* Re: [PATCH v2 11/20] md/md-llbitmap: don't skip reshape ranges from bitmap state
From: sashiko-bot @ 2026-06-24 6:58 UTC (permalink / raw)
To: Yu Kuai; +Cc: yukuai, linux-raid
In-Reply-To: <11d028037df1acf02db6d67a362ab02e96a7dd57.1782282042.git.yukuai@kernel.org>
Thank you for your contribution! Sashiko AI review found 2 potential issue(s) to consider:
Pre-existing issues:
- [Critical] Use-After-Free (UAF) of `llbitmap` memory during dynamic bitmap unregistration.
- [High] Signed integer overflow in `llbitmap_skip_sync_blocks` can cause premature resync termination.
--
commit 008d5398fa7aa1473594e503af861f03ef4f2548
Author: Yu Kuai <yukuai@fygo.io>
md/md-llbitmap: don't skip reshape ranges from bitmap state
Reshape progress is tracked by array metadata rather than llbitmap.
Do not let llbitmap skip_sync_blocks() suppress reshape ranges based on
stale bitmap state before the corresponding checkpoint is persisted.
> diff --git a/drivers/md/md-llbitmap.c b/drivers/md/md-llbitmap.c
> index d27993cfb13da..c62397743d9a0 100644
> --- a/drivers/md/md-llbitmap.c
> +++ b/drivers/md/md-llbitmap.c
> @@ -1647,6 +1647,14 @@ static sector_t llbitmap_skip_sync_blocks(struct mddev *mddev, sector_t offset)
> return 0;
> c = llbitmap_read(llbitmap, p);
>
> + /*
> + * Reshape progress is tracked by array metadata rather than llbitmap.
> + * Skipping reshape ranges from stale bitmap state can lose data after a
> + * restart before the corresponding bits are checkpointed to disk.
> + */
> + if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
> + return 0;
> +
> /* always skip unwritten blocks */
> if (c == BitUnwritten)
> return blocks;
[Severity: High]
This is a pre-existing issue, but since we are modifying this function, is
there a risk of signed integer overflow when returning blocks here?
If the array is extremely large and reserved bitmap space is small,
llbitmap->chunksize can be doubled during initialization until it exceeds
INT_MAX.
Because blocks is calculated earlier in this function as an int:
int blocks = llbitmap->chunksize - (offset & (llbitmap->chunksize - 1));
If chunksize exceeds INT_MAX, blocks could become negative.
When this negative value is implicitly cast to the sector_t (unsigned 64-bit)
return type, it becomes a massive positive number.
Could this cause md_do_sync() to jump to the end of the array and
prematurely abort the synchronization?
Would it be safer to change the type of blocks to unsigned long or sector_t?
[Severity: Critical]
This isn't a bug introduced by this patch, but looking at the teardown
sequence elsewhere in this file for dynamic bitmap unregistration, does
llbitmap_destroy() have a use-after-free vulnerability?
When clearing the bitmap at runtime, llbitmap_destroy() deletes the timer
and flushes the workqueues without setting the LLPageFlush flag:
timer_delete_sync(&llbitmap->pending_timer);
flush_workqueue(md_llbitmap_io_wq);
flush_workqueue(md_llbitmap_unplug_wq);
mddev->bitmap = NULL;
llbitmap_free_pages(llbitmap);
kfree(llbitmap);
If the daemon worker (md_llbitmap_daemon_fn) is running on the workqueue,
timer_delete_sync() might do nothing if the timer already fired. The
flush_workqueue() call then waits for the worker to finish.
Inside the worker, because LLPageFlush is not set and idle pages have an
expire of LONG_MAX, it sets restart = true and re-arms the timer:
if (!test_bit(LLPageFlush, &pctl->flags) &&
time_before(jiffies, pctl->expire)) {
restart = true;
continue;
}
...
if (restart)
mod_timer(&llbitmap->pending_timer, ...);
Once the worker finishes, flush_workqueue() returns and llbitmap is freed.
Does this leave the timer armed on freed memory, potentially causing memory
corruption when it fires?
--
Sashiko AI review · https://sashiko.dev/#/patchset/cover.1782282042.git.yukuai@kernel.org?part=11
^ permalink raw reply
* [PATCH v2 20/20] md/raid5: split reshape bios before bitmap accounting
From: Yu Kuai @ 2026-06-24 6:42 UTC (permalink / raw)
To: Song Liu, Yu Kuai; +Cc: Li Nan, Xiao Ni, Su Yue, linux-raid, linux-kernel
In-Reply-To: <cover.1782282042.git.yukuai@kernel.org>
From: Yu Kuai <yukuai@fygo.io>
Use the shared mddev_bio_split_at_reshape_offset() helper so RAID5
submits only one-side bios to llbitmap during reshape.
Signed-off-by: Yu Kuai <yukuai@fygo.io>
---
drivers/md/raid5.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index ac7ea483502f..fb346a3c4aa3 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -6181,6 +6181,14 @@ static bool raid5_make_request(struct mddev *mddev, struct bio * bi)
return true;
}
+ bi = mddev_bio_split_at_reshape_offset(mddev, bi, NULL,
+ &conf->bio_split);
+ if (!bi) {
+ if (rw == WRITE)
+ md_write_end(mddev);
+ return true;
+ }
+
logical_sector = bi->bi_iter.bi_sector & ~((sector_t)RAID5_STRIPE_SECTORS(conf)-1);
bi->bi_next = NULL;
--
2.51.0
^ permalink raw reply related
* [PATCH v2 19/20] md/raid5: wire llbitmap reshape lifecycle
From: Yu Kuai @ 2026-06-24 6:42 UTC (permalink / raw)
To: Song Liu, Yu Kuai; +Cc: Li Nan, Xiao Ni, Su Yue, linux-raid, linux-kernel
In-Reply-To: <cover.1782282042.git.yukuai@kernel.org>
From: Yu Kuai <yukuai@fygo.io>
Prepare llbitmap before RAID5 reshape starts, checkpoint the bitmap
before advancing reshape_position, and finish the llbitmap geometry
update when reshape completes.
Signed-off-by: Yu Kuai <yukuai@fygo.io>
---
drivers/md/raid5.c | 37 +++++++++++++++++++++++++++++++++++++
1 file changed, 37 insertions(+)
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 9de648f75dd0..ac7ea483502f 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -6430,6 +6430,13 @@ static sector_t reshape_request(struct mddev *mddev, sector_t sector_nr, int *sk
|| test_bit(MD_RECOVERY_INTR, &mddev->recovery));
if (atomic_read(&conf->reshape_stripes) != 0)
return 0;
+ if (md_bitmap_enabled(mddev, false) &&
+ mddev->bitmap_ops->reshape_mark &&
+ conf->reshape_safe != conf->reshape_progress) {
+ mddev->bitmap_ops->reshape_mark(mddev, conf->reshape_safe,
+ conf->reshape_progress);
+ mddev->bitmap_ops->unplug(mddev, true);
+ }
mddev->reshape_position = conf->reshape_progress;
mddev->curr_resync_completed = sector_nr;
if (!mddev->reshape_backwards)
@@ -6539,6 +6546,13 @@ static sector_t reshape_request(struct mddev *mddev, sector_t sector_nr, int *sk
|| test_bit(MD_RECOVERY_INTR, &mddev->recovery));
if (atomic_read(&conf->reshape_stripes) != 0)
goto ret;
+ if (md_bitmap_enabled(mddev, false) &&
+ mddev->bitmap_ops->reshape_mark &&
+ conf->reshape_safe != conf->reshape_progress) {
+ mddev->bitmap_ops->reshape_mark(mddev, conf->reshape_safe,
+ conf->reshape_progress);
+ mddev->bitmap_ops->unplug(mddev, true);
+ }
mddev->reshape_position = conf->reshape_progress;
mddev->curr_resync_completed = sector_nr;
if (!mddev->reshape_backwards)
@@ -8571,6 +8585,12 @@ static int raid5_start_reshape(struct mddev *mddev)
mdname(mddev));
return -EINVAL;
}
+ if (md_bitmap_enabled(mddev, false) &&
+ mddev->bitmap_id == ID_LLBITMAP) {
+ i = mddev->bitmap_ops->resize(mddev, mddev->dev_sectors, 0);
+ if (i)
+ return i;
+ }
atomic_set(&conf->reshape_stripes, 0);
spin_lock_irq(&conf->device_lock);
@@ -8655,10 +8675,19 @@ static int raid5_start_reshape(struct mddev *mddev)
*/
static void end_reshape(struct r5conf *conf)
{
+ struct mddev *mddev = conf->mddev;
if (!test_bit(MD_RECOVERY_INTR, &conf->mddev->recovery)) {
struct md_rdev *rdev;
+ if (md_bitmap_enabled(mddev, false) &&
+ mddev->bitmap_ops->reshape_mark &&
+ conf->reshape_safe != conf->reshape_progress) {
+ mddev->bitmap_ops->reshape_mark(mddev, conf->reshape_safe,
+ conf->reshape_progress);
+ mddev->bitmap_ops->unplug(mddev, true);
+ }
+
spin_lock_irq(&conf->device_lock);
conf->previous_raid_disks = conf->raid_disks;
md_finish_reshape(conf->mddev);
@@ -8685,8 +8714,16 @@ static void raid5_finish_reshape(struct mddev *mddev)
{
struct r5conf *conf = mddev->private;
struct md_rdev *rdev;
+ bool llbitmap = mddev->bitmap_id == ID_LLBITMAP &&
+ md_bitmap_enabled(mddev, false);
if (!test_bit(MD_RECOVERY_INTR, &mddev->recovery)) {
+ if (llbitmap && mddev->bitmap_ops->reshape_finish)
+ mddev->bitmap_ops->reshape_finish(mddev);
+ if (llbitmap) {
+ mddev->resync_offset = 0;
+ mddev->resync_max_sectors = mddev->dev_sectors;
+ }
if (mddev->delta_disks <= 0) {
int d;
--
2.51.0
^ permalink raw reply related
* [PATCH v2 18/20] md/raid5: reject llbitmap reshape when md chunk shrinks
From: Yu Kuai @ 2026-06-24 6:42 UTC (permalink / raw)
To: Song Liu, Yu Kuai; +Cc: Li Nan, Xiao Ni, Su Yue, linux-raid, linux-kernel
In-Reply-To: <cover.1782282042.git.yukuai@kernel.org>
From: Yu Kuai <yukuai@fygo.io>
llbitmap reshape keeps one live bitmap and cannot safely make an
existing bitmap bit cover a smaller data range.
The llbitmap chunksize itself will not shrink when mddev->chunk_sectors
stays the same or grows. However, shrinking mddev->chunk_sectors shrinks
sectors_per_chunk used by raid5_bitmap_sector_map(). That can shrink the
effective data range covered by each bit across the old and new RAID5
geometry. Reject that reshape while llbitmap is active.
Signed-off-by: Yu Kuai <yukuai@fygo.io>
---
drivers/md/raid5.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 1613a42cc25d..9de648f75dd0 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -8506,6 +8506,9 @@ static int check_reshape(struct mddev *mddev)
if (!check_stripe_cache(mddev))
return -ENOSPC;
+ if (mddev->bitmap_id == ID_LLBITMAP &&
+ mddev->new_chunk_sectors < mddev->chunk_sectors)
+ return -EOPNOTSUPP;
if (mddev->new_chunk_sectors > mddev->chunk_sectors ||
mddev->delta_disks > 0)
if (resize_chunks(conf,
--
2.51.0
^ permalink raw reply related
* [PATCH v2 17/20] md/raid5: add exact old and new llbitmap mapping helpers
From: Yu Kuai @ 2026-06-24 6:42 UTC (permalink / raw)
To: Song Liu, Yu Kuai; +Cc: Li Nan, Xiao Ni, Su Yue, linux-raid, linux-kernel
In-Reply-To: <cover.1782282042.git.yukuai@kernel.org>
From: Yu Kuai <yukuai@fygo.io>
Teach RAID5 to export exact old and new llbitmap mappings and the
corresponding sync and array sizes for reshape-aware bitmap users.
