On Mon, Dec 5, 2016 at 4:19 PM, Eric Sandeen <sandeen@xxxxxxxxxxx> wrote: > On 12/5/16 7:03 AM, Amir Goldstein wrote: >> There is an undocumented and possibly unused feature in xfs_io >> where all commands are executed per file in the file args list. >> >> This feature creates ambiguity when trying to execute commands >> such as "open" and "file" from command line and result in an >> endless loop in the command loop code. > > I may well be dense, but it's not immediately obvious what the > old and/or problematic behavior is. Can you spell it out a bit > more? What is an example of this loop? $ touch foo $ xfs_io -c "open foo" foo you will see the shit storm > >> Also, when running xfs_io -c <cmd> without any file args, xfs_io >> exits without doing anything. This behavior is also undocumented >> and makes very little sense. > > What /should/ it do if there is no file specified? Is this just for > cmds that don't require a file, such as "-c sync?" Execute the commands as if you ran xfs_io and entered those commands in the shell, for example: $ xfs_io -c "open foo" -c "pread -v 0 4" > >> Change the behavior of xfs_io to execute each command specified >> with -c <cmd> exactly once, regardless of the number of files in >> the file args list. > > So then which file does it act on? I'm not saying this is incorrect, > I'm just not quite understanding what this fixes, and what the new > behavior is, sorry. > You are not to be blamed for not knowing what the old behavior is it is undocumented and I have never seen it used in tests. Old behavior of $ xfs_io -c -c "pread -v 0 4" -c "pread -v 4 8" foo bar - print 0..4 from foo - print 4..8 from foo - print 0..4 from bar - print 4..8 from bar New behavior is: - print 0..4 from bar (the "current" file) - print 4..8 from bar Same behavior as when you issue the same command after running $ xfs_io foo bar Amir. -- 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
