mount.h

Includes:

Overview

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

Functions

vfs_64bitready: Check if the filesystem associated with a mountpoint is marked ready for interaction with 64-bit user processes.
vfs_authcache_ttl: Determine the time-to-live of cached authorized credentials for files in this filesystem.
vfs_authopaque: Determine if a filesystem's authorization decisions occur remotely.
vfs_authopaqueaccess: Check if a filesystem is marked as having reliable remote VNOP_ACCESS support.
vfs_busy: "Busy" a mountpoint.
vfs_clearauthcache_ttl: Remove time-to-live controls for cached credentials on a filesytem. Filesystems with remote authorization decisions (opaque) will still have KAUTH_VNODE_SEARCH rights cached for a default of CACHED_LOOKUP_RIGHT_TTL seconds.
vfs_clearauthopaque(mount_t): Mark a filesystem as not having remote authorization decisions.
vfs_clearauthopaque(mount_t): Mark a filesystem as not having remote VNOP_ACCESS support.
vfs_clearauthopaqueaccess: Mark a filesystem as not having remote VNOP_ACCESS support.
vfs_clearextendedsecurity: Mark a filesystem as NOT supporting security controls beyond POSIX permissions.
vfs_clearflags: Clear flags on a mount.
vfs_devblocksize: Get the block size of the device underlying a mount.
vfs_event_init: This function should not be called by kexts.
vfs_event_signal: Post a kqueue-style event on a filesystem (EVFILT_FS).
vfs_fhtovp: Get the vnode corresponding to a file handle.
vfs_flags: Retrieve mount flags.
vfs_fsadd: Register a filesystem with VFS.
vfs_fsprivate: Get filesystem-private mount data.
vfs_fsremove: Unregister a filesystem with VFS.
vfs_getattr: Get filesystem attributes.
vfs_getnewfsid: Generate a unique filesystem ID for a mount and store it in the mount structure.
vfs_getvfs: Given a filesystem ID, look up a mount structure.
vfs_init: Prepare a filesystem for having instances mounted.
vfs_init_io_attributes: Set I/O attributes on a mountpoint based on device properties.
vfs_ioattr: Get I/O attributes associated with a mounpoint.
vfs_isforce: Determine if a forced unmount is in progress.
vfs_isrdonly: Determine if a filesystem is mounted read-only.
vfs_isrdwr: Determine if a filesystem is mounted with writes enabled.
vfs_isreload: Determine if a reload of filesystem data is in progress. This can only be the case for a read-only filesystem; all data is brought in from secondary storage.
vfs_issynchronous: Determine if writes to a filesystem occur synchronously.
vfs_isunmount: Determine if an unmount is in progress.
vfs_isupdate: Determine if a mount update is in progress.
vfs_iswriteupgrade: Determine if a filesystem is mounted read-only but a request has been made to upgrade to read-write.
vfs_iterate: Iterate over all mountpoints with a callback. Used, for example, by sync().
vfs_maxsymlen: Get the maximum length of a symbolic link on a filesystem.
vfs_mount: Perform filesystem-specific operations required for mounting.
vfs_mountedon: Check whether a given block device has a filesystem mounted on it.
vfs_name: Copy filesystem name into a buffer.
vfs_quotactl: Manipulate quotas for a volume.
vfs_root: Get the root vnode of a filesystem.
vfs_setattr: Set filesystem attributes.
vfs_setauthcache_ttl: Enable credential caching and set time-to-live of cached authorized credentials for files in this filesystem.
vfs_setauthopaque: Mark a filesystem as having authorization decisions controlled remotely.
vfs_setauthopaqueaccess: Mark a filesystem as having remote VNOP_ACCESS support.
vfs_setextendedsecurity: Mark a filesystem as supporting security controls beyond POSIX permissions.
vfs_setflags: Set flags on a mount.
vfs_setfsprivate: Set filesystem-private mount data.
vfs_setioattr: Set I/O attributes associated with a mounpoint.
vfs_setlocklocal: Mark a filesystem as using VFS-level advisory locking support.
vfs_setmaxsymlen: Set the maximum length of a symbolic link on a filesystem.
vfs_start: Mark a mount as ready to be used.
vfs_statfs: Get information about filesystem status.
vfs_sync: Flush all filesystem data to backing store.
vfs_sysctl: Broad interface for querying and controlling filesystem.
vfs_typenum: Get (archaic) filesystem type number.
vfs_unbusy: "Unbusy" a mountpoint by releasing its read-write lock.
vfs_unmount: Perform filesystem-specific cleanup as part of unmount.
vfs_unmountbyfsid: Find a filesystem by ID and unmount it.
vfs_update_vfsstat: Update cached filesystem status information in the VFS mount structure.
vfs_vget: Get a vnode by file id (inode number).
vfs_vptofh: Get a persistent handle corresponding to a vnode.

vfs_64bitready

Check if the filesystem associated with a mountpoint is marked ready for interaction with 64-bit user processes.


int vfs_64bitready(
    mount_t);

Parameters

mp: Mount to test.

Return Value

Nonzero if filesystem is ready for 64-bit; 0 otherwise.

vfs_authcache_ttl

Determine the time-to-live of cached authorized credentials for files in this filesystem.


int vfs_authcache_ttl(
    mount_t);

Parameters

mp: Mount for which to check cache lifetime.

Return Value

Cache lifetime in seconds. CACHED_RIGHT_INFINITE_TTL indicates that credentials never expire.

Discussion

If a filesystem is set to allow caching credentials, the VFS layer can authorize previously-authorized actions from the same vfs_context_t without calling down to the filesystem (though it will not deny based on the cache).

vfs_authopaque

Determine if a filesystem's authorization decisions occur remotely.


int vfs_authopaque(
    mount_t);

Parameters

mp: Mount to test.

Return Value

Nonzero if filesystem authorization is controlled remotely, else 0.

vfs_authopaqueaccess

Check if a filesystem is marked as having reliable remote VNOP_ACCESS support.


int vfs_authopaqueaccess(
    mount_t);

Parameters

mp: Mount to test.

Return Value

Nonzero if VNOP_ACCESS is supported remotely, else 0.

vfs_busy

"Busy" a mountpoint.


int vfs_busy(
    mount_t,
    int);

Parameters

mp: Mount to busy.
flags: LK_NOWAIT: fail with ENOENT if an unmount is in progress.

Return Value

0 for success, with a lock held; an error code otherwise, with no lock held.

Discussion

vfs_busy() will "busy" a mountpoint, preventing unmounts from taking off, by taking its reader-writer lock in a shared manner. If a mount is dead, it will fail; if an unmount is in progress, depending on flags, it will either fail immediately or block until the unmount completes (then failing if the unmount has succeeded, or potentially succeeding if unmounting failed). A successful vfs_busy() must be followed by a vfs_unbusy() to release the lock on the mount.

vfs_clearauthcache_ttl

Remove time-to-live controls for cached credentials on a filesytem. Filesystems with remote authorization decisions (opaque) will still have KAUTH_VNODE_SEARCH rights cached for a default of CACHED_LOOKUP_RIGHT_TTL seconds.


void vfs_clearauthcache_ttl(
    mount_t);

Parameters

mp: Mount for which to clear cache lifetime.

Return Value

void.

vfs_clearauthopaque(mount_t)

Mark a filesystem as not having remote authorization decisions.


void vfs_clearauthopaque(
    mount_t);

Parameters

mp: Mount to mark.

Return Value

void.

vfs_clearauthopaque(mount_t)

Mark a filesystem as not having remote VNOP_ACCESS support.


void vfs_clearauthopaqueaccess(
    mount_t);

Parameters

mp: Mount to mark.

Return Value

void.

vfs_clearauthopaqueaccess

Mark a filesystem as not having remote VNOP_ACCESS support.


void vfs_clearauthopaqueaccess(
    mount_t);

Parameters

mp: Mount to mark.

