vfs_getnewfsid (9)

Leading comments

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
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2. Redistributions in binary for...

(The comments found at the beginning of the groff file "man9/vfs_getnewfsid.9freebsd".)

NAME

vfs_getnewfsid - allocate a new file system identifier

SYNOPSIS

In sys/param.h In sys/mount.h Ft void Fn vfs_getnewfsid struct mount *mp

DESCRIPTION

The Fn vfs_getnewfsid function allocates a new file system identifier for the mount point given. File systems typically call Fn vfs_getnewfsid in their mount routine in order to acquire a unique ID within the system which can later be used to uniquely identify the file system via calls such as vfs_getvfs9.

The actual Vt fsid is made up of two 32 bit integers, that are stored in the Vt statfs structure of Fa mp . The first integer is unique in the set of mounted file systems, while the second holds the file system type.

typedef struct fsid {
        int32_t val[2];
} fsid_t;

PSEUDOCODE

xxx_mount(struct mount *mp, char *path, caddr_t data,
        struct nameidata *ndp, struct thread *td)
{
        ...
        vfs_getnewfsid(mp);
        ...
}

SEE ALSO

vfs_getvfs9

AUTHORS

This manual page was written by An Chad David Aq davidc@acns.ab.ca .