bin/124424: [zfs] zfs list -r shows strange snapshots' size

[Anatoly Borodin]

>Number:         124424
>Category:       bin
>Synopsis:       [zfs] zfs list -r shows strange snapshots' size
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Mon Jun 09 17:10:05 UTC 2008
>Closed-Date:
>Last-Modified:
>Originator:     Anatoly Borodin
>Release:        FreeBSD 7.0-STABLE
>Organization:
>Environment:
FreeBSD fractal.home 7.0-STABLE FreeBSD 7.0-STABLE #0: Wed Jun  4 21:40:37 EEST 2008     anatoly.borodin at gmail.com:/usr/obj/usr/src/sys/GENERIC  i386
>Description:
tank/storage/unsorted/TODO contains some snapshots, which contained no data since this filesystem was unchanged for a while. Now some big files were removed (~1.8G), and zfs doesn't show the space occupied by snapshots until the only one snapshot is left. The user can see 5.27G and 3.45G numbers, but cannot see 1.8G number until then.

root at fractal.home[1]:~>zfs destroy tank/storage/unsorted/TODO at UTC_20080602_1109
Mon Jun  9 19:42:06 EEST 2008
root at fractal.home[1]:~>zfs list -r tank/storage/unsorted/TODO
NAME                                           USED  AVAIL  REFER  MOUNTPOINT
tank/storage/unsorted/TODO                    5.27G  61.6G  3.45G  /storage/unsorted/TODO
tank/storage/unsorted/TODO at UTC_20080602_1114      0      -  5.27G  -
tank/storage/unsorted/TODO at UTC_20080603_2358      0      -  5.27G  -
tank/storage/unsorted/TODO at UTC_20080604_1911      0      -  5.27G  -
tank/storage/unsorted/TODO at UTC_20080606_1822      0      -  5.27G  -
tank/storage/unsorted/TODO at UTC_20080606_1824      0      -  5.27G  -
tank/storage/unsorted/TODO at UTC_20080609_1019      0      -  5.27G  -
Mon Jun  9 19:42:14 EEST 2008
root at fractal.home[1]:~>zfs destroy tank/storage/unsorted/TODO at UTC_20080602_1114
Mon Jun  9 19:42:28 EEST 2008
root at fractal.home[1]:~>zfs destroy tank/storage/unsorted/TODO at UTC_20080603_2358
Mon Jun  9 19:42:41 EEST 2008
root at fractal.home[1]:~>zfs destroy tank/storage/unsorted/TODO at UTC_20080604_1911
Mon Jun  9 19:42:47 EEST 2008
root at fractal.home[1]:~>zfs list -r tank/storage/unsorted/TODO
NAME                                           USED  AVAIL  REFER  MOUNTPOINT
tank/storage/unsorted/TODO                    5.27G  61.6G  3.45G  /storage/unsorted/TODO
tank/storage/unsorted/TODO at UTC_20080606_1822      0      -  5.27G  -
tank/storage/unsorted/TODO at UTC_20080606_1824      0      -  5.27G  -
tank/storage/unsorted/TODO at UTC_20080609_1019      0      -  5.27G  -
Mon Jun  9 19:42:51 EEST 2008
root at fractal.home[1]:~>zfs destroy tank/storage/unsorted/TODO at UTC_20080606_1822
Mon Jun  9 19:42:58 EEST 2008
root at fractal.home[1]:~>zfs destroy tank/storage/unsorted/TODO at UTC_20080606_1824
Mon Jun  9 19:43:05 EEST 2008
root at fractal.home[1]:~>zfs list -r tank/storage/unsorted/TODO
NAME                                           USED  AVAIL  REFER  MOUNTPOINT
tank/storage/unsorted/TODO                    5.27G  61.6G  3.45G  /storage/unsorted/TODO
tank/storage/unsorted/TODO at UTC_20080609_1019  1.82G      -  5.27G  -
Mon Jun  9 19:43:07 EEST 2008

>How-To-Repeat:

>Fix:


>Release-Note:
>Audit-Trail:
>Unformatted: