[dm-devel] [PATCH v2] multipath: Fix kpartx and udevd race
Benjamin Marzinski
bmarzins at redhat.com
Thu Jan 10 20:56:07 UTC 2013
Sometimes when kpartx is used to view partition data on disk image files,
udev still has the loop device open when kpartx is trying to tear it down.
This causes the LOOP_CLR_FD ioctl to fail with EBUSY. kpartx now retries
in this case.
Signed-off-by: Benjamin Marzinski <bmarzins at redhat.com>
---
kpartx/lopart.c | 16 ++++++++++++----
1 file changed, 12 insertions(+), 4 deletions(-)
Index: multipath-tools-130107/kpartx/lopart.c
===================================================================
--- multipath-tools-130107.orig/kpartx/lopart.c
+++ multipath-tools-130107/kpartx/lopart.c
@@ -286,6 +286,7 @@ set_loop (const char *device, const char
extern int
del_loop (const char *device)
{
+ int retries = 3;
int fd;
if ((fd = open (device, O_RDONLY)) < 0) {
@@ -295,10 +296,17 @@ del_loop (const char *device)
return 1;
}
- if (ioctl (fd, LOOP_CLR_FD, 0) < 0) {
- perror ("ioctl: LOOP_CLR_FD");
- close (fd);
- return 1;
+ while (ioctl (fd, LOOP_CLR_FD, 0) < 0) {
+ if (errno != EBUSY || retries-- <= 0) {
+ perror ("ioctl: LOOP_CLR_FD");
+ close (fd);
+ return 1;
+ }
+ fprintf(stderr,
+ "loop: device %s still in use, retrying delete\n",
+ device);
+ sleep(1);
+ continue;
}
close (fd);
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