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Re: [PATCH] tmp-objdir: do not opendir() when handling a signal

From
Jeff King <peff@peff.net>
Date
Sep 27, 2022, 11:48 UTC
Message-ID
<YzLjKbLI13GN52R/@coredump.intra.peff.net>
In-Reply-To
<YzJBZ9QJWIv0hpXb@nand.local>
On Mon, Sep 26, 2022 at 08:18:47PM -0400, Taylor Blau wrote:
Show 5 quoted lines
> It does make me a little uneasy leaving the quarantine directory around
> via this path. So I wonder if we should be optimistically opening up the
> DIR handle? Calling unlink() in a signal is perfectly fine, so I'd think
> as long as we have an open DIR handle we could call readdir_r(), but I
> don't think we've discussed it before.

You'd need to hold multiple such DIRs, since the removal is recursive. It's easy-ish for the "pack" directory, but the sub-process index-pack may have created 00-ff directories, too. You'd have to pre-create and opendir() all of them.

I'm also not sure what timing guarantees we have. If I opendir() a directory, then wait a long time while somebody else creates entries, is a readdir() guaranteed to see those new entries?

-Peff
Previous: Taylor BlauNext: Junio C Hamano
Message 3 of 18 in “tmp-objdir: do not opendir() when handling a signal”
  1. tmp-objdir: do not opendir() when handling a signalJohn Cai via GitGitGadget, Sep 26, 2022
  2. Taylor BlauSep 27, 2022
  3. Jeff KingSep 27, 2022
  4. Junio C HamanoSep 27, 2022
  5. Phillip WoodSep 27, 2022
  6. Jeff KingSep 27, 2022
  7. John CaiSep 27, 2022
  8. Jeff KingSep 27, 2022
  9. Junio C HamanoSep 27, 2022
  10. tmp-objdir: skip clean up when handling a signalJohn Cai via GitGitGadget, Sep 27, 2022
  11. Jeff KingSep 27, 2022
  12. Jeff KingSep 27, 2022
  13. tmp-objdir: skip clean up when handling a signalJohn Cai via GitGitGadget, Sep 28, 2022
  14. Ævar Arnfjörð BjarmasonSep 28, 2022
  15. tmp-objdir: skip clean up when handling a signalJohn Cai via GitGitGadget, Sep 30, 2022
  16. Jeff KingOct 3, 2022
  17. Another possible instance of async-signal-safe opendir path callstack? (Was: [PATCH] tmp-objdir: do not opendir() when handling a signal)Jan Pokorný, Oct 20, 2022
  18. Jeff KingOct 20, 2022

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