File 0011-Safeguard-against-writing-to-an-active-dev... of Package mdadm

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File 0011-Safeguard-against-writing-to-an-active-device-of-ano.patch of Package mdadm (Revision 1bc6a8896eed87a2d0f82cddc41e0446)

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From 84271df881095f261007bd8ba518787532b6cbe5 Mon Sep 17 00:00:00 2001
From: Guoqing Jiang <gqjiang@suse.com>
Date: Thu, 2 Jul 2015 15:11:43 +0800
Subject: [PATCH 11/11] Safeguard against writing to an active device of
 another node

Modifying an exiting device's superblock or creating a new superblock
on an existing device needs to be checked because the device could be
in use by another node in another array. So, we check this by taking
all superblock locks in userspace so that we don't  step onto an active
device used by another node and safeguard against accidental edits.
After the edit is complete, we release all locks and the lockspace so
that it can be used by the kernel space.

Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: Guoqing Jiang <gqjiang@suse.com>
---
 Makefile |   6 ++-
 mdadm.h  |   3 ++
 super1.c |  62 +++++++++++++++++++++++++++++++
 util.c   | 127 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 197 insertions(+), 1 deletion(-)

diff --git a/Makefile b/Makefile
index e3b6529..2ff50cb 100644
--- a/Makefile
+++ b/Makefile
@@ -81,11 +81,12 @@ FAILED_SLOTS_DIR = $(RUN_DIR)/failed-slots
 SYSTEMD_DIR=/lib/systemd/system
 
 COROSYNC:=$(shell [ -d /usr/include/corosync ] || echo -DNO_COROSYNC)
+DLM:=$(shell [ -f /usr/include/libdlm.h ] || echo -DNO_DLM)
 
 DIRFLAGS = -DMAP_DIR=\"$(MAP_DIR)\" -DMAP_FILE=\"$(MAP_FILE)\"
 DIRFLAGS += -DMDMON_DIR=\"$(MDMON_DIR)\"
 DIRFLAGS += -DFAILED_SLOTS_DIR=\"$(FAILED_SLOTS_DIR)\"
-CFLAGS = $(CWFLAGS) $(CXFLAGS) -DSendmail=\""$(MAILCMD)"\" $(CONFFILEFLAGS) $(DIRFLAGS) $(COROSYNC)
+CFLAGS = $(CWFLAGS) $(CXFLAGS) -DSendmail=\""$(MAILCMD)"\" $(CONFFILEFLAGS) $(DIRFLAGS) $(COROSYNC) $(DLM)
 
 VERSION = $(shell [ -d .git ] && git describe HEAD | sed 's/mdadm-//')
 VERS_DATE = $(shell [ -d .git ] && date --date="`git log -n1 --format=format:%cd --date=short`" '+%0dth %B %Y' | sed -e 's/1th/1st/' -e 's/2th/2nd/' -e 's/11st/11th/' -e 's/12nd/12th/')
@@ -105,6 +106,9 @@ endif
 # LDFLAGS = -static
 # STRIP = -s
 LDLIBS=-ldl
+ifneq ($(DLM), -DNO_DLM)
+LDLIBS += -ldlm_lt
+endif
 
 INSTALL = /usr/bin/install
 DESTDIR =
diff --git a/mdadm.h b/mdadm.h
index c1216fa..b046d36 100644
--- a/mdadm.h
+++ b/mdadm.h
@@ -1429,6 +1429,9 @@ extern char *fd2devnm(int fd);
 
 extern int in_initrd(void);
 extern int get_cluster_name(char **name);
+extern int is_clustered(struct supertype *st);
+extern int cluster_get_dlmlock(struct supertype *st, int *lockid);
+extern int cluster_release_dlmlock(struct supertype *st, int lockid);
 
 #define _ROUND_UP(val, base)	(((val) + (base) - 1) & ~(base - 1))
 #define ROUND_UP(val, base)	_ROUND_UP(val, (typeof(val))(base))
diff --git a/super1.c b/super1.c
index 26df83d..44166c3 100644
--- a/super1.c
+++ b/super1.c
@@ -1081,6 +1081,18 @@ static int update_super1(struct supertype *st, struct mdinfo *info,
 	int rv = 0;
 	struct mdp_superblock_1 *sb = st->sb;
 
