On Wed, Dec 06, 2017 at 04:01:58PM -0600, Eric Sandeen wrote: > On 12/6/17 3:57 PM, Dave Chinner wrote: > > > There's a *simple answer* to this problem: fix the new command's > > output. > > > > That is: the user asked for a specific range, so the command itself > > should trim the map returned by the kernel to only display the exact > > range the user asked for. Then it doesn't matter if the underlying > > filesystem trims the extents or not, because the we're going to do > > that anyway in userspace. > > I have a different opinion: > > xfs_io is a debugging tool; the fiemap command sends an ioctl to the kernel. > > Ranged fiemap queries are a real thing; you put numbers into the kernel, > and you get numbers out of the kernel. > > IMNSO, xfs_io should present to the user /what the kernel returned/, > and not re-interpret it to fit some other notion of correctness if we > don't like what the kernel told us. I hardly think "trimming to the range the user asked for" is "re-interpreting what the kernel told us". It's limiting output range to exactly what the user asked for - the output is still correct regardless of how it's filtered to match what the user asked for.... > If you want to have some user-friendlier behavior where xfs_io layers > behaviors on top of what the kernel provides, then add a "-t" argument for trim, > but hiding ioctl inconsistencies by filtering them through xfs_io sounds > like the wrong approach to me. Just filter the last output in the test, then, so it looks like 2: [128..XXX] data There is absolutely no excuse for creating multiple tests to support a small difference in trailing extent range output from different filesystem. 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
