[SSSD] [PATCH 3/3] mmap cache: invalidate cache on fatal error
Simo Sorce
simo at redhat.com
Thu Dec 20 13:20:40 UTC 2012
On Thu, 2012-12-20 at 12:29 +0100, Pavel Březina wrote:
> On 12/20/2012 06:10 AM, Simo Sorce wrote:
> > -static errno_t sss_mc_get_record(struct sss_mc_ctx *mcc,
> > +static errno_t sss_mc_get_record(struct sss_mc_ctx **_mcc,
> > size_t rec_len,
> > struct sized_string *key,
> > struct sss_mc_rec **_rec)
> > {
> > + struct sss_mc_ctx *mcc = *_mcc;
> > struct sss_mc_rec *old_rec = NULL;
> > struct sss_mc_rec *rec;
> > int old_slots;
> > @@ -424,6 +425,16 @@ static errno_t sss_mc_get_record(struct sss_mc_ctx *mcc,
> > /* we are going to use more space, find enough free slots */
> > ret = sss_mc_find_free_slots(mcc, num_slots, &base_slot);
> > if (ret != EOK) {
> > + if (ret == EFAULT) {
> > + TALLOC_CTX *parent;
> > + DEBUG(SSSDBG_CRIT_FAILURE,
> > + ("Fatal internal mmap cache error, invalidating cache!\n"));
> > + parent = talloc_parent(mcc);
> > + if (parent == NULL) {
> > + talloc_zfree(*_mcc);
> > + }
> > + (void)sss_mmap_cache_reinit(parent, -1, -1, _mcc);
> > + }
> > return ret;
> > }
>
> Hi,
>
> Is if (parent == NULL) only precaution or can it actually happen?
Only a precaution, all the callers use an actual memory context.
> If you talloc_zfree(*_mcc) then you will hit EINVAL in reinit() and the
> cache won't be reinitialized. Is this intentional? If so, can you
> comment it in the code?
Well it was not intentional I meant to return after the free.
However I am wondering if we should really care ...
If the caller had NULL as the parent something may have gone wrong, but
at worst we will leak a few bytes... maybe I shouldn't consider a NULL
parent as an error after all. Opinions ?
Simo.
--
Simo Sorce * Red Hat, Inc * New York
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