Bug 224851
| Summary: | Bug in getmntinfo(3) / getfsstat(2) ? | ||||||
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| Product: | Base System | Reporter: | Jamie Landeg-Jones <jamie> | ||||
| Component: | kern | Assignee: | Edward Tomasz Napierala <trasz> | ||||
| Status: | Closed FIXED | ||||||
| Severity: | Affects Some People | CC: | jamie, trasz | ||||
| Priority: | --- | ||||||
| Version: | CURRENT | ||||||
| Hardware: | Any | ||||||
| OS: | Any | ||||||
| Attachments: |
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The referenced PR is bug #195161 : [autofs] automounted directories not being unmounted A commit references this bug: Author: trasz Date: Wed Jan 10 17:51:02 UTC 2018 New revision: 327777 URL: https://svnweb.freebsd.org/changeset/base/327777 Log: Make nullfs properly report MNT_AUTOMOUNTED set on the nullfs mount itself, instead of copying from the underlying filesystem. PR: 224851 Reported by: Jamie Landeg-Jones <jamie at dyslexicfish.net> Tested by: Jamie Landeg-Jones <jamie at dyslexicfish.net> MFC after: 2 weeks Changes: head/sys/fs/nullfs/null_vfsops.c A commit references this bug: Author: trasz Date: Mon Apr 16 17:12:19 UTC 2018 New revision: 332613 URL: https://svnweb.freebsd.org/changeset/base/332613 Log: MFC r327777: Make nullfs properly report MNT_AUTOMOUNTED set on the nullfs mount itself, instead of copying from the underlying filesystem. PR: 224851 Changes: _U stable/11/ stable/11/sys/fs/nullfs/null_vfsops.c |
Created attachment 189351 [details] test file to demonstrate the problem There appears to be a bug in the system call related to getmntinfo(3) / getfsstat(2), when if the "automount" flag is set on "nullfs" mounts, it is not returned on a getfsstat "WAIT" call. The non-refreshed, non-blocking "MNT_NOWAIT" produces the correct result. I first noticed this when debugging why my nullfs autofs partitions weren't being automatically unmounted. (FreeBSD current and release) If this is actually intended behaviour, please reassign this as something that needs to be worked around in the autofs code (I think this is similar in this regard to #195161 ) The somewhat hacked attached snippet from automount.c in the example below demonstrates this - When called with no parameters, it performs a MNT_WAIT request, otherwise a MNT_NOWAIT request is performed. The results are: | 14:24 [2] (1) "autofs" root@thompson# df | Filesystem 1K-blocks Used Avail Capacity Mounted on | /dev/ada1p2 5061628 707264 3949436 15% / | devfs 1 1 0 100% /dev | /dev/ada1p4 5061628 535004 4121696 11% /var | /dev/ada1p5 978973296 21689416 878966020 2% /usr | | 14:24 [2] (2) "autofs" root@thompson# mount | /dev/ada1p2 on / (ufs, local) | devfs on /dev (devfs, local, multilabel) | /dev/ada1p4 on /var (ufs, local, soft-updates) | /dev/ada1p5 on /usr (ufs, local, soft-updates) | | 14:25 [2] (3) "autofs" root@thompson# mkdir /tmp/automounted /tmp/manual | | 14:25 [2] (4) "autofs" root@thompson# mount -t nullfs -o ro /usr/src /tmp/manual | | 14:25 [2] (5) "autofs" root@thompson# mount -t nullfs -o ro,automounted /usr/src /tmp/automounted/ | | 14:26 [2] (6) "autofs" root@thompson# df | Filesystem 1K-blocks Used Avail Capacity Mounted on | /dev/ada1p2 5061628 707264 3949436 15% / | devfs 1 1 0 100% /dev | /dev/ada1p4 5061628 535004 4121696 11% /var | /dev/ada1p5 978973296 21689420 878966016 2% /usr | /usr/src 978973296 21689420 878966016 2% /tmp/manual | /usr/src 978973296 21689420 878966016 2% /tmp/automounted | | 14:26 [2] (7) "autofs" root@thompson# mount | /dev/ada1p2 on / (ufs, local) | devfs on /dev (devfs, local, multilabel) | /dev/ada1p4 on /var (ufs, local, soft-updates) | /dev/ada1p5 on /usr (ufs, local, soft-updates) | /usr/src on /tmp/manual (nullfs, local, read-only) | /usr/src on /tmp/automounted (nullfs, local, read-only, automounted) | | 14:26 [2] (8) "autofs" root@thompson# ./a.out | skipping /, not automounted | skipping /dev, not automounted | skipping /var, not automounted | skipping /usr, not automounted | skipping /tmp/manual, not automounted | skipping /tmp/automounted, not automounted | | 14:26 [2] (9) "autofs" root@thompson# ./a.out x | skipping /, not automounted | skipping /dev, not automounted | skipping /var, not automounted | skipping /usr, not automounted | skipping /tmp/manual, not automounted | /tmp/automounted IS automounted!!!!!!!!!