tree d4a8c5d7da4624c4a8973a4c9369af7a915dca05
parent 9b4a9b14a793bc69b505ed916051f6f32db13bb8
author Al Viro <viro@zeniv.linux.org.uk> 1239119393 -0400
committer Al Viro <viro@zeniv.linux.org.uk> 1244770559 -0400

Cache root in nameidata

New field: nd->root.  When pathname resolution wants to know the root,
check if nd->root.mnt is non-NULL; use nd->root if it is, otherwise
copy current->fs->root there.  After path_walk() is finished, we check
if we'd got a cached value in nd->root and drop it.  Before calling
path_walk() we should either set nd->root.mnt to NULL *or* copy (and
pin down) some path to nd->root.  In the latter case we won't be
looking at current->fs->root at all.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>