[Cluster-devel] [GFS2 v8 PATCH 02/22] gfs2: clear ail1 list when gfs2 withdraws

[Bob Peterson]

This patch fixes a bug in which function gfs2_log_flush can get into
an infinite loop when a gfs2 file system is withdrawn. The problem
is the infinite loop "for (;;)" in gfs2_log_flush which would never
finish because the io error and subsequent withdraw prevented the
items from being taken off the ail list.

This patch tries to clean up the mess by allowing withdraw situations
to move not-in-flight buffer_heads to the ail2 list, where they will
be dealt with later.

Signed-off-by: Bob Peterson <rpeterso at redhat.com>
---
 fs/gfs2/log.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/fs/gfs2/log.c b/fs/gfs2/log.c
index 38a03c2203de..5dc889dae01f 100644
--- a/fs/gfs2/log.c
+++ b/fs/gfs2/log.c
@@ -111,11 +111,17 @@ __acquires(&sdp->sd_ail_lock)
 					      &sdp->sd_flags)) {
 				gfs2_io_error_bh(sdp, bh);
 				set_bit(SDF_WITHDRAWING, &sdp->sd_flags);
+			} else {
+				list_move(&bd->bd_ail_st_list,
+					  &tr->tr_ail2_list);
+				continue;
 			}
-			list_move(&bd->bd_ail_st_list, &tr->tr_ail2_list);
-			continue;
 		}
 
+		if (gfs2_withdrawn(sdp)) {
+			gfs2_remove_from_ail(bd);
+			continue;
+		}
 		if (!buffer_dirty(bh))
 			continue;
 		if (gl == bd->bd_gl)
@@ -861,6 +867,8 @@ void gfs2_log_flush(struct gfs2_sbd *sdp, struct gfs2_glock *gl, u32 flags)
 				if (gfs2_ail1_empty(sdp))
 					break;
 			}
+			if (gfs2_withdrawn(sdp))
+				goto out;
 			atomic_dec(&sdp->sd_log_blks_free); /* Adjust for unreserved buffer */
 			trace_gfs2_log_blocks(sdp, -1);
 			log_write_header(sdp, flags);
@@ -873,6 +881,7 @@ void gfs2_log_flush(struct gfs2_sbd *sdp, struct gfs2_glock *gl, u32 flags)
 			atomic_set(&sdp->sd_freeze_state, SFS_FROZEN);
 	}
 
+out:
 	trace_gfs2_log_flush(sdp, 0, flags);
 	up_write(&sdp->sd_log_flush_lock);
 
-- 
2.23.0