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Add man page for VOP_FDATASYNC(9)

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Reviewed by:    kib
MFC after:      2 weeks
Sponsored by:   The FreeBSD Foundation
Differential Revision:  https://reviews.freebsd.org/D19678
This commit is contained in:
asomers 2019-03-29 02:44:20 +00:00
parent e205beed0a
commit ed728d155c
2 changed files with 24 additions and 4 deletions
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1
share/man/man9/Makefile
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@ -2233,6 +2233,7 @@ MLINKS+=VOP_ATTRIB.9 VOP_GETATTR.9 \
MLINKS+=VOP_CREATE.9 VOP_MKDIR.9 \
VOP_CREATE.9 VOP_MKNOD.9 \
VOP_CREATE.9 VOP_SYMLINK.9
MLINKS+=VOP_FSYNC.9 VOP_FDATASYNC.9
MLINKS+=VOP_GETPAGES.9 VOP_PUTPAGES.9
MLINKS+=VOP_INACTIVE.9 VOP_RECLAIM.9
MLINKS+=VOP_LOCK.9 vn_lock.9 \

27
share/man/man9/VOP_FSYNC.9
View File

@ -28,20 +28,27 @@
.\"
.\" $FreeBSD$
.\"
.Dd July 24, 1996
.Dd March 22, 2019
.Dt VOP_FSYNC 9
.Os
.Sh NAME
.Nm VOP_FDATASYNC ,
.Nm VOP_FSYNC
.Nd flush file system buffers for a file
.Sh SYNOPSIS
.In sys/param.h
.In sys/vnode.h
.Ft int
.Fn VOP_FDATASYNC "struct vnode *vp" "struct thread *td"
.Ft int
.Fn VOP_FSYNC "struct vnode *vp" "int waitfor" "struct thread *td"
.Sh DESCRIPTION
This call flushes any dirty file system buffers for the file.
It is used to implement the
.Fn VOP_FSYNC
ensures that a file can be recovered to its current state following a crash.
That typically requires flushing the file's dirty buffers, its inode, and
possibly other filesystem metadata to persistent media.
.Fn VOP_FSYNC
is used to implement the
.Xr sync 2
and
.Xr fsync 2
@ -65,8 +72,20 @@ Push data not written by file system syncer.
.It Fa td
The calling thread.
.El
.Pp
.Fn VOP_FDATASYNC
is similar, but it does not require that all of the file's metadata be flushed.
It only requires that the file's data be recoverable after a crash.
That implies that the data itself must be flushed to disk, as well as some
metadata such as the file's size but not necessarily its attributes.
.Fn VOP_FDATASYNC
should always wait for I/O to complete, as if called with
.Dv MNT_WAIT .
.Fn VOP_FDATASYNC
is used to implement
.Xr fdatasync 2 .
.Sh LOCKS
The file should be locked on entry.
The vnode should be exclusively locked on entry, and stays locked on return.
.Sh RETURN VALUES
Zero is returned if the call is successful, otherwise an appropriate
error code is returned.