From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bob Peterson Date: Wed, 6 Jul 2016 11:52:27 -0400 (EDT) Subject: [Cluster-devel] [GFS2 PATCH] GFS2: Check rs_free with rd_rsspin protection In-Reply-To: <323041035.7048186.1467820249716.JavaMail.zimbra@redhat.com> Message-ID: <1537255470.7048688.1467820347281.JavaMail.zimbra@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, For the last process to close a file opened for write, function gfs2_rsqa_delete was deleting the file's inode's block reservation out of the rgrp reservations tree. Then it was checking to make sure rs_free was 0, but it was performing the check outside the protection of rd_rsspin spin_lock. The rd_rsspin spin_lock protection is needed to prevent a race between the process freeing the reservation and another who is allocating a new set of blocks inside the same rgrp for the same inode, thus changing its value. Signed-off-by: Bob Peterson Regards, Bob Peterson Red Hat File Systems --- diff --git a/fs/gfs2/rgrp.c b/fs/gfs2/rgrp.c index fba38ca..86ccc015 100644 --- a/fs/gfs2/rgrp.c +++ b/fs/gfs2/rgrp.c @@ -658,6 +658,7 @@ void gfs2_rs_deltree(struct gfs2_blkreserv *rs) if (rgd) { spin_lock(&rgd->rd_rsspin); __rs_deltree(rs); + BUG_ON(rs->rs_free); spin_unlock(&rgd->rd_rsspin); } } @@ -671,10 +672,8 @@ void gfs2_rs_deltree(struct gfs2_blkreserv *rs) void gfs2_rsqa_delete(struct gfs2_inode *ip, atomic_t *wcount) { down_write(&ip->i_rw_mutex); - if ((wcount == NULL) || (atomic_read(wcount) <= 1)) { + if ((wcount == NULL) || (atomic_read(wcount) <= 1)) gfs2_rs_deltree(&ip->i_res); - BUG_ON(ip->i_res.rs_free); - } up_write(&ip->i_rw_mutex); gfs2_qa_delete(ip, wcount); }