Commit Graph

748 Commits

Author SHA1 Message Date
Martin Matuska
b3b6851c78 Add missing init functions
Reduce diff to illumos
2013-03-06 11:33:25 +00:00
Xin LI
2f79ac7f21 Diff reduction with Illumos 2013-03-06 01:21:56 +00:00
Xin LI
227d24fc59 Use adx2 instead of adx in the second vsprintf, this fixes a
panic.
2013-03-05 22:58:53 +00:00
Martin Matuska
dce1a726f2 WiP merge of libzfs_core (MFV r238590, r238592)
not yet working, ioctl handling needs to be changed
2013-03-05 08:09:53 +00:00
Rui Paulo
e0dffa2de2 Remove the extra parenthesis from the cv_init() macro. They are not
necessary because we already use parenthesis in zfs_cv_init().

This fixes a long standing bug where there would be an extra ")" at the
end of the string. This extra parenthesis would show up in the WCHAN of
the process (top, stty status, etc.).
2013-03-03 06:42:36 +00:00
Pawel Jakub Dawidek
2609222ab4 Merge Capsicum overhaul:
- Capability is no longer separate descriptor type. Now every descriptor
  has set of its own capability rights.

- The cap_new(2) system call is left, but it is no longer documented and
  should not be used in new code.

- The new syscall cap_rights_limit(2) should be used instead of
  cap_new(2), which limits capability rights of the given descriptor
  without creating a new one.

- The cap_getrights(2) syscall is renamed to cap_rights_get(2).

- If CAP_IOCTL capability right is present we can further reduce allowed
  ioctls list with the new cap_ioctls_limit(2) syscall. List of allowed
  ioctls can be retrived with cap_ioctls_get(2) syscall.

- If CAP_FCNTL capability right is present we can further reduce fcntls
  that can be used with the new cap_fcntls_limit(2) syscall and retrive
  them with cap_fcntls_get(2).

- To support ioctl and fcntl white-listing the filedesc structure was
  heavly modified.

- The audit subsystem, kdump and procstat tools were updated to
  recognize new syscalls.

- Capability rights were revised and eventhough I tried hard to provide
  backward API and ABI compatibility there are some incompatible changes
  that are described in detail below:

	CAP_CREATE old behaviour:
	- Allow for openat(2)+O_CREAT.
	- Allow for linkat(2).
	- Allow for symlinkat(2).
	CAP_CREATE new behaviour:
	- Allow for openat(2)+O_CREAT.

	Added CAP_LINKAT:
	- Allow for linkat(2). ABI: Reuses CAP_RMDIR bit.
	- Allow to be target for renameat(2).

	Added CAP_SYMLINKAT:
	- Allow for symlinkat(2).

	Removed CAP_DELETE. Old behaviour:
	- Allow for unlinkat(2) when removing non-directory object.
	- Allow to be source for renameat(2).

	Removed CAP_RMDIR. Old behaviour:
	- Allow for unlinkat(2) when removing directory.

	Added CAP_RENAMEAT:
	- Required for source directory for the renameat(2) syscall.

	Added CAP_UNLINKAT (effectively it replaces CAP_DELETE and CAP_RMDIR):
	- Allow for unlinkat(2) on any object.
	- Required if target of renameat(2) exists and will be removed by this
	  call.

	Removed CAP_MAPEXEC.

	CAP_MMAP old behaviour:
	- Allow for mmap(2) with any combination of PROT_NONE, PROT_READ and
	  PROT_WRITE.
	CAP_MMAP new behaviour:
	- Allow for mmap(2)+PROT_NONE.

	Added CAP_MMAP_R:
	- Allow for mmap(PROT_READ).
	Added CAP_MMAP_W:
	- Allow for mmap(PROT_WRITE).
	Added CAP_MMAP_X:
	- Allow for mmap(PROT_EXEC).
	Added CAP_MMAP_RW:
	- Allow for mmap(PROT_READ | PROT_WRITE).
	Added CAP_MMAP_RX:
	- Allow for mmap(PROT_READ | PROT_EXEC).
	Added CAP_MMAP_WX:
	- Allow for mmap(PROT_WRITE | PROT_EXEC).
	Added CAP_MMAP_RWX:
	- Allow for mmap(PROT_READ | PROT_WRITE | PROT_EXEC).

