On 8/21/13 2:37 PM, Eric Sandeen wrote: > On 8/21/13 2:20 PM, Mark Tinguely wrote: >> On 08/21/13 13:31, Eric Sandeen wrote: > > ... > >>>> There are different versions of XFS seek_data and they will >>>> detect/report the start of data and holes differently so output >>>> parsing will be a bear. The existing C code sends the 2 different >>>> value numbers that could be reported. >>> >>> are they ... both correct? If one is a bug, it can just be a bug, right? >>> I'm sorry I'm not up on the history. >> >> Lets say we have a file >> hole 0-4K >> data 4K-8K >> hole 8-12K >> data 12-16K >> >> for data/hole check starting at offset 0, valid response are >> 0K or 4K for data >> 0K or 16K or -1 for holes >> >> This feature and test was for Jeff fine-tuned seek_data/seek_hole support. The tests would be more specific to that feature and output is specific. > > Well, at least the man page says: > >> SEEK_DATA >> Adjust the file offset to the next location in the file greater than >> or equal to offset containing data. If offset points to data, then >> the file offset is set to offset. > > So above, if we say "SEEK_DATA at offset 0" it seems like 0k is clearly wrong, and 4k is clearly right. > >> SEEK_HOLE >> Adjust the file offset to the next hole in the file greater than or >> equal to offset. If offset points into the middle of a hole, then the >> file offset is set to offset. If there is no hole past offset, then >> the file offset is adjusted to the end of the file (i.e., there is an >> implicit hole at the end of any file). > > and "SEEK_HOLE at offset 0" should pretty clearly return 0, and 16k would be wrong. > > It's not POSIX yet, so I guess there's no gospel, but that's what the man page says. though I see the seek sanity test has all kinds of exceptions. Yuck. So back to: Just report what lseek says, and leave interpretation to the caller. ;) -Eric > -Eric > > _______________________________________________ > xfs mailing list > xfs@xxxxxxxxxxx > http://oss.sgi.com/mailman/listinfo/xfs > _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
