Even more than that, the locks also control metadata trimming and things. You might actually crash the server, not "merely" get inconsistent results back! -Greg On Sat, Feb 10, 2018 at 9:53 AM, John Spray <jspray@xxxxxxxxxx> wrote: > (cut down CC list to ceph-devel) > > If you skip taking locks, then you will be serving the client stale > metadata, and breaking the ordinary consistency rules for POSIX file > IO. That might be what you want if you have a special application and > you want a specially hacked MDS to run it faster, but if you are > running an application that expects a filesystem to behave correctly > then it would be hard to predict the ways in which it could break. > > John > > On Sat, Feb 10, 2018 at 8:15 AM, Mark Meyers <MarkMeyers.MMY@xxxxxxxxx> wrote: >> I found ls command costs extremely long time (form 30s to 3mins). >> So I tried to remove acquire_locks in mds's getattr handler: handle_clinet_getattr. >> Everything looks just good: >> First, the size of files get updated in time. >> Second, the read and write to file from clinets works ok. >> >> So, please, can I just omiit acquire_locks in mds getattr handler?(if client request doesn't requier or have Fwb caps) >> >> Code: >> >> diff -- git a/src/mds/Server.cc n/src/mds/Server.cc >> >> --- a/src/mds/Server.cc >> +++ b/src/mds/Server.cc >> @@ -3021,7 +3021,10 @@ void Server::handler_client_getattr(MDRequestRef& mdr, bool is_lookup) >> if ((mask & CEPH_CAP_FILE_SHARED) && (issued & CEPH_CAP_FILE_EXCL) == 0) rdlocks.insert(&ref->filelock); >> if ((mask & CEPH_CAP_XATTR_SHARED) && (issued & CEPH_CAP_XATTR_EXCL) == 0) rdlocks.insert(&ref->xattrlock); >> - if (!mds->locker->acquire_locks(mdr, rdlocks, wrlocks, xlocks)) >> + dout(20) << __func__ << " mask " << ccap_string(mask) << " issued " << >> ccap_string(issued) << " " << !is_lookup << " ." << dendl; >> + if(!(mask & CEPH_CAP_FILE_WR) && !(mask & CEPH_CAP_FILE_BUFFER) && !(issued & CEPH_CAP_FILE_WR) && !(iissued & CEPH_CAP_FILE_BUFFER) && !is_lookup) >> + dout(10) << "no Fw/b in mask " << ccap_string(mask) << " or issued " << ccap_string(issued) << " " << !is_lookup << " ." << dendl;+ else if (!mds->locker->acquire_locks(mdr, rdlocks, wrlocks, xlocks)) >> return; >> >> >> if (!check_access(mdr, ref, MAY_READ)) >> -- >> To unsubscribe from this list: send the line "unsubscribe ceph-devel" in >> the body of a message to majordomo@xxxxxxxxxxxxxxx >> More majordomo info at http://vger.kernel.org/majordomo-info.html > -- > To unsubscribe from this list: send the line "unsubscribe ceph-devel" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
