Zygo

> Provided nothing else is keeping the file open, lazytime is not reducing atime updates to disk that much more than relatime alone would, given the find / bulk read...

I think it's a good summary, but it's mostly summarizing stuff I wrote, so I'm biased. ;)

So I tried to fix this, and it's bugs all the way down: * `parse_mntinfo_line` parses a /proc/self/mountinfo line that has a fixed number of fields, but `mountinfo` has a...

Normally, drive firmware handles UNC sectors by giving IO error on read, and remapping the write to an alternate reserved sector on write. So all you have to do is...

The man page says: > Start a scrub on all devices of the mounted filesystem identified by path or on a single device. Do you have a suggested rewording to...

"Referenced" counts the number of times each reference is seen in the files named on the command line. It doesn't tell you whether the underlying extents are shared. It doesn't...

> On the other hand, using max_object beyond the st_ino, makes it slower by ~11%, on the same filesystem. That's interesting. Any idea why? Hmmm...maybe the other max_ fields should...

That would be: min = (st_ino, BTRFS_EXTENT_DATA_KEY, 0), max = (st_ino + 1, BTRFS_INODE_ITEM_KEY, 0) That should make the search stop as soon as it finds the next inode, without...

The worst case on modern btrfs is only 32768x expansion (128M max extent, 4K referenced). The 1GB-4K case is only possible with a filesystem written before the extent size limit...

Unreferenced can be calculated for compressed extents, but only on the uncompressed size where a block boundary makes any kind of sense. It could be approximated, but probably not worth...