Adding upstream version 1:10.5.12.upstream/1%10.5.12upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 776 insertions, 0 deletions

diff --git a/storage/maria/lockman.c b/storage/maria/lockman.c
new file mode 100644
index 00000000..4cf6a46e
--- /dev/null
+++ b/storage/maria/lockman.c
@@ -0,0 +1,776 @@
+/* QQ: TODO - allocate everything from dynarrays !!! (benchmark) */
+/* QQ: TODO instant duration locks */
+/* QQ: #warning automatically place S instead of LS if possible */
+
+/* Copyright (C) 2006 MySQL AB
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; version 2 of the License.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1335 USA */
+
+/*
+  Generic Lock Manager
+
+  Lock manager handles locks on "resources", a resource must be uniquely
+  identified by a 64-bit number. Lock manager itself does not imply
+  anything about the nature of a resource - it can be a row, a table, a
+  database, or just anything.
+
+  Locks belong to "lock owners". A Lock owner is uniquely identified by a
+  16-bit number. A function loid2lo must be provided by the application
+  that takes such a number as an argument and returns a LOCK_OWNER
+  structure.
+
+  Lock levels are completely defined by three tables. Lock compatibility
+  matrix specifies which locks can be held at the same time on a resource.
+  Lock combining matrix specifies what lock level has the same behaviour as
+  a pair of two locks of given levels. getlock_result matrix simplifies
+  intention locking and lock escalation for an application, basically it
+  defines which locks are intention locks and which locks are "loose"
+  locks.  It is only used to provide better diagnostics for the
+  application, lock manager itself does not differentiate between normal,
+  intention, and loose locks.
+
+  Internally lock manager is based on a lock-free hash, see lf_hash.c for
+  details.  All locks are stored in a hash, with a resource id as a search
+  key, so all locks for the same resource will be considered collisions and
+  will be put in a one (lock-free) linked list.  The main lock-handling
+  logic is in the inner loop that searches for a lock in such a linked
+  list - lockfind().
+
+  This works as follows. Locks generally are added to the end of the list
+  (with one exception, see below). When scanning the list it is always
+  possible to determine what locks are granted (active) and what locks are
+  waiting - first lock is obviously active, the second is active if it's
+  compatible with the first, and so on, a lock is active if it's compatible
+  with all previous locks and all locks before it are also active.
+  To calculate the "compatible with all previous locks" all locks are
+  accumulated in prev_lock variable using lock_combining_matrix.
+
+  Lock upgrades: when a thread that has a lock on a given resource,
+  requests a new lock on the same resource and the old lock is not enough
+  to satisfy new lock requirements (which is defined by
+  lock_combining_matrix[old_lock][new_lock] != old_lock), a new lock is
+  placed in the list. Depending on other locks it is immediately active or
+  it will wait for other locks. Here's an exception to "locks are added
+  to the end" rule - upgraded locks are added after the last active lock
+  but before all waiting locks. Old lock (the one we upgraded from) is
+  not removed from the list, indeed it may be needed if the new lock was
+  in a savepoint that gets rolled back. So old lock is marked as "ignored"
+  (IGNORE_ME flag). New lock gets an UPGRADED flag.
+
+  Loose locks add an important exception to the above. Loose locks do not
+  always commute with other locks. In the list IX-LS both locks are active,
+  while in the LS-IX list only the first lock is active. This creates a
+  problem in lock upgrades. If the list was IX-LS and the owner of the
+  first lock wants to place LS lock (which can be immediately granted), the
+  IX lock is upgraded to LSIX and the list becomes IX-LS-LSIX, which,
+  according to the lock compatibility matrix means that the last lock is
+  waiting - of course it all happened because IX and LS were swapped and
+  they don't commute. To work around this there's ACTIVE flag which is set
+  in every lock that never waited (was placed active), and this flag
+  overrides "compatible with all previous locks" rule.