+#ifndef NO_DLM
+	int lockid;
+	if (is_clustered(st)) {
+		rv = cluster_get_dlmlock(st, &lockid);
+		if (rv) {
+			pr_err("Cannot get dlmlock in %s return %d\n", __func__, rv);
+			cluster_release_dlmlock(st, lockid);
+			return rv;
+		}
+	}
+#endif
+
 	if (strcmp(update, "homehost") == 0 &&
 	    homehost) {
 		/* Note that 'homehost' is special as it is really
@@ -1345,6 +1357,10 @@ static int update_super1(struct supertype *st, struct mdinfo *info,
 		rv = -1;
 
 	sb->sb_csum = calc_sb_1_csum(sb);
+#ifndef NO_DLM
+	if (is_clustered(st))
+		cluster_release_dlmlock(st, lockid);
+#endif
 	return rv;
 }
 
@@ -1449,6 +1465,17 @@ static int add_to_super1(struct supertype *st, mdu_disk_info_t *dk,
 	__u16 *rp = sb->dev_roles + dk->number;
 	struct devinfo *di, **dip;
 
+#ifndef NO_DLM
+	int rv, lockid;
+	if (is_clustered(st)) {
+		rv = cluster_get_dlmlock(st, &lockid);
+		if (rv) {
+			pr_err("Cannot get dlmlock in %s return %d\n", __func__, rv);
+			cluster_release_dlmlock(st, lockid);
+			return rv;
+		}
+	}
+#endif
 	if ((dk->state & 6) == 6) /* active, sync */
 		*rp = __cpu_to_le16(dk->raid_disk);
 	else if ((dk->state & ~2) == 0) /* active or idle -> spare */
@@ -1475,6 +1502,10 @@ static int add_to_super1(struct supertype *st, mdu_disk_info_t *dk,
 	di->next = NULL;
 	*dip = di;
 
+#ifndef NO_DLM
+	if (is_clustered(st))
+		cluster_release_dlmlock(st, lockid);
+#endif
 	return 0;
 }
 #endif
@@ -1489,6 +1520,18 @@ static int store_super1(struct supertype *st, int fd)
 	int sbsize;
 	unsigned long long dsize;
 
+#ifndef NO_DLM
+	int rv, lockid;
+	if (is_clustered(st)) {
+		rv = cluster_get_dlmlock(st, &lockid);
+		if (rv) {
+			pr_err("Cannot get dlmlock in %s return %d\n", __func__, rv);
+			cluster_release_dlmlock(st, lockid);
+			return rv;
+		}
+	}
+#endif
+
 	if (!get_dev_size(fd, NULL, &dsize))
 		return 1;
 
@@ -1548,6 +1591,10 @@ static int store_super1(struct supertype *st, int fd)
 		}
 	}
 	fsync(fd);
+#ifndef NO_DLM
+	if (is_clustered(st))
+		cluster_release_dlmlock(st, lockid);
+#endif
 	return 0;
 }
 
@@ -2295,6 +2342,17 @@ static int write_bitmap1(struct supertype *st, int fd, enum bitmap_update update
 
 static void free_super1(struct supertype *st)
 {
+#ifndef NO_DLM
+	int rv, lockid;
+	if (is_clustered(st)) {
+		rv = cluster_get_dlmlock(st, &lockid);
+		if (rv) {
+			pr_err("Cannot get dlmlock in %s return %d\n", __func__, rv);
+			cluster_release_dlmlock(st, lockid);
+			return;
+		}
+	}
+#endif
 	if (st->sb)
 		free(st->sb);
 	while (st->info) {
@@ -2305,6 +2363,10 @@ static void free_super1(struct supertype *st)
 		free(di);
 	}
 	st->sb = NULL;
+#ifndef NO_DLM
+	if (is_clustered(st))
+		cluster_release_dlmlock(st, lockid);
+#endif
 }
 
 #ifndef MDASSEMBLE
diff --git a/util.c b/util.c
index 70d45dd..8fdb468 100644
--- a/util.c
+++ b/util.c
@@ -24,6 +24,7 @@
 
 #include	"mdadm.h"
 #include	"md_p.h"
+#include	<sys/poll.h>
 #include	<sys/socket.h>
 #include	<sys/utsname.h>
 #include	<sys/wait.h>
@@ -42,6 +43,10 @@
 #else
  #include	<corosync/cmap.h>
 #endif
+#ifndef NO_DLM
+#include	<libdlm.h>
+#include	<errno.h>
+#endif
 
