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authorPavan Sondur <pavan@gluster.com>2010-10-21 06:56:06 +0000
committerVijay Bellur <vijay@dev.gluster.com>2010-10-21 10:00:39 -0700
commit5cbc81a8d32434ff0c3e104ec802bcdc8c582f20 (patch)
treeda463650cb6bf10ff711b138dc373005a0b0f90d
parentef4005be3ac7f0f266f139c5b3d66538e35b924c (diff)
cluster/afr: Do a broadcast unlock in replicate to eliminate deadlock during upgrade/downgrade.v3.0.6rc2v3.0.6
Signed-off-by: Pavan Vilas Sondur <pavan@gluster.com> Signed-off-by: Vijay Bellur <vijay@dev.gluster.com> BUG: 1017 (Locking deadlock when upgrading lock) URL: http://bugs.gluster.com/cgi-bin/bugzilla3/show_bug.cgi?id=1017
-rw-r--r--xlators/cluster/afr/src/afr.c109
-rw-r--r--xlators/features/locks/src/common.c20
2 files changed, 118 insertions, 11 deletions
diff --git a/xlators/cluster/afr/src/afr.c b/xlators/cluster/afr/src/afr.c
index 3cdee3b..9df5d5c 100644
--- a/xlators/cluster/afr/src/afr.c
+++ b/xlators/cluster/afr/src/afr.c
@@ -2380,6 +2380,96 @@ afr_lk_cbk (call_frame_t *frame, void *cookie, xlator_t *this,
return 0;
}
+static int
+is_blocking_cmd (int32_t cmd)
+{
+ return (cmd == F_SETLKW);
+}
+
+static int32_t
+afr_do_real_lk (call_frame_t *frame, xlator_t *this)
+{
+ afr_private_t *priv = NULL;
+ afr_local_t *local = NULL;
+ int i = 0;
+
+ priv = this->private;
+ local = frame->local;
+
+ STACK_WIND_COOKIE (frame, afr_lk_cbk, (void *) (long) 0,
+ priv->children[i],
+ priv->children[i]->fops->lk,
+ local->fd, F_SETLKW,
+ &local->cont.lk.user_flock);
+
+ return 0;
+}
+
+int32_t
+afr_lk_unlock_broadcast_cbk (call_frame_t *frame, void *cookie, xlator_t *this,
+ int32_t op_ret, int32_t op_errno, struct flock *lock)
+{
+ afr_local_t *local = NULL;
+ int call_count = -1;
+
+ local = frame->local;
+ call_count = afr_frame_return (frame);
+
+ if (call_count == 0) {
+ gf_log (this->name, GF_LOG_TRACE,
+ "Got last unlock broadcast reply");
+
+ afr_do_real_lk (frame, this);
+ }
+
+ return 0;
+
+}
+
+static int
+afr_lk_unlock_broadcast (call_frame_t *frame, xlator_t *this,
+ struct flock *flock)
+{
+ afr_private_t *priv = NULL;
+ afr_local_t *local = NULL;
+ struct flock unlock = {0,};
+ int32_t call_count = 0;
+ int ret = 0;
+ int i = 0;
+
+ priv = this->private;
+ local = frame->local;
+
+ unlock.l_type = F_UNLCK;
+ unlock.l_whence = flock->l_whence;
+ unlock.l_start = flock->l_start;
+ unlock.l_len = flock->l_len;
+ unlock.l_pid = flock->l_pid;
+
+ call_count = afr_up_children_count (priv->child_count,
+ local->child_up);
+ if (call_count == 0) {
+ ret = -1;
+ goto out;
+ }
+
+ local->call_count = call_count;
+
+ for (i = 0; i < priv->child_count; i++) {
+ if (local->child_up[i]) {
+ STACK_WIND_COOKIE (frame, afr_lk_unlock_broadcast_cbk,
+ (void *) (long) 0,
+ priv->children[i],
+ priv->children[i]->fops->lk,
+ local->fd, F_SETLK, &unlock);
+ if (!--call_count)
+ break;
+ }
+ }
+
+out:
+ return ret;
+}
int
afr_lk (call_frame_t *frame, xlator_t *this,
@@ -2389,7 +2479,8 @@ afr_lk (call_frame_t *frame, xlator_t *this,
afr_private_t *priv = NULL;
afr_local_t *local = NULL;
- int i = 0;
+ int i = 0;
+ int ret = 0;
int32_t op_ret = -1;
int32_t op_errno = 0;
@@ -2419,6 +2510,22 @@ afr_lk (call_frame_t *frame, xlator_t *this,
local->cont.lk.user_flock = *flock;
local->cont.lk.ret_flock = *flock;
+ /* Send an unlock broadcast in the case of a blocking lock call
+ to prevent deadlock due to blocking lock upgrades / downgrades
+ */
+ if (is_blocking_cmd (cmd)) {
+ ret = afr_lk_unlock_broadcast (frame, this, flock);
+ if (ret) {
+ gf_log (this->name, GF_LOG_DEBUG,
+ "Could not send unlock broadcast");
+ } else {
+ op_ret = 0;
+ gf_log (this->name, GF_LOG_DEBUG,
+ "Sent unlock broadcast");
+ goto out;
+ }
+ }
+
STACK_WIND_COOKIE (frame, afr_lk_cbk, (void *) (long) 0,
priv->children[i],
priv->children[i]->fops->lk,
diff --git a/xlators/features/locks/src/common.c b/xlators/features/locks/src/common.c
index 483d7bf..9b712bb 100644
--- a/xlators/features/locks/src/common.c
+++ b/xlators/features/locks/src/common.c
@@ -923,17 +923,17 @@ pl_setlk (xlator_t *this, pl_inode_t *pl_inode, posix_lock_t *lock,
pthread_mutex_lock (&pl_inode->mutex);
{
- /* Send unlock before the actual lock to
- prevent lock upgrade / downgrade
- problems
+ /* Send unlock before the actual blocking lock
+ to support lock upgrades / downgrades.
*/
-
- ret = pl_send_prelock_unlock (this, pl_inode,
- lock);
- if (ret)
- gf_log (this->name, GF_LOG_DEBUG,
- "Could not send pre-lock "
- "unlock");
+ if (can_block) {
+ ret = pl_send_prelock_unlock (this, pl_inode,
+ lock);
+ if (ret)
+ gf_log (this->name, GF_LOG_DEBUG,
+ "Could not send pre-lock "
+ "unlock");
+ }
if (__is_lock_grantable (pl_inode, lock)) {
gf_log (this->name, GF_LOG_TRACE,