Document kernel API for vfs_busy(), vfs_mount(), vfs_unbusy(), and

vinvalbuf().

Submitted by: Chad David <davidc@acns.ab.ca>

4 files changed, 364 insertions, 0 deletions

diff --git a/share/man/man9/vfs_busy.9 b/share/man/man9/vfs_busy.9
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+.\"
+.\" Copyright (C) 2001 Chad David <davidc@acns.ab.ca>. All rights reserved.
+.\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\"    notice(s), this list of conditions and the following disclaimer as
+.\"    the first lines of this file unmodified other than the possible
+.\"    addition of one or more copyright notices.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\"    notice(s), this list of conditions and the following disclaimer in the
+.\"    documentation and/or other materials provided with the distribution.
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY
+.\" EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+.\" WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+.\" DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE LIABLE FOR ANY
+.\" DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+.\" (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+.\" SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+.\" CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
+.\" DAMAGE.
+.\"
+.\" $FreeBSD$
+.\"
+.Dd July 8, 2001
+.Dt VFS_BUSY 9
+.Os
+.Sh NAME
+.Nm vfs_busy
+.Nd "Marks a mount point as busy."
+.Sh SYNOPSIS
+.Ft int
+.Fo vfs_busy
+.Fa "struct mount *mp"
+.Fa "int flags"
+.Fa "struct mtx *interlkp"
+.Fa "struct proc *p"
+.Fc
+.Sh DESCRIPTION
+The
+.Nm
+function marks a mount point as busy.  The purpose of this
+function is to synchronize access to a mount point.  It also
+delays unmounting by sleeping on mp if the MNTK_UNMOUNT flag
+is set in mp->mnt_kern_flag and the LK_NOWAIT flag is NOT set.
+.Pp
+Its arguments are:
+.Bl -tag -width interlkp
+.It Ar mp
+The mount point to busy.
+.It Ar flags
+Flags controlling the operation of
+.Nm
+.
+.Pp
+LK_NOWAIT - do not sleep if MNTK_UNMOUNT is set.
+.It Ar interlkp
+The interlock mutex for mp->mount_lock.  If there is any chance
+the mount point is being unmounted and LK_NOWAIT is not set then
+interlock must be valid locked mutex.
+.It Ar p
+The process responsible for this call.
+.El
+.Sh LOCKS
+If interlkp is a valid pointer it must be locked on entry,
+and it will not be unlocked even on error.
+.Sh RETURN VALUES
+A 0 value is returned on success.  If the mount point is being
+unmounted ENOENT will always be returned.
+.Sh ERRORS
+.Bl -tag
+.It Bq ENOENT
+The mount point is being unmounted (MNTK_UNMOUNT is set).
+.El
+.Sh AUTHORS
+This man page was written by Chad David.
diff --git a/share/man/man9/vfs_mount.9 b/share/man/man9/vfs_mount.9
new file mode 100644
index 0000000..7e04fc0
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+.\"
+.\" Copyright (C) 2001 Chad David <davidc@acns.ab.ca>. All rights reserved.
+.\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\"    notice(s), this list of conditions and the following disclaimer as
+.\"    the first lines of this file unmodified other than the possible
+.\"    addition of one or more copyright notices.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\"    notice(s), this list of conditions and the following disclaimer in the
+.\"    documentation and/or other materials provided with the distribution.
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY
+.\" EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+.\" WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+.\" DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE LIABLE FOR ANY
+.\" DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+.\" (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+.\" SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+.\" CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
+.\" DAMAGE.
+.\"
+.\" $FreeBSD$
+.\"
+.Dd July 8, 2001
+.Dt VFS_MOUNT 9
+.Os
+.Sh NAME
+.Nm vfs_mount
+.Nd "Generic filesystem mount function"
+.Sh SYNOPSIS
+.Fd #include <sys/mount.h>
+.Ft int
+.Fo vfs_mount
+.Fa "struct proc *vp"
+.Fa "char *fstype"
+.Fa "char *fspath"
+.Fa "int fsflags"
+.Fa "void *fsdata"
+.Fc
+.Sh DESCRIPTION
+The
+.Nm
+function handles the generic portion of mounting a filesystem,
+and calls the filesystem specific mount function after verifying
+its parameters and setting up the structures expected by the
+underlying mount code.
