The uid_t on most systems is in fact and unsigned 32-bit value.
This is almost always correct, however you could compile your
kernel to use an unsigned 16-bit value for uid_t. In practice
I've never encountered a distribution which does this so I'm
willing to overlook this corner case for now.
Closes#165
The vdev_metaslab_init() function has been observed to allocate
larger than 8k chunks. However, they are not much larger than 8k
and it does this infrequently so it is allowed and the warning is
supressed.
The dsl_scan_visit() function is a little heavy weight taking 464
bytes on the stack. This can be easily reduced for little cost by
moving zap_cursor_t and zap_attribute_t off the stack and on to the
heap. After this change dsl_scan_visit() has been reduced in size
by 320 bytes.
This change was made to reduce stack usage in the dsl_scan_sync()
callpath which is recursive and has been observed to overflow the
stack.
Issue #174
This function is called recursively so everything possible must be
done to limit its stack consumption. The dprintf_bp() debugging
function adds 30 bytes of local variables to the function we cannot
afford. By commenting out this debugging we save 30 bytes per
recursion and depths of 13 are not uncommon. This yeilds a total
stack saving of 390 bytes on our 8k stack.
Issue #174
The recursive call chain dsl_scan_visitbp() -> dsl_scan_recurse() ->
dsl_scan_visitdnode() -> dsl_scan_visitbp has been observed to consume
considerable stack resulting in a stack overflow (>8k). The cleanest
way I see to fix this with minimal impact to the existing flow of
code, and with the fewest performance concerns, is to always inline
dsl_scan_recurse() and dsl_scan_visitdnode(). While this will increase
the function size of dsl_scan_visitbp(), by 4660 bytes, it also reduces
the stack requirements by removing the function call overhead.
Issue #174
It's possible for a zvol_write thread to enter direct memory reclaim
while holding open a transaction group. This results in the system
attempting to write out data to the disk to free memory. Unfortunately,
this can't succeed because the the thread doing reclaim is holding open
the txg which must be closed to be synced to disk. To prevent this
the offending allocation is marked KM_PUSHPAGE which will prevent it
from attempting writeback.
Closes#191
Disable the gethostid() override for Solaris behavior because Linux systems
implement the POSIX standard in a way that allows a negative result.
Mask the gethostid() result to the lower four bytes, like coreutils does in
/usr/bin/hostid, to prevent junk bits or sign-extension on systems that have an
eight byte long type. This can cause a spurious hostid mismatch that prevents
zpool import on 64-bit systems.
Having MAXOFFSET_T defined to 0x7fffffffl was artificially limiting
the maximum file size on 32-bit systems. In reality MAXOFFSET_T is
used when working with 'long long' types and as such we now define
it as LLONG_MAX. This resolves the 2GB file size limit for files
and additionally allows zvols greater than 2GB on 32-bit systems.
Closes#136Closes#81
Occasionally we would see an -EFAULT returned when setting the
I/O scheduler on a vdev. This was caused an improperly formatted
user mode helper command.
This commit restructures the command to something simpler, allocates
space for it dynamically to save stack, and removes the retry logic
which is no longer needed.
Closes#169
This change ensures the ARC meta-data limits are enforced. Without
this enforcement meta-data can grow to consume all of the ARC cache
pushing out data and hurting performance. The cache is aggressively
reclaimed but this is a soft and not a hard limit. The cache may
exceed the set limit briefly before being brought under control.
By default 25% of the ARC capacity can be used for meta-data. This
limit can be tuned by setting the 'zfs_arc_meta_limit' module option.
Once this limit is exceeded meta-data reclaim will occur in 3 percent
chunks, or may be tuned using 'arc_reduce_dnlc_percent'.
Closes#193
Fixed a bug where zfs_zget could access a stale znode pointer when
the inode had already been removed from the inode cache via iput ->
iput_final -> ... -> zfs_zinactive but the corresponding SA handle
was still alive.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#180
As part of zfs_ioc_recv() a zfs_cmd_t is allocated in the kernel
which is 17808 bytes in size. This sort of thing in general should
be avoided. However, since this should be an infrequent event for
now we allow it and simply suppress the warning with the KM_NODEBUG
flag. This can be revisited latter if/when it becomes an issue.
Closes#178
This change should have occured when we commited the new udev
rules for zvols. Basically, the test script is just out of date.
We need to update it to use the /dev/zvol/ device names, and
to expect the more common -partN suffixes.
I added a udev_trigger() call in zconfig_partition() and
zconfig_zvol_device_stat() to ensure that all the udev rules have
run before. This ensures the devices are available to subsequent
commands and closes a small race.
Finally, I was forced added a small 'sleep 1' to test 10. I
was observing occassional failures in my VM due to the device
still claiming to be busy. Delaying betwen the various methods
of adding/removing a vdev avoids the issue.
Closes#207
The zfault.sh and zconfig.sh test scripts requires the parted
utility, the lsscsi utility, and the scsi_debug module. To
ensure the utilities are available they have been added as
dependencies to zfs-test package. Checking for scsi_debug
is a little more problematic because if it's missing you will
need to build it. For clarity the documention has been updated
to mention this.
