vnode_if.h

Overview

Use the links in the table of contents to the left to access the documentation.

Functions

VNOP_BWRITE

Write a buffer to backing store.

VNOP_FSYNC

Call down to a filesystem to synchronize a file with on-disk state.

VNOP_GETXATTR

Get extended file attributes.

VNOP_IOCTL

Call down to a filesystem or device driver to execute various control operations on or request data about a file.

VNOP_READ

Call down to a filesystem to read file data.

VNOP_SETXATTR

Set extended file attributes.

VNOP_STRATEGY

Initiate I/O on a file (both read and write).

VNOP_WRITE

Call down to the filesystem to write file data.

Write a buffer to backing store.

extern errno_t VNOP_BWRITE(
    buf_t);  

Parameters

Return Value

0 for success, else an error code.

Discussion

VNOP_BWRITE() is called by buf_bawrite() (asynchronous write) and potentially by buf_bdwrite() (delayed write) but not by buf_bwrite(). A filesystem may choose to perform some kind of manipulation of the buffer in this routine; it generally will end up calling VFS's default implementation, vn_bwrite() (which calls buf_bwrite() without further ado).

Call down to a filesystem to synchronize a file with on-disk state.

extern errno_t VNOP_FSYNC(
    vnode_t,
    int,
    vfs_context_t);  

Parameters

Return Value

0 for success, else an error code.

Discussion

VNOP_FSYNC is called whenever we need to make sure that a file's data has been pushed to backing store, for example when recycling; it is also the heart of the fsync() system call.

Get extended file attributes.

extern errno_t VNOP_GETXATTR(
    vnode_t,
    const char *,
    uio_t,
    size_t *,
    int,
    vfs_context_t);  

Parameters

Return Value

0 for success, or an error code.

Call down to a filesystem or device driver to execute various control operations on or request data about a file.

extern errno_t VNOP_IOCTL(
    vnode_t,
    u_long,
    caddr_t,
    int,
    vfs_context_t);  

Parameters

Return Value

0 for success or a filesystem-specific error.

Discussion

Ioctl controls are typically associated with devices, but they can in fact be passed down for any file; they are used to implement any of a wide range of controls and information requests. fcntl() calls VNOP_IOCTL for several commands, and will attempt a VNOP_IOCTL if it is passed an unknown command, though no copyin or copyout of arguments can occur in this case--the "arg" must be an integer value. Filesystems can define their own fcntls using this mechanism. How ioctl commands are structured is slightly complicated; see the manual page for ioctl(2).

Call down to a filesystem to read file data.

extern errno_t VNOP_READ(
    vnode_t,
    struct uio *,
    int,
    vfs_context_t);  

Parameters

Return Value

0 for success or a filesystem-specific error. VNOP_READ() can return success even if less data was read than originally requested; returning an error value should indicate that something actually went wrong.

Discussion

VNOP_READ() is where the hard work of of the read() system call happens. The filesystem may use the buffer cache, the cluster layer, or an alternative method to get its data; uio routines will be used to see that data is copied to the correct virtual address in the correct address space and will update its uio argument to indicate how much data has been moved. Filesystems will not receive a read request on a file without having first received a VNOP_OPEN().

Set extended file attributes.

extern errno_t VNOP_SETXATTR(
    vnode_t,
    const char *,
    uio_t,
    int,
    vfs_context_t);  

Parameters

Return Value

0 for success, or an error code.

Initiate I/O on a file (both read and write).

extern errno_t VNOP_STRATEGY(
    struct buf *bp);  

Parameters

Return Value

0 for success, else an error code.

Discussion

A filesystem strategy routine takes a buffer, performs whatever manipulations are necessary for passing the I/O request down to the device layer, and calls the appropriate device's strategy routine. Most filesystems should just call buf_strategy() with "bp" as the argument.

Call down to the filesystem to write file data.

extern errno_t VNOP_WRITE(
    vnode_t,
    struct uio *,
    int,
    vfs_context_t);  

Parameters

Return Value

0 for success or a filesystem-specific error. VNOP_WRITE() can return success even if less data was written than originally requested; returning an error value should indicate that something actually went wrong.

