MFC r307218:
Fix a race in vm_page_busy_sleep(9).

MFC r298809, r298817
Minor spelling fixes.

MFC r285384:
Do not allow creation of the dirty buffers for the dead buffer objects.

MFC r284887:
Handle errors from background write of the cylinder group blocks.

MFC r284927:
Simplify code.

Approved by: re (gjb)

MFC r284719:
Only take previous buffer queue lock (olock) when needed for REMFREE
in binsfree().

MFC: r281960
MAXBSIZE defines both the largest UFS block size and the
largest size for a buffer in the buffer cache. This patch
defines a new constant MAXBCACHEBUF, which is the largest
size for a buffer in the buffer cache. Having a separate
constant allows MAXBCACHEBUF to be set larger than MAXBSIZE
on a per-architecture basis, so that NFS can do larger read/writes
for these architectures. It modifies sys/param.h so that BKVASIZE
can also be set on a per-architecture basis.
A couple of cases where NFS used MAXBSIZE instead of NFS_MAXBSIZE
is fixed as well.

MFC r282085:
Partially revert r255986: do not call VOP_FSYNC() when helping
bufdaemon in getnewbuf(), do use buf_flush(). The difference is that
bufdaemon uses TRYLOCK to get buffer locks, which allows calls to
getnewbuf() while another buffer is locked.

MFC r275619:
Check for bo_bufobj->bo_object for NULL and cache the value in local
variable to avoid NULL dereference in getnewbuf_reuse_bp(). The vnode
owning the buffer is not locked there.

MFC r273638:
Revert somewhat hackish geom_disk optimization, committed as part of r256880,
and the following r273143 commit, supposed to workaround introduced issue by
quite innocent-looking change.

While there is no clear understanding why, but r273143 is accused in data
corruption in some environments with high I/O load. I personally don't see
any problem in that commit, and possibly it is just a trigger to some other
bug somewhere, but better safe then sorry for now.

Requested by: scottl@

MFC r273143: Remove setting BIO_DONE flag for BIOs that have done() method.

This fixes use-after-free, caused by geom_disk, completing same BIO twice
to save extra allocation, and getting BIO_DONE set after the first.

MFC: r272718

Make kern.nswbuf tunable from loader.

MFC of 269533 (by mckusick):

Add support for multi-threading of soft updates.

Replace a single soft updates thread with a thread per FFS-filesystem
mount point. The threads are associated with the bufdaemon process.

Reviewed by: kib
Tested by: Peter Holm and Scott Long
MFC after: 2 weeks
Sponsored by: Netflix

MFC of 269853 (by kib):

Revision r269457 removed the Giant around mount and unmount code, but
r269533, which was tested before r269457 was committed, implicitely
relied on the Giant to protect the manipulations of the softdepmounts
list. Use softdep global lock consistently to guarantee the list
structure now.

Insert the new struct mount_softdeps into the softdepmounts only after
it is sufficiently initialized, to prevent softdep_speedup() from
accessing bare memory. Similarly, remove struct mount_softdeps for
the unmounted filesystem from the tailq before destroying structure
rwlock.

Reported and tested by: pho
Reviewed by: mckusick
Sponsored by: The FreeBSD Foundation

MFC r267255:
Change the nblock mutex to rwlock.

MFC r267264:
Devolatile as needed.

MFC r267226:
Initialize the pbuf counter for directio using SYSINIT.
Mark ffs_rawread.c as requiring both ffs and directio options to be
compiled into the kernel. Add ffs_rawread.c to the list of ufs.ko
module' sources.

MFC Alexander Motin's GEOM direct dispatch work:

r256603:
Introduce new function devstat_end_transaction_bio_bt(), adding new argument
to specify present time. Use this function to move binuptime() out of lock,
substantially reducing lock congestion when slow timecounter is used.

r256606:
Move g_io_deliver() out of the lock, as required for direct dispatch.
Move g_destroy_bio() out too to reduce lock scope even more.

r256607:
Fix passing uninitialized bio_resid argument to g_trace().

r256610:
Add unmapped I/O support to GEOM RAID.

r256830:
Restore BIO_UNMAPPED and BIO_TRANSIENT_MAPPING in biodonne() when unmapping
temporary mapped buffer. That fixes double unmap if biodone() called twice
for the same BIO (but with different done methods).

r256880:
Merge GEOM direct dispatch changes from the projects/camlock branch.

When safety requirements are met, it allows to avoid passing I/O requests
to GEOM g_up/g_down thread, executing them directly in the caller context.
That allows to avoid CPU bottlenecks in g_up/g_down threads, plus avoid
several context switches per I/O.

r259247:
Fix bug introduced at r256607. We have to recalculate bp_resid here since
sizes of original and completed requests may differ due to end of media.

Testing of the stable/10 merge was done by Netflix, but all of the credit
goes to Alexander and iX Systems.

Submitted by: mav
Sponsored by: iX Systems

MFC r256614:
- Take BIO lock in biodone() only when there is no completion callback set
and so we should wake up thread waiting in biowait().
- Remove msleep() timeout from biowait(). It was added 11 years ago, when
there was no locks used, and it should not be needed any more.

