Re: Symlinks on read-only FS

Is the inclusion of VLNK here correct? I would think that
only the target of the symlink should matter: if it happens
to point onto a writable FS, the fact that the symlink itself
is on a ROFS should not matter.

yes, it is correct.
short symbolic links are stored in the inode itself, so if you
modify a short link, you'll be modifying metadata, which is
not allowed. it could be argued, that as long as the change is
restricted to one inode, it could be tolerable, but moreover,
if your short symbolic link is modified to be longer than fits
in inode, a disk block will need to be allocated, which would
involve a change to block map, which is certainly not desirable
for read-only mounts.

So the sort of write access being validated here would be writing to
the symlink itself (i.e. the definition)? I did not know that could
be done. I had expected that the caller would eventually dereference
the link, and write to its target.

Certainly we wouldn't want to allow changing what the link itself
contains if it is on a ROFS -- indeed this might not even be possible
(e.g. if the FS is recorded on a CDROM).
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