Discussion

VNOP_WRITE() is to write() as VNOP_READ() is to read(). The filesystem may use the buffer cache, the cluster layer, or an alternative method to write its data; uio routines will be used to see that data is copied to the correct virtual address in the correct address space and will update its uio argument to indicate how much data has been moved. Filesystems will not receive a write request on a file without having first received a VNOP_OPEN().

Structs and Unions

vnop_access_args

Call down to a filesystem to close a file.

vnop_advlock_args

Query a filesystem for path properties.

vnop_allocate_args

Aquire or release and advisory lock on a vnode.

vnop_blktooff_args

List extended attribute keys.

vnop_blockmap_args

Call down to a filesystem to convert a file offset to a logical block number.

vnop_close_args

Call down to a filesystem to open a file.

vnop_copyfile_args

Write data from a mapped file back to disk.

vnop_create_args

Call down to a filesystem to look for a directory entry by name.

vnop_exchange_args

Call down to a filesystem or device to check if a file is ready for I/O and request later notification if it is not currently ready.

vnop_fsync_args

Inform a filesystem that a file is no longer mapped.

vnop_getattr_args

Call down to a filesystem to see if a kauth-style operation is permitted.

vnop_getnamedstream_args

Associate a MACF label with a file.

vnop_getxattr_args

Write data from a mapped file back to disk.

vnop_inactive_args

Call down to a filesystem to get the pathname represented by a symbolic link.

vnop_link_args

Call down to a filesystem to delete a file.

vnop_listxattr_args

Remove extended file attributes.

vnop_makenamedstream_args

Get a named stream associated with a file.

vnop_mkdir_args

Call down to a filesystem to rename a file.

vnop_mknod_args

Call down to a filesystem to create a whiteout.

vnop_mmap_args

Call down to a filesystem to invalidate all open file descriptors for a vnode.

vnop_mnomap_args

Notify a filesystem that a file is being mmap-ed.

vnop_offtoblk_args

Call down to a filesystem to convert a logical block number to a file offset.

vnop_open_args

Call down to a filesystem to create a special file.

vnop_pagein_args

Pre-allocate space for a file.

vnop_pageout_args

Pull file data into memory.

vnop_pathconf_args

Release filesystem-internal resources for a vnode.

vnop_read_args

Call down to a filesystem to set vnode attributes.

vnop_readdir_args

Call down to a filesystem to create a symbolic link.

vnop_readdirattr_args

Call down to a filesystem to enumerate directory entries.

vnop_readlink_args

Call down to get file attributes for many files in a directory at once.

vnop_reclaim_args

Notify a filesystem that the last usecount (persistent reference) on a vnode has been dropped.

vnop_removenamedstream_args

Create a named stream associated with a file.

vnop_rename_args

Call down to a filesystem to create a hardlink to a file.

vnop_revoke_args

Call down to a filesystem to atomically exchange the data of two files.

vnop_rmdir_args

Call down to a filesystem to create a directory.

vnop_searchfs_args

Write data from a mapped file back to disk.

vnop_setattr_args

Call down to a filesystem to get vnode attributes.

VNOP_SETLABEL

Associate a MACF label with a file.

vnop_strategy_args

Call down to a filesystem to get information about the on-disk layout of a file region.

vnop_symlink_args

Call down to a filesystem to delete a directory.

vnop_whiteout_args

Call down to a filesystem to create a regular file (VREG).

Call down to a filesystem to close a file.

struct vnop_access_args { 
    struct vnodeop_desc *a_desc; 
    vnode_t a_vp; 
    int a_action; 
    vfs_context_t a_context; 
};  

Fields

Discussion

The close vnop gives a filesystem a chance to release state set up by a VNOP_OPEN(). VFS promises to send down exactly one VNOP_CLOSE() for each VNOP_OPEN().

