udev: Move udev_block() and udev_unblock() into udev.c

Add kernel style comments and better error handling.

Signed-off-by: Mateusz Grzonka <[email protected]>
Signed-off-by: Kinga Tanska <[email protected]>
Signed-off-by: Jes Sorensen <[email protected]>

Create.c

@@ -23,6 +23,7 @@
  */
 
 #include	"mdadm.h"
+#include	"udev.h"
 #include	"md_u.h"
 #include	"md_p.h"
 #include	<ctype.h>

lib.c

@@ -204,35 +204,6 @@ char *fd2devnm(int fd)
 	return NULL;
 }
 
-/* When we create a new array, we don't want the content to
- * be immediately examined by udev - it is probably meaningless.
- * So create /run/mdadm/creating-mdXXX and expect that a udev
- * rule will noticed this and act accordingly.
- */
-static char block_path[] = "/run/mdadm/creating-%s";
-static char *unblock_path = NULL;
-void udev_block(char *devnm)
-{
-	int fd;
-	char *path = NULL;
-
-	xasprintf(&path, block_path, devnm);
-	fd = open(path, O_CREAT|O_RDWR, 0600);
-	if (fd >= 0) {
-		close(fd);
-		unblock_path = path;
-	} else
-		free(path);
-}
-
-void udev_unblock(void)
-{
-	if (unblock_path)
-		unlink(unblock_path);
-	free(unblock_path);
-	unblock_path = NULL;
-}
-
 /*
  * convert a major/minor pair for a block device into a name in /dev, if possible.
  * On the first call, walk /dev collecting name.

mdadm.h

@@ -1765,8 +1765,6 @@ extern char *fd2kname(int fd);
 extern char *stat2devnm(struct stat *st);
 bool stat_is_md_dev(struct stat *st);
 extern char *fd2devnm(int fd);
-extern void udev_block(char *devnm);
-extern void udev_unblock(void);
 
 extern int in_initrd(void);
 

mdopen.c

@@ -336,17 +336,17 @@ int create_mddev(char *dev, char *name, int autof, int trustworthy,
 	devnm[0] = 0;
 	if (num < 0 && cname && ci->names) {
 		sprintf(devnm, "md_%s", cname);
-		if (block_udev)
-			udev_block(devnm);
+		if (block_udev && udev_block(devnm) != UDEV_STATUS_SUCCESS)
+			return -1;
 		if (!create_named_array(devnm)) {
 			devnm[0] = 0;
 			udev_unblock();
 		}
 	}
 	if (num >= 0) {
 		sprintf(devnm, "md%d", num);
-		if (block_udev)
-			udev_block(devnm);
+		if (block_udev && udev_block(devnm) != UDEV_STATUS_SUCCESS)
+			return -1;
 		if (!create_named_array(devnm)) {
 			devnm[0] = 0;
 			udev_unblock();
@@ -369,8 +369,8 @@ int create_mddev(char *dev, char *name, int autof, int trustworthy,
 				return -1;
 			}
 		}
-		if (block_udev)
-			udev_block(devnm);
+		if (block_udev && udev_block(devnm) != UDEV_STATUS_SUCCESS)
+			return -1;
 		create_named_array(devnm);
 	}
 

udev.c

@@ -28,6 +28,8 @@
 #include	<syslog.h>
 #include	<libudev.h>
 
+static char *unblock_path;
+
 /*
  * udev_is_available() - Checks for udev in the system.
  *
@@ -148,3 +150,45 @@ enum udev_status udev_wait_for_events(int seconds)
 	return UDEV_STATUS_TIMEOUT;
 }
 #endif
+
+/*
+ * udev_block() - Block udev from examining newly created arrays.
+ *
+ * When array is created, we don't want udev to examine it immediately.
+ * Function creates /run/mdadm/creating-mdXXX and expects that udev rule
+ * will notice it and act accordingly.
+ *
+ * Return:
+ * UDEV_STATUS_SUCCESS when successfully blocked udev
+ * UDEV_STATUS_ERROR on error
+ */
+enum udev_status udev_block(char *devnm)
+{
+	int fd;
+	char *path = xcalloc(1, BUFSIZ);
+
+	snprintf(path, BUFSIZ, "/run/mdadm/creating-%s", devnm);
+
+	fd = open(path, O_CREAT | O_RDWR, 0600);
+	if (!is_fd_valid(fd)) {
+		pr_err("Cannot block udev, error creating blocking file.\n");
+		pr_err("%s: %s\n", strerror(errno), path);
+		free(path);
+		return UDEV_STATUS_ERROR;
+	}
+
+	close(fd);
+	unblock_path = path;
+	return UDEV_STATUS_SUCCESS;
+}
+
+/*
+ * udev_unblock() - Unblock udev.
+ */
+void udev_unblock(void)
+{
+	if (unblock_path)
+		unlink(unblock_path);
+	free(unblock_path);
+	unblock_path = NULL;
+}

udev.h

@@ -34,4 +34,7 @@ bool udev_is_available(void);
 enum udev_status udev_wait_for_events(int seconds);
 #endif
 
+enum udev_status udev_block(char *devnm);
+void udev_unblock(void);
+
 #endif