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
3035 LZ4 compression support in ZFS and GRUB
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Christopher Siden <christopher.siden@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Approved by: Christopher Siden <csiden@delphix.com>
References:
illumos/illumos-gate@a6f561b4aehttps://www.illumos.org/issues/3035http://wiki.illumos.org/display/illumos/LZ4+Compression+In+ZFS
This patch has been slightly modified from the upstream Illumos
version to be compatible with Linux. Due to the very limited
stack space in the kernel a lz4 workspace kmem cache is used.
Since we are using gcc we are also able to take advantage of the
gcc optimized __builtin_ctz functions.
Support for GRUB has been dropped from this patch. That code
is available but those changes will need to made to the upstream
GRUB package.
Lastly, several hunks of dead code were dropped for clarity. They
include the functions real_LZ4_uncompress(), LZ4_compressBound()
and the Visual Studio specific hunks wrapped in _MSC_VER.
Ported-by: Eric Dillmann <eric@jave.fr>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#1217
Explicitly set acl details to zero to silence gcc (zfs_acl_node_read
can't be sure zfs_acl_znode_info will set acl_count and aclsize).
Normally suppressing these warnings by setting this to zero at
declaration time is a bad idea but in this instance it's hard to
avoid and should be fairly safe.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#1244
Retire the dmu_snapshot_id() function which was introduced in the
initial .zfs control directory implementation. There is already
an existing dsl_dataset_snap_lookup() which does exactly what we
need, and the dmu_snapshot_id() function as implemented is racy.
https://github.com/zfsonlinux/zfs/issues/1215#issuecomment-12579879
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#1238
Added d_clear_d_op() helper function which clears some flags and the
registered dentry->d_op table. This is required because d_set_d_op()
issues a warning when the dentry operations table is already set.
For the .zfs control directory to work properly we must be able to
override the default operations table and register custom .d_automount
and .d_revalidate callbacks.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ned Bass <bass6@llnl.gov>
Closes#1230
Callers of zap_deref_leaf() must be careful to drop leaf->l_rwlock
since that function returns with the lock held on success. All other
callers drop the lock correctly but it seems fzap_cursor_move_to_key()
does not. This may block writers or cause VERIFY failures when the
lock is freed.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#1215Closeszfsonlinux/spl#143Closeszfsonlinux/spl#97
In zpl_revalidate() it's possible for the nameidata to be NULL
for kernels which still accept the parameter. In particular,
lookup_one_len() calls d_revalidate() with a NULL nameidata.
Resolve the issue by checking for a NULL nameidata in which case
just set the flags to 0.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#1226
As of Linux 2.6.37 the right way to register custom dentry
operations is to use the super block's ->s_d_op field.
For older kernels they should be registered as part of the
lookup operation.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#1223
Commit 65d56083b4 fixes the lock
inversion between spa_namespace_lock and bdev->bd_mutex but only
for the first user of spa_namespace_lock: dmu_objset_own().
Later spa_namespace_lock gets acquired by dsl_prop_get_integer()
though dsl_prop_get()->dsl_dataset_hold()->dsl_dir_open_spa()->
spa_open()->spa_open_common() without this "protection". By
moving the mutex release after this second use, even this
acquisition of the lock is "protected" by the ERESTARTSYS trick.
Signed-off-by: Massimo Maggi <me@massimo-maggi.eu>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#1220
This reverts commit 53c7411919
effectively reinstating the asynchronous xattr cleanup code.
These Linux changes were reverted because after testing
and careful contemplation I was convinced that due to the
89260a1c8851ce05ea04b23606ba438b271d890 commit they were no
longer required.
Unfortunately, the deadlock described in #1176 was a case
which wasn't considered. At mount zfs_unlinked_drain() can
occur which will unlink a list of znodes in effectively a
random order which isn't safe. The only reason it was safe
to originally revert this change was the we could guarantee
that the VFS would always prune the xattr leaves before the
parents.
Therefore, until we can cleanly resolve this deadlock for
all cases we need to keep this change in spite of the xattr
unlink performance penalty associated with it.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#1176
Issue #457
Rolling back a mounted filesystem with open file handles and
cached dentries+inodes never worked properly in ZoL. The
major issue was that Linux provides no easy mechanism for
modules to invalidate the inode cache for a file system.
