iSCSI Integration (shareiscsi)

[behlendorf]

This is iSCSI sharing for ZoL (shareiscsi).

• Supports the following iSCSI implementations (in this order of discovery):
  • IET http://iscsitarget.sourceforge.net
  • STGT http://stgt.berlios.de
  • SCST http://scst.sourceforge.net
    • Requires that SCST was compiled with /sys support (the default).
  • LIO http://linux-iscsi.org
• Will refuse to unshares an active target (one with sessions).
• Supports the following options to the 'shareiscsi' property:
  • name/iqn Full iSCSI Qualified Name (IQN), including identifier.
    This is generated by iscsi_generate_target():
    + Uses the content of an optional /etc/iscsi_target_id file:
    Example: iqn.YYYY-MM.tld.domain
    + If this file doesn't exist, it uses the current year, month
    and domain name to generate the iqn.
    + The dataset name is appended at the end of the iqn, with
    slashes replaced with dots.
    => :
  • lun LUN (0-16384)
    Default: 0 (1 for STGT)
  • type Share mode (fileio, blockio, nullio, disk, tape)
    STGT: ssc, pt
    Default: blockio (disk for STGT)
  • iomode IO mode (wb, wt, ro)
    STGT: rdwr, aio, mmap, sg, ssc
    Default: wt (rdwr for STGT)
  • blocksize Logical block size (512, 1024, 2048, 4096)
    Default: Volume blocksize, 4096 if not usable.
    NOTE: Currently not supported for STGT (doesn't seem to be
    an option for it in tgtadm).
  • initiator Allow only this initiator to bind to target.
    Currently only availible for LIO, STGT and SCST.
  • authname Global user to use in binds on targets.
  • authpass Password for global user.
• If not called with a 'name/iqn' value, then force setting it.
  This so that the IQN doesn't change every month (when it is
  regenerated again). It will be generated by iscsi_generate_target()
  (see above).

NOTE:

• Moved nfs.c:foreach_nfs_shareopt() to libshare.c:foreach_shareopt()
  so that it can be (re)used in smb.c and iscsi.c.

• Split iSCSI implementation into their own separate source files

• Use the list_{create,insert}() etc for keeping tabs of the linked lists
  instead of using a home-made version.

• A half second delay had to be added in lib/libzfs/libzfs_mount.c:zfs_unmount()
  after the successful unshare. This to avoid 'dataset busy' when destroying
  recursivly.
  = The 'initiator', 'authname' and 'authpass' option might have some issues:
  It will make the compatibility between the different iSCSI implementations
  questionable - can't switch between them easily (it will ONLY be availible
  in ZoL). I COULD make the option be silently ignored (instead of forcibly
  rejected if not availible).

  But that still doesn't solve the (possible) problem between ZoL and
  OpenZFS/Illumos (setting the option, will possibly introduce problems when
  importing the pool on something else than ZoL).

  So some more discussion might be needed..

[behlendorf]

Closing see original #1099 pull request for review and comment.

[sempervictus]

Thanks, will work off this PR moving forward.

[behlendorf]

Closing. The patches will remain available for those who want to apply them.