kernel - 当我说 "cat myfile >/dev/sda"时，调用了什么内核模块函数

Question

我浏览了Linux Kernel Module Programming指导，但无法弄清楚:

当我说 cat image.iso > /dev/sda ，会不会导致write file_operations structure的功能由 sda 执行设备驱动？还是文件接口(interface)不适用于 block 设备节点？

我在哪里可以找到该函数的实现？ (Linux code tree 中的相应驱动程序)？

Answer 1

fs/block-dev.c 定义了适用于 block 设备的文件操作和地址空间操作。

static const struct address_space_operations def_blk_aops = {
    .readpage       = blkdev_readpage,
    .writepage      = blkdev_writepage,
    .write_begin    = blkdev_write_begin,
    .write_end      = blkdev_write_end,
    .writepages     = generic_writepages,
    .releasepage    = blkdev_releasepage,
    .direct_IO      = blkdev_direct_IO,
    .is_dirty_writeback = buffer_check_dirty_writeback,
};

const struct file_operations def_blk_fops = {
    .open           = blkdev_open,
    .release        = blkdev_close,
    .llseek         = block_llseek,
    .read           = do_sync_read,
    .write          = do_sync_write,
    .aio_read       = blkdev_aio_read,
    .aio_write      = blkdev_aio_write,
    .mmap           = generic_file_mmap,
    .fsync          = blkdev_fsync,
    .unlocked_ioctl = block_ioctl,
#ifdef CONFIG_COMPAT
    .compat_ioctl   = compat_blkdev_ioctl,
#endif
    .splice_read    = generic_file_splice_read,
    .splice_write   = generic_file_splice_write,
};