From mboxrd@z Thu Jan 1 00:00:00 1970 From: Steven Whitehouse Date: Tue, 05 Nov 2013 11:04:00 +0000 Subject: [Cluster-devel] [GFS2 PATCH] GFS2: Drop inadequate rgrps from the reservation tree In-Reply-To: <1944013634.15902000.1383584035435.JavaMail.root@redhat.com> References: <1944013634.15902000.1383584035435.JavaMail.root@redhat.com> Message-ID: <1383649440.2713.15.camel@menhir> List-Id: To: cluster-devel.redhat.com MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Hi, Looks good. Thanks, Steve. On Mon, 2013-11-04 at 11:53 -0500, Bob Peterson wrote: > Hi, > > This patch fixes a bug in the GFS2 block allocation code. The problem > starts if a process already has a multi-block reservation, but for > some reason, another process disqualifies it from further allocations. > For example, the other process might set on the GFS2_RDF_ERROR bit. > The process holding the reservation jumps to label skip_rgrp, but > that label comes after the code that removes the reservation from the > tree. Therefore, the no longer usable reservation is not removed from > the rgrp's reservations tree; it's lost. Eventually, the lost reservation > causes the count of reserved blocks to get off, and eventually that > causes a BUG_ON(rs->rs_rbm.rgd->rd_reserved < rs->rs_free) to trigger. > This patch moves the call to after label skip_rgrp so that the > disqualified reservation is properly removed from the tree, thus keeping > the rgrp rd_reserved count sane. > > Regards, > > Bob Peterson > Red Hat File Systems > > Signed-off-by: Bob Peterson > --- > diff --git a/fs/gfs2/rgrp.c b/fs/gfs2/rgrp.c > index 711e835..ddcddce 100644 > --- a/fs/gfs2/rgrp.c > +++ b/fs/gfs2/rgrp.c > @@ -1949,15 +1949,16 @@ int gfs2_inplace_reserve(struct gfs2_inode *ip, const struct gfs2_alloc_parms *a > return 0; > } > > - /* Drop reservation, if we couldn't use reserved rgrp */ > - if (gfs2_rs_active(rs)) > - gfs2_rs_deltree(rs); > check_rgrp: > /* Check for unlinked inodes which can be reclaimed */ > if (rs->rs_rbm.rgd->rd_flags & GFS2_RDF_CHECK) > try_rgrp_unlink(rs->rs_rbm.rgd, &last_unlinked, > ip->i_no_addr); > skip_rgrp: > + /* Drop reservation, if we couldn't use reserved rgrp */ > + if (gfs2_rs_active(rs)) > + gfs2_rs_deltree(rs); > + > /* Unlock rgrp if required */ > if (!rg_locked) > gfs2_glock_dq_uninit(&rs->rs_rgd_gh); >