Re: [PATCH 1/3] mds: update atime if client can read.

From: Sage Weil
Date: Tue Jul 02 2013 - 12:48:26 EST


On Tue, 2 Jul 2013, majianpeng wrote:
> Now, update atime only for CEPH_CAP_FILE_EXCL.Change this if
> CEPH_CAP_FILE_RD.

Can we introduce a global config optoin (bool mds_atime in
common/config_opts.h, maybe) so that users can turn this off? And/or add
a 'relatime' option? More users won't want this as it is very expensive
to maintain this extra level of metadata.

That aside, this approach looks right to me. :)

Thanks!
sage


>
> Signed-off-by: Jianpeng Ma <majianpeng@xxxxxxxxx>
> ---
> src/mds/Locker.cc | 15 +++++++++------
> 1 file changed, 9 insertions(+), 6 deletions(-)
>
> diff --git a/src/mds/Locker.cc b/src/mds/Locker.cc
> index 30e014a..58f953f 100644
> --- a/src/mds/Locker.cc
> +++ b/src/mds/Locker.cc
> @@ -2676,8 +2676,9 @@ void Locker::_do_snap_update(CInode *in, snapid_t snap, int dirty, snapid_t foll
> void Locker::_update_cap_fields(CInode *in, int dirty, MClientCaps *m, inode_t *pi)
> {
> // file
> + utime_t atime = m->get_atime();
> +
> if (dirty & (CEPH_CAP_FILE_EXCL|CEPH_CAP_FILE_WR)) {
> - utime_t atime = m->get_atime();
> utime_t mtime = m->get_mtime();
> utime_t ctime = m->get_ctime();
> uint64_t size = m->get_size();
> @@ -2700,11 +2701,7 @@ void Locker::_update_cap_fields(CInode *in, int dirty, MClientCaps *m, inode_t *
> pi->size = size;
> pi->rstat.rbytes = size;
> }
> - if ((dirty & CEPH_CAP_FILE_EXCL) && atime != pi->atime) {
> - dout(7) << " atime " << pi->atime << " -> " << atime
> - << " for " << *in << dendl;
> - pi->atime = atime;
> - }
> +
> if ((dirty & CEPH_CAP_FILE_EXCL) &&
> ceph_seq_cmp(pi->time_warp_seq, m->get_time_warp_seq()) < 0) {
> dout(7) << " time_warp_seq " << pi->time_warp_seq << " -> " << m->get_time_warp_seq()
> @@ -2712,6 +2709,12 @@ void Locker::_update_cap_fields(CInode *in, int dirty, MClientCaps *m, inode_t *
> pi->time_warp_seq = m->get_time_warp_seq();
> }
> }
> +
> + if ((dirty & CEPH_CAP_FILE_RD) && atime > pi->atime) {
> + dout(7) << " atime " << pi->atime << " -> " << atime
> + << " for " << *in << dendl;
> + pi->atime = atime;
> + }
> // auth
> if (dirty & CEPH_CAP_AUTH_EXCL) {
> if (m->head.uid != pi->uid) {
> --
> 1.8.3.rc1.44.gb387c77
>
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