On Tue, Mar 17, 2009 at 06:33:54PM +0100, Jan Kara wrote: > Assume the following situation: > Filesystem with blocksize < pagesize - suppose blocksize = 1024, > pagesize = 4096. File 'f' has first four blocks already allocated. > (line with "state:" contains the state of buffers in the page - m = mapped, > u = uptodate, d = dirty) > > process 1: process 2: > > write to 'f' bytes 0 - 1024 > state: |mud,-,-,-|, page dirty > write to 'f' bytes 1024 - 4096: > __block_prepare_write() maps blocks > state: |mud,m,m,m|, page dirty > we fail to copy data -> copied = 0 > block_write_end() does nothing > page gets unlocked If copied = 0 then in block_write_end we do page_zero_new_buffers(page, start+copied, start+len which would mean we should not see garbage. > writepage() is called on the page > block_write_full_page() writes buffers with garbage > -aneesh -- 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
