During module load we could deadlock because the zvol_init()
callpath took the spa_namespace_lock before the zvol_state_lock.
The rest of the zvol code takes the locks in the opposite order.
In particular, I observed the following deadlock cause by the
lock inversion.
I've fixed the ording by creating an unlocked version of
zvol_create_minor and zvol_remove_minor. This allows me to
take the zvol_state_lock before the spa_namespace_lock in
zvol_cr_minors_common and simply call the unlocked version.
With the update to onnv_141 how minor devices were created and
removed for ZVOL was substantially changed. The updated system
is much more tightly integrated with Solaris's /dev/ filesystem.
This is great for Solaris but bad for Linux.
On the kernel side the ZFS_IOC_{CREATE,REMOVE}_MINOR ioctl
entry points have been re-added. They now call directly in
to the ZVOL to create the needed minor node and add the sysfs
entried for udev.
Also as part of this change I've decided it would really be
best if all the zvols were in a /dev/zvol directory like on
Solaris. Organizationally this makes sense and on the code
side it allows us to know a block device is a zvol simply by
where it is located in /dev/. Unless Solaris there still is
to ./dsk or ./rdsk as part of the path.
The splat module is only needed for the spl regression tests.
But if we add it to MODULES then 'zfs.sh -u' will be able to
unload it if needed, The downside if 'zfs.sh' will always
load it but it's overhead is minimal and in a production
setting you'll always be doing a 'modprobe zfs' anyway so
this is really just for testing.
Extend the Makefiles with an uninstall target to cleanly
remove a package which was installed with 'make install'.
Additionally, ensure a 'depmod -a' is run as part of the
install to update the module dependency information.
The common.sh script assumed that it was either being run from
in-tree or was installed under /usr/libexec/zfs. If this was
not the case, because of say the default --prefix=/usr/local,
then the paths would be wrong. To fix this common.sh is now
generated from common.sh.in with the correct path information
provided at configure time.
The long term fix for Debian and Slackware style packaging is
to add native support for building these packages. Unfortunately,
that is a large chunk of work I don't have time for right now.
That said it would be nice to have at least basic packages for
these distributions.
As a quick short/medium term solution I've settled on using alien
to convert the RPM packages to DEB or TGZ style packages. The
build system has been updated with the following build targets
which will first build RPM packages and then convert them as
needed to the target package type:
make rpm: Create .rpm packages
make deb: Create .deb packages
make tgz: Create .tgz packages
make pkg: Create the right package type for your distribution
The solution comes with lot of caveats and your mileage may vary.
But basically the big limitations are that the resulting packages:
1) Will not have the correct dependency information.
2) Will not include the kernel version in the release.
3) Will not handle all differences between distributions.
But the resulting packages should be easy to install and remove
from your system and take care of running 'depmod -a' and such.
As I said at the top this is not the right long term solution.
If any of the upstream distribution maintainers want to jump in
and help do this right for their distribution I'd love the help.
Some buggy NPTL threading implementations include the guard area within
the stack size allocations. In this case we need to allocate an extra
page to account for the guard area since we only have two pages of usable
stack on Linux. Added an autoconf test that detects such implementations
by running a test program designed to segfault if the bug is present.
Set a flag NPTL_GUARD_WITHIN_STACK that is tested to decide if extra
stack space must be allocated for the guard area.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Some buggy NPTL threading implementations include the guard area within
the stack size allocations. In this case we need to allocate an extra
page to account for the guard area since we only have two pages of usable
stack on Linux. Added an autoconf test that detects such implementations
by running a test program designed to segfault if the bug is present.
Set a flag NPTL_GUARD_WITHIN_STACK that is tested to decide if extra
stack space must be allocated for the guard area.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
The stack check implementation in older versions of gcc has
a fairly low default limit on STACK_CHECK_MAX_FRAME_SIZE of
roughly 4096. This results in numerous warning when it is
used with code which was designed to run in user space and
thus may be relatively stack heavy. The avoid these warnings,
which are fatal with -Werror, this patch targets the use of
-fstack-check to libraries which are compiled in both user
space and kernel space. The only utility which uses this
flag is ztest which is designed to simulate running in the
kernel and must meet the -fstack-check requirements. All
other user space utilities do not use -fstack-check.
warning: frame size too large for reliable stack checking
warning: try reducing the number of local variables
We should just make a best effort when removing zvol minors
from the system during destroy. Failure here should never
prevent the pool from being destroyed. For example, if a
pool is so heavily damaged it cannot be opened (part of the
minor removal) we still want to be able to destroy it. The
worst case here is we may orphan a few minors but even that
is unlikely and not particularly harmful.
For some reason which remains mysterious to me the shared library
which calls pthread_create() must be linked with -pthread. If this
is not done on 32-bit system the default ulimit stack size is used.
Surprisingly, on a 64-bit system the stack limit specified by the
pthread_attr is honored even when -pthread is not passed when linking
the shared library.
This was caught under Debian Lenny builds because they are one of
the few/only current distros based on a 2.6.26 kernel. In one
of the build conditionals I accidently failed to assign the
return code to rc before returning.
While in theory I like the idea of compiler warnings always being
fatal. In practice this causes problems when small harmless errors
cause build failures for end users. To handle this I've updated
the build system such that -Werror is only used when --enable-debug
is passed to configure. This is how I always build when developing
so I'll catch all build warnings and end users will not get stuck
by minor issues.
Noticed under Ubuntu kernel builds, there were two instances where
printf() was not called with a "%s" and instread directly printed
the string. This can potentially result in a crash and is considered
bad form by gcc. It has been fixed by adding the needed "%s".
As of autoconf-2.65 the AC_LANG_SOURCE source macro no longer
includes the confdef.h results when expanded. To handle this
simply explicitly include confdef.h in conftest.c. This will
cause two copies to of confdef.h to be added to the test for
earlier autoconf versions but this is not harmful.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Devices were only being created at module load time or when a
dataset was created. Similiar devices were not always being
removed at all the correct times. This patch updates all the
places where devices should either be created or removed. I'm
reasonably sure I got them all but if theres a case I missed
we can catch it with a follow up patch.
module load/unload
zfs create/remove
zpool import/export
zpool destroy
This patch also adds a simple regression test to zconfig.sh
to ensure zpool import/export is basically working properly.
This test specifically checks that devices are created
properly, removed after export, created after import, and
removed as a consequence of a zpool destroy.
With the recent ZVOL update zvol_set_volblocksize() accidentally
lost its mutex_exit(). This was noticed when zvol_create_minor()
blocked on the zvol_state_lock while it was holding the
spa_namespace_lock(). This caused everything to get blocked
up and hung the system.
It seems the upstream community moved the definition of UTS_RELEASE
yet again as of linux-2.6.33. Update the build system to check in
all three possible locations where your kernel version may be defined.
$kernelbuild/include/linux/version.h
$kernelbuild/include/linux/utsrelease.h
$kernelbuild/include/generated/utsrelease.h
Brian Behlendorf
Ned Bass
Lars Johannsen