From f71d2b8f4bd50888d1e20e9fdf7af9beb0729aae Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Mon, 5 Dec 2016 17:27:03 +1100 Subject: [PATCH] mdopen: open md devices O_RDONLY There is no need to request write access when opening the md device, as we never write to it, and none of the ioctls we use require write access. If we do open with write access, then when we close, udev notices that the device was closed after being open for write access, and it generates a CHANGE event. This is generally unwanted, and particularly problematic when mdadm is trying to --stop the array, as the CHANGE event can cause the array to be re-opened before it completely closed, which results in a new mddev being allocated. So just use O_RDONLY instead of O_RDWR. Reported-by: Marc Smith Signed-off-by: NeilBrown Signed-off-by: Jes Sorensen --- mdassemble.c | 2 +- mdopen.c | 4 +--- 2 files changed, 2 insertions(+), 4 deletions(-) diff --git a/mdassemble.c b/mdassemble.c index 78d363a..471ffeb 100644 --- a/mdassemble.c +++ b/mdassemble.c @@ -32,7 +32,7 @@ char const Name[] = "mdassemble"; /* from mdopen.c */ int open_mddev(char *dev, int report_errors/*unused*/) { - int mdfd = open(dev, O_RDWR); + int mdfd = open(dev, O_RDONLY); if (mdfd < 0) pr_err("error opening %s: %s\n", dev, strerror(errno)); diff --git a/mdopen.c b/mdopen.c index 0ea3874..685ca32 100644 --- a/mdopen.c +++ b/mdopen.c @@ -416,9 +416,7 @@ int create_mddev(char *dev, char *name, int autof, int trustworthy, */ int open_mddev(char *dev, int report_errors) { - int mdfd = open(dev, O_RDWR); - if (mdfd < 0 && errno == EACCES) - mdfd = open(dev, O_RDONLY); + int mdfd = open(dev, O_RDONLY); if (mdfd < 0) { if (report_errors) pr_err("error opening %s: %s\n",