+.Pp
+.Nm
+is called directly by the mount system call.
+.Pp
+Its arguments are:
+.Bl -tag -width fsflags
+.It Ar p
+The process responsible for this call.
+.It Ar fstype
+The type of filesystem being mounted.
+.It Ar fspath
+The path to the mount point of the filesystem.
+.It Ar fsflags
+Flags controlling the mount. See mount(8) for details.
+.Pp
+MNT_EXPORTED MNT_NOSUID MNT_NODEV MNT_UPDATE MNT_RELOAD
+MNT_FORCE MNT_ASYNC MNT_SYNCHRONOUS MNT_UNION MNT_NOATIME
+MNT_SNAPSHOT MNT_NOCLUSTERR MNT_NOCLUSTERW MNT_IGNORE
+MNT_UNION MNT_NOSYMFOLLOW
+.It Ar fsdata
+Filesystem specific data structure.  It is in userspace
+when passed to
+.Nm
+and is left untouched when passed to filesystems mount().
+.El
+.Sh RETURN VALUES
+A 0 value is returned on success. 
+.Sh ERRORS
+.Bl -tag -width Er
+.It Bq Er ENAMETOOLONG
+The fs type or the mount point path is too long or any individual
+path component is too long.
+.It Bq Er EPERM
+Permission denied.  There are a number of reason this can occur
+ranging from the user not having permission to mount a filesystem
+to the securelevel being to high to load the fstype module.
+.It Bq Er EINVAL
+Invalid operation (ex: trying to update a non mount-point).
+.It Bq Er ENOENT
+The mount point does not exist (from namei)
+.It Bq Er ELOOP
+The mount point is a muddle of links (from namei)
+.It Bq Er EOPNOTSUPP
+The operation is not supported (ex: reloading a r/w filesystem)
+.It Bq Er EBUSY
+The mount point is busy or is not really a mount point (on update)
+.It Bq Er ENOTDIR
+The mount point is not a directory
+.It Bq Er ENODEV
+The kernel linker was unable to load the specified fstype or
+was unable to find the specified fstype module.
+.Pp
+Other errors can be returned by the filesystems mount() and
+you should check the specific filesystem for details.  Also
+this call relies on a large number of other kernel services
+whose errors it returns so this list my not be exhaustive.
+.El
+.Sh SEE ALSO
+.Xr mount 2
+.Xr mount 8
+.Xr mount 9
+.Xr ffs_mount 9
+vfs.usermount
+.Sh AUTHORS
+This man page was written by Chad David.
diff --git a/share/man/man9/vfs_unbusy.9 b/share/man/man9/vfs_unbusy.9
new file mode 100644
index 0000000..31c85ff
--- /dev/null
+++ b/share/man/man9/vfs_unbusy.9
@@ -0,0 +1,64 @@
+.\"
+.\" Copyright (C) 2001 Chad David <davidc@acns.ab.ca>. All rights reserved.
+.\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\"    notice(s), this list of conditions and the following disclaimer as
+.\"    the first lines of this file unmodified other than the possible
+.\"    addition of one or more copyright notices.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\"    notice(s), this list of conditions and the following disclaimer in the
+.\"    documentation and/or other materials provided with the distribution.
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY
+.\" EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+.\" WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+.\" DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE LIABLE FOR ANY
+.\" DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+.\" (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+.\" SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+.\" CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
+.\" DAMAGE.
+.\"
+.\" $FreeBSD$
+.\"
+.Dd July 8, 2001
+.Dt VFS_UNBUSY 9
+.Os
+.Sh NAME
+.Nm vfs_unbusy
+.Nd "Unbusy a mount point.
+.Sh SYNOPSIS
+.Ft void
+.Fo vfs_unbusy
+.Fa "struct mount *mp"
+.Fa "struct proc *p"
+.Fc
+.Sh DESCRIPTION
+The
+.Nm
+function unbusys (unlocks) a mount point by unlocking
+mp->mnt_lock.  The lock is typically aquired by calling
+vfs_busy() prior to this call.
