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diff --git a/static/openbsd/man9/VOP_LOOKUP.9 b/static/openbsd/man9/VOP_LOOKUP.9 new file mode 100644 index 00000000..e6f17c7c --- /dev/null +++ b/static/openbsd/man9/VOP_LOOKUP.9 @@ -0,0 +1,917 @@ +.\" $OpenBSD: VOP_LOOKUP.9,v 1.46 2022/06/26 05:20:42 visa Exp $ +.\" +.\" Copyright (c) 2003 Ted Unangst +.\" Copyright (c) 2000, 2001 The NetBSD Foundation, Inc. +.\" 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, this list of conditions and the following disclaimer. +.\" 2. Redistributions in binary form must reproduce the above copyright +.\" notice, 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 AUTHOR ``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 AUTHOR 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. +.\" +.Dd $Mdocdate: June 26 2022 $ +.Dt VOP_LOOKUP 9 +.Os +.Sh NAME +.Nm VOP_LOOKUP , +.Nm VOP_ABORTOP , +.Nm VOP_ACCESS , +.Nm VOP_ADVLOCK , +.Nm VOP_BMAP , +.Nm VOP_BWRITE , +.Nm VOP_CLOSE , +.Nm VOP_CREATE , +.Nm VOP_FSYNC , +.Nm VOP_GETATTR , +.Nm VOP_INACTIVE , +.Nm VOP_IOCTL , +.Nm VOP_ISLOCKED , +.Nm VOP_KQFILTER , +.Nm VOP_LINK , +.Nm VOP_LOCK , +.Nm VOP_MKDIR , +.Nm VOP_MKNOD , +.Nm VOP_OPEN , +.Nm VOP_PATHCONF , +.Nm VOP_PRINT , +.Nm VOP_READ , +.Nm VOP_READDIR , +.Nm VOP_READLINK , +.Nm VOP_RECLAIM , +.Nm VOP_REMOVE , +.Nm VOP_RENAME , +.Nm VOP_REVOKE , +.Nm VOP_RMDIR , +.Nm VOP_SETATTR , +.Nm VOP_STRATEGY , +.Nm VOP_SYMLINK , +.Nm VOP_UNLOCK , +.Nm VOP_WRITE +.Nd vnode operations +.Sh SYNOPSIS +.In sys/vnode.h +.Ft int +.Fo VOP_ABORTOP +.Fa "struct vnode *dvp" +.Fa "struct componentname *cnp" +.Fc +.Ft int +.Fo VOP_ACCESS +.Fa "struct vnode *vp" +.Fa "int mode" +.Fa "struct ucred *cred" +.Fa "struct proc *p" +.Fc +.Ft int +.Fo VOP_ADVLOCK +.Fa "struct vnode *vp" +.Fa "void *id" +.Fa "int op" +.Fa "struct flock *fl" +.Fa "int flags" +.Fc +.Ft int +.Fo VOP_BMAP +.Fa "struct vnode *vp" +.Fa "daddr_t bn" +.Fa "struct vnode **vpp" +.Fa "daddr_t *bnp" +.Fa "int *runp" +.Fc +.Ft int +.Fo VOP_BWRITE +.Fa "struct buf *bp" +.Fc +.Ft int +.Fo VOP_CLOSE +.Fa "struct vnode *vp" +.Fa "int fflag" +.Fa "struct ucred *cred" +.Fa "struct proc *p" +.Fc +.Ft int +.Fo VOP_CREATE +.Fa "struct vnode *dvp" +.Fa "struct vnode **vpp" +.Fa "struct componentname *cnp" +.Fa "struct vattr *vap" +.Fc +.Ft int +.Fo VOP_FSYNC +.Fa "struct vnode *vp" +.Fa "struct ucred *cred" +.Fa "int waitfor" +.Fa "struct proc *p" +.Fc +.Ft int +.Fo VOP_GETATTR +.Fa "struct vnode *vp" +.Fa "struct vattr *vap" +.Fa "struct ucred *cred" +.Fa "struct proc *p" +.Fc +.Ft int +.Fo VOP_INACTIVE +.Fa "struct vnode *vp" +.Fa "struct proc *p" +.Fc +.Ft int +.Fo VOP_IOCTL +.Fa "struct vnode *vp" +.Fa "u_long command" +.Fa "void *data" +.Fa "int fflag" +.Fa "struct ucred *cred" +.Fa "struct proc *p" +.Fc +.Ft int +.Fo VOP_ISLOCKED +.Fa "struct vnode *vp" +.Fc +.Ft int +.Fo VOP_KQFILTER +.Fa "struct vnode *vp" +.Fa "struct knote *kn" +.Fc +.Ft int +.Fo VOP_LINK +.Fa "struct vnode *dvp" +.Fa "struct vnode *vp" +.Fa "struct componentname *cnp" +.Fc +.Ft int +.Fo VOP_LOCK +.Fa "struct vnode *vp" +.Fa "int flags" +.Fc +.Ft int +.Fo VOP_LOOKUP +.Fa "struct vnode *dvp" +.Fa "struct vnode **vpp" +.Fa "struct componentname *cnp" +.Fc +.Ft int +.Fo VOP_MKDIR +.Fa "struct vnode *dvp" +.Fa "struct vnode **vpp" +.Fa "struct componentname *cnp" +.Fa "struct vattr *vap" +.Fc +.Ft int +.Fo VOP_MKNOD +.Fa "struct vnode *dvp" +.Fa "struct vnode **vpp" +.Fa "struct componentname *cnp" +.Fa "struct vattr *vap" +.Fc +.Ft int +.Fo VOP_OPEN +.Fa "struct vnode *vp" +.Fa "int mode" +.Fa "struct ucred *cred" +.Fa "struct proc *p" +.Fc +.Ft int +.Fo VOP_PATHCONF +.Fa "struct vnode *vp" +.Fa "int name" +.Fa "register_t *retval" +.Fc +.Ft int +.Fo VOP_PRINT +.Fa "struct vnode *vp" +.Fc +.Ft int +.Fo VOP_READ +.Fa "struct vnode *vp" +.Fa "struct uio *uio" +.Fa "int ioflag" +.Fa "struct ucred *cred" +.Fc +.Ft int +.Fo VOP_READDIR +.Fa "struct vnode *vp" +.Fa "struct uio *uio" +.Fa "struct ucred *cred" +.Fa "int *eofflag" +.Fc +.Ft int +.Fo VOP_READLINK +.Fa "struct vnode *vp" +.Fa "struct uio *uio" +.Fa "struct ucred *cred" +.Fc +.Ft int +.Fo VOP_RECLAIM +.Fa "struct vnode *vp" +.Fa "struct proc *p" +.Fc +.Ft int +.Fo VOP_REMOVE +.Fa "struct vnode *dvp" +.Fa "struct vnode *vp" +.Fa "struct componentname *cnp" +.Fc +.Ft int +.Fo VOP_RENAME +.Fa "struct vnode *fdvp" +.Fa "struct vnode *fvp" +.Fa "struct componentname *fcnp" +.Fa "struct vnode *tdvp" +.Fa "struct vnode *tvp" +.Fa "struct componentname *tcnp" +.Fc +.Ft int +.Fo VOP_REVOKE +.Fa "struct vnode *vp" +.Fa "int flags" +.Fc +.Ft int +.Fo VOP_RMDIR +.Fa "struct vnode *dvp" +.Fa "struct vnode *vp" +.Fa "struct componentname *cnp" +.Fc +.Ft int +.Fo VOP_SETATTR +.Fa "struct vnode *vp" +.Fa "struct vattr *vap" +.Fa "struct ucred *cred" +.Fa "struct proc *p" +.Fc +.Ft int +.Fo VOP_STRATEGY +.Fa "struct vnode *vp" +.Fa "struct buf *bp" +.Fc +.Ft int +.Fo VOP_SYMLINK +.Fa "struct vnode *dvp" +.Fa "struct vnode **vpp" +.Fa "struct componentname *cnp" +.Fa "struct vattr *vap" +.Fa "char *target" +.Fc +.Ft int +.Fo VOP_UNLOCK +.Fa "struct vnode *vp" +.Fc +.Ft int +.Fo VOP_WRITE +.Fa "struct vnode *vp" +.Fa "struct uio *uio" +.Fa "int ioflag" +.Fa "struct ucred *cred" +.Fc +.Sh DESCRIPTION +The +.Nm VOP +functions implement a generic way to perform operations on vnodes. +The VOP function called passes the arguments to the correct file system +specific function. +Not all file systems implement all operations, in which case a generic +method will be used. +These functions exist to provide an abstract method to invoke vnode +operations without needing to know anything about the underlying file system. +Many system calls map directly to a specific VOP function. +.Pp +The arguments for each VOP +function consist of one or more vnode pointers along with other data +needed to perform the operation. +Care must be taken to obey the vnode locking discipline when using +VOP functions. +Many VOP calls take a +.Vt struct proc *p +argument. +This should be the current process. +VOP calls are not safe to call in an interrupt context. +.Pp +The +.Vt vattr +structure used by +.Fn VOP_CREATE , +.Fn VOP_GETATTR , +.Fn VOP_MKDIR , +.Fn VOP_MKNOD , +.Fn VOP_SETATTR , +and +.Fn VOP_SYMLINK +is: +.Bd -literal +struct vattr { + enum vtype va_type; /* vnode type */ + mode_t va_mode; /* files access mode and type */ + nlink_t va_nlink; /* number of references */ + uid_t va_uid; /* owner user id */ + gid_t va_gid; /* owner group id */ + long va_fsid; /* file system id */ + u_quad_t va_fileid; /* file id */ + u_quad_t va_size; /* file size in bytes */ + long va_blocksize; /* blocksize preferred for i/o */ + struct timespec va_atime; /* time of last access */ + struct timespec va_mtime; /* time of last modification */ + struct timespec va_ctime; /* time file changed */ + u_long va_gen; /* generation number of file */ + u_long va_flags; /* flags defined for file */ + dev_t