On Wed, 30 Aug 2006 11:35:44 -0500
"Gorka Guardiola" <[email protected]> wrote:
> I am trying to mark a buffer for async write, but I am having a race condition
> to unlock the buffer. I am doing.
>
> bh = getbmapst(bdev, nsect); //this function calls bread
> if (!bh) {
> printk(KERN_ALERT "I/O error, bitmap cannot be trusted\n");
> return -1;
> }
>
> lock_buffer(bh);
>
> byte = bh->b_data + byteoffset;
> *byte |= 1 << bitoffset;
> lock_page(bh->b_page);
> mark_page_accessed(bh->b_page);
> __set_page_dirty_nobuffers(bh->b_page);
> unlock_page(bh->b_page);
> set_buffer_uptodate(bh);
> mark_buffer_dirty(bh);
> mark_buffer_async_write(bh);
> unlock_buffer(bh);
> brelse(bh);
There are rather a lot of mistakes in there.
More like this:
lock_page(bh->b_page);
lock_buffer(bh);
byte = bh->b_data + byteoffset;
*byte |= 1 << bitoffset;
mark_buffer_dirty(bh);
unlock_buffer(bh);
flush_dcache_page(page);
unlock_page(page);
put_bh(bh);
now, the buffer is dirty and will be written back by pdflush, sync, etc.
If you really want to start async IO against that buffer now, do
ll_rw_block(WRITE, 1, &bh);
just before the final put_bh().
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]
