OpenZFS on Linux and FreeBSD
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Richard Yao 7809eb8b65 ztest: Switch to LWP rwlock interface
ztest is intended to subject the ZFS code in userland to stress that it
should be able to withstand. Any failures that occur when running it are
failures that likely would occur inside the kernel. However, being in
userland, it is much easier to debug them. In practice, this prevents
a large number of problems from reaching production code.

A design decision was made by the original authors of ztest to make a
distinction between userland locking primitives and kernel locking
primitives. The ztest code itself calls userland locking primitives
while the kernel code being run in userland will call emulated kernel
locking primitives that wrap the userland locking primitives.

When ztest was first ported to Linux, a decision was made to use the
emulated kernel interfaces everywhere. In effect, the userland
rw_rdlock()/rw_wrlock() became the kernel rw_enter() and and the userland
rw_unlock() became the kernel rw_exit(). This caused a regression
because of an assertion in rw_enter() to catch recursive locking. That
is permitted in userland, but not in the kernel. Consequently, the ztest
code itself does recursive read locking. The use of the emulated kernel
interfaces consequently caused the following failure:

ztest: ../../lib/libzpool/kernel.c:384: Assertion `rwlp->rw_owner !=
zk_thread_current() (0x1c87150 != 0x1c87150)' failed.

That occurs because ztest_dmu_objset_create_destroy() will take a read
lock and call ztest_dmu_object_alloc_free(). That will call ztest_io(),
which will take a readlock only when asked to do ZTEST_IO_REWRITE. This
triggered the assertion.

The pthreads rwlock interface was based on the LWP rwlock interface
implemented in Illumos libc. Luckily enough, the subset used by ztest is
almost identical, so we can solve this problem by switching to the LWP
thread rwlock interface in ztest. This eliminates a point of divergence
with Illumos and should make code sharing slightly easier.

Signed-off-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #1970
2014-05-01 15:53:58 -07:00
cmd ztest: Switch to LWP rwlock interface 2014-05-01 15:53:58 -07:00
config Refactor inode_owner_or_capable() autotools check 2014-05-01 10:06:49 -07:00
dracut Refresh dracut module setup 2013-03-21 12:51:06 -07:00
etc Allow specifying '-o <opts>' in defaults/init script. 2014-04-04 09:49:09 -07:00
include libspl: Implement LWP rwlock interface 2014-05-01 15:53:52 -07:00
lib libspl: Implement LWP rwlock interface 2014-05-01 15:53:52 -07:00
man Initial implementation of zed (ZFS Event Daemon) 2014-04-02 13:10:03 -07:00
module dmu_tx_assign() should not return ENOMEM 2014-05-01 12:08:53 -07:00
patches Adding grub2 mkconfig support patch 2012-07-30 16:17:23 -07:00
rpm Initial implementation of zed (ZFS Event Daemon) 2014-04-02 13:10:03 -07:00
scripts Various zimport.sh fixes 2014-04-17 09:30:55 -07:00
udev Open pools asynchronously after module load 2013-07-03 09:24:38 -07:00
.gitignore Ignore *.{deb,rpm,tar.gz} files in the top directory. 2013-04-24 16:18:59 -07:00
.gitmodules Add zimport.sh compatibility test script 2014-02-21 12:10:31 -08:00
AUTHORS Fix minor typos and update marketing copy. 2013-03-21 12:51:06 -07:00
COPYRIGHT Refresh links to web site 2013-03-06 15:46:41 -08:00
DISCLAIMER Fix minor typos and update marketing copy. 2013-03-21 12:51:06 -07:00
META Tag zfs-0.6.2 2013-08-22 13:33:26 -07:00
Makefile.am cstyle: Exclude several files from 'make checkstyle' 2013-12-18 16:46:35 -08:00
OPENSOLARIS.LICENSE Add CDDL license file 2008-12-01 14:49:34 -08:00
README.markdown Fix minor typos and update marketing copy. 2013-03-21 12:51:06 -07:00
autogen.sh build: do not call boilerplate ourself 2013-04-02 10:55:20 -07:00
configure.ac Initial implementation of zed (ZFS Event Daemon) 2014-04-02 13:10:03 -07:00
copy-builtin Consistent menuconfig name 2012-08-26 13:49:37 -07:00
zfs-script-config.sh.in Initial implementation of zed (ZFS Event Daemon) 2014-04-02 13:10:03 -07:00
zfs.release.in Move zfs.release generation to configure step 2012-07-12 12:22:51 -07:00

README.markdown

Native ZFS for Linux!

ZFS is an advanced file system and volume manager which was originally developed for Solaris and is now maintained by the Illumos community.

ZFS on Linux, which is also known as ZoL, is currently feature complete. It includes fully functional and stable SPA, DMU, ZVOL, and ZPL layers.

Full documentation for installing ZoL on your favorite Linux distribution can be found at: http://zfsonlinux.org