+
+  When a lock is placed to the end of the list it's either compatible with
+  all locks and all locks are active - new lock becomes active at once, or
+  it conflicts with some of the locks, in this case in the 'blocker'
+  variable a conflicting lock is returned and the calling thread waits on a
+  pthread condition in the LOCK_OWNER structure of the owner of the
+  conflicting lock. Or a new lock is compatible with all locks, but some
+  existing locks are not compatible with each other (example: request IS,
+  when the list is S-IX) - that is not all locks are active. In this case a
+  first waiting lock is returned in the 'blocker' variable, lockman_getlock()
+  notices that a "blocker" does not conflict with the requested lock, and
+  "dereferences" it, to find the lock that it's waiting on.  The calling
+  thread than begins to wait on the same lock.
+
+  To better support table-row relations where one needs to lock the table
+  with an intention lock before locking the row, extended diagnostics is
+  provided.  When an intention lock (presumably on a table) is granted,
+  lockman_getlock() returns one of GOT_THE_LOCK (no need to lock the row,
+  perhaps the thread already has a normal lock on this table),
+  GOT_THE_LOCK_NEED_TO_LOCK_A_SUBRESOURCE (need to lock the row, as usual),
+  GOT_THE_LOCK_NEED_TO_INSTANT_LOCK_A_SUBRESOURCE (only need to check
+  whether it's possible to lock the row, but no need to lock it - perhaps
+  the thread has a loose lock on this table). This is defined by
+  getlock_result[] table.
+*/
+
+#include <my_global.h>
+#include <my_sys.h>
+#include <my_bit.h>
+#include <lf.h>
+#include "my_cpu.h"
+#include "lockman.h"
+
+/*
+  Lock compatibility matrix.
+
+  It's asymmetric. Read it as "Somebody has the lock <value in the row
+  label>, can I set the lock <value in the column label> ?"
+
+  ') Though you can take LS lock while somebody has S lock, it makes no
+  sense - it's simpler to take S lock too.
+
+  1  - compatible
+  0  - incompatible
+  -1 - "impossible", so that we can assert the impossibility.
+*/
+static int lock_compatibility_matrix[10][10]=
+{ /* N    S   X  IS  IX  SIX LS  LX  SLX LSIX          */
+  {  -1,  1,  1,  1,  1,  1,  1,  1,  1,  1 }, /* N    */
+  {  -1,  1,  0,  1,  0,  0,  1,  0,  0,  0 }, /* S    */
+  {  -1,  0,  0,  0,  0,  0,  0,  0,  0,  0 }, /* X    */
+  {  -1,  1,  0,  1,  1,  1,  1,  1,  1,  1 }, /* IS   */
+  {  -1,  0,  0,  1,  1,  0,  1,  1,  0,  1 }, /* IX   */
+  {  -1,  0,  0,  1,  0,  0,  1,  0,  0,  0 }, /* SIX  */
+  {  -1,  1,  0,  1,  0,  0,  1,  0,  0,  0 }, /* LS   */
+  {  -1,  0,  0,  0,  0,  0,  0,  0,  0,  0 }, /* LX   */
+  {  -1,  0,  0,  0,  0,  0,  0,  0,  0,  0 }, /* SLX  */
+  {  -1,  0,  0,  1,  0,  0,  1,  0,  0,  0 }  /* LSIX */
+};
+
+/*
+  Lock combining matrix.
