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- Function should accept pointer to drsuapi_DsReplicaSyncRequest.
While this doesn't generate essentially different code for
NDR parser, using pointer will make drsuapi_DsReplicaSync
descritpin with the rest of the functions in DRSUAPI interface.
Another benefit is that this way we could create Wireshark
dissector directly from Samba's verions for drsuapi.idl
- 'level' and thus the switch_type() should be uint32
- pointer to naming_context should be [ref] pointer
(i.e. not NULL pointer)
- other_info is actually the DNS name for Source DSA and is used
if DRSUAPI_DRS_SYNC_BYNAME is passed
ref: [MS-DRSR] 5.39
tdb transactions were designed to be robust against the machine
powering off, but interestingly were never designed to handle the case
where an administrator kill -9's a process during commit. Because
recovery is only done on tdb_open, processes with the tdb already
mapped will simply use it despite it being corrupt and needing
recovery.
The solution to this is to check for recovery every time we grab a
data lock: we could have gained the lock because a process just died.
This has no measurable cost: here is the time for tdbtorture -s 0 -n 1
-l 10000:
Before:
2.75 2.50 2.81 3.19 2.91 2.53 2.72 2.50 2.78 2.77 = Avg 2.75
After:
2.81 2.57 3.42 2.49 3.02 2.49 2.84 2.48 2.80 2.43 = Avg 2.74
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
To test the case of death of a process during transaction commit, add
a -k (kill random) option to tdbtorture. The easiest way to do this
is to make every worker a child (unless there's only one child), which
is why this patch is bigger than you might expect.
Using -k without -t (always transactions) you expect corruption, though
it doesn't happen every time. With -t, we currently get corruption but
the next patch fixes that.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
The current recovery code truncates the tdb file on recovery. This is
fine if recovery is only done on first open, but is a really bad idea
as we move to allowing recovery on "live" databases.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Now the transaction code uses the standard allrecord lock, that stops
us from trying to grab any per-record locks anyway. We don't need to
have special noop lock ops for transactions.
This is a nice simplification: if you see brlock, you know it's really
going to grab a lock.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
tdb_release_extra_locks() is too general: it carefully skips over the
transaction lock, even though the only caller then drops it. Change
this, and rename it to show it's clearly transaction-specific.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Now the transaction allrecord lock is the standard one, and thus is cleaned
in tdb_release_extra_locks(), _tdb_transaction_cancel() doesn't need to
know what type it is.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Centralize locking of all chains of the tdb; rename _tdb_lockall to
tdb_allrecord_lock and _tdb_unlockall to tdb_allrecord_unlock, and
tdb_brlock_upgrade to tdb_allrecord_upgrade.
Then we use this in the transaction code. Unfortunately, if the transaction
code records that it has grabbed the allrecord lock read-only, write locks
will fail, so we treat this upgradable lock as a write lock, and mark it
as upgradable using the otherwise-unused offset field.
One subtlety: now the transaction code is using the allrecord_lock, the
tdb_release_extra_locks() function drops it for us, so we no longer need
to do it manually in _tdb_transaction_cancel.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Records themselves get (read) locked by the traversal code against delete.
Interestingly, this locking isn't done when the allrecord lock has been
taken, though the allrecord lock until recently didn't cover the actual
records (it now goes to end of file).
The write record lock, grabbed by the delete code, is not suppressed
by the allrecord lock. This is now bad: it causes us to punch a hole
in the allrecord lock when we release the write record lock. Make this
consistent: *no* record locks of any kind when the allrecord lock is
taken.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
We were previously inconsistent with our "global" lock: the
transaction code grabbed it from FREELIST_TOP to end of file, and the
rest of the code grabbed it from FREELIST_TOP to end of the hash
chains. Change it to always grab to end of file for simplicity and
so we can merge the two.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This was redundant before this patch series: it mirrored num_lockrecs
exactly. It still does.
Also, skip useless branch when locks == 1: unconditional assignment is
cheaper anyway.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This is pure overhead, but it centralizes the locking. Realloc (esp. as
most implementations are lazy) is fast compared to the fnctl anyway.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Use our newly-generic nested lock tracking for the active lock.
