NFS/pnfs: Bulk destroy of layouts needs to be safe w.r.t. umount

[ Upstream commit 5085607d209102b37b169bc94d0aa39566a9842a ]

If a bulk layout recall or a metadata server reboot coincides with a
umount, then holding a reference to an inode is unsafe unless we
also hold a reference to the super block.

Fixes: fd9a8d7160937 ("NFSv4.1: Fix bulk recall and destroy of layouts")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2 files changed