sure preemption is disabled in start_dir_add()/ end_dir_add() sections (on
non-RT it's automatic, on RT it needs to to be done explicitly) and moving
wakeups from __d_lookup_done() inside of such to the end of those sections.
Wakeups can be safely delayed for as long as ->d_lock on in-lookup
dentry is held; proving that has caught a bug in d_add_ci() that allows
memory corruption when sufficiently bogus ntfs (or case-insensitive xfs)
image is mounted. Easily fixed, fortunately.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Merge tag 'pull-work.dcache' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull vfs dcache updates from Al Viro:
"The main part here is making parallel lookups safe for RT - making
sure preemption is disabled in start_dir_add()/ end_dir_add() sections
(on non-RT it's automatic, on RT it needs to to be done explicitly)
and moving wakeups from __d_lookup_done() inside of such to the end of
those sections.
Wakeups can be safely delayed for as long as ->d_lock on in-lookup
dentry is held; proving that has caught a bug in d_add_ci() that
allows memory corruption when sufficiently bogus ntfs (or
case-insensitive xfs) image is mounted. Easily fixed, fortunately"
* tag 'pull-work.dcache' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
fs/dcache: Move wakeup out of i_seq_dir write held region.
fs/dcache: Move the wakeup from __d_lookup_done() to the caller.
fs/dcache: Disable preemption on i_dir_seq write side on PREEMPT_RT
d_add_ci(): make sure we don't miss d_lookup_done()
200e340f21