+
+  It's symmetric. Read it as "what lock level L is identical to the
+  set of two locks A and B"
+
+  One should never get N from it, we assert the impossibility
+*/
+static enum lockman_lock_type lock_combining_matrix[10][10]=
+{/*    N    S   X    IS    IX  SIX    LS    LX   SLX   LSIX         */
+  {    N,   S,  X,   IS,   IX, SIX,    S,  SLX, SLX,  SIX}, /* N    */
+  {    S,   S,  X,    S,  SIX, SIX,    S,  SLX, SLX,  SIX}, /* S    */
+  {    X,   X,  X,    X,    X,   X,    X,    X,   X,    X}, /* X    */
+  {   IS,   S,  X,   IS,   IX, SIX,   LS,   LX, SLX, LSIX}, /* IS   */
+  {   IX, SIX,  X,   IX,   IX, SIX, LSIX,   LX, SLX, LSIX}, /* IX   */
+  {  SIX, SIX,  X,  SIX,  SIX, SIX,  SIX,  SLX, SLX,  SIX}, /* SIX  */
+  {   LS,   S,  X,   LS, LSIX, SIX,   LS,   LX, SLX, LSIX}, /* LS   */
+  {   LX, SLX,  X,   LX,   LX, SLX,   LX,   LX, SLX,   LX}, /* LX   */
+  {  SLX, SLX,  X,  SLX,  SLX, SLX,  SLX,  SLX, SLX,  SLX}, /* SLX  */
+  { LSIX, SIX,  X, LSIX, LSIX, SIX, LSIX,   LX, SLX, LSIX}  /* LSIX */
+};
+
+#define REPEAT_ONCE_MORE                0
+#define OK_TO_PLACE_THE_LOCK            1
+#define OK_TO_PLACE_THE_REQUEST         2
+#define ALREADY_HAVE_THE_LOCK           4
+#define ALREADY_HAVE_THE_REQUEST        8
+#define PLACE_NEW_DISABLE_OLD          16
+#define REQUEST_NEW_DISABLE_OLD        32
+#define RESOURCE_WAS_UNLOCKED          64
+
+#define NEED_TO_WAIT (OK_TO_PLACE_THE_REQUEST | ALREADY_HAVE_THE_REQUEST |\
+                      REQUEST_NEW_DISABLE_OLD)
+#define ALREADY_HAVE (ALREADY_HAVE_THE_LOCK   | ALREADY_HAVE_THE_REQUEST)
+#define LOCK_UPGRADE (PLACE_NEW_DISABLE_OLD   | REQUEST_NEW_DISABLE_OLD)
+
+
+/*
+  the return codes for lockman_getlock
+
+  It's asymmetric. Read it as "I have the lock <value in the row label>,
+  what value should be returned for <value in the column label> ?"
+
+  0 means impossible combination (assert!)
+
+  Defines below help to preserve the table structure.
+  I/L/A values are self explanatory
+  x means the combination is possible (assert should not crash)
+    but it cannot happen in row locks, only in table locks (S,X),
+    or lock escalations (LS,LX)
+*/
+#define I GOT_THE_LOCK_NEED_TO_LOCK_A_SUBRESOURCE
+#define L GOT_THE_LOCK_NEED_TO_INSTANT_LOCK_A_SUBRESOURCE
+#define A GOT_THE_LOCK
+#define x GOT_THE_LOCK
+static enum lockman_getlock_result getlock_result[10][10]=
+{/*    N    S   X    IS    IX  SIX    LS    LX   SLX   LSIX         */
+  {    0,   0,  0,    0,    0,   0,    0,    0,   0,    0}, /* N    */
+  {    0,   x,  0,    A,    0,   0,    x,    0,   0,    0}, /* S    */
+  {    0,   x,  x,    A,    A,   0,    x,    x,   0,    0}, /* X    */
+  {    0,   0,  0,    I,    0,   0,    0,    0,   0,    0}, /* IS   */
+  {    0,   0,  0,    I,    I,   0,    0,    0,   0,    0}, /* IX   */
+  {    0,   x,  0,    A,    I,   0,    x,    0,   0,    0}, /* SIX  */
+  {    0,   0,  0,    L,    0,   0,    x,    0,   0,    0}, /* LS   */
+  {    0,   0,  0,    L,    L,   0,    x,    x,   0,    0}, /* LX   */
+  {    0,   x,  0,    A,    L,   0,    x,    x,   0,    0}, /* SLX  */
+  {    0,   0,  0,    L,    I,   0,    x,    0,   0,    0}  /* LSIX */
+};
+#undef I
+#undef L
+#undef A
+#undef x
+
+typedef struct lockman_lock {
+  uint64 resource;
+  struct lockman_lock  *lonext;
+  intptr volatile link;
+  uint32 hashnr;
+  /* QQ: TODO - remove hashnr from LOCK */
+  uint16 loid;
