It appears that in earlier kernels the maximum name length of a
kobject was KOBJ_NAME_LEN (20) bytes. This was later extended to
dynamically allocate enough memory if it was over KOBJ_NAME_LEN,
and finally it was always made dynamic. Unfortunately, util this
last step happened it doesn't look like it always safe to use
names larger than KOBJ_NAME_LEN. For example, under the RHEL5
2.6.18 kernel if the kobject name length exceeds KOBJ_NAME_LEN
a NULL dereference is tripped.
To avoid this issue the build system has been update to check
to see if KOBJ_NAME_LEN is defined. If it is we have to assume
the maximum kobject name length is only 20 bytes. This 20 byte
name must minimally include the following components.
<zpool>/<dataset>[@snapshot[partition]]
While the zfs utilities do block until the expected device appears
they can only do this for full devices, not partitions. This means
that once as device appears it still may take a little bit of time
before the kernel rescans the partition table, updates sysfs, udev
is notified and the partition devices are created. The test case
itself could block briefly waiting for the partition beause it knows
what to expect. But for now the simpler thing to do is just delay.
See previous commit for details. But the gist is with the removal of
the zvol path component the regression tests must be updated to use
the correct path name.
Interestingly this looks like an upstream bug as well. If for some
reason we are unable to get a zvols statistics, because perhaps the
zpool is hopelessly corrupt, we would trigger the VERIFY. This
commit adds the proper error handling just to propagate the error
back to user space. Now the user space tools still must handle this
properly but in the worst case the tool will crash or perhaps have
some missing output. That's far far better than crashing the host.
Closes#45
Several folks have now remarked that when the regression tests
fail they leave a mess behind. This was done intentionally at
the time to facilitate debugging the wreckage.
However, this also means that you may need to do some manual
cleanup such as removing the loopback devices before re-running
the tests. To simplify this proceedure I've added the '-c'
option to zconfig.sh which will attempt to cleanup the mess
from a previous test before starting.
This is somewhat dangerous because it must guess as to which
loopback devices you were using. But this risk is fairly minimal
because devices which are currently still is use can not be
cleaned up. And because only devices with 'zpool' in the name
are considered for removal. That said if your running parallel
copies of say zconfig.sh this may cause you some trouble.
Update the zconfig.sh test script to verify not only that volumes,
snapshots, and clones are created and removed properly. But also
verify that the partition information for each of these types of
devices is properly enumerated by the kernel.
Tests 4 and 5 now also create two partitions on the original volume
and these partitions are expected to also exist on the snapshot and
the clone. Correctness is verified after import/export, module
load/unload, dataset creation, and pool destruction.
Additionally, the code to create a partition table was refactored
in to a small helper function to simplify the test cases. And
finally all of the function variables were flagged 'local' to ensure
their scope is limited. This should have been done a while ago.
During spa_load the spl->spa_deferred_bpobj maybe be opened and closed
multiple times. It's critical that when the object is closed the
bpo->bpo_object is set to zero to indicate the object is closed.
If it's not during spl_load_retry the spl->spa_deferred_bpobj can
be closes twice resulting in a NULL deref.
This appears to have been fixed upstream the same way.
This reverts commit 411dd65af1.
gcc version 4.1.2 does not like having differing prototypes
for zio_execute, one version in the .c with inline and one
version in the .h without. Thus I'm reverting this change
and we'll see how critical this particular stack reduction is.
This commit preserves the recursive function dbuf_hold_impl() but moves
the local variables and function arguments to the heap to minimize
the stack frame size. Enough space is initially allocated on the
stack for 20 levels of recursion. This technique was based on commit
34229a2f2a which reduced stack usage of
traverse_visitbp().
dbuf_hold_impl() is mutually recursive with dbuf_findbp(),
but the latter function is also called from other functions.
Therefore dbuf_findbp() must contain logic to determine how to call
dbuf_hold_impl(). To this end, dbuf_hold_impl() now takes a
struct dbuf_hold_impl_data pointer as an argument. If that argument
is NULL it calls dbuf_hold_impl() as before, otherwise it calls
__debuf_hold_impl() with a single dbuf_hold_impl_data pointer argument.
As the name implies, dbuf_hold_impl_data stores the arguments and local
variables for dbuf_hold_impl().
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Github issue 22 reported a stack overrun when the zfs module was
loaded, possibly related to the presence of existing zpools created
under zfs-fuse. The stack trace showed 9 levels of recursion between
dsl_scan_visitbp() and dsl_scan_recurse(). To reduce stack overhead in
that code path, this commit moves the 128 byte blkptr_t data strucutre
in dsl_scan_visitbp() to the heap.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Eliminated local variables pointing to members of the zio struct.
Just refer to the struct members directly. This saved about 32 bytes per
call, but this function can be called recurisvely up to 19 levels deep,
so we potentially save up to 608 bytes.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Brian Behlendorf
Ned Bass