One of the side effects of calling zvol_create_minors() in
zvol_init() is that all pools listed in the cache file will
be opened. Depending on the state and contents of your pool
this operation can take a considerable length of time.
Doing this at load time is undesirable because the kernel
is holding a global module lock. This prevents other modules
from loading and can serialize an otherwise parallel boot
process. Doing this after module inititialization also
reduces the chances of accidentally introducing a race
during module init.
To ensure that /dev/zvol/<pool>/<dataset> devices are
still automatically created after the module load completes
a udev rules has been added. When udev notices that the
/dev/zfs device has been create the 'zpool list' command
will be run. This then will cause all the pools listed
in the zpool.cache file to be opened.
Because this process in now driven asynchronously by udev
there is the risk of problems in downstream distributions.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #756
Issue #1020
Issue #1234
The following error will occur on some (possibly all) kernels
because blk_init_queue() will try to take the spinlock before
we initialize it.
BUG: spinlock bad magic on CPU#0, zpool/4054
lock: 0xffff88021a73de60, .magic: 00000000,
.owner: <none>/-1, .owner_cpu: 0
Pid: 4054, comm: zpool Not tainted 3.9.3 #11
Call Trace:
[<ffffffff81478ef8>] spin_dump+0x8c/0x91
[<ffffffff81478f1e>] spin_bug+0x21/0x26
[<ffffffff812da097>] do_raw_spin_lock+0x127/0x130
[<ffffffff8147d851>] _raw_spin_lock_irq+0x21/0x30
[<ffffffff812c2c1e>] cfq_init_queue+0x1fe/0x350
[<ffffffff812aacb8>] elevator_init+0x78/0x140
[<ffffffff812b2677>] blk_init_allocated_queue+0x87/0xb0
[<ffffffff812b26d5>] blk_init_queue_node+0x35/0x70
[<ffffffff812b271e>] blk_init_queue+0xe/0x10
[<ffffffff8125211b>] __zvol_create_minor+0x24b/0x620
[<ffffffff81253264>] zvol_create_minors_cb+0x24/0x30
[<ffffffff811bd9ca>] dmu_objset_find_spa+0xea/0x510
[<ffffffff811bda71>] dmu_objset_find_spa+0x191/0x510
[<ffffffff81253ea2>] zvol_create_minors+0x92/0x180
[<ffffffff811f8d80>] spa_open_common+0x250/0x380
[<ffffffff811f8ece>] spa_open+0xe/0x10
[<ffffffff8122817e>] pool_status_check.part.22+0x1e/0x80
[<ffffffff81228a55>] zfsdev_ioctl+0x155/0x190
[<ffffffff8116a695>] do_vfs_ioctl+0x325/0x5a0
[<ffffffff8116a950>] sys_ioctl+0x40/0x80
[<ffffffff814812c9>] ? do_page_fault+0x9/0x10
[<ffffffff81483929>] system_call_fastpath+0x16/0x1b
zd0: unknown partition table
We fix this by calling spin_lock_init before blk_init_queue.
The manner in which zvol_init() initializes structures is
suspectible to a race between initialization and a probe on
a zvol. We reorganize zvol_init() to prevent that.
Signed-off-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
There is an extremely odd bug that causes zvols to fail to appear on
some systems, but not others. Recently, I was able to consistently
reproduce this issue over a period of 1 month. The issue disappeared
after I applied this change from FreeBSD.
This is from FreeBSD's pool version 28 import, which occurred in
revision 219089.
