From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lukasz Dorau Subject: [PATCH] fix: correct unlocking of map file Date: Thu, 29 Sep 2011 09:55:20 +0200 Message-ID: <20110929075520.5470.28705.stgit@gklab-128-085.igk.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Return-path: Sender: linux-raid-owner@vger.kernel.org To: neilb@suse.de Cc: linux-raid@vger.kernel.org, marcin.labun@intel.com, ed.ciechanowski@intel.com List-Id: linux-raid.ids 1. Three missing map_unlock() calls were added. 2. Map file's lock must be released by an explicit LOCK_UN operation, because duplicated (e.g. created by fork()) descriptors inherit the lock. As a result child process which inherits open descriptors with lock can block another process of mdadm. Signed-off-by: Lukasz Dorau --- Incremental.c | 3 +++ mapfile.c | 4 ++++ 2 files changed, 7 insertions(+), 0 deletions(-) diff --git a/Incremental.c b/Incremental.c index 571d45d..b90089b 100644 --- a/Incremental.c +++ b/Incremental.c @@ -1472,6 +1472,7 @@ static int Incremental_container(struct supertype *st, char *devname, "Cannot activate array(s).\n"); /* free container data and exit */ sysfs_free(list); + map_unlock(&map); return 2; } @@ -1535,6 +1536,7 @@ static int Incremental_container(struct supertype *st, char *devname, fprintf(stderr, Name ": array %s/%s is " "explicitly ignored by mdadm.conf\n", match->container, match->member); + map_unlock(&map); return 2; } if (match) @@ -1550,6 +1552,7 @@ static int Incremental_container(struct supertype *st, char *devname, if (mdfd < 0) { fprintf(stderr, Name ": failed to open %s: %s.\n", chosen_name, strerror(errno)); + map_unlock(&map); return 2; } diff --git a/mapfile.c b/mapfile.c index ff1e973..98c0780 100644 --- a/mapfile.c +++ b/mapfile.c @@ -149,6 +149,10 @@ int map_lock(struct map_ent **melp) void map_unlock(struct map_ent **melp) { if (lf) { + /* lock must be released by an explicit LOCK_UN operation + * because duplicated descriptors inherit the lock + */ + flock(fileno(lf), LOCK_UN); /* must unlink before closing the file, * as only the owner of the lock may * unlink the file