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2010-02-24tdb: suppress record write locks when allrecord lock is taken.Rusty Russell1-0/+9
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>
2010-02-24tdb: cleanup: always grab allrecord lock to infinity.Rusty Russell1-7/+3
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>
2010-02-17tdb: remove num_locksRusty Russell2-11/+2
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>
2010-02-17tdb: use tdb_nest_lock() for seqnum lock.Rusty Russell1-3/+3
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>
2010-02-24tdb: use tdb_nest_lock() for active lock.Rusty Russell2-5/+18
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>
2010-02-22tdb: use tdb_nest_lock() for open lock.Rusty Russell3-15/+10
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>
2010-02-17tdb: use tdb_nest_lock() for transaction lock.Rusty Russell2-32/+23
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>
2010-02-17tdb: cleanup: find_nestlock() helper.Rusty Russell1-28/+23
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>
2010-02-24tdb: cleanup: tdb_release_extra_locks() helperRusty Russell3-17/+22
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>
2010-02-17tdb: cleanup: tdb_have_extra_locks() helperRusty Russell4-5/+17
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>
2010-02-17tdb: don't suppress the transaction lock because of the allrecord lock.Rusty Russell1-6/+0
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>
2010-02-17tdb: cleanup: tdb_nest_lock/tdb_nest_unlockRusty Russell3-45/+67
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>
2010-02-17tdb: cleanup: rename global_lock to allrecord_lock.Rusty Russell5-29/+29
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>
2010-02-17tdb: cleanup: rename GLOBAL_LOCK to OPEN_LOCK.Rusty Russell3-17/+17
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>
2010-02-24tdb: make _tdb_transaction_cancel static.Rusty Russell2-2/+1
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>
2010-02-17tdb: cleanup: split brlock and brunlock methods.Rusty Russell7-117/+235
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>
2010-02-22Spelling fixes for tdb.Brad Hards2-2/+2
Signed-off-by: Matthias Dieter Wallnöfer <mwallnoefer@yahoo.de>
2010-02-13tdb: use fdatasync() instead of fsync() in transactionsAndrew Tridgell1-1/+1
This might help on some filesystems
2010-02-13tdb: Apply some const, just for clarityVolker Lendecke1-1/+1
2010-02-10tdb: fix recovery reuse after crashRusty Russell1-4/+10
If a process (or the machine) dies after just after writing the recovery head (pointing at the end of file), the recovery record will filled with 0x42. This will not invoke a recovery on open, since rec.magic != TDB_RECOVERY_MAGIC. Unfortunately, the first transaction commit will happily reuse that area: tdb_recovery_allocate() doesn't check the magic. The recovery record has length 0x42424242, and it writes that back into the now-valid-looking transaction header) for the next comer (which happens to be tdb_wipe_all in my tests). Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-02-10tdb: give a name to the invalid recovery area constant (0)Rusty Russell3-4/+5
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-02-01tdb: fix an early release of the global lock that can cause data corruptionVolker Lendecke1-5/+10
There was a bug in tdb where the tdb_brlock(tdb, GLOBAL_LOCK, F_UNLCK, F_SETLKW, 0, 1); (ending the transaction-"mutex") was done before the /* remove the recovery marker */ This means that when a transaction is committed there is a window where another opener of the file sees the transaction marker while the transaction committer is still fully functional and working on it. This led to transaction being rolled back by that second opener of the file while transaction_commit() gave no error to the caller. This patch moves the F_UNLCK to after the recovery marker was removed, closing this window.
