lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  linux-cve-announce  PHC 
Open Source and information security mailing list archives
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <20250721171557.34587-7-yukuai@kernel.org>
Date: Tue, 22 Jul 2025 01:15:52 +0800
From: Yu Kuai <yukuai@...nel.org>
To: corbet@....net,
	agk@...hat.co,
	snitzer@...nel.org,
	mpatocka@...hat.com,
	hch@....de,
	song@...nel.org,
	hare@...e.de
Cc: linux-doc@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	dm-devel@...ts.linux.dev,
	linux-raid@...r.kernel.org,
	yukuai3@...wei.com,
	yangerkun@...wei.com,
	yi.zhang@...wei.com,
	johnny.chenyi@...wei.com
Subject: [PATCH v4 06/11] md/md-bitmap: delay registration of bitmap_ops until creating bitmap

From: Yu Kuai <yukuai3@...wei.com>

Currently bitmap_ops is registered while allocating mddev, this is fine
when there is only one bitmap_ops.

Delay setting bitmap_ops until creating bitmap, so that user can choose
which bitmap to use before running the array.

Signed-off-by: Yu Kuai <yukuai3@...wei.com>
---
 Documentation/admin-guide/md.rst |  3 ++
 drivers/md/md.c                  | 81 ++++++++++++++++++++------------
 2 files changed, 55 insertions(+), 29 deletions(-)

diff --git a/Documentation/admin-guide/md.rst b/Documentation/admin-guide/md.rst
index 356d2a344f08..001363f81850 100644
--- a/Documentation/admin-guide/md.rst
+++ b/Documentation/admin-guide/md.rst
@@ -388,6 +388,9 @@ All md devices contain:
      bitmap
          The default internal bitmap
 
+If bitmap_type is not none, then additional bitmap attributes bitmap/xxx or
+llbitmap/xxx will be created after md device KOBJ_CHANGE event.
+
 If bitmap_type is bitmap, then the md device will also contain:
 
   bitmap/location
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 41da352ccbde..744cac10506b 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -671,9 +671,11 @@ static void no_op(struct percpu_ref *r) {}
 
 static bool mddev_set_bitmap_ops(struct mddev *mddev)
 {
+	struct bitmap_operations *old = mddev->bitmap_ops;
 	struct md_submodule_head *head;
 
-	if (mddev->bitmap_id == ID_BITMAP_NONE)
+	if (mddev->bitmap_id == ID_BITMAP_NONE ||
+	    (old && old->head.id == mddev->bitmap_id))
 		return true;
 
 	xa_lock(&md_submodule);
@@ -691,6 +693,18 @@ static bool mddev_set_bitmap_ops(struct mddev *mddev)
 
 	mddev->bitmap_ops = (void *)head;
 	xa_unlock(&md_submodule);
+
+	if (mddev->bitmap_ops->group) {
+		if (sysfs_create_group(&mddev->kobj, mddev->bitmap_ops->group))
+			pr_warn("md: cannot register extra bitmap attributes for %s\n",
+				mdname(mddev));
+		else
+			/*
+			 * Inform user with KOBJ_CHANGE about new bitmap
+			 * attributes.
+			 */
+			kobject_uevent(&mddev->kobj, KOBJ_CHANGE);
+	}
 	return true;
 
 err:
@@ -700,28 +714,25 @@ static bool mddev_set_bitmap_ops(struct mddev *mddev)
 
 static void mddev_clear_bitmap_ops(struct mddev *mddev)
 {
+	if (mddev->bitmap_ops && mddev->bitmap_ops->group)
+		sysfs_remove_group(&mddev->kobj, mddev->bitmap_ops->group);
+
 	mddev->bitmap_ops = NULL;
 }
 
 int mddev_init(struct mddev *mddev)
 {
-	if (!IS_ENABLED(CONFIG_MD_BITMAP)) {
+	if (!IS_ENABLED(CONFIG_MD_BITMAP))
 		mddev->bitmap_id = ID_BITMAP_NONE;
-	} else {
+	else
 		mddev->bitmap_id = ID_BITMAP;
-		if (!mddev_set_bitmap_ops(mddev))
-			return -EINVAL;
-	}
 
 	if (percpu_ref_init(&mddev->active_io, active_io_release,
-			    PERCPU_REF_ALLOW_REINIT, GFP_KERNEL)) {
-		mddev_clear_bitmap_ops(mddev);
+			    PERCPU_REF_ALLOW_REINIT, GFP_KERNEL))
 		return -ENOMEM;
-	}
 
 	if (percpu_ref_init(&mddev->writes_pending, no_op,
 			    PERCPU_REF_ALLOW_REINIT, GFP_KERNEL)) {
-		mddev_clear_bitmap_ops(mddev);
 		percpu_ref_exit(&mddev->active_io);
 		return -ENOMEM;
 	}
@@ -759,7 +770,6 @@ EXPORT_SYMBOL_GPL(mddev_init);
 
 void mddev_destroy(struct mddev *mddev)
 {
-	mddev_clear_bitmap_ops(mddev);
 	percpu_ref_exit(&mddev->active_io);
 	percpu_ref_exit(&mddev->writes_pending);
 }
@@ -6137,11 +6147,6 @@ struct mddev *md_alloc(dev_t dev, char *name)
 		return ERR_PTR(error);
 	}
 
