On Thu, Jan 07, 2016 at 10:31:27AM +1100, Dave Chinner wrote: > From: Dave Chinner <dchinner@xxxxxxxxxx> > > For large sparse or fragmented files, checking every single entry in > the bmapbt on every operation is prohibitively expensive. Especially > as such checks rarely discover problems during normal operations on > high extent coutn files. Our regression tests don't tend to exercise count > files with hundreds of thousands to millions of extents, so mostly > this isn't noticed. > > However, trying to run things like xfs_mdrestore of large filesystem > dumps on a debug kernel quickly becomes impossible as the CPU is > completely burnt up repeatedly walking the sparse file bmapbt that > is generated for every allocation that is made. > > Hence, if the file has more than 10,000 extents, just don't bother > with walking the tree to check it exhaustively. The btree code has > checks that ensure that the newly inserted/removed/modified record > is correctly ordered, so the entrie tree walk in thses cases has these > limited additional value. > > Signed-off-by: Dave Chinner <dchinner@xxxxxxxxxx> > --- > fs/xfs/libxfs/xfs_bmap.c | 10 ++++++++-- > 1 file changed, 8 insertions(+), 2 deletions(-) > > diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c > index 7388495..bc7e7d5 100644 > --- a/fs/xfs/libxfs/xfs_bmap.c > +++ b/fs/xfs/libxfs/xfs_bmap.c > @@ -325,9 +325,11 @@ xfs_check_block( > > /* > * Check that the extents for the inode ip are in the right order in all > - * btree leaves. > + * btree leaves. THis becomes prohibitively expensive for large extent count This Reviewed-by: Brian Foster <bfoster@xxxxxxxxxx> > + * files, so don't bother with inodes that have more than 10,000 extents in > + * them. The btree record ordering checks will still be done, so for such large > + * bmapbt constructs that is going to catch most corruptions. > */ > - > STATIC void > xfs_bmap_check_leaf_extents( > xfs_btree_cur_t *cur, /* btree cursor or null */ > @@ -352,6 +354,10 @@ xfs_bmap_check_leaf_extents( > return; > } > > + /* skip large extent count inodes */ > + if (ip->i_d.di_nextents > 10000) > + return; > + > bno = NULLFSBLOCK; > mp = ip->i_mount; > ifp = XFS_IFORK_PTR(ip, whichfork); > -- > 2.5.0 > > _______________________________________________ > xfs mailing list > xfs@xxxxxxxxxxx > http://oss.sgi.com/mailman/listinfo/xfs _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
