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r24642: prevent recursion with fetch_locked

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add a note about server_id exists checking
This commit is contained in:
Andrew Tridgell 2007-08-24 02:37:38 +00:00 committed by Gerald (Jerry) Carter
parent aa0a348964
commit dd951b983c
1 changed files with 22 additions and 10 deletions
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32
source/ntvfs/common/brlock_tdb.c
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@ -135,9 +135,12 @@ static BOOL brl_tdb_same_context(struct lock_context *ctx1, struct lock_context
/*
see if lck1 and lck2 overlap
lck1 is the existing lock. lck2 is the new lock we are
looking at adding
*/
static BOOL brl_tdb_overlap(struct lock_struct *lck1,
struct lock_struct *lck2)
struct lock_struct *lck2)
{
/* this extra check is not redundent - it copes with locks
that go beyond the end of 64 bit file space */
@ -151,6 +154,15 @@ static BOOL brl_tdb_overlap(struct lock_struct *lck1,
lck2->start >= (lck1->start+lck1->size)) {
return False;
}
/* we have a conflict. Now check to see if lck1 really still
* exists, which involves checking if the process still
* exists. We leave this test to last as its the most
* expensive test, especially when we are clustered */
/* TODO: need to do this via a server_id_exists() call, which
* hasn't been written yet. When clustered this will need to
* call into ctdb */
return True;
}
@ -283,14 +295,6 @@ static NTSTATUS brl_tdb_lock(struct brl_context *brl,
NTSTATUS status;
struct db_record *rec = NULL;
kbuf.dptr = brlh->key.data;
kbuf.dsize = brlh->key.length;
rec = brl->db->fetch_locked(brl->db, brl, kbuf);
if (rec == NULL) {
return NT_STATUS_INTERNAL_DB_CORRUPTION;
}
/* if this is a pending lock, then with the chainlock held we
try to get the real lock. If we succeed then we don't need
to make it pending. This prevents a possible race condition
@ -305,11 +309,19 @@ static NTSTATUS brl_tdb_lock(struct brl_context *brl,
brlh->last_lock = lock;
if (NT_STATUS_IS_OK(status)) {
talloc_free(rec);
return NT_STATUS_OK;
}
}
kbuf.dptr = brlh->key.data;
kbuf.dsize = brlh->key.length;
rec = brl->db->fetch_locked(brl->db, brl, kbuf);
if (rec == NULL) {
return NT_STATUS_INTERNAL_DB_CORRUPTION;
}
dbuf = rec->value;
lock.context.smbpid = smbpid;