Because of this it was possible that an inode from the previous
filesystem would not get properly dropped from the cache during
rolling back. Then a new inode with the same inode number would
be create and collide with the existing cached inode. Ideally
this would trigger an VERIFY() but in practice the error wasn't
handled and it would just NULL reference.
Luckily, this issue can be resolved by sprucing up the existing
Solaris zfs_rezget() functionality for the Linux VFS.
The way it works now is that when a file system is rolled back
all the cached inodes will be traversed and refetched from disk.
If a version of the cached inode exists on disk the in-core
copy will be updated accordingly. If there is no match for that
object on disk it will be unhashed from the inode cache and
marked as stale.
This will effectively make the inode unfindable for lookups
allowing the inode number to be immediately recycled. The inode
will then only be accessible from the cached dentries. Subsequent
dentry lookups which reference a stale inode will result in the
dentry being invalidated. Once invalidated the dentry will drop
its reference on the inode allowing it to be safely pruned from
the cache.
Special care is taken for negative dentries since they do not
reference any inode. These dentires will be invalidate based
on when they were added to the dentry cache. Entries added
before the last rollback will be invalidate to prevent them
from masking real files in the dataset.
Two nice side effects of this fix are:
* Removes the dependency on spl_invalidate_inodes(), it can now
be safely removed from the SPL when we choose to do so.
* zfs_znode_alloc() no longer requires a dentry to be passed.
This effectively reverts this portition of the code to its
upstream counterpart. The dentry is not instantiated more
correctly in the Linux ZPL layer.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ned Bass <bass6@llnl.gov>
Closes#795
Lookups in the snapshot control directory for an existing snapshot
fail with ENOENT if an earlier lookup failed before the snapshot was
created. This is because the earlier lookup causes a negative dentry
to be cached which is never invalidated.
The bug can be reproduced as follows (the second ls should succeed):
$ ls /tank/.zfs/snapshot/s
ls: cannot access /tank/.zfs/snapshot/s: No such file or directory
$ zfs snap tank@s
$ ls /tank/.zfs/snapshot/s
ls: cannot access /tank/.zfs/snapshot/s: No such file or directory
To remedy this, always invalidate cached dentries in the snapshot
control directory. Since these entries never exist on disk there is
no significant performance penalty for the extra lookups.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#1192
A misplaced single quote caused the umount command to fail with a
syntax error when unmounting snapshots under the .zfs/snapshot
control directory.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#1210
3189 kernel panic in ZFS test suite during hotspare_onoffline_004_neg
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Arne Jansen <sensille@gmx.net>
Approved by: Dan McDonald <danmcd@nexenta.com>
References:
illumos/illumos-gate@8f0b538d1d
changeset: 13818:e9ad0a945d45
https://www.illumos.org/issues/3189
Ported-by: Brian Behlendorf <behlendorf1@llnl.gov>
2618 arc.c mistypes in the comments
Reviewed by: Jason King <jason.brian.king@gmail.com>
Reviewed by: Josef Sipek <jeffpc@josefsipek.net>
Approved by: Richard Lowe <richlowe@richlowe.net>
References:
illumos/illumos-gate@fc98fea58e
illumos changeset: 13721:5b51a16a186f
https://www.illumos.org/issues/2618
Ported-by: Brian Behlendorf <behlendorf1@llnl.gov>
As of Linux 3.4 the UMH_WAIT_* constants were renumbered. In
particular, the meaning of "1" changed from UMH_WAIT_PROC (wait for
process to complete), to UMH_WAIT_EXEC (wait for the exec, but not the
process). A number of call sites used the number 1 instead of the
constant name, so the behavior was not as expected on kernels with this
change.
One visible consequence of this change was that processes accessing
automounted snapshots received an ELOOP error because they failed to
wait for zfs.mount to complete.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#816
This reverts commit 7afcf5b1da which
accidentally introduced a regression with the .zfs snapshot directory.
While the updated code still does correctly mount the requested
snapshot. It updates the vfsmount such that it references the
original dataset vfsmount. The result is that the snapshot itself
isn't visible.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #816
Related to 91579709fc we need to
be very careful about not overrunning the stack in kernel space.
However, in user space we're already allowing slightly larger
stacks so this stack usage optimization is not required there.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
To save valuable stack all zio's were made asynchronous when in the
tgx_sync_thread context or during pool initialization. See commit
2fac4c2 for the original patch and motivation.
