Justin Erenkrantz wrote:
Sander Striker wrote:
I completely agree. So much even that I just committed it (r156306).
Why are we storing the header fd in the disk object anyways? I haven't
gone through mod_disk_cache.c yet, but at least for store_headers() it
doesn't seem to make any sense.
It's not really the 'disk' object per se - it's part of mod_disk_cache's
private cache handle. When we open the cache handle, we also open the
associated file descriptors in open_entity to ensure that we have
something valid cached. We then use those open descriptors in
recall_headers and recall_body later on.
Right.
Note that we're a little tricky and we partially read the header file in
open_entity to get some meta-data via file_cache_recall_mydata, but we
hold off parsing the full MIME headers from disk until recall_headers time.
Gotcha.
When it comes to store_headers(), shouldn't that be done using a temp
file and moving it into place atomically just like store_body? Are
we relying on OS buffering and header size being small enough to pull
that off? Or am I just being paranoid? :)
Yes, there's probably a race condition here. However, store_headers is
only called once, so the window is relatively small compared to
store_body which can be called multiple times. Feel free to have at
it. ;-)
*grin* Will do.
Sander
- Re: mod_cache Sander Striker
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