Return Value

void.

vfs_clearextendedsecurity

Mark a filesystem as NOT supporting security controls beyond POSIX permissions.


void vfs_clearextendedsecurity(
    mount_t);

Parameters

mp: Mount to test.

Return Value

void.

Discussion

Specific controls include ACLs, file owner UUIDs, and group UUIDs.

vfs_clearflags

Clear flags on a mount.


void vfs_clearflags(
    mount_t,
    uint64_t);

Parameters

mp: Mount whose flags to set.
flags: Flags to deactivate. Must be in the bitwise "OR" of MNT_VISFLAGMASK and MNT_CMDFLAGS.

Return Value

void.

Discussion

Sets mount flags to the bitwise "AND" of their current value and the complement of the specified bits.

vfs_devblocksize

Get the block size of the device underlying a mount.


int vfs_devblocksize(
    mount_t);

Parameters

mp: Mount for which to get block size.

Return Value

Block size.

vfs_event_init

This function should not be called by kexts.


void vfs_event_init(
    void);  /* XXX We should not export this */

vfs_event_signal

Post a kqueue-style event on a filesystem (EVFILT_FS).


void vfs_event_signal(
    fsid_t *,
    u_int32_t,
    intptr_t);

Parameters

fsid: Unused.
event: Events to post.
data: Unused.

Return Value

void.

vfs_fhtovp

Get the vnode corresponding to a file handle.


int ( *vfs_fhtovp)(
    struct mount *mp,
    int fhlen,
    unsigned char *fhp,
    struct vnode **vpp, 
    vfs_context_t context);

Parameters

mp: Mount against which to look up file handle.
fhlen: Size of file handle structure, as returned by vfs_vptofh.
fhp: Pointer to handle.
vpp: Destination for vnode.
ctx: Context against which to authenticate the file-handle conversion.

Return Value

0 for success, else an error code.

Discussion

Filesystems can return handles to files which are independent of their (transient) vnode identities. vfs_thtovp converts that persistent handle back to a vnode. The vnode should be returned with an iocount which the caller will drop with vnode_put().

vfs_flags

Retrieve mount flags.


uint64_t vfs_flags(
    mount_t);

Parameters

mp: Mount whose flags to grab.

Return Value

Flags.

Discussion

Results will be in the bitwise "OR" of MNT_VISFLAGMASK and MNT_CMDFLAGS.

vfs_fsadd


int vfs_fsadd(
    struct vfs_fsentry *,
    vfstable_t *);

Parameters

vfe: Filesystem information: table of vfs operations, list of vnode operation tables, filesystem type number (can be omitted with VFS_TBLNOTYPENUM flag), name, flags.
handle: Opaque handle which will be passed to vfs_fsremove.

Return Value

0 for success, else an error code.

Discussion

Typically called by a filesystem Kernel Extension when it is loaded.

vfs_fsprivate

Get filesystem-private mount data.


void * vfs_fsprivate(
    mount_t);

Parameters

mp: Mount for which to get private data.

Return Value

Private data.

Discussion

A filesystem generally has an internal mount structure which it attaches to the VFS-level mount structure as part of the mounting process.

vfs_fsremove

Unregister a filesystem with VFS.


int vfs_fsremove(
    vfstable_t);

Parameters

handle: Handle which was returned by vfs_fsadd.

Return Value

0 for success, else an error code.

Discussion

Typically called by a filesystem Kernel Extension when it is unloaded.

vfs_getattr

Get filesystem attributes.


int ( *vfs_getattr)(
    struct mount *mp,
    struct vfs_attr *,
    vfs_context_t context);

Parameters

mp: Mount for which to get parameters.
vfa: Container for specifying which attributes are desired and which attributes the filesystem supports, as well as for returning results.
ctx: Context to authenticate for getting filesystem attributes.

Return Value

0 for success, else an error code.

Discussion

See VFSATTR_RETURN, VFSATTR_ACTIVE, VFSATTR_SET_SUPPORTED, VFSATTR_WANTED macros.

vfs_getnewfsid

Generate a unique filesystem ID for a mount and store it in the mount structure.


void vfs_getnewfsid(
    struct mount *);

Parameters

mp: Mount to set an ID for.

Return Value

void.

Discussion

Filesystem IDs are returned as part of "struct statfs." This function is typically called as part of file-system specific mount code (i.e. through VFS_MOUNT).

vfs_getvfs

Given a filesystem ID, look up a mount structure.


mount_t vfs_getvfs(
    fsid_t *);

Parameters

fsid: Filesystem ID to look up.

Return Value

Mountpoint if found, else NULL. Note unmounting mountpoints can be returned.

vfs_init

Prepare a filesystem for having instances mounted.


int ( *vfs_init)(
    struct vfsconf *);

Parameters

vfsconf: Configuration information. Currently, the only useful data are the filesystem name, typenum, and flags. The flags field will be either 0 or MNT_LOCAL. Many filesystems ignore this parameter.

Return Value

0 for success, else an error code.

Discussion

This routine is called once, before any particular instance of a filesystem is mounted; it allows the filesystem to initialize whatever global data structures are shared across all mounts. If this returns successfully, a filesystem should be ready to have instances mounted.

vfs_init_io_attributes

Set I/O attributes on a mountpoint based on device properties.


int vfs_init_io_attributes(
    vnode_t,
    mount_t);

Parameters

devvp: Block device vnode from which a filesystem is being mounted.
mp: Mountpoint whose I/O parameters to initialize.

Return Value

0 for success, else an error code.

vfs_ioattr

Get I/O attributes associated with a mounpoint.


void vfs_ioattr(
    mount_t,
    struct vfsioattr *);

Parameters

mp: Mount for which to get attributes. If NULL, system defaults are filled into ioattrp.
ioattrp: Destination for results.

Return Value

void.

vfs_isforce

Determine if a forced unmount is in progress.


int vfs_isforce(
    mount_t);

Parameters

mp: Mount to test.

Return Value

Nonzero if a request has been made to forcibly unmount, else 0.

Discussion

A forced unmount invalidates open files.

vfs_isrdonly

Determine if a filesystem is mounted read-only.


int vfs_isrdonly(
    mount_t);

Parameters

mp: Mount to test.

Return Value

Nonzero if filesystem is mounted read-only, else 0.

vfs_isrdwr

Determine if a filesystem is mounted with writes enabled.


int vfs_isrdwr(
    mount_t);

Parameters

mp: Mount to test.

Return Value

Nonzero if filesystem is mounted read-write, else 0.

vfs_isreload

Determine if a reload of filesystem data is in progress. This can only be the case for a read-only filesystem; all data is brought in from secondary storage.


int vfs_isreload(
    mount_t);

Parameters

mp: Mount to test.

Return Value

Nonzero if a request has been made to reload data, else 0.

vfs_issynchronous

Determine if writes to a filesystem occur synchronously.


int vfs_issynchronous(
    mount_t);

Parameters

mp: Mount to test.

Return Value

Nonzero if writes occur synchronously, else 0.

vfs_isunmount

Determine if an unmount is in progress.


int vfs_isunmount(
    mount_t mp);

Parameters

mp: Mount to test.

Return Value

Nonzero if an unmount is in progress, else zero.

Discussion

This is an unsynchronized snapshot of the mount state. It should only be called if the mount is known to be valid, e.g. there are known to be live files on that volume.

vfs_isupdate

Determine if a mount update is in progress.


int vfs_isupdate(
    mount_t);

Parameters

mp: Mount to test.

Return Value

Nonzero if a mount update is in progress, 0 otherwise.

vfs_iswriteupgrade

Determine if a filesystem is mounted read-only but a request has been made to upgrade to read-write.


int vfs_iswriteupgrade(
    mount_t);

Parameters

mp: Mount to test.

