MFC r300142:
Ensure that ftruncate(2) is performed synchronously when file is
opened in O_SYNC mode, at least for UFS.

MFC r299412:
Add vfs_hash_ref(9) function, which finds a vnode by the hash value
and returns it referenced.

MFC r299408:
Style: wrap long lines.

MFC r298982:
Add EVFILT_VNODE open, read and close notifications.

MFC r298984:
Correct wording.

MFC r287831 (by cem):
Note DOOMED vnodes with NOTE_REVOKE.

MFC r287107:

Make vfs_unmountall() unmount /dev after /, not before. The only
reason this didn't result in an unclean shutdown is that devfs ignores
MNT_FORCE flag.

Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D3467

MFC r287033:

After r286237 it should be fine to call vgone(9) on a busy GEOM vnode;
remove KASSERT that would prevent forced devfs unmount from working.

Sponsored by: The FreeBSD Foundation

MFC r287886:

Fix kqueue write events for files > 2GB

Sponsored by: Multiplay

MFC of 281677:

More accurately collect name-cache statistics in sysctl functions
sysctl_debug_hashstat_nchash() and sysctl_debug_hashstat_rawnchash().
These changes are in preparation for allowing changes in the size
of the vnode hash tables driven by increases and decreases in the
maximum number of vnodes in the system.

Reviewed by: kib@
Phabric: D2265

MFC of 287497:

Track changes to kern.maxvnodes and appropriately increase or decrease
the size of the name cache hash table (mapping file names to vnodes)
and the vnode hash table (mapping mount point and inode number to vnode).
An appropriate locking strategy is the key to changing hash table sizes
while they are in active use.

Reviewed by: kib
Tested by: Peter Holm
Differential Revision: https://reviews.freebsd.org/D2265

MFC r283601:
Add V_MNTREF flag, to indicate that caller of vn_start*_write() already
owns a reference on the mount point, and the functions can consume it.

MFC r279362:
The VNASSERT in vflush() FORCECLOSE case is trying to panic early to
prevent errors from yanking devices out from under filesystems. Only
care about special vnodes on devfs, special nodes on other kinds of
filesystems do not have special properties.

MFC r276008:
Add VN_OPEN_NAMECACHE flag for vn_open_cred(9), which requests that
the created file name was cached. Use the flag for core dumps.

MFC r273131:
When vnode bypass cannot be performed on the cdev file descriptor for
read/write/poll/ioctl, call standard vnode filedescriptor fop.

MFC r272534:
Add IO_RANGELOCKED flag for vn_rdwr(9), which specifies that vnode is
not locked, but range is.

Add function and wrapper to switch lockmgr and vnode lock back to
auto-promotion of shared to exclusive.

Approved by: re (gjb)

MFC r268612:
Add helper helper vfs_write_suspend_umnt().

Fix the bug in the FFS unmount, when suspension failed, the ufs
extattrs were not reinitialized.

MFC r268606:
Generalize vn_get_ino() to allow filesystems to use custom vnode
producer. Convert inline copies of vn_get_ino() in msdosfs and cd9660
into the uses of vn_get_ino_gen().

MFC r267564:
In msdosfs_setattr(), add a check for result of the utimes(2) permissions test.
Refactor the permission checks for utimes(2).

MFC r287886:

Fix kqueue write events for files > 2GB

Sponsored by: Multiplay

MFC of 281677:

More accurately collect name-cache statistics in sysctl functions
sysctl_debug_hashstat_nchash() and sysctl_debug_hashstat_rawnchash().
These changes are in preparation for allowing changes in the size
of the vnode hash tables driven by increases and decreases in the
maximum number of vnodes in the system.

Reviewed by: kib@
Phabric: D2265

MFC of 287497:

Track changes to kern.maxvnodes and appropriately increase or decrease
the size of the name cache hash table (mapping file names to vnodes)
and the vnode hash table (mapping mount point and inode number to vnode).
An appropriate locking strategy is the key to changing hash table sizes
while they are in active use.

Reviewed by: kib
Tested by: Peter Holm
Differential Revision: https://reviews.freebsd.org/D2265

MFC r283601:
Add V_MNTREF flag, to indicate that caller of vn_start*_write() already
owns a reference on the mount point, and the functions can consume it.

MFC r279362:
The VNASSERT in vflush() FORCECLOSE case is trying to panic early to
prevent errors from yanking devices out from under filesystems. Only
care about special vnodes on devfs, special nodes on other kinds of
filesystems do not have special properties.

MFC r276008:
Add VN_OPEN_NAMECACHE flag for vn_open_cred(9), which requests that
the created file name was cached. Use the flag for core dumps.

MFC r273131:
When vnode bypass cannot be performed on the cdev file descriptor for
read/write/poll/ioctl, call standard vnode filedescriptor fop.

MFC r272534:
Add IO_RANGELOCKED flag for vn_rdwr(9), which specifies that vnode is
not locked, but range is.

Add function and wrapper to switch lockmgr and vnode lock back to
auto-promotion of shared to exclusive.

Approved by: re (gjb)

MFC r268612:
Add helper helper vfs_write_suspend_umnt().

Fix the bug in the FFS unmount, when suspension failed, the ufs
extattrs were not reinitialized.

MFC r268606:
Generalize vn_get_ino() to allow filesystems to use custom vnode
producer. Convert inline copies of vn_get_ino() in msdosfs and cd9660
into the uses of vn_get_ino_gen().

MFC r267564:
In msdosfs_setattr(), add a check for result of the utimes(2) permissions test.
Refactor the permission checks for utimes(2).