xref: /freebsd/share/man/man9/VOP_ALLOCATE.9 (revision 7ef62cebc2f965b0f640263e179276928885e33d)
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30.Dd November 8, 2021
31.Dt VOP_ALLOCATE 9
32.Os
33.Sh NAME
34.Nm VOP_ALLOCATE
35.Nd allocate storage for a file
36.Sh SYNOPSIS
37.In sys/param.h
38.In sys/vnode.h
39.Ft int
40.Fo VOP_ALLOCATE
41.Fa "struct vnode *vp"
42.Fa "off_t *offset"
43.Fa "off_t *len"
44.Fa "int ioflag"
45.Fa "struct ucred *cred"
46.Fc
47.Sh DESCRIPTION
48This call allocates storage for a range of offsets in a file.
49It is used to implement the
50.Xr posix_fallocate
51system call.
52.Pp
53Its arguments are:
54.Bl -tag -width offset
55.It Fa vp
56The vnode of the file.
57.It Fa offset
58The start of the range to allocate storage for in the file.
59.It Fa len
60The length of the range to allocate storage for in the file.
61.It Fa ioflag
62Directives and hints to be given to the file system.
63.It Fa cred
64The credentials of the caller.
65.El
66.Pp
67The
68.Fa offset
69and
70.Fa len
71arguments are updated to reflect the portion of the range that
72still needs to be allocated on return.
73A partial allocation is considered a successful operation.
74The file's contents are not changed.
75.Sh LOCKS
76The file should be exclusively locked on entry and will still be locked on exit.
77.Sh RETURN VALUES
78Zero is returned if the call is successful, otherwise an appropriate
79error code is returned.
80.Sh ERRORS
81.Bl -tag -width Er
82.It Bq Er EFBIG
83An attempt was made to write a file that exceeds the process's file size
84limit or the maximum file size.
85.It Bq Er ENOSPC
86The file system is full.
87.It Bq Er EPERM
88An append-only flag is set on the file, but the caller is attempting to
89write before the current end of file.
90.El
91.Sh SEE ALSO
92.Xr vnode 9 ,
93.Xr VOP_READ 9 ,
94.Xr VOP_WRITE 9
95