illumos/illumos-gate@1d3f896f54https://www.illumos.org/issues/5981
When dmu_objset_find_dp gets called with a read lock held, it fans out
the work to the task queue. Each task in turn acquires its own read
lock before calling the callback. If during this process anyone tries
to a acquire a write lock, it will stall all read lock requests.Thus
the tasks will never finish, the read lock of the caller will never
get freed and the write lock never acquired. deadlock.
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Dan McDonald <danmcd@omniti.com>
Approved by: Robert Mustacchi <rm@joyent.com>
Author: Arne Jansen <jansen@webgods.de>
read workload by splitting the single teardown rrw lock into
RRM_NUM_LOCKS (17) of them.
Read acquisitions are randomly distributed among these locks based
on curthread pointer. Write acquisitions are going to all the
locks, which for the usage of this type of lock should be rare.
Illumos issue:
5008 lock contention (rrw_exit) while running a read only load
MFC after: 2 weeks
- better ACL caching and speedup of ACL permission checks
- faster handling of stat()
- lowered mutex contention in the read/writer lock (rrwlock)
- several related bugfixes
Detailed information (OpenSolaris onnv changesets and Bug IDs):
9749:105f407a2680
6802734 Support for Access Based Enumeration (not used on FreeBSD)
6844861 inconsistent xattr readdir behavior with too-small buffer
9866:ddc5f1d8eb4e
6848431 zfs with rstchown=0 or file_chown_self privilege allows user to "take" ownership
9981:b4907297e740
6775100 stat() performance on files on zfs should be improved
6827779 rrwlock is overly protective of its counters
10143:d2d432dfe597
6857433 memory leaks found at: zfs_acl_alloc/zfs_acl_node_alloc
6860318 truncate() on zfsroot succeeds when file has a component of its path set without access permission
10232:f37b85f7e03e
6865875 zfs sometimes incorrectly giving search access to a dir
10250:b179ceb34b62
6867395 zpool_upgrade_007_pos testcase panic'd with BAD TRAP: type=e (#pf Page fault)
10269:2788675568fd
6868276 zfs_rezget() can be hazardous when znode has a cached ACL
10295:f7a18a1e9610
6870564 panic in zfs_getsecattr
Approved by: delphij (mentor)
Obtained from: OpenSolaris (multiple Bug IDs)
MFC after: 2 weeks
This bring huge amount of changes, I'll enumerate only user-visible changes:
- Delegated Administration
Allows regular users to perform ZFS operations, like file system
creation, snapshot creation, etc.
- L2ARC
Level 2 cache for ZFS - allows to use additional disks for cache.
Huge performance improvements mostly for random read of mostly
static content.
- slog
Allow to use additional disks for ZFS Intent Log to speed up
operations like fsync(2).
- vfs.zfs.super_owner
Allows regular users to perform privileged operations on files stored
on ZFS file systems owned by him. Very careful with this one.
- chflags(2)
Not all the flags are supported. This still needs work.
- ZFSBoot
Support to boot off of ZFS pool. Not finished, AFAIK.
Submitted by: dfr
- Snapshot properties
- New failure modes
Before if write requested failed, system paniced. Now one
can select from one of three failure modes:
- panic - panic on write error
- wait - wait for disk to reappear
- continue - serve read requests if possible, block write requests
- Refquota, refreservation properties
Just quota and reservation properties, but don't count space consumed
by children file systems, clones and snapshots.
- Sparse volumes
ZVOLs that don't reserve space in the pool.
- External attributes
Compatible with extattr(2).
- NFSv4-ACLs
Not sure about the status, might not be complete yet.
Submitted by: trasz
- Creation-time properties
- Regression tests for zpool(8) command.
Obtained from: OpenSolaris
