Fix rollback of mounted filesystem regression

The Illumos #3875 patch reverted a part of ZoL's 7b3e34b which added
special-case error handling for zfs_rezget().  The error handling dealt
with the case in which an all-ones object number ended up being passed
to dnode_hold() and causing an EINVAL to be returned from zfs_rezget().

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #1859
Closes #1861
Some nvlist allocations in hold processing need to use KM_PUSHPAGE.

Commit 95fd54a1c5b93bb2aa3e7dffc28c784b1e21a8bb restructured the
hold/release processing and moved some of the work into the sync task.
A number of nvlist allocations now need to use KM_PUSHPAGE.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #1852
Closes #1855
Reduce stack for traverse_visitbp() recursion

During pool import stack overflows may still occur due to the
potentially deep recursion of traverse_visitbp().  This is most
likely to occur when additional layers are added to the block
device stack such as DM multipath.  To minimize the stack usage
for this call path the following changes were made:

1) Added the keywork 'noinline' to the vdev_*_map_alloc() functions
   to prevent them from being inlined by gcc.  This reduced the
   stack usage of vdev_raidz_io_start() from 208 to 128 bytes, and
   vdev_mirror_io_start() from 144 to 128 bytes.

2) The 'saved_poolname' charater array in zfsdev_ioctl() was moved
   from the stack to the heap.  This reduced the stack usage of
   zfsdev_ioctl() from 368 to 112 bytes.

3) The major saving came from slimming down traverse_visitbp() from
   from 224 to 144 bytes.  Since this function is called recursively
   the 80 bytes saved per invokation adds up.  The following changes
   were made:

  a) The 'hard' local variable was replaced by a TD_HARD() macro.

  b) The 'pd' local variable was replaced by 'td->td_pfd' references.

  c) The zbookmark_t was moved to the heap.  This does cost us an
     additional memory allocation per recursion by that cost should
     still be minimal.  The cost could be further reduced by adding
     a dedicated zbookmark_t slab cache.

  d) The variable declarations in 'if (BP_GET_LEVEL()) { }' were
     restructured to use the minimum amount of stack.  This includes
     removing the 'cbp' local variable.

Overall for the offending use case roughly 1584 of total stack space
has been saved.  This is enough to avoid overflowing the stack on
stock kernels with 8k stacks.  See #1778 for additional details.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ned Bass <bass6@llnl.gov>
Closes #1778
Fixes (extends) support for selinux xattrs to more inode types

Properly initialize SELinux xattrs for all inode types.  The
initial implementation accidentally only did this for files.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #1832
Tighten zfs dependency on zfs-kmod

Make zfs depend on the same version of zfs-kmod, rather than on same or
better. When yum repository contains a number of versions the dependency
resolution breaks on trying to install non-latest version.

Signed-off-by: Cyril Plisko <cyril.plisko@mountall.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #1677
Remove the slog restriction on bootfs pools

Under Linux this restriction does not apply because we have access
to all the required devices.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #1631
Fix typos in commit b83e3e48c9b183a80dd00eb6c7431a1cbc7d89c9

There's a missing semicolon and equals sign in the first hunk of this
commit in config/kernel-bdi.m4. This results in the test always
failing. The effects were noticed when rrdtool, a tool which modifies
files by mmap() and msync(), would have data never get saved to disk
in spite of the files working while the mounted filesystem remains
mounted.

Signed-off-by: DHE <git@dehacked.net>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Richard Yao <ryao@gentoo.org>
Closes #1889
Illumos #4322

4322 ZFS deadlock on dp_config_rwlock
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Ilya Usvyatsky <ilya.usvyatsky@nexenta.com>
Approved by: Dan McDonald <danmcd@nexenta.com>

References:
  https://www.illumos.org/issues/4322
  illumos/illumos-gate@c50d56f667f119d78fa3d94d6bef2c298ba556f6

Ported by: Chris Dunlop <chris@onthe.net.au>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #1886
Add missing libzfs_core to Makefiles

On some platforms symbols provided by libzfs_core and used by
libzfs were not available to the linker.  To avoid this issue
libzfs_core has been added to the list of required libraries
when building utilities which depend on libzfs.  This should
have been handled properly by libtool and it's still not
entirely clear why it wasn't on all platforms.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #1841
Document ZFS module parameters.

