freebsd-dev/sys/cddl
Steven Hartland ca6505b818 Prevent ZFS leaking pool free space
When processing async destroys ZFS would leak space every txg timeout
(5 seconds by default), if no writes occurred, until the pool is totally
full. At this point it would be unfixable without a pool recreation.

In addition if the machine was rebooted with the pool in this situation
would fail to import on boot, hanging indefinitely, as the import process
requires the ability to write data to the pool. Any attempts to query the
pool status during the hung import would not return as the import holds
the pool lock.

The only way to import such a pool would be to specify -o readonly=on
to the zpool import.

zdb -bb <pool> can be used to check for "deferred free" size which is where
this lost space will be counted.

MFC after:	3 days
Sponsored by:	Multiplay
2014-10-16 02:23:27 +00:00
..
boot/zfs Diff reduction with kernel code: instruct the compiler that the data of 2014-10-02 00:13:08 +00:00
compat/opensolaris make userland __assfail from opensolaris compat honor 'aok' variable 2014-10-07 14:15:50 +00:00
contrib/opensolaris Prevent ZFS leaking pool free space 2014-10-16 02:23:27 +00:00
dev Fix the stack tracing for dtrace/powerpc. 2014-09-17 02:43:47 +00:00