Query a filesystem for path properties.

struct vnop_advlock_args { 
    struct vnodeop_desc *a_desc; 
    vnode_t a_vp; 
    caddr_t a_id; 
    int a_op; 
    struct flock *a_fl; 
    int a_flags; 
    vfs_context_t a_context; 
};  

Fields

Aquire or release and advisory lock on a vnode.

struct vnop_allocate_args { 
    struct vnodeop_desc *a_desc; 
    vnode_t a_vp; 
    off_t a_length; 
    u_int32_t a_flags; 
    off_t *a_bytesallocated; 
    off_t a_offset; 
    vfs_context_t a_context; 
};  

Fields

Discussion

Advisory locking is somewhat complicated. VNOP_ADVLOCK is overloaded for both flock() and POSIX advisory locking usage, though not all filesystems support both (or any). VFS provides an advisory locking mechanism for filesystems which can take advantage of it; vfs_setlocklocal() marks a filesystem as using VFS advisory locking support.

List extended attribute keys.

struct vnop_blktooff_args { 
    struct vnodeop_desc *a_desc; 
    vnode_t a_vp; 
    daddr64_t a_lblkno; 
    off_t *a_offset; 
};  

Fields

Discussion

Should write a sequence of unseparated, null-terminated extended-attribute names into the space described by the provided uio. These keys can then be passed to getxattr() (and VNOP_GETXATTR()).

Call down to a filesystem to convert a file offset to a logical block number.

struct vnop_blockmap_args { 
    struct vnodeop_desc *a_desc; 
    vnode_t a_vp; 
    off_t a_foffset; 
    size_t a_size; 
    daddr64_t *a_bpn; 
    size_t *a_run; 
    void *a_poff; 
    int a_flags; 
    vfs_context_t a_context; 
};  

Fields

Call down to a filesystem to open a file.

struct vnop_close_args { 
    struct vnodeop_desc *a_desc; 
    vnode_t a_vp; 
    int a_fflag; 
    vfs_context_t a_context; 
};  

Fields

Discussion

The open vnop gives a filesystem a chance to initialize a file for operations like reading, writing, and ioctls. VFS promises to send down exactly one VNOP_CLOSE() for each VNOP_OPEN().

Write data from a mapped file back to disk.

struct vnop_copyfile_args { 
    struct vnodeop_desc *a_desc; 
    vnode_t a_fvp; 
    vnode_t a_tdvp; 
    vnode_t a_tvp; 
    struct componentname *a_tcnp; 
    int a_mode; 
    int a_flags; 
    vfs_context_t a_context; 
};  

Fields

Discussion

VNOP_PAGEOUT() is called when data from a mapped file needs to be flushed to disk, either because of an msync() call or due to memory pressure. Filesystems are for the most part expected to just call cluster_pageout().

Call down to a filesystem to look for a directory entry by name.

struct vnop_create_args { 
    struct vnodeop_desc *a_desc; 
    vnode_t a_dvp; 
    vnode_t *a_vpp; 
    struct componentname *a_cnp; 
    struct vnode_attr *a_vap; 
    vfs_context_t a_context; 
};  

Fields

Discussion

VNOP_LOOKUP is the key pathway through which VFS asks a filesystem to find a file. The vnode should be returned with an iocount to be dropped by the caller. A VNOP_LOOKUP() calldown can come without a preceding VNOP_OPEN().

Call down to a filesystem or device to check if a file is ready for I/O and request later notification if it is not currently ready.

struct vnop_exchange_args { 
    struct vnodeop_desc *a_desc; 
    vnode_t a_fvp; 
    vnode_t a_tvp; 
    int a_options; 
    vfs_context_t a_context; 
};  

Fields

Discussion

In general, regular are always "ready for I/O" and their select vnops simply return "1." Devices, though, may or may not be read; they keep track of who is selecting on them and send notifications when they become ready. xnu provides structures and routines for tracking threads waiting for I/O and waking up those threads: see selrecord(), selthreadclear(), seltrue(), selwait(), selwakeup(), and the selinfo structure (sys/select.h).

Inform a filesystem that a file is no longer mapped.

struct vnop_fsync_args { 
    struct vnodeop_desc *a_desc; 
    vnode_t a_vp; 
    int a_waitfor; 
    vfs_context_t a_context; 
};  

Fields

Discussion

In general, no action is required of a filesystem for VNOP_MNOMAP.