Ported-by: Richard Yao <ryao@cs.stonybrook.edu>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #441
Issue #599
3122 zfs destroy filesystem should prefetch blocks
Reviewed by: Christopher Siden <chris.siden@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Adam Leventhal <ahl@delphix.com>
Approved by: Garrett D'Amore <garrett@damore.org>
References:
illumos/illumos-gate@b4709335aahttps://www.illumos.org/issues/3122
Ported-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#1565
Commit 55d85d5a8c (backport of
the upstream changes) replaced three hardcoded constants:
#define SYNC_PASS_DEFERRED_FREE 2 /* defer frees after this pass */
#define SYNC_PASS_DONT_COMPRESS 4 /* don't compress after this pass */
#define SYNC_PASS_REWRITE 1 /* rewrite new bps after this pass */
with a tunable parameters:
int zfs_sync_pass_deferred_free = 2; /* defer frees starting in this pass */
int zfs_sync_pass_dont_compress = 5; /* don't compress starting in this pass */
int zfs_sync_pass_rewrite = 2; /* rewrite new bps starting in this pass */
This commit makes these tunables available as module parameters
in Linux. They should only be used for performance analysis
because changing them can result in subtle and pathological
performance problems.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#1562
The approach taken was the rework zfs_holey() as little as
possible and then just wrap the code as needed to ensure
correct locking and error handling.
Tested with xfstests 285 and 286. All tests pass except for
7-9 of 285 which try to reserve blocks first via fallocate(2)
and fail because fallocate(2) is not yet supported.
Note that the filp->f_lock spinlock did not exist prior to
Linux 2.6.30, but we avoid the need for autotools check by
virtue of the fact that SEEK_DATA/SEEK_HOLE support was not
added until Linux 3.1.
An autoconf check was added for lseek_execute() which is
currently a private function but the expectation is that it
will be exported perhaps as early as Linux 3.11.
Reviewed-by: Richard Laager <rlaager@wiktel.com>
Signed-off-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#1384
This patch restores the zfs_holey() function from OpenSolaris.
This was removed by commit 3558fd7 because it wasn't clear we
had a use for it in ZoL. However, this functionality is a
prerequisite for adding SEEK_DATA/SEEK_HOLE support to the ZPL.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Richard Yao <ryao@gentoo.org>
Issue #1384
By definitition these allocations will never fail. For
consistency with the rest of the code remove this dead error
handling code.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#1558
Fix a pair of conditions in which a concurrent umount can cause
NULL pointer dereferences:
* zfs_sb_teardown - prevent a NULL dereference by not calling
dmu_objset_pool with a null z_os.
* zfs_resume_fs - don't try to unmount with a null z_os. This
change makes the ZoL code more consistent
with both Illumos and FreeBSD.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#1543
Previous commit 7ef5e54e2e caused
module probe failure on 32-bit systems, dmesg showed
Unknown symbol __moddi3
This was caused by the modulo operation 'gethrtime() % tqs->stqs_count'
in the committed code. Instead of implementing __moddi3 for all 32-bit
systems, Behlendorf advised we can just cast the return value of
gethrtime() into a uint64_t, since gethrtime does not return negative
value on all circumstances we need not care about the potential overflow.
Signed-off-by: Ying Zhu <casualfisher@gmail.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#1551
Until these hooks are fully implemented return the expected
-EOPNOTSUPP error to indicate they are not functional. This
allows test suites such as xfstests to cleanly skip testing
this functionality until it's implemented.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #229
3805 arc shouldn't cache freed blocks
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Christopher Siden <christopher.siden@delphix.com>
Reviewed by: Richard Elling <richard.elling@dey-sys.com>
Reviewed by: Will Andrews <will@firepipe.net>
Approved by: Dan McDonald <danmcd@nexenta.com>
References:
illumos/illumos-gate@6e6d5868f5https://www.illumos.org/issues/3805
ZFS should proactively evict freed blocks from the cache.
On dcenter, we saw that we were caching ~256GB of metadata, while the
pool only had <4GB of metadata on disk. We were wasting about half the
system's RAM (252GB) on blocks that have been freed.
Even though these freed blocks will never be used again, and thus will
eventually be evicted, this causes us to use memory inefficiently for 2
reasons:
1. A block that is freed has no chance of being accessed again, but will
be kept in memory preferentially to a block that was accessed before it
(and is thus older) but has not been freed and thus has at least some
chance of being accessed again.
