Re: Process hangs on blk_congestion_wait copying large file tocifs filesystem

[Nuno Ferreira]

On Sex, 2004-05-28 at 16:22 +0200, Jens Axboe wrote:
> On Fri, May 28 2004, Nuno Ferreira wrote:
> > On Qui, 2004-05-27 at 16:45 +0100, Nuno Ferreira wrote:
> > > Hi,
> > > I'm trying to copy a large file (200Mb or bigger) from an ext3
> > > filesystem to a windows share mounted using CIFS and the cp process
> > > hangs, sometimes for a long time (several minutes).
> > > Calling ps, I can see that it's blocking on blk_congestion_wait. 
[...]
> 
> A sysrq-t back trace of that process would be interesting to see.

OK, apparently now the cp never finishes and nothing gets written to
disk, so i could not get the full output from sysrq-t.
I wrote the call stack from the process, it that enough?
The call stack from the cp process:
__make_request
schedule_timeout
process_timeout
io_schedule_timeout
blk_congestion_wait
autoremove_wake_function
autoremove_wake_function
get_dirty_limits
balance_dirty_pages
generic_file_aio_write_nolock
__copy_to_user_ll
file_read_actor
__generic_file_aio_read
file_read_actor
generic_file_write_nolock
do_sync_read
do_IRQ
common_interrupt
generic_file_write
cifs_write_wrapper
do_sync_read
vfs_write
sys_write
syscall_call

Also the call from a vi process that was called after the cp reached
that state and was also blocked
schedule_timeout
ext3_mark_inode_dirty
process_timeout
io_schedule_timeout
blk_congestion_wait
autoremove_wake_function
get_dirty_limits
balance_dirty_pages
generic_file_aio_write_nolock
buffered_rmqueue
__alloc_pages
generic_file_aio_write
ext2_file_write
do_sync_write
do_lookup
path_release
sys_access
vfs_write
sys_write
syscall_call

If more detail is needed I can try to capture it but syslog not writing
to disk I don't know how to capture the sysrq-t output

Thanks
-- 
Nuno Ferreira

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