+  uchar lock;              /* sizeof(uchar) <= sizeof(enum) */
+  uchar flags;
+} LOCK;
+
+#define IGNORE_ME               1
+#define UPGRADED                2
+#define ACTIVE                  4
+
+typedef struct {
+  intptr volatile *prev;
+  LOCK *curr, *next;
+  LOCK *blocker, *upgrade_from;
+} CURSOR;
+
+#define PTR(V)      (LOCK *)((V) & (~(intptr)1))
+#define DELETED(V)  ((V) & 1)
+
+/*
+  NOTE
+    cursor is positioned in either case
+    pins[0..3] are used, they are NOT removed on return
+*/
+static int lockfind(LOCK * volatile *head, LOCK *node,
+                    CURSOR *cursor, LF_PINS *pins)
+{
+  uint32        hashnr, cur_hashnr;
+  uint64        resource, cur_resource;
+  intptr        cur_link;
+  my_bool       cur_active, compatible, upgrading, prev_active;
+  enum lockman_lock_type lock, prev_lock, cur_lock;
+  uint16        loid, cur_loid;
+  int           cur_flags, flags;
+
+  hashnr= node->hashnr;
+  resource= node->resource;
+  lock= node->lock;
+  loid= node->loid;
+  flags= node->flags;
+
+retry:
+  cursor->prev= (intptr *)head;
+  prev_lock= N;
+  cur_active= TRUE;
+  compatible= TRUE;
+  upgrading= FALSE;
+  cursor->blocker= cursor->upgrade_from= 0;
+  lf_unpin(pins, 3);
+  do {
+    cursor->curr= PTR(*cursor->prev);
+    lf_pin(pins, 1, cursor->curr);
+  } while(*cursor->prev != (intptr)cursor->curr && LF_BACKOFF());
+  for (;;)
+  {
+    if (!cursor->curr)
+      break;
+    do {
+      cur_link= cursor->curr->link;
+      cursor->next= PTR(cur_link);
+      lf_pin(pins, 0, cursor->next);
+    } while (cur_link != cursor->curr->link && LF_BACKOFF());
+    cur_hashnr= cursor->curr->hashnr;
+    cur_resource= cursor->curr->resource;
+    cur_lock= cursor->curr->lock;
+    cur_loid= cursor->curr->loid;
+    cur_flags= cursor->curr->flags;
+    if (*cursor->prev != (intptr)cursor->curr)
+    {
+      (void)LF_BACKOFF();
+      goto retry;
+    }
+    if (!DELETED(cur_link))
+    {
+      if (cur_hashnr > hashnr ||
+          (cur_hashnr == hashnr && cur_resource >= resource))
+      {
+        if (cur_hashnr > hashnr || cur_resource > resource)
+          break;
+        /* ok, we have a lock for this resource */
+        DBUG_ASSERT(lock_compatibility_matrix[prev_lock][cur_lock] >= 0);
+        DBUG_ASSERT(lock_compatibility_matrix[cur_lock][lock] >= 0);
+        if ((cur_flags & IGNORE_ME) && ! (flags & IGNORE_ME))
+        {
+          DBUG_ASSERT(cur_active);
+          if (cur_loid == loid)
+            cursor->upgrade_from= cursor->curr;
+        }
+        else
+        {
+          prev_active= cur_active;
+          if (cur_flags & ACTIVE)
+            DBUG_ASSERT(prev_active == TRUE);
+          else
+            cur_active&= lock_compatibility_matrix[prev_lock][cur_lock];
+          if (upgrading && !cur_active /*&& !(cur_flags & UPGRADED)*/)
+            break;
+          if (prev_active && !cur_active)
+          {
+            cursor->blocker= cursor->curr;
+            lf_pin(pins, 3, cursor->curr);
+          }
+          if (cur_loid == loid)
+          {
+            /* we already have a lock on this resource */
+            DBUG_ASSERT(lock_combining_matrix[cur_lock][lock] != N);
+            DBUG_ASSERT(!upgrading || (flags & IGNORE_ME));
+            if (lock_combining_matrix[cur_lock][lock] == cur_lock)
+            {
+              /* new lock is compatible */