+.Pp
+Its arguments are:
+.Bl -tag -width uap
+.It Ar mp
+The mount point to unbusy (unlock).
+.It Ar p
+The process responsible for this call.
+.El
+.Sh LOCKS
+.Ar mnt_lock
+must be locked in
+.Ar mp
+prior to calling
+this function, and it will be unlocked upon return.
+.Sh SEE ALSO
+.Xr vfs_busy 9
+.Sh AUTHORS
+This man page was written by Chad David.
diff --git a/share/man/man9/vinvalbuf.9 b/share/man/man9/vinvalbuf.9
new file mode 100644
index 0000000..fdcfb1d
--- /dev/null
+++ b/share/man/man9/vinvalbuf.9
@@ -0,0 +1,104 @@
+.\"
+.\" Copyright (C) 2001 Chad David <davidc@acns.ab.ca>. All rights reserved.
+.\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\"    notice(s), this list of conditions and the following disclaimer as
+.\"    the first lines of this file unmodified other than the possible
+.\"    addition of one or more copyright notices.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\"    notice(s), this list of conditions and the following disclaimer in the
+.\"    documentation and/or other materials provided with the distribution.
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY
+.\" EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+.\" WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+.\" DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE LIABLE FOR ANY
+.\" DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+.\" (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+.\" SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+.\" CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
+.\" DAMAGE.
+.\"
+.\" $FreeBSD$
+.\"
+.Dd July 7, 2001
+.Dt VINVALBUF 9
+.Os
+.Sh NAME
+.Nm vinvalbuf
+.Nd "Flushes and invalidates all buffers associated with a vnode"
+.Sh SYNOPSIS
+.Fd #include <sys/vnode.h>
+.Ft int
+.Fo vinvalbuf
+.Fa "struct vnode *vp"
+.Fa "int flags"
+.Fa "struct ucred *cred"
+.Fa "struct proc *p"
+.Fa "int slpflag"
+.Fa "int slptimeo"
+.Fc
+.Sh DESCRIPTION
+The
+.Nm
+function invalidates all of the buffers associated with the given vnode.
+This includes buffers on the clean list and the dirty list.  If the V_SAVE
+flag is specified then the buffers on the dirty list are synced prior to being
+released.  If there is a VM Object associated with the vnode it is removed.
+.Pp
+Its arguments are:
+.Bl -tag -width spltimeo
+.It Ar vp
+A pointer to the vnode whose buffers will be invalidated.
+.It Ar flags
+The only supported flag is V_SAVE and it indicates that dirty buffers should by synced.
+.It Ar cred
+The user credentials that are used to
+.Fn VOP_FSYNC ""
+buffers if V_SAVE is set.
+.It Ar p
+The process responsible for this call.
+.It Ar slpflag
+The slp flag that will be used in the priority of any sleeps in the function.
+.It Ar slptimeo
+The timeout for any sleeps in the function.
+.El
+.Sh LOCKS
+The vnode is assumed to be locked prior to the call and remains locked upon return.
+.Pp
+Giant must be held by prior to the call and remains locked upon return.
+.Sh RETURN VALUES
+A 0 value is returned on success. 
+.Sh PSEUDOCODE
+.Bd -literal
+	vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY, p);
+	error = vinvalbuf(devvp, V_SAVE, cred, p, 0, 0);
+	VOP_UNLOCK(devvp, 0, p);
+	if (error)
+		return (error);
+.Ed
+.Sh ERRORS
+.Bl -tag -width Er
+.It Bq Er ENOSPC
+The filesystem is full. (With V_SAVE)
+.It Bq Er EDQUOT
+Disc quota exceeded. (With V_SAVE)
+.It Bq Er EWOULDBLOCK
+Sleep operation timed out (See slptimeo)
+.It Bq Er ERESTART
+A signal needs to be delivered and the system call should be restarted (With PCATCH set in slpflag)
+.It Bq Er EINTR
+The system has been interrupted by a signal (With PCATCH set in slpflag)
+.El
+.Sh SEE ALSO
+.Xr brelse 9
+.Xr bremfree 9
+.Xr VOP_FSYNC 9
+.Xr tsleep 9
+.Sh AUTHORS
+This man page was written by Chad David.