From: Brian Behlendorf <behlendorf1@llnl.gov>
Date: Fri, 26 Oct 2012 17:01:49 +0000 (-0700)
Subject: Add ddt_object_count() error handling
X-Git-Url: https://git.camperquake.de/gitweb.cgi?a=commitdiff_plain;ds=sidebyside;h=e8fd45a0f975c6b8ae8cd644714fc21f14fac2bf;hp=e8fd45a0f975c6b8ae8cd644714fc21f14fac2bf;p=zfs.git

Add ddt_object_count() error handling

The interface for the ddt_zap_count() function assumes it can
never fail.  However, internally ddt_zap_count() is implemented
with zap_count() which can potentially fail.  Now because there
was no way to return the error to the caller a VERIFY was used
to ensure this case never happens.

Unfortunately, it has been observed that pools can be damaged in
such a way that zap_count() fails.  The result is that the pool can
not be imported without hitting the VERIFY and crashing the system.

This patch reworks ddt_object_count() so the error can be safely
caught and returned to the caller.  This allows a pool which has
be damaged in this way to be safely rewound for import.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #910
---