Signed-off-by: Yu Kuai <yukuai@fygo.io>
---
drivers/md/raid5.c | 70 ++++++++++++++++++++++++++++++++++------------
1 file changed, 52 insertions(+), 18 deletions(-)
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 0c5c9fb0606e..1613a42cc25d 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -5942,25 +5942,43 @@ static enum reshape_loc get_reshape_loc(struct mddev *mddev,
return LOC_BEHIND_RESHAPE;
}
-static void raid5_bitmap_sector(struct mddev *mddev, sector_t *offset,
- unsigned long *sectors)
+static void raid5_bitmap_sector_map(struct mddev *mddev, sector_t *offset,
+ unsigned long *sectors,
+ bool previous)
{
struct r5conf *conf = mddev->private;
sector_t start = *offset;
sector_t end = start + *sectors;
- sector_t prev_start = start;
- sector_t prev_end = end;
int sectors_per_chunk;
- enum reshape_loc loc;
int dd_idx;
- sectors_per_chunk = conf->chunk_sectors *
- (conf->raid_disks - conf->max_degraded);
+ if (previous)
+ sectors_per_chunk = conf->prev_chunk_sectors *
+ (conf->previous_raid_disks - conf->max_degraded);
+ else
+ sectors_per_chunk = conf->chunk_sectors *
+ (conf->raid_disks - conf->max_degraded);
start = round_down(start, sectors_per_chunk);
end = round_up(end, sectors_per_chunk);
- start = raid5_compute_sector(conf, start, 0, &dd_idx, NULL);
- end = raid5_compute_sector(conf, end, 0, &dd_idx, NULL);
+ start = raid5_compute_sector(conf, start, previous, &dd_idx, NULL);
+ end = raid5_compute_sector(conf, end, previous, &dd_idx, NULL);
+ *offset = start;
+ *sectors = end - start;
+}
+
+static void raid5_bitmap_sector(struct mddev *mddev, sector_t *offset,
+ unsigned long *sectors)
+{
+ struct r5conf *conf = mddev->private;
+ sector_t start = *offset;
+ sector_t end = start + *sectors;
+ sector_t prev_start = start;
+ unsigned long prev_sectors = end - start;
+ enum reshape_loc loc;
+
+ raid5_bitmap_sector_map(mddev, &start, sectors, false);
+ end = start + *sectors;
/*
* For LOC_INSIDE_RESHAPE, this IO will wait for reshape to make
@@ -5969,17 +5987,10 @@ static void raid5_bitmap_sector(struct mddev *mddev, sector_t *offset,
loc = get_reshape_loc(mddev, conf, prev_start);
if (likely(loc != LOC_AHEAD_OF_RESHAPE)) {
*offset = start;
- *sectors = end - start;
return;
}
- sectors_per_chunk = conf->prev_chunk_sectors *
- (conf->previous_raid_disks - conf->max_degraded);
- prev_start = round_down(prev_start, sectors_per_chunk);
- prev_end = round_down(prev_end, sectors_per_chunk);
-
- prev_start = raid5_compute_sector(conf, prev_start, 1, &dd_idx, NULL);
- prev_end = raid5_compute_sector(conf, prev_end, 1, &dd_idx, NULL);
+ raid5_bitmap_sector_map(mddev, &prev_start, &prev_sectors, true);
/*
* for LOC_AHEAD_OF_RESHAPE, reshape can make progress before this IO
@@ -5987,7 +5998,7 @@ static void raid5_bitmap_sector(struct mddev *mddev, sector_t *offset,
* we set bits for both.
*/
*offset = min(start, prev_start);
- *sectors = max(end, prev_end) - *offset;
+ *sectors = max(end, prev_start + prev_sectors) - *offset;
}
static enum stripe_result make_stripe_request(struct mddev *mddev,
@@ -9049,6 +9060,20 @@ static void raid5_prepare_suspend(struct mddev *mddev)
wake_up(&conf->wait_for_reshape);
}
+static sector_t raid5_bitmap_sync_size(struct mddev *mddev, bool previous)
+{
+ return mddev->dev_sectors;
+}
+
+static sector_t raid5_bitmap_array_sectors(struct mddev *mddev, bool previous)
+{
+ struct r5conf *conf = mddev->private;
+
+ if (previous)
+ return raid5_size(mddev, 0, 0);
+ return raid5_size(mddev, mddev->dev_sectors, conf->raid_disks);
+}
+
static struct md_personality raid6_personality =
{
.head = {
@@ -9078,6 +9103,9 @@ static struct md_personality raid6_personality =
.change_consistency_policy = raid5_change_consistency_policy,
.prepare_suspend = raid5_prepare_suspend,
.bitmap_sector = raid5_bitmap_sector,
+ .bitmap_sector_map = raid5_bitmap_sector_map,
+ .bitmap_sync_size = raid5_bitmap_sync_size,
+ .bitmap_array_sectors = raid5_bitmap_array_sectors,
};
static struct md_personality raid5_personality =
{
@@ -9108,6 +9136,9 @@ static struct md_personality raid5_personality =
.change_consistency_policy = raid5_change_consistency_policy,
.prepare_suspend = raid5_prepare_suspend,
.bitmap_sector = raid5_bitmap_sector,
+ .bitmap_sector_map = raid5_bitmap_sector_map,
+ .bitmap_sync_size = raid5_bitmap_sync_size,
+ .bitmap_array_sectors = raid5_bitmap_array_sectors,
};
static struct md_personality raid4_personality =
@@ -9139,6 +9170,9 @@ static struct md_personality raid4_personality =
.change_consistency_policy = raid5_change_consistency_policy,
.prepare_suspend = raid5_prepare_suspend,
.bitmap_sector = raid5_bitmap_sector,
+ .bitmap_sector_map = raid5_bitmap_sector_map,
+ .bitmap_sync_size = raid5_bitmap_sync_size,
+ .bitmap_array_sectors = raid5_bitmap_array_sectors,
};
static int __init raid5_init(void)
--
2.51.0
^ permalink raw reply related
* [PATCH v2 16/20] md/raid10: split reshape bios before bitmap accounting
From: Yu Kuai @ 2026-06-24 6:42 UTC (permalink / raw)
To: Song Liu, Yu Kuai; +Cc: Li Nan, Xiao Ni, Su Yue, linux-raid, linux-kernel
In-Reply-To: <cover.1782282042.git.yukuai@kernel.org>
From: Yu Kuai <yukuai@fygo.io>
Use the shared mddev_bio_split_at_reshape_offset() helper so RAID10
submits only one-side bios to llbitmap during reshape.
Signed-off-by: Yu Kuai <yukuai@fygo.io>
---
drivers/md/raid10.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index e50e4adee389..fd364a2e2fd9 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -1911,6 +1911,12 @@ static bool raid10_make_request(struct mddev *mddev, struct bio *bio)
sectors = chunk_sects -
(bio->bi_iter.bi_sector &
(chunk_sects - 1));
+
+ bio = mddev_bio_split_at_reshape_offset(mddev, bio, §ors,
+ &conf->bio_split);
+ if (!bio)
+ return true;
+
if (!__make_request(mddev, bio, sectors))
md_write_end(mddev);
--
2.51.0
^ permalink raw reply related
* [PATCH v2 15/20] md/raid10: wire llbitmap reshape lifecycle
From: Yu Kuai @ 2026-06-24 6:42 UTC (permalink / raw)
To: Song Liu, Yu Kuai; +Cc: Li Nan, Xiao Ni, Su Yue, linux-raid, linux-kernel
In-Reply-To: <cover.1782282042.git.yukuai@kernel.org>
From: Yu Kuai <yukuai@fygo.io>
Prepare llbitmap before RAID10 starts growing, checkpoint the bitmap
before advancing reshape_position, finish the llbitmap geometry update
when reshape completes, and export the old and new tracked sizes.
Signed-off-by: Yu Kuai <yukuai@fygo.io>
---
drivers/md/raid10.c | 39 +++++++++++++++++++++++++++++++++++++++
1 file changed, 39 insertions(+)
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 1242b8d3bb6b..e50e4adee389 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -4394,6 +4394,12 @@ static int raid10_start_reshape(struct mddev *mddev)
if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
return -EBUSY;
+ if (md_bitmap_enabled(mddev, false) &&
+ mddev->bitmap_ops->reshape_can_start) {
+ ret = mddev->bitmap_ops->reshape_can_start(mddev);
+ if (ret)
+ return ret;
+ }
if (setup_geo(&new, mddev, geo_start) != conf->copies)
return -EINVAL;
@@ -4707,6 +4713,13 @@ static sector_t reshape_request(struct mddev *mddev, sector_t sector_nr,
time_after(jiffies, conf->reshape_checkpoint + 10*HZ)) {
/* Need to update reshape_position in metadata */
wait_barrier(conf, false);
+ if (md_bitmap_enabled(mddev, false) &&
+ mddev->bitmap_ops->reshape_mark &&
+ conf->reshape_safe != conf->reshape_progress) {
+ mddev->bitmap_ops->reshape_mark(mddev, conf->reshape_safe,
+ conf->reshape_progress);
+ mddev->bitmap_ops->unplug(mddev, true);
+ }
mddev->reshape_position = conf->reshape_progress;
if (mddev->reshape_backwards)
mddev->curr_resync_completed = raid10_size(mddev, 0, 0)
@@ -4905,9 +4918,19 @@ static void reshape_request_write(struct mddev *mddev, struct r10bio *r10_bio)
static void end_reshape(struct r10conf *conf)
{
+ struct mddev *mddev = conf->mddev;
+
if (test_bit(MD_RECOVERY_INTR, &conf->mddev->recovery))
return;
+ if (md_bitmap_enabled(mddev, false) &&
+ mddev->bitmap_ops->reshape_mark &&
+ conf->reshape_safe != conf->reshape_progress) {
+ mddev->bitmap_ops->reshape_mark(mddev, conf->reshape_safe,
+ conf->reshape_progress);
+ mddev->bitmap_ops->unplug(mddev, true);
+ }
+
spin_lock_irq(&conf->device_lock);
conf->prev = conf->geo;
md_finish_reshape(conf->mddev);
@@ -5039,10 +5062,15 @@ static void end_reshape_request(struct r10bio *r10_bio)
static void raid10_finish_reshape(struct mddev *mddev)
{
struct r10conf *conf = mddev->private;
+ bool llbitmap = mddev->bitmap_id == ID_LLBITMAP &&
+ md_bitmap_enabled(mddev, false);
if (test_bit(MD_RECOVERY_INTR, &mddev->recovery))
return;
+ if (llbitmap && mddev->bitmap_ops->reshape_finish)
+ mddev->bitmap_ops->reshape_finish(mddev);
+
if (mddev->delta_disks > 0) {
if (mddev->resync_offset > mddev->resync_max_sectors) {
mddev->resync_offset = mddev->resync_max_sectors;
@@ -5069,6 +5097,15 @@ static void raid10_finish_reshape(struct mddev *mddev)
mddev->reshape_backwards = 0;
}
+static sector_t raid10_bitmap_sync_size(struct mddev *mddev, bool previous)
+{
+ struct r10conf *conf = mddev->private;
+
+ if (previous)
+ return raid10_size(mddev, 0, 0);
+ return raid10_size(mddev, 0, conf->geo.raid_disks);
+}
+
static struct md_personality raid10_personality =
{
.head = {
@@ -5095,6 +5132,8 @@ static struct md_personality raid10_personality =
.start_reshape = raid10_start_reshape,
.finish_reshape = raid10_finish_reshape,
.update_reshape_pos = raid10_update_reshape_pos,
+ .bitmap_sync_size = raid10_bitmap_sync_size,
+ .bitmap_array_sectors = raid10_bitmap_sync_size,
};
static int __init raid10_init(void)
--
2.51.0
^ permalink raw reply related
* [PATCH v2 14/20] md/raid10: reject llbitmap reshape when md chunk shrinks
From: Yu Kuai @ 2026-06-24 6:42 UTC (permalink / raw)
To: Song Liu, Yu Kuai; +Cc: Li Nan, Xiao Ni, Su Yue, linux-raid, linux-kernel
In-Reply-To: <cover.1782282042.git.yukuai@kernel.org>
From: Yu Kuai <yukuai@fygo.io>
llbitmap reshape keeps one live bitmap and cannot safely make an
existing bitmap bit cover a smaller data range.
