[PATCH 11/11][v3]: Enable multiple instances of devpts

sukadev at us.ibm.com sukadev at us.ibm.com
Sat Sep 6 14:45:56 PDT 2008

H. Peter Anvin [hpa at zytor.com] wrote:
> sukadev at us.ibm.com wrote:
>> Agree in general. Not sure if you are implying remount is necessary just
>> to change permissions of pts/ptmx. Why not "chmod 0666 /dev/pts/ptmx" ?
>> The remount changes the 'ptmxmode' setting, but since the node exists,
>> the 'ptmxmode' setting is never used again and we need to chmod.
> A chmod requires bigger changes to existing scripts than an option which 
> can be set in /etc/fstab.

Ok. From implementation pov, we can cache the ptmx dentry in s_fs_info
and use it during remount to change the permissions. We could lookup
ptmx during remount, but caching is simpler ?

>> ptmx node in multi-instance mounts continue to get PTMX_DEFAULT_MODE
>> permissions (not 000) right ? (unless -o ptmxmode is specified)
> It's probably easier to always default it to zero and expect that the mode 
> is set explicitly.


BTW, I have added CONFIG_DEVPTS_MULTIPLE_INSTANCES and moved the usage
info from 11/11 to Documentation/fs/devpts.txt.

Will make above ptmx changes, port to recent ttydev tree and send updated
patchset in a couple of days.



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