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r10492: work around a bug in solaris which cases lock upgrades to fail with

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EDEADLK even when progress can be made. This is not a good solution,
but I can't find anything better.
(This used to be commit 980dd17f7d0a622cd772afc9ba15e50007ad9c6e)
This commit is contained in:
Andrew Tridgell 2005-09-26 01:12:12 +00:00 committed by Gerald (Jerry) Carter
parent 9593101ec1
commit be27946d84
3 changed files with 28 additions and 1 deletions
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26
source4/lib/tdb/common/lock.c
View File

@ -81,6 +81,32 @@ int tdb_brlock_len(struct tdb_context *tdb, tdb_off_t offset,
}
/*
upgrade a read lock to a write lock. This needs to be handled in a
special way as some OSes (such as solaris) have too conservative
deadlock detection and claim a deadlock when progress can be
made. For those OSes we may loop for a while.
*/
int tdb_brlock_upgrade(struct tdb_context *tdb, tdb_off_t offset, size_t len)
{
int count = 1000;
while (count--) {
struct timeval tv;
if (tdb_brlock_len(tdb, offset, F_WRLCK, F_SETLKW, 1, len) == 0) {
return 0;
}
if (errno != EDEADLK) {
break;
}
/* sleep for as short a time as we can - more portable than usleep() */
tv.tv_sec = 0;
tv.tv_usec = 1;
select(0, NULL, NULL, NULL, &tv);
}
return -1;
}
/* a byte range locking function - return 0 on success
this functions locks/unlocks 1 byte at the specified offset.

1
source4/lib/tdb/common/tdb_private.h
View File

@ -216,6 +216,7 @@ void tdb_mmap(struct tdb_context *tdb);
int tdb_lock(struct tdb_context *tdb, int list, int ltype);
int tdb_unlock(struct tdb_context *tdb, int list, int ltype);
int tdb_brlock(struct tdb_context *tdb, tdb_off_t offset, int rw_type, int lck_type, int probe);
int tdb_brlock_upgrade(struct tdb_context *tdb, tdb_off_t offset, size_t len);
int tdb_brlock_len(struct tdb_context *tdb, tdb_off_t offset,
int rw_type, int lck_type, int probe, size_t len);
int tdb_write_lock_record(struct tdb_context *tdb, tdb_off_t off);

2
source4/lib/tdb/common/transaction.c
View File

@ -772,7 +772,7 @@ int tdb_transaction_commit(struct tdb_context *tdb)
}
/* upgrade the main transaction lock region to a write lock */
if (tdb_brlock_len(tdb, FREELIST_TOP, F_WRLCK, F_SETLKW, 0, 0) == -1) {
if (tdb_brlock_upgrade(tdb, FREELIST_TOP, 0) == -1) {
TDB_LOG((tdb, 0, "tdb_transaction_start: failed to upgrade hash locks\n"));
tdb->ecode = TDB_ERR_LOCK;
tdb_transaction_cancel(tdb);