The llbitmap chunksize itself will not shrink when mddev->chunk_sectors
stays the same or grows. However, shrinking mddev->chunk_sectors can
shrink the effective data range covered by each bit for the RAID10
reshape geometry. Reject that reshape while llbitmap is active.
Signed-off-by: Yu Kuai <yukuai@fygo.io>
---
drivers/md/raid10.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 0a3cfdd3f5df..1242b8d3bb6b 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -4284,6 +4284,10 @@ static int raid10_check_reshape(struct mddev *mddev)
if (conf->geo.far_copies != 1 && !conf->geo.far_offset)
return -EINVAL;
+ if (mddev->bitmap_id == ID_LLBITMAP &&
+ mddev->new_chunk_sectors &&
+ mddev->new_chunk_sectors < mddev->chunk_sectors)
+ return -EOPNOTSUPP;
if (setup_geo(&geo, mddev, geo_start) != conf->copies)
/* mustn't change number of copies */
--
2.51.0
^ permalink raw reply related
* [PATCH v2 13/20] md/md-llbitmap: clamp state-machine walks to tracked bits
From: Yu Kuai @ 2026-06-24 6:42 UTC (permalink / raw)
To: Song Liu, Yu Kuai; +Cc: Li Nan, Xiao Ni, Su Yue, linux-raid, linux-kernel
In-Reply-To: <cover.1782282042.git.yukuai@kernel.org>
From: Yu Kuai <yukuai@fygo.io>
llbitmap_state_machine() can be called with an end bit beyond
llbitmap->chunks. In particular, llbitmap_cond_end_sync() passes
sector >> chunkshift, and sector can reach the tracked boundary
exactly.
Clamp the state-machine range to llbitmap->chunks so it cannot walk
past the tracked bitmap.
Signed-off-by: Yu Kuai <yukuai@fygo.io>
---
drivers/md/md-llbitmap.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/md/md-llbitmap.c b/drivers/md/md-llbitmap.c
index 00b77ecd600b..581ee9e4a346 100644
--- a/drivers/md/md-llbitmap.c
+++ b/drivers/md/md-llbitmap.c
@@ -983,7 +983,10 @@ static enum llbitmap_state llbitmap_state_machine(struct llbitmap *llbitmap,
llbitmap_init_state(llbitmap);
return BitNone;
}
-
+ if (start >= llbitmap->chunks)
+ return BitNone;
+ if (end >= llbitmap->chunks)
+ end = llbitmap->chunks - 1;
while (start <= end) {
enum llbitmap_state c = llbitmap_read(llbitmap, start);
--
2.51.0
^ permalink raw reply related
* [PATCH v2 12/20] md/md-llbitmap: remap checkpointed bits as reshape progresses
From: Yu Kuai @ 2026-06-24 6:42 UTC (permalink / raw)
To: Song Liu, Yu Kuai; +Cc: Li Nan, Xiao Ni, Su Yue, linux-raid, linux-kernel
In-Reply-To: <cover.1782282042.git.yukuai@kernel.org>
From: Yu Kuai <yukuai@fygo.io>
Merge checkpointed old llbitmap state forward as reshape_position
advances and record the checkpoint remap through reshape_mark().
Signed-off-by: Yu Kuai <yukuai@fygo.io>
---
drivers/md/md-llbitmap.c | 172 +++++++++++++++++++++++++++++++++++++++
1 file changed, 172 insertions(+)
diff --git a/drivers/md/md-llbitmap.c b/drivers/md/md-llbitmap.c
index c62397743d9a..00b77ecd600b 100644
--- a/drivers/md/md-llbitmap.c
+++ b/drivers/md/md-llbitmap.c
@@ -502,6 +502,14 @@ static void llbitmap_map_layout(struct llbitmap *llbitmap, sector_t *offset,
else if (!previous && llbitmap->mddev->pers->bitmap_sector)
llbitmap->mddev->pers->bitmap_sector(llbitmap->mddev, offset,
sectors);
+
+ limit = llbitmap_personality_sync_size(llbitmap, previous);
+ start = *offset;
+ end = start + *sectors;
+ if (start >= limit)
+ *sectors = 0;
+ else if (end > limit)
+ *sectors = limit - start;
}
static void llbitmap_encode_range(struct llbitmap *llbitmap, sector_t *offset,
@@ -906,6 +914,33 @@ static int llbitmap_prepare_resize(struct llbitmap *llbitmap,
return 0;
}
+static enum llbitmap_state
+llbitmap_rmerge_state(struct llbitmap *llbitmap,
+ enum llbitmap_state dst,
+ enum llbitmap_state src)
+{
+ bool level_456 = raid_is_456(llbitmap->mddev);
+
+ if (dst == BitNeedSync || dst == BitSyncing ||
+ src == BitNeedSync || src == BitSyncing)
+ return BitNeedSync;
+
+ if (dst == BitDirty || src == BitDirty)
+ return BitDirty;
+
+ /*
+ * Reshape generates valid target parity/data for both already-written
+ * and not-yet-written regions in the checkpointed range, so a mix of
+ * clean and unwritten still results in a clean destination bit.
+ */
+ if (level_456 && ((dst == BitClean && src == BitUnwritten) ||
+ (src == BitClean && dst == BitUnwritten)))
+ return BitClean;
+ if (dst == BitClean || src == BitClean)
+ return BitClean;
+ return BitUnwritten;
+}
+
static void llbitmap_init_state(struct llbitmap *llbitmap)
{
struct mddev *mddev = llbitmap->mddev;
@@ -1799,6 +1834,120 @@ static int llbitmap_reshape_can_start(struct mddev *mddev)
return ret;
}
+struct llbitmap_reshape_range {
+ sector_t offset;
+ unsigned long sectors;
+ sector_t start;
+ sector_t end;
+};
+
+static enum llbitmap_state
+llbitmap_reshape_init_dst(struct llbitmap *llbitmap, unsigned long dst,
+ const struct llbitmap_reshape_range *new)
+{
+ u64 bit_start = (u64)dst * llbitmap->reshape_chunksize;
+ u64 bit_end = bit_start + llbitmap->reshape_chunksize;
+
+ if (!llbitmap->mddev->reshape_backwards)
+ return bit_start < new->offset ? llbitmap_read(llbitmap, dst) :
+ BitUnwritten;
+ return bit_end > new->end ? llbitmap_read(llbitmap, dst) : BitUnwritten;
+}
+
+static void llbitmap_reshape_dst_range(struct llbitmap *llbitmap,
+ unsigned long dst,
+ const struct llbitmap_reshape_range *new,
+ struct llbitmap_reshape_range *dst_range)
+{
+ sector_t dst_bit_start = (sector_t)dst * llbitmap->reshape_chunksize;
+
+ dst_range->start = max(dst_bit_start, new->offset);
+ dst_range->end = min(dst_bit_start + llbitmap->reshape_chunksize,
+ new->end);
+ dst_range->offset = dst_range->start;
+ dst_range->sectors = dst_range->end - dst_range->start;
+}
+
+static void llbitmap_reshape_map_range(struct llbitmap *llbitmap,
+ sector_t lo, sector_t hi,
+ bool previous,
+ struct llbitmap_reshape_range *range)
+{
+ range->offset = lo;
+ range->sectors = hi - lo;
+ llbitmap_map_layout(llbitmap, &range->offset, &range->sectors, previous);
+ range->start = range->offset;
+ range->end = range->offset + range->sectors;
+}
+
+static bool llbitmap_reshape_src_range(const struct llbitmap_reshape_range *old,
+ const struct llbitmap_reshape_range *new,
+ const struct llbitmap_reshape_range *dst,
+ struct llbitmap_reshape_range *src)
+{
+ if (!old->sectors)
+ return false;
+
+ src->start = old->offset +
+ mul_u64_u64_div_u64(dst->start - new->offset,
+ old->sectors, new->sectors);
+ src->end = old->offset +
+ mul_u64_u64_div_u64_roundup(dst->end - new->offset,
+ old->sectors, new->sectors);
+ if (src->end > old->end)
+ src->end = old->end;
+ src->offset = src->start;
+ src->sectors = src->end - src->start;
+
+ return src->sectors;
+}
+
+static enum llbitmap_state llbitmap_rmerge_src(struct llbitmap *llbitmap,
+ enum llbitmap_state state,
+ const struct llbitmap_reshape_range *src)
+{
+ unsigned long bit = div64_u64(src->start, llbitmap->chunksize);
+ unsigned long end = div64_u64(src->end - 1, llbitmap->chunksize);
+
+ while (bit <= end) {
+ enum llbitmap_state src_state = llbitmap_read(llbitmap, bit);
+
+ state = llbitmap_rmerge_state(llbitmap, state, src_state);
+ bit++;
+ }
+
+ return state;
+}
+
+static void llbitmap_reshape_merge(struct llbitmap *llbitmap,
+ const struct llbitmap_reshape_range *old,
+ const struct llbitmap_reshape_range *new)
+{
+ unsigned long dst_start;
+ unsigned long dst_end;
+ unsigned long dst;
+
+ if (!new->sectors)
+ return;
+
+ dst_start = div64_u64(new->offset, llbitmap->reshape_chunksize);
+ dst_end = div64_u64(new->end - 1, llbitmap->reshape_chunksize);
+
+ for (dst = dst_start; dst <= dst_end; dst++) {
+ struct llbitmap_reshape_range dst_range;
+ struct llbitmap_reshape_range src;
+ enum llbitmap_state state;
+
+ llbitmap_reshape_dst_range(llbitmap, dst, new, &dst_range);
+ state = llbitmap_reshape_init_dst(llbitmap, dst, new);
+ if (llbitmap_reshape_src_range(old, new, &dst_range, &src))
+ state = llbitmap_rmerge_src(llbitmap, state, &src);
+ else
+ state = llbitmap_rmerge_state(llbitmap, state, BitUnwritten);
+ llbitmap_write(llbitmap, state, dst);
+ }
+}
+
static void llbitmap_reshape_finish(struct mddev *mddev)
{
struct llbitmap *llbitmap = mddev->bitmap;
@@ -1823,6 +1972,28 @@ static void llbitmap_reshape_finish(struct mddev *mddev)
mddev->pers->quiesce(mddev, 0);
}
+static void llbitmap_reshape_mark(struct mddev *mddev, sector_t old_pos,
+ sector_t new_pos)
+{
+ struct llbitmap *llbitmap = mddev->bitmap;
+ sector_t lo;
+ sector_t hi;
+ struct llbitmap_reshape_range old;
+ struct llbitmap_reshape_range new;
+
+ if (!llbitmap || old_pos == new_pos)
+ return;
+
+ lo = min(old_pos, new_pos);
+ hi = max(old_pos, new_pos);
+ if (!hi)
+ return;
+
+ llbitmap_reshape_map_range(llbitmap, lo, hi, true, &old);
+ llbitmap_reshape_map_range(llbitmap, lo, hi, false, &new);
+ llbitmap_reshape_merge(llbitmap, &old, &new);
+}
+
static void llbitmap_write_sb(struct llbitmap *llbitmap)
{
int nr_blocks = DIV_ROUND_UP(BITMAP_DATA_OFFSET, llbitmap->io_size);
@@ -2122,6 +2293,7 @@ static struct bitmap_operations llbitmap_ops = {
.prepare_range = llbitmap_prepare_range,
.reshape_finish = llbitmap_reshape_finish,
.reshape_can_start = llbitmap_reshape_can_start,
+ .reshape_mark = llbitmap_reshape_mark,
.write_all = llbitmap_write_all,
.groups = md_llbitmap_groups,
--
2.51.0
^ permalink raw reply related
* [PATCH v2 11/20] md/md-llbitmap: don't skip reshape ranges from bitmap state
From: Yu Kuai @ 2026-06-24 6:42 UTC (permalink / raw)
To: Song Liu, Yu Kuai; +Cc: Li Nan, Xiao Ni, Su Yue, linux-raid, linux-kernel
In-Reply-To: <cover.1782282042.git.yukuai@kernel.org>
From: Yu Kuai <yukuai@fygo.io>
Reshape progress is tracked by array metadata rather than llbitmap.
