bug#15328: Bug or dubious feature? (coreutils consistency prob)

[Linda Walsh]

Linda Walsh wrote:
> Whatever the problem is, it's not in 'mv'...
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        But there is a consistency problem in core utils.

Even though /usr/share/fonts and /home/share/fonts are the same directory
with /home/share being mounted with "rbind" on /usr/share,

"mv" cannot move files between the two dirs without copying them.  That
"might" be ok, except that "du -sh /usr/share/fonts /home/share/fonts/"
sees them as 1 directory.

Why does "mv" fail to rename (vs. physical copy) when "du" sees them
as the same directory -- (and only lists the first one if trying to du both):

  Ishtar:/> du -sh /home/share/fonts/. /usr/share/fonts/.
  8.8G    /home/share/fonts/.
  Ishtar:/> du -sh /usr/share/fonts/. /home/share/fonts/.
  8.8G    /usr/share/fonts/.

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Also, is it intentional to leave out args from the listing of "du" --
I know it doesn't double-count the space (by default), but I would have
thought to see a 2nd entry w/0 space:

  Ishtar:/> du -sh /home/share/fonts/. /usr/share/fonts/.
  8.8G    /home/share/fonts/.
  0       /usr/share/fonts/.