From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from bombadil.infradead.org ([198.137.202.133]:35854 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728983AbeKJVgD (ORCPT ); Sat, 10 Nov 2018 16:36:03 -0500 Received: from 089144211136.atnat0020.highway.a1.net ([89.144.211.136] helo=localhost) by bombadil.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1gLRnJ-0000WA-HU for linux-xfs@vger.kernel.org; Sat, 10 Nov 2018 11:51:18 +0000 From: Christoph Hellwig Subject: [PATCH 2/3] xfs: merge COW handling into xfs_file_iomap_begin_delay Date: Sat, 10 Nov 2018 12:51:03 +0100 Message-Id: <20181110115104.30293-3-hch@lst.de> In-Reply-To: <20181110115104.30293-1-hch@lst.de> References: <20181110115104.30293-1-hch@lst.de> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-xfs-owner@vger.kernel.org List-ID: List-Id: xfs To: linux-xfs@vger.kernel.org Besides simplifying the code a bit this allows to actually implement the behavior of using COW preallocation for non-COW data mentioned in the current comments. Note that this breaks the current version of xfs/420, but that is because the test is broken. A separate fix will be sent for it. Signed-off-by: Christoph Hellwig --- fs/xfs/xfs_iomap.c | 135 +++++++++++++++++++++++++++++-------------- fs/xfs/xfs_reflink.c | 66 --------------------- 2 files changed, 92 insertions(+), 109 deletions(-) diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c index f982b183e05b..3e7f0ca78669 100644 --- a/fs/xfs/xfs_iomap.c +++ b/fs/xfs/xfs_iomap.c @@ -522,15 +522,16 @@ xfs_file_iomap_begin_delay( { struct xfs_inode *ip = XFS_I(inode); struct xfs_mount *mp = ip->i_mount; - struct xfs_ifork *ifp = XFS_IFORK_PTR(ip, XFS_DATA_FORK); xfs_fileoff_t offset_fsb = XFS_B_TO_FSBT(mp, offset); xfs_fileoff_t maxbytes_fsb = XFS_B_TO_FSB(mp, mp->m_super->s_maxbytes); xfs_fileoff_t end_fsb; - int error = 0, eof = 0; - struct xfs_bmbt_irec got; - struct xfs_iext_cursor icur; + struct xfs_bmbt_irec imap, cmap; + struct xfs_iext_cursor icur, ccur; xfs_fsblock_t prealloc_blocks = 0; + bool eof = false, cow_eof = false, shared; + int whichfork = XFS_DATA_FORK; + int error = 0; ASSERT(!XFS_IS_REALTIME_INODE(ip)); ASSERT(!xfs_get_extsz_hint(ip)); @@ -548,7 +549,7 @@ xfs_file_iomap_begin_delay( XFS_STATS_INC(mp, xs_blk_mapw); - if (!(ifp->if_flags & XFS_IFEXTENTS)) { + if (!(ip->i_df.if_flags & XFS_IFEXTENTS)) { error = xfs_iread_extents(NULL, ip, XFS_DATA_FORK); if (error) goto out_unlock; @@ -556,51 +557,97 @@ xfs_file_iomap_begin_delay( end_fsb = min(XFS_B_TO_FSB(mp, offset + count), maxbytes_fsb); - eof = !xfs_iext_lookup_extent(ip, ifp, offset_fsb, &icur, &got); + /* + * Search the data fork fork first to look up our source mapping. We + * always need the data fork map, as we have to return it to the + * iomap code so that the higher level write code can read data in to + * perform read-modify-write cycles for unaligned writes. + */ + eof = !xfs_iext_lookup_extent(ip, &ip->i_df, offset_fsb, &icur, &imap); if (eof) - got.br_startoff = end_fsb; /* fake hole until the end */ + imap.br_startoff = end_fsb; /* fake hole until the end */ - if (got.br_startoff <= offset_fsb) { + /* We never need to allocate blocks for zeroing a hole. */ + if ((flags & IOMAP_ZERO) && imap.br_startoff > offset_fsb) { + xfs_hole_to_iomap(ip, iomap, offset_fsb, imap.br_startoff); + goto out_unlock; + } + + /* + * Search the COW fork extent list