From patchwork Tue Feb 28 23:36:08 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Goldwyn Rodrigues X-Patchwork-Id: 9597163 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id C2CAE60429 for ; Wed, 1 Mar 2017 00:01:31 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id B4A7D277D9 for ; Wed, 1 Mar 2017 00:01:31 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id A992F27FB1; Wed, 1 Mar 2017 00:01:31 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 42085277D9 for ; Wed, 1 Mar 2017 00:01:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752019AbdCAAB2 (ORCPT ); Tue, 28 Feb 2017 19:01:28 -0500 Received: from mx2.suse.de ([195.135.220.15]:52387 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751593AbdB1X7y (ORCPT ); Tue, 28 Feb 2017 18:59:54 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay1.suse.de (charybdis-ext.suse.de [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 56993AC89; Tue, 28 Feb 2017 23:36:49 +0000 (UTC) From: Goldwyn Rodrigues To: jack@suse.com Cc: hch@infradead.org, linux-fsdevel@vger.kernel.org, linux-block@vger.kernel.org, linux-btrfs@vger.kernel.org, linux-ext4@vger.kernel.org, linux-xfs@vger.kernel.org, Goldwyn Rodrigues Subject: [PATCH 6/8] nowait aio: ext4 Date: Tue, 28 Feb 2017 17:36:08 -0600 Message-Id: <20170228233610.25456-7-rgoldwyn@suse.de> X-Mailer: git-send-email 2.10.2 In-Reply-To: <20170228233610.25456-1-rgoldwyn@suse.de> References: <20170228233610.25456-1-rgoldwyn@suse.de> Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Goldwyn Rodrigues Return EAGAIN if any of the following checks fail for direct I/O: + i_rwsem is lockable + Writing beyond end of file (will trigger allocation) + Blocks are not allocated at the write location Signed-off-by: Goldwyn Rodrigues --- fs/ext4/file.c | 53 +++++++++++++++++++++++++++++++++++------------------ 1 file changed, 35 insertions(+), 18 deletions(-) diff --git a/fs/ext4/file.c b/fs/ext4/file.c index d663d3d..391e03b 100644 --- a/fs/ext4/file.c +++ b/fs/ext4/file.c @@ -124,27 +124,22 @@ ext4_unaligned_aio(struct inode *inode, struct iov_iter *from, loff_t pos) return 0; } -/* Is IO overwriting allocated and initialized blocks? */ -static bool ext4_overwrite_io(struct inode *inode, loff_t pos, loff_t len) +/* Are IO blocks allocated */ +static bool ext4_blocks_mapped(struct inode *inode, loff_t pos, loff_t len, + struct ext4_map_blocks *map) { - struct ext4_map_blocks map; unsigned int blkbits = inode->i_blkbits; int err, blklen; if (pos + len > i_size_read(inode)) return false; - map.m_lblk = pos >> blkbits; - map.m_len = EXT4_MAX_BLOCKS(len, pos, blkbits); - blklen = map.m_len; + map->m_lblk = pos >> blkbits; + map->m_len = EXT4_MAX_BLOCKS(len, pos, blkbits); + blklen = map->m_len; - err = ext4_map_blocks(NULL, inode, &map, 0); - /* - * 'err==len' means that all of the blocks have been preallocated, - * regardless of whether they have been initialized or not. To exclude - * unwritten extents, we need to check m_flags. - */ - return err == blklen && (map.m_flags & EXT4_MAP_MAPPED); + err = ext4_map_blocks(NULL, inode, map, 0); + return err == blklen; } static ssize_t ext4_write_checks(struct kiocb *iocb, struct iov_iter *from) @@ -176,6 +171,7 @@ ext4_dax_write_iter(struct kiocb *iocb, struct iov_iter *from) struct inode *inode = file_inode(iocb->ki_filp); ssize_t ret; bool overwrite = false; + struct ext4_map_blocks map; inode_lock(inode); ret = ext4_write_checks(iocb, from); @@ -188,7 +184,9 @@ ext4_dax_write_iter(struct kiocb *iocb, struct iov_iter *from) if (ret) goto out; - if (ext4_overwrite_io(inode, iocb->ki_pos, iov_iter_count(from))) { + if (ext4_blocks_mapped(inode, iocb->ki_pos, + iov_iter_count(from), &map) && + (map.m_flags & EXT4_MAP_MAPPED)) { overwrite = true; downgrade_write(&inode->i_rwsem); } @@ -209,6 +207,7 @@ ext4_file_write_iter(struct kiocb *iocb, struct iov_iter *from) { struct inode *inode = file_inode(iocb->ki_filp); int o_direct = iocb->ki_flags & IOCB_DIRECT; + int nowait = iocb->ki_flags & IOCB_NOWAIT; int unaligned_aio = 0; int overwrite = 0; ssize_t ret; @@ -218,7 +217,13 @@ ext4_file_write_iter(struct kiocb *iocb, struct iov_iter *from) return ext4_dax_write_iter(iocb, from); #endif - inode_lock(inode); + if (o_direct && nowait) { + if (!inode_trylock(inode)) + return -EAGAIN; + } else { + inode_lock(inode); + } + ret = ext4_write_checks(iocb, from); if (ret <= 0) goto out; @@ -237,9 +242,21 @@ ext4_file_write_iter(struct kiocb *iocb, struct iov_iter *from) iocb->private = &overwrite; /* Check whether we do a DIO overwrite or not */ - if (o_direct && ext4_should_dioread_nolock(inode) && !unaligned_aio && - ext4_overwrite_io(inode, iocb->ki_pos, iov_iter_count(from))) - overwrite = 1; + if (o_direct && !unaligned_aio) { + struct ext4_map_blocks map; + if (ext4_blocks_mapped(inode, iocb->ki_pos, + iov_iter_count(from), &map)) { + /* To exclude unwritten extents, we need to check + * m_flags. + */ + if (ext4_should_dioread_nolock(inode) && + (map.m_flags & EXT4_MAP_MAPPED)) + overwrite = 1; + } else if (iocb->ki_flags & IOCB_NOWAIT) { + ret = -EAGAIN; + goto out; + } + } ret = __generic_file_write_iter(iocb, from); inode_unlock(inode);