+              if (cur_active)
+              {
+                cursor->blocker= cursor->curr;  /* loose-locks! */
+                lf_unpin(pins, 3);             /* loose-locks! */
+                return ALREADY_HAVE_THE_LOCK;
+              }
+              else
+                return ALREADY_HAVE_THE_REQUEST;
+            }
+            /* not compatible, upgrading */
+            upgrading= TRUE;
+            cursor->upgrade_from= cursor->curr;
+          }
+          else
+          {
+            if (!lock_compatibility_matrix[cur_lock][lock])
+            {
+              compatible= FALSE;
+              cursor->blocker= cursor->curr;
+              lf_pin(pins, 3, cursor->curr);
+            }
+          }
+          prev_lock= lock_combining_matrix[prev_lock][cur_lock];
+          DBUG_ASSERT(prev_lock != N);
+        }
+      }
+      cursor->prev= &(cursor->curr->link);
+      lf_pin(pins, 2, cursor->curr);
+    }
+    else
+    {
+      if (my_atomic_casptr((void **)cursor->prev,
+                           (void **)(char*) &cursor->curr, cursor->next))
+        lf_alloc_free(pins, cursor->curr);
+      else
+      {
+        (void)LF_BACKOFF();
+        goto retry;
+      }
+    }
+    cursor->curr= cursor->next;
+    lf_pin(pins, 1, cursor->curr);
+  }
+  /*
+    either the end of lock list - no more locks for this resource,
+    or upgrading and the end of active lock list
+  */
+  if (upgrading)
+  {
+    if (compatible /*&& prev_active*/)
+      return PLACE_NEW_DISABLE_OLD;
+    else
+      return REQUEST_NEW_DISABLE_OLD;
+  }
+  if (cur_active && compatible)
+  {
+    /*
+      either no locks for this resource or all are compatible.
+      ok to place the lock in any case.
+    */
+    return prev_lock == N ? RESOURCE_WAS_UNLOCKED
+                          : OK_TO_PLACE_THE_LOCK;
+  }
+  /* we have a lock conflict. ok to place a lock request. And wait */
+  return OK_TO_PLACE_THE_REQUEST;
+}
+
+/*
+  NOTE
+    it uses pins[0..3], on return pins 0..2 are removed, pin 3 (blocker) stays
+*/
+static int lockinsert(LOCK * volatile *head, LOCK *node, LF_PINS *pins,
+                      LOCK **blocker)
+{
+  CURSOR         cursor;
+  int            res;
+
+  do
+  {
+    res= lockfind(head, node, &cursor, pins);
+    DBUG_ASSERT(res != ALREADY_HAVE_THE_REQUEST);
+    if (!(res & ALREADY_HAVE))
+    {
+      if (res & LOCK_UPGRADE)
+      {
+        node->flags|= UPGRADED;
+        node->lock= lock_combining_matrix[cursor.upgrade_from->lock][node->lock];
+      }
+      if (!(res & NEED_TO_WAIT))
+        node->flags|= ACTIVE;
+      node->link= (intptr)cursor.curr;
+      DBUG_ASSERT(node->link != (intptr)node);
+      DBUG_ASSERT(cursor.prev != &node->link);
+      if (!my_atomic_casptr((void **)cursor.prev,
+                            (void **)(char*) &cursor.curr, node))
+      {
+        res= REPEAT_ONCE_MORE;
+        node->flags&= ~ACTIVE;
+      }
+      if (res & LOCK_UPGRADE)
+        cursor.upgrade_from->flags|= IGNORE_ME;
+      /*
+        QQ: is this OK ? if a reader has already read upgrade_from,
+        it may find it conflicting with node :(
+        - see the last test from test_lockman_simple()
+      */
+    }
+
+  } while (res == REPEAT_ONCE_MORE);
+  lf_unpin(pins, 0);
+  lf_unpin(pins, 1);
+  lf_unpin(pins, 2);
+  /*
+    note that blocker is not necessarily pinned here (when it's == curr).
