Adjust all struct dirent creations (again), this time to use offsetof().

The dirent struct is not packed, so offsetof(dirent, d_name) != sizeof(dirent).
Thus in order not to waste the alignment bytes (which are significant,
on x86_64 at least, sizeof(dirent)==32, but offsetof(...)=26.)

This is also the most portable way to handle things, and should
work just fine in cross-platform code that has a non-zero-sized d_name.

nfs4: Fix CID #991617: Set cookie file system at its creation

nfs4: use exponential backoff when the server ask to wait

nfs4: Fix CID 990984 and 991173: missing assignment in error check

nfs4: DirectoryCache::GetSnapshot may return NULL

nfs4: Remove CacheRevalidator

There is no point in periodically revalidating all existing directory caches.
Directory snapshot can be revalidated when readdir is invoked.

nfs4: Fix problems with reading directory entries
* Inode::ReadDir missed an entry when given buffer was too small
* Each OpenDirCookie now has its own copy of directory snapshot what
would prevent Inode::ReadDir from accessing freed memory when removing
files and reading directory entries simultaneously
* Several minor issues fixed

nfs4: Introduce VnodeToInode mapping

VnodeToInode is another abstraction layer between VFS vnodes and NFS nodes.
It simplifies dealing with race conditions as well as faking some guarantees
VFS expects but NFS does not provide.

nfs4: Add numerous assertion checks

nfs4, dns_resolver: fix numerous style violations

nfs4: Fix some cache revalidator problems

nfs4: Fix several problems with emulated attributes

nfs4: Make the client more configurable

nfs4: Add basic emulation of named attributes

nfs4: Do not repeat OPENATTR requests if not supported

nfs4: Add basic support for extended attributes

nfs4: Inode::GetDirSnapshot should not require OpenDirCookie

nfs4: Fix mounting server's root directory

nfs4: Add attribute directory related hooks

nfs4: Move low level NFS4 code to Inode's base class

nfs4: Fix several issues introduced in previous commits

nfs4: Local creation of node should not invalidate the cache

nfs4: ReadDir sholud not including '..' and '.'

nfs4: Add full directory cache implementation

nfs4: Do not let local changes invalidate cache

nfs4: Cache file attributes and filesystem info

nfs4: Rename Filehandle to FileHandle and Filesystem to FileSystem

nfs4: Abandon owner and owner_group when id mapping causes problems

nfs4: Do not attempt to set owner, owner_group when not supported

nfs4: Add id mapper

nfs4: Use FileInfo instead of filehandle to identify a file

nfs4: Put file and dir specific code in separate files

nfs4: Fix CID #991617: Set cookie file system at its creation

nfs4: use exponential backoff when the server ask to wait

nfs4: Fix CID 990984 and 991173: missing assignment in error check

nfs4: DirectoryCache::GetSnapshot may return NULL

nfs4: Remove CacheRevalidator

There is no point in periodically revalidating all existing directory caches.
Directory snapshot can be revalidated when readdir is invoked.

nfs4: Fix problems with reading directory entries
* Inode::ReadDir missed an entry when given buffer was too small
* Each OpenDirCookie now has its own copy of directory snapshot what
would prevent Inode::ReadDir from accessing freed memory when removing
files and reading directory entries simultaneously
* Several minor issues fixed

nfs4: Introduce VnodeToInode mapping

VnodeToInode is another abstraction layer between VFS vnodes and NFS nodes.
It simplifies dealing with race conditions as well as faking some guarantees
VFS expects but NFS does not provide.

nfs4: Add numerous assertion checks

nfs4, dns_resolver: fix numerous style violations

nfs4: Fix some cache revalidator problems

nfs4: Fix several problems with emulated attributes

nfs4: Make the client more configurable

nfs4: Add basic emulation of named attributes

nfs4: Do not repeat OPENATTR requests if not supported

nfs4: Add basic support for extended attributes

nfs4: Inode::GetDirSnapshot should not require OpenDirCookie

nfs4: Fix mounting server's root directory

nfs4: Add attribute directory related hooks

nfs4: Move low level NFS4 code to Inode's base class

nfs4: Fix several issues introduced in previous commits

nfs4: Local creation of node should not invalidate the cache

nfs4: ReadDir sholud not including '..' and '.'

nfs4: Add full directory cache implementation

nfs4: Do not let local changes invalidate cache

nfs4: Cache file attributes and filesystem info

nfs4: Rename Filehandle to FileHandle and Filesystem to FileSystem

nfs4: Abandon owner and owner_group when id mapping causes problems

nfs4: Do not attempt to set owner, owner_group when not supported

nfs4: Add id mapper

nfs4: Use FileInfo instead of filehandle to identify a file

nfs4: Put file and dir specific code in separate files