Pull overlayfs updates from Miklos Szeredi:
"This work from Amir adds NFS export capability to overlayfs. NFS
exporting an overlay filesystem is a challange because we want to keep
track of any copy-up of a file or directory between encoding the file
handle and decoding it.
This is achieved by indexing copied up objects by lower layer file
handle. The index is already used for hard links, this patchset
extends the use to NFS file handle decoding"
* 'overlayfs-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs: (51 commits)
ovl: check ERR_PTR() return value from ovl_encode_fh()
ovl: fix regression in fsnotify of overlay merge dir
ovl: wire up NFS export operations
ovl: lookup indexed ancestor of lower dir
ovl: lookup connected ancestor of dir in inode cache
ovl: hash non-indexed dir by upper inode for NFS export
ovl: decode pure lower dir file handles
ovl: decode indexed dir file handles
ovl: decode lower file handles of unlinked but open files
ovl: decode indexed non-dir file handles
ovl: decode lower non-dir file handles
ovl: encode lower file handles
ovl: copy up before encoding non-connectable dir file handle
ovl: encode non-indexed upper file handles
ovl: decode connected upper dir file handles
ovl: decode pure upper file handles
ovl: encode pure upper file handles
ovl: document NFS export
vfs: factor out helpers d_instantiate_anon() and d_alloc_anon()
ovl: store 'has_upper' and 'opaque' as bit flags
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