	Renamed CAP_MKDIR to CAP_MKDIRAT.
	Renamed CAP_MKFIFO to CAP_MKFIFOAT.
	Renamed CAP_MKNODE to CAP_MKNODEAT.

	CAP_READ old behaviour:
	- Allow pread(2).
	- Disallow read(2), readv(2) (if there is no CAP_SEEK).
	CAP_READ new behaviour:
	- Allow read(2), readv(2).
	- Disallow pread(2) (CAP_SEEK was also required).

	CAP_WRITE old behaviour:
	- Allow pwrite(2).
	- Disallow write(2), writev(2) (if there is no CAP_SEEK).
	CAP_WRITE new behaviour:
	- Allow write(2), writev(2).
	- Disallow pwrite(2) (CAP_SEEK was also required).

	Added convinient defines:

	#define	CAP_PREAD		(CAP_SEEK | CAP_READ)
	#define	CAP_PWRITE		(CAP_SEEK | CAP_WRITE)
	#define	CAP_MMAP_R		(CAP_MMAP | CAP_SEEK | CAP_READ)
	#define	CAP_MMAP_W		(CAP_MMAP | CAP_SEEK | CAP_WRITE)
	#define	CAP_MMAP_X		(CAP_MMAP | CAP_SEEK | 0x0000000000000008ULL)
	#define	CAP_MMAP_RW		(CAP_MMAP_R | CAP_MMAP_W)
	#define	CAP_MMAP_RX		(CAP_MMAP_R | CAP_MMAP_X)
	#define	CAP_MMAP_WX		(CAP_MMAP_W | CAP_MMAP_X)
	#define	CAP_MMAP_RWX		(CAP_MMAP_R | CAP_MMAP_W | CAP_MMAP_X)
	#define	CAP_RECV		CAP_READ
	#define	CAP_SEND		CAP_WRITE

	#define	CAP_SOCK_CLIENT \
		(CAP_CONNECT | CAP_GETPEERNAME | CAP_GETSOCKNAME | CAP_GETSOCKOPT | \
		 CAP_PEELOFF | CAP_RECV | CAP_SEND | CAP_SETSOCKOPT | CAP_SHUTDOWN)
	#define	CAP_SOCK_SERVER \
		(CAP_ACCEPT | CAP_BIND | CAP_GETPEERNAME | CAP_GETSOCKNAME | \
		 CAP_GETSOCKOPT | CAP_LISTEN | CAP_PEELOFF | CAP_RECV | CAP_SEND | \
		 CAP_SETSOCKOPT | CAP_SHUTDOWN)

	Added defines for backward API compatibility:

	#define	CAP_MAPEXEC		CAP_MMAP_X
	#define	CAP_DELETE		CAP_UNLINKAT
	#define	CAP_MKDIR		CAP_MKDIRAT
	#define	CAP_RMDIR		CAP_UNLINKAT
	#define	CAP_MKFIFO		CAP_MKFIFOAT
	#define	CAP_MKNOD		CAP_MKNODAT
	#define	CAP_SOCK_ALL		(CAP_SOCK_CLIENT | CAP_SOCK_SERVER)

Sponsored by:	The FreeBSD Foundation
Reviewed by:	Christoph Mallon <christoph.mallon@gmx.de>
Many aspects discussed with:	rwatson, benl, jonathan
ABI compatibility discussed with:	kib
2013-03-02 00:53:12 +00:00
Xin LI
5c737b11df MFV r247575:
Import a fix tighten assertion on SPA versions from vendor (Illumos).

Illumos ZFS issue:

  3543 Feature flags causes assertion in spa.c to miss certain cases

MFC after:	2 weeks
2013-03-01 22:20:13 +00:00
Martin Matuska
4abd59512a MFV r247316:
Merge new read-only zfs properties from vendor (illumos)

Illumos ZFS issues:
  3588 provide zfs properties for logical (uncompressed) space used and
       referenced

References:
  https://www.illumos.org/issues/3588

MFC after:	2 weeks
2013-03-01 21:58:51 +00:00
Martin Matuska
bb508e7732 Fix the zfs_ioctl compat layer to support zfs_cmd size change introduced
in r247265 (ZFS deadman thread). Both new utilities now support the old
kernel and new kernel properly detects old utilities.