This is a first draft of a zfs-module-parameters(5) man page. I have
just extracted the parameter name and its description with modinfo,
then checked the source what type it is and its default value.

This will need more work, preferably someone that actually know these
values and what to use them for.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #1856
Add I/O Read/Write Accounting

Because ZFS bypasses the page cache we don't inherit per-task I/O
accounting for free.  However, the Linux kernel does provide helper
functions allow us to perform our own accounting.  These are most
commonly used for direct IO which also bypasses the page cache, but
they can be used for the common read/write call paths as well.

Signed-off-by: Pavel Snajdr <snajpa@snajpa.net>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #313
Closes #1275
Illumos #2583

2583 Add -p (parsable) option to zfs list

References:
  https://www.illumos.org/issues/2583
  illumos/illumos-gate@43d68d68c1ce08fb35026bebfb141af422e7082e

Ported-by: Gregor Kopka <gregor@kopka.net>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes: #937
Change zfs-dkms requirement

Version 2.2.0.3-20 of dkms in the EPEL/Fedora repositories added the
necessary patches to support ZoL,  Therefore, the zfs-dkms requirement
on dkms is set to match that version or higher.  This allows us to
drop the custom dkms build in the ZoL EPEL/Fedora repositories.

References:
  https://bugzilla.redhat.com/show_bug.cgi?id=1023598

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #1873
Only commit the ZIL once in zpl_writepages() (msync() case).

Currently, using msync() results in the following code path:

    sys_msync -> zpl_fsync -> filemap_write_and_wait_range -> zpl_writepages -> write_cache_pages -> zpl_putpage

In such a code path, zil_commit() is called as part of zpl_putpage().
This means that for each page, the write is handed to the DMU, the ZIL
is committed, and only then do we move on to the next page. As one might
imagine, this results in atrocious performance where there is a large
number of pages to write: instead of committing a batch of N writes,
we do N commits containing one page each. In some extreme cases this
can result in msync() being ~700 times slower than it should be, as well
as very inefficient use of ZIL resources.

This patch fixes this issue by making sure that the requested writes
are batched and then committed only once. Unfortunately, the
implementation is somewhat non-trivial because there is no way to run
write_cache_pages in SYNC mode (so that we get all pages) without
making it wait on the writeback tag for each page.

The solution implemented here is composed of two parts:

 - I added a new callback system to the ZIL, which allows the caller to
   be notified when its ITX gets written to stable storage. One nice
   thing is that the callback is called not only in zil_commit() but
   in zil_sync() as well, which means that the caller doesn't have to
   care whether the write ended up in the ZIL or the DMU: it will get
   notified as soon as it's safe, period. This is an improvement over
   dmu_tx_callback_register() that was used previously, which only
   supports DMU writes. The rationale for this change is to allow
   zpl_putpage() to be notified when a ZIL commit is completed without
   having to block on zil_commit() itself.

 - zpl_writepages() now calls write_cache_pages in non-SYNC mode, which
   will prevent (1) write_cache_pages from blocking, and (2) zpl_putpage
   from issuing ZIL commits. zpl_writepages() will issue the commit
   itself instead of relying on zpl_putpage() to do it, thus nicely
   batching the writes. Note, however, that we still have to call
   write_cache_pages() again in SYNC mode because there is an edge case
   documented in the implementation of write_cache_pages() whereas it
   will not give us all dirty pages when running in non-SYNC mode. Thus
   we need to run it at least once in SYNC mode to make sure we honor
   persistency guarantees. This only happens when the pages are
   modified at the same time msync() is running, which should be rare.
   In most cases there won't be any additional pages and this second
   call will do nothing.

Note that this change also fixes a bug related to #907 whereas calling
msync() on pages that were already handed over to the DMU in a previous
writepages() call would make msync() block until the next TXG sync
instead of returning as soon as the ZIL commit is complete. The new
callback system fixes that problem.

