Bug 1353680
| Summary: | NFSv4 export of "/" doesn't respect "crossmnt" export option | ||||||
|---|---|---|---|---|---|---|---|
| Product: | Red Hat Enterprise Linux 7 | Reporter: | Steve Dickson <steved> | ||||
| Component: | nfs-utils | Assignee: | Steve Dickson <steved> | ||||
| Status: | CLOSED ERRATA | QA Contact: | Yongcheng Yang <yoyang> | ||||
| Severity: | medium | Docs Contact: | |||||
| Priority: | unspecified | ||||||
| Version: | 7.3 | CC: | bfields, dwysocha, eguan, raarora, steved, yoyang | ||||
| Target Milestone: | rc | Keywords: | Patch, Reproducer | ||||
| Target Release: | --- | ||||||
| Hardware: | Unspecified | ||||||
| OS: | Linux | ||||||
| Whiteboard: | |||||||
| Fixed In Version: | nfs-utils-1.3.0-0.31.el7 | Doc Type: | If docs needed, set a value | ||||
| Doc Text: | Story Points: | --- | |||||
| Clone Of: | 1331207 | Environment: | |||||
| Last Closed: | 2016-11-04 05:04:16 UTC | Type: | Bug | ||||
| Regression: | --- | Mount Type: | --- | ||||
| Documentation: | --- | CRM: | |||||
| Verified Versions: | Category: | --- | |||||
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |||||
| Cloudforms Team: | --- | Target Upstream Version: | |||||
| Embargoed: | |||||||
| Bug Depends On: | 1331207 | ||||||
| Bug Blocks: | |||||||
| Attachments: |
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Created attachment 1177399 [details]
The back ported patches
Also have checked the man page update.
[root@ibm-x3250m4-07 ~]# rpm -q nfs-utils
nfs-utils-1.3.0-0.31.el7.x86_64
[root@ibm-x3250m4-07 ~]# man exports | col -b | sed -n '/nohide/,/no_subtree_check/p'
nohide This option is based on the option of the same name provided in IRIX NFS. Normally, if a server exports two filesystems one of
which is mounted on the other, then the client will have to mount both filesystems explicitly to get access to them. If it just
mounts the parent, it will see an empty directory at the place where the other filesystem is mounted. That filesystem is "hid‐
den".
Setting the nohide option on a filesystem causes it not to be hidden, and an appropriately authorised client will be able to move
from the parent to that filesystem without noticing the change.
However, some NFS clients do not cope well with this situation as, for instance, it is then possible for two files in the one
apparent filesystem to have the same inode number.
The nohide option is currently only effective on single host exports. It does not work reliably with netgroup, subnet, or wild‐
card exports.
This option can be very useful in some situations, but it should be used with due care, and only after confirming that the client
system copes with the situation effectively.
The option can be explicitly disabled for NFSv2 and NFSv3 with hide.
This option is not relevant when NFSv4 is use. NFSv4 never hides subordinate filesystems. Any filesystem that is exported will
be visible where expected when using NFSv4.
crossmnt
This option is similar to nohide but it makes it possible for clients to access all filesystems mounted on a filesystem marked
with crossmnt. Thus when a child filesystem "B" is mounted on a parent "A", setting crossmnt on "A" has a similar effect to set‐
ting "nohide" on B.
With nohide the child filesystem needs to be explicitly exported. With crossmnt it need not. If a child of a crossmnt file is
not explicitly exported, then it will be implicitly exported with the same export options as the parent, except for fsid=. This
makes it impossible to not export a child of a crossmnt filesystem. If some but not all subordinate filesystems of a parent are
to be exported, then they must be explicitly exported and the parent should not have crossmnt set.
The nocrossmnt option can explictly disable crossmnt if it was previously set. This is rarely useful.
no_subtree_check
[root@ibm-x3250m4-07 ~]#
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory, and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://rhn.redhat.com/errata/RHBA-2016-2383.html |
These are the needed commits commit 0f1f4e7278c1bc93d54da1026dfe484f27bcd873 Author: NeilBrown <neilb> Date: Thu Feb 26 14:10:35 2015 -0500 exports.man: improve documentation of 'nohide' and 'crossmnt' commit 1e4a4c3816ca5a1e1a345117a201d9cc6c468beb Author: NeilBrown <neilb> Date: Wed Feb 25 16:47:56 2015 -0500 mountd: fix next_mnt handling for "/" commit 78240c41be17bd20d5fb5b70b6f470d8e779adee Author: Vivek Trivedi <t.vivek> Date: Wed Sep 16 11:14:03 2015 -0400 mountd: fix mount issue due to comparison with uninitialized uuid