For future backwards compatibility, the vfs.zfs.version.ioctl read-only
sysctl has been introduced. With this sysctl zfs utilities will be able
to detect the ioctl interface version of the currently loaded zfs module.

As a side effect, the zfs utilities between r247265 and this revision don't
support the old kernel module. If you are using HEAD newer or equal than
r247265, install the new kernel module (or whole kernel) first.

MFC after:	10 days
2013-03-01 09:42:58 +00:00
Martin Matuska
24245e76ea MFV 247176, 247178, 247315:
Import metaslab_sync() speedup from vendor (illumos).

Illumos ZFS issues:
  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)
  3578 transferring the freed map to the defer map should be constant time
  3579 ztest trips assertion in metaslab_weight()

References:
  https://www.illumos.org/issues/3552
  https://www.illumos.org/issues/3564
  https://www.illumos.org/issues/3578
  https://www.illumos.org/issues/3579

MFC after:	2 weeks
2013-02-27 14:45:23 +00:00
Martin Matuska
e4428d63a8 Be more verbose on ZFS deadman I/O panic
Patch suggested upstream.

Suggested by:	Olivier Cinquin
MFC after:	12 days
2013-02-26 20:41:27 +00:00
Martin Matuska
e70664bafc MFV v242732:
Merge the ZFS I/O deadman thread from vendor (illumos).
This feature panics the system on hanging ZFS I/O, helps debugging
and resumes failed service.

The panic behavior can be controlled with the loader-only tunables:
vfs.zfs.deadman_enabled (enable or disable panic on stalled ZFS I/O)
vfs.zfs.deadman_synctime (expiration time for stalled ZFS I/O)

By default, ZFS I/O deadman is enabled by default on amd64 and i386
excluding virtual guest machines.

Illumos ZFS issues:
  3246 ZFS I/O deadman thread

References:
  https://www.illumos.org/issues/3246

MFC after:	2 weeks
2013-02-25 12:33:31 +00:00
Martin Matuska
781c0f87d3 MFV r246653:
Import vendor change to avoid "unitialized variable" warnings.

Illumos ZFS issues:
  3522 zfs module should not allow uninitialized variables

References:
  https://www.illumos.org/issues/3522
2013-02-23 11:21:05 +00:00
Justin T. Gibbs
6a8f90edf5 Avoid panic when tearing down the DTrace pid provider for a
process that has crashed.

sys/cddl/contrib/opensolaris/uts/common/dtrace/fasttrap.c:
	In fasttrap_pid_disable(), we cannot PHOLD the proc
	structure for a process that no longer exists, but
	we still have other, fasttrap specific, state that
	must be cleaned up for probes that existed in the
	dead process.  Instead of returning early if the
	process related to our probes isn't found,
	conditionalize the locking and carry on with a NULL
	proc pointer.  The rest of the fasttrap code already
	understands that a NULL proc is possible and does
	the right things in this case.

Sponsored by:	Spectra Logic Corporation
Reviewed by:	rpaulo, gnn
MFC after:	1 week
2013-02-20 17:55:17 +00:00
Xin LI
e469d5a70f Eliminate real_LZ4_uncompress. It's unused and does not perform sufficient
check against input stream (i.e. it could read beyond specified input
buffer).
2013-02-14 21:02:18 +00:00
Martin Matuska
7c695febc9 Change vfs.zfs.write_to_degraded from CTLFLAG_RW to CTLFLAG_RWTUN
Suggested by:	pjd
2013-02-13 23:11:25 +00:00
Xin LI
314caba11c Restore De Bruijn algorithm for sparc64 where the compiler rely on a
library function for __builtin_c?z.

Tested by:	Michael Moll <kvedulv kvedulv de>
2013-02-13 17:30:54 +00:00
Martin Matuska
6a33bbc041 Merge zfs_ioctl.c code that should have been merged together with ZFS v28.
Fixes several problems if working with read-only pools.

