vfs_fallocate64.c 文件参考

浏览源代码.

函数
ssize_t	file_fallocate64 (struct file *filep, int mode, off64_t offset, off64_t len)
int	fallocate64 (int fd, int mode, off64_t offset, off64_t len)

函数说明

fallocate64()

int fallocate64	(	int	fd,
		int	mode,
		off64_t	offset,
		off64_t	len
	)

在文件 vfs_fallocate64.c 第 108 行定义.

{
#if CONFIG_NFILE_DESCRIPTORS > 0
    struct file *filep = NULL;
#endif
 
    /* Did we get a valid file descriptor? */
 
#if CONFIG_NFILE_DESCRIPTORS > 0
    if ((unsigned int)fd >= CONFIG_NFILE_DESCRIPTORS)
#endif
    {
        set_errno(EBADF);
        return VFS_ERROR;
    }
 
#if CONFIG_NFILE_DESCRIPTORS > 0
 
    /* The descriptor is in the right range to be a file descriptor... write
     * to the file.
     */
 
    int ret = fs_getfilep(fd, &filep);
    if (ret < 0) {
        /* The errno value has already been set */
        return VFS_ERROR;
    }
 
    if ((unsigned int)filep->f_oflags & O_DIRECTORY) {
        set_errno(EBADF);
        return VFS_ERROR;
    }
 
    /* Perform the fallocate operation using the file descriptor as an index */
    return file_fallocate64(filep, mode, offset, len);
#endif
}

函数调用图:

这是这个函数的调用关系图:

file_fallocate64()

ssize_t file_fallocate64	(	struct file *	filep,
		int	mode,
		off64_t	offset,
		off64_t	len
	)

在文件 vfs_fallocate64.c 第 49 行定义.

{
    int ret;
    int err;
 
    if (len <= 0) {
        err = EINVAL;
        goto errout;
    }
 
    /* Was this file opened for write access? */
 
    if (((unsigned int)(filep->f_oflags) & O_ACCMODE) == O_RDONLY) {
        err = EACCES;
        goto errout;
    }
 
    /* Is a driver registered? Does it support the fallocate method? */
    if (!filep->ops || !filep->ops->fallocate64) {
        err = EBADF;
        goto errout;
    }
 
    /* Yes, then let the driver perform the fallocate */
 
    ret = filep->ops->fallocate64(filep, mode, offset, len);
    if (ret < 0) {
        err = -ret;
        goto errout;
    }
 
    return ret;
 
errout:
    set_errno(err);
    return VFS_ERROR;
}

这是这个函数的调用关系图: