vfs_fallocate.c 文件参考

浏览源代码.

函数
static ssize_t	file_fallocate (struct file *filep, int mode, off_t offset, off_t len)
int	fallocate (int fd, int mode, off_t offset, off_t len)

函数说明

fallocate()

int fallocate	(	int	fd,
		int	mode,
		off_t	offset,
		off_t	len
	)

在文件 vfs_fallocate.c 第 105 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 (filep->f_oflags & O_DIRECTORY) {
        set_errno(EBADF);
        return VFS_ERROR;
    }
 
    /* Perform the fallocate operation using the file descriptor as an index */
    return file_fallocate(filep, mode, offset, len);
#endif
}

函数调用图:

这是这个函数的调用关系图:

file_fallocate()

static ssize_t file_fallocate ( struct file *  filep, int  mode, off_t  offset, off_t  len  )

static

在文件 vfs_fallocate.c 第 49 行定义.

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

这是这个函数的调用关系图: