tree 8e38db1be28006894915273b3f3cb3beaa6efda3
parent 2fb1e3086df9b454538491fba8121298da37cd23
author Linus Torvalds <torvalds@g5.osdl.org> 1124499776 -0700
committer Linus Torvalds <torvalds@g5.osdl.org> 1124499776 -0700

Fix nasty ncpfs symlink handling bug.

This bug could cause oopses and page state corruption, because ncpfs
used the generic page-cache symlink handlign functions.  But those
functions only work if the page cache is guaranteed to be "stable", ie a
page that was installed when the symlink walk was started has to still
be installed in the page cache at the end of the walk.

We could have fixed ncpfs to not use the generic helper routines, but it
is in many ways much cleaner to instead improve on the symlink walking
helper routines so that they don't require that absolute stability.

We do this by allowing "follow_link()" to return a error-pointer as a
cookie, which is fed back to the cleanup "put_link()" routine.  This
also simplifies NFS symlink handling.

Signed-off-by: Linus Torvalds <torvalds@osdl.org>