Re: [dm-devel] [PATCH] dm-bufio

[Joe Thornber <thornber redhat com>]

On Fri, Oct 14, 2011 at 03:14:34PM -0400, Mikulas Patocka wrote:
@@ -493,8 +500,10 @@ static void use_inline_bio(struct dm_buf
 static void submit_io(struct dm_buffer *b, int rw, sector_t block,
                      bio_end_io_t *end_io)
 {
-       if (b->c->block_size <= DM_BUFIO_INLINE_VECS * PAGE_SIZE &&
-           b->data_mode != DATA_MODE_VMALLOC)
+       if (rw == WRITE && b->c->write_callback)
+               b->c->write_callback(b);
        if (likely(b->c->block_size <= DM_BUFIO_INLINE_VECS * PAGE_SIZE) &&
            likely(b->data_mode != DATA_MODE_VMALLOC))
                use_inline_bio(b, rw, block, end_io);
        else
                use_dmio(b, rw, block, end_io);
@@ -550,8 +559,6 @@ static void __write_dirty_buffer(struct
        clear_bit(B_DIRTY, &b->state);
        wait_on_bit_lock(&b->state, B_WRITING,
                         do_io_schedule, TASK_UNINTERRUPTIBLE);
-       if (b->c->write_callback)
-               b->c->write_callback(b);
        submit_io(b, WRITE, b->block, write_endio);
 }


This doesn't seem an improvement.  Except ... it changes the behaviour
of dm_bufio_release_move().  So was there a preexisting bug in
dm_bufio_release_move() that you're trying to fix with this patch?