Call down to a filesystem to see if a kauth-style operation is permitted.

struct vnop_getattr_args { 
    struct vnodeop_desc *a_desc; 
    vnode_t a_vp; 
    struct vnode_attr *a_vap; 
    vfs_context_t a_context; 
};  

Fields

Discussion

VNOP_ACCESS is currently only called on filesystems which mark themselves as doing their authentication remotely (vfs_setauthopaque(), vfs_authopaque()). A VNOP_ACCESS() calldown may come without any preceding VNOP_OPEN().

Associate a MACF label with a file.

struct vnop_getnamedstream_args { 
    struct vnodeop_desc *a_desc; 
    vnode_t a_vp; 
    vnode_t *a_svpp; 
    const char *a_name; 
    enum nsoperation a_operation; int a_flags; vfs_context_t a_context; 
};  

Fields

Write data from a mapped file back to disk.

struct vnop_getxattr_args { 
    struct vnodeop_desc *a_desc; 
    vnode_t a_vp; 
    const char * a_name; 
    uio_t a_uio; 
    size_t *a_size; 
    int a_options; 
    vfs_context_t a_context; 
};  

Fields

Discussion

VNOP_PAGEOUT() is called when data from a mapped file needs to be flushed to disk, either because of an msync() call or due to memory pressure. Filesystems are for the most part expected to just call cluster_pageout().

Call down to a filesystem to get the pathname represented by a symbolic link.

struct vnop_inactive_args { 
    struct vnodeop_desc *a_desc; 
    vnode_t a_vp; 
    vfs_context_t a_context; 
};  

Fields

Discussion

VNOP_READLINK() gets the path stored in a symbolic link; it is called by namei() and the readlink() system call.

Call down to a filesystem to delete a file.

struct vnop_link_args { 
    struct vnodeop_desc *a_desc; 
    vnode_t a_vp; 
    vnode_t a_tdvp; 
    struct componentname *a_cnp; 
    vfs_context_t a_context; 
};  

Fields

Discussion

VNOP_REMOVE is called to remove a file from a filesystem's namespace, for example by unlink(). It can operate on regular files, named pipes, special files, and in some cases on directories.

Remove extended file attributes.

struct vnop_listxattr_args { 
    struct vnodeop_desc *a_desc; 
    vnode_t a_vp; 
    uio_t a_uio; 
    size_t *a_size; 
    int a_options; 
    vfs_context_t a_context; 
};  

Fields

Get a named stream associated with a file.

struct vnop_makenamedstream_args { 
    struct vnodeop_desc *a_desc; 
    vnode_t *a_svpp; 
    vnode_t a_vp; 
    const char *a_name; 
    int a_flags; 
    vfs_context_t a_context; 
};  

Fields

Discussion

If this call sucecss, svpp should be returned with an iocount which the caller will drop. VFS provides a facility for simulating named streams when interacting with filesystems which do not support them.

Call down to a filesystem to rename a file.

struct vnop_mkdir_args { 
    struct vnodeop_desc *a_desc; 
    vnode_t a_dvp; 
    vnode_t *a_vpp; 
    struct componentname *a_cnp; 
    struct vnode_attr *a_vap; 
    vfs_context_t a_context; 
};  

Fields

Discussion

VNOP_RENAME() will only be called with a source and target on the same volume.

Call down to a filesystem to create a whiteout.

struct vnop_mknod_args { 
    struct vnodeop_desc *a_desc; 
    vnode_t a_dvp; 
    vnode_t *a_vpp; 
    struct componentname *a_cnp; 
    struct vnode_attr *a_vap; 
    vfs_context_t a_context; 
};  

Fields

Discussion

Whiteouts are used to support the union filesystem, whereby one filesystem is mounted "transparently" on top of another. A whiteout in the upper layer of a union mount is a "deletion" of a file in the lower layer; lookups will catch the whiteout and fail, setting ISWHITEOUT in the componentname structure, even if an underlying file of the same name exists. The whiteout vnop is used for creation, deletion, and checking whether a directory supports whiteouts (see flags). also support the LOOKUP flag, which is used to test whether a directory supports whiteouts.

Call down to a filesystem to invalidate all open file descriptors for a vnode.

struct vnop_mmap_args { 
    struct vnodeop_desc *a_desc; 
    vnode_t a_vp; 
    int a_fflags; 
    vfs_context_t a_context; 
};  

Fields

Discussion

This function is typically called as part of a TTY revoke, but can also be used on regular files. Most filesystems simply use nop_revoke(), which calls vn_revoke(), as their revoke vnop implementation.