+    this is ok as in such a case it's either a dummy node for
+    initialize_bucket() and dummy nodes don't need pinning,
+    or it's a lock of the same transaction for lockman_getlock,
+    and it cannot be removed by another thread
+  */
+  *blocker= cursor.blocker;
+  return res;
+}
+
+/*
+  NOTE
+    it uses pins[0..3], on return pins 0..2 are removed, pin 3 (blocker) stays
+*/
+static int lockpeek(LOCK * volatile *head, LOCK *node, LF_PINS *pins,
+                    LOCK **blocker)
+{
+  CURSOR         cursor;
+  int            res;
+
+  res= lockfind(head, node, &cursor, pins);
+
+  lf_unpin(pins, 0);
+  lf_unpin(pins, 1);
+  lf_unpin(pins, 2);
+  if (blocker)
+    *blocker= cursor.blocker;
+  return res;
+}
+
+/*
+  NOTE
+    it uses pins[0..3], on return all pins are removed.
+
+    One _must_ have the lock (or request) to call this
+*/
+static int lockdelete(LOCK * volatile *head, LOCK *node, LF_PINS *pins)
+{
+  CURSOR cursor;
+  int res;
+
+  do
+  {
+    res= lockfind(head, node, &cursor, pins);
+    DBUG_ASSERT(res & ALREADY_HAVE);
+
+    if (cursor.upgrade_from)
+      cursor.upgrade_from->flags&= ~IGNORE_ME;
+
+    /*
+      XXX this does not work with savepoints, as old lock is left ignored.
+      It cannot be unignored, as would basically mean moving the lock back
+      in the lock chain (from upgraded). And the latter is not allowed -
+      because it breaks list scanning. So old ignored lock must be deleted,
+      new - same - lock must be installed right after the lock we're deleting,
+      then we can delete. Good news is - this is only required when rolling
+      back a savepoint.
+    */
+    if (my_atomic_casptr((void **)(char*)&(cursor.curr->link),
+                         (void **)(char*)&cursor.next, 1+(char *)cursor.next))
+    {
+      if (my_atomic_casptr((void **)cursor.prev,
+                           (void **)(char*)&cursor.curr, cursor.next))
+        lf_alloc_free(pins, cursor.curr);
+      else
+        lockfind(head, node, &cursor, pins);
+    }
+    else
+    {
+      res= REPEAT_ONCE_MORE;
+      if (cursor.upgrade_from)
+        cursor.upgrade_from->flags|= IGNORE_ME;
+    }
+  } while (res == REPEAT_ONCE_MORE);
+  lf_unpin(pins, 0);
+  lf_unpin(pins, 1);
+  lf_unpin(pins, 2);
+  lf_unpin(pins, 3);
+  return res;
+}
+
+void lockman_init(LOCKMAN *lm, loid_to_lo_func *func, uint timeout)
+{
+  lf_alloc_init(&lm->alloc, sizeof(LOCK), offsetof(LOCK, lonext));
+  lf_dynarray_init(&lm->array, sizeof(LOCK **));
+  lm->size= 1;
+  lm->count= 0;
+  lm->loid_to_lo= func;
+  lm->lock_timeout= timeout;
+}
+
+void lockman_destroy(LOCKMAN *lm)
+{
+  LOCK *el= *(LOCK **)lf_dynarray_lvalue(&lm->array, 0);
+  while (el)
+  {
+    intptr next= el->link;
+    if (el->hashnr & 1)
+      lf_alloc_direct_free(&lm->alloc, el);
+    else
+      my_free((void *)el);
+    el= (LOCK *)next;
+  }
+  lf_alloc_destroy(&lm->alloc);
+  lf_dynarray_destroy(&lm->array);
+}
+
+/* TODO: optimize it */
+#define MAX_LOAD 1
+
+static void initialize_bucket(LOCKMAN *lm, LOCK * volatile *node,
+                              uint bucket, LF_PINS *pins)
+{
+  int res;
+  uint parent= my_clear_highest_bit(bucket);
+  LOCK *dummy= (LOCK *)my_malloc(PSI_INSTRUMENT_ME, sizeof(LOCK), MYF(MY_WME));
+  LOCK **tmp= 0, *cur;
+  LOCK * volatile *el= lf_dynarray_lvalue(&lm->array, parent);
+
+  if (*el == NULL && bucket)
+    initialize_bucket(lm, el, parent, pins);