Changed code originaly introduced in onnv-gate 13061:bda0decf867b
Contains changes up to illumos-gate 13700:4bc0783f6064

PR:		kern/175897
Suggested by:	avg

MFC after:	2 weeks
2013-02-11 21:10:55 +00:00
Martin Matuska
9689178c3f MFV r246633:
Import vendor bugfixes regarding SA rounding, header size and layout.
This was already partially fixed by avg.

Illumos ZFS issues:
  3512 rounding discrepancy in sa_find_sizes()
  3513 mismatch between SA header size and layout

References:
  https://www.illumos.org/issues/3512
  https://www.illumos.org/issues/3513

MFC after:	2 weeks
2013-02-11 14:29:38 +00:00
Martin Matuska
bb03847418 MFV r246394:
Add tunable to allow block allocation on degraded vdevs.

Illumos ZFS issues:
  3507 Tunable to allow block allocation even on degraded vdevs

References:
  https://www.illumos.org/issues/3507

MFC after:	2 weeks
2013-02-11 13:59:57 +00:00
Martin Matuska
ff20578569 MFV r246392:
Import vendor ZFS bugfix fixing a possible deadlock in arc_read().

Illumos ZFS issues:
  3498 panic in arc_read(): !refcount_is_zero(&pbuf->b_hdr->b_refcnt)

References:
  https://www.illumos.org/issues/3498

MFC after:	2 weeks
2013-02-11 12:42:11 +00:00
Martin Matuska
8a2dc7faae MFV r246390:
Import minor type change in refcount.h header from vendor (illumos).

MFC after:	2 weeks
2013-02-11 07:48:57 +00:00
Martin Matuska
fd9778c236 MFV r246388:
Import vendor bugfixes

Illumos ZFS issues:
  3422 zpool create/syseventd race yield non-importable pool
  3425 first write to a new zvol can fail with EFBIG

References:
  https://www.illumos.org/issues/3422
  https://www.illumos.org/issues/3425

MFC after:	2 weeks
2013-02-10 19:32:55 +00:00
Xin LI
ef17620fc8 MFV r245512:
* Illumos zfs issue #3035 [1] LZ4 compression support in ZFS.

LZ4 is a new high-speed BSD-licensed compression algorithm created
by Yann Collet that delivers very high compression and decompression
performance compared to lzjb (>50% faster on compression, >80% faster
on decompression and around 3x faster on compression of incompressible
data), while giving better compression ratio [1].

This version of LZ4 corresponds to upstream's [2] revision 85.

Please note that for obvious reasons this is not backward read
compatible.  This means once a pool have LZ4 compressed data, these
data can no longer be read by older ZFS implementations.

Local changes:

 - On-stack hash table disabled and using kernel slab allocator
   instead, at this time.  This requires larger kernel thread stack
   for zio workers.  This may change in the future should we adjusted
   the zio workers' thread stack size.
 - likely and unlikely will be undefined if they are already defined,
   this is required for i386 XEN build.
 - Removed De Bruijn sequence based __builtin_ctz family of builtins
   in favor of the latter.  Both GCC and clang supports these builtins.
 - Changed the way the LZ4 code detects endianness.
 - Manual pages modifications to mention the feature based on Illumos
   counterpart.
 - Boot loader changes to make it support LZ4 decompression.

[1] https://www.illumos.org/issues/3035
[2] http://code.google.com/p/lz4/source/list

Obtained from:	Illumos (13921:9d721847e469)
Tested on:	FreeBSD/amd64
MFC after:	1 month
2013-02-09 06:39:28 +00:00
Sergey Kandaurov
3c56b4f165 Fix warning: comparison of unsigned expression < 0 is always false.
Reported by:	clang
2013-02-08 09:54:53 +00:00
Andriy Gapon
0dcab786b8 zfs_vget, zfs_fhtovp: properly handle the z_shares_dir object
A special gfs vnode corresponds to that object.
A regular zfs vnode must not be returned.

This should be upstreamed.

Reported by:	pluknet
Submitted by:	rmacklem
Tested by:	pluknet
MFC after:	10 days
2013-02-08 07:49:54 +00:00
Andriy Gapon
e2bb19dce5 zfs: update comments about zfid_long_t to match the FreeBSD definitions
MFC after:	1 week
2013-02-08 07:44:15 +00:00
Andriy Gapon
c7d346f269 zfs: fix, improve and re-organize page_lookup and page_unlock
Now they are split into two pairs: page_hold/page_unhold for mappedread
and page_busy/page_unbusy for update_pages.

