On Thu, 2008-05-22 at 15:55 +0530, Aneesh Kumar K.V wrote:
> On Wed, May 21, 2008 at 11:14:17PM +0530, Aneesh Kumar K.V wrote:
> > Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
> > ---
> > fs/ext4/inode.c | 10 +++++++---
> > 1 files changed, 7 insertions(+), 3 deletions(-)
> >
> > diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
> > index 46cc610..076d00f 100644
> > --- a/fs/ext4/inode.c
> > +++ b/fs/ext4/inode.c
> > @@ -1571,13 +1571,17 @@ static int ext4_da_writepages(struct address_space *mapping,
> > */
> > if (wbc->nr_to_write > EXT4_MAX_WRITEBACK_PAGES)
> > wbc->nr_to_write = EXT4_MAX_WRITEBACK_PAGES;
> > - to_write -= wbc->nr_to_write;
> >
> > + to_write -= wbc->nr_to_write;
> > ret = mpage_da_writepages(mapping, wbc, ext4_da_get_block_write);
> > ext4_journal_stop(handle);
> > - to_write +=wbc->nr_to_write;
> > + if (wbc->nr_to_write) {
> > + /* We failed to write what we requested for */
> > + to_write += wbc->nr_to_write;
> > + break;
> > + }
> > + wbc->nr_to_write = to_write;
> > }
> > -
> > out_writepages:
> > wbc->nr_to_write = to_write;
> > wbc->range_cyclic = range_cyclic;
>
> We need related fix for ext4_da_writepage. We need to allocate blocks in
> ext4_da_writepage and we are called with page_lock. The handle
> will be NULL in the below case and that would result in
> ext4_get_block starting a new transaction when allocating blocks.
>
Hi Aneesh, the blocks are not allocated at ext4_da_writepage() time,
the block allocation has been done in this path:
ext4_da_writepages()->mpage_da_writepages()->write_cache_pages()->
__mpage_da_writepage()->mpage_da_map_blocks() will ensure blocks are all
mapped before mpage_da_submit_io() calling
__mpage_writepage()->ext4_da_writepage() to submit the IO.
>
> static int __ext4_da_writepage(struct page *page,
> struct writeback_control *wbc)
> {
> struct inode *inode = page->mapping->host;
> handle_t *handle = NULL;
> int ret = 0;
>
> handle = ext4_journal_current_handle();
>
> if (test_opt(inode->i_sb, NOBH) && ext4_should_writeback_data(inode))
> ret = nobh_writepage(page, ext4_get_block, wbc);
> else
> ret = block_write_full_page(page, ext4_get_block, wbc);
>
> if (!ret && inode->i_size > EXT4_I(inode)->i_disksize) {
> EXT4_I(inode)->i_disksize = inode->i_size;
> ext4_mark_inode_dirty(handle, inode);
> }
>
> return ret;
> }
>
> -aneesh
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