Note that the tdb_have_extra_locks() and tdb_release_extra_locks()
functions have to skip over this lock now it is tracked.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This never nests, so it's overkill, but it centralizes the locking into
lock.c and removes the ugly flag in the transaction code to track whether
we have the lock or not.
Note that we have a temporary hack so this places a real lock, despite
the fact that we are in a transaction.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Rather than a boutique lock and a separate nest count, use our
newly-generic nested lock tracking for the transaction lock.
Note that the tdb_have_extra_locks() and tdb_release_extra_locks()
functions have to skip over this lock now it is tracked.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Factor out two loops which find locks; we are going to introduce a couple
more so a helper makes sense.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Move locking intelligence back into lock.c, rather than open-coding the
lock release in transaction.c.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
In many places we check whether locks are held: add a helper to do this.
The _tdb_lockall() case has already checked for the allrecord lock, so
the extra work done by tdb_have_extra_locks() is merely redundant.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
tdb_transaction_lock() and tdb_transaction_unlock() do nothing if we
hold the allrecord lock. However, the two locks don't overlap, so
this is wrong.
This simplification makes the transaction lock a straight-forward nested
lock.
There are two callers for these functions:
1) The transaction code, which already makes sure the allrecord_lock
isn't held.
2) The traverse code, which wants to stop transactions whether it has the
allrecord lock or not. There have been deadlocks here before, however
this should not bring them back (I hope!)
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Because fcntl locks don't nest, we track them in the tdb->lockrecs array
and only place/release them when the count goes to 1/0. We only do this
for record locks, so we simply place the list number (or -1 for the free
list) in the structure.
To generalize this:
1) Put the offset rather than list number in struct tdb_lock_type.
2) Rename _tdb_lock() to tdb_nest_lock, make it non-static and move the
allrecord check out to the callers (except the mark case which doesn't
care).
3) Rename _tdb_unlock() to tdb_nest_unlock(), make it non-static and
move the allrecord out to the callers (except mark again).
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
The word global is overloaded in tdb. The global_lock inside struct
tdb_context is used to indicate we hold a lock across all the chains.
Rename it to allrecord_lock.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
The word global is overloaded in tdb. The GLOBAL_LOCK offset is used at
open time to serialize initialization (and by the transaction code to block
open).
Rename it to OPEN_LOCK.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Now tdb_open() calls tdb_transaction_cancel() instead of
_tdb_transaction_cancel, we can make it static.
Signed-off-by: Rusty Russell<rusty@rustcorp.com.au>
This is taken from the CCAN code base: rather than using tdb_brlock for
locking and unlocking, we split it into brlock and brunlock functions.
For extra debugging information, brunlock says what kind of lock it is
unlocking (even though fnctl locks don't need this). This requires an
extra argument to tdb_transaction_unlock() so we know whether the
lock was upgraded to a write lock or not.
We also use a "flags" argument tdb_brlock:
1) TDB_LOCK_NOWAIT replaces lck_type = F_SETLK (vs F_SETLKW).
2) TDB_LOCK_MARK_ONLY replaces setting TDB_MARK_LOCK bit in ltype.
3) TDB_LOCK_PROBE replaces the "probe" argument.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
msDS-IntId attribute should be replicated, so it must be
implemented in a module that is before repl_meta_data module
(thanks abartlet for pointing this out).
Signed-off-by: Andrew Bartlett <abartlet@samba.org>
After looking at the s4 side of the (s)channel :) I found out that it makes
more sense to simply make it use the tdb based code than redo the same changes
done to s3 to simplify the interface.
Ldb is slow, to the point it needs haks to pre-open the db to speed it up, yet
that does not solve the lookup speed, with ldb it is always going to be slower.
Looking through the history it is evident that the schannel database doesn't
really need greate expanadability. And lookups are always done with a single
Key. This seem a perfet fit for tdb while ldb looks unnecessarily complicated.
The schannel database is not really a persistent one. It can be discared during
an upgrade without causing any real issue. all it contains is temproary session
data.
