[PATCH] fix: correct unlocking of map file
flat view
STALE5484d
From: Lukasz Dorau <hidden>
Date: 2011-09-29 07:55:20
Subsystem:
the rest · Maintainer:
Linus Torvalds
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 <redacted> --- 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