2009-11-20tdb: add TDB_DISALLOW_NESTING and make TDB_ALLOW_NESTING the default behaviorStefan Metzmacher3-3/+58
We need to keep TDB_ALLOW_NESTING as default behavior, so that existing code continues to work. However we may change the default together with a major version number change in future. metze
2009-11-20New attempt at TDB transaction nesting allow/disallow.Ronnie Sahlberg1-0/+11
Make the default be that transaction is not allowed and any attempt to create a nested transaction will fail with TDB_ERR_NESTING. If an application can cope with transaction nesting and the implicit semantics of tdb_transaction_commit(), it can enable transaction nesting by using the TDB_ALLOW_NESTING flag. (cherry picked from ctdb commit 3e49e41c21eb8c53084aa8cc7fd3557bdd8eb7b6) Signed-off-by: Stefan Metzmacher <metze@samba.org>
2009-11-20tdb: always set tdb->tracefd to -1 to be safe on goto failStefan Metzmacher1-4/+3
metze
2009-11-08tdb: Fix a C++ warningVolker Lendecke1-1/+2
2009-10-29tdb: reset tdb->fd to -1 in tdb_close()Kirill Smelkov1-1/+3
So that erroneous double tdb_close() calls do not try to close() same fd again. This is like SAFE_FREE() but for fd. Signed-off-by: Kirill Smelkov <kirr@mns.spb.ru> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2009-10-25tdb: detect tdb store of identical records and skipAndrew Tridgell1-0/+20
This can help with ldb where we rewrite the index records
2009-10-23tdb: rename 'struct list_struct' into 'struct tdb_record'Stefan Metzmacher9-54/+54
metze
2009-10-22lib/tdb: add tdb_check()Rusty Russell1-0/+422
ctdb wants a quick way to detect corrupt tdbs; particularly, tdbs with loops in their hash chains. tdb_check() provides this. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2009-10-22lib/tdb: wean off TDB_ERRCODE.Rusty Russell8-38/+59
It was a regrettable hack which I used to reduce line count in tdb; in fact it caused confusion as can be seen in this patch. In particular, ecode now needs to be set before TDB_LOG anyway, and having it exposed in the header is useless (the struct tdb_context isn't defined, so it's doubly useless). Also, we should never set errno, as io.c was doing. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2009-10-22lib/tdb: TDB_TRACE support (for developers)Rusty Russell6-55/+356
When TDB_TRACE is defined (in tdb_private.h), verbose tracing of tdb operations is enabled. This can be replayed using "replay_trace" from http://ccan.ozlabs.org/info/tdb. The majority of this patch comes from moving internal functions to _<funcname> to avoid double-tracing. There should be no additional overhead for the normal (!TDB_TRACE) case. Note that the verbose traces compress really well with rzip. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2009-09-15tdb: allow reads after prepare commitAndrew Tridgell1-8/+0
We previously only allowed a commit to happen after a prepare commit. It is in fact safe to allow reads between a prepare and a commit, and the s4 replication code can make use of that, so allow it.
2009-09-07tdb: fix c++ build warning.Günther Deschner1-2/+2
Guenther
2009-08-28lib/tdb: don't overwrite TDBs with different version numbers.Rusty Russell1-5/+7
In future, this may happen, and we don't want to clobber them. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2009-08-06Add define guards around otherwise unused variable.Jeremy Allison1-0/+3
Jeremy.
