From: Su Yue <l@damenly.org>
To: Yu Kuai <yukuai@fnnas.com>
Cc: Song Liu <song@kernel.org>,
glass.su@suse.com, Li Nan <linan122@huawei.com>,
Xiao Ni <xiao@kernel.org>,
linux-raid@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v13 3/3] md/md-bitmap: add a none backend for bitmap grow
Date: Sat, 25 Apr 2026 16:39:30 +0800 [thread overview]
Message-ID: <8qab77st.fsf@damenly.org> (raw)
In-Reply-To: <20260425024615.1696892-4-yukuai@fnnas.com> (Yu Kuai's message of "Sat, 25 Apr 2026 10:46:15 +0800")
On Sat 25 Apr 2026 at 10:46, Yu Kuai <yukuai@fnnas.com> wrote:
> Add a real none bitmap backend that exposes the common bitmap
> sysfs
> group and use it to keep bitmap/location available when an array
> has no
> bitmap.
>
> Then switch the bitmap location sysfs path to move only between
> none
> and the classic bitmap backend, using the no-sysfs bitmap
> helpers while
> merging or unmerging the internal bitmap sysfs group.
>
> This restores mdadm --grow bitmap addition through
> bitmap/location.
>
> Signed-off-by: Yu Kuai <yukuai@fnnas.com>
>
Reviewed-by: Su Yue <glass.su@suse.com>
> ---
> drivers/md/md-bitmap.c | 108
> ++++++++++++++++++++++++++++++++++++++---
> drivers/md/md.c | 42 +++++++++++++---
> drivers/md/md.h | 3 ++
> 3 files changed, 137 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/md/md-bitmap.c b/drivers/md/md-bitmap.c
> index eba649703a1c..028b9ca8ce52 100644
> --- a/drivers/md/md-bitmap.c
> +++ b/drivers/md/md-bitmap.c
> @@ -216,6 +216,7 @@ struct bitmap {
> };
>
> static struct workqueue_struct *md_bitmap_wq;
> +static struct attribute_group md_bitmap_internal_group;
>
> static int __bitmap_resize(struct bitmap *bitmap, sector_t
> blocks,
> int chunksize, bool init);
> @@ -2580,6 +2581,30 @@ static int bitmap_resize(struct mddev
> *mddev, sector_t blocks, int chunksize)
> return __bitmap_resize(bitmap, blocks, chunksize, false);
> }
>
> +static bool bitmap_none_enabled(void *data, bool flush)
> +{
> + return false;
> +}
> +
> +static int bitmap_none_create(struct mddev *mddev)
> +{
> + return 0;
> +}
> +
> +static int bitmap_none_load(struct mddev *mddev)
> +{
> + return 0;
> +}
> +
> +static void bitmap_none_destroy(struct mddev *mddev)
> +{
> +}
> +
> +static int bitmap_none_get_stats(void *data, struct
> md_bitmap_stats *stats)
> +{
> + return -ENOENT;
> +}
> +
> static ssize_t
> location_show(struct mddev *mddev, char *page)
> {
> @@ -2618,7 +2643,11 @@ location_store(struct mddev *mddev, const
> char *buf, size_t len)
> goto out;
> }
>
> - bitmap_destroy(mddev);
> + sysfs_unmerge_group(&mddev->kobj,
> &md_bitmap_internal_group);
> + md_bitmap_destroy_nosysfs(mddev);
> + mddev->bitmap_id = ID_BITMAP_NONE;
> + if (!mddev_set_bitmap_ops_nosysfs(mddev))
> + goto none_err;
> mddev->bitmap_info.offset = 0;
> if (mddev->bitmap_info.file) {
> struct file *f = mddev->bitmap_info.file;
> @@ -2654,16 +2683,25 @@ location_store(struct mddev *mddev,
> const char *buf, size_t len)
> }
>
> mddev->bitmap_info.offset = offset;
> - rv = bitmap_create(mddev);
> + md_bitmap_destroy_nosysfs(mddev);
> + mddev->bitmap_id = ID_BITMAP;
> + if (!mddev_set_bitmap_ops_nosysfs(mddev))
> + goto bitmap_err;
> +
> + rv = md_bitmap_create_nosysfs(mddev);
> if (rv)
> - goto out;
> + goto create_err;
>
> - rv = bitmap_load(mddev);
> + rv = mddev->bitmap_ops->load(mddev);
> if (rv) {
> mddev->bitmap_info.offset = 0;
> - bitmap_destroy(mddev);
> - goto out;
> + goto load_err;
> }
> +
> + rv = sysfs_merge_group(&mddev->kobj,
> + &md_bitmap_internal_group);
> + if (rv)
> + goto merge_err;
> }
> }
> if (!mddev->external) {
> @@ -2679,6 +2717,22 @@ location_store(struct mddev *mddev, const
> char *buf, size_t len)
> if (rv)
> return rv;
