From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from aserp1040.oracle.com ([141.146.126.69]:18492 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754135AbcHBWng (ORCPT ); Tue, 2 Aug 2016 18:43:36 -0400 Date: Tue, 2 Aug 2016 15:43:25 -0700 From: "Darrick J. Wong" To: Brian Foster Cc: david@fromorbit.com, linux-fsdevel@vger.kernel.org, vishal.l.verma@intel.com, xfs@oss.sgi.com Subject: Re: [PATCH 19/47] xfs: add tracepoints and error injection for deferred extent freeing Message-ID: <20160802224325.GN8590@birch.djwong.org> References: <146907695530.25461.3225785294902719773.stgit@birch.djwong.org> <146907709074.25461.17602977707506082040.stgit@birch.djwong.org> <20160802184800.GB58152@bfoster.bfoster> <20160802202425.GK8590@birch.djwong.org> <20160802213816.GA8100@bfoster.bfoster> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160802213816.GA8100@bfoster.bfoster> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Tue, Aug 02, 2016 at 05:38:17PM -0400, Brian Foster wrote: > On Tue, Aug 02, 2016 at 01:24:25PM -0700, Darrick J. Wong wrote: > > On Tue, Aug 02, 2016 at 02:48:00PM -0400, Brian Foster wrote: > > > On Wed, Jul 20, 2016 at 09:58:10PM -0700, Darrick J. Wong wrote: > > > > Add a couple of tracepoints for the deferred extent free operation and > > > > a site for injecting errors while finishing the operation. This makes > > > > it easier to debug deferred ops and test log redo. > > > > > > > > Signed-off-by: Darrick J. Wong > > > > --- > > > > fs/xfs/libxfs/xfs_alloc.c | 7 +++++++ > > > > fs/xfs/libxfs/xfs_bmap.c | 2 ++ > > > > fs/xfs/xfs_error.h | 4 +++- > > > > fs/xfs/xfs_trace.h | 5 ++++- > > > > 4 files changed, 16 insertions(+), 2 deletions(-) > > > > > > > > > > > > diff --git a/fs/xfs/libxfs/xfs_alloc.c b/fs/xfs/libxfs/xfs_alloc.c > > > > index 5993f87..22ac3f1 100644 > > > > --- a/fs/xfs/libxfs/xfs_alloc.c > > > > +++ b/fs/xfs/libxfs/xfs_alloc.c > > > > @@ -2702,6 +2702,13 @@ xfs_free_extent( > > > > > > > > ASSERT(len != 0); > > > > > > > > + trace_xfs_bmap_free_deferred(mp, agno, 0, agbno, len); > > > > + > > > > > > Hmm, but the bmap code isn't the only caller here. I was thinking that > > > maybe we'd be better served by pushing these down into xfs_defer_add() > > > and friends, but I guess we don't necessarily have the extent > > > information at that layer. > > > > Correct, we don't. > > > > > How about we just rename these tracepoints to match the function names > > > so they don't confuse me in the future? :) > > > > I broke with the function name convention so that the entry and exit > > tracepoints to deferred items would all have names that easily matched > > wildcards to make my life easier: > > > > # trace-cmd record -e 'xfs_*_defer' -e 'xfs_*_deferred' -F ... > > > > The xfs_bmap_free_defer tp seems reasonable, but xfs_bmap_free_deferred > doesn't really make sense when called via other places where nothing has > been deferred. > > I'm not totally sure I follow what the goal is with this tracepoint wrt > to naming that the trace_xfs_defer_*() tracepoints don't already achieve > (combined with standard infrastructure tracepoints), but if the name is > important, we should at least put it somewhere where it's only triggered > via a deferred operation (e.g., xfs_extent_free_finish_item()). Crap, you're right, the tp is in the wrong place. xfs_trans_free_extent() it is. Might as well rename them to xfs_extent_free_defer* while I'm at it. --D > > > > > + if (XFS_TEST_ERROR(false, mp, > > > > + XFS_ERRTAG_FREE_EXTENT, > > > > + XFS_RANDOM_FREE_EXTENT)) > > > > + return -EIO; > > > > + > > > > error = xfs_free_extent_fix_freelist(tp, agno, &agbp); > > > > if (error) > > > > return error; > > > > diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c > > > > index 540a6b7..8e14ff4 100644 > > > > --- a/fs/xfs/libxfs/xfs_bmap.c > > > > +++ b/fs/xfs/libxfs/xfs_bmap.c > > > > @@ -596,6 +596,8 @@ xfs_bmap_add_free( > > > > new = kmem_zone_alloc(xfs_bmap_free_item_zone, KM_SLEEP); > > > > new->xefi_startblock = bno; > > > > new->xefi_blockcount = (xfs_extlen_t)len; > > > > + trace_xfs_bmap_free_defer(mp, XFS_FSB_TO_AGNO(mp, bno), 0, > > > > + XFS_FSB_TO_AGBNO(mp, bno), len); > > > > xfs_defer_add(dfops, XFS_DEFER_OPS_TYPE_FREE, &new->xefi_list); > > > > } > > > > > > > > diff --git a/fs/xfs/xfs_error.h b/fs/xfs/xfs_error.h > > > > index 2e4f67f..da6f951 100644 > > > > --- a/fs/xfs/xfs_error.h > > > > +++ b/fs/xfs/xfs_error.h > > > > @@ -90,7 +90,8 @@ extern void xfs_verifier_error(struct xfs_buf *bp); > > > > #define XFS_ERRTAG_STRATCMPL_IOERR 19 > > > > #define XFS_ERRTAG_DIOWRITE_IOERR 20 > > > > #define XFS_ERRTAG_BMAPIFORMAT 21 > > > > -#define XFS_ERRTAG_MAX 22 > > > > +#define XFS_ERRTAG_FREE_EXTENT 22 > > > > +#define XFS_ERRTAG_MAX 23 > > > > > > > > /* > > > > * Random factors for above tags, 1 means always, 2 means 1/2 time, etc. > > > > @@ -117,6 +118,7 @@ extern void xfs_verifier_error(struct xfs_buf *bp); > > > > #define XFS_RANDOM_STRATCMPL_IOERR (XFS_RANDOM_DEFAULT/10) > > > > #define XFS_RANDOM_DIOWRITE_IOERR (XFS_RANDOM_DEFAULT/10) > > > > #define XFS_RANDOM_BMAPIFORMAT XFS_RANDOM_DEFAULT > > > > +#define XFS_RANDOM_FREE_EXTENT 1 > > > > > > > > > > Why not XFS_RANDOM_DEFAULT? > > > > I don't want the injected redo errors going off at random -- I want to set > > one and have it go off the very next time we hit it. This way I can write > > the xfstests like so: > > > > mkfs/mount > > write to a file; sync > > set a logic bomb for the next time we free an extent > > truncate the file > > > > unmount > > check that xfs_repair grumbles about the dirty log > > mount > > check the file > > > > Were the free-extent bomb set to go off at XFS_RANDOM_DEFAULT intervals, it'd > > only have a 1/100 chance of triggering, which makes it harder to test. > > > > Ok. > > Brian > > > --D > > > > > > > > Brian > > > > > > > #ifdef DEBUG > > > > extern int xfs_error_test_active; > > > > diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h > > > > index a45b030..939caf5 100644 > > > > --- a/fs/xfs/xfs_trace.h > > > > +++ b/fs/xfs/xfs_trace.h > > > > @@ -2417,9 +2417,12 @@ DEFINE_DEFER_PENDING_EVENT(xfs_defer_pending_cancel); > > > > DEFINE_DEFER_PENDING_EVENT(xfs_defer_pending_finish); > > > > DEFINE_DEFER_PENDING_EVENT(xfs_defer_pending_abort); > > > > > > > > -DEFINE_PHYS_EXTENT_DEFERRED_EVENT(xfs_defer_phys_extent); > > > > DEFINE_MAP_EXTENT_DEFERRED_EVENT(xfs_defer_map_extent); > > > > > > > > +#define DEFINE_BMAP_FREE_DEFERRED_EVENT DEFINE_PHYS_EXTENT_DEFERRED_EVENT > > > > +DEFINE_BMAP_FREE_DEFERRED_EVENT(xfs_bmap_free_defer); > > > > +DEFINE_BMAP_FREE_DEFERRED_EVENT(xfs_bmap_free_deferred); > > > > + > > > > #endif /* _TRACE_XFS_H */ > > > > > > > > #undef TRACE_INCLUDE_PATH > > > > > > > > _______________________________________________ > > > > xfs mailing list > > > > xfs@oss.sgi.com > > > > http://oss.sgi.com/mailman/listinfo/xfs