2. We partition the ARC into several buckets:
user data that has been accessed only once (MRU)
metadata that has been accessed only once (MRU)
user data that has been accessed more than once (MFU)
metadata that has been accessed more than once (MFU)
The user data vs metadata split is somewhat arbitrary, and the primary
control on how much memory is used to cache data vs metadata is to
simply try to keep the proportion the same as it has been in the past
(each bucket "evicts against" itself). The secondary control is to
evict data before evicting metadata.
Because of this bucketing, we may end up with one bucket mostly
containing freed blocks that are very old, while another bucket has more
recently accessed, still-allocated blocks. Data in the useful bucket
(with still-allocated blocks) may be evicted in preference to data in
the useless bucket (with old, freed blocks).
On dcenter, we saw that the MFU metadata bucket was 230MB, while the MFU
data bucket was 27GB and the MRU metadata bucket was 256GB. However,
the vast majority of data in the MRU metadata bucket (256GB) was freed
blocks, and thus useless. Meanwhile, the MFU metadata bucket (230MB)
was constantly evicting useful blocks that will be soon needed.
The problem of cache segmentation is a larger problem that needs more
investigation. However, if we stop caching freed blocks, it should
reduce the impact of this more fundamental issue.
Ported-by: Richard Yao <ryao@cs.stonybrook.edu>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#1503
3552 condensing one space map burns 3 seconds of CPU in spa_sync() thread
3564 spa_sync() spends 5-10% of its time in metaslab_sync() (when not condensing)
Reviewed by: Adam Leventhal <ahl@delphix.com>
Reviewed by: Dan Kimmel <dan.kimmel@delphix.com>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Approved by: Richard Lowe <richlowe@richlowe.net>
References:
illumos/illumos-gate@16a4a80742https://www.illumos.org/issues/3552https://www.illumos.org/issues/3564
Ported-by: Tim Chase <tim@chase2k.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#1513
3006 VERIFY[S,U,P] and ASSERT[S,U,P] frequently check if first
argument is zero
Reviewed by Matt Ahrens <matthew.ahrens@delphix.com>
Reviewed by George Wilson <george.wilson@delphix.com>
Approved by Eric Schrock <eric.schrock@delphix.com>
References:
illumos/illumos-gate@fb09f5aad4https://illumos.org/issues/3006
Requires:
zfsonlinux/spl@1c6d149feb
Ported-by: Tim Chase <tim@chase2k.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#1509
When SA xattrs are enabled only fallback to checking the directory
xattrs when the name is not found as a SA xattr. Otherwise, the SA
error which should be returned to the caller is overwritten by the
directory xattr errors. Positive return values indicating success
will also be immediately returned.
In the case of #1437 the ERANGE error was being correctly returned
by zpl_xattr_get_sa() only to be overridden with ENOENT which was
returned by the subsequent unnessisary call to zpl_xattr_get_dir().
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#1437
As a part of scrub/resilver tuning zfs_scrub_limit fell out of use,
but the definition of the variable remained in place.
Moreover various guides still (misleadingly) mention it as a way
to influence resilver/scrub behavior.
This commit removes its finally.
Signed-off-by: Cyril Plisko <cyril.plisko@mountall.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#1444
The assertions in ddt_phys_decref and ddt_sync_entry cast ddp->ddp_refcnt
from uint64_t to int64_t, with a reference count bigger than 2^63, e.g. the
reference count of zero blocks commonly available in spare files, we may
mistakenly hit these assertations, so drop the type conversions here.
Signed-off-by: Ying Zhu <casualfisher@gmail.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#1436
The vn_rdwr() function performs I/O by calling the vfs_write() or
vfs_read() functions. These functions reside just below the system
call layer and the expectation is they have almost the entire 8k of
stack space to work with. In fact, certain layered configurations
such as ext+lvm+md+multipath require the majority of this stack to
avoid stack overflows.
To avoid this posibility the vn_rdwr() call in dump_bytes() has been
moved to the ZIO_TYPE_FREE, taskq. This ensures that all I/O will be
performed with the majority of the stack space available. This ends
up being very similiar to as if the I/O were issued via sys_write()
or sys_read().
