On Thu, Dec 15, 2016 at 12:21:43PM -0600, Eric Sandeen wrote: > On 12/6/16 9:47 PM, Dave Chinner wrote: > > From: Dave Chinner <dchinner@xxxxxxxxxx> > > > > It makes no sense to iterate the file table for some xfs_io > > commands. Some commands are already marked in this way, but lots of > > them are not and this leads to bad behaviour. For example, the open > > command will run until the process fd table is full and EMFILE is > > returned rather than just opening the specified file once. > > Ok, I'm not quite clear on when we should expect commands to be > "oneshot" > > With freeze, for example, this: > > xfs_io -x -c freeze mnt/file mnt2/file > > will freeze both filesystems today. With this change, xfs_freeze will ignore multiple filesystem options, so it only ever passes a single file to xfs_io. IOWs, it's behaviour will be completely unchanged by making the xfs_io freeze command a one-shot command. And right now, I think that's the only case we have to care about. unless someone is actually using xfs_io directly to freeze multiple filesystems like this, then I think it's better to make it a one-shot command. > xfs_io -x -c freeze mnt/file mnt2/file > > freezes the mnt2 filesystem but not mnt. Is that desired? It's exactly what the man page says the freeze command does. > I guess the command /is/ documented as "freeze fs of /current/ file" > but i wonder if that's just an accident of documentation. If the man page documents it as operating on the current file, but instead it freezes all the open files, then that's a bug that needs fixing. > ditto for i.e. the inode command, or resblks - why not > iterate those? Because they are aimed at single, specific filesystem operations only. It just doesn't make sense to iterate them across all open files inside xfs_io. If you have multiple filesystems youneed to query/modify, then do an xfs_io call for each. Cheers, Dave. -- Dave Chinner david@xxxxxxxxxxxxx -- To unsubscribe from this list: send the line "unsubscribe linux-xfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
