From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bob Peterson Date: Mon, 4 Nov 2013 11:53:55 -0500 (EST) Subject: [Cluster-devel] [GFS2 PATCH] GFS2: Drop inadequate rgrps from the reservation tree In-Reply-To: <638877571.15901094.1383583999843.JavaMail.root@redhat.com> Message-ID: <1944013634.15902000.1383584035435.JavaMail.root@redhat.com> List-Id: To: cluster-devel.redhat.com MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit 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);