samba.git/source3/lib/dbwrap, branch talloc-2.4.4

s3/dbwrap_watch: avoid leaking backend db handle in traverses

2025-08-05T14:52:34+00:00

Currently in a traverse callback dbwrap_record_get_db() returns the backend db
handle.

Signed-off-by: Ralph Boehme 
Reviewed-by: Stefan Metzmacher

dbwrap: check for option "tdb_hash_size:DBNAME.tdb" in db_open()

2025-04-02T18:05:47+00:00

BUG: https://bugzilla.samba.org/show_bug.cgi?id=15767

Signed-off-by: Ralph Boehme 
Reviewed-by: Stefan Metzmacher

lib: Remove timeval_set()

2024-03-22T06:07:42+00:00

We have the same function in tevent, no need to duplicate code. More lines just
due to clang-format.

Signed-off-by: Volker Lendecke 
Reviewed-by: Andrew Bartlett 

Autobuild-User(master): Andrew Bartlett 
Autobuild-Date(master): Fri Mar 22 06:07:42 UTC 2024 on atb-devel-224

s3:g_lock: add callback function to g_lock_lock()

2022-09-20T00:34:35+00:00

BUG: https://bugzilla.samba.org/show_bug.cgi?id=15125

Signed-off-by: Stefan Metzmacher 
Reviewed-by: Jeremy Allison

lib/dbwrap: allow dbwrap_merge_dbufs() to update an existing buffer

2022-09-20T00:34:35+00:00

This will be useful in future...

BUG: https://bugzilla.samba.org/show_bug.cgi?id=15125

Signed-off-by: Stefan Metzmacher 
Reviewed-by: Jeremy Allison

s3:dbwrap_watch: add dbwrap_watched_watch_force_alerting()

2022-09-20T00:34:35+00:00

This is useful when we want to wakeup the next watcher
without modifying the record.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=15125

Signed-off-by: Stefan Metzmacher 
Reviewed-by: Jeremy Allison

s3:dbwrap_watch: add dbwrap_watched_watch_reset_alerting() helper

2022-09-20T00:34:35+00:00

This can be used if the decision of using dbwrap_watched_watch_skip_alerting()
needs to be reverted...

BUG: https://bugzilla.samba.org/show_bug.cgi?id=15125

Signed-off-by: Stefan Metzmacher 
Reviewed-by: Jeremy Allison

s3:dbwrap_watch: let dbwrap_watched_watch_skip_alerting() also clear the selected watcher

2022-09-20T00:34:35+00:00

If a watcher was already selected for a wakeup notification reset it...

BUG: https://bugzilla.samba.org/show_bug.cgi?id=15125

Signed-off-by: Stefan Metzmacher 
Reviewed-by: Jeremy Allison

s3:dbwrap_watch: call dbwrap_watched_trigger_wakeup() outside of the low level record lock

2022-07-26T14:32:35+00:00

This gives a nice speed up, as it's unlikely for the waiters to hit
contention.

The following test with 256 commections all looping with open/close
on the same inode (share root) is improved drastically:

  smbtorture //127.0.0.1/m -Uroot%test smb2.create.bench-path-contention-shared \
     --option='torture:bench_path=' \
     --option="torture:timelimit=60" \
     --option="torture:nprocs=256"

From some like this:

   open[num/s=8800,avslat=0.021445,minlat=0.000095,maxlat=0.179786]
   close[num/s=8800,avslat=0.021658,minlat=0.000044,maxlat=0.179819]

to:

   open[num/s=10223,avslat=0.017922,minlat=0.000083,maxlat=0.106759]
   close[num/s=10223,avslat=0.017694,minlat=0.000040,maxlat=0.107345]

BUG: https://bugzilla.samba.org/show_bug.cgi?id=15125

Signed-off-by: Stefan Metzmacher 
Reviewed-by: Jeremy Allison 
Reviewed-by: Ralph Boehme 

Autobuild-User(master): Ralph Böhme 
Autobuild-Date(master): Tue Jul 26 14:32:35 UTC 2022 on sn-devel-184

s3:dbwrap_watch: only notify the first waiter

2022-07-26T13:40:34+00:00

In case of a highly contended record we will have a lot of watchers,
which will all race to get g_lock_lock() to finish.

If g_lock_unlock() wakes them all, e.g. 250 of them, we get a thundering
herd, were 249 will only find that one of them as able to get the lock
and re-add their watcher entry (not unlikely in a different order).

With this commit we only wake the first watcher and let it remove
itself once it no longer wants to monitor the record content
(at that time it will wake the new first watcher).

It means the woken watcher doesn't have to race with all others
and also means order of watchers is kept, which means that we
most likely get a fair latency distribution for all watchers.

The following test with 256 commections all looping with open/close
on the same inode (share root) is improved drastically:

  smbtorture //127.0.0.1/m -Uroot%test smb2.create.bench-path-contention-shared \
     --option='torture:bench_path=' \
     --option="torture:timelimit=60" \
     --option="torture:nprocs=256"

From some like this:

   open[num/s=80,avslat=2.793862,minlat=0.004097,maxlat=46.597053]
   close[num/s=80,avslat=2.387326,minlat=0.023875,maxlat=50.878165]

to:

   open[num/s=8800,avslat=0.021445,minlat=0.000095,maxlat=0.179786]
   close[num/s=8800,avslat=0.021658,minlat=0.000044,maxlat=0.179819]

BUG: https://bugzilla.samba.org/show_bug.cgi?id=15125

Signed-off-by: Stefan Metzmacher 
Reviewed-by: Jeremy Allison 
Reviewed-by: Ralph Boehme