K 10
svn:author
V 7
asomers
K 8
svn:date
V 27
2013-10-14T21:50:56.931478Z
K 7
svn:log
V 885
Fix a bug in zfsd: when a drive is experiencing a rapid storm of IO or
checksum errors, zfsd will not degrade/fault it until hundreds or thousands
of errors have occured.

	cddl/sbin/zfsd/case_file.cc
		RefreshVdevState() iterates through all the system's zpools,
		which involves the ioctls ZFS_IOC_POOL_CONFIGS and
		ZFS_IOC_POOL_STATS.  Both of those acquire
		spa_namespace_lock, which may block for a long time under
		certain circumstances, including when the system has a storm
		of IO or checksum errors.  This change eliminates the call
		to RefreshVdevState() whenever a ZFSEvent is received.
		Instead, RefreshVdevState() will only be called when a
		CaseFile is closed, if necessary.  This way, zfsd won't
		spend too much time blocking on ioctl()s and miss reading
		events from devd.

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

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