Unfortuantely, the changes to dsl_pool_sync_context() made by the
feature flags broke this logic causing in __zio_execute() to dispatch
itself infinitely when called during pool initialization. This
commit refines the existing logic to specificly target only the two
cases we care about.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
3349 zpool upgrade -V bumps the on disk version number, but leaves
the in core version
Reviewed by: Adam Leventhal <ahl@delphix.com>
Reviewed by: Christopher Siden <chris.siden@delphix.com>
Reviewed by: Matt Ahrens <matthew.ahrens@delphix.com>
Reviewed by: Richard Lowe <richlowe@richlowe.net>
Approved by: Dan McDonald <danmcd@nexenta.com>
References:
illumos/illumos-gate@25345e4666https://www.illumos.org/issues/3349
Ported-by: Brian Behlendorf <behlendorf1@llnl.gov>
2762 zpool command should have better support for feature flags
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Approved by: Eric Schrock <Eric.Schrock@delphix.com>
References:
illumos/illumos-gate@57221772c3https://www.illumos.org/issues/2762
Ported-by: Brian Behlendorf <behlendorf1@llnl.gov>
3090 vdev_reopen() during reguid causes vdev to be treated as corrupt
3102 vdev_uberblock_load() and vdev_validate() may read the wrong label
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Christopher Siden <chris.siden@delphix.com>
Reviewed by: Garrett D'Amore <garrett@damore.org>
Approved by: Eric Schrock <Eric.Schrock@delphix.com>
References:
illumos/illumos-gate@dfbb943217
illumos changeset: 13777:b1e53580146d
https://www.illumos.org/issues/3090https://www.illumos.org/issues/3102
Ported-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#939
2619 asynchronous destruction of ZFS file systems
2747 SPA versioning with zfs feature flags
Reviewed by: Matt Ahrens <mahrens@delphix.com>
Reviewed by: George Wilson <gwilson@delphix.com>
Reviewed by: Richard Lowe <richlowe@richlowe.net>
Reviewed by: Dan Kruchinin <dan.kruchinin@gmail.com>
Approved by: Eric Schrock <Eric.Schrock@delphix.com>
References:
illumos/illumos-gate@53089ab7c8illumos/illumos-gate@ad135b5d64
illumos changeset: 13700:2889e2596bd6
https://www.illumos.org/issues/2619https://www.illumos.org/issues/2747
NOTE: The grub specific changes were not ported. This change
must be made to the Linux grub packages.
Ported-by: Brian Behlendorf <behlendorf1@llnl.gov>
In a debug build, certain GCC versions flag an array bounds warning in
the below code from dnode_sync.c
} else {
int i;
ASSERT(dn->dn_next_nblkptr[txgoff] < dnp->dn_nblkptr);
/* the blkptrs we are losing better be unallocated */
for (i = dn->dn_next_nblkptr[txgoff];
i < dnp->dn_nblkptr; i++)
ASSERT(BP_IS_HOLE(&dnp->dn_blkptr[i]));
This usage is in fact safe, since the ASSERT ensures the index does
not exceed to maximum possible number of block pointers. However gcc
can't determine that the assignment 'i = dn->dn_next_nblkptr[txgoff];'
falls within the array bounds so it issues a warning. To avoid this,
initialize i to zero to make gcc happy but skip the elements before
dn->dn_next_nblkptr[txgoff] in the loop body. Since a dnode contains
at most 3 block pointers this overhead should be negligible.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#950
This reverts commit 9dcb971983
which was originally introduced to debug occasional slow I/Os.
These I/Os would complete eventually but were observed to take
several 100 seconds.
The root cause of this issue was the CFQ scheduler which can,
under certain conditions, excessively delay an I/O from being
issued to the device. This issue was mitigated somewhat by
commit 84daaddedb which ensures
the I/O elevator gets changed even for DM style devices.
This change isn't in any way harmful but it does conflict with
a required change to properly account from I/O wait time.
Because Linux does not export the io_schedule_timeout() function
we must instead rely on io_schedule() via cv_wait_io().
The additional debugging information which was added to the
delay event has been intentionally left in place.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
In all but one case the spa_namespace_lock is taken before the
bdev->bd_mutex lock. But Linux __blkdev_get() function calls
fops->open() with the bdev->bd_mutex lock held and we must
somehow still safely acquire the spa_namespace_lock.