Do not let llbitmap skip_sync_blocks() suppress reshape ranges based on
stale bitmap state before the corresponding checkpoint is persisted.
Signed-off-by: Yu Kuai <yukuai@fygo.io>
---
drivers/md/md-llbitmap.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/drivers/md/md-llbitmap.c b/drivers/md/md-llbitmap.c
index d27993cfb13d..c62397743d9a 100644
--- a/drivers/md/md-llbitmap.c
+++ b/drivers/md/md-llbitmap.c
@@ -1647,6 +1647,14 @@ static sector_t llbitmap_skip_sync_blocks(struct mddev *mddev, sector_t offset)
return 0;
c = llbitmap_read(llbitmap, p);
+ /*
+ * Reshape progress is tracked by array metadata rather than llbitmap.
+ * Skipping reshape ranges from stale bitmap state can lose data after a
+ * restart before the corresponding bits are checkpointed to disk.
+ */
+ if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
+ return 0;
+
/* always skip unwritten blocks */
if (c == BitUnwritten)
return blocks;
--
2.51.0
^ permalink raw reply related
* [PATCH v2 10/20] md/md-llbitmap: add reshape range mapping helpers
From: Yu Kuai @ 2026-06-24 6:42 UTC (permalink / raw)
To: Song Liu, Yu Kuai; +Cc: Li Nan, Xiao Ni, Su Yue, linux-raid, linux-kernel
In-Reply-To: <cover.1782282042.git.yukuai@kernel.org>
From: Yu Kuai <yukuai@fygo.io>
Teach llbitmap to choose old versus new geometry during reshape and to
encode exact bitmap ranges for the active geometry.
This is the mapping groundwork for checkpoint remapping.
Signed-off-by: Yu Kuai <yukuai@fygo.io>
---
drivers/md/md-llbitmap.c | 96 ++++++++++++++++++++++++++++++++++++++--
1 file changed, 92 insertions(+), 4 deletions(-)
diff --git a/drivers/md/md-llbitmap.c b/drivers/md/md-llbitmap.c
index 11fede1fc79f..d27993cfb13d 100644
--- a/drivers/md/md-llbitmap.c
+++ b/drivers/md/md-llbitmap.c
@@ -9,6 +9,7 @@
#include <linux/sched.h>
#include <linux/list.h>
#include <linux/file.h>
+#include <linux/math64.h>
#include <linux/seq_file.h>
#include <trace/events/block.h>
@@ -449,6 +450,16 @@ static sector_t llbitmap_personality_sync_size(struct llbitmap *llbitmap,
return mddev->pers->bitmap_sync_size(mddev, previous);
}
+static sector_t llbitmap_logical_size(struct llbitmap *llbitmap, bool previous)
+{
+ struct mddev *mddev = llbitmap->mddev;
+
+ if (!llbitmap_reshaping(llbitmap) || !mddev->private || !mddev->pers ||
+ !mddev->pers->bitmap_array_sectors)
+ return llbitmap_personality_sync_size(llbitmap, previous);
+ return mddev->pers->bitmap_array_sectors(mddev, previous);
+}
+
static void llbitmap_refresh_reshape(struct llbitmap *llbitmap)
{
unsigned long old_chunks = DIV_ROUND_UP_SECTOR_T(llbitmap->sync_size,
@@ -466,6 +477,52 @@ static void llbitmap_refresh_reshape(struct llbitmap *llbitmap)
llbitmap->chunks = max(old_chunks, llbitmap->reshape_chunks);
}
+static void llbitmap_map_layout(struct llbitmap *llbitmap, sector_t *offset,
+ unsigned long *sectors, bool previous)
+{
+ sector_t limit = llbitmap_logical_size(llbitmap, previous);
+ sector_t start = *offset;
+ sector_t end = start + *sectors;
+
+ if (start >= limit) {
+ *sectors = 0;
+ return;
+ }
+ if (end > limit)
+ end = limit;
+
+ *offset = start;
+ *sectors = end - start;
+ if (!*sectors)
+ return;
+
+ if (llbitmap->mddev->pers->bitmap_sector_map)
+ llbitmap->mddev->pers->bitmap_sector_map(llbitmap->mddev, offset,
+ sectors, previous);
+ else if (!previous && llbitmap->mddev->pers->bitmap_sector)
+ llbitmap->mddev->pers->bitmap_sector(llbitmap->mddev, offset,
+ sectors);
+}
+
+static void llbitmap_encode_range(struct llbitmap *llbitmap, sector_t *offset,
+ unsigned long *sectors, bool previous)
+{
+ unsigned long chunksize = previous ? llbitmap->chunksize :
+ llbitmap->reshape_chunksize;
+ u64 start;
+ u64 end;
+
+ if (!*sectors) {
+ *offset = 0;
+ return;
+ }
+
+ start = div64_u64(*offset, chunksize);
+ end = div64_u64(*offset + *sectors - 1, chunksize);
+ *offset = (sector_t)start << llbitmap->chunkshift;
+ *sectors = (end - start + 1) << llbitmap->chunkshift;
+}
+
static enum llbitmap_state llbitmap_read(struct llbitmap *llbitmap, loff_t pos)
{
unsigned int idx;
@@ -1376,11 +1433,32 @@ static void llbitmap_destroy(struct mddev *mddev)
mutex_unlock(&mddev->bitmap_info.mutex);
}
+static bool llbitmap_map_previous(struct llbitmap *llbitmap, sector_t offset,
+ unsigned long sectors)
+{
+ struct mddev *mddev = llbitmap->mddev;
+ sector_t boundary = mddev->reshape_position;
+
+ if (!llbitmap_reshaping(llbitmap))
+ return false;
+
+ WARN_ON_ONCE(sectors && offset < boundary && offset + sectors > boundary);
+
+ return mddev->reshape_backwards ? offset < boundary : offset >= boundary;
+}
+
static void llbitmap_prepare_range(struct mddev *mddev, sector_t *offset,
unsigned long *sectors)
{
- if (mddev->pers->bitmap_sector)
- mddev->pers->bitmap_sector(mddev, offset, sectors);
+ struct llbitmap *llbitmap = mddev->bitmap;
+ bool previous;
+
+ if (!llbitmap)
+ return;
+
+ previous = llbitmap_map_previous(llbitmap, *offset, *sectors);
+ llbitmap_map_layout(llbitmap, offset, sectors, previous);
+ llbitmap_encode_range(llbitmap, offset, sectors, previous);
}
static void llbitmap_start_write(struct mddev *mddev, sector_t offset,
@@ -1549,7 +1627,11 @@ static bool llbitmap_blocks_synced(struct mddev *mddev, sector_t offset)
{
struct llbitmap *llbitmap = mddev->bitmap;
unsigned long p = offset >> llbitmap->chunkshift;
- enum llbitmap_state c = llbitmap_read(llbitmap, p);
+ enum llbitmap_state c;
+
+ if (p >= llbitmap->chunks)
+ return false;
+ c = llbitmap_read(llbitmap, p);
return c == BitClean || c == BitDirty || c == BitCleanUnwritten;
}
@@ -1559,7 +1641,11 @@ static sector_t llbitmap_skip_sync_blocks(struct mddev *mddev, sector_t offset)
struct llbitmap *llbitmap = mddev->bitmap;
unsigned long p = offset >> llbitmap->chunkshift;
int blocks = llbitmap->chunksize - (offset & (llbitmap->chunksize - 1));
- enum llbitmap_state c = llbitmap_read(llbitmap, p);
+ enum llbitmap_state c;
+
+ if (p >= llbitmap->chunks)
+ return 0;
+ c = llbitmap_read(llbitmap, p);
/* always skip unwritten blocks */
if (c == BitUnwritten)
@@ -1604,6 +1690,8 @@ static bool llbitmap_start_sync(struct mddev *mddev, sector_t offset,
* if md_do_sync() loop more times.
*/
*blocks = llbitmap->chunksize - (offset & (llbitmap->chunksize - 1));
+ if (p >= llbitmap->chunks)
+ return false;
state = llbitmap_state_machine(llbitmap, p, p, BitmapActionStartsync);
return state == BitSyncing || state == BitSyncingUnwritten;
}
--
2.51.0
^ permalink raw reply related
* [PATCH v2 09/20] md/md-llbitmap: refuse reshape while llbitmap still needs sync
From: Yu Kuai @ 2026-06-24 6:42 UTC (permalink / raw)
To: Song Liu, Yu Kuai; +Cc: Li Nan, Xiao Ni, Su Yue, linux-raid, linux-kernel
In-Reply-To: <cover.1782282042.git.yukuai@kernel.org>
From: Yu Kuai <yukuai@fygo.io>
Reject reshape when llbitmap still contains NeedSync or Syncing bits.
This keeps reshape from starting until the current llbitmap state has
been reconciled.
Signed-off-by: Yu Kuai <yukuai@fygo.io>
---
drivers/md/md-llbitmap.c | 24 ++++++++++++++++++++++++
1 file changed, 24 insertions(+)
diff --git a/drivers/md/md-llbitmap.c b/drivers/md/md-llbitmap.c
index ae2e87fd5887..11fede1fc79f 100644
--- a/drivers/md/md-llbitmap.c
+++ b/drivers/md/md-llbitmap.c
@@ -1680,6 +1680,29 @@ static void llbitmap_dirty_bits(struct mddev *mddev, unsigned long s,
llbitmap_state_machine(mddev->bitmap, s, e, BitmapActionStartwrite);
}
+static int llbitmap_reshape_can_start(struct mddev *mddev)
+{
+ struct llbitmap *llbitmap = mddev->bitmap;
+ unsigned long chunk;
+ int ret = 0;
+
+ if (!llbitmap)
+ return 0;
+
+ mutex_lock(&mddev->bitmap_info.mutex);
+ for (chunk = 0; chunk < llbitmap->chunks; chunk++) {
+ enum llbitmap_state state = llbitmap_read(llbitmap, chunk);
+
+ if (state == BitNeedSync || state == BitSyncing) {
+ ret = -EBUSY;
+ break;
+ }
+ }
+ mutex_unlock(&mddev->bitmap_info.mutex);
+
+ return ret;
+}
+
static void llbitmap_reshape_finish(struct mddev *mddev)
{
struct llbitmap *llbitmap = mddev->bitmap;
@@ -2002,6 +2025,7 @@ static struct bitmap_operations llbitmap_ops = {
.dirty_bits = llbitmap_dirty_bits,
.prepare_range = llbitmap_prepare_range,
.reshape_finish = llbitmap_reshape_finish,
+ .reshape_can_start = llbitmap_reshape_can_start,
.write_all = llbitmap_write_all,
.groups = md_llbitmap_groups,
--
2.51.0
^ permalink raw reply related
* [PATCH v2 08/20] md/md-llbitmap: finish reshape geometry
From: Yu Kuai @ 2026-06-24 6:42 UTC (permalink / raw)
To: Song Liu, Yu Kuai; +Cc: Li Nan, Xiao Ni, Su Yue, linux-raid, linux-kernel
In-Reply-To: <cover.1782282042.git.yukuai@kernel.org>
From: Yu Kuai <yukuai@fygo.io>
Commit the staged llbitmap geometry when reshape finishes.
The reshape staging itself is handled through llbitmap_resize(), so only
the finish step remains in this patch.
