From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tomasz Majchrzak Subject: [PATCH] Monitor: release /proc/mdstat fd when no arrays present Date: Tue, 5 Jul 2016 09:12:51 +0200 Message-ID: <1467702771-1375-1-git-send-email-tomasz.majchrzak@intel.com> Return-path: Sender: linux-raid-owner@vger.kernel.org To: linux-raid@vger.kernel.org Cc: Jes.Sorensen@redhat.com, aleksey.obitotskiy@intel.com, pawel.baldysiak@intel.com, artur.paszkiewicz@intel.com List-Id: linux-raid.ids 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 Reviewed-by: Artur Paszkiewicz --- 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