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#1399Closes#1423
3581 spa_zio_taskq[ZIO_TYPE_FREE][ZIO_TASKQ_ISSUE]->tq_lock is piping hot
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Christopher Siden <christopher.siden@delphix.com>
Reviewed by: Gordon Ross <gordon.ross@nexenta.com>
Approved by: Richard Lowe <richlowe@richlowe.net>
References:
illumos/illumos-gate@ec94d32https://illumos.org/issues/3581
Notes for Linux port:
Earlier commit 08d08eb reduced contention on this taskq lock by simply
reducing the number of z_fr_iss threads from 100 to one-per-CPU. We
also optimized the taskq implementation in zfsonlinux/spl@3c6ed54.
These changes significantly improved unlink performance to acceptable
levels.
This patch further reduces time spent spinning on this lock by
randomly dispatching the work items over multiple independent task
queues. The Illumos ZFS developers stated that this lock contention
only arose after "3329 spa_sync() spends 10-20% of its time in
spa_free_sync_cb()" was landed. It's not clear if 3329 affects the
Linux port or not. I didn't see spa_free_sync_cb() show up in
oprofile sessions while unlinking large files, but I may just not
have used the right test case.
I tested unlinking a 1 TB of data with and without the patch and
didn't observe a meaningful difference in elapsed time. However,
oprofile showed that the percent time spent in taskq_thread() was
reduced from about 16% to about 5%. Aside from a possible slight
performance benefit this may be worth landing if only for the sake of
maintaining consistency with upstream.
Ported-by: Ned Bass <bass6@llnl.gov>
Closes#1327
3329 spa_sync() spends 10-20% of its time in spa_free_sync_cb()
3330 space_seg_t should have its own kmem_cache
3331 deferred frees should happen after sync_pass 1
3335 make SYNC_PASS_* constants tunable
Reviewed by: Adam Leventhal <ahl@delphix.com>
Reviewed by: Matt Ahrens <matthew.ahrens@delphix.com>
Reviewed by: Christopher Siden <chris.siden@delphix.com>
Reviewed by: Eric Schrock <eric.schrock@delphix.com>
Reviewed by: Richard Lowe <richlowe@richlowe.net>
Reviewed by: Dan McDonald <danmcd@nexenta.com>
Approved by: Eric Schrock <eric.schrock@delphix.com>
References:
illumos/illumos-gate@01f55e48fbhttps://www.illumos.org/issues/3329https://www.illumos.org/issues/3330https://www.illumos.org/issues/3331https://www.illumos.org/issues/3335
Ported-by: Brian Behlendorf <behlendorf1@llnl.gov>
3306 zdb should be able to issue reads in parallel
3321 'zpool reopen' command should be documented in the man
page and help
Reviewed by: Adam Leventhal <ahl@delphix.com>
Reviewed by: Matt Ahrens <matthew.ahrens@delphix.com>
Reviewed by: Christopher Siden <chris.siden@delphix.com>
Approved by: Garrett D'Amore <garrett@damore.org>
References:
illumos/illumos-gate@31d7e8fa33https://www.illumos.org/issues/3306https://www.illumos.org/issues/3321
The vdev_file.c implementation in this patch diverges significantly
from the upstream version. For consistenty with the vdev_disk.c
code the upstream version leverages the Illumos bio interfaces.
This makes sense for Illumos but not for ZoL for two reasons.
1) The vdev_disk.c code in ZoL has been rewritten to use the
Linux block device interfaces which differ significantly
from those in Illumos. Therefore, updating the vdev_file.c
to use the Illumos interfaces doesn't get you consistency
with vdev_disk.c.
2) Using the upstream patch as is would requiring implementing
compatibility code for those Solaris block device interfaces
in user and kernel space. That additional complexity could
lead to confusion and doesn't buy us anything.
For these reasons I've opted to simply move the existing vn_rdwr()
as is in to the taskq function. This has the advantage of being
low risk and easy to understand. Moving the vn_rdwr() function
in to its own taskq thread also neatly avoids the possibility of
a stack overflow.
