From: Andreas Gruenbacher agruenba@redhat.com
[ Upstream commit f4e2f5e1a527ce58fc9f85145b03704779a3123e ]
This patch rearranges gfs2_add_revoke so that the extra glock reference is added earlier on in the function to avoid races in which the glock is freed before the new reference is taken.
Signed-off-by: Andreas Gruenbacher agruenba@redhat.com Signed-off-by: Bob Peterson rpeterso@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/gfs2/log.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/fs/gfs2/log.c b/fs/gfs2/log.c index 60d911e293e6..2674feda1d7a 100644 --- a/fs/gfs2/log.c +++ b/fs/gfs2/log.c @@ -603,13 +603,13 @@ void gfs2_add_revoke(struct gfs2_sbd *sdp, struct gfs2_bufdata *bd) struct buffer_head *bh = bd->bd_bh; struct gfs2_glock *gl = bd->bd_gl;
+ sdp->sd_log_num_revoke++; + if (atomic_inc_return(&gl->gl_revokes) == 1) + gfs2_glock_hold(gl); bh->b_private = NULL; bd->bd_blkno = bh->b_blocknr; gfs2_remove_from_ail(bd); /* drops ref on bh */ bd->bd_bh = NULL; - sdp->sd_log_num_revoke++; - if (atomic_inc_return(&gl->gl_revokes) == 1) - gfs2_glock_hold(gl); set_bit(GLF_LFLUSH, &gl->gl_flags); list_add(&bd->bd_list, &sdp->sd_log_revokes); }