I think one should only be able to set a subset of the flags and have other flags such as O_RDWR and O_LARGEFILE always be set. Otherwise someone might try to create a readonly lun by setting O_RDONLY instead of O_RDWR and while it will not be possible to write to the LUN, this would break on the initiator side since true readonly would require a bit more than failing to write. (such as different data in mode sense as well as specific sense codes when refusing a write) regards ronnie sahlberg On Thu, Apr 22, 2010 at 7:44 AM, Mike Anderson <andmike@xxxxxxxxxxxxxxxxxx> wrote: > Chandra Seetharaman <sekharan@xxxxxxxxxx> wrote: >> >> On Wed, 2010-04-21 at 19:51 +1000, ronnie sahlberg wrote: >> > >> > >> > Tomo, would a patch that allows setting the O_DIRECT/O_SYNC flags on >> > the command line when invoking tgtd be acceptable? >> > >> > >> > >> > >> > tgtd -o O_SYNC tgtd -o O_DIRECT tgtd -o O_SYNC|O_DIRECT >> > >> > >> > >> > The appropriate flags in the caching mode page could be intercepted >> > and use to toggle these fd settings. >> > >> > My filesystem of choice would likely benefit greatly from O_DIRECT. >> >> I see the feature being useful. >> >> But, I would associate this to be a characteristic of the backing store >> than set it globally at tgtd (or we can have a it at global(read tgtd >> level) and ability to revert it at the backing store). >> > > > If we associate the open flags to the backing store would we want to allow > full control of the open flags or just setting a subset of flags. > > I hacked up tgtadm and a few of the target.c functions for the examples below. > > ./tgtadm --lld iscsi --op new --mode logicalunit --tid 1 --lun 1 -b /disk1 > --bsoflags "O_RDWR| O_LARGEFILE | O_DIRECT" --device-type disk > > or > > tgtadm --op update --mode logicalunit --tid 1 --lun 1 --params bsoflags="O_RDWR| O_LARGEFILE | O_DIRECT" > > ./tgtadm --op show --mode target > ... > LUN: 1 > Type: disk > SCSI ID: IET 00010001 > SCSI SN: beaf11 > Size: 105 MB > Online: Yes > Removable media: No > Backing store type: rdwr > Backing store flags: O_RDWR | O_LARGEFILE | O_DIRECT > Backing store path: /disk1 > ... > > -andmike > -- > Michael Anderson > andmike@xxxxxxxxxxxxxxxxxx > -- To unsubscribe from this list: send the line "unsubscribe stgt" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