va_rdev; /* device the vnode represents */ + u_quad_t va_bytes; /* bytes of held disk space */ + u_quad_t va_filerev; /* file modification number */ + u_int va_vaflags; /* operations flags */ + long va_spare; /* remain quad aligned */ +}; +.Ed +.Pp +The following sections comment on the VOP functions from the consumer's +perspective. +.Pp +.Bl -tag -width Ds -compact +.It Fn VOP_ABORTOP dvp cnp +Abort any asynchronous operations pending on the vnode +.Fa dvp +associated with the path name +.Fa cnp . +This is mostly used by internal VFS code and should not be needed by +file system implementors. +.Pp +.It Fn VOP_ACCESS vp mode cred p +Determine if the locked vnode +.Fa vp +can be accessed by the calling process +.Fa p +with credentials +.Fa cred +for the given access +.Fa mode . +.Pp +.Fa mode +may contain any of the following values: +.Pp +.Bl -tag -width Ds -compact -offset indent +.It Dv VWRITE +check writeability +.It Dv VREAD +check readability +.It Dv VEXEC +check executability +.El +.Pp +If the access check succeeds, zero is returned; otherwise, an +appropriate error code is returned. +.Pp +.It Fn VOP_ADVLOCK vp id op fl flags +Perform advisory locking on the vnode +.Fa vp +according to the operation +.Fa op +and lock specification +.Fa fl . +.Fa id +identifies the resource holding the lock +(typically a pointer to the holding process). +.Pp +.Fa op +may be one of the following operations: +.Pp +.Bl -tag -width F_GETLK -compact -offset indent +.It Dv F_GETLK +Get the first lock that would block a lock request. +.It Dv F_SETLK +Set a lock. +.It Dv F_UNLCK +Release a lock. +.El +.Pp +.Fa flags +may contain the following flags: +.Pp +.Bl -tag -width F_POSIX -compact -offset indent +.It Dv F_WAIT +If required, block waiting to obtain an exclusive lock. +.It Dv F_POSIX +Follow POSIX locking semantics; see +.Xr fcntl 2 . +.It Dv F_FLOCK +Follow +.Xr flock 2 +locking semantics. +.El +.Pp +Upon success, zero is returned; otherwise, an appropriate error code is +returned. +.Pp +.It Fn VOP_BMAP vp bn vpp bnp runp +Convert the logical block number +.Fa bn +of the file the locked vnode +.Fa vp +is associated with its physical number on-disk. +The physical block number is stored in +.Fa *bnp +on return. +.Fa vpp , +if +.No non- Ns Dv NULL , +will be updated to point to the vnode of the block device of which +.Fa vp +is associated. +.Fa runp , +if +.No non- Ns Dv NULL , +will be updated to the number of contiguous disk blocks following +.Fa *bnp . +Upon success, zero is returned; otherwise, an appropriate error code is +returned. +.Pp +.It Fn VOP_BWRITE bp +Write a file system buffer to disk. +Upon success, zero is returned; otherwise, an appropriate error code is +returned. +.Pp +.It Fn VOP_CLOSE vp fflag cred p +Close the file associated with the locked vnode +.Fa vp +with file flags +.Fa fflag +by the calling process +.Fa p +with credentials +.Fa cred . +This operation should be performed only when the file is no longer being +used. +Upon success, zero is returned; otherwise, an appropriate error code is +returned. +.Pp +.It Fn VOP_CREATE dvp vpp cnp vap +Create a new directory entry for a regular file in the directory +.Fa dvp +and return a locked, referenced vnode in +.Fa vpp . +The file name is in +.Fa cnp +and its permissions will be +.Fa vap . +.Fa dvp +must be locked. +.Pp +.It Fn VOP_FSYNC vp cred waitfor p +Flush any dirty buffers associated with +.Fa vp +to disk. +The vnode is locked on entry and exit. +.Fa waitfor +can be set to +.Dv MNT_WAIT +to indicate that +.Fn VOP_FSYNC +should not return until all data is written. +.Pp +.It Fn VOP_GETATTR vp vap cred p +.It Fn VOP_SETATTR vp vap cred p +Access the vnode attributes +.Fa vap +of the vnode +.Fa vp +by the calling process +.Fa p +with credentials +.Fa cred . +.Fn VOP_SETATTR +requires that +.Fa vp +be locked. +A field value for any member of +.Fa vap +of +.Dv VNOVAL +represents that the information could not be obtained by +.Fn VOP_GETATTR +or should not be changed by +.Fn VOP_SETATTR . +Upon success of obtaining or changing the attributes, zero is returned; +otherwise, an appropriate error code is returned. +All attributes are held in the +.Vt vattr +structure shown above. +.Pp +.It Fn VOP_INACTIVE vp p +Notify the underlying file system that the locked vnode +.Fa vp +is no longer in use. +The vnode will be unlocked upon return. +.Fa p +specifies the calling process. +This may happen when the vnode reference count reaches zero or +when the underlying file system has disappeared or has been forcibly +unmounted. +.Pp +Typically, the underlying file system will write any buffers associated +with +.Fa vp +to disk or delete the file entry, if need be. +The underlying file system may not necessarily release any buffers +associated with +.Fa vp +so that it can be immediately reactivated in case the file is used again. +Upon success, zero is returned; otherwise, an appropriate error code is +returned. +.Pp +.It Fn VOP_IOCTL vp command data fflag cred p +Perform the control operation +.Fa command +with additional information +.Fa data +on the vnode +.Fa vp , +normally associated with a device, +with file flags +.Fa fflag +by the calling process +.Fa p +with credentials +.Fa cred . +Upon success, zero is returned; otherwise, an appropriate error code is +returned. +.Pp +.It Fn VOP_ISLOCKED vp +.It Fn VOP_LOCK vp flags +.It Fn VOP_UNLOCK vp +.Fn VOP_LOCK +is used internally by +.Xr vn_lock 9 +to lock a vnode. +It should not be used by other file system code. +.Fn VOP_UNLOCK +unlocks a vnode. +Note the asymmetry between +.Xr vn_lock 9 +and +.Fn VOP_UNLOCK . +.Pp +.Fa flags +may contain the following flags: +.Pp +.Bl -tag -width LK_RECURSEFAIL -compact -offset indent +.It Dv LK_EXCLUSIVE +Acquire an exclusive lock. +.It Dv LK_SHARED +Acquire a shared lock. +.It Dv LK_NOWAIT +Don't wait if the vnode lock is held by someone else +(may still wait on reclamation lock). +.It Dv LK_RECURSEFAIL +Attempt at recursive lock fails. +.It Dv LK_DRAIN +Used to mean something else, but is now used abused as a flag to avoid a lock +inversion deadlock in deadfs. +Do not use this, it must die. +.El +.Pp +.Fn VOP_ISLOCKED +returns one of the following values: +.Pp +.Bl -tag -width LK_EXCLUSIVE -compact -offset indent +.It Dv LK_EXCLUSIVE +.Fa vp +is locked for exclusive access by the calling thread. +.It Dv LK_EXCLOTHER +.Fa vp +is locked for exclusive access by a different thread. +.It Dv LK_SHARED +.Fa vp +is locked for shared access. +The current thread may be one of the threads that have it locked. +.It 0 +.Fa vp +is not locked. +.El +.Pp +.Fn VOP_ISLOCKED +should be used cautiously, as not all file systems implement locks +effectively. +.Pp +.It Fn VOP_KQFILTER vp kn +Register the +.Xr knote 9 +filtering information +.Fa kn +for the vnode +.Fa vp . +Only filters for +.Dv EVFILT_READ , +.Dv EVFILT_WRITE , +and +.Dv EVFILT_VNODE +will invoke this operation. +Upon success, zero is returned; otherwise, a non-zero value is returned. +.Pp +.It Fn VOP_LINK dvp vp cnp +Increase the link count for the vnode +.Fa vp . +A new entry with name +.Fa cnp +should be added to the directory +.Fa dvp . +.Fa dvp +is locked on entry and unlocked on exit. +.Pp +.It Fn VOP_LOOKUP dvp vpp cnp +Find the file corresponding to the name +.Fa cnp +in the directory +.Fa dvp +and return a vnode in +.Fa vpp . +.Fa dvp +must be locked and referenced on entry with +.Xr vget 9 . +On a successful return, +.Fa vpp +will be returned locked and referenced, and +.Fa dvp +will return with the same reference count, but may be returned locked +or unlocked depending on the specific flags used in +.Fa cnp->cn_flags . +On error +.Fa vpp +will be +.Dv NULL +and +.Fa cnp->cn_flags +will be set to +.Dv PDIRUNLOCK +if +.Fa dvp +has been unlocked. +.Pp +.It Fn VOP_MKDIR dvp vpp cnp vap +Create a new directory named by +.Fa cnp +with permissions +.Fa vattr +in the directory +.Fa dvp . +On success, the new vnode is returned locked in +.Fa vpp . +.Fa dvp +must be locked on entry and is unlocked on exit. +.Pp +.It Fn VOP_MKNOD dvp vpp cnp vap +Create a device special file with name +.Fa cnp +and attributes +.Fa vap +in the directory associated with the locked vnode +.Fa dvp . +A pointer to the new, locked vnode will be returned in +.Fa *vpp +if +.Fa vpp +is not +.Dv NULL . +Upon success, zero is returned; otherwise, an appropriate error code is +returned. +.Pp +.It Fn VOP_OPEN vp mode cred p +Open the file associated with the vnode +.Fa vp +with the access modes +.Fa mode +by the calling process +.Fa p +with credentials +.Fa cred . +.Fa mode +takes the flags described in +.Xr open 2 . +.Pp +For some underlying file systems, access permissions for the file by the +process are checked; for others, this is a no-op. +In any case, this must be called before a process can access the file. +Upon success, zero is returned; otherwise, an appropriate error code is +returned. +.Pp +.It Fn VOP_PATHCONF vp name retval +Obtain the value of the applicable POSIX configurable pathname variable (see +.Xr pathconf 2 ) +specified by +.Fa name +from the locked vnode +.Fa vp . +The result is placed in +.Fa *retval . +Upon success, zero is returned; otherwise, an appropriate error code is +returned. +.Pp +.It Fn VOP_PRINT vp +Print information about the vnode to the kernel message buffer. +It is not used normally, but exists only for debugging purposes. +.Pp +.It Fn VOP_READ vp uio ioflag cred +Copy data from the locked vnode +.Fa vp +to the buffers specified by +.Fa uio +with calling process credentials +.Fa cred . +.Pp +.Fa ioflag +may contain the following flags: +.Pp +.Bl -tag -width IO_APPEND -offset indent -compact +.It Dv IO_NDELAY +Non-blocking I/O. +.It Dv IO_UNIT +Do I/O as an atomic unit. +.El +.Pp +Upon success, zero is returned; otherwise, an appropriate error code is +returned. +.Pp +.It Fn VOP_READDIR vp uio cred eofflag +Read the contents of the directory associated with the locked vnode +.Fa vp , +usually via +.Fn VOP_READ , +and convert its file-system-specific format to that expected by the +.Xr getdents 2 +system call, storing the result into the buffers specified by +.Fa uio . +.Fa cred +specifies the credentials of the calling process. +.Fa *eofflag +is set to a non-zero value on return once successful end-of-file for the +directory contents has been reached. +.Pp +Upon success, zero is returned; otherwise, an appropriate error