Too small arrays for file names

Too small arrays for file names

In our experiments blktrace/blkparse file names encode a lot of
infomation about the particular experiment.  We noticed that for long
enough file names blkparse does not work.

The reason is that per_cpu_info->fname[] is of 128 bytes. As a result,
in setup_file() function only part of the file name gets to ->fname[].
Then stat() fails and we exit the function. Notice, that no error is
printed in this case.

In the following patch ->fname[] size is increased to POSIX defined
PATH_MAX.

Signed-off-by: Vasily Tarasov <tarasov@vasily.name
Signed-off-by: Jens Axboe <axboe@kernel.dk>