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Message-ID: <20250721171557.34587-6-yukuai@kernel.org>
Date: Tue, 22 Jul 2025 01:15:51 +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 05/11] md/md-bitmap: add a new sysfs api bitmap_type
From: Yu Kuai <yukuai3@...wei.com>
The api will be used by mdadm to set bitmap_type while creating new array
or assembling array, prepare to add a new bitmap.
Currently available options are:
cat /sys/block/md0/md/bitmap_type
none [bitmap]
Signed-off-by: Yu Kuai <yukuai3@...wei.com>
Reviewed-by: Hannes Reinecke <hare@...e.de>
---
Documentation/admin-guide/md.rst | 73 ++++++++++++++++------------
drivers/md/md.c | 81 ++++++++++++++++++++++++++++++++
2 files changed, 124 insertions(+), 30 deletions(-)
diff --git a/Documentation/admin-guide/md.rst b/Documentation/admin-guide/md.rst
index 4ff2cc291d18..356d2a344f08 100644
--- a/Documentation/admin-guide/md.rst
+++ b/Documentation/admin-guide/md.rst
@@ -347,6 +347,49 @@ All md devices contain:
active-idle
like active, but no writes have been seen for a while (safe_mode_delay).
+ consistency_policy
+ This indicates how the array maintains consistency in case of unexpected
+ shutdown. It can be:
+
+ none
+ Array has no redundancy information, e.g. raid0, linear.
+
+ resync
+ Full resync is performed and all redundancy is regenerated when the
+ array is started after unclean shutdown.
+
+ bitmap
+ Resync assisted by a write-intent bitmap.
+
+ journal
+ For raid4/5/6, journal device is used to log transactions and replay
+ after unclean shutdown.
+
+ ppl
+ For raid5 only, Partial Parity Log is used to close the write hole and
+ eliminate resync.
+
+ The accepted values when writing to this file are ``ppl`` and ``resync``,
+ used to enable and disable PPL.
+
+ uuid
+ This indicates the UUID of the array in the following format:
+ xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
+
+ bitmap_type
+ [RW] When read, this file will display the current and available
+ bitmap for this array. The currently active bitmap will be enclosed
+ in [] brackets. Writing an bitmap name or ID to this file will switch
+ control of this array to that new bitmap. Note that writing a new
+ bitmap for created array is forbidden.
+
+ none
+ No bitmap
+ bitmap
+ The default internal bitmap
+
+If bitmap_type is bitmap, then the md device will also contain:
+
bitmap/location
This indicates where the write-intent bitmap for the array is
stored.
@@ -401,36 +444,6 @@ All md devices contain:
once the array becomes non-degraded, and this fact has been
recorded in the metadata.
- consistency_policy
- This indicates how the array maintains consistency in case of unexpected
- shutdown. It can be:
-
- none
- Array has no redundancy information, e.g. raid0, linear.
-
- resync
- Full resync is performed and all redundancy is regenerated when the
- array is started after unclean shutdown.
-
- bitmap
- Resync assisted by a write-intent bitmap.
-
- journal
- For raid4/5/6, journal device is used to log transactions and replay
- after unclean shutdown.
-
- ppl
- For raid5 only, Partial Parity Log is used to close the write hole and
- eliminate resync.
-
- The accepted values when writing to this file are ``ppl`` and ``resync``,
- used to enable and disable PPL.
-
- uuid
- This indicates the UUID of the array in the following format:
- xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
-
-
As component devices are added to an md array, they appear in the ``md``
directory as new directories named::
diff --git a/drivers/md/md.c b/drivers/md/md.c
index c0499bd8a2aa..41da352ccbde 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -4197,6 +4197,86 @@ new_level_store(struct mddev *mddev, const char *buf, size_t len)
static struct md_sysfs_entry md_new_level =
__ATTR(new_level, 0664, new_level_show, new_level_store);
+static ssize_t
+bitmap_type_show(struct mddev *mddev, char *page)
+{
+ struct md_submodule_head *head;
+ unsigned long i;
+ ssize_t len = 0;
+
+ if (mddev->bitmap_id == ID_BITMAP_NONE)
+ len += sprintf(page + len, "[none] ");
+ else
+ len += sprintf(page + len, "none ");
+
+ xa_lock(&md_submodule);
+ xa_for_each(&md_submodule, i, head) {
+ if (head->type != MD_BITMAP)
+ continue;
+
+ if (mddev->bitmap_id == head->id)
+ len += sprintf(page + len, "[%s] ", head->name);
+ else
+ len += sprintf(page + len, "%s ", head->name);
+ }
+ xa_unlock(&md_submodule);
+
+ len += sprintf(page + len, "\n");
+ return len;
+}
+
+static ssize_t
+bitmap_type_store(struct mddev *mddev, const char *buf, size_t len)
+{
+ struct md_submodule_head *head;
+ enum md_submodule_id id;
+ unsigned long i;
+ int err = 0;
+
+ xa_lock(&md_submodule);
+
+ if (mddev->bitmap_ops) {
+ err = -EBUSY;
+ goto out;
+ }
+
+ if (cmd_match(buf, "none")) {
+ mddev->bitmap_id = ID_BITMAP_NONE;
+ goto out;
+ }
+
+ xa_for_each(&md_submodule, i, head) {
+ if (head->type == MD_BITMAP && cmd_match(buf, head->name)) {
+ mddev->bitmap_id = head->id;
+ goto out;
+ }
+ }
+
+ err = kstrtoint(buf, 10, &id);
+ if (err)
+ goto out;
+
+ if (id == ID_BITMAP_NONE) {
+ mddev->bitmap_id = id;
+ goto out;
+ }
+
+ head = xa_load(&md_submodule, id);
+ if (head && head->type == MD_BITMAP) {
+ mddev->bitmap_id = id;
+ goto out;
+ }
+
+ err = -ENOENT;
+
+out:
+ xa_unlock(&md_submodule);
+ return err ? err : len;
+}
+
+static struct md_sysfs_entry md_bitmap_type =
+__ATTR(bitmap_type, 0664, bitmap_type_show, bitmap_type_store);
+
static ssize_t
layout_show(struct mddev *mddev, char *page)
{
@@ -5761,6 +5841,7 @@ __ATTR(serialize_policy, S_IRUGO | S_IWUSR, serialize_policy_show,
static struct attribute *md_default_attrs[] = {
&md_level.attr,
&md_new_level.attr,
+ &md_bitmap_type.attr,
&md_layout.attr,
&md_raid_disks.attr,
&md_uuid.attr,
--
2.43.0
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