Signed-off-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #1849
Closes #907
Some nvlist allocations in hold processing need to use KM_PUSHPAGE.

This should hopefully catch the rest of the allocations in the
user hold/release processing that were missed by commit
65c67ea86e9f112177f1ad32de8e780f10798a64.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #1852
Closes #1855
Drive database update

Added:

Adata S396 (obtained from drive_id)
Apple MacBookAir3,1 SSD (obtained from drive_id)
Apple MacBookPro10,1 SSD (obtained from drive_id)
Intel 510 (obtained from drive_id)
Intel 710 (obtained from drive_id)
Intel DC S3500 (obtained from drive_id)
Netapp LUN (obtained from illumos user's sd.conf)
OCZ Agility 3 (obtained from drive_id)
OCZ Vertex (obtained from drive_id)
Samsung PM800 (obtained from drive_id)
Sandisk U100 (obtained from drive_id)
Sun Comstar (obtained from illumos user's sd.conf)

Notes:

1. The entries for the Intel DC S3500 were extrapolated from the 800GB
model's entry, which is "ATA     INTEL SSDSC2BB80".

2. The entires for the Intel 710 were extrapolated from the 120GG
model's entry, which is "ATA     INTEL SSDSA2BZ12".

3. The entires for the Intel 510 were extrapolated from the 250GB
model's entry, which is "ATA     INTEL SSDSC2MH25".

4. The entires for the Apple MacBookPro10,1 SSD were extrapolated from
the 512GB model's entry, which is "ATA     APPLE SSD SM512E". Google
searches suggest that this is a rebadged Samsung 830.

5. The entires for the Apple MacBookAir3,1 SSD were extrapolated from
the 128GB model's entry, which is "ATA     APPLE SSD TS128C". Google
searches suggest that this is a rebadged Kingston SSDNow V+ 100 (based
on Toshiba).

6. Sun Comstar is an iSCSI Target, so we cannot tell what the correct
sector size is through this method. We list it only for reference
purposes, but it is commented out. Similarly, it is not clear what the
right thing to do for Netapp is, so we comment it out.

Signed-off-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #1907
Remove incorrect ASSERT in zfs_sb_teardown()

As part of zfs_sb_teardown() there is an assertion that all inodes
which are part of the zsb->z_all_znodes list have at least one
reference on them.  This is always true for the standard unmount
case but there are two other cases where it is not strictly true.

* zfs_ioc_rollback() - This is the most common case and it results
  from the fact that we aren't unmounting the filesystem.  During a
  normal unmount the MS_ACTIVE flag will be cleared on the super block
  causing iput_final() to evict the inode when its reference count
  drops to zero.  However, during a rollback MS_ACTIVE remains set
  since we're rolling back a live filesystem and need to preserve the
  existing super block.  This allows inodes with a zero reference count
  to stay in the cache thereby violating the assertion.

* destroy_inode() / zfs_sb_teardown() - There exists a small race
  between dropping the last reference on an inode and removing it from
  the zsb->z_all_znodes list.  This is unlikely to occur but could also
  trigger the assertion which is incorrect.  The inode may safely have
  a zero reference count in this case.

Since allowing a zero reference count on the inode is expected and
safe for both of these cases the simplest thing to do is remove the
ASSERT.  This code is only enabled for default builds so removing
this entirely is a very safe change.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Chris Dunlop <chris@onthe.net.au>
Signed-off-by: Tim Chase <tim@chase2k.com>
Closes #1417
Closes #1536
Properly ignore bdi_setup_and_register return value

This broke compilation against Linux 3.13 and GCC 4.7.3.

Signed-off-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #1906
Illumos #4347 ZPL can use dmu_tx_assign(TXG_WAIT)

Fix a lock contention issue by allowing threads not holding
ZPL locks to block when waiting to assign a transaction.

Porting Notes:

zfs_putpage() still uses TXG_NOWAIT, unlike the upstream version.  This
case may be a contention point just like zfs_write(), however it is not
safe to block here since it may be called during memory reclaim.

Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Adam Leventhal <ahl@delphix.com>
Reviewed by: Dan McDonald <danmcd@nexenta.com>
Reviewed by: Boris Protopopov <boris.protopopov@nexenta.com>
Approved by: Dan McDonald <danmcd@nexenta.com>

References:
  https://www.illumos.org/issues/4347
  illumos/illumos-gate@e722410c49fe67cbf0f639cbcc288bd6cbcf7dd1

Ported-by: Ned Bass <bass6@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Illumos #4045 write throttle & i/o scheduler performance work

4045 zfs write throttle & i/o scheduler performance work

1. The ZFS i/o scheduler (vdev_queue.c) now divides i/os into 5 classes: sync
read, sync write, async read, async write, and scrub/resilver.  The scheduler
issues a number of concurrent i/os from each class to the device.  Once a class
has been selected, an i/o is selected from this class using either an elevator
algorithem (async, scrub classes) or FIFO (sync classes).  The number of
concurrent async write i/os is tuned dynamically based on i/o load, to achieve
good sync i/o latency when there is not a high load of writes, and good write
throughput when there is.  See the block comment in vdev_queue.c (reproduced
below) for more details.

2. The write throttle (dsl_pool_tempreserve_space() and
txg_constrain_throughput()) is rewritten to produce much more consistent delays
when under constant load.  The new write throttle is based on the amount of
dirty data, rather than guesses about future performance of the system.  When
there is a lot of dirty data, each transaction (e.g. write() syscall) will be
delayed by the same small amount.  This eliminates the "brick wall of wait"
that the old write throttle could hit, causing all transactions to wait several
seconds until the next txg opens.  One of the keys to the new write throttle is
decrementing the amount of dirty data as i/o completes, rather than at the end
of spa_sync().  Note that the write throttle is only applied once the i/o
scheduler is issuing the maximum number of outstanding async writes.  See the
block comments in dsl_pool.c and above dmu_tx_delay() (reproduced below) for
more details.

This diff has several other effects, including:

 * the commonly-tuned global variable zfs_vdev_max_pending has been removed;
use per-class zfs_vdev_*_max_active values or zfs_vdev_max_active instead.

 * the size of each txg (meaning the amount of dirty data written, and thus the
time it takes to write out) is now controlled differently.  There is no longer
an explicit time goal; the primary determinant is amount of dirty data.
Systems that are under light or medium load will now often see that a txg is
always syncing, but the impact to performance (e.g. read latency) is minimal.
Tune zfs_dirty_data_max and zfs_dirty_data_sync to control this.

 * zio_taskq_batch_pct = 75 -- Only use 75% of all CPUs for compression,
checksum, etc.  This improves latency by not allowing these CPU-intensive tasks
to consume all CPU (on machines with at least 4 CPU's; the percentage is
rounded up).

--matt

APPENDIX: problems with the current i/o scheduler

The current ZFS i/o scheduler (vdev_queue.c) is deadline based.  The problem
with this is that if there are always i/os pending, then certain classes of
i/os can see very long delays.

For example, if there are always synchronous reads outstanding, then no async
writes will be serviced until they become "past due".  One symptom of this
situation is that each pass of the txg sync takes at least several seconds
(typically 3 seconds).

If many i/os become "past due" (their deadline is in the past), then we must
service all of these overdue i/os before any new i/os.  This happens when we
enqueue a batch of async writes for the txg sync, with deadlines 2.5 seconds in
the future.  If we can't complete all the i/os in 2.5 seconds (e.g. because
there were always reads pending), then these i/os will become past due.  Now we
must service all the "async" writes (which could be hundreds of megabytes)
before we service any reads, introducing considerable latency to synchronous
i/os (reads or ZIL writes).

Notes on porting to ZFS on Linux:

- zio_t gained new members io_physdone and io_phys_children.  Because
  object caches in the Linux port call the constructor only once at
  allocation time, objects may contain residual data when retrieved
  from the cache. Therefore zio_create() was updated to zero out the two
  new fields.

