xfs_fsr for directories?

[Bernhard Erdmann <be@xxxxxxxxxxx>]

Hi,

I've noticed on old and heavily used XFS filesystems (Newsspool oder 
Cyrus IMAP storage) even a "ls" command can take a very long time when 
there have been 10,000 to 50,000 files in a directory. "ls" spits out 
the remaining 5,000 filenames but then it sits and waits for several 
seconds (5-20 sec).

# xfs_db -r -c "frag -d" /dev/vg1/news
actual 4644, ideal 1891, fragmentation factor 59.28%
# xfs_db -r -c "frag -d" /dev/vg1/imap
actual 2299, ideal 424, fragmentation factor 81.56%

xfs_fsr cleans up the files, but who cares about directories?

How does XFS handle directories when files are deleted? Do they shrink 
as well?