80
>  [<ffffffffa920ca44>] ? SyS_lseek+0x94/0xc0
>
> I've got to run right now, but I'll look into tracing it some more when I get back.
>
> 	Dave