Dave Jones <davej@xxxxxxxxxx> 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
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/* * regression test for bug in ext4_seek_data * (C) Dmitry Monakhov * original report https://lkml.org/lkml/2014/10/16/620 */ #define _GNU_SOURCE #define _LARGEFILE_SOURCE #define _FILE_OFFSET_BITS 64 #include <sys/types.h> #include <unistd.h> #include <fcntl.h> #ifndef SEEK_DATA #define SEEK_DATA 3 #endif int main(int argc, char **argv) { int fd; loff_t size = 1ULL << 40; fd = open("test", O_RDWR|O_CREAT, 0777); ftruncate(fd, size); size = 1ULL << 39; /* Next line will likely spin forever :) */ llseek(fd, size, SEEK_DATA); return 0; }