MFC r285384:
Do not allow creation of the dirty buffers for the dead buffer objects.

MFC r284887:
Handle errors from background write of the cylinder group blocks.

MFC r284927:
Simplify code.

Approved by: re (gjb)

MFC r284719:
Only take previous buffer queue lock (olock) when needed for REMFREE
in binsfree().

MFC: r281960
MAXBSIZE defines both the largest UFS block size and the
largest size for a buffer in the buffer cache. This patch
defines a new constant MAXBCACHEBUF, which is the largest
size for a buffer in the buffer cache. Having a separate
constant allows MAXBCACHEBUF to be set larger than MAXBSIZE
on a per-architecture basis, so that NFS can do larger read/writes
for these architectures. It modifies sys/param.h so that BKVASIZE
can also be set on a per-architecture basis.
A couple of cases where NFS used MAXBSIZE instead of NFS_MAXBSIZE
is fixed as well.

MFC r282085:
Partially revert r255986: do not call VOP_FSYNC() when helping
bufdaemon in getnewbuf(), do use buf_flush(). The difference is that
bufdaemon uses TRYLOCK to get buffer locks, which allows calls to
getnewbuf() while another buffer is locked.

MFC r275619:
Check for bo_bufobj->bo_object for NULL and cache the value in local
variable to avoid NULL dereference in getnewbuf_reuse_bp(). The vnode
owning the buffer is not locked there.

MFC r273638:
Revert somewhat hackish geom_disk optimization, committed as part of r256880,
and the following r273143 commit, supposed to workaround introduced issue by
quite innocent-looking change.

While there is no clear understanding why, but r273143 is accused in data
corruption in some environments with high I/O load. I personally don't see
any problem in that commit, and possibly it is just a trigger to some other
bug somewhere, but better safe then sorry for now.

Requested by: scottl@

MFC r273143: Remove setting BIO_DONE flag for BIOs that have done() method.

This fixes use-after-free, caused by geom_disk, completing same BIO twice
to save extra allocation, and getting BIO_DONE set after the first.

MFC: r272718

Make kern.nswbuf tunable from loader.

MFC of 269533 (by mckusick):

Add support for multi-threading of soft updates.

Replace a single soft updates thread with a thread per FFS-filesystem
mount point. The threads are associated with the bufdaemon process.

Reviewed by: kib
Tested by: Peter Holm and Scott Long
MFC after: 2 weeks
Sponsored by: Netflix

MFC of 269853 (by kib):

Revision r269457 removed the Giant around mount and unmount code, but
r269533, which was tested before r269457 was committed, implicitely
relied on the Giant to protect the manipulations of the softdepmounts
list. Use softdep global lock consistently to guarantee the list
structure now.

Insert the new struct mount_softdeps into the softdepmounts only after
it is sufficiently initialized, to prevent softdep_speedup() from
accessing bare memory. Similarly, remove struct mount_softdeps for
the unmounted filesystem from the tailq before destroying structure
rwlock.

Reported and tested by: pho
Reviewed by: mckusick
Sponsored by: The FreeBSD Foundation

MFC r267255:
Change the nblock mutex to rwlock.

MFC r267264:
Devolatile as needed.

MFC r267226:
Initialize the pbuf counter for directio using SYSINIT.
Mark ffs_rawread.c as requiring both ffs and directio options to be
compiled into the kernel. Add ffs_rawread.c to the list of ufs.ko
module' sources.

MFC Alexander Motin's GEOM direct dispatch work:

r256603:
Introduce new function devstat_end_transaction_bio_bt(), adding new argument
to specify present time. Use this function to move binuptime() out of lock,
substantially reducing lock congestion when slow timecounter is used.

r256606:
Move g_io_deliver() out of the lock, as required for direct dispatch.
Move g_destroy_bio() out too to reduce lock scope even more.

r256607:
Fix passing uninitialized bio_resid argument to g_trace().

r256610:
Add unmapped I/O support to GEOM RAID.

r256830:
Restore BIO_UNMAPPED and BIO_TRANSIENT_MAPPING in biodonne() when unmapping
temporary mapped buffer. That fixes double unmap if biodone() called twice
for the same BIO (but with different done methods).

r256880:
Merge GEOM direct dispatch changes from the projects/camlock branch.

When safety requirements are met, it allows to avoid passing I/O requests
to GEOM g_up/g_down thread, executing them directly in the caller context.
That allows to avoid CPU bottlenecks in g_up/g_down threads, plus avoid
several context switches per I/O.

r259247:
Fix bug introduced at r256607. We have to recalculate bp_resid here since
sizes of original and completed requests may differ due to end of media.

Testing of the stable/10 merge was done by Netflix, but all of the credit
goes to Alexander and iX Systems.

Submitted by: mav
Sponsored by: iX Systems

MFC r256614:
- Take BIO lock in biodone() only when there is no completion callback set
and so we should wake up thread waiting in biowait().
- Remove msleep() timeout from biowait(). It was added 11 years ago, when
there was no locks used, and it should not be needed any more.