s3:dbwrap_watch: avoid recursion into dbwrap_do_locked() from dbwrap_watched_do_locke...

s3:dbwrap_watch: avoid recursion into dbwrap_do_locked() from dbwrap_watched_do_locked_{storev,delete}()

This avoids a lot of overhead!

Using smbtorture3 //foo/bar -U% local-g-lock-ping-pong -o 500000
under valgrind --tool=callgrind...

This change replaces this:

 6,877,542,529  PROGRAM TOTALS

   590,000,773  lib/tdb/common/lock.c:tdb_lock_list
   479,000,608  lib/tdb/common/lock.c:tdb_unlock
   446,500,532  lib/tdb/common/io.c:tdb_read
   364,000,824  lib/tdb/common/hash.c:tdb_jenkins_hash
   285,000,532  lib/tdb/common/io.c:tdb_write
   262,054,669  /x86_64/multiarch/memmove-vec-unaligned-erms.S:__memcpy_avx_unaligned_erms
   206,500,496  lib/tdb/common/mutex.c:tdb_mutex_lock
   193,000,176  lib/tdb/common/tdb.c:tdb_find
   160,000,256  lib/talloc/talloc.c:_talloc_get_type_abort
   148,500,297  lib/tdb/common/tdb.c:tdb_storev
   140,000,196  lib/tdb/common/lock.c:tdb_lock
   130,000,858  lib/util/debug.c:debuglevel_get_class
   128,003,722  lib/talloc/talloc.c:_talloc_free
   128,000,118  lib/tdb/common/tdb.c:tdb_parse_record
   126,000,576  lib/tdb/common/lock.c:tdb_brlock.part.3
   121,000,272  lib/tdb/common/mutex.c:tdb_mutex_unlock
   118,000,225  /nptl/pthread_mutex_lock.c:__pthread_mutex_lock_full
   112,750,222  lib/tdb/common/freelist.c:tdb_allocate_from_freelist
   108,500,168  lib/tdb/common/io.c:tdb_ofs_read
   102,500,000  lib/tdb/common/io.c:tdb_parse_data

by this:

 5,706,522,398  PROGRAM TOTALS

   434,000,617  lib/tdb/common/lock.c:tdb_lock_list
   389,500,494  lib/tdb/common/io.c:tdb_read
   359,000,488  lib/tdb/common/lock.c:tdb_unlock
   285,000,532  lib/tdb/common/io.c:tdb_write
   237,554,655  /x86_64/multiarch/memmove-vec-unaligned-erms.S:__memcpy_avx_unaligned_erms
   208,000,668  lib/tdb/common/hash.c:tdb_jenkins_hash
   206,500,496  lib/tdb/common/mutex.c:tdb_mutex_lock
   160,000,256  lib/talloc/talloc.c:_talloc_get_type_abort
   148,500,297  lib/tdb/common/tdb.c:tdb_storev
   136,000,132  lib/tdb/common/tdb.c:tdb_find
   130,000,858  lib/util/debug.c:debuglevel_get_class
   126,000,576  lib/tdb/common/lock.c:tdb_brlock.part.3
   121,000,272  lib/tdb/common/mutex.c:tdb_mutex_unlock
   118,000,225  /nptl/pthread_mutex_lock.c:__pthread_mutex_lock_full
   112,750,222  lib/tdb/common/freelist.c:tdb_allocate_from_freelist
   112,000,168  lib/tdb/common/lock.c:tdb_lock
    94,500,154  lib/tdb/common/io.c:tdb_ofs_read
    94,000,188  /nptl/pthread_mutex_unlock.c:__pthread_mutex_unlock_full
    86,000,086  lib/dbwrap/dbwrap.c:dbwrap_lock_order_lock
    83,000,083  lib/dbwrap/dbwrap_tdb.c:db_tdb_do_locked

time smbtorture3 //foo/bar -U% local-g-lock-ping-pong -o 5000000

gives:

  902834 locks/sec

 real    0m11,103s
 user    0m8,233s
 sys     0m2,868s

vs.

 1037262 locks/sec

 real    0m9,685s
 user    0m6,788s
 sys     0m2,896s

Signed-off-by: Stefan Metzmacher <metze@samba.org>
Reviewed-by: Volker Lendecke <vl@samba.org>
Autobuild-User(master): Volker Lendecke <vl@samba.org>
Autobuild-Date(master): Wed Jul  8 11:02:39 UTC 2020 on sn-devel-184