VFS_FRUIT

Section: System Administration tools (8)
Updated: 04/07/2021
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NAME

vfs_fruit - Enhanced OS X and Netatalk interoperability

SYNOPSIS

: vfs objects = fruit

DESCRIPTION

This VFS module is part of the samba(7) suite.

The vfs_fruit module provides enhanced compatibility with Apple SMB clients and interoperability with a Netatalk 3 AFP fileserver.

The module should be stacked with vfs_catia if enabling character conversion and must be stacked with vfs_streams_xattr, see the example section for the correct config.

The module enables alternate data streams (ADS) support for a share, intercepts the OS X special streams "AFP_AfpInfo" and "AFP_Resource" and handles them in a special way. All other named streams are deferred to vfs_streams_xattr which must be loaded together with vfs_fruit.

Be careful when mixing shares with and without vfs_fruit. OS X clients negotiate SMB2 AAPL protocol extensions on the first tcon, so mixing shares with and without fruit will globally disable AAPL if the first tcon is without fruit.

Having shares with ADS support enabled for OS X client is worthwhile because it resembles the behaviour of Apple's own SMB server implementation and it avoids certain severe performance degradations caused by Samba's case sensitivity semantics.

The OS X metadata and resource fork stream can be stored in a way compatible with Netatalk 3 by setting fruit:resource = file and fruit:metadata = netatalk.

OS X maps NTFS illegal characters to the Unicode private range in SMB requests. By setting fruit:encoding = native, all mapped characters are converted to native ASCII characters.

Finally, share access modes are optionally checked against Netatalk AFP sharing modes by setting fruit:locking = netatalk.

This module is not stackable other than described in this manpage.

GLOBAL OPTIONS

The following options must be set in the global smb.conf section and won't take effect when set per share.

fruit:aapl = yes | no

A global option whether to enable Apple's SMB2+ extension codenamed AAPL. Default yes. This extension enhances several deficiencies when connecting from Macs:

: • directory enumeration is enriched with Mac relevant filesystem metadata (UNIX mode, FinderInfo, resource fork size and effective permission), as a result the Mac client doesn't need to fetch this metadata individually per directory entry resulting in an often tremendous performance increase.

: • The ability to query and modify the UNIX mode of directory entries.

There's a set of per share options that come into play when fruit:aapl is enabled. These options, listed below, can be used to disable the computation of specific Mac metadata in the directory enumeration context, all are enabled by default:

: • readdir_attr:aapl_rsize = yes | no

: • readdir_attr:aapl_finder_info = yes | no

: • readdir_attr:aapl_max_access = yes | no

See below for a description of these options.

fruit:nfs_aces = yes | no

: A global option whether support for querying and modifying the UNIX mode of directory entries via NFS ACEs is enabled, default yes.

fruit:copyfile = yes | no

A global option whether to enable OS X specific copychunk ioctl that requests a copy of a whole file along with all attached metadata.

WARNING: the copyfile request is blocking the client while the server does the copy.

The default is no.

fruit:model = MacSamba

: This option defines the model string inside the AAPL extension and will determine the appearance of the icon representing the Samba server in the Finder window.
The default is MacSamba.

OPTIONS

The following options can be set either in the global smb.conf section or per share.

fruit:resource = [ file | xattr | stream ]

Controls where the OS X resource fork is stored.

Due to a spelling bug in all Samba versions older then 4.6.0, this option can also be given as fruit:ressource, ie with two s.

Settings:

: • file (default) - use a ._ AppleDouble file compatible with OS X and Netatalk

: • xattr - use a xattr, requires a filesystem with large xattr support and a file IO API compatible with xattrs, this boils down to Solaris and derived platforms and ZFS

: • stream (experimental) - pass the stream on to the next module in the VFS stack. Warning: this option should not be used with the streams_xattr module due to the extended attributes size limitations of most filesystems.

fruit:time machine = [ yes | no ]

Controls if Time Machine support via the FULLSYNC volume capability is advertised to clients.

: • yes - Enables Time Machine support for this share. Also registers the share with mDNS in case Samba is built with mDNS support.

: • no (default) Disables advertising Time Machine support.