Finally, because of the additional work which is being handled by
the free taskq the number of threads has been increased. The
thread count under Illumos defaults to 100 but was decreased to 2
in commit 08d08e due to contention. We increase it to 8 until
the contention can be address by porting Illumos #3581.
Ported-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#1354
Reviewed by: Matt Ahrens <matthew.ahrens@delphix.com>
Reviewed by: Eric Schrock <eric.schrock@delphix.com>
Reviewed by: Christopher Siden <chris.siden@delphix.com>
Approved by: Garrett D'Amore <garrett@damore.org>
NOTES: This patch has been reworked from the original in the
following ways to accomidate Linux ZFS implementation
*) Usage of the cyclic interface was replaced by the delayed taskq
interface. This avoids the need to implement new compatibility
code and allows us to rely on the existing taskq implementation.
*) An extern for zfs_txg_synctime_ms was added to sys/dsl_pool.h
because declaring externs in source files as was done in the
original patch is just plain wrong.
*) Instead of panicing the system when the deadman triggers a
zevent describing the blocked vdev and the first pending I/O
is posted. If the panic behavior is desired Linux provides
other generic methods to panic the system when threads are
observed to hang.
*) For reference, to delay zios by 30 seconds for testing you can
use zinject as follows: 'zinject -d <vdev> -D30 <pool>'
References:
illumos/illumos-gate@283b84606bhttps://www.illumos.org/issues/3246
Ported-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#1396
A deadlock was accidentally introduced by commit e95853a which
can occur when the system is under memory pressure. What happens
is that while the txg_quiesce thread is holding the tx->tx_cpu
locks it enters memory reclaim. In the context of this memory
reclaim it then issues synchronous I/O to a ZVOL swap device.
Because the txg_quiesce thread is holding the tx->tx_cpu locks
a new txg cannot be opened to handle the I/O. Deadlock.
The fix is straight forward. Move the memory allocation outside
the critical region where the tx->tx_cpu locks are held. And for
good measure change the offending allocation to KM_PUSHPAGE to
ensure it never attempts to issue I/O during reclaim.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #1274
According to the getxattr(2) man page the ERANGE errno should be
returned when the size of the value buffer is to small to hold the
result. Prior to this patch the implementation would just truncate
the value to size bytes.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#1408
The zpl_readdir() function shouldn't be registered as part of
the zpl_file_operations table, it must only be part of the
zpl_dir_file_operations table. By removing this callback
the VFS will now correctly return ENOTDIR when calling
getdents() on a file.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#1404
Previous patches have allowed you to set an increased ashift to
avoid doing 512b IO with 4k sector devices. However, it was not
possible to set the ashift lower than the reported physical sector
size even when a smaller logical size was supported. In practice,
there are several cases where settong a lower ashift is useful:
* Most modern drives now correctly report their physical sector
size as 4k. This causes zfs to correctly default to using a 4k
sector size (ashift=12). However, for some usage models this
new default ashift value causes an unacceptable increase in
space usage. Filesystems with many small files may see the
total available space reduced to 30-40% which is unacceptable.
* When replacing a drive in an existing pool which was created
with ashift=9 a modern 4k sector drive cannot be used. The
'zpool replace' command will issue an error that the new drive
has an 'incompatible sector alignment'. However, by allowing
the ashift to be manual specified as smaller, non-optimal,
value the device may still be safely used.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#1381Closes#1328
Issue #967
Issue #548
3422 zpool create/syseventd race yield non-importable pool
3425 first write to a new zvol can fail with EFBIG
Reviewed by: Adam Leventhal <ahl@delphix.com>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Approved by: Garrett D'Amore <garrett@damore.org>
References:
illumos/illumos-gate@bda8819455https://www.illumos.org/issues/3422https://www.illumos.org/issues/3425
Ported-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#1390
The assumption in zio_ddt_free() is that ddt_phys_select() must
always find a match. However, if that fails due to a damaged
DDT or some other reason the code will NULL dereference in
ddt_phys_decref().