Closes#205Closes#206
If the attribute's new value was shorter than the old one the old
code would leave parts of the old value in the xattr znode.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#203
Without this we may mistakenly believe we have a dentry and try to
d_instantiate() it. This will result in the following BUG. It's
important to note that while the xattr directory has an inode
assoicated with it we never create a dentry for it.
kernel BUG at fs/dcache.c:1418!
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#202
As of gcc-4.6 the option -Wunused-but-set-variable is enabled by
default. While this is a useful warning there are numerous places
in the ZFS code when a variable is set and then only checked in an
ASSERT(). To avoid having to update every instance of this in the
code we now set -Wno-unused-but-set-variable to suppress the warning.
Additionally, when building with --enable-debug and -Werror set these
warning also become fatal. We can reevaluate the suppression of these
error at a later time if it becomes an issue. For now we are basically
just reverting to the previous gcc behavior.
Newer versions of gcc are getting smart enough to detect the sloppy
syntax used for the autoconf tests. It is now generating warnings
for unused/undeclared variables. Newer version of gcc even have
the -Wunused-but-set-variable option set by default. This isn't a
problem except when -Werror is set and they get promoted to an error.
In this case the autoconf test will return an incorrect result which
will result in a build failure latter on.
To handle this I'm tightening up many of the autoconf tests to
explicitly mark variables as unused to suppress the gcc warning.
Remember, all of the autoconf code can never actually be run we
just want to get a clean build error to detect which APIs are
available. Never using a variable is absolutely fine for this.
Closes#176
When compiling ZFS in user space gcc-4.6.0 correctly identifies
the variable 'value' as being set but never used. This generates a
warning and a build failure when using --enable-debug. Once again
this is correct but I'm reluctant to remove 'value' because we are
breaking the string in to name/value pairs. While it is not used
now there's a good chance it will be soon and I'd rather not have
to reinvent this. To suppress the warning with just as a VERIFY().
This was observed under Fedora 15.
cmd/mount_zfs/mount_zfs.c: In function ‘parse_option’:
cmd/mount_zfs/mount_zfs.c:112:21: error: variable ‘value’ set but not
used [-Werror=unused-but-set-variable]
When compiling ZFS in user space gcc-4.6.0 correctly identifies
the variable 'os' as being set but never used. This generates a
warning and a build failure when using --enable-debug. However,
the code is correct we only want to use 'os' for the kernel space
builds. To suppress the warning the call was wrapped with a
VERIFY() which has the nice side effect of ensuring the 'os'
actually never is NULL. This was observed under Fedora 15.
module/zfs/dsl_pool.c: In function ‘dsl_pool_create’:
module/zfs/dsl_pool.c:229:12: error: variable ‘os’ set but not used
[-Werror=unused-but-set-variable]
Update code to use the spl_invalidate_inodes() wrapper. This hides
some of the complexity of determining if invalidate_inodes() was
exported, and if so what is its prototype. The second argument
of spl_invalidate_inodes() determined the behavior of how dirty
inodes are handled. By passing a zero we are indicated that we
want those inodes to be treated as busy and skipped.
Several Makefile.in's were accidentally not updated when the
kernel-insert-inode-locked.m4 check was added. This change simply
refreshes the missed files.
When rebuilding the source RPM under el5 you need to append the
target_cpu. However, under el6/ch5 things are packaged correctly
and the arch is already part of kver. For this reason it also
needs to be stripped from kver when setting kverpkg.
The .sync_fs fix as applied did not use the updated SPL credential
API. This broke builds on Debian Lenny, this change applies the
needed fix to use the portable API. The original credential changes
are part of commit 81e97e2187.
Apply all of Rudd-O's changes for the Fedora init script. The
initial init script was one I threw together based on Rudd-O's
original work. It worked for me but it has some flaws.
Rudd-O has invested considerable time updating it to be significantly
smarter. It now handles using ZFS as your root filesystem plus
various other quirks. Since he is familiar with the right
way to do things on Fedora and has tested this init script we
are integrating all of his changes.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Disable the normal reclaim path for the txg_sync thread. This
ensures the thread will never enter dmu_tx_assign() which can
otherwise occur due to direct reclaim. If this is allowed to
happen the system can deadlock. Direct reclaim call path:
->shrink_icache_memory->prune_icache->dispose_list->
clear_inode->zpl_clear_inode->zfs_inactive->dmu_tx_assign
Under OpenSolaris all memory reclaim is done asyncronously. Under
Linux memory reclaim is done asynchronously _and_ synchronously.
When a process allocates memory with GFP_KERNEL it explicitly allows
the kernel to do reclaim on its behalf to satify the allocation.
If that GFP_KERNEL allocation fails the kernel may take more drastic
measures to reclaim the memory such as killing user space processes.
This was observed to happen with ZFS because the ARC could consume
a large fraction of the system memory but no synchronous reclaim
could be performed on it. The result was GFP_KERNEL allocations
could fail resulting in OOM events, and only moments latter the
arc_reclaim thread would free unused memory from the ARC.
This change leaves the arc_thread in place to manage the fundamental
ARC behavior. But it adds a synchronous (direct) reclaim path for
the ARC which can be called when memory is badly needed. It also
adds an asynchronous (indirect) reclaim path which is called
much more frequently to prune the ARC slab caches.
Alejandro R. Sedeño
Brian Behlendorf
Gunnar Beutner
Darik Horn
Aniruddha Shankar
Richard Laager
Ned Bass
Manuel Amador (Rudd-O)