Manual Pages  — FSPACECTL

fspacectl – space management in a file

LIBRARY SYNOPSIS DESCRIPTION RETURN VALUES ERRORS SEE ALSO HISTORY AUTHORS

Standard C Library (libc, -lc)

#include <fcntl.h>

int
fspacectl(int fd, int cmd, const struct spacectl_range *rqsr, int flags, struct spacectl_range *rmsr);

fspacectl is a system call performing space management over a file. The fd argument specifies the file descriptor to be operated on by the cmd argument. The rqsr argument points to a spacectl_range structure that contains the requested operation range. The flags argument controls the behavior of the operation to take place. If the rmsr argument is non-NULL, the spacectl_range structure it points to is updated to contain the unprocessed operation range after the system call returns.

For a successful completion without an unprocessed part in the requested operation range, rmsr->r_len is updated to be the value 0, and rmsr->r_offset is updated to be rqsr->r_offset plus the number of bytes zeroed before the end-of-file. The file descriptor's file offset is not used or modified by the system call. Both rqsr and rmsr arguments can point to the same structure.

The spacectl_range structure is defined as:

struct spacectl_range {
        off_t r_offset;
        off_t r_len;
};

The operation specified by the cmd argument may be one of:

SPACECTL_DEALLOC
	Zero a region in the file specified by the rqsr argument. The rqsr->r_offset has to be a value greater than or equal to 0, and the rqsr->r_len has to be a value greater than 0. If the file system supports hole-punching, file system space deallocation may be performed in the given region.

The flags argument needs to be the value 0 currently.

Upon successful completion, the value 0 is returned; otherwise the value -1 is returned and errno is set to indicate the error.

Possible failure conditions:

[EBADF]
	The fd argument is not a valid file descriptor.
[EBADF]
	The fd argument references a file that was opened without write permission.
[EINTR]
	A signal was caught during execution.
[EINVAL]
	The cmd argument is not valid.
[EINVAL]
	If the cmd argument is SPACECTL_DEALLOC, either the rqsr->r_offset argument was less than zero, or the rqsr->r_len argument was less than or equal to zero.
[EINVAL]
	The value of rqsr->r_offset, + rqsr->r_len is greater than OFF_MAX.
[EINVAL]
	An invalid or unsupported flag is included in flags.
[EINVAL]
	A flag included in flags is not supported by the operation specified by the cmd argument.
[EFAULT]
	The rqsr or a non-NULL rmsr argument point outside the process' allocated address space.
[EIO]	An I/O error occurred while reading from or writing to a file system.
[EINTEGRITY]
	Corrupted data was detected while reading from the file system.
[ENODEV]
	The fd argument does not refer to a file that supports fspacectl.
[ENOSPC]
	There is insufficient free space remaining on the file system storage media.
[ENOTCAPABLE]
	The file descriptor fd has insufficient rights.
[ESPIPE]
	The fd argument is associated with a pipe or FIFO.

The fspacectl system call appeared in FreeBSD 14.0 .

fspacectl and this manual page were written by Ka Ho Ng <Mt khng@FreeBSD.org> under sponsorship from the FreeBSD Foundation.