While this should never happen it has been observed on various
platforms. The result is that unless your willing to patch the
ZFS code the pool is inaccessible. Therefore, we're choosing
to more gracefully handle this case rather than leave it fatal.
http://mail.opensolaris.org/pipermail/zfs-discuss/2012-February/050972.html
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#1308
Enabling metaslab debugging will prevent space maps from being
automatically unloaded. This can significantly increase the
memory footprint but being able to dynamically control this is
helpful for debugging and certain performance testing.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
The mainline kernel started defining GCC_VERSION with commit
torvalds/linux@3f3f8d2f48.
Unfortunately, LZ4 also defines this macro, but the two
defintions are incompatible. We undefine GCC_VERSION in lz4.c
to handle this.
Signed-off-by: Richard Yao <ryao@cs.stonybrook.edu>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#1339
The new snapdev dataset property may be set to control the
visibility of zvol snapshot devices. By default this value
is set to 'hidden' which will prevent zvol snapshots from
appearing under /dev/zvol/ and /dev/<dataset>/. When set to
'visible' all zvol snapshots for the dataset will be visible.
This functionality was largely added because when automatic
snapshoting is enabled large numbers of read-only zvol snapshots
will be created. When creating these devices the kernel will
attempt to read their partition tables, and blkid will attempt
to identify any filesystems on those partitions. This leads
to a variety of issues:
1) The zvol partition tables will be read in the context of
the `modprobe zfs` for automatically imported pools. This
is undesirable and should be done asynchronously, but for
now reducing the number of visible devices helps.
2) Udev expects to be able to complete its work for a new
block devices fairly quickly. When many zvol devices are
added at the same time this is no longer be true. It can
lead to udev timeouts and missing /dev/zvol links.
3) Simply having lots of devices in /dev/ can be aukward from
a management standpoint. Hidding the devices your unlikely
to ever use helps with this. Any snapshot device which is
needed can be made visible by changing the snapdev property.
NOTE: This patch changes the default behavior for zvols which
was effectively 'snapdev=visible'.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#1235Closes#945
Issue #956
Issue #756
The changes to zvol.c were never merged from the last onnv_147
bulk update. This was because zvol.c was largely rewritten
for Linux making it fairly easy to miss these sorts of changes.
This causes a regression when importing a zpool with zvols
read-only. This does not impact pool which only contain
filesystem datasets.
References:
illumos/illumos-gate@f9af39b
Signed-off-by: Richard Yao <ryao@cs.stonybrook.edu>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#1332Closes#1333
The PaX team modified the kernel's modpost to report writeable function
pointers as section mismatches because they are potential exploit
targets. We could ignore the warnings, but their presence can obscure
actual issues. Proper const correctness can also catch programming
mistakes.
Building the kernel modules against a PaX/GrSecurity patched Linux 3.4.2
kernel reports 133 section mismatches prior to this patch. This patch
eliminates 130 of them. The quantity of writeable function pointers
eliminated by constifying each structure is as follows:
vdev_opts_t 52
zil_replay_func_t 24
zio_compress_info_t 24
zio_checksum_info_t 9
space_map_ops_t 7
arc_byteswap_func_t 5
The remaining 3 writeable function pointers cannot be addressed by this
patch. 2 of them are in zpl_fs_type. The kernel's sget function requires
that this be non-const. The final writeable function pointer is created
by SPL_SHRINKER_DECLARE. The kernel's set_shrinker() and
remove_shrinker() functions also require that this be non-const.
Signed-off-by: Richard Yao <ryao@cs.stonybrook.edu>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#1300
The issue with hot spares in ZoL is because it opens all leaf
vdevs exclusively (O_EXCL). On Linux, exclusive opens cause
subsequent exclusive opens to fail with EBUSY.
This could be resolved by not opening any of the devices
exclusively, which is what Illumos does, but the additional
protection offered by exclusive opens is desirable. It cleanly
prevents you from accidentally adding an in-use non-ZFS device
to your pool.