Signed-off-by: Yu Kuai <yukuai@fygo.io>
---
drivers/md/md-llbitmap.c | 25 +++++++++++++++++++++++++
1 file changed, 25 insertions(+)
diff --git a/drivers/md/md-llbitmap.c b/drivers/md/md-llbitmap.c
index cdced2126e97..ae2e87fd5887 100644
--- a/drivers/md/md-llbitmap.c
+++ b/drivers/md/md-llbitmap.c
@@ -1680,6 +1680,30 @@ static void llbitmap_dirty_bits(struct mddev *mddev, unsigned long s,
llbitmap_state_machine(mddev->bitmap, s, e, BitmapActionStartwrite);
}
+static void llbitmap_reshape_finish(struct mddev *mddev)
+{
+ struct llbitmap *llbitmap = mddev->bitmap;
+
+ if (mddev->pers->quiesce)
+ mddev->pers->quiesce(mddev, 1);
+
+ mutex_lock(&mddev->bitmap_info.mutex);
+ llbitmap_flush(mddev);
+
+ llbitmap->chunksize = llbitmap->reshape_chunksize;
+ llbitmap->chunkshift = ffz(~llbitmap->chunksize);
+ llbitmap->chunks = llbitmap->reshape_chunks;
+ llbitmap->sync_size = llbitmap->reshape_sync_size;
+ llbitmap_refresh_reshape(llbitmap);
+ mddev->bitmap_info.chunksize = llbitmap->chunksize;
+ llbitmap_update_sb(llbitmap);
+ __llbitmap_flush(mddev);
+ mutex_unlock(&mddev->bitmap_info.mutex);
+
+ if (mddev->pers->quiesce)
+ mddev->pers->quiesce(mddev, 0);
+}
+
static void llbitmap_write_sb(struct llbitmap *llbitmap)
{
int nr_blocks = DIV_ROUND_UP(BITMAP_DATA_OFFSET, llbitmap->io_size);
@@ -1977,6 +2001,7 @@ static struct bitmap_operations llbitmap_ops = {
.get_stats = llbitmap_get_stats,
.dirty_bits = llbitmap_dirty_bits,
.prepare_range = llbitmap_prepare_range,
+ .reshape_finish = llbitmap_reshape_finish,
.write_all = llbitmap_write_all,
.groups = md_llbitmap_groups,
--
2.51.0
^ permalink raw reply related
* [PATCH v2 07/20] md/md-llbitmap: track target reshape geometry fields
From: Yu Kuai @ 2026-06-24 6:42 UTC (permalink / raw)
To: Song Liu, Yu Kuai; +Cc: Li Nan, Xiao Ni, Su Yue, linux-raid, linux-kernel
In-Reply-To: <cover.1782282042.git.yukuai@kernel.org>
From: Yu Kuai <yukuai@fygo.io>
Track llbitmap bookkeeping for the target reshape geometry while keeping
a single live bitmap instance.
Add the reshape geometry fields, refresh helper, and update the load and
resize paths to keep the target geometry in sync.
Signed-off-by: Yu Kuai <yukuai@fygo.io>
---
drivers/md/md-llbitmap.c | 39 +++++++++++++++++++++++++++++++++++++++
1 file changed, 39 insertions(+)
diff --git a/drivers/md/md-llbitmap.c b/drivers/md/md-llbitmap.c
index 98e7824c7362..cdced2126e97 100644
--- a/drivers/md/md-llbitmap.c
+++ b/drivers/md/md-llbitmap.c
@@ -289,6 +289,9 @@ struct llbitmap {
unsigned long chunks;
/* total number of sectors tracked by current bitmap geometry */
sector_t sync_size;
+ unsigned long reshape_chunksize;
+ unsigned long reshape_chunks;
+ sector_t reshape_sync_size;
unsigned long last_end_sync;
/*
* time in seconds that dirty bits will be cleared if the page is not
@@ -430,6 +433,39 @@ static void llbitmap_calculate_chunks(struct mddev *mddev, sector_t blocks,
}
}
+static bool llbitmap_reshaping(struct llbitmap *llbitmap)
+{
+ return llbitmap->mddev->reshape_position != MaxSector;
+}
+
+static sector_t llbitmap_personality_sync_size(struct llbitmap *llbitmap,
+ bool previous)
+{
+ struct mddev *mddev = llbitmap->mddev;
+
+ if (!llbitmap_reshaping(llbitmap) || !mddev->private || !mddev->pers ||
+ !mddev->pers->bitmap_sync_size)
+ return llbitmap->sync_size;
+ return mddev->pers->bitmap_sync_size(mddev, previous);
+}
+
+static void llbitmap_refresh_reshape(struct llbitmap *llbitmap)
+{
+ unsigned long old_chunks = DIV_ROUND_UP_SECTOR_T(llbitmap->sync_size,
+ llbitmap->chunksize);
+ sector_t blocks = llbitmap_personality_sync_size(llbitmap, false);
+ unsigned long chunksize = llbitmap->chunksize;
+ unsigned long chunks = DIV_ROUND_UP_SECTOR_T(blocks, chunksize);
+
+ llbitmap->reshape_sync_size = blocks;
+ llbitmap->reshape_chunksize = chunksize;
+ llbitmap->reshape_chunks = chunks;
+ llbitmap_calculate_chunks(llbitmap->mddev, blocks,
+ &llbitmap->reshape_chunksize,
+ &llbitmap->reshape_chunks);
+ llbitmap->chunks = max(old_chunks, llbitmap->reshape_chunks);
+}
+
static enum llbitmap_state llbitmap_read(struct llbitmap *llbitmap, loff_t pos)
{
unsigned int idx;
@@ -1029,6 +1065,7 @@ static int llbitmap_init(struct llbitmap *llbitmap)
llbitmap->chunksize = chunksize;
llbitmap->chunks = chunks;
llbitmap->sync_size = blocks;
+ llbitmap_refresh_reshape(llbitmap);
mddev->bitmap_info.daemon_sleep = DEFAULT_DAEMON_SLEEP;
ret = llbitmap_alloc_pages(llbitmap);
@@ -1140,6 +1177,7 @@ static int llbitmap_read_sb(struct llbitmap *llbitmap)
llbitmap->chunks = DIV_ROUND_UP_SECTOR_T(sync_size, chunksize);
llbitmap->chunkshift = ffz(~chunksize);
llbitmap->sync_size = sync_size;
+ llbitmap_refresh_reshape(llbitmap);
ret = llbitmap_alloc_pages(llbitmap);
out_put_page:
@@ -1295,6 +1333,7 @@ static int llbitmap_resize(struct mddev *mddev, sector_t blocks, int chunksize)
mddev->bitmap_info.chunksize = bitmap_chunksize;
llbitmap->chunks = chunks;
llbitmap->sync_size = blocks;
+ llbitmap_refresh_reshape(llbitmap);
llbitmap_update_sb(llbitmap);
}
__llbitmap_flush(mddev);
--
2.51.0
^ permalink raw reply related
* [PATCH v2 06/20] md/md-llbitmap: grow the page cache in place for reshape
From: Yu Kuai @ 2026-06-24 6:42 UTC (permalink / raw)
To: Song Liu, Yu Kuai; +Cc: Li Nan, Xiao Ni, Su Yue, linux-raid, linux-kernel
In-Reply-To: <cover.1782282042.git.yukuai@kernel.org>
From: Yu Kuai <yukuai@fygo.io>
Use the page-control helpers to grow llbitmap's cached pages in place
for resize and later reshape preparation, instead of rebuilding the
whole cache.
Signed-off-by: Yu Kuai <yukuai@fygo.io>
---
drivers/md/md-llbitmap.c | 139 +++++++++++++++++++++++++++++++++++----
1 file changed, 127 insertions(+), 12 deletions(-)
diff --git a/drivers/md/md-llbitmap.c b/drivers/md/md-llbitmap.c
index 4c3fc4b35aff..98e7824c7362 100644
--- a/drivers/md/md-llbitmap.c
+++ b/drivers/md/md-llbitmap.c
@@ -416,6 +416,19 @@ static char state_machine[BitStateCount][BitmapActionCount] = {
};
static void __llbitmap_flush(struct mddev *mddev);
+static void llbitmap_flush(struct mddev *mddev);
+static void llbitmap_update_sb(void *data);
+
+static void llbitmap_calculate_chunks(struct mddev *mddev, sector_t blocks,
+ unsigned long *chunksize,
+ unsigned long *chunks)
+{
+ *chunks = DIV_ROUND_UP_SECTOR_T(blocks, *chunksize);
+ while (*chunks > mddev->bitmap_info.space << SECTOR_SHIFT) {
+ *chunksize = *chunksize << 1;
+ *chunks = DIV_ROUND_UP_SECTOR_T(blocks, *chunksize);
+ }
+}
static enum llbitmap_state llbitmap_read(struct llbitmap *llbitmap, loff_t pos)
{
@@ -655,6 +668,48 @@ static unsigned int llbitmap_reserved_pages(struct llbitmap *llbitmap)
PAGE_SIZE);
}
+static int llbitmap_expand_pages(struct llbitmap *llbitmap,
+ unsigned long chunks)
+{
+ struct llbitmap_page_ctl **pctl;
+ unsigned int old_nr_pages = llbitmap->nr_pages;
+ unsigned int nr_pages = llbitmap_used_pages(llbitmap, chunks);
+ unsigned int i;
+ int ret;
+
+ if (nr_pages <= old_nr_pages)
+ return 0;
+
+ pctl = kcalloc(nr_pages, sizeof(*pctl), GFP_KERNEL);
+ if (!pctl)
+ return -ENOMEM;
+
+ if (llbitmap->pctl)
+ memcpy(pctl, llbitmap->pctl,
+ array_size(old_nr_pages, sizeof(*pctl)));
+
+ for (i = old_nr_pages; i < nr_pages; i++) {
+ pctl[i] = llbitmap_alloc_page_ctl(llbitmap, i);
+ if (IS_ERR(pctl[i]))
+ goto err_alloc_ptr;
+ }
+
+ kfree(llbitmap->pctl);
+ llbitmap->pctl = pctl;
+ llbitmap->nr_pages = nr_pages;
+ return 0;
+
+err_alloc_ptr:
+ ret = PTR_ERR(pctl[i]);
+ while (i-- > old_nr_pages) {
+ __free_page(pctl[i]->page);
+ percpu_ref_exit(&pctl[i]->active);
+ kfree(pctl[i]);
+ }
+ kfree(pctl);
+ return ret;
+}
+
static int llbitmap_alloc_pages(struct llbitmap *llbitmap)
{
unsigned int used_pages = llbitmap_used_pages(llbitmap, llbitmap->chunks);
@@ -730,6 +785,34 @@ static bool llbitmap_zero_all_disks(struct llbitmap *llbitmap)
return true;
}
+static void llbitmap_mark_range(struct llbitmap *llbitmap,
+ unsigned long start,
+ unsigned long end,
+ enum llbitmap_state state)
+{
+ while (start <= end) {
+ llbitmap_write(llbitmap, state, start);
+ start++;
+ }
+}
+
+static int llbitmap_prepare_resize(struct llbitmap *llbitmap,
+ unsigned long old_chunks,
+ unsigned long new_chunks,
+ unsigned long cache_chunks)
+{
+ int ret;
+
+ llbitmap_flush(llbitmap->mddev);
+ ret = llbitmap_expand_pages(llbitmap, cache_chunks);
+ if (ret)
+ return ret;
+ if (new_chunks > old_chunks)
+ llbitmap_mark_range(llbitmap, old_chunks, new_chunks - 1,
+ BitUnwritten);
+ return 0;
+}
+
static void llbitmap_init_state(struct llbitmap *llbitmap)
{
struct mddev *mddev = llbitmap->mddev;
@@ -1026,10 +1109,10 @@ static int llbitmap_read_sb(struct llbitmap *llbitmap)
goto out_put_page;
}
- if (chunksize < DIV_ROUND_UP_SECTOR_T(mddev->resync_max_sectors,
+ if (chunksize < DIV_ROUND_UP_SECTOR_T(sync_size,
mddev->bitmap_info.space << SECTOR_SHIFT)) {
pr_err("md/llbitmap: %s: chunksize too small %lu < %llu / %lu",
- mdname(mddev), chunksize, mddev->resync_max_sectors,
+ mdname(mddev), chunksize, sync_size,
mddev->bitmap_info.space);
goto out_put_page;
}
@@ -1171,24 +1254,56 @@ static int llbitmap_create(struct mddev *mddev)
static int llbitmap_resize(struct mddev *mddev, sector_t blocks, int chunksize)
{
struct llbitmap *llbitmap = mddev->bitmap;
+ sector_t old_blocks = llbitmap->sync_size;
+ unsigned long old_chunks = llbitmap->chunks;
unsigned long chunks;
+ unsigned long cache_chunks;
+ int ret = 0;
+ unsigned long bitmap_chunksize;
+ bool reshape;
if (chunksize == 0)
chunksize = llbitmap->chunksize;
- /* If there is enough space, leave the chunksize unchanged. */
- chunks = DIV_ROUND_UP_SECTOR_T(blocks, chunksize);
- while (chunks > mddev->bitmap_info.space << SECTOR_SHIFT) {
- chunksize = chunksize << 1;
- chunks = DIV_ROUND_UP_SECTOR_T(blocks, chunksize);
- }
+ bitmap_chunksize = chunksize;
+ llbitmap_calculate_chunks(mddev, blocks, &bitmap_chunksize, &chunks);
- llbitmap->chunkshift = ffz(~chunksize);
- llbitmap->chunksize = chunksize;
- llbitmap->chunks = chunks;
- llbitmap->sync_size = blocks;
+ reshape = mddev->delta_disks || mddev->new_level != mddev->level ||
+ mddev->new_layout != mddev->layout ||
+ mddev->new_chunk_sectors != mddev->chunk_sectors;
+ if (!reshape && bitmap_chunksize != llbitmap->chunksize)
+ return -EOPNOTSUPP;
+ if (blocks == old_blocks && chunks == llbitmap->chunks)
+ return 0;
+
+ mutex_lock(&mddev->bitmap_info.mutex);
+ cache_chunks = reshape ? max(old_chunks, chunks) : chunks;
+ ret = llbitmap_prepare_resize(llbitmap, old_chunks, chunks, cache_chunks);
+ if (ret)
+ goto out;
+
+ if (reshape) {
+ llbitmap->reshape_sync_size = blocks;
+ llbitmap->reshape_chunksize = bitmap_chunksize;
+ llbitmap->reshape_chunks = chunks;
+ llbitmap->chunks = max(old_chunks, chunks);
+ } else {
+ if (blocks < old_blocks && chunks < old_chunks)
+ llbitmap_mark_range(llbitmap, chunks, old_chunks - 1,
+ BitUnwritten);
+ mddev->bitmap_info.chunksize = bitmap_chunksize;
+ llbitmap->chunks = chunks;
+ llbitmap->sync_size = blocks;
+ llbitmap_update_sb(llbitmap);
+ }
+ __llbitmap_flush(mddev);
+ mutex_unlock(&mddev->bitmap_info.mutex);
return 0;
+
+out:
+ mutex_unlock(&mddev->bitmap_info.mutex);
+ return ret;
}
static int llbitmap_load(struct mddev *mddev)
--
2.51.0
^ permalink raw reply related
* [PATCH v2 05/20] md/md-llbitmap: allocate page controls independently
From: Yu Kuai @ 2026-06-24 6:42 UTC (permalink / raw)
To: Song Liu, Yu Kuai; +Cc: Li Nan, Xiao Ni, Su Yue, linux-raid, linux-kernel
In-Reply-To: <cover.1782282042.git.yukuai@kernel.org>
From: Yu Kuai <yukuai@fygo.io>
Allocate one llbitmap page-control object at a time and free each
object through the same model.
