Messages in this thread | | | Date | Thu, 26 Mar 2009 11:35:29 -0700 | From | Andrew Morton <> | Subject | Re: ext3 IO latency measurements (was: Linux 2.6.29) |
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The patch looks OK to me.
On Thu, 26 Mar 2009 19:11:06 +0100 Jan Kara <jack@suse.cz> wrote:
> @@ -1490,6 +1494,16 @@ static int ext3_ordered_writepage(struct page *page, > if (ext3_journal_current_handle()) > goto out_fail; > > + if (!page_has_buffers(page)) { > + create_empty_buffers(page, inode->i_sb->s_blocksize, > + (1 << BH_Dirty)|(1 << BH_Uptodate));
This will attach dirty buffers to a clean page, which is an invalid state (but OK if we immediately fix it up).
> + } else if (!walk_page_buffers(NULL, page_buffers(page), 0, PAGE_CACHE_SIZE, NULL, buffer_unmapped)) { > + /* Provide NULL instead of get_block so that we catch bugs if buffers weren't really mapped */ > + return block_write_full_page(page, NULL, wbc); > + } > + page_bufs = page_buffers(page); > + > + > handle = ext3_journal_start(inode, ext3_writepage_trans_blocks(inode)); > > if (IS_ERR(handle)) {
And if this error happens we'll go on to run redirty_page_for_writepage() which will do the right thing.
However if PageMappedToDisk() is working right, we should be able to avoid that newly-added buffer walk. Possibly SetPageMappedToDisk() isn't being run in all the right places though, dunno.
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