For mappedread we simply hold a page that is to be used as a source if it
is resident and valid (and not busy).  This is sufficient since we are
only doing page -> user buffer copying.  There is no page <-> backing
storage I/O involved.

update_pages is now better split to properly handle the putpages case
(page -> arc) and the regular write case (arc -> page).

For the latter we use complete protocol of marking an object with
paging-in-progress and marking a page with io_start (busy count).
Also, in this case we remove the write bit from all page mappings and
clear dirty bits of the pages, the former is needed to ensure that the
latter does the right thing.
Additionally we update a page if it is cached instead of just freeing it
as was done before.  This needs to be verified.

A minor detail: ZFS-backed pages should always be either fully valid
or fully invalid.  Assert this and use simpler API that does not deal
with sub-page blocks.

Reviewed by:	kib
MFC after:	26 days
2013-02-03 18:42:20 +00:00
Justin Hibbits
7e7a9efdb5 Fix the PowerPC DTrace copy functions. The kernel doesn't hold the same view to
the user map, so use the md copy in/out functions provided by the kernel.

MFC with:	r242723
2013-02-03 00:19:34 +00:00
Andriy Gapon
5583e07188 solaris compat: remove KM_ZERO
- there is no such flag in Solaris and derivatives
- the flag was added in an unrelated change
- the flag is not used

The proper way to allocate zeroed out memory is to use kmem_zalloc.

MFC after:	3 days
2013-02-02 11:41:05 +00:00
Andriy Gapon
13235aaa89 zfs: add MODULE_VERSION for zfsctrl
This should allow the kernel linker to easily detect a situation
when the module is present both in a kernel and in a preloaded file
(zfs.ko).

Reviewed by:	jhb
MFC after:	5 days
2013-02-02 11:35:18 +00:00
Andriy Gapon
ea84c62f93 spa_generate_rootconf: add support for old vdev labels
It seems that old ZFS versions (v15) completely omit "vdev_children"
property when there is a single child.

Reported by:	jase
Tested by:	jase
MFC after:	1 week
2013-01-26 10:34:17 +00:00
Xin LI
5c74885e99 MFV r245510:
improve the comment in txg.c

Obtained from:	Illumos (13910:f3454e0a097c)
MFC after:	2 weeks
2013-01-16 22:59:50 +00:00
Konstantin Belousov
614b9f9130 For zfs vnodes, use the standard inode number based hash algorithm.
Reviewed and tested by:	peter
Sponsored by:	The FreeBSD Foundation
MFC after:	5 days
2013-01-14 05:45:33 +00:00
Xin LI
290a1ba9a4 The current ZFS code expects ddt_zap_count to always succeed by asserting
the underlying zap_count() to return no errors.  However, it is possible
that the pool reaches to such a state where zap_count would return error,
leading to panics when a pool is imported.

This commit changes the ddt_zap_count to return error returned from
zap_count and handle the error appropriately.  With this change, it's now
possible to let zpool rollback damaged transaction groups and import the
pool.

Obtained from:	ZFS on Linux github (e8fd45a0f975c6b8ae8cd644714fc21f14fac2bf)
MFC after:	1 month
2013-01-10 19:26:56 +00:00
Andriy Gapon
f71fbb1d12 zfs: solaris doesn't have KM_ZERO, kmem_zalloc should be used instead
To do:		remove KM_ZERO declaration
Pointyhat to:	avg (for mindlessly using the pseudo-flag)
MFC after:	instantly (to fix stable/8 build)
2012-12-23 19:58:41 +00:00
Ryan Stone
6969ef6656 Correct a series of errors in the hand-rolled locking for drace_debug.c:
- Use spinlock_enter()/spinlock_exit() to prevent a thread holding a
  debug lock from being preempted to prevent other threads waiting
  on that lock from starvation.

- Handle the possibility of CPU migration in between the fetch of curcpu
  and the call to spinlock_enter() by saving curcpu in a local variable.