> return len;
> +
> +merge_err:
> + mddev->bitmap_info.offset = 0;
> +load_err:
> + md_bitmap_destroy_nosysfs(mddev);
> +create_err:
> + mddev->bitmap_info.offset = 0;
> + mddev->bitmap_id = ID_BITMAP_NONE;
> + if (!mddev_set_bitmap_ops_nosysfs(mddev))
> + rv = -ENOENT;
> + goto out;
> +bitmap_err:
> + rv = -ENOENT;
> +none_err:
> + mddev->bitmap_info.offset = 0;
> + goto out;
> }
>
> static struct md_sysfs_entry bitmap_location =
> @@ -2987,6 +3041,27 @@ static const struct attribute_group
> *bitmap_groups[] = {
> NULL,
> };
>
> +static const struct attribute_group *bitmap_none_groups[] = {
> + &md_bitmap_common_group,
> + NULL,
> +};
> +
> +static struct bitmap_operations bitmap_none_ops = {
> + .head = {
> + .type = MD_BITMAP,
> + .id = ID_BITMAP_NONE,
> + .name = "none",
> + },
> +
> + .enabled = bitmap_none_enabled,
> + .create = bitmap_none_create,
> + .load = bitmap_none_load,
> + .destroy = bitmap_none_destroy,
> + .get_stats = bitmap_none_get_stats,
> +
> + .groups = bitmap_none_groups,
> +};
> +
> static struct bitmap_operations bitmap_ops = {
> .head = {
> .type = MD_BITMAP,
> @@ -3033,16 +3108,33 @@ static struct bitmap_operations
> bitmap_ops = {
>
> int md_bitmap_init(void)
> {
> + int err;
> +
> md_bitmap_wq = alloc_workqueue("md_bitmap", WQ_MEM_RECLAIM |
> WQ_UNBOUND,
> 0);
> if (!md_bitmap_wq)
> return -ENOMEM;
>
> - return register_md_submodule(&bitmap_ops.head);
> + err = register_md_submodule(&bitmap_none_ops.head);
> + if (err)
> + goto err_wq;
> +
> + err = register_md_submodule(&bitmap_ops.head);
> + if (err)
> + goto err_none;
> +
> + return 0;
> +
> +err_none:
> + unregister_md_submodule(&bitmap_none_ops.head);
> +err_wq:
> + destroy_workqueue(md_bitmap_wq);
> + return err;
> }
>
> void md_bitmap_exit(void)
> {
> - destroy_workqueue(md_bitmap_wq);
> unregister_md_submodule(&bitmap_ops.head);
> + unregister_md_submodule(&bitmap_none_ops.head);
> + destroy_workqueue(md_bitmap_wq);
> }
> diff --git a/drivers/md/md.c b/drivers/md/md.c
> index 0ef81d116191..7937b927d923 100644
> --- a/drivers/md/md.c
> +++ b/drivers/md/md.c
> @@ -705,7 +705,7 @@ static void md_bitmap_sysfs_del(struct mddev
> *mddev)
> sysfs_remove_group(&mddev->kobj,
> mddev->bitmap_ops->groups[0]);
> }
>
> -static bool mddev_set_bitmap_ops_nosysfs(struct mddev *mddev)
> +bool mddev_set_bitmap_ops_nosysfs(struct mddev *mddev)
> {
> struct md_submodule_head *head;
>
> @@ -4275,7 +4275,7 @@ bitmap_type_show(struct mddev *mddev, char
> *page)
>
> xa_lock(&md_submodule);
> xa_for_each(&md_submodule, i, head) {
> - if (head->type != MD_BITMAP)
> + if (head->type != MD_BITMAP || head->id == ID_BITMAP_NONE)
> continue;
>
> if (mddev->bitmap_id == head->id)
> @@ -6535,7 +6535,7 @@ static enum md_submodule_id
> md_bitmap_get_id_from_sb(struct mddev *mddev)
> return id;
> }
>
> -static int md_bitmap_create_nosysfs(struct mddev *mddev)
> +int md_bitmap_create_nosysfs(struct mddev *mddev)
> {
> enum md_submodule_id orig_id = mddev->bitmap_id;
> enum md_submodule_id sb_id;
> @@ -6544,8 +6544,10 @@ static int
> md_bitmap_create_nosysfs(struct mddev *mddev)
> if (mddev->bitmap_id == ID_BITMAP_NONE)
> return -EINVAL;
>
> - if (!mddev_set_bitmap_ops_nosysfs(mddev))
> + if (!mddev_set_bitmap_ops_nosysfs(mddev)) {
> + mddev->bitmap_id = orig_id;
> return -ENOENT;
> + }
>
> err = mddev->bitmap_ops->create(mddev);
> if (!err)
> @@ -6559,8 +6561,10 @@ static int
> md_bitmap_create_nosysfs(struct mddev *mddev)
> mddev->bitmap_ops = NULL;
>
> sb_id = md_bitmap_get_id_from_sb(mddev);
> - if (sb_id == ID_BITMAP_NONE || sb_id == orig_id)
> + if (sb_id == ID_BITMAP_NONE || sb_id == orig_id) {
> + mddev->bitmap_id = orig_id;
> return err;
> + }
>
