On Mon, 2008-06-02 at 12:05 +0530, Aneesh Kumar K.V wrote: > On Sun, Jun 01, 2008 at 10:38:35PM -0700, Mingming Cao wrote: > > On Mon, 2008-06-02 at 09:39 +0530, Aneesh Kumar K.V wrote: > > > On Sun, Jun 01, 2008 at 08:50:32PM -0700, Mingming Cao wrote: > > > > On Mon, 2008-06-02 at 08:44 +0530, Aneesh Kumar K.V wrote: > > > > > On Sun, Jun 01, 2008 at 02:10:02PM -0700, Mingming Cao wrote: > > > > > > ext4: Need clear buffer_delay after page writeout for delayed allocation > > > > > > > > > > > > From: Mingming Cao <cmm@xxxxxxxxxx> > > > > > > > > > > > > Need clear buffer_delay in ext4_da_writepage() after page has been writeout > > > > > > > > > > > > Signed-off-by: Mingming Cao <cmm@xxxxxxxxxx> > > > > > > > > > > > > --- > > > > > > > > > > We do that in mpage_put_bnr_to_bhs. > > > > > > > > > Normally delayed buffer could be cleared in that case, but if allocation > > > > failed in __mapge_da_writepages(), it will keep buffer_delay marked and > > > > deferring to later ext4_da_writepage() to do block allocation. This > > > > patch handles clear bh delay bit in this case. > > > > > > > > > > Why not do it in ext4_da_get_block_write then. > > > > The buffer head passed to ext4_da_get_block_write() calling from > > mpage_da_map_blocks is a dummy one, to store the allocated extent, not > > the bh that need map. > > > ie true when ext4_da_get_block_write is called via writepages. In > that case mpage_put_bnr_to_bhs clears the delay bit properly. How about > the changes below. > I see your patch below is trying to address how to detect and assign blocks with your suggestion(i.e clear delayed bit in get_block). But I don;t think it's needed. My last email I mean the buffer head new in mpage_da_map_blocks() is a dummy bh, the real buffer head lbh is not passed to get_block. We could clear the delayed bit on successful return of get_block, mpage_put_bnr_to_bhs() ignore that dummy bh anyway. But that seems twisted, unccessary. I still think clear the bit in the ext4_da_write_page() is more clean way. the original patch clears the delayed bit on success case. For the error case I think we could handle properly by only clear the delayed bit if buffer is mapped. Mingming > > diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c > index 26f3626..9d25255 100644 > --- a/fs/ext4/extents.c > +++ b/fs/ext4/extents.c > @@ -2873,6 +2873,7 @@ int ext4_ext_get_blocks(handle_t *handle, struct inode *inode, > allocated = max_blocks; > ext4_ext_show_leaf(inode, path); > __set_bit(BH_Mapped, &bh_result->b_state); > + __clear_bit(BH_Delay, &bh_result->b_state); > bh_result->b_bdev = inode->i_sb->s_bdev; > bh_result->b_blocknr = newblock; > out2: > diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c > index 2194aa7..2a2f832 100644 > --- a/fs/ext4/inode.c > +++ b/fs/ext4/inode.c > @@ -917,6 +917,7 @@ int ext4_get_blocks_handle(handle_t *handle, struct inode *inode, > goto cleanup; > > set_buffer_new(bh_result); > + clear_buffer_delay(bh_result); > got_it: > map_bh(bh_result, inode->i_sb, le32_to_cpu(chain[depth-1].key)); > if (count > blocks_to_boundary) > diff --git a/fs/mpage.c b/fs/mpage.c > index c107728..0d05d7a 100644 > --- a/fs/mpage.c > +++ b/fs/mpage.c > @@ -897,6 +897,14 @@ static void mpage_da_map_blocks(struct mpage_da_data *mpd) > int err = 0, remain = lbh->b_size; > sector_t next = lbh->b_blocknr; > struct buffer_head new; > + int delay_buf = 0; > + > + /* > + * We clear the delay bit in get_block so remember > + * whether we are doing a delay allocation > + */ > + if (buffer_delay(lbh)) > + delay_buf = 1; > > /* > * We consider only non-mapped and non-allocated blocks > @@ -926,7 +934,7 @@ static void mpage_da_map_blocks(struct mpage_da_data *mpd) > * If blocks are delayed marked, we need to > * put actual blocknr and drop delayed bit > */ > - if (buffer_delay(lbh)) > + if (delay_buf) > mpage_put_bnr_to_bhs(mpd, next, &new); > > /* go for the remaining blocks */ > -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
