42 lines
1.4 KiB
Diff
42 lines
1.4 KiB
Diff
From 41af4459ac47e107093c3f54b6875d54723aa613 Mon Sep 17 00:00:00 2001
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From: Sebastian Hasler <sebastian.hasler@stuvus.uni-stuttgart.de>
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Date: Thu, 13 Jan 2022 16:32:49 +0100
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Subject: [PATCH 2/2] virtiofsd: Do not support blocking flock
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With the current implementation, blocking flock can lead to
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deadlock. Thus, it's better to return EOPNOTSUPP if a user attempts
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to perform a blocking flock request.
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Signed-off-by: Sebastian Hasler <sebastian.hasler@stuvus.uni-stuttgart.de>
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Message-Id: <20220113153249.710216-1-sebastian.hasler@stuvus.uni-stuttgart.de>
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Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
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Reviewed-by: Vivek Goyal <vgoyal@redhat.com>
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Reviewed-by: Greg Kurz <groug@kaod.org>
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---
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tools/virtiofsd/passthrough_ll.c | 9 +++++++++
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1 file changed, 9 insertions(+)
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diff --git a/tools/virtiofsd/passthrough_ll.c b/tools/virtiofsd/passthrough_ll.c
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index b3d0674f6d..3e56d1cd95 100644
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--- a/tools/virtiofsd/passthrough_ll.c
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+++ b/tools/virtiofsd/passthrough_ll.c
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@@ -2467,6 +2467,15 @@ static void lo_flock(fuse_req_t req, fuse_ino_t ino, struct fuse_file_info *fi,
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int res;
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(void)ino;
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+ if (!(op & LOCK_NB)) {
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+ /*
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+ * Blocking flock can deadlock as there is only one thread
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+ * serving the queue.
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+ */
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+ fuse_reply_err(req, EOPNOTSUPP);
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+ return;
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+ }
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+
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res = flock(lo_fi_fd(req, fi), op);
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fuse_reply_err(req, res == -1 ? errno : 0);
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--
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2.35.1
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