From 547bd2260fba782cb0a7a54589f9b6f75226776a Mon Sep 17 00:00:00 2001 From: Pranith Kumar K Date: Mon, 5 Dec 2016 13:20:51 +0530 Subject: [PATCH 232/235] 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: 1398188 Change-Id: Iae73b761f8247af1bb46f2ab82d5c7f7e86b8c17 Signed-off-by: Pranith Kumar K Reviewed-on: https://code.engineering.redhat.com/gerrit/92520 --- xlators/cluster/afr/src/afr-common.c | 48 +++++++-------------------- xlators/cluster/afr/src/afr-self-heal-entry.c | 34 +------------------ 2 files changed, 13 insertions(+), 69 deletions(-) diff --git a/xlators/cluster/afr/src/afr-common.c b/xlators/cluster/afr/src/afr-common.c index 55f10e7..b825b19 100644 --- a/xlators/cluster/afr/src/afr-common.c +++ b/xlators/cluster/afr/src/afr-common.c @@ -5218,7 +5218,6 @@ 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; @@ -5227,12 +5226,8 @@ 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); @@ -5253,42 +5248,23 @@ 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); diff --git a/xlators/cluster/afr/src/afr-self-heal-entry.c b/xlators/cluster/afr/src/afr-self-heal-entry.c index 6b5340a..2efeedf 100644 --- a/xlators/cluster/afr/src/afr-self-heal-entry.c +++ b/xlators/cluster/afr/src/afr-self-heal-entry.c @@ -21,11 +21,6 @@ * this name can ever come, entry-lock with this name is going to prevent * self-heals from older versions while the granular entry-self-heal is going * on in newer version.*/ -#define LONG_FILENAME "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"\ - "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"\ - "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"\ - "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"\ - "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa" static int afr_selfheal_entry_delete (xlator_t *this, inode_t *dir, const char *name, @@ -1051,21 +1046,16 @@ afr_selfheal_entry (call_frame_t *frame, xlator_t *this, inode_t *inode) { afr_private_t *priv = NULL; unsigned char *locked_on = NULL; - unsigned char *long_name_locked = NULL; fd_t *fd = NULL; int ret = 0; - gf_boolean_t granular_locks = _gf_false; priv = this->private; - if (strcmp ("granular", priv->locking_scheme) == 0) - granular_locks = _gf_true; fd = afr_selfheal_data_opendir (this, inode); if (!fd) return -EIO; locked_on = alloca0 (priv->child_count); - long_name_locked = alloca0 (priv->child_count); ret = afr_selfheal_tie_breaker_entrylk (frame, this, inode, priv->sh_domain, NULL, @@ -1085,29 +1075,7 @@ afr_selfheal_entry (call_frame_t *frame, xlator_t *this, inode_t *inode) goto unlock; } - if (!granular_locks) { - ret = afr_selfheal_tryentrylk (frame, this, inode, - this->name, LONG_FILENAME, - long_name_locked); - } - { - if (!granular_locks && ret < 1) { - gf_msg_debug (this->name, 0, "%s: Skipping" - " entry self-heal as only %d " - "sub-volumes could be " - "locked in special-filename " - "domain", - uuid_utoa (fd->inode->gfid), - ret); - ret = -ENOTCONN; - goto unlock; - } - ret = __afr_selfheal_entry (frame, this, fd, locked_on); - } - if (!granular_locks) - afr_selfheal_unentrylk (frame, this, inode, this->name, - LONG_FILENAME, long_name_locked, - NULL); + ret = __afr_selfheal_entry (frame, this, fd, locked_on); } unlock: afr_selfheal_unentrylk (frame, this, inode, priv->sh_domain, NULL, -- 2.9.3