- vdev_mirror_pending() relied on the depth of the per-vdev pending queue
  (vq->vq_pending_tree) to select the least-busy leaf vdev to read from.
  This tree has been replaced by vq->vq_active_tree which is now used
  for the same purpose.

- vdev_queue_init() used the value of zfs_vdev_max_pending to determine
  the number of vdev I/O buffers to pre-allocate.  That global no longer
  exists, so we instead use the sum of the *_max_active values for each of
  the five I/O classes described above.

- The Illumos implementation of dmu_tx_delay() delays a transaction by
  sleeping in condition variable embedded in the thread
  (curthread->t_delay_cv).  We do not have an equivalent CV to use in
  Linux, so this change replaced the delay logic with a wrapper called
  zfs_sleep_until(). This wrapper could be adopted upstream and in other
  downstream ports to abstract away operating system-specific delay logic.

- These tunables are added as module parameters, and descriptions added
  to the zfs-module-parameters.5 man page.

  spa_asize_inflation
  zfs_deadman_synctime_ms
  zfs_vdev_max_active
  zfs_vdev_async_write_active_min_dirty_percent
  zfs_vdev_async_write_active_max_dirty_percent
  zfs_vdev_async_read_max_active
  zfs_vdev_async_read_min_active
  zfs_vdev_async_write_max_active
  zfs_vdev_async_write_min_active
  zfs_vdev_scrub_max_active
  zfs_vdev_scrub_min_active
  zfs_vdev_sync_read_max_active
  zfs_vdev_sync_read_min_active
  zfs_vdev_sync_write_max_active
  zfs_vdev_sync_write_min_active
  zfs_dirty_data_max_percent
  zfs_delay_min_dirty_percent
  zfs_dirty_data_max_max_percent
  zfs_dirty_data_max
  zfs_dirty_data_max_max
  zfs_dirty_data_sync
  zfs_delay_scale

  The latter four have type unsigned long, whereas they are uint64_t in
  Illumos.  This accommodates Linux's module_param() supported types, but
  means they may overflow on 32-bit architectures.

  The values zfs_dirty_data_max and zfs_dirty_data_max_max are the most
  likely to overflow on 32-bit systems, since they express physical RAM
  sizes in bytes.  In fact, Illumos initializes zfs_dirty_data_max_max to
  2^32 which does overflow. To resolve that, this port instead initializes
  it in arc_init() to 25% of physical RAM, and adds the tunable
  zfs_dirty_data_max_max_percent to override that percentage.  While this
  solution doesn't completely avoid the overflow issue, it should be a
  reasonable default for most systems, and the minority of affected
  systems can work around the issue by overriding the defaults.

- Fixed reversed logic in comment above zfs_delay_scale declaration.

- Clarified comments in vdev_queue.c regarding when per-queue minimums take
  effect.

- Replaced dmu_tx_write_limit in the dmu_tx kstat file
  with dmu_tx_dirty_delay and dmu_tx_dirty_over_max.  The first counts
  how many times a transaction has been delayed because the pool dirty
  data has exceeded zfs_delay_min_dirty_percent.  The latter counts how
  many times the pool dirty data has exceeded zfs_dirty_data_max (which
  we expect to never happen).

- The original patch would have regressed the bug fixed in
  zfsonlinux/zfs@c418410, which prevented users from setting the
  zfs_vdev_aggregation_limit tuning larger than SPA_MAXBLOCKSIZE.
  A similar fix is added to vdev_queue_aggregate().

- In vdev_queue_io_to_issue(), dynamically allocate 'zio_t search' on the
  heap instead of the stack.  In Linux we can't afford such large
  structures on the stack.

Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Adam Leventhal <ahl@delphix.com>
Reviewed by: Christopher Siden <christopher.siden@delphix.com>
Reviewed by: Ned Bass <bass6@llnl.gov>
Reviewed by: Brendan Gregg <brendan.gregg@joyent.com>
Approved by: Robert Mustacchi <rm@joyent.com>

References:
  http://www.illumos.org/issues/4045
  illumos/illumos-gate@69962b5647e4a8b9b14998733b765925381b727e

Ported-by: Ned Bass <bass6@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #1913