Messages in this thread Patch in this message |  | | | Subject | Re: [patch] call truncate_inode_pages in the DIO fallback to buffered I/O path | | From | jmoyer@redhat ... | | Date | Wed, 11 Oct 2006 12:48:57 -0400 |
==> Regarding Re: [patch] call truncate_inode_pages in the DIO fallback to buffered I/O path; Andrew Morton <akpm@osdl.org> adds:
akpm> Patch is below. The end result looks like:
akpm> /* coalesce the iovecs and go direct-to-BIO for O_DIRECT */ akpm> if (unlikely(file->f_flags & O_DIRECT)) { akpm> loff_t endbyte; akpm> ssize_t written_buffered; akpm> written = generic_file_direct_write(iocb, iov, &nr_segs, pos, akpm> ppos, count, ocount); akpm> if (written < 0 || written == count) akpm> goto out; akpm> /* akpm> * direct-io write to a hole: fall through to buffered I/O akpm> * for completing the rest of the request. akpm> */ akpm> pos += written; akpm> count -= written; akpm> written_buffered = generic_file_buffered_write(iocb, iov, akpm> nr_segs, pos, ppos, count, akpm> written); akpm> /* akpm> * We need to ensure that the page cache pages are written to akpm> * disk and invalidated to preserve the expected O_DIRECT akpm> * semantics. akpm> */ akpm> endbyte = pos + written_buffered - 1; We probably want to handle the case where generic_file_buffered_write returns an error or nothing written.
akpm> err = do_sync_file_range(file, pos, endbyte, akpm> SYNC_FILE_RANGE_WAIT_BEFORE| akpm> SYNC_FILE_RANGE_WRITE| akpm> SYNC_FILE_RANGE_WAIT_AFTER); akpm> if (err == 0) { akpm> written += written_buffered; akpm> invalidate_mapping_pages(mapping, akpm> pos >> PAGE_CACHE_SHIFT, akpm> endbyte >> PAGE_CACHE_SHIFT); generic_file_buffered_write takes written as an argument, and returns that amount plus whatever it managed to write. As such, you don't want to add written_buffered to written. Instead, you want written = written_buffered. The endbyte calculation has to be altered in kind.
Incremental, locally tested patch attached. Comments are welcome as always. Once there is consensus, I'll send this off for testing with Oracle again.
-Jeff
--- linux-2.6.18.i686/mm/filemap.c.orig 2006-10-11 11:58:29.000000000 -0400 +++ linux-2.6.18.i686/mm/filemap.c 2006-10-11 12:31:11.000000000 -0400 @@ -2419,19 +2419,21 @@ __generic_file_aio_write_nolock(struct k written_buffered = generic_file_buffered_write(iocb, iov, nr_segs, pos, ppos, count, written); + if (written_buffered < 0 || written_buffered == written) + goto out; /* * We need to ensure that the page cache pages are written to * disk and invalidated to preserve the expected O_DIRECT * semantics. */ - endbyte = pos + written_buffered - 1; + endbyte = pos + written_buffered - written - 1; err = do_sync_file_range(file, pos, endbyte, SYNC_FILE_RANGE_WAIT_BEFORE| SYNC_FILE_RANGE_WRITE| SYNC_FILE_RANGE_WAIT_AFTER); if (err == 0) { - written += written_buffered; + written = written_buffered; invalidate_mapping_pages(mapping, pos >> PAGE_CACHE_SHIFT, endbyte >> PAGE_CACHE_SHIFT); - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
|  |