This option enforces the following settings per share (or for all shares if enabled globally):

: • durable handles = yes

: • kernel oplocks = no

: • kernel share modes = no

: • posix locking = no

fruit:time machine max size = SIZE [K|M|G|T|P]

Useful for Time Machine: limits the reported disksize, thus preventing Time Machine from using the whole real disk space for backup. The option takes a number plus an optional unit.

IMPORTANT: This is an approximated calculation that only takes into account the contents of Time Machine sparsebundle images. Therefore you MUST NOT use this volume to store other content when using this option, because it would NOT be accounted.

The calculation works by reading the band size from the Info.plist XML file of the sparsebundle, reading the bands/ directory counting the number of band files, and then multiplying one with the other.

fruit:metadata = [ stream | netatalk ]

Controls where the OS X metadata stream is stored:

: • netatalk (default) - use Netatalk compatible xattr

: • stream - pass the stream on to the next module in the VFS stack

fruit:locking = [ netatalk | none ]

: • none (default) - no cross protocol locking

: • netatalk - use cross protocol locking with Netatalk

fruit:encoding = [ native | private ]

Controls how the set of illegal NTFS ASCII character, commonly used by OS X clients, are stored in the filesystem.

Important: this is known to not fully work with fruit:metadata=stream or fruit:resource=stream.

: • private (default) - store characters as encoded by the OS X client: mapped to the Unicode private range

: • native - store characters with their native ASCII value. Important: this option requires the use of vfs_catia in the VFS module stack as shown in the examples section.

fruit:veto_appledouble = yes | no

Note: this option only applies when fruit:resource is set to file (the default).

When fruit:resource is set to file, vfs_fruit may create ._ AppleDouble files. This options controls whether these ._ AppleDouble files are vetoed which prevents the client from accessing them.

Vetoing ._ files may break some applications, e.g. extracting Mac ZIP archives from Mac clients fails, because they contain ._ files. rsync will also be unable to sync files beginning with underscores, as the temporary files it uses for these will start with ._ and so cannot be created.

Setting this option to false will fix this, but the abstraction leak of exposing the internally created ._ files may have other unknown side effects.

The default is yes.

fruit:posix_rename = yes | no

: Whether to enable POSIX directory rename behaviour for OS X clients. Without this, directories can't be renamed if any client has any file inside it (recursive!) open.
The default is yes.

readdir_attr:aapl_rsize = yes | no

: Return resource fork size in SMB2 FIND responses.
The default is yes.

readdir_attr:aapl_finder_info = yes | no

: Return FinderInfo in SMB2 FIND responses.
The default is yes.

readdir_attr:aapl_max_access = yes | no

: Return the user's effective maximum permissions in SMB2 FIND responses. This is an expensive computation, setting this to off pretends the use has maximum effective permissions.
The default is yes.

fruit:wipe_intentionally_left_blank_rfork = yes | no

: Whether to wipe Resource Fork data that matches the special 286 bytes sized placeholder blob that macOS client create on occasion. The blob contains a string "This resource fork intentionally left blank", the remaining bytes being mostly zero. There being no one use of this data, it is probably safe to discard it. When this option is enabled, this module truncates the Resource Fork stream to 0 bytes.
The default is no.

fruit:delete_empty_adfiles = yes | no

: Whether to delete empty AppleDouble files. Empty means that the resource fork entry in the AppleDouble files is of size 0, or the size is exactly 286 bytes and the content matches a special boilerplate resource fork created my macOS.
The default is no.

fruit:zero_file_id = yes | no

Whether to return zero to queries of on-disk file identifier if the client has negotiated AAPL.

Mac applications and / or the Mac SMB client code expect the on-disk file identifier to have the semantics of HFS+ Catalog Node Identifier (CNID). Samba provides File-IDs based on a file's initial creation date if the option m[blue]store dos attributesm[] is enabled. Returning a file identifier of zero causes the Mac client to stop using and trusting the file id returned from the server.

The default is yes.

EXAMPLES

        [share]
        m[blue]vfs objects = catia fruit streams_xattrm[]
        m[blue]fruit:resource = filem[]
        m[blue]fruit:metadata = netatalkm[]
        m[blue]fruit:locking = netatalkm[]
        m[blue]fruit:encoding = nativem[]

AUTHOR

The original Samba software and related utilities were created by Andrew Tridgell. Samba is now developed by the Samba Team as an Open Source project similar to the way the Linux kernel is developed.