From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from userp1040.oracle.com ([156.151.31.81]:39502 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752915AbdJUA0l (ORCPT ); Fri, 20 Oct 2017 20:26:41 -0400 Date: Fri, 20 Oct 2017 17:26:37 -0700 From: "Darrick J. Wong" Subject: Re: [PATCH 13/15] xfs: don't rely on extent indices in xfs_bmap_collapse_extents Message-ID: <20171021002637.GG4755@magnolia> References: <20171019065942.18813-1-hch@lst.de> <20171019065942.18813-14-hch@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20171019065942.18813-14-hch@lst.de> Sender: linux-xfs-owner@vger.kernel.org List-ID: List-Id: xfs To: Christoph Hellwig Cc: linux-xfs@vger.kernel.org On Thu, Oct 19, 2017 at 08:59:40AM +0200, Christoph Hellwig wrote: > Rewrite xfs_bmap_collapse_extents so that we don't rely on extent indices > except for iterating over them. Not being able to iterate to the next > extent is a sufficient exit condition, and we don't need to do any extent > count games given that: > > a) we already flushed all delalloc extents past our start offset > before doing the operation > b) xfs_iext_count() includes delalloc extents anyway > > Signed-off-by: Christoph Hellwig Looks ok, Reviewed-by: Darrick J. Wong > --- > fs/xfs/libxfs/xfs_bmap.c | 54 +++++++++++------------------------------------- > 1 file changed, 12 insertions(+), 42 deletions(-) > > diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c > index 2de9458903b6..4c89fdacda90 100644 > --- a/fs/xfs/libxfs/xfs_bmap.c > +++ b/fs/xfs/libxfs/xfs_bmap.c > @@ -5626,8 +5626,6 @@ xfs_bmap_collapse_extents( > struct xfs_btree_cur *cur = NULL; > struct xfs_bmbt_irec got, prev; > xfs_extnum_t current_ext; > - xfs_extnum_t total_extents; > - xfs_extnum_t stop_extent; > xfs_fileoff_t new_startoff; > int error = 0; > int logflags = 0; > @@ -5658,52 +5656,31 @@ xfs_bmap_collapse_extents( > cur->bc_private.b.flags = 0; > } > > - /* > - * There may be delalloc extents in the data fork before the range we > - * are collapsing out, so we cannot use the count of real extents here. > - * Instead we have to calculate it from the incore fork. > - */ > - total_extents = xfs_iext_count(ifp); > - if (total_extents == 0) { > - *done = true; > - goto del_cursor; > - } > - > - /* > - * Look up the extent index for the fsb where we start shifting. We can > - * henceforth iterate with current_ext as extent list changes are locked > - * out via ilock. > - * > - * If next_fsb lies in a hole beyond which there are no extents we are > - * done. > - */ > if (!xfs_iext_lookup_extent(ip, ifp, *next_fsb, ¤t_ext, &got)) { > *done = true; > goto del_cursor; > } > XFS_WANT_CORRUPTED_RETURN(mp, !isnullstartblock(got.br_startblock)); > > - stop_extent = total_extents; > - if (current_ext >= stop_extent) { > - error = -EIO; > - goto del_cursor; > - } > - > new_startoff = got.br_startoff - offset_shift_fsb; > - if (current_ext) { > - xfs_iext_get_extent(ifp, current_ext - 1, &prev); > + if (xfs_iext_get_extent(ifp, current_ext - 1, &prev)) { > if (new_startoff < prev.br_startoff + prev.br_blockcount) { > error = -EINVAL; > goto del_cursor; > } > > - /* check whether to merge the extent or shift it down */ > if (xfs_bmse_can_merge(&prev, &got, offset_shift_fsb)) { > error = xfs_bmse_merge(ip, whichfork, offset_shift_fsb, > current_ext, &got, &prev, cur, > &logflags, dfops); > if (error) > goto del_cursor; > + > + /* update got after merge */ > + if (!xfs_iext_get_extent(ifp, current_ext, &got)) { > + *done = true; > + goto del_cursor; > + } > goto done; > } > } else { > @@ -5717,20 +5694,13 @@ xfs_bmap_collapse_extents( > cur, &logflags, dfops, new_startoff); > if (error) > goto del_cursor; > - current_ext++; > -done: > - /* > - * If there was an extent merge during the shift, the extent > - * count can change. Update the total and grade the next record. > - */ > - total_extents = xfs_iext_count(ifp); > - stop_extent = total_extents; > - if (current_ext == stop_extent) { > - *done = true; > - goto del_cursor; > + > + if (!xfs_iext_get_extent(ifp, ++current_ext, &got)) { > + *done = true; > + goto del_cursor; > } > - xfs_iext_get_extent(ifp, current_ext, &got); > > +done: > *next_fsb = got.br_startoff; > del_cursor: > if (cur) > -- > 2.14.1 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-xfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html