Let llbitmap_read_page() return a zeroed page without reading disk when
the page index is beyond the current bitmap size, so page-control
allocation no longer needs a separate read_existing flag.
This keeps the llbitmap page-control lifetime self-consistent and
prepares the page-cache code for later in-place growth.
Signed-off-by: Yu Kuai <yukuai@fygo.io>
Reviewed-by: Su Yue <glass.su@suse.com>
---
drivers/md/md-llbitmap.c | 99 +++++++++++++++++++++++++---------------
1 file changed, 62 insertions(+), 37 deletions(-)
diff --git a/drivers/md/md-llbitmap.c b/drivers/md/md-llbitmap.c
index e3500a1a52c0..4c3fc4b35aff 100644
--- a/drivers/md/md-llbitmap.c
+++ b/drivers/md/md-llbitmap.c
@@ -512,13 +512,19 @@ static void llbitmap_write(struct llbitmap *llbitmap, enum llbitmap_state state,
llbitmap_set_page_dirty(llbitmap, idx, bit, false);
}
+static unsigned int llbitmap_used_pages(struct llbitmap *llbitmap,
+ unsigned long chunks)
+{
+ return DIV_ROUND_UP(chunks + BITMAP_DATA_OFFSET, PAGE_SIZE);
+}
+
static struct page *llbitmap_read_page(struct llbitmap *llbitmap, int idx)
{
struct mddev *mddev = llbitmap->mddev;
struct page *page = NULL;
struct md_rdev *rdev;
- if (llbitmap->pctl && llbitmap->pctl[idx])
+ if (llbitmap->pctl && idx < llbitmap->nr_pages && llbitmap->pctl[idx])
page = llbitmap->pctl[idx]->page;
if (page)
return page;
@@ -526,6 +532,8 @@ static struct page *llbitmap_read_page(struct llbitmap *llbitmap, int idx)
page = alloc_page(GFP_KERNEL | __GFP_ZERO);
if (!page)
return ERR_PTR(-ENOMEM);
+ if (idx >= llbitmap_used_pages(llbitmap, llbitmap->chunks))
+ return page;
rdev_for_each(rdev, mddev) {
sector_t sector;
@@ -596,61 +604,78 @@ static void llbitmap_free_pages(struct llbitmap *llbitmap)
for (i = 0; i < llbitmap->nr_pages; i++) {
struct llbitmap_page_ctl *pctl = llbitmap->pctl[i];
- if (!pctl || !pctl->page)
- break;
-
- __free_page(pctl->page);
+ if (!pctl)
+ continue;
+ if (pctl->page)
+ __free_page(pctl->page);
percpu_ref_exit(&pctl->active);
+ kfree(pctl);
}
- kfree(llbitmap->pctl[0]);
kfree(llbitmap->pctl);
llbitmap->pctl = NULL;
}
-static int llbitmap_cache_pages(struct llbitmap *llbitmap)
+static struct llbitmap_page_ctl *
+llbitmap_alloc_page_ctl(struct llbitmap *llbitmap, int idx)
{
struct llbitmap_page_ctl *pctl;
- unsigned int nr_pages = DIV_ROUND_UP(llbitmap->chunks +
- BITMAP_DATA_OFFSET, PAGE_SIZE);
+ struct page *page;
unsigned int size = struct_size(pctl, dirty, BITS_TO_LONGS(
llbitmap->blocks_per_page));
- int i;
-
- llbitmap->pctl = kmalloc_array(nr_pages, sizeof(void *),
- GFP_KERNEL | __GFP_ZERO);
- if (!llbitmap->pctl)
- return -ENOMEM;
size = round_up(size, cache_line_size());
- pctl = kmalloc_array(nr_pages, size, GFP_KERNEL | __GFP_ZERO);
- if (!pctl) {
- kfree(llbitmap->pctl);
- return -ENOMEM;
+ pctl = kzalloc(size, GFP_KERNEL);
+ if (!pctl)
+ return ERR_PTR(-ENOMEM);
+
+ page = llbitmap_read_page(llbitmap, idx);
+
+ if (IS_ERR(page)) {
+ kfree(pctl);
+ return ERR_CAST(page);
}
- llbitmap->nr_pages = nr_pages;
+ if (percpu_ref_init(&pctl->active, active_release,
+ PERCPU_REF_ALLOW_REINIT, GFP_KERNEL)) {
+ __free_page(page);
+ kfree(pctl);
+ return ERR_PTR(-ENOMEM);
+ }
- for (i = 0; i < nr_pages; i++, pctl = (void *)pctl + size) {
- struct page *page = llbitmap_read_page(llbitmap, i);
+ pctl->page = page;
+ pctl->state = page_address(page);
+ init_waitqueue_head(&pctl->wait);
+ return pctl;
+}
- llbitmap->pctl[i] = pctl;
+static unsigned int llbitmap_reserved_pages(struct llbitmap *llbitmap)
+{
+ return DIV_ROUND_UP(llbitmap->mddev->bitmap_info.space << SECTOR_SHIFT,
+ PAGE_SIZE);
+}
- if (IS_ERR(page)) {
- llbitmap_free_pages(llbitmap);
- return PTR_ERR(page);
- }
+static int llbitmap_alloc_pages(struct llbitmap *llbitmap)
+{
+ unsigned int used_pages = llbitmap_used_pages(llbitmap, llbitmap->chunks);
+ unsigned int nr_pages = max(used_pages, llbitmap_reserved_pages(llbitmap));
+ int i;
+
+ llbitmap->pctl = kcalloc(nr_pages, sizeof(*llbitmap->pctl), GFP_KERNEL);
+ if (!llbitmap->pctl)
+ return -ENOMEM;
- if (percpu_ref_init(&pctl->active, active_release,
- PERCPU_REF_ALLOW_REINIT, GFP_KERNEL)) {
- __free_page(page);
+ llbitmap->nr_pages = nr_pages;
+
+ for (i = 0; i < nr_pages; i++) {
+ llbitmap->pctl[i] = llbitmap_alloc_page_ctl(llbitmap, i);
+ if (IS_ERR(llbitmap->pctl[i])) {
+ int ret = PTR_ERR(llbitmap->pctl[i]);
+
+ llbitmap->pctl[i] = NULL;
llbitmap_free_pages(llbitmap);
- return -ENOMEM;
+ return ret;
}
-
- pctl->page = page;
- pctl->state = page_address(page);
- init_waitqueue_head(&pctl->wait);
}
return 0;
@@ -923,7 +948,7 @@ static int llbitmap_init(struct llbitmap *llbitmap)
llbitmap->sync_size = blocks;
mddev->bitmap_info.daemon_sleep = DEFAULT_DAEMON_SLEEP;
- ret = llbitmap_cache_pages(llbitmap);
+ ret = llbitmap_alloc_pages(llbitmap);
if (ret)
return ret;
@@ -1032,7 +1057,7 @@ static int llbitmap_read_sb(struct llbitmap *llbitmap)
llbitmap->chunks = DIV_ROUND_UP_SECTOR_T(sync_size, chunksize);
llbitmap->chunkshift = ffz(~chunksize);
llbitmap->sync_size = sync_size;
- ret = llbitmap_cache_pages(llbitmap);
+ ret = llbitmap_alloc_pages(llbitmap);
out_put_page:
__free_page(sb_page);
--
2.51.0
^ permalink raw reply related
* [PATCH v2 04/20] md/md-llbitmap: track bitmap sync_size explicitly
From: Yu Kuai @ 2026-06-24 6:42 UTC (permalink / raw)
To: Song Liu, Yu Kuai; +Cc: Li Nan, Xiao Ni, Su Yue, linux-raid, linux-kernel
In-Reply-To: <cover.1782282042.git.yukuai@kernel.org>
From: Yu Kuai <yukuai@fygo.io>
Track llbitmap's own sync_size instead of always using
mddev->resync_max_sectors directly.
This is the minimal bookkeeping needed before llbitmap can track old
and new reshape geometry independently.
