delay in block_read_full_page()

[Michael Mesnier <mmesnier@ece.cmu.edu>]

Hello,

Please cc: me directly in your response.

I'm running into some trouble with an installable file system I'm 
writing. In myfs_readpage() I simply return block_read_full_page() which 
subsequently calls myfs_get_block().  However, there's a delay before 
the I/O actually gets issued to the device.  Running sync from the 
command line causes the I/O to get issued immediately, so the sync call 
(even it there aren't dirty buffers) also manages to schedule any 
outstanding read I/Os. How should my fs indicate to the vfs that these 
read I/Os need to be issued immediately after my_readpage() is called?

Thanks in advanced,

-Mike

static int myfs_get_block(struct inode *inode, long iblock, struct 
buffer_head *bh_result, int create) {
    bh_result->b_dev = inode->i_dev;
    bh_result->b_blocknr = iblock;
    bh_result->b_state |= (1UL << BH_Mapped);
    return 0;
}

static int myfs_readpage(struct file *file, struct page *page) {
    return block_read_full_page(page,myfs_get_block);
}