code is +returned. +.Pp +.It Fn VOP_READLINK vp uio cred +Read a symbolic link and return the target's name in +.Fa uio . +.Fa vp +is locked on entry and exit and must be a symlink. +.Pp +.It Fn VOP_RECLAIM vp p +Used by +.Xr vclean 9 +so that the file system has an opportunity to free memory +and perform any other cleanup activity related to +.Fa vp . +.Fa vp +is unlocked on entry and exit. +.Fn VOP_RECLAIM +should not be used by generic code. +.Pp +.It Fn VOP_REMOVE dvp vp cnp +Remove the link named +.Fa cnp +from the directory +.Fa dvp . +This file corresponds to the vnode +.Fa vp . +Both +.Fa dvp +and +.Fa vp +are locked on entry and unlocked on exit, and +each has its reference count decremented by one. +.Fn VOP_REMOVE +does not delete the file from disk unless its link count +becomes zero (for file systems which support multiple links). +.Pp +.It Fn VOP_RENAME fdvp fvp fcnp tdvp tvp tcnp +Remove the link to the file with associated vnode +.Fa fvp +and name +.Fa fcnp +in the directory with associated vnode +.Fa fdvp , +and create a new link to the file with name +.Fa tcnp +(and associated locked vnode +.Fa tvp , +if the file already exists) residing in the directory with the +associated locked vnode +.Fa tdvp . +.Fa fdvp , +.Fa fvp , +and +.Fa tvp +(if not +.Dv NULL ) +will be released (see +.Xr vrele 9 ) +and +.Fa tdvp +will have its reference count decremented (see +.Xr vput 9 ) +on return. +If not +.Dv NULL , +.Fa tvp +will be unlocked on return (see +.Xr vput 9 ) . +Upon success, zero is returned; otherwise, an appropriate error code is +returned. +.Pp +.It Fn VOP_REVOKE vp flags +Used by the +.Xr revoke 2 +system call to prevent any further access to a vnode. +The vnode ops will be changed to those of deadfs, which returns only +errors. +.Ar vp +must be unlocked. +.Pp +.It Fn VOP_RMDIR dvp vp cnp +Remove the directory +.Fa vp +from the directory +.Fa dvp . +Both are locked on entry and unlocked on exit. +The name of the directory for removal is additionally contained in +.Fa cnp . +.Pp +.It Fn VOP_STRATEGY vp bp +Call the appropriate strategy function for the device vnode +.Fa vp +to read or write the buffer +.Fa bp . +.Pp +.It Fn VOP_SYMLINK dvp vpp cnp vap target +Create a symbolic link with name +.Fa cnp +in the directory +.Fa dvp +with mode +.Fa vap . +The link will point to +.Fa target +and a vnode for it is returned in +.Fa vpp . +The directory vnode is locked on entry and unlocked on exit. +Note that unlike most VOP calls returning a vnode, +.Fn VOP_SYMLINK +does not lock or reference +.Fa vpp . +.Pp +.It Fn VOP_WRITE vp uio ioflag cred +Copy data from the buffers specified by +.Fa uio +to the locked vnode +.Fa vp +with calling process credentials +.Fa cred . +.Pp +.Fa ioflag +may contain the following flags: +.Pp +.Bl -tag -width IO_APPEND -offset indent -compact +.It Dv IO_APPEND +Perform write at the end of file. +.It Dv IO_NDELAY +Non-blocking I/O. +.It Dv IO_SYNC +Wait for I/O to complete. +.It Dv IO_UNIT +Do I/O as an atomic unit. +.El +.Pp +Upon success, zero is returned; otherwise, an appropriate error code is +returned. +.El +.Sh RETURN VALUES +The +.Nm VOP +functions return 0 to indicate success and a non-zero error code +to indicate failure. +.Sh SEE ALSO +.Xr errno 2 , +.Xr uiomove 9 , +.Xr vfs 9 , +.Xr vn_lock 9 , +.Xr vnode 9 +.Sh AUTHORS +This man page was written by +.An Ted Unangst +for +.Ox . +.Sh BUGS +The locking discipline is too complex. +Refer to +.Xr vn_lock 9 . |