+  dummy->hashnr= my_reverse_bits(bucket);
+  dummy->loid= 0;
+  dummy->lock= X; /* doesn't matter, in fact */
+  dummy->resource= 0;
+  dummy->flags= 0;
+  res= lockinsert(el, dummy, pins, &cur);
+  DBUG_ASSERT(res & (ALREADY_HAVE_THE_LOCK | RESOURCE_WAS_UNLOCKED));
+  if (res & ALREADY_HAVE_THE_LOCK)
+  {
+    my_free((void *)dummy);
+    dummy= cur;
+  }
+  my_atomic_casptr((void **)node, (void **)(char*) &tmp, dummy);
+}
+
+static inline uint calc_hash(uint64 resource)
+{
+  const uchar *pos= (uchar *)&resource;
+  ulong nr1= 1, nr2= 4, i;
+  for (i= 0; i < sizeof(resource) ; i++, pos++)
+  {
+    nr1^= (ulong) ((((uint) nr1 & 63)+nr2) * ((uint)*pos)) + (nr1 << 8);
+    nr2+= 3;
+  }
+  return nr1 & INT_MAX32;
+}
+
+/*
+  RETURN
+    see enum lockman_getlock_result
+  NOTE
+    uses pins[0..3], they're removed on return
+*/
+enum lockman_getlock_result lockman_getlock(LOCKMAN *lm, LOCK_OWNER *lo,
+                                            uint64 resource,
+                                            enum lockman_lock_type lock)
+{
+  int res;
+  uint csize, bucket, hashnr;
+  LOCK *node, * volatile *el, *blocker;
+  LF_PINS *pins= lo->pins;
+  enum lockman_lock_type old_lock;
+
+  DBUG_ASSERT(lo->loid);
+  node= (LOCK *)lf_alloc_new(pins);
+  node->flags= 0;
+  node->lock= lock;
+  node->loid= lo->loid;
+  node->resource= resource;
+  hashnr= calc_hash(resource);
+  bucket= hashnr % lm->size;
+  el= lf_dynarray_lvalue(&lm->array, bucket);
+  if (*el == NULL)
+    initialize_bucket(lm, el, bucket, pins);
+  node->hashnr= my_reverse_bits(hashnr) | 1;
+  res= lockinsert(el, node, pins, &blocker);
+  if (res & ALREADY_HAVE)
+  {
+    int r;
+    old_lock= blocker->lock;
+    lf_alloc_free(pins, node);
+    r= getlock_result[old_lock][lock];
+    DBUG_ASSERT(r);
+    return r;
+  }
+  /* a new value was added to the hash */
+  csize= lm->size;
+  if ((my_atomic_add32(&lm->count, 1)+1.0) / csize > MAX_LOAD)
+    my_atomic_cas32(&lm->size, (int*) &csize, csize*2);
+  node->lonext= lo->all_locks;
+  lo->all_locks= node;
+  for ( ; res & NEED_TO_WAIT; res= lockpeek(el, node, pins, &blocker))
+  {
+    LOCK_OWNER *wait_for_lo;
+    ulonglong deadline;
+    struct timespec timeout;
+
+    lf_assert_pin(pins, 3); /* blocker must be pinned here */
+    wait_for_lo= lm->loid_to_lo(blocker->loid);
+
+    /*
+      now, this is tricky. blocker is not necessarily a LOCK
+      we're waiting for. If it's compatible with what we want,
+      then we're waiting for a lock that blocker is waiting for
+      (see two places where blocker is set in lockfind)
+      In the latter case, let's "dereference" it
+    */
+    if (lock_compatibility_matrix[blocker->lock][lock])
+    {
+      blocker= wait_for_lo->all_locks;
+      lf_pin(pins, 3, blocker);
+      if (blocker != wait_for_lo->all_locks)
+        continue;
+      wait_for_lo= wait_for_lo->waiting_for;
+    }
+
+    /*
+      note that the blocker transaction may have ended by now,
+      its LOCK_OWNER and short id were reused, so 'wait_for_lo' may point
+      to an unrelated - albeit valid - LOCK_OWNER
+    */
+    if (!wait_for_lo)
+      continue;
+
+    lo->waiting_for= wait_for_lo;
+
+    /*
+      We lock a mutex - it may belong to a wrong LOCK_OWNER, but it must
+      belong to _some_ LOCK_OWNER. It means, we can never free() a LOCK_OWNER,
+      if there're other active LOCK_OWNERs.
