K 10
svn:author
V 7
asomers
K 8
svn:date
V 27
2013-10-14T23:31:18.240128Z
K 7
svn:log
V 2617
Improve zfsd's spare handling.

	Zfsd can now:
	- Spare broken spares, whether a case file is created for the
	  original drive or for the previous spare.
	- Avoid sparing spares that are either resilvering or healthy.  This
	  enables failover of multiple devices in a pool.  It also means
	  that zfsd doesn't require more spares than are actually needed to
	  make a pool whole again.

	cddl/sbin/zfsd/vdev.h:
	cddl/sbin/zfsd/vdev.cc:
	- Add NonexistentVdev, a singleton instance of Vdev that represents
	  a vdev that doesn't exist.  Supporting this are new methods:
	  - Vdev::Vdev(), an empty copy constructor.
	  - Vdev::DoesNotExist(), which returns true if the vdev doesn't
	    exist.
	- Add vdev tree methods of use for purposes for which VdevIterator
	  is not appropriate:
	  - Vdev::Children(), which returns a list of the vdev's children.
	  - Vdev::RootVdev(), which returns the root vdev of the vdev's pool.
	  - Vdev::Parent(), which returns the vdev's parent.  This works by
	    traversing the tree until it finds a vdev whose children include
	    the caller object.
	- Add several useful vdev instance methods:
	  - Vdev::IsAvailableSpare(), which returns whether the vdev is an
	    unassigned and usable spare.
	  - Vdev::Name(), which returns the vdev's name; it can be made to
	    return a "verbose" name too (e.g. "spare" vs. "spare-1").
	  - Vdev::IsSpare(), Vdev::IsActiveSpare(), and Vdev::IsResilvering().
	- While I'm here, refactor Vdev::Vdev(*) so that common
	  initialization code only exists in one place.

	cddl/sbin/zfsd/case_file.h:
	cddl/sbin/zfsd/case_file.cc:
	- Add CaseFile::BeingReplacedBy(), which returns the device
	  replacing the current device, if one exists.  Performing this
	  requires finding the vdev's parent and checking the state of its
	  children.
	- Change CaseFile::Replace() to allow the caller to specify whether
	  the case's vdev is being replaced by a spare.  This enables
	  Replace() to detect the appropriate device to perform the actual
	  replace on.
	- Add CaseFile::CaseVdev() to obtain a Vdev for the case file, and
	  use it in several places that perform the operation.

	cddl/sbin/zfsd/case_file.cc:
	- Improve logging for case file evaluation so that the action chosen
	  is always logged.
	- While I'm here, make zpool lookups consistent and always generate
	  a zpool_handle_t * local to the function where it's needed.

	cddl/sbin/zfsd/vdev.h:
	cddl/sbin/zfsd/zfsd_exception.cc:
	- Add <list>, now required because of Vdev::Children() in vdev.h.

Submitted by:	will
Approved by:	ken (mentor)
Sponsored by:	Spectra Logic Corporation

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