aio: checking for NULL instead of IS_ERR

alloc_anon_inode() returns an ERR_PTR(), it doesn't return NULL.

Fixes: 71ad7490c1f3 ('rework aio migrate pages to use aio fs')
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
locks: missing unlock on error in generic_add_lease()

We should unlock here before returning.

Fixes: df4e8d2c1d2b ('locks: implement delegations')
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
fix unpaired rcu lock in prepend_path()

Signed-off-by: Li Zhong <zhong@linux.vnet.ibm.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
prepend_path() needs to reinitialize dentry/vfsmount/mnt on restarts

... and equivalent is needed in 3.12; it's broken there as well

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
qib_fs: fix (some) dcache abuses

* lookup_one_len() really wants i_mutex held on directory.
* leaks galore - just mount ipathfs, then
cd /sys/bus/pci/drivers/qib_ib; echo *:*:*.* >unbind
on a box with that card present and try to umount ipathfs...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull VFS fixes from Al Viro:
 "Several fixes, mostly for regressions in the last pile.  Howeover,
  prepend_path() forgetting to reininitalize dentry/vfsmount is in 3.12
  as well and qib_fs had been leaking all along..."

The unpaired RCU lock issue was also independently reported by Dave
Jones with his fuzzer tool..

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  qib_fs: fix (some) dcache abuses
  prepend_path() needs to reinitialize dentry/vfsmount/mnt on restarts
  fix unpaired rcu lock in prepend_path()
  locks: missing unlock on error in generic_add_lease()
  aio: checking for NULL instead of IS_ERR