To avoid a potential lock inversion deadlock we preemptively
try to take the spa_namespace_lock(). Normally it will not
be contended and this is safe because spa_open_common() handles
the case where the caller already holds the spa_namespace_lock.
When it is contended we risk a lock inversion if we were to
block waiting for the lock. Luckily, the __blkdev_get()
function allows us to return -ERESTARTSYS which will result in
bdev->bd_mutex being dropped, reacquired, and fops->open() being
called again. This process can be repeated safely until both
locks are acquired.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Jorgen Lundman <lundman@lundman.net>
Closes#612
This reverts commit 31f2b5abdf back
to the original code until the fsync(2) performance regression
can be addressed.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
It's my understanding that the zfs_fsyncer_key TSD was added as
a performance omtimization to reduce contention on the zl_lock
from zil_commit(). This issue manifested itself as very long
(100+ms) fsync() system call times for fsync() heavy workloads.
However, under Linux I'm not seeing the same contention that
was originally described. Therefore, I'm removing this code
in order to ween ourselves off any dependence on TSD. If the
original performance issue reappears on Linux we can revisit
fixing it without resorting to TSD.
This just leaves one small ZFS TSD consumer. If it can be
cleanly removed from the code we'll be able to shed the SPL
TSD implementation entirely.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closeszfsonlinux/spl#174
The current state of udev and devicer-mapper devices makes it difficult
to construct a mapping of DM partitions and their underlying DM device.
For example, with a /dev directory with the following contents:
$ ls -d /dev/dm-*
/dev/dm-0
/dev/dm-1
/dev/dm-2
/dev/dm-3
it is not immediately apparent if these are completely separate devices,
or partitions and real devices intermixed. In contrast, SCSI devices
would appear as so:
$ ls -d /dev/sd*
/dev/sda
/dev/sda1
/dev/sdb
/dev/sdb1
Here, one can immediately determine that there are two devices (sda and
sdb), each containing a single partition. The lack of a predictable and
consistent mapping from DM devices to DM device partitions makes it
difficult for user space to process these devices the same way it does
SCSI devices.
As a result, the ZFS utilities do not partition DM devices, and instead
set the "vdev_wholedisk" label to 0 and treat them as partitions. This
has the side effect that, even if ZFS has sole ownership of the device,
the IO scheduler will not be modified because it is treated as a
partition.
This change adds an exception for DM devices in vdev_elevator_switch,
allowing the elevator to be modified even though the "vdev_wholedisk"
property is not set.
Signed-off-by: Prakash Surya <surya1@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#1149
During the original ZoL port the vdev_uses_zvols() function was
disabled until it could be properly implemented. This prevented
a zpool from use a zvol for its slog device.
This patch implements that missing functionality by adding a
zvol_is_zvol() function to zvol.c. Given the full path to a
device it will lookup the device and verify its major number
against the registered zvol major number for the system. If
they match we know the device is a zvol.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#1131
Revert the portion of commit d3aa3ea which always resulted in the
SAs being update when an mmap()'ed file was closed. That change
accidentally resulted in unexpected ctime updates which upset tools
like git. That was always a horrible hack and I'm happy it will
never make it in to a tagged release.
The right fix is something I initially resisted doing because I
was worried about the additional overhead. However, in hindsight
the overhead isn't as bad as I feared.
This patch implemented the sops->dirty_inode() callback which is
unsurprisingly called when an inode is dirtied. We leverage this
callback to keep the znode SAs strictly in sync with the inode.
However, for now we're going to go slowly to avoid introducing
any new unexpected issues by only updating the atime, mtime, and
ctime. This will cover the callpath of most concern to us.
->filemap_page_mkwrite->file_update_time->update_time->
mark_inode_dirty_sync->__mark_inode_dirty->dirty_inode
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#764Closes#1140
Ensure that the path member pointers are associated with the
newly-mounted snapshot when zpl_snapdir_automount() returns. Otherwise
the follow_automount() function may be called repeatedly, leading to an
incorrect ELOOP error return. This problem was observed as a 'Too many
levels of symbolic links' error from user-space commands accessing an
unmounted snapshot in the .zfs/snapshot directory.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#816
