If md kernel module is reloaded, /proc/mdstat cannot be accessed ("cat:
/proc/mdstat: No such file or directory"). The reason is mdadm monitor
still holds a file descriptor to previous /proc/mdstat instance. It
leads to really confusing outcome of the following operations - mdadm
seems to run without errors, however some udev rules don't get executed
and new array doesn't work.
Add a check if lseek was successful as it fails if md kernel module has
been unloaded - close a file descriptor then. The problem is mdadm
monitor doesn't always do it before next operation takes place. To
prevent it monitor always releases /proc/mdstat descriptor when there
are no arrays to be monitored, just in case driver unload happens in a
moment.
Signed-off-by: Tomasz Majchrzak <tomasz.majchrzak@xxxxxxxxx>
Reviewed-by: Artur Paszkiewicz <artur.paszkiewicz@xxxxxxxxx>
---
Monitor.c | 2 ++
mdstat.c | 6 +++++-
2 files changed, 7 insertions(+), 1 deletion(-)
diff --git a/Monitor.c b/Monitor.c
index 4adc237..802a9d9 100644
--- a/Monitor.c
+++ b/Monitor.c
@@ -213,6 +213,8 @@ int Monitor(struct mddev_dev *devlist,
if (mdstat)
free_mdstat(mdstat);
mdstat = mdstat_read(oneshot?0:1, 0);
+ if (!mdstat)
+ mdstat_close();
for (st=statelist; st; st=st->next)
if (check_array(st, mdstat, c->test, &info,
diff --git a/mdstat.c b/mdstat.c
index 2972cdf..3962896 100644
--- a/mdstat.c
+++ b/mdstat.c
@@ -133,7 +133,11 @@ struct mdstat_ent *mdstat_read(int hold, int start)
int fd;
if (hold && mdstat_fd != -1) {
- lseek(mdstat_fd, 0L, 0);
+ off_t offset = lseek(mdstat_fd, 0L, 0);
+ if (offset == (off_t)-1) {
+ mdstat_close();
+ return NULL;
+ }
fd = dup(mdstat_fd);
if (fd >= 0)
f = fdopen(fd, "r");
--
1.8.3.1
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