Return Value

Nonzero if a request has been made to update from read-only to read-write, else 0.

vfs_iterate

Iterate over all mountpoints with a callback. Used, for example, by sync().


int vfs_iterate(
    int,
    int (*)(
        struct mount *,
        void *),
    void *);

Parameters

flags: Unused.
callback: Function which takes a mount and arbitrary passed-in "arg," and returns one of VFS_RETURNED_DONE or VFS_CLAIMED_DONE: end iteration and return success. VFS_RETURNED or VFS_CLAIMED: continue iterating. Anything else: continue iterating.
arg: Arbitrary data to pass to callback.

Return Value

0 for success, else an error code.

vfs_maxsymlen

Get the maximum length of a symbolic link on a filesystem.


uint32_t vfs_maxsymlen(
    mount_t);

Parameters

mp: Mount from which to get symlink length cap.

Return Value

Max symlink length.

vfs_mount

Perform filesystem-specific operations required for mounting.


int ( *vfs_mount)(
    struct mount *mp,
    vnode_t devvp,
    user_addr_t data,
    vfs_context_t context);

Parameters

mp: Mount structure for the newly mounted filesystem.
devvp: Device that the filesystem is mounted from.
data: Filesystem-specific data passed down from userspace.
context: Context to authenticate for mount.

Return Value

0 for success, else an error code. Once success is returned, the filesystem should be ready to go active; VFS will not ask again.

Discussion

Typical operations include setting the mount-specific data with vfs_setfsprivate(). Note that if a mount call fails, the filesystem must clean up any state it has constructed, because vfs-level mount code will not clean it up.

vfs_mountedon

Check whether a given block device has a filesystem mounted on it.


int vfs_mountedon(
    struct vnode *);

Parameters

vp: The vnode to test.

Return Value

EBUSY if vnode is indeed the source of a filesystem; 0 if it is not.

Discussion

Note that this is NOT a check for a covered vnode (the directory upon which a filesystem is mounted)--it is a test for whether a block device is being used as the source of a filesystem. Note that a block device marked as being mounted on cannot be opened.

vfs_name

Copy filesystem name into a buffer.


void vfs_name(
    mount_t,
    char *);

Parameters

mp: Mount for which to get name.
buffer: Destination for name; length should be at least MFSNAMELEN.

Return Value

void.

Discussion

Get filesystem name; this refers to the filesystem type of which a mount is an instantiation, rather than a name specific to the mountpoint.

vfs_quotactl

Manipulate quotas for a volume.


int ( *vfs_quotactl)(
    struct mount *mp,
    int cmds,
    uid_t uid,
    caddr_t arg,
    vfs_context_t context);

Parameters

mp: Mount for which to manipulate quotas.
cmds: Detailed in "quotactl" manual page.
uid: Detailed in "quotactl" manual page.
arg: Detailed in "quotactl" manual page.
context: Context to authenticate for changing quotas.

Return Value

0 for success, else an error code.

vfs_root

Get the root vnode of a filesystem.


int ( *vfs_root)(
    struct mount *mp,
    struct vnode **vpp,
    vfs_context_t context);

Parameters

mp: Mount for which to get the root.
vpp: Destination for root vnode.
context: Context to authenticate for getting the root.

Return Value

0 for success, else an error code.

Discussion

Upon success, should return with an iocount held on the root vnode which the caller will drop with vnode_put().

vfs_setattr

Set filesystem attributes.


int ( *vfs_setattr)(
    struct mount *mp,
    struct vfs_attr *,
    vfs_context_t context);

Parameters

mp: Mount on which to set attributes.
vfa: VFS attribute structure containing requested attributes to set and their values. Currently will only be called with f_vol_name set.
context: Context against which to authenticate attribute change.

Return Value

0 for success, else an error code.

Discussion

The other side of the vfs_getattr coin. Currently only called to set volume name.

vfs_setauthcache_ttl

Enable credential caching and set time-to-live of cached authorized credentials for files in this filesystem.


void vfs_setauthcache_ttl(
    mount_t,
    int);

Parameters

mp: Mount for which to set cache lifetime.