even if we did not find a data fork + * extent. This serves two purposes: first this implements the + * speculative preallocation using cowextisze, so that we also unshare + * block adjacent to shared blocks instead of just the shared blocks + * themselves. Second the lookup in the extent list is generally faster + * than going out to the shared extent tree. + */ + if (xfs_is_reflink_inode(ip)) { + cow_eof = !xfs_iext_lookup_extent(ip, ip->i_cowfp, offset_fsb, + &ccur, &cmap); + if (!cow_eof && cmap.br_startoff <= offset_fsb) { + if (imap.br_startoff <= offset_fsb) { + xfs_trim_extent(&imap, cmap.br_startoff, + cmap.br_blockcount); + } else { + xfs_trim_extent(&cmap, offset_fsb, + imap.br_startoff - offset_fsb); + imap = cmap; + } + trace_xfs_reflink_cow_found(ip, &imap); + goto done; + } + } + + if (imap.br_startoff <= offset_fsb) { /* * For reflink files we may need a delalloc reservation when * overwriting shared extents. This includes zeroing of * existing extents that contain data. */ - if (xfs_is_reflink_inode(ip) && - ((flags & IOMAP_WRITE) || - got.br_state != XFS_EXT_UNWRITTEN)) { - xfs_trim_extent(&got, offset_fsb, end_fsb - offset_fsb); - error = xfs_reflink_reserve_cow(ip, &got); - if (error) - goto out_unlock; + if (!xfs_is_reflink_inode(ip) || + ((flags & IOMAP_ZERO) && imap.br_state != XFS_EXT_NORM)) { + trace_xfs_iomap_found(ip, offset, count, 0, &imap); + goto done; } - trace_xfs_iomap_found(ip, offset, count, 0, &got); - goto done; - } + xfs_trim_extent(&imap, offset_fsb, end_fsb - offset_fsb); - if (flags & IOMAP_ZERO) { - xfs_hole_to_iomap(ip, iomap, offset_fsb, got.br_startoff); - goto out_unlock; + /* Trim the mapping to the nearest shared extent boundary. */ + error = xfs_reflink_trim_around_shared(ip, &imap, &shared); + if (error) + goto out_unlock; + + /* Not shared? Just report the (potentially capped) extent. */ + if (!shared) { + trace_xfs_iomap_found(ip, offset, count, 0, &imap); + goto done; + } + + /* + * Fork all the shared blocks from our write offset until the + * end of the extent. + */ + whichfork = XFS_COW_FORK; + end_fsb = imap.br_startoff + imap.br_blockcount; + } else { + /* + * We cap the maximum length we map here to MAX_WRITEBACK_PAGES + * pages to keep the chunks of work done where somewhat + * symmetric with the work writeback does. This is a completely + * arbitrary number pulled out of thin air. + * + * Note that the values needs to be less than 32-bits wide until + * the lower level functions are updated. + */ + count = min_t(loff_t, count, 1024 * PAGE_SIZE); + end_fsb = min(XFS_B_TO_FSB(mp, offset + count), maxbytes_fsb); } error = xfs_qm_dqattach_locked(ip, false); if (error) goto out_unlock; - /* - * We cap the maximum length we map here to MAX_WRITEBACK_PAGES pages - * to keep the chunks of work done where somewhat symmetric with the - * work writeback does. This is a completely arbitrary number pulled - * out of thin air as a best guess for initial testing. - * - * Note that the values needs to be less than 32-bits wide until - * the lower level functions are updated. - */ - count = min_t(loff_t, count, 1024 * PAGE_SIZE); - end_fsb = min(XFS_B_TO_FSB(mp, offset + count), maxbytes_fsb); - - if (eof) { + if (eof && whichfork == XFS_DATA_FORK) { prealloc_blocks = xfs_iomap_prealloc_size(ip, offset, count, &icur); if (prealloc_blocks) { @@ -623,9 +670,11 @@ xfs_file_iomap_begin_delay( } retry: - error = xfs_bmapi_reserve_delalloc(ip, XFS_DATA_FORK, offset_fsb, - end_fsb - offset_fsb, prealloc_blocks, &got, &icur, - eof); + error = xfs_bmapi_reserve_delalloc(ip, whichfork, offset_fsb, + end_fsb - offset_fsb, prealloc_blocks, + whichfork == XFS_DATA_FORK ? &imap : &cmap, + whichfork == XFS_DATA_FORK ? &icur : &ccur, + whichfork == XFS_DATA_FORK ? eof : cow_eof); switch (error) { case 0: break; @@ -647,18 +696,18 @@ xfs_file_iomap_begin_delay( * them out if the write happens to fail. */ iomap->flags |= IOMAP_F_NEW; - trace_xfs_iomap_alloc(ip, offset, count, 0, &got); + trace_xfs_iomap_alloc(ip, offset, count, 0, &imap); done: - if (isnullstartblock(got.br_startblock)) - got.br_startblock = DELAYSTARTBLOCK; + if (isnullstartblock(imap.br_startblock)) + imap.br_startblock = DELAYSTARTBLOCK; - if (!got.br_startblock) { - error = xfs_alert_fsblock_zero(ip, &got); + if (!imap.br_startblock) { + error = xfs_alert_fsblock_zero(ip, &imap); if (error) goto out_unlock; } - xfs_bmbt_to_iomap(ip, iomap, &got); + xfs_bmbt_to_iomap(ip, iomap, &imap); out_unlock: xfs_iunlock(ip, XFS_ILOCK_EXCL); diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c index 31d7c3e62bbc..6a002f024349 100644 --- a/fs/xfs/xfs_reflink.c +++ b/fs/xfs/xfs_reflink.c @@ -234,72 +234,6 @@ xfs_reflink_trim_around_shared( } } -/* - * Trim the passed in imap to the next shared/unshared extent boundary, and - * if imap->br_startoff points to a shared extent reserve space for it in the - * COW fork. - * - * Note that imap will always contain the block numbers for the existing blocks - * in the data fork, as the upper layers need them for read-modify-write - * operations. - */ -int -xfs_reflink_reserve_cow( - struct xfs_inode *ip, - struct xfs_bmbt_irec *imap) -{ - struct xfs_ifork *ifp = XFS_IFORK_PTR(ip, XFS_COW_FORK); - struct xfs_bmbt_irec got; - int error = 0; - bool eof = false; - struct xfs_iext_cursor icur; - bool shared; - - /* - * Search the COW fork extent list first. This serves two purposes: - * first this implement the speculative preallocation using cowextisze, - * so that we also unshared block adjacent to shared blocks instead - * of just the shared blocks themselves. Second the lookup in the - * extent list is generally faster than going out to the shared extent - * tree. - */ - - if (!xfs_iext_lookup_extent(ip, ifp, imap->br_startoff, &icur, &got)) - eof = true; - if (!eof && got.br_startoff <= imap->br_startoff) { - trace_xfs_reflink_cow_found(ip, imap); - xfs_trim_extent(imap, got.br_startoff, got.br_blockcount); - return 0; - } - - /* Trim the mapping to the nearest shared extent boundary. */ - error = xfs_reflink_trim_around_shared(ip, imap, &shared); - if (error) - return error; - - /* Not shared? Just report the (potentially capped) extent. */ - if (!shared) - return 0; - - /* - * Fork all the shared blocks from our write offset until the end of - * the extent. - */ - error = xfs_qm_dqattach_locked(ip, false); - if (error) - return error; - - error = xfs_bmapi_reserve_delalloc(ip, XFS_COW_FORK, imap->br_startoff, - imap->br_blockcount, 0, &got, &icur, eof); - if (error == -ENOSPC || error == -EDQUOT) - trace_xfs_reflink_cow_enospc(ip, imap); - if (error) - return error; - - trace_xfs_reflink_cow_alloc(ip, &got); - return 0; -} - /* Convert part of an unwritten CoW extent to a real one. */ STATIC int xfs_reflink_convert_cow_extent( -- 2.19.1