On Sun, Nov 07, 2021 at 04:50:21PM -0600, Steve French wrote:
That is interesting ... and weird. Why would POSIX allow doing
something write related (fsync) without write permission?
It's not POSIX, it's Linux :-).
It also operates on meta-data, so if the buffer cache
has any pending changes on a read-only fd, then fsync(fd)
will flush them.
man 2 fsync.
..
As well as flushing the file data, fsync() also flushes the metadata
information associated with the file (see inode(7)).
I think cifsfs needs to keep track of the file modes
and silently return success on a read-only fd even
if mounted without nostrictsync.