Signed-off-by: Yu Kuai <yukuai@fygo.io>
Reviewed-by: Su Yue <glass.su@suse.com>
---
drivers/md/md-llbitmap.c | 14 ++++++++++++--
1 file changed, 12 insertions(+), 2 deletions(-)
diff --git a/drivers/md/md-llbitmap.c b/drivers/md/md-llbitmap.c
index f0c20afa354e..e3500a1a52c0 100644
--- a/drivers/md/md-llbitmap.c
+++ b/drivers/md/md-llbitmap.c
@@ -287,6 +287,8 @@ struct llbitmap {
unsigned long chunksize;
/* total number of chunks */
unsigned long chunks;
+ /* total number of sectors tracked by current bitmap geometry */
+ sector_t sync_size;
unsigned long last_end_sync;
/*
* time in seconds that dirty bits will be cleared if the page is not
@@ -918,6 +920,7 @@ static int llbitmap_init(struct llbitmap *llbitmap)
llbitmap->chunkshift = ffz(~chunksize);
llbitmap->chunksize = chunksize;
llbitmap->chunks = chunks;
+ llbitmap->sync_size = blocks;
mddev->bitmap_info.daemon_sleep = DEFAULT_DAEMON_SLEEP;
ret = llbitmap_cache_pages(llbitmap);
@@ -938,6 +941,7 @@ static int llbitmap_read_sb(struct llbitmap *llbitmap)
unsigned long daemon_sleep;
unsigned long chunksize;
unsigned long events;
+ sector_t sync_size;
struct page *sb_page;
bitmap_super_t *sb;
int ret = -EINVAL;
@@ -987,6 +991,9 @@ static int llbitmap_read_sb(struct llbitmap *llbitmap)
goto out_put_page;
}
+ sync_size = le64_to_cpu(sb->sync_size);
+ if (!sync_size)
+ sync_size = mddev->resync_max_sectors;
chunksize = le32_to_cpu(sb->chunksize);
if (!is_power_of_2(chunksize)) {
pr_err("md/llbitmap: %s: chunksize not a power of 2",
@@ -1022,8 +1029,9 @@ static int llbitmap_read_sb(struct llbitmap *llbitmap)
llbitmap->barrier_idle = DEFAULT_BARRIER_IDLE;
llbitmap->chunksize = chunksize;
- llbitmap->chunks = DIV_ROUND_UP_SECTOR_T(mddev->resync_max_sectors, chunksize);
+ llbitmap->chunks = DIV_ROUND_UP_SECTOR_T(sync_size, chunksize);
llbitmap->chunkshift = ffz(~chunksize);
+ llbitmap->sync_size = sync_size;
ret = llbitmap_cache_pages(llbitmap);
out_put_page:
@@ -1153,6 +1161,7 @@ static int llbitmap_resize(struct mddev *mddev, sector_t blocks, int chunksize)
llbitmap->chunkshift = ffz(~chunksize);
llbitmap->chunksize = chunksize;
llbitmap->chunks = chunks;
+ llbitmap->sync_size = blocks;
return 0;
}
@@ -1526,7 +1535,7 @@ static void llbitmap_update_sb(void *data)
sb->events = cpu_to_le64(mddev->events);
sb->state = cpu_to_le32(llbitmap->flags);
sb->chunksize = cpu_to_le32(llbitmap->chunksize);
- sb->sync_size = cpu_to_le64(mddev->resync_max_sectors);
+ sb->sync_size = cpu_to_le64(llbitmap->sync_size);
sb->events_cleared = cpu_to_le64(llbitmap->events_cleared);
sb->sectors_reserved = cpu_to_le32(mddev->bitmap_info.space);
sb->daemon_sleep = cpu_to_le32(mddev->bitmap_info.daemon_sleep);
@@ -1544,6 +1553,7 @@ static int llbitmap_get_stats(void *data, struct md_bitmap_stats *stats)
stats->missing_pages = 0;
stats->pages = llbitmap->nr_pages;
stats->file_pages = llbitmap->nr_pages;
+ stats->sync_size = llbitmap->sync_size;
stats->behind_writes = atomic_read(&llbitmap->behind_writes);
stats->behind_wait = wq_has_sleeper(&llbitmap->behind_wait);
--
2.51.0
^ permalink raw reply related
* [PATCH v2 03/20] md: add helper to split bios at reshape offset
From: Yu Kuai @ 2026-06-24 6:42 UTC (permalink / raw)
To: Song Liu, Yu Kuai; +Cc: Li Nan, Xiao Ni, Su Yue, linux-raid, linux-kernel
In-Reply-To: <cover.1782282042.git.yukuai@kernel.org>
From: Yu Kuai <yukuai@fygo.io>
Add mddev_bio_split_at_reshape_offset() so personalities can share
reshape-offset bio splitting instead of open-coding the same helper in
multiple places.
Signed-off-by: Yu Kuai <yukuai@fygo.io>
---
drivers/md/md.c | 39 +++++++++++++++++++++++++++++++++++++++
drivers/md/md.h | 4 ++++
2 files changed, 43 insertions(+)
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 0b59c676f7c0..c18a7f3c27e6 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -9361,6 +9361,45 @@ void md_submit_discard_bio(struct mddev *mddev, struct md_rdev *rdev,
}
EXPORT_SYMBOL_GPL(md_submit_discard_bio);
+struct bio *mddev_bio_split_at_reshape_offset(struct mddev *mddev,
+ struct bio *bio,
+ unsigned int *max_sectors,
+ struct bio_set *bs)
+{
+ sector_t boundary;
+ sector_t start;
+ sector_t end;
+ unsigned int split_sectors;
+
+ split_sectors = bio_sectors(bio);
+ if (max_sectors && *max_sectors && *max_sectors < split_sectors)
+ split_sectors = *max_sectors;
+
+ if (!test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
+ goto split;
+
+ boundary = mddev->reshape_position;
+ start = bio->bi_iter.bi_sector;
+ end = bio_end_sector(bio);
+ if (start >= boundary || end <= boundary)
+ goto split;
+
+ if (boundary - start < split_sectors)
+ split_sectors = boundary - start;
+
+split:
+ if (max_sectors)
+ *max_sectors = split_sectors;
+ if (split_sectors < bio_sectors(bio)) {
+ bio = bio_submit_split_bioset(bio, split_sectors, bs);
+ if (bio)
+ bio->bi_opf |= REQ_NOMERGE;
+ }
+
+ return bio;
+}
+EXPORT_SYMBOL_GPL(mddev_bio_split_at_reshape_offset);
+
static void md_bitmap_prepare_range(struct mddev *mddev, sector_t *offset,
unsigned long *sectors)
{
diff --git a/drivers/md/md.h b/drivers/md/md.h
index 110cf0f8b107..ebfc6da83161 100644
--- a/drivers/md/md.h
+++ b/drivers/md/md.h
@@ -925,6 +925,10 @@ extern void md_error(struct mddev *mddev, struct md_rdev *rdev);
extern void md_finish_reshape(struct mddev *mddev);
void md_submit_discard_bio(struct mddev *mddev, struct md_rdev *rdev,
struct bio *bio, sector_t start, sector_t size);
+struct bio *mddev_bio_split_at_reshape_offset(struct mddev *mddev,
+ struct bio *bio,
+ unsigned int *max_sectors,
+ struct bio_set *bs);
void md_account_bio(struct mddev *mddev, struct bio **bio);
extern bool __must_check md_flush_request(struct mddev *mddev, struct bio *bio);
--
2.51.0
^ permalink raw reply related
* [PATCH v2 02/20] md: skip bitmap accounting for empty write ranges
From: Yu Kuai @ 2026-06-24 6:41 UTC (permalink / raw)
To: Song Liu, Yu Kuai; +Cc: Li Nan, Xiao Ni, Su Yue, linux-raid, linux-kernel
In-Reply-To: <cover.1782282042.git.yukuai@kernel.org>
From: Yu Kuai <yukuai@fygo.io>
mkfs.ext4 can submit zero-sector flush/FUA bios. These bios are WRITE
bios for md_write_start() purposes, but they do not cover any data sector
and must not dirty bitmap bits.
md bitmap accounting currently passes such bios to bitmap start_write().
For llbitmap this reaches llbitmap_start_write() with sectors == 0,
which underflows the end chunk calculation.
The new bitmap prepare_range() hook can also turn a non-empty bio into an
empty bitmap range when the requested sectors are outside the active
bitmap geometry. Treat both cases as not started, so the completion path
will not call end_write() for an empty range.
Signed-off-by: Yu Kuai <yukuai@fygo.io>
---
drivers/md/md.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 3b20a57b8c7e..0b59c676f7c0 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -9376,6 +9376,8 @@ static void md_bitmap_start(struct mddev *mddev,
md_bitmap_prepare_range(mddev, &md_io_clone->offset,
&md_io_clone->sectors);
+ if (!md_io_clone->sectors)
+ return;
fn(mddev, md_io_clone->offset, md_io_clone->sectors);
}
@@ -9396,7 +9398,8 @@ static void md_end_clone_io(struct bio *bio)
struct mddev *mddev = md_io_clone->mddev;
struct completion *reshape_completion = bio->bi_private;
- if (bio_data_dir(orig_bio) == WRITE && md_bitmap_enabled(mddev, false))
+ if (bio_data_dir(orig_bio) == WRITE && md_io_clone->sectors &&
+ md_bitmap_enabled(mddev, false))
md_bitmap_end(mddev, md_io_clone);
if (bio->bi_status && !orig_bio->bi_status)
@@ -9423,10 +9426,12 @@ static void md_clone_bio(struct mddev *mddev, struct bio **bio)
md_io_clone = container_of(clone, struct md_io_clone, bio_clone);
md_io_clone->orig_bio = *bio;
md_io_clone->mddev = mddev;
+ md_io_clone->sectors = 0;
if (blk_queue_io_stat(bdev->bd_disk->queue))
md_io_clone->start_time = bio_start_io_acct(*bio);
- if (bio_data_dir(*bio) == WRITE && md_bitmap_enabled(mddev, false)) {
+ if (bio_data_dir(*bio) == WRITE && bio_sectors(*bio) &&
+ md_bitmap_enabled(mddev, false)) {
md_io_clone->offset = (*bio)->bi_iter.bi_sector;
md_io_clone->sectors = bio_sectors(*bio);
md_io_clone->rw = op_stat_group(bio_op(*bio));
--
2.51.0
^ permalink raw reply related
* [PATCH v2 01/20] md: add exact bitmap mapping and reshape hooks
From: Yu Kuai @ 2026-06-24 6:41 UTC (permalink / raw)
To: Song Liu, Yu Kuai; +Cc: Li Nan, Xiao Ni, Su Yue, linux-raid, linux-kernel
In-Reply-To: <cover.1782282042.git.yukuai@kernel.org>
From: Yu Kuai <yukuai@fygo.io>
Add bitmap mapping and reshape hooks needed by llbitmap reshape
support without teaching md core to account a single bio against
multiple bitmap ranges.
This also adds the old/new bitmap geometry helpers used by
personalities to describe reshape mapping to llbitmap.