-	if (md_bitmap_registered(mddev) && mddev->bitmap_ops->group)
-		if (sysfs_create_group(&mddev->kobj, mddev->bitmap_ops->group))
-			pr_warn("md: cannot register extra bitmap attributes for %s\n",
-				mdname(mddev));
-
 	kobject_uevent(&mddev->kobj, KOBJ_ADD);
 	mddev->sysfs_state = sysfs_get_dirent_safe(mddev->kobj.sd, "array_state");
 	mddev->sysfs_level = sysfs_get_dirent_safe(mddev->kobj.sd, "level");
@@ -6217,6 +6222,26 @@ static void md_safemode_timeout(struct timer_list *t)
 
 static int start_dirty_degraded;
 
+static int md_bitmap_create(struct mddev *mddev)
+{
+	if (mddev->bitmap_id == ID_BITMAP_NONE)
+		return -EINVAL;
+
+	if (!mddev_set_bitmap_ops(mddev))
+		return -ENOENT;
+
+	return mddev->bitmap_ops->create(mddev);
+}
+
+static void md_bitmap_destroy(struct mddev *mddev)
+{
+	if (!md_bitmap_registered(mddev))
+		return;
+
+	mddev->bitmap_ops->destroy(mddev);
+	mddev_clear_bitmap_ops(mddev);
+}
+
 int md_run(struct mddev *mddev)
 {
 	int err;
@@ -6381,9 +6406,9 @@ int md_run(struct mddev *mddev)
 			(unsigned long long)pers->size(mddev, 0, 0) / 2);
 		err = -EINVAL;
 	}
-	if (err == 0 && pers->sync_request && md_bitmap_registered(mddev) &&
+	if (err == 0 && pers->sync_request &&
 	    (mddev->bitmap_info.file || mddev->bitmap_info.offset)) {
-		err = mddev->bitmap_ops->create(mddev);
+		err = md_bitmap_create(mddev);
 		if (err)
 			pr_warn("%s: failed to create bitmap (%d)\n",
 				mdname(mddev), err);
@@ -6456,8 +6481,7 @@ int md_run(struct mddev *mddev)
 		pers->free(mddev, mddev->private);
 	mddev->private = NULL;
 	put_pers(pers);
-	if (md_bitmap_registered(mddev))
-		mddev->bitmap_ops->destroy(mddev);
+	md_bitmap_destroy(mddev);
 abort:
 	bioset_exit(&mddev->io_clone_set);
 exit_sync_set:
@@ -6480,7 +6504,7 @@ int do_md_run(struct mddev *mddev)
 	if (md_bitmap_registered(mddev)) {
 		err = mddev->bitmap_ops->load(mddev);
 		if (err) {
-			mddev->bitmap_ops->destroy(mddev);
+			md_bitmap_destroy(mddev);
 			goto out;
 		}
 	}
@@ -6666,8 +6690,7 @@ static void __md_stop(struct mddev *mddev)
 {
 	struct md_personality *pers = mddev->pers;
 
-	if (md_bitmap_registered(mddev))
-		mddev->bitmap_ops->destroy(mddev);
+	md_bitmap_destroy(mddev);
 	mddev_detach(mddev);
 	spin_lock(&mddev->lock);
 	mddev->pers = NULL;
@@ -7443,16 +7466,16 @@ static int set_bitmap_file(struct mddev *mddev, int fd)
 	err = 0;
 	if (mddev->pers) {
 		if (fd >= 0) {
-			err = mddev->bitmap_ops->create(mddev);
+			err = md_bitmap_create(mddev);
 			if (!err)
 				err = mddev->bitmap_ops->load(mddev);
 
 			if (err) {
-				mddev->bitmap_ops->destroy(mddev);
+				md_bitmap_destroy(mddev);
 				fd = -1;
 			}
 		} else if (fd < 0) {
-			mddev->bitmap_ops->destroy(mddev);
+			md_bitmap_destroy(mddev);
 		}
 	}
 
@@ -7767,12 +7790,12 @@ static int update_array_info(struct mddev *mddev, mdu_array_info_t *info)
 				mddev->bitmap_info.default_offset;
 			mddev->bitmap_info.space =
 				mddev->bitmap_info.default_space;
-			rv = mddev->bitmap_ops->create(mddev);
+			rv = md_bitmap_create(mddev);
 			if (!rv)
 				rv = mddev->bitmap_ops->load(mddev);
 
 			if (rv)
-				mddev->bitmap_ops->destroy(mddev);
+				md_bitmap_destroy(mddev);
 		} else {
 			struct md_bitmap_stats stats;
 
@@ -7798,7 +7821,7 @@ static int update_array_info(struct mddev *mddev, mdu_array_info_t *info)
 				put_cluster_ops(mddev);
 				mddev->safemode_delay = DEFAULT_SAFEMODE_DELAY;
 			}
-			mddev->bitmap_ops->destroy(mddev);
+			md_bitmap_destroy(mddev);
 			mddev->bitmap_info.offset = 0;
 		}
 	}
-- 
2.43.0


Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