On Thu, Oct 01, 2009 at 10:55:48AM -0400, Valerie Aurora wrote: > We need to guarantee that a file system will be read-only for as long > as it is the bottom layer of a writable overlay. To do this, we track > the number of "read-only users" of a file system in its VFS superblock > structure. When we mount a writable overlay over a file system, we > increment its read-only user count. The file system can only be > mounted read-write if its read-only users count is zero. > > Todo: > > - Support really really read-only NFS mounts. See discussion here: > > http://markmail.org/message/3mkgnvo4pswxd7lp Is there any way for a file system driver to just come out and say "I can't guarantee that this mount is really read-only"? I can imagine this might be an issue for things other than NFS. I think it would be worthwhile to have a flag maybe on a per sb level that says that even if it is mounted with the "ro" option that it might not really be stable. I don't think this is essential, but it would be a good feature as long as it doesn't damage the design or performance too much. Brad Boyer flar@xxxxxxxxxxxxx -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