 
 /*
@@ -88,6 +93,128 @@ struct blkpg_partition {
    aren't permitted). */
 #define BUILD_BUG_ON_ZERO(e) (sizeof(struct { int:-!!(e); }))
 
+#ifndef NO_DLM
+struct dlm_lock_resource {
+	dlm_lshandle_t *ls;
+	struct dlm_lksb lksb;
+};
+
+struct dlm_lock_resource *dlm_lock_res = NULL;
+static int ast_called = 0;
+
+int is_clustered(struct supertype *st)
+{
+	/* is it a cluster md or not */
+	return st->cluster_name ? 1 :0;
+}
+
+/* Using poll(2) to wait for and dispatch ASTs */
+static int poll_for_ast(dlm_lshandle_t ls)
+{
+	struct pollfd pfd;
+
+	pfd.fd = dlm_ls_get_fd(ls);
+	pfd.events = POLLIN;
+
+	while (!ast_called)
+	{
+		if (poll(&pfd, 1, 0) < 0)
+		{
+			perror("poll");
+			return -1;
+		}
+		dlm_dispatch(dlm_ls_get_fd(ls));
+	}
+	ast_called = 0;
+
+	return 0;
+}
+
+static void dlm_ast(void *arg)
+{
+	ast_called = 1;
+}
+
+/* Create the lockspace, take bitmapXXX locks on all the bitmaps. */
+int cluster_get_dlmlock(struct supertype *st, int *lockid)
+{
+	int ret;
+	char str[64];
+	int flags = LKF_NOQUEUE;
+
+	dlm_lock_res = xmalloc(sizeof(struct dlm_lock_resource));
+	if (!dlm_lock_res)
+		return -ENOMEM;
+
+	dlm_lock_res->ls = dlm_create_lockspace(st->cluster_name, O_RDWR);
+	if (!dlm_lock_res->ls) {
+		pr_err("%s failed to create lockspace\n", st->cluster_name);
+		return -1;
+	}
+
+	/* Conversions need the lockid in the LKSB */
+	if (flags & LKF_CONVERT)
+		dlm_lock_res->lksb.sb_lkid = *lockid;
+
+	snprintf(str, 64, "bitmap%04d", st->nodes);
+	/* if flags with LKF_CONVERT causes below return ENOENT which means
+	 * "No such file or directory" */
+	ret = dlm_ls_lock(dlm_lock_res->ls, LKM_PWMODE, &dlm_lock_res->lksb,
+			  flags, str, strlen(str), 0, dlm_ast,
+			  dlm_lock_res, NULL, NULL);
+	if (ret) {
+		pr_err("error %d when get PW mode on lock %s\n", errno, str);
+		return ret;
+	}
+
+	/* Wait for it to complete */
+	poll_for_ast(dlm_lock_res->ls);
+	*lockid = dlm_lock_res->lksb.sb_lkid;
+
+	errno =	dlm_lock_res->lksb.sb_status;
+	if (errno) {
+	    pr_err("error %d happened in ast with lock %s\n", errno, str);
+	    return -1;
+	}
+
+	return 0;
+}
+
+int cluster_release_dlmlock(struct supertype *st, int lockid)
+{
+	int ret;
+
+	/* if flags with LKF_CONVERT causes below return EINVAL which means
+	 * "Invalid argument" */
+	ret = dlm_ls_unlock(dlm_lock_res->ls, lockid, 0, &dlm_lock_res->lksb, dlm_lock_res);
+	if (ret) {
+		pr_err("error %d happened when unlock\n", errno);
+		/* XXX make sure the lock is unlocked eventually */
+		return ret;
+	}
+
+	/* Wait for it to complete */
+	poll_for_ast(dlm_lock_res->ls);
+
+	errno =	dlm_lock_res->lksb.sb_status;
+	if (errno != EUNLOCK) {
+		pr_err("error %d happened in ast when unlock lockspace\n", errno);
+		/* XXX make sure the lockspace is unlocked eventually */
+		return -1;
+	}
+
+	ret = dlm_release_lockspace(st->cluster_name, dlm_lock_res->ls, 1);
+	if (ret) {
+		pr_err("error %d happened when release lockspace\n", errno);
+		/* XXX make sure the lockspace is released eventually */
+		return ret;
+	}
+	free(dlm_lock_res);
+
+	return 0;
+}
+#endif
+
 /*
  * Parse a 128 bit uuid in 4 integers
  * format is 32 hexx nibbles with options :.<space> separator
-- 
1.7.12.4

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