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70 lines
2.8 KiB
70 lines
2.8 KiB
From e55efa99fd829a4699aae6505e02fae7b50a40bc Mon Sep 17 00:00:00 2001 |
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From: Daniel Drake <drake@endlessm.com> |
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Date: Mon, 6 Apr 2015 16:03:43 -0600 |
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Subject: [PATCH] udevd: fix synchronization with settle when handling inotify |
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events |
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udev uses inotify to implement a scheme where when the user closes |
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a writable device node, a change uevent is forcefully generated. |
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In the case of block devices, it actually requests a partition rescan. |
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This currently can't be synchronized with "udevadm settle", i.e. this |
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is not reliable in a script: |
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sfdisk --change-id /dev/sda 1 81 |
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udevadm settle |
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mount /dev/sda1 /foo |
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The settle call doesn't synchronize there, so at the same time we try |
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to mount the device, udevd is busy removing the partition device nodes and |
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readding them again. The mount call often happens in that moment where the |
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partition node has been removed but not readded yet. |
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This exact issue was fixed long ago: |
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http://git.kernel.org/cgit/linux/hotplug/udev.git/commit/?id=bb38678e3ccc02bcd970ccde3d8166a40edf92d3 |
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but that fix is no longer valid now that sequence numbers are no longer |
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used. |
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Fix this by forcing another mainloop iteration after handling inotify events |
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before unblocking settle. If the inotify event caused us to generate a |
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"change" event, we'll pick that up in the following loop iteration, before |
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we reach the end of the loop where we respond to settle's control message, |
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unblocking it. |
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(cherry picked from commit 07ba8037bf2a2d6a683fa107ee6f2b9545fca23e) |
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Cherry-picked from: 7a2e024 |
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Resolves: #1222517 |
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--- |
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src/udev/udevd.c | 15 ++++++++++++++- |
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1 file changed, 14 insertions(+), 1 deletion(-) |
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diff --git a/src/udev/udevd.c b/src/udev/udevd.c |
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index e98c1fd6d..87a3f69e9 100644 |
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--- a/src/udev/udevd.c |
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+++ b/src/udev/udevd.c |
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@@ -1502,9 +1502,22 @@ int main(int argc, char *argv[]) { |
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continue; |
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/* device node watch */ |
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- if (is_inotify) |
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+ if (is_inotify) { |
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handle_inotify(udev); |
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+ /* |
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+ * settle might be waiting on us to determine the queue |
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+ * state. If we just handled an inotify event, we might have |
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+ * generated a "change" event, but we won't have queued up |
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+ * the resultant uevent yet. |
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+ * |
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+ * Before we go ahead and potentially tell settle that the |
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+ * queue is empty, lets loop one more time to update the |
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+ * queue state again before deciding. |
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+ */ |
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+ continue; |
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+ } |
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+ |
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/* tell settle that we are busy or idle, this needs to be before the |
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* PING handling |
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*/
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