To fix this we very slightly relaxed the usage of O_EXCL in
the following ways.
1) Functions which open the device but only read had the
O_EXCL flag removed and were updated to use O_RDONLY.
2) A common holder was added to the vdev disk code. This
allow the ZFS code to internally open the device multiple
times but non-ZFS callers may not.
3) An exception was added to make_disks() for hot spare when
creating partition tables. For hot spare devices which
are already opened exclusively we skip creating the partition
table because this must already have been done when the disk
was originally added as a hot spare.
Additional minor changes include fixing check_in_use() to use
a partition instead of a slice suffix. And is_spare() was moved
above make_disks() to avoid adding a forward reference.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#250
As described by the comment and enforced the by assertion the
v->vdev_wholedisk will never be -1. The wholedisk handling
is performed by the user space utilities. To prevent confusion
this dead code is being removed.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
When vdev_disk.c was implemented for Linux we failed to handle the
reopen case. According to the vdev_reopen() comment leaf vdevs should
not be closed or opened when v->vdev_reopening is set. Under Linux
we would always close and open the device.
This issue was only noticed when a 'zpool scrub' command was run while
the leaf vdev device names in /dev/disk/by-vdev were missing. The
scrub command calls vdev_reopen() which caused the vdevs to be closed
but they couldn't be reopened due to the missing links. The result
was that all the vdevs were marked unavailable and the pool was
halted due to failmode=wait.
This patch adds the missing functionality in a similiar fashion to
to the Illumos code.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
To determine whether the kernel is capable of handling empty barrier
BIOs, we check for the presence of the bio_empty_barrier() macro,
which was introduced in 2.6.24. If this macro is defined, then we can
flush disk vdevs; if it isn't, then flushing is disabled.
Unfortunately, the bio_empty_barrier() macro was removed in 2.6.37,
even though the kernel is still capable of handling empty barrier BIOs.
As a result, flushing is effectively disabled on kernels >= 2.6.37,
meaning that starting from this kernel version, zfs doesn't use
barriers to guarantee on-disk data consistency. This is quite bad and
can lead to potential data corruption on power failures.
This patch fixes the issue by removing the configure check for
bio_empty_barrier(), as we don't support kernels <= 2.6.24 anymore.
Thanks to Richard Kojedzinszky for catching this nasty bug.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#1318
The zfs_arc_memory_throttle_disable module option was introduced
by commit 0c5493d470 to resolve a
memory miscalculation which could result in the txg_sync thread
spinning.
When this was first introduced the default behavior was left
unchanged until enough real world usage confirmed there were no
unexpected issues. We've now reached that point. Linux's
direct reclaim is working as expected so we're enabling this
behavior by default.
This helps pave the way to retire the spl_kmem_availrmem()
functionality in the SPL layer. This was the only caller.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #938
A couple of assertions in spa.c were designed to prevent the use of
invalid pool versions. They were written under the assumption
that all valid pools are less than SPA_VERSION. Since feature flags
jumped from 28 to 5000, any numbers in the range 28 to 5000
non-inclusive will fail to trigger them. We switch to the new
SPA_VERSION_IS_SUPPORTED macro to correct this.
Signed-off-by: Richard Yao <ryao@cs.stonybrook.edu>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#1282
It turns out that the Linux VFS doesn't strictly handle all cases
where a component path name exceeds MAXNAMELEN. It does however
appear to correctly handle MAXPATHLEN for us.
The right way to handle this appears to be to add an explicit
check to the zpl_lookup() function. Several in-tree filesystems
handle this case the same way.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#1279
Two more locations where KM_SLEEP was used in a call which must
use KM_PUSHPAGE were found while using the zpool upgrade command.
See commit b8d06fc for additional details.
Also make a small correction to the comment block above
dsl_dir_open_spa().
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#1268
Explicitly case this value to an unsigned long long for 32-bit
systems to inform the compiler that a long type should not be
used. Otherwise we get the following compiler error:
dmu_send.c:376: error: integer constant is too large for
‘long’ type
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
The way in which virtual box ab(uses) memory can throw off the
free memory calculation in arc_memory_throttle(). The result is
the txg_sync thread will effectively spin waiting for memory to
be released even though there's lots of memory on the system.
