==> Regarding Re: [patch] get rid of is_mounted checks in cache_clean; Ian Kent
<[EMAIL PROTECTED]> adds:
raven> On Tue, 26 Apr 2005, Jeff Moyer wrote:
>> ==> Regarding Re: [patch] get rid of is_mounted checks in cache_clean;
>> Ian Kent <[EMAIL PROTECTED]> adds:
>>
raven> On Mon, 25 Apr 2005, Jeff Moyer wrote:
>> >> Hi, Ian,
>> >>
>> >> I'm not sure what purpose the following check serves in the
>> cache_clean >> function:
>> >>
>> >> if (is_mounted(_PATH_MOUNTED, path)) { free(path); continue; }
>> >>
>> >> In the event that the map was updated, we signal the daemon to do a
>> >> re-read of the entire map. If the mount finishes before the daemon
>> is >> able to process this signal, we end up not pruning the old entry
>> for the >> given path. Now, because we append entries to the cache, we
>> end up with >> the stale entry first, followed by the updated entry.
>> This means that >> subsequent lookups will give the old entry.
>>
raven> This was originally meant to stop busy (currently mounted) entries
raven> from disappearing from the cache.
>>
raven> I'll check whether this is actually needed and get back.
>>
raven> One thing that comes to mind is that the direct mount rework design
raven> might need this.
>> Well, unfortunately I cannot comment on that. We had have a very
>> precise definite of what it means to be in the cache, then, if there are
>> to be side-effects of removing entries.
>>
>> Anyway, the patch I sent was somewhat incomplete. Look at this:
>>
>> if (me->age < age) {
pred-> next = me->next;
>> free(me->key); free(me->mapent); free(me); me = pred; rmdir_path(path);
>> }
>>
>> The rmdir_path is unneeded, and I would argue has no business being
>> here. It is the job of the umount_multi code to clean up the directory
>> tree, not the cache code. Lucky for us, the umount_multi path doesn't
>> error out if a directory is removed for it (thinking of odd races,
>> here). Anyway, the attached patch (diffed against current cvs) is more
>> complete in this respect. It gets rid of these rmdir_path calls.
raven> I remember now why this is needed.
raven> The directory creation/removal isn't done at mount/umount for
raven> browsable maps. It's done when the map is updated.
A ha! That makes sense, so I guess we should do:
if (!is_mounted(path))
rmdir_path(path);
At least that is what I'm going with for now, since we have to get a
release out the door. I understand your concerns with the direct mount
rework, and so I definitely view this as a temporary fix.
Thanks,
Jeff
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