- Use memory barriers to prevent reordering of loads and stores of the
  data protected by the lock outside of the critical section

- Eliminate false sharing of the locks by moving them into the structures
  that they protect and aligning them to a cacheline boundary.

- Record the owning thread in the lock to make debugging future problems
  easier.

Reviewed by:	rpaulo (initial version)
MFC after:	2 weeks
2012-12-23 15:50:37 +00:00
Steven Hartland
5780c4a723 Added vfs.zfs.vdev.trim_on_init sysctl which allows full vdev trim on
initialisation to be enabled (1) / disabled (0) defaults to enabled.

This is useful for devices which have a slow trim speed and are either
new or have otherwise already been wiped e.g. secure erase.

PR:     kern/173116
Submitted by:   Steven Hartland
Approved by:    pjd (mentor)
2012-12-13 17:39:07 +00:00
Steven Hartland
c440a359ca Upgrades trim free request sizes before inserting them into to free map,
making range consolidation much more effective particularly for small
deletes.

This reduces memory used by the free map as well as reducing the number
of bio requests down to geom required to process all deletes.

In tests this achieved a factor of 10 reduction of trim ranges / geom
call downs.

While I'm here correct the description of zio_vdev_io_start.

PR:		kern/173254
Submitted by:	Steven Hartland
Approved by:	pjd (mentor)
2012-12-13 17:06:38 +00:00
Steven Hartland
7150222c0a Renamed zfs trim stats removing duplicate zio_trim identifier from the name
Added description option to kstats.
Added descriptions for zio_trim kstats

PR:		kern/173113
Submitted by:	Steven Hartland
Reviewed by:	pjd
Approved by:	pjd
MFC after:	2 weeks
2012-12-12 16:14:14 +00:00
Xin LI
2740382ebd Use SA_ZPL_CRTIME instead of SA_ZPL_CTIME for creation time.
Submitted by:	phil.stone at gmx.com
MFC after:	2 weeks
2012-12-03 04:25:37 +00:00
Andriy Gapon
289b3b96ac zfs_getpages: make use of vm_page_readahead_finish
Suggested by:	kib
MFC after:	5 days
2012-12-01 18:13:53 +00:00
Andriy Gapon
992ffc58ae gfs_file_inactive: replace bad code with ugly code
Also, make it explicit that V_XATTRDIR is not properly supported in gfs
code yet.

The bad code was plain incorrect: (a) it spoiled handling of v_usecount
reaching zero and (b) it leaked v_holdcnt.

The ugly code employs potentially unsafe locking tricks.

Ideally we should separate vnode lifecycle and gfs node lifecycle.
A gfs node should have its own reference count where its child nodes
should be accounted.

PR:		kern/151111
Reviewed by:	kib
MFC after:	13 days
2012-12-01 18:12:55 +00:00
Martin Matuska
7faa32552f MFV r243395:
Introduce a new dataset aclmode setting "restricted" to protect ACL's
being destroyed or corrupted by a drive-by chmod.

illumos-gate 13889:a67716f16746
3254 add support in zfs for aclmode=restricted

References:
https://www.illumos.org/issues/3254

MFC after:	2 weeks
2012-11-26 12:24:39 +00:00
Martin Matuska
53e5858c68 Add loader(8) tunable to enable/disable nopwrite functionality:
vfs.zfs.nopwrite_enabled

MFC after:	2 weeks
2012-11-25 16:54:43 +00:00
Martin Matuska
dd801aa546 MFV r243013 and r243267:
Import the zio nop-write improvement from Illumos. To reduce I/O,
nop-write omits overwriting data if the checksum (cryptographically
secure) of new data matches the checksum of existing data.
It also saves space if snapshots are in use.

It currently works only on datasets with enabled compression, disabled
deduplication and sha256 checksums.

IllumOS 13887:196932ec9e6a and 13888:7204b3392a58
3236 zio nop-write

References:
https://www.illumos.org/issues/3236

MFC after:	2 weeks
2012-11-25 16:32:07 +00:00
Andriy Gapon
3a0e1b57bb zfs_freebsd_reclaim: remove a stray variable
... which leaked from a subsequent local change.
Unfortunately I noticed that only after commit.

