Re: udev git head: cdrom_id regression

[Harald Hoyer <harald@redhat.com>]

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Am 06.04.2010 14:26, schrieb Kay Sievers:
> On Tue, Apr 6, 2010 at 14:19, Martin Pitt<martin.pitt@ubuntu.com>  wrote:
>> Kay, do you know why [2] was done in the first place? Do you happen to
>> have a pointer to a bug etc. which describes the problems with CD
>> burning sessions?
>
> Harald said, he has several bugs with cd burning caused by cdrom_id
> and blkid opening the device when a uevent is handled during cd
> burning. I did not receive any such bug.
>
> Kay


https://bugzilla.redhat.com/show_bug.cgi?id=481346
https://bugzilla.redhat.com/show_bug.cgi?id=566535

We might want to apply the attached patches.

[-- Attachment #2: 0001-cdrom_id-remove-debugging-code.patch --]
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From 194c5c10b65499e52864132ed542845b4c2e757c Mon Sep 17 00:00:00 2001
From: Harald Hoyer <harald@redhat.com>
Date: Tue, 6 Apr 2010 14:34:32 +0200
Subject: [PATCH 1/2] cdrom_id: remove debugging code

---
 extras/cdrom_id/cdrom_id.c |    1 -
 1 files changed, 0 insertions(+), 1 deletions(-)

diff --git a/extras/cdrom_id/cdrom_id.c b/extras/cdrom_id/cdrom_id.c
index e485768..036ef28 100644
--- a/extras/cdrom_id/cdrom_id.c
+++ b/extras/cdrom_id/cdrom_id.c
@@ -126,7 +126,6 @@ static int is_mounted(const char *device)
 	if (fp == NULL)
 		return -ENOSYS;
 	while (fscanf(fp, "%*s %*s %i:%i %*[^\n]", &maj, &min) == 2) {
-		printf("got %u %u\n", maj, min);
 		if (makedev(maj, min) == statbuf.st_rdev) {
 			mounted = 1;
 			break;
-- 
1.6.6.1


[-- Attachment #3: 0002-cdrom_id-retry-to-open-the-device-if-EBUSY.patch --]
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From cb3d97513fec69c4f75cf24651a16404dd576da4 Mon Sep 17 00:00:00 2001
From: Harald Hoyer <harald@redhat.com>
Date: Tue, 6 Apr 2010 14:37:21 +0200
Subject: [PATCH 2/2] cdrom_id: retry to open the device, if EBUSY

---
 extras/cdrom_id/cdrom_id.c |   29 +++++++++++++++++++++++------
 1 files changed, 23 insertions(+), 6 deletions(-)

diff --git a/extras/cdrom_id/cdrom_id.c b/extras/cdrom_id/cdrom_id.c
index 036ef28..5e0ddba 100644
--- a/extras/cdrom_id/cdrom_id.c
+++ b/extras/cdrom_id/cdrom_id.c
@@ -591,12 +591,29 @@ int main(int argc, char *argv[])
 		goto exit;
 	}
 
-	fd = open(node, O_RDONLY|O_NONBLOCK|(is_mounted(node) ? 0 : O_EXCL));
-	if (fd < 0) {
-		info(udev, "unable to open '%s'\n", node);
-		fprintf(stderr, "unable to open '%s'\n", node);
-		rc = 1;
-		goto exit;
+
+	{
+		int errno_open=0;
+		int i = 0;
+
+		do {
+			int excl = is_mounted(node) ? 0 : O_EXCL;
+			fd = open(node, O_RDONLY|O_NONBLOCK|excl);
+			errno_open = errno;
+			if (fd < 0) {
+				if (errno_open != EBUSY || i >= 100) {
+					char *strerr = strerror(errno_open);
+					info(udev, "unable to open '%s': %s\n", node, strerr);
+					fprintf(stderr, "unable to open '%s': %s\n", node, strerr);
+					rc = 1;
+					goto exit;
+				} else {
+					fprintf(stderr, "unable to open '%s' exclusively: retrying (%d/100)\n", node, i);
+					usleep((useconds_t)(400000.0 + 400000.0 * rand() * 1.0 / (RAND_MAX+1.0)));
+					i++; 
+				}
+			}
+		} while ((fd < 0) && (errno_open == EBUSY));
 	}
 	info(udev, "probing: '%s'\n", node);
 
-- 
1.6.6.1