Return Value

void.

Discussion

vfs_setauthopaque

Mark a filesystem as having authorization decisions controlled remotely.


void vfs_setauthopaque(
    mount_t);

Parameters

mp: Mount to mark.

Return Value

void.

vfs_setauthopaqueaccess

Mark a filesystem as having remote VNOP_ACCESS support.


void vfs_setauthopaqueaccess(
    mount_t);

Parameters

mp: Mount to mark.

Return Value

void.

vfs_setextendedsecurity

Mark a filesystem as supporting security controls beyond POSIX permissions.


void vfs_setextendedsecurity(
    mount_t);

Parameters

mp: Mount to test.

Return Value

void.

Discussion

Specific controls include ACLs, file owner UUIDs, and group UUIDs.

vfs_setflags

Set flags on a mount.


void vfs_setflags(
    mount_t,
    uint64_t);

Parameters

mp: Mount whose flags to set.
flags: Flags to activate. Must be in the bitwise "OR" of MNT_VISFLAGMASK and MNT_CMDFLAGS.

Return Value

Flags.

Discussion

Sets mount flags to the bitwise "OR" of their current value and the specified bits. Often used by a filesystem as part of the mount process.

vfs_setfsprivate

Set filesystem-private mount data.


void vfs_setfsprivate(
    mount_t,
    void *mntdata);

Parameters

mp: Mount for which to set private data.

Return Value

Void.

Discussion

A filesystem generally has an internal mount structure which it attaches to the VFS-level mount structure as part of the mounting process.

vfs_setioattr

Set I/O attributes associated with a mounpoint.


void vfs_setioattr(
    mount_t,
    struct vfsioattr *);

Parameters

mp: Mount for which to set attributes.
ioattrp: Structure containing I/O parameters; all fields must be filled in.

Return Value

void.

vfs_setlocklocal

Mark a filesystem as using VFS-level advisory locking support.


void vfs_setlocklocal(
    mount_t);

Parameters

mp: Mount to mark.

Return Value

void.

Discussion

Advisory locking operations will not call down to the filesystem if this flag is set.

vfs_setmaxsymlen

Set the maximum length of a symbolic link on a filesystem.


void vfs_setmaxsymlen(
    mount_t,
    uint32_t);

Parameters

mp: Mount on which to set symlink length cap.
symlen: Length to set.

Return Value

Max symlink length.

vfs_start

Mark a mount as ready to be used.


int ( *vfs_start)(
    struct mount *mp,
    int flags,
    vfs_context_t context);

Parameters

mp: Mount structure being activated.
flags: Unused.
context: Context to authenticate for mount.

Return Value

Return value is ignored.

Discussion

After receiving this calldown, a filesystem will be hooked into the mount list and should expect calls down from the VFS layer.

vfs_statfs

Get information about filesystem status.


struct vfsstatfs * vfs_statfs(
    mount_t);

Parameters

mp: Mount for which to get vfsstatfs pointer.

Return Value

Pointer to vfsstatfs.

Discussion

Each filesystem has a struct vfsstatfs associated with it which is updated as events occur; this function returns a pointer to it. Note that the data in the structure will continue to change over time and also that it may be quite stale of vfs_update_vfsstat has not been called recently.

vfs_sync

Flush all filesystem data to backing store.


int ( *vfs_sync)(
    struct mount *mp,
    int waitfor,
    vfs_context_t context);

Parameters

mp: Mountpoint to sync.
waitfor: MNT_WAIT: flush synchronously, waiting for all data to be written before returning. MNT_NOWAIT: start I/O but do not wait for it.
ctx: Context to authenticate for the sync.

Return Value

0 for success, else an error code.

Discussion

vfs_sync will be called as part of the sync() system call and during unmount.

vfs_sysctl

Broad interface for querying and controlling filesystem.


int ( *vfs_sysctl)(
    int *,
    u_int,
    user_addr_t,
    size_t *,
    user_addr_t,
    size_t,
    vfs_context_t context);

Parameters

context: Context against which to authenticate command.