MFC after:	5 weeks
X-MFC with:	r243520
2012-11-25 15:46:29 +00:00
Andriy Gapon
4ff1c77d22 zfs: overhaul zfs-vfs glue for vnode life-cycle management
* There is no need for the delayed destruction of znodes via taskqueue,
now that we do not need to fear recursion from getnewvnode into
zfs_inactive and zfs_freebsd_reclaim, thus making znode/vnode state
machine a bit simpler.

* More complete porting of zfs_inactive from Solaris VFS model to FreeBSD
vop_inactive and vop_reclaim model.  All destructive actions are done
in zfs_freebsd_reclaim.
This allows to simplify zfs_zget logic.

* Allow zfs_zget to return a doomed vnode if the current thread already
has an exclusive lock on the vnode.

* Clean up Solaris-isms like bailing out of reclaim/inactive on certain
values of v_usecount (aka v_count) or directly messing with this counter.

* Do not clear z_vnode while znode is still accessible.
z_vnode should be cleared only after zfs_znode_dmu_fini.
Otherwise zfs_zget may get an effectively half-deconstructed znode.
This allows to simplify zfs_zget logic further.

The above changes fix at least two known/reported problems:

o An indefinite wait in the following code path:
vgone -> VOP_RECLAIM -> zfs_freebsd_reclaim -> vnode_destroy_vobject ->
put_pages -> zfs_write -> zil_commit -> zfs_zget
This happened because vgone marks a vnode as VI_DOOMED before calling
VOP_RECLAIM, but zfs_zget would not return a doomed vnode under any
circumstances.
The fix in this change is not complete as it won't fix a deadlock between
two threads doing VOP_RECLAIM where one thread is in zil_commit trying to
zfs_zget a znode/vnode being reclaimed by the other thread, which would be
blocked trying to enter zil_commit.  This type of deadlock has not been
reported as of now.

o An indefinite wait in the unmount path caused by a znode "falling through
the cracks" in inactive+reclaim.  This would happen if the znode is unlinked
while its vnode is still active.

To Do: pass locking flags parameter to zfs_zget, so that the zfs-vfs
glue code doesn't have to re-lock a vnode but could ask for proper locking
from the very start.  This would also allow for the higher level code to
obtain a doomed vnode when it is expected/requested.  Or to avoid blocking
when it is not allowed (see zil_commit example above).

ffs_vgetf seems like a good source of inspiration.

Tested by:	Willem Jan Withagen <wjw@digiware.nl>
MFC after:	6 weeks
2012-11-25 15:33:26 +00:00
Andriy Gapon
7ca5310ea3 zfs_fhtovp: there is no reason to amend lock flags with LK_RETRY here
MFC after:	12 days
2012-11-25 15:07:27 +00:00
Andriy Gapon
7192f62bcc add zfs_bmap to aid vnode_pager_haspage
... otherwise zfs_getpages would mostly be called with one page at a time.

It is expected that ZFS VOP_BMAP is only called from vnode_pager_haspage.
Since ZFS files can have variable block sizes and also because we don't
really know if any given blocks are consecutive, we can not really report
any additional blocks behind or ahead of a given block.  Since physical
block numbers do not make sense for ZFS, we do not do any real translation
and thus pass back blk = lblk.  The net effect is that vnode_pager_haspage
knows that the block exists and that the pages backed by the block can be
accessed.  vnode_pager_haspage may be wrong about the exact count of the
pages backed by the block, because of a variable block size, which
vnode_pager_haspage doesn't really know - it only knows max block size in
a filesystem.  So pages from multiple blocks can be passed to zfs_getpages,
but that is expected and correctly handled.

vnode_pager should not call zfs_bmap for any other reason, because ZFS
implements VOP_PUTPAGES and thus vnode_pager_generic_getpages is not used.

vfs_cluster code vfs_bio code should not be called for ZFS, because ZFS does
not use buffer cache layer.

Also, ZFS does not use vn_bmap_seekhole, it has its prviate mechanism for
working with holes.

The above list should cover all the current calls to VOP_BMAP.

Reviewed by:	kib
MFC after:	6 weeks
2012-11-25 15:01:12 +00:00