2009-08-06There is one signedness issue in tdb which prevents traverses of TDB recordsRusty Russell1-9/+21
over the 2G offset on systems which support 64 bit file offsets. This fixes that case. On systems with 32 bit offsets, expansion and fcntl locking on these records will fail anyway. SAMBA already does '#define _FILE_OFFSET_BITS 64' in config.h (on my 32-bit x86 Linux system at least) to get 64 bit file offsets. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2009-07-31tdb: don't alter tdb->flags in tdb_reopen_all()Rusty Russell1-6/+13
The flags are user-visible, via tdb_get_flags/add_flags/remove_flags. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Stefan Metzmacher <metze@samba.org>
2009-07-31tdb: Reimplementation of Metze's "lib/tdb: if we know pwrite and pread are ↵Rusty Russell1-5/+10
thread/fork safe tdb_reopen_all() should be a noop". This version just wraps the reopen code, so we still re-grab the lock and do the normal sanity checks. The reason we do this at all is to avoid global fd limits, see: http://forums.fedoraforum.org/showthread.php?t=210393 Note also that this whole reopen concept is fundamentally racy: if the parent goes away before the child calls tdb_reopen_all, the database can be left without an active lock and another TDB_CLEAR_IF_FIRST opener will clear it. A fork_with_tdbs() wrapper could use a pipe to solve this, but it's hardly elegant (what if there are other independent things which have similar needs?). Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Stefan Metzmacher <metze@samba.org>
2009-07-31tdb: Revert "lib/tdb: if we know pwrite and pread are thread/fork safe ↵Rusty Russell1-5/+0
tdb_reopen_all() should be a noop" This reverts commit e17df483fbedb81aededdef5fbb6ae1d034bc2dd. tdb_reopen_all also restores the active lock, required for TDB_CLEAR_IF_FIRST. Signed-off-by: Stefan Metzmacher <metze@samba.org>
2009-07-30realloc() has that horrible overloaded free semantic when size is 0:Rusty Russell1-2/+7
current code does a free of the old record in this case, then fail.
2009-07-30If the record is at the end of the database, pretending it has length 1Rusty Russell1-4/+1
might take us out-of-bounds. Only pretend to be length 1 for the malloc.
2009-07-21tdb: fix locking errorRusty Russell1-1/+1
54a51839ea65aa788b18fce8de0ae4f9ba63e4e7 "Make tdb transaction lock recursive (samba version)" was broken: I "cleaned it up" and prevented it from ever unlocking. To see the problem: $ bin/tdbtorture -s 1248142523 tdb_brlock failed (fd=3) at offset 8 rw_type=1 lck_type=14 len=1 tdb_transaction_lock: failed to get transaction lock tdb_transaction_start failed: Resource deadlock avoided My testcase relied on the *count* being correct, which it was. Fixing that now. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Michael Adam <obnox@samba.org>
2009-07-20Make tdb transaction lock recursive (samba version)Rusty Russell3-21/+20
This patch replaces 6ed27edbcd3ba1893636a8072c8d7a621437daf7 and 1a416ff13ca7786f2e8d24c66addf00883e9cb12, which fixed the bug where traversals inside transactions would release the transaction lock early. This solution is more general, and solves the more minor symptom that nested traversals would also release the transaction lock early. (It was also suggestd in Volker's comment in 6ed27ed). This patch also applies to ctdb, if the traverse.c part is removed (ctdb's tdb code never received the previous two fixes). Tested using the testsuite from ccan (adapted to the samba code). Thanks to Michael Adam for feedback. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Michael Adam <obnox@samba.org>
2009-06-01overallocate all records by 25%Andrew Tridgell1-0/+3
This greatly reduces the fragmentation of databases where records tend to grow slowly by a small amount each time. The case where this is most seen is the ldb index records. Adding this overallocation reduced the size of the resulting database by more than 20x when running a test that adds 10k users.
2009-06-01auto-repack in transactions that expand the tdbAndrew Tridgell1-0/+12
The idea behind this is to recover from badly fragmented free lists. Choosing the point where the file expands is fairly arbitrary, but seems to work well.
2009-05-28make TDB_NOSYNC affect all the fsync/msync calls in transactionsAndrew Tridgell1-5/+7
During a transaction commit tdb normally uses fsync/msync calls to make it crash safe. This can be disabled using the TDB_NOSYNC flag, but it wasn't disabling all the code paths that caused a fsync/msync.
2009-05-21Detect tight loop in tdb_find()Jim McDonough1-0/+5
2009-03-31tdb: Remove unused variableTim Prouty1-1/+0
2009-03-31Add tdb_transaction_prepare_commit()Howard Chu1-52/+124
Using tdb_transaction_prepare_commit() gives us 2-phase commits. This allows us to safely commit across multiple tdb databases at once, with reasonable transaction semantics Signed-off-by: tridge@samba.org
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