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Description of problem:
I've setup two different exports on the same server and mount the two exports from the same client.
So on server I have /mnt/nfsexport and /mnt/nfsscratch exported
/mnt/nfsexport *(rw,no_root_squash)
/mnt/nfsscratch *(rw,no_root_squash)
On client, mount the two exports with the same mount option(all default)
mount -t nfs server:/mnt/nfsexport /mnt/test
mount -t nfs server:/mnt/nfsscratch /mnt/scratch
Now I remount nfsscratch to readonly, the first mount will be readonly too
mount -t nfs -o remount,ro server:/mnt/nfsscratch /mnt/scratch
touch /mnt/test/testfile <======== touch fails here because of EROFS
Version-Release number of selected component (if applicable):
kernel-3.10.0-193.el7
upstream 3.18-rc2 kernel
How reproducible:
always
Steps to Reproduce:
# mount two different exports on the same server
[root@ibm-x3650m4-08 nfs-remount]# mount -t nfs hp-dl388eg8-01.rhts.eng.nay.redhat.com:/mnt/nfsexport /mnt/test
[root@ibm-x3650m4-08 nfs-remount]# mount -t nfs hp-dl388eg8-01.rhts.eng.nay.redhat.com:/mnt/nfsscratch /mnt/scratch
# The two mounts are all rw
[root@ibm-x3650m4-08 nfs-remount]# grep dl388 /proc/mounts
hp-dl388eg8-01.rhts.eng.nay.redhat.com:/mnt/nfsexport /mnt/test nfs4 rw,relatime,vers=4.0,rsize=1048576,wsize=1048576,namlen=255,hard,proto=tcp,port=0,timeo=600,retrans=2,sec=sys,clientaddr=10.66.86.161,local_lock=none,addr=10.66.86.132 0 0
hp-dl388eg8-01.rhts.eng.nay.redhat.com:/mnt/nfsscratch /mnt/scratch nfs4 rw,relatime,vers=4.0,rsize=1048576,wsize=1048576,namlen=255,hard,proto=tcp,port=0,timeo=600,retrans=2,sec=sys,clientaddr=10.66.86.161,local_lock=none,addr=10.66.86.132 0 0
# remount the second ro
[root@ibm-x3650m4-08 nfs-remount]# mount -t nfs -o remount,ro hp-dl388eg8-01.rhts.eng.nay.redhat.com:/mnt/nfsscratch /mnt/scratch
# check mount options again, the first mount is ro too
[root@ibm-x3650m4-08 nfs-remount]# grep dl388 /proc/mounts
hp-dl388eg8-01.rhts.eng.nay.redhat.com:/mnt/nfsexport /mnt/test nfs4 ro,relatime,vers=4.0,rsize=1048576,wsize=1048576,namlen=255,hard,proto=tcp,port=0,timeo=600,retrans=2,sec=sys,clientaddr=10.66.86.161,local_lock=none,addr=10.66.86.132 0 0
hp-dl388eg8-01.rhts.eng.nay.redhat.com:/mnt/nfsscratch /mnt/scratch nfs4 ro,relatime,vers=4.0,rsize=1048576,wsize=1048576,namlen=255,hard,proto=tcp,port=0,timeo=600,retrans=2,sec=sys,clientaddr=10.66.86.161,local_lock=none,addr=10.66.86.132 0 0
# touch will fail
[root@ibm-x3650m4-08 nfs-remount]# touch /mnt/test/testfile
touch: cannot touch ‘/mnt/test/testfile’: Read-only file system
Actual results:
the first mount becomes ro too
Expected results:
the first mount is still rw
Additional info:
mount with nosharecache option will fix this issue.
Not sure if it's really a bug, but I don't this should be the right behavior.
Yes, I know the nosharecache mount option could workaround this issue (as stated in the "Additional info" section in comment 0).
I'm just not sure if it's a bug in the not mounting with nosharecache option situation. From the nfs(5) I can see the description for sharecache/nosharecache
"Determines how the client's data cache and attribute cache are shared when mounting the same export more than once concurrently."
So I think nosharecache option should only make difference when the exports are identical. But in this bug we're mounting two different exports.
(In reply to Eryu Guan from comment #3)
> So I think nosharecache option should only make difference when the exports
> are identical. But in this bug we're mounting two different exports.
If the two different exports are from the same server and share the same fsid (so they're really part of the same filesystem on the server) then I'd expect the client to treat them as the same export.
(In reply to J. Bruce Fields from comment #4)
> If the two different exports are from the same server and share the same
> fsid (so they're really part of the same filesystem on the server) then I'd
> expect the client to treat them as the same export.
Yes, you're right, I missed that. Tested by exporting different filesystems on server and remount ro just worked fine, only one mountpoint became readonly.
Thanks for the explanation. Closed as NOTABUG.