Notify a filesystem that a file is being mmap-ed.

struct vnop_mnomap_args { 
    struct vnodeop_desc *a_desc; 
    vnode_t a_vp; 
    vfs_context_t a_context; 
};  

Fields

Discussion

VNOP_MMAP is an advisory calldown to say that the system is mmap-ing a file.

Call down to a filesystem to convert a logical block number to a file offset.

struct vnop_offtoblk_args { 
    struct vnodeop_desc *a_desc; 
    vnode_t a_vp; 
    off_t a_offset; 
    daddr64_t *a_lblkno; 
};  

Fields

Discussion

VNOP_BLKTOOFF() converts a logical block to a file offset in bytes. That offset can be passed to VNOP_BLOCKMAP(), then, to get a physical block number--buf_strategy() does this.

Call down to a filesystem to create a special file.

struct vnop_open_args { 
    struct vnodeop_desc *a_desc; 
    vnode_t a_vp; 
    int a_mode; 
    vfs_context_t a_context; 
};  

Fields

Discussion

The mknod vnop is used to create character and block device files, named pipe (FIFO) files, and named sockets. The newly created file should be returned with an iocount which will be dropped by the caller. A VNOP_MKNOD() call can come down without a preceding VNOP_OPEN().

Pre-allocate space for a file.

struct vnop_pagein_args { 
    struct vnodeop_desc *a_desc; 
    vnode_t a_vp; 
    upl_t a_pl; 
    upl_offset_t a_pl_offset; 
    off_t a_f_offset; 
    size_t a_size; 
    int a_flags; 
    vfs_context_t a_context; 
};  

Fields

Discussion

VNOP_ALLOCATE() changes the amount of backing store set aside to a file. It can be used to either shrink or grow a file. If the file shrinks, its ubc size will be modified accordingly, but if it grows, then the ubc size is unchanged; space is set aside without being actively used by the file. VNOP_ALLOCATE() is currently only called as part of the F_PREALLOCATE fcntl, and is supported only by AFP and HFS.

Pull file data into memory.

struct vnop_pageout_args { 
    struct vnodeop_desc *a_desc; 
    vnode_t a_vp; 
    upl_t a_pl; 
    upl_offset_t a_pl_offset; 
    off_t a_f_offset; 
    size_t a_size; 
    int a_flags; 
    vfs_context_t a_context; 
};  

Fields

Discussion

VNOP_PAGEIN() is called by when a process faults on data mapped from a file or when madvise() demands pre-fetching. It is conceptually somewhat similar to VNOP_READ(). Filesystems are typically expected to call cluster_pagein() to handle the labor of mapping and committing the UPL.

Release filesystem-internal resources for a vnode.

struct vnop_pathconf_args { 
    struct vnodeop_desc *a_desc; 
    vnode_t a_vp; 
    int a_name; 
    int32_t *a_retval; 
    vfs_context_t a_context; 
};  

Fields

Discussion

VNOP_RECLAIM() is called as part of the process of recycling a vnode. During a reclaim routine, a filesystem should remove a vnode from its hash and deallocate any resources allocated to that vnode. VFS guarantees that when VNOP_RECLAIM() is called, there are no more iocount references on a vnode (though there may still be usecount references--these are invalidated by the reclaim) and that no more will be granted. This means in practice that there will be no filesystem calls on the vnode being reclaimed until the reclaim has finished and the vnode has been reused.

Call down to a filesystem to set vnode attributes.

struct vnop_read_args { 
    struct vnodeop_desc *a_desc; 
    vnode_t a_vp; 
    struct uio *a_uio; 
    int a_ioflag; 
    vfs_context_t a_context; 
};  

Fields

Discussion

Supported attributes ("Yes, I am setting this attribute.") are set with VATTR_SET_SUPPORTED. Requested attributes are checked with VATTR_IS_ACTIVE. Attribute values are accessed directly through structure fields. VNOP_SETATTR() is the core of the KPI function vnode_setattr(), which is used by chmod(), chown(), truncate(), and many others. A VNOP_SETATTR() call may come without any preceding VNOP_OPEN().

Call down to a filesystem to create a symbolic link.

/*
 *
 *  When VNOP_READDIR is called from the NFS Server, the nfs_data
 *  argument is non-NULL.
 *
 *  The value of nfs_eofflag should be set to TRUE if the end of
 *  the directory was reached while reading.
 *
 *  The directory seek offset (cookies) are returned to the NFS client and
 *  may be used later to restart a directory read part way through
 *  the directory. There is one cookie returned for each directory
 *  entry returned and its size is determince from nfs_sizeofcookie.
 *  The value of the cookie should be the logical offset within the
 *  directory where the on-disc version of the appropriate directory
 *  entry starts. Memory for the cookies is allocated from M_TEMP
 *  and it is freed by the caller of VNOP_READDIR.
 *
    */
struct vnop_readdir_args { 
    struct vnodeop_desc *a_desc; 
    vnode_t a_vp; 
    struct uio *a_uio; 
    int a_flags; 
    int *a_eofflag; 
    int *a_numdirent; 
    vfs_context_t a_context; 
};  

Fields

Call down to a filesystem to enumerate directory entries.

struct vnop_readdirattr_args { 
    struct vnodeop_desc *a_desc; 
    vnode_t a_vp; 
    struct attrlist *a_alist; 
    struct uio *a_uio; 
    uint32_t a_maxcount; 
    uint32_t a_options; 
    uint32_t *a_newstate; 
    int *a_eofflag; 
    uint32_t *a_actualcount; 
    vfs_context_t a_context; 
};  

Fields

Discussion

VNOP_READDIR() packs a buffer with "struct dirent" directory entry representations as described by the "getdirentries" manual page.

Call down to get file attributes for many files in a directory at once.

struct vnop_readlink_args { 
    struct vnodeop_desc *a_desc; 
    vnode_t a_vp; 
    struct uio *a_uio; 
    vfs_context_t a_context; 
};  

Fields

Discussion

VNOP_READDIRATTR() packs a buffer with file attributes, as if the results of many "getattrlist" calls.

Notify a filesystem that the last usecount (persistent reference) on a vnode has been dropped.

struct vnop_reclaim_args { 
    struct vnodeop_desc *a_desc; 
    vnode_t a_vp; 
    vfs_context_t a_context; 
};  

Fields

Discussion

VNOP_INACTVE() gives a filesystem a chance to aggressively release resources assocated with a vnode, perhaps even to call vnode_recycle(), but no action is prescribed; it is acceptable for VNOP_INACTIVE to be a no-op and to defer all reclamation until VNOP_RECLAIM(). VNOP_INACTVE() will not be called on a vnode if no persistent reference is ever taken; an important example is a stat(), which takes an iocount, reads its data, and drops that iocount.

Create a named stream associated with a file.

struct vnop_removenamedstream_args { 
    struct vnodeop_desc *a_desc; 
    vnode_t a_vp; 
    vnode_t a_svp; 
    const char *a_name; 
    int a_flags; 
    vfs_context_t a_context; 
};  

Fields

Discussion

If this call succeeds, svpp should be returned with an iocount which the caller will drop. VFS provides a facility for simulating named streams when interacting with filesystems which do not support them.

Call down to a filesystem to create a hardlink to a file.

struct vnop_rename_args { 
    struct vnodeop_desc *a_desc; 
    vnode_t a_fdvp; 
    vnode_t a_fvp; 
    struct componentname *a_fcnp; 
    vnode_t a_tdvp; 
    vnode_t a_tvp; 
    struct componentname *a_tcnp; 
    vfs_context_t a_context; 
};  

Fields

Discussion

See "man 2 link".

Call down to a filesystem to atomically exchange the data of two files.

struct vnop_revoke_args { 
    struct vnodeop_desc *a_desc; 
    vnode_t a_vp; 
    int a_flags; 
    vfs_context_t a_context; 
};  

Fields

Discussion

VNOP_EXCHANGE() is currently only called by the exchangedata() system call. It will only be applied to files on the same volume.