> pr_info("md: %s: bitmap version mismatch, switching from %d to
> %d\n",
> mdname(mddev), orig_id, sb_id);
> @@ -6594,7 +6598,7 @@ static int md_bitmap_create(struct mddev
> *mddev)
> return 0;
> }
>
> -static void md_bitmap_destroy_nosysfs(struct mddev *mddev)
> +void md_bitmap_destroy_nosysfs(struct mddev *mddev)
> {
> if (!md_bitmap_registered(mddev))
> return;
> @@ -6612,6 +6616,16 @@ static void md_bitmap_destroy(struct
> mddev *mddev)
> md_bitmap_destroy_nosysfs(mddev);
> }
>
> +static void md_bitmap_set_none(struct mddev *mddev)
> +{
> + mddev->bitmap_id = ID_BITMAP_NONE;
> + if (!mddev_set_bitmap_ops_nosysfs(mddev))
> + return;
> +
> + if (!mddev_is_dm(mddev) && mddev->bitmap_ops->groups)
> + md_bitmap_sysfs_add(mddev);
> +}
> +
> int md_run(struct mddev *mddev)
> {
> int err;
> @@ -6821,6 +6835,10 @@ int md_run(struct mddev *mddev)
> if (mddev->sb_flags)
> md_update_sb(mddev, 0);
>
> + if (IS_ENABLED(CONFIG_MD_BITMAP) && !mddev->bitmap_info.file
> &&
> + !mddev->bitmap_info.offset)
> + md_bitmap_set_none(mddev);
> +
> md_new_event();
> return 0;
>
> @@ -7766,7 +7784,8 @@ static int set_bitmap_file(struct mddev
> *mddev, int fd)
> {
> int err = 0;
>
> - if (!md_bitmap_registered(mddev))
> + if (!md_bitmap_registered(mddev) ||
> + mddev->bitmap_id == ID_BITMAP_NONE)
> return -EINVAL;
>
> if (mddev->pers) {
> @@ -7831,10 +7850,12 @@ static int set_bitmap_file(struct mddev
> *mddev, int fd)
>
> if (err) {
> md_bitmap_destroy(mddev);
> + md_bitmap_set_none(mddev);
> fd = -1;
> }
> } else if (fd < 0) {
> md_bitmap_destroy(mddev);
> + md_bitmap_set_none(mddev);
> }
> }
>
> @@ -8141,12 +8162,16 @@ 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;
> + mddev->bitmap_id = ID_BITMAP;
> rv = md_bitmap_create(mddev);
> if (!rv)
> rv = mddev->bitmap_ops->load(mddev);
>
> - if (rv)
> + if (rv) {
> md_bitmap_destroy(mddev);
> + mddev->bitmap_info.offset = 0;
> + md_bitmap_set_none(mddev);
> + }
> } else {
> struct md_bitmap_stats stats;
>
> @@ -8174,6 +8199,7 @@ static int update_array_info(struct mddev
> *mddev, mdu_array_info_t *info)
> }
> md_bitmap_destroy(mddev);
> mddev->bitmap_info.offset = 0;
> + md_bitmap_set_none(mddev);
> }
> }
> md_update_sb(mddev, 1);
> diff --git a/drivers/md/md.h b/drivers/md/md.h
> index d3d4e2150dc8..52c378086046 100644
> --- a/drivers/md/md.h
> +++ b/drivers/md/md.h
> @@ -934,6 +934,9 @@ extern void md_allow_write(struct mddev
> *mddev);
> extern void md_wait_for_blocked_rdev(struct md_rdev *rdev,
> struct mddev *mddev);
> extern void md_set_array_sectors(struct mddev *mddev, sector_t
> array_sectors);
> extern int md_check_no_bitmap(struct mddev *mddev);
> +bool mddev_set_bitmap_ops_nosysfs(struct mddev *mddev);
> +int md_bitmap_create_nosysfs(struct mddev *mddev);
> +void md_bitmap_destroy_nosysfs(struct mddev *mddev);
> extern int md_integrity_register(struct mddev *mddev);
> extern int strict_strtoul_scaled(const char *cp, unsigned long
> *res, int scale);
next prev parent reply other threads:[~2026-04-25 8:44 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-04-25 2:46 [PATCH v13 0/3] md/md-bitmap: restore bitmap grow through sysfs Yu Kuai
2026-04-25 2:46 ` [PATCH v13 1/3] md: factor bitmap creation away from sysfs handling Yu Kuai
2026-04-25 8:30 ` Su Yue
2026-04-25 2:46 ` [PATCH v13 2/3] md/md-bitmap: split bitmap sysfs groups Yu Kuai
2026-04-25 8:36 ` Su Yue
2026-04-25 2:46 ` [PATCH v13 3/3] md/md-bitmap: add a none backend for bitmap grow Yu Kuai
2026-04-25 8:39 ` Su Yue [this message]
2026-04-25 2:49 ` [PATCH v13 0/3] md/md-bitmap: restore bitmap grow through sysfs Yu Kuai
2026-04-25 8:41 ` Su Yue
2026-04-28 8:21 ` Yu Kuai
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