staging/lustre/llite: take trunc_sem only at vvp layer
authorPatrick Farrell <paf@cray.com>
Mon, 20 Jun 2016 20:55:35 +0000 (16:55 -0400)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Mon, 20 Jun 2016 21:28:39 +0000 (14:28 -0700)
commit0e5fd06ca069a8edc32a035add93112f6681dd72
treeefdf6e7c7b0d8b2fdd751157a03d8edfe8bf5d1a
parent81ea39ecf963fe0c44b8772a19863ecb154782f6
staging/lustre/llite: take trunc_sem only at vvp layer

The lli_trunc_sem is taken in 'read' mode in both
ll_page_mkwrite and vvp_io_fault_start. This can lead to a
deadlock with another thread which asks for the semaphore
in write mode between thse two read calls.

Since all users of lli_trunc_sem are in the vvp layer, we
can satisfy the requirement to exclude truncate by taking
the semaphore only in vvp_io_fault_start.

Signed-off-by: Patrick Farrell <paf@cray.com>
Reviewed-on: http://review.whamcloud.com/19315
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-7981
Reviewed-by: Jinshan Xiong <jinshan.xiong@intel.com>
Reviewed-by: Andriy Skulysh <andriy.skulysh@seagate.com>
Signed-off-by: Oleg Drokin <green@linuxhacker.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/staging/lustre/lustre/llite/llite_mmap.c