From 042d4aaa55706332d5390d8ee01c6a747c6c3118 Mon Sep 17 00:00:00 2001 From: Pranith Kumar K Date: Mon, 5 Dec 2016 13:20:51 +0530 Subject: cluster/afr: Remove backward compatibility for locks with v1 When we have cascading locks with same lk-owner there is a possibility for a deadlock to happen. One example is as follows: self-heal takes a lock in data-domain for big name with 256 chars of "aaaa...a" and starts heal in a 3-way replication when brick-0 is offline and healing from brick-1 to brick-2 is in progress. So this lock is active on brick-1 and brick-2. Now brick-0 comes online and an operation wants to take full lock and the lock is granted at brick-0 and it is waiting for lock on brick-1. As part of entry healing it takes full locks on all the available bricks and then proceeds with healing the entry. Now this lock will start waiting on brick-0 because some other operation already has a granted lock on it. This leads to a deadlock. Operation is waiting for unlock on "aaaa..." by heal where as heal is waiting for the operation to unlock on brick-0. Initially I thought this is happening because healing is trying to take a lock on all the available bricks instead of just the bricks that are participating in heal. But later realized that same kind of deadlock can happen if a brick goes down after the heal starts but comes back before it completes. So the essential problem is the cascading locks with same lk-owner which were added for backward compatibility with afr-v1 which can be safely removed now that versions with afr-v1 are already EOL. This patch removes the compatibility with v1 which requires cascading locks with same lk-owner. In the next version we can make locking-scheme option a dummy and switch completely to v2. >BUG: 1401404 >Change-Id: Ic9afab8260f5ff4dff5329eb0429811bcb879079 >Signed-off-by: Pranith Kumar K >Reviewed-on: http://review.gluster.org/16024 >Smoke: Gluster Build System >Reviewed-by: Ravishankar N >NetBSD-regression: NetBSD Build System >CentOS-regression: Gluster Build System BUG: 1413062 Change-Id: I4f5d485d9e0646ad3dc384e5ec36682b0933c9d3 Signed-off-by: Pranith Kumar K Reviewed-on: http://review.gluster.org/16413 Smoke: Gluster Build System CentOS-regression: Gluster Build System NetBSD-regression: NetBSD Build System --- xlators/cluster/afr/src/afr-common.c | 48 +++++++++--------------------------- 1 file changed, 12 insertions(+), 36 deletions(-) (limited to 'xlators/cluster/afr/src/afr-common.c') diff --git a/xlators/cluster/afr/src/afr-common.c b/xlators/cluster/afr/src/afr-common.c index 86892ea6f06..6fbfda3934a 100644 --- a/xlators/cluster/afr/src/afr-common.c +++ b/xlators/cluster/afr/src/afr-common.c @@ -5312,7 +5312,6 @@ afr_selfheal_locked_data_inspect (call_frame_t *frame, xlator_t *this, gf_boolean_t *pflag) { int ret = -1; - unsigned char *locked_on = NULL; unsigned char *data_lock = NULL; unsigned char *sources = NULL; unsigned char *sinks = NULL; @@ -5321,12 +5320,8 @@ afr_selfheal_locked_data_inspect (call_frame_t *frame, xlator_t *this, afr_private_t *priv = NULL; fd_t *fd = NULL; struct afr_reply *locked_replies = NULL; - gf_boolean_t granular_locks = _gf_false; priv = this->private; - if (strcmp ("granular", priv->locking_scheme) == 0) - granular_locks = _gf_true; - locked_on = alloca0 (priv->child_count); data_lock = alloca0 (priv->child_count); sources = alloca0 (priv->child_count); sinks = alloca0 (priv->child_count); @@ -5347,42 +5342,23 @@ afr_selfheal_locked_data_inspect (call_frame_t *frame, xlator_t *this, locked_replies = alloca0 (sizeof (*locked_replies) * priv->child_count); - if (!granular_locks) { - ret = afr_selfheal_tryinodelk (frame, this, inode, - priv->sh_domain, 0, 0, locked_on); - } + ret = afr_selfheal_inodelk (frame, this, inode, this->name, + 0, 0, data_lock); { - if (!granular_locks && (ret == 0)) { + if (ret == 0) { ret = -afr_final_errno (frame->local, priv); if (ret == 0) - ret = -ENOTCONN;/* all invalid responses */ + ret = -ENOTCONN; /* all invalid responses */ goto out; } - ret = afr_selfheal_inodelk (frame, this, inode, this->name, - 0, 0, data_lock); - { - if (ret == 0) { - ret = -afr_final_errno (frame->local, priv); - if (ret == 0) - ret = -ENOTCONN; - /* all invalid responses */ - goto unlock; - } - ret = __afr_selfheal_data_prepare (frame, this, inode, - data_lock, sources, - sinks, healed_sinks, - undid_pending, - locked_replies, - pflag); - *dsh = afr_decide_heal_info (priv, sources, ret); - } - afr_selfheal_uninodelk (frame, this, inode, this->name, 0, 0, - data_lock); - } -unlock: - if (!granular_locks) - afr_selfheal_uninodelk (frame, this, inode, priv->sh_domain, 0, - 0, locked_on); + ret = __afr_selfheal_data_prepare (frame, this, inode, + data_lock, sources, sinks, + healed_sinks, undid_pending, + locked_replies, pflag); + *dsh = afr_decide_heal_info (priv, sources, ret); + } + afr_selfheal_uninodelk (frame, this, inode, this->name, 0, 0, + data_lock); out: if (locked_replies) afr_replies_wipe (locked_replies, priv->child_count); -- cgit