+    */
+    /* QQ: race condition here */
+    pthread_mutex_lock(wait_for_lo->mutex);
+    if (DELETED(blocker->link))
+    {
+      /*
+        blocker transaction was ended, or a savepoint that owned
+        the lock was rolled back. Either way - the lock was removed
+      */
+      pthread_mutex_unlock(wait_for_lo->mutex);
+      continue;
+    }
+
+    /* yuck. waiting */
+    deadline= my_hrtime().val*1000 + lm->lock_timeout * 1000000;
+    set_timespec_time_nsec(timeout, deadline);
+    do
+    {
+      pthread_cond_timedwait(wait_for_lo->cond, wait_for_lo->mutex, &timeout);
+    } while (!DELETED(blocker->link) && my_hrtime().val < deadline/1000);
+    pthread_mutex_unlock(wait_for_lo->mutex);
+    if (!DELETED(blocker->link))
+    {
+      /*
+        timeout.
+        note that we _don't_ release the lock request here.
+        Instead we're relying on the caller to abort the transaction,
+        and release all locks at once - see lockman_release_locks()
+      */
+      lf_unpin(pins, 3);
+      return DIDNT_GET_THE_LOCK;
+    }
+  }
+  lo->waiting_for= 0;
+  lf_assert_unpin(pins, 3); /* unpin should not be needed */
+  return getlock_result[lock][lock];
+}
+
+/*
+  RETURN
+    0 - deleted
+    1 - didn't (not found)
+  NOTE
+    see lockdelete() for pin usage notes
+*/
+int lockman_release_locks(LOCKMAN *lm, LOCK_OWNER *lo)
+{
+  LOCK * volatile *el, *node, *next;
+  uint bucket;
+  LF_PINS *pins= lo->pins;
+
+  pthread_mutex_lock(lo->mutex);
+  for (node= lo->all_locks; node; node= next)
+  {
+    next= node->lonext;
+    bucket= calc_hash(node->resource) % lm->size;
+    el= lf_dynarray_lvalue(&lm->array, bucket);
+    if (*el == NULL)
+      initialize_bucket(lm, el, bucket, pins);
+    lockdelete(el, node, pins);
+    my_atomic_add32(&lm->count, -1);
+  }
+  lo->all_locks= 0;
+  /* now signal all waiters */
+  pthread_cond_broadcast(lo->cond);
+  pthread_mutex_unlock(lo->mutex);
+  return 0;
+}
+
+#ifdef MY_LF_EXTRA_DEBUG
+static const char *lock2str[]=
+{ "N", "S", "X", "IS", "IX", "SIX", "LS", "LX", "SLX", "LSIX" };
+/*
+  NOTE
+    the function below is NOT thread-safe !!!
+*/
+void print_lockhash(LOCKMAN *lm)
+{
+  LOCK *el= *(LOCK **)lf_dynarray_lvalue(&lm->array, 0);
+  printf("hash: size %u count %u\n", lm->size, lm->count);
+  while (el)
+  {
+    intptr next= el->link;
+    if (el->hashnr & 1)
+    {
+      printf("0x%08lx { resource %lu, loid %u, lock %s",
+             (long) el->hashnr, (ulong) el->resource, el->loid,
+             lock2str[el->lock]);
+      if (el->flags & IGNORE_ME) printf(" IGNORE_ME");
+      if (el->flags & UPGRADED) printf(" UPGRADED");
+      if (el->flags & ACTIVE) printf(" ACTIVE");
+      if (DELETED(next)) printf(" ***DELETED***");
+      printf("}\n");
+    }
+    else
+    {
+      /*printf("0x%08x { dummy }\n", el->hashnr);*/
+      DBUG_ASSERT(el->resource == 0 && el->loid == 0 && el->lock == X);
+    }
+    el= PTR(next);
+  }
+}
+#endif