On Sun, Apr 10, 2011 at 10:30:13PM +0800, Yongqiang Yang wrote:
> So the right code should beï
>
> bh->b_state = (bh->b_state & ~EXT4_MAP_FLAGS) | map.m_flags;
> map_bh(bh, inode->i_sb, map.m_pblk);
> if (buffer_unwritten(bh)) {
> /* A delayed write to unwritten bh should be marked
> * new and mapped. Mapped ensures that we don't do
> * get_block multiple times when we write to the same
> * offset and new ensures that we do proper zero out
> * for partial write.
> */
> set_buffer_new(bh);
> }
Actually, I'm much more comfortable backing out commit 6de9843da
entirely. The above is *not* equivalent to what we had before ---
consider the case where ext4_map_blocks returns !EXT4_MAP_MAPPED &&
!EXT4_MAP_UNWRITTEN.
I don't *think* this should happen in the case where ext4_map_blocks
returns a value > 0, but the fact that it's not obvious, means I'd
much rather keep things the way that they are. It's not like dropping
the set_buffer_mapped(bh) was saving anything measurable anyway....
- Ted
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