Call down to a filesystem to create a directory.

struct vnop_rmdir_args { 
    struct vnodeop_desc *a_desc; 
    vnode_t a_dvp; 
    vnode_t a_vp; 
    struct componentname *a_cnp; 
    vfs_context_t a_context; 
};  

Fields

Discussion

The newly created directory should be returned with an iocount which will be dropped by the caller.

Write data from a mapped file back to disk.

struct vnop_searchfs_args { 
    struct vnodeop_desc *a_desc; 
    vnode_t a_vp; 
    void *a_searchparams1; 
    void *a_searchparams2; 
    struct attrlist *a_searchattrs; 
    uint32_t a_maxmatches; 
    struct timeval *a_timelimit; 
    struct attrlist *a_returnattrs; 
    uint32_t *a_nummatches; 
    uint32_t a_scriptcode; 
    uint32_t a_options; 
    struct uio *a_uio; 
    struct searchstate *a_searchstate; 
    vfs_context_t a_context; 
};  

Fields

Discussion

VNOP_PAGEOUT() is called when data from a mapped file needs to be flushed to disk, either because of an msync() call or due to memory pressure. Filesystems are for the most part expected to just call cluster_pageout().

Call down to a filesystem to get vnode attributes.

struct vnop_setattr_args { 
    struct vnodeop_desc *a_desc; 
    vnode_t a_vp; 
    struct vnode_attr *a_vap; 
    vfs_context_t a_context; 
};  

Fields

Discussion

Supported attributes ("Yes, I am returning this information") are set with VATTR_SET_SUPPORTED. Which attributes have been requested is checked with VATTR_IS_ACTIVE. Attributes are returned with VATTR_RETURN. It is through VNOP_GETATTR that routines like stat() get their information. A VNOP_GETATTR() calldown may come without any preceding VNOP_OPEN().

Associate a MACF label with a file.

struct vnop_getnamedstream_args { 
    struct vnodeop_desc *a_desc; 
    vnode_t a_vp; 
    vnode_t *a_svpp; 
    const char *a_name; 
    enum nsoperation a_operation; int a_flags; vfs_context_t a_context; 
};  

Fields

Call down to a filesystem to get information about the on-disk layout of a file region.

struct vnop_strategy_args { 
    struct vnodeop_desc *a_desc; 
    struct buf *a_bp; 
};  

Fields

Discussion

VNOP_BLOCKMAP() returns the information required to pass a request for a contiguous region down to a device's strategy routine.

Call down to a filesystem to delete a directory.

struct vnop_symlink_args { 
    struct vnodeop_desc *a_desc; 
    vnode_t a_dvp; 
    vnode_t *a_vpp; 
    struct componentname *a_cnp; 
    struct vnode_attr *a_vap; 
    char *a_target; 
    vfs_context_t a_context; 
};  

Fields

Call down to a filesystem to create a regular file (VREG).

struct vnop_whiteout_args { 
    struct vnodeop_desc *a_desc; 
    vnode_t a_dvp; 
    struct componentname *a_cnp; 
    int a_flags; 
    vfs_context_t a_context; 
};  

Fields

Discussion

If file creation succeeds, "vpp" should be returned with an iocount to be dropped by the caller. A VNOP_CREATE() calldown can come without a preceding VNOP_OPEN().

Globals

vnop_getxattr_desc

Write data from a mapped file back to disk.

vnop_listxattr_desc

Remove extended file attributes.

Write data from a mapped file back to disk.

extern struct vnodeop_desc vnop_getxattr_desc;  

Fields

Discussion

VNOP_PAGEOUT() is called when data from a mapped file needs to be flushed to disk, either because of an msync() call or due to memory pressure. Filesystems are for the most part expected to just call cluster_pageout().

Remove extended file attributes.

extern struct vnodeop_desc vnop_listxattr_desc;  

Fields

Enumerated Types

nsoperation

Associate a MACF label with a file.

VNOP_SETLABEL

Associate a MACF label with a file.

Associate a MACF label with a file.

 enum nsoperation {
    NS_OPEN,
    NS_CREATE,
    NS_DELETE 
};  

Constants

Associate a MACF label with a file.

 enum nsoperation {
    NS_OPEN,
    NS_CREATE,
    NS_DELETE 
};  

Constants

Last Updated: 2009-10-14