Return Value

0 for success, else an error code.

Discussion

VFS defines VFS_CTL_QUERY as a generic status request which is answered with the VQ_* macros in a "struct vfsquery." A filesystem may also define implementation-specific commands. See "man 3 sysctl" for the meaning of sysctl parameters.

vfs_typenum

Get (archaic) filesystem type number.


int vfs_typenum(
    mount_t);

Parameters

mp: Mount for which to get type number.

Return Value

Type number.

Discussion

Filesystem type numbers are an old construct; most filesystems just get a number assigned based on the order in which they are registered with the system.

vfs_unbusy

"Unbusy" a mountpoint by releasing its read-write lock.


void vfs_unbusy(
    mount_t);

Parameters

mp: Mount to unbusy.

Return Value

void.

Discussion

A successful vfs_busy() must be followed by a vfs_unbusy() to release the lock on the mount.

vfs_unmount

Perform filesystem-specific cleanup as part of unmount.


int ( *vfs_unmount)(
    struct mount *mp,
    int mntflags,
    vfs_context_t context);

Parameters

mp: Mount structure to unmount.
mntflags: MNT_FORCE indicates that we wish to unmount even if there are active vnodes.
context: Context to authenticate for unmount.

Return Value

0 for success, else an error code.

Discussion

If the unmount downcall succeeds, VFS considers itself authorized to destroy all state related to the mount.

vfs_unmountbyfsid

Find a filesystem by ID and unmount it.


int vfs_unmountbyfsid(
    fsid_t *,
    int,
    vfs_context_t);

Parameters

fsid: ID of filesystem to unmount, as found through (for example) statfs.
flags: MNT_FORCE: forcibly invalidate files open on the mount (though in-flight I/O operations will be allowed to complete).
ctx: Context against which to authenticate unmount operation.

Return Value

0 for succcess, nonero for failure.

vfs_update_vfsstat

Update cached filesystem status information in the VFS mount structure.


int vfs_update_vfsstat(
    mount_t,
    vfs_context_t,
    int eventtype);

Parameters

mp: Mount for which to update cached status information.
ctx: Context to authenticate against for call down to filesystem.
eventtype: VFS_USER_EVENT: need for update is driven by user-level request; perform additional authentication. VFS_KERNEL_EVENT: need for update is driven by in-kernel events. Skip extra authentication.

Return Value

0 for success, or an error code for authentication failure or problem with call to filesystem to request information.

Discussion

Each filesystem has a struct vfsstatfs associated with it which is updated as events occur; this function updates it so that the structure pointer returned by vfs_statfs() returns a pointer to fairly recent data.

vfs_vget

Get a vnode by file id (inode number).


int ( *vfs_vget)(
    struct mount *mp,
    ino64_t ino,
    struct vnode **vpp,
    vfs_context_t context);

Parameters

mp: Mount against which to look up inode number.
ino: File ID for desired file, as found through a readdir.
vpp: Destination for vnode.

Return Value

0 for success, else an error code.

Discussion

This routine is chiefly used to build paths to vnodes. Result should be turned with an iocount that the caller will drop with vnode_put().

vfs_vptofh

Get a persistent handle corresponding to a vnode.


int ( *vfs_vptofh)(
    struct vnode *vp,
    int *fhlen,
    unsigned char *fhp,
    vfs_context_t context);

Parameters

mp: Mount against which to convert the vnode to a handle.
fhlen: Size of buffer provided for handle; set to size of actual handle returned.
fhp: Pointer to buffer in which to place handle data.
ctx: Context against which to authenticate the file-handle request.

Return Value

0 for success, else an error code.

Mac Dev Center Mac OS X Reference Library Drivers, Kernel, & Hardware: Kernel Device Drivers Kernel Framework Reference

Did this document help you?

Shop the Apple Online Store (1-800-MY-APPLE), visit an Apple Retail Store, or find a reseller.

Last Updated: 2010-07-29