To handle this case I'm adding a zfs_arc_memory_throttle_disable
module option largely for virtual box users. Setting this option
disables free memory checks which allows the txg_sync thread to
make progress.
By default this option is disabled to preserve the current
behavior. However, because Linux supports direct memory reclaim
it's doubtful throttling due to perceived memory pressure is ever
a good idea. We should enable this option by default once we've
done enough real world testing to convince ourselve there aren't
any unexpected side effects.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#938
Commit 1eb5bfa introduced a new zfs_disable_dup_eviction tunable.
It should have been made available as a module option in the
original patch but was overlooked.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
When a system attribute layout is created an inconsistency may occur
between the system attribute header (sa_hdr_phys_t) size and the
variable-sized attribute count stored in the layout. The inconsistency
results in the following failed assertion when SA_HDR_SIZE_MATCH_LAYOUT
returns false:
SPLError: 11315:0:(sa.c:1541:sa_find_idx_tab())
ASSERTION((IS_SA_BONUSTYPE(bonustype) && SA_HDR_SIZE_MATCH_LAYOUT(hdr,
tb)) || !IS_SA_BONUSTYPE(bonustype) || (IS_SA_BONUSTYPE(bonustype) &&
hdr->sa_layout_info == 0)) failed
The bug originates in this snippet from sa_find_sizes().
if (is_var_sz && var_size > 1) {
if (P2ROUNDUP(hdrsize + sizeof (uint16_t),
*total < full_space) {
hdrsize += sizeof (uint16_t);
This assumes that the current variable-sized attribute will be stored in
the current buffer and accounts for the space needed to store its size
in the sa_hdr_phys_t. However if the next attribute spills over we need
to store a blkptr_t at the end of the bonus buffer to point to the spill
block. If the current attribute is in the way of the blkptr_t then it
too will be relocated into the spill block. But since we've already
accounted for it in the header size we get the inconsistency described
above.
To avoid this, record the index of the last variable-sized attribute
that prompted a hdrsize increase, and reverse the increase if we later
determine that that attribute will be relocated to the spill block.
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#1250
A rounding discrepancy exists between how sa_build_layouts() and
sa_find_sizes() calculate when the spill block needs to be kicked in.
This results in a narrow size range where sa_build_layouts() believes
there must be a spill block allocated but due to the discrepancy there
isn't. A panic then occurs when the hdl->sa_spill NULL pointer is
dereferenced.
The following reproducer for this bug was isolated:
truncate -s 128m /tmp/tank
zpool create tank /tmp/tank
zfs create -o xattr=sa tank/fish
ln -s `perl -e 'print "z" x 41'` /tank/fish/z
setfattr -hn trusted.foo -v`perl -e 'print "z"x45'` /tank/fish/z
This test results in roughly the following system attribute (SA)
layout:
176 bytes - "standard" SA's
41 bytes - name of symbolic link target
100 bytes - XDR encoded nvlist for xattr
---
317 bytes - total
Because 317 is less than DN_MAX_BONUSLEN (320), sa_find_sizes()
decides no spill block is needed. But sa_build_layouts() rounds 41 up
to 48 when computing the space requirements so it tries to switch to
the spill block.
Note that we were only able to reproduce this bug using a combination
of symbolic links and the Linux-specific xattr=sa dataset property.
So while this issue is not technically Linux-specific, it may be
difficult or impossible to hit the narrow size range needed to
reproduce it on other platforms.
To fix the discrepancy, round the running total in sa_find_sizes() up
to an 8-byte boundary before accounting for each SA, since this is how
they will be stored in the bonus and (possibly) spill buffers.
To make the intent of the code more clear, explicitly assert key
assumptions about expected alignment of data and whether spill-over
will occur.
Signed-off-by: Matthew Ahrens <mahrens@delphix.com
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#1240
