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tdb: suppress record write locks when allrecord lock is taken.

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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>

(Imported from commit caaf5c6baa)

(This used to be ctdb commit 7a99cdf5d0a91764a750c1a264e90e5b66f910a1)
This commit is contained in:
Rusty Russell 2010-04-22 13:54:05 +09:30
parent 4ae716d1e9
commit 6f220bff0f
1 changed files with 9 additions and 0 deletions
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9
ctdb/lib/tdb/common/lock.c
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@ -631,11 +631,20 @@ int tdb_write_lock_record(struct tdb_context *tdb, tdb_off_t off)
for (i = &tdb->travlocks; i; i = i->next)
if (i->off == off)
return -1;
if (tdb->allrecord_lock.count) {
if (tdb->allrecord_lock.ltype == F_WRLCK) {
return 0;
}
return -1;
}
return tdb->methods->brlock(tdb, F_WRLCK, off, 1, TDB_LOCK_NOWAIT|TDB_LOCK_PROBE);
}
int tdb_write_unlock_record(struct tdb_context *tdb, tdb_off_t off)
{
if (tdb->allrecord_lock.count) {
return 0;
}
return tdb->methods->brunlock(tdb, F_WRLCK, off, 1);
}