staging: lustre: hsm: Use file lease to implement migration
authorHenri Doreau <henri.doreau@cea.fr>
Thu, 10 Nov 2016 17:30:31 +0000 (12:30 -0500)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Mon, 14 Nov 2016 15:16:57 +0000 (16:16 +0100)
commit0ffaa9c8eb2faab0cb2dbbe46a83ec5f96df0310
tree4f621177649d7a7daab95a3c76ba5709010b8d61
parentb73d803b656e58a0bba69eff9cedd6f4e52aaba1
staging: lustre: hsm: Use file lease to implement migration

Implement non-blocking migration based on exclusive open instead of
group lock. Implemented exclusive close operation to atomically put
a lease, swap two layouts and close a file. This allows race-free
migrations.

Make the caller responsible for retrying on failure (EBUSY, EAGAIN)
in non-blocking mode.

In blocking mode, allow applications to trigger layout swaps using a
grouplock they already own, to prevent race conditions between the
actual data copy and the layout swap. Updated lfs accordingly. File
leases are also taken in blocking mode, so that lfs migrate can issue
a warning if an application attempts to open a file that is being
migrated and gets blocked.

Timestamps (atime/mtime) are set from userland, after the layout swap
is performed, to prevent conflicts with the grouplock.

lli_trunc_sem is taken/released in the vvp_io layer, under the DLM
lock. This re-ordering fixes the original issue between truncate and
migrate.

Signed-off-by: Henri Doreau <henri.doreau@cea.fr>
Signed-off-by: Jinshan Xiong <jinshan.xiong@intel.com>
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-4840
Reviewed-on: http://review.whamcloud.com/10013
Reviewed-by: John L. Hammond <john.hammond@intel.com>
Reviewed-by: frank zago <fzago@cray.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>
Signed-off-by: James Simmons <jsimmons@infradead.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/staging/lustre/lustre/include/lustre/lustre_idl.h
drivers/staging/lustre/lustre/include/lustre/lustre_user.h
drivers/staging/lustre/lustre/include/lustre_req_layout.h
drivers/staging/lustre/lustre/llite/file.c
drivers/staging/lustre/lustre/llite/llite_lib.c
drivers/staging/lustre/lustre/llite/vvp_io.c
drivers/staging/lustre/lustre/mdc/mdc_lib.c
drivers/staging/lustre/lustre/mdc/mdc_request.c
drivers/staging/lustre/lustre/ptlrpc/layout.c