Signed-off-by: Yu Kuai <yukuai@fygo.io>
---
drivers/md/md-bitmap.c | 8 ++++++++
drivers/md/md-bitmap.h | 8 ++++++++
drivers/md/md-llbitmap.c | 8 ++++++++
drivers/md/md.c | 12 ++++++++----
drivers/md/md.h | 4 ++++
5 files changed, 36 insertions(+), 4 deletions(-)
diff --git a/drivers/md/md-bitmap.c b/drivers/md/md-bitmap.c
index 0f02e2956398..4c31807e6bcc 100644
--- a/drivers/md/md-bitmap.c
+++ b/drivers/md/md-bitmap.c
@@ -1730,6 +1730,13 @@ static void bitmap_start_write(struct mddev *mddev, sector_t offset,
}
}
+static void bitmap_prepare_range(struct mddev *mddev, sector_t *offset,
+ unsigned long *sectors)
+{
+ if (mddev->pers->bitmap_sector)
+ mddev->pers->bitmap_sector(mddev, offset, sectors);
+}
+
static void bitmap_end_write(struct mddev *mddev, sector_t offset,
unsigned long sectors)
{
@@ -3083,6 +3090,7 @@ static struct bitmap_operations bitmap_ops = {
.flush = bitmap_flush,
.write_all = bitmap_write_all,
.dirty_bits = bitmap_dirty_bits,
+ .prepare_range = bitmap_prepare_range,
.unplug = bitmap_unplug,
.daemon_work = bitmap_daemon_work,
diff --git a/drivers/md/md-bitmap.h b/drivers/md/md-bitmap.h
index f46674bdfeb9..26cd07737aab 100644
--- a/drivers/md/md-bitmap.h
+++ b/drivers/md/md-bitmap.h
@@ -93,6 +93,14 @@ struct bitmap_operations {
void (*write_all)(struct mddev *mddev);
void (*dirty_bits)(struct mddev *mddev, unsigned long s,
unsigned long e);
+ /* Prepare a range for this bitmap implementation. */
+ void (*prepare_range)(struct mddev *mddev,
+ sector_t *offset,
+ unsigned long *sectors);
+ void (*reshape_finish)(struct mddev *mddev);
+ int (*reshape_can_start)(struct mddev *mddev);
+ void (*reshape_mark)(struct mddev *mddev, sector_t old_pos,
+ sector_t new_pos);
void (*unplug)(struct mddev *mddev, bool sync);
void (*daemon_work)(struct mddev *mddev);
diff --git a/drivers/md/md-llbitmap.c b/drivers/md/md-llbitmap.c
index 5a4e2abaa757..f0c20afa354e 100644
--- a/drivers/md/md-llbitmap.c
+++ b/drivers/md/md-llbitmap.c
@@ -1188,6 +1188,13 @@ static void llbitmap_destroy(struct mddev *mddev)
mutex_unlock(&mddev->bitmap_info.mutex);
}
+static void llbitmap_prepare_range(struct mddev *mddev, sector_t *offset,
+ unsigned long *sectors)
+{
+ if (mddev->pers->bitmap_sector)
+ mddev->pers->bitmap_sector(mddev, offset, sectors);
+}
+
static void llbitmap_start_write(struct mddev *mddev, sector_t offset,
unsigned long sectors)
{
@@ -1780,6 +1787,7 @@ static struct bitmap_operations llbitmap_ops = {
.update_sb = llbitmap_update_sb,
.get_stats = llbitmap_get_stats,
.dirty_bits = llbitmap_dirty_bits,
+ .prepare_range = llbitmap_prepare_range,
.write_all = llbitmap_write_all,
.groups = md_llbitmap_groups,
diff --git a/drivers/md/md.c b/drivers/md/md.c
index d1465bcd86c8..3b20a57b8c7e 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -9361,6 +9361,12 @@ void md_submit_discard_bio(struct mddev *mddev, struct md_rdev *rdev,
}
EXPORT_SYMBOL_GPL(md_submit_discard_bio);
+static void md_bitmap_prepare_range(struct mddev *mddev, sector_t *offset,
+ unsigned long *sectors)
+{
+ mddev->bitmap_ops->prepare_range(mddev, offset, sectors);
+}
+
static void md_bitmap_start(struct mddev *mddev,
struct md_io_clone *md_io_clone)
{
@@ -9368,10 +9374,8 @@ static void md_bitmap_start(struct mddev *mddev,
mddev->bitmap_ops->start_discard :
mddev->bitmap_ops->start_write;
- if (mddev->pers->bitmap_sector)
- mddev->pers->bitmap_sector(mddev, &md_io_clone->offset,
- &md_io_clone->sectors);
-
+ md_bitmap_prepare_range(mddev, &md_io_clone->offset,
+ &md_io_clone->sectors);
fn(mddev, md_io_clone->offset, md_io_clone->sectors);
}
diff --git a/drivers/md/md.h b/drivers/md/md.h
index d8daf0f75cbb..110cf0f8b107 100644
--- a/drivers/md/md.h
+++ b/drivers/md/md.h
@@ -798,6 +798,10 @@ struct md_personality
/* convert io ranges from array to bitmap */
void (*bitmap_sector)(struct mddev *mddev, sector_t *offset,
unsigned long *sectors);
+ void (*bitmap_sector_map)(struct mddev *mddev, sector_t *offset,
+ unsigned long *sectors, bool previous);
+ sector_t (*bitmap_sync_size)(struct mddev *mddev, bool previous);
+ sector_t (*bitmap_array_sectors)(struct mddev *mddev, bool previous);
};
struct md_sysfs_entry {
--
2.51.0
^ permalink raw reply related
* [PATCH v2 00/20] md/md-llbitmap: support reshape for RAID10 and RAID5
From: Yu Kuai @ 2026-06-24 6:41 UTC (permalink / raw)
To: Song Liu, Yu Kuai; +Cc: Li Nan, Xiao Ni, Su Yue, linux-raid, linux-kernel
In-Reply-To: <20260605091527.2463539-1-yukuai@kernel.org>
Hi,
This series adds llbitmap support for online reshape in RAID10 and RAID5.
llbitmap has a different set of constraints from the existing bitmap code:
there is one live bitmap instance, each bit state has richer semantics, and
reshape can change the mapping from logical array ranges to bitmap ranges.
The series therefore adds exact bitmap range mapping hooks, tracks old and
new llbitmap geometry during reshape, remaps checkpointed bits as reshape
progresses, and wires the reshape lifecycle into RAID10 and RAID5.
The main rules are:
1. split bios at the reshape position before bitmap accounting, so one bio
is never accounted with mixed old/new geometry;
2. do not skip reshape ranges from stale llbitmap state, because reshape
progress is checkpointed by array metadata;
3. remap llbitmap bits when reshape progress is checkpointed;
4. reject llbitmap reshape if mddev->chunk_sectors shrinks, because the
effective data range represented by existing bitmap bits can shrink.
The first group of patches prepares generic bitmap and llbitmap
infrastructure. The second group wires RAID10. The last group wires RAID5,
including exact old/new stripe mapping.
Changes since v1:
- Add Reviewed-by tags from Su Yue.
- Rename llbitmap_resize_chunks() to llbitmap_calculate_chunks().
- Use an unsigned index in llbitmap_expand_pages() error cleanup.
- Rebase on mdraid/md-7.2, including the mddev_bio_split_at_reshape_offset()
declaration needed by the RAID5 build reported by kernel test robot.
Validation:
* RAID5 llbitmap test:
- created 3-disk RAID5 with --bitmap=lockless
- wrote 96 MiB of random data
- reshaped to 4 disks
- llbitmap bits changed from clean=1024 dirty=1024 to
unwritten=448 clean=1600 dirty=0
- all sync-related llbitmap counters were zero after reshape
- data hash was unchanged after reshape
- replaced one disk, waited for recovery, hash was unchanged
- failed another old disk and verified degraded reads still matched
* RAID10 llbitmap test:
- created 4-disk RAID10 n2 with --bitmap=lockless
- wrote 128 MiB of random data
- reshaped to 6 disks
- llbitmap bits changed from clean=2048 dirty=2048 to
unwritten=2048 clean=4096 dirty=0
- all sync-related llbitmap counters were zero after reshape
- data hash was unchanged after reshape
- replaced one disk, waited for recovery, hash was unchanged
- failed the rebuilt disk's mirror mate and verified degraded reads still
matched
Yu Kuai (20):
md: add exact bitmap mapping and reshape hooks
md: skip bitmap accounting for empty write ranges
md: add helper to split bios at reshape offset
md/md-llbitmap: track bitmap sync_size explicitly
md/md-llbitmap: allocate page controls independently
md/md-llbitmap: grow the page cache in place for reshape
md/md-llbitmap: track target reshape geometry fields
md/md-llbitmap: finish reshape geometry
md/md-llbitmap: refuse reshape while llbitmap still needs sync
md/md-llbitmap: add reshape range mapping helpers
md/md-llbitmap: don't skip reshape ranges from bitmap state
md/md-llbitmap: remap checkpointed bits as reshape progresses
md/md-llbitmap: clamp state-machine walks to tracked bits
md/raid10: reject llbitmap reshape when md chunk shrinks
md/raid10: wire llbitmap reshape lifecycle
md/raid10: split reshape bios before bitmap accounting
md/raid5: add exact old and new llbitmap mapping helpers
md/raid5: reject llbitmap reshape when md chunk shrinks
md/raid5: wire llbitmap reshape lifecycle
md/raid5: split reshape bios before bitmap accounting
drivers/md/md-bitmap.c | 8 +
drivers/md/md-bitmap.h | 8 +
drivers/md/md-llbitmap.c | 619 +++++++++++++++++++++++++++++++++++----
drivers/md/md.c | 60 +++-
drivers/md/md.h | 8 +
drivers/md/raid10.c | 49 ++++
drivers/md/raid5.c | 118 ++++++--
7 files changed, 795 insertions(+), 75 deletions(-)
base-commit: 55b77337bdd088c77461588e5ec094421b89911b
--
2.51.0
^ permalink raw reply
* Re: [PATCH] md/raid1: honor REQ_NOWAIT when waiting for behind writes
From: yu kuai @ 2026-06-24 6:39 UTC (permalink / raw)
To: Abd-Alrhman Masalkhi, song, magiclinan, xiao, vverma, axboe
Cc: linux-raid, linux-kernel, yukuai
In-Reply-To: <m2y0g722bp.fsf@gmail.com>
Hi,
在 2026/6/22 2:08, Abd-Alrhman Masalkhi 写道:
> What if on a partial nowait failure we just end the master bio as
> success, but set NEEDED on that chunk's bitmap counter and start_sync()
> picks it up for resync? That way we don't have to decide why rdev2
> failed at all, resync just copies from rdev1 to rdev2 without nowait,
> so if it's a real bad block, end_sync_write() records it then.
>
> We kinda have the idea of ending the bio before the write lands on all
> mirrors in write-behind already, though it's not quite the same, there
> the deferred write still lands, here we ACK after it already failed and
> lean on resync to redo it.
>
> My worry is the loaded case: AGAIN under queue pressure isn't that rare,
> so we might end up triggering resync frequently. Do you think that's
> acceptable, or is dropping nowait better? Happy to prototype either way.
Yes, AGAIN under queue pressure isn't rare, and I don't think trigger resync
for a nowait IO failure is acceptable. This can cause lots of offline IO
pressure which will affect disk service life. Meanwhile, resync will cause
performance degradation for user.
I still feel dropping nowait is better.
--
Thanks,
Kuai
^ permalink raw reply
* Re: [PATCH v6 2/3] md/raid10: resize r10bio_pool for reshape
From: Chen Cheng @ 2026-06-24 6:32 UTC (permalink / raw)
To: sashiko-reviews; +Cc: yukuai, linux-raid
In-Reply-To: <20260623130100.477FE1F000E9@smtp.kernel.org>
在 2026/6/23 21:00, sashiko-bot@kernel.org 写道:
> Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
> - [Medium] The newly allocated `new_pool` is leaked on the `reshape_backwards` error path.
> --
>
> commit 2142096170ffdd8a1caabfde6f2461f6e7d64f61
> Author: Chen Cheng <chencheng@fnnas.com>
>
> md/raid10: resize r10bio_pool for reshape
>
> When reshape grows raid_disks, the pool must also switch to new geometry
> object size, and allocate a new geometry size pool and replace the old.
>
> But not for shrinking reshape, because regular I/O can still use the
> prev geo for sectors that have not crossed reshape_progress yet.
>
>> diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
>> index cee5a253a281d..d740744a97461 100644
>> --- a/drivers/md/raid10.c
>> +++ b/drivers/md/raid10.c
> [ ... ]
>> @@ -4411,6 +4422,11 @@ static int raid10_start_reshape(struct mddev *mddev)
>> return -EINVAL;
>>
>> conf->offset_diff = min_offset_diff;
>> + if (mddev->delta_disks > 0) {
>> + new_pool = create_r10bio_pool(new.raid_disks);
>> + if (!new_pool)
>> + return -ENOMEM;
>> + }
>> spin_lock_irq(&conf->device_lock);
>> if (conf->mirrors_new) {
>> memcpy(conf->mirrors_new, conf->mirrors,
>
> [Severity: Medium]
> Will this newly allocated new_pool be leaked if the reshape_backwards
> error path is triggered?
>
> If an array is configured for a reshape that expands the number of disks
> (delta_disks > 0), the new_pool is allocated here. However, if the
> component device sizes are also reduced such that the array is set to
> reshape backwards, it can hit a pre-existing error check a few lines
> down:
It's impossible use backward reshape while delta disk > 0 or change
component size.
>
> if (mddev->reshape_backwards) {
> sector_t size = raid10_size(mddev, 0, 0);
> if (size < mddev->array_sectors) {
> spin_unlock_irq(&conf->device_lock);
> pr_warn("md/raid10:%s: array size must be reduce before number of disks\n",
> mdname(mddev));
> return -EINVAL;
> }
>
> This direct return skips the standard cleanup path at the abort label,
> causing the mempool_t structure and its preallocated elements to leak.
> Should we add a mempool_destroy(new_pool) here, or change the return to
> a goto abort?
>
^ permalink raw reply
* Re: [PATCH v2] md/raid5-ppl: fix use-after-free in ppl_do_flush()
From: Brigham Campbell @ 2026-06-24 4:42 UTC (permalink / raw)
To: Sajal Gupta, linux-raid, song
Cc: yukuai3, tomasz.majchrzak, linux-kernel, error27, skhan, me,
linux-kernel-mentees
In-Reply-To: <20260622142146.56637-1-sajal2005gupta@gmail.com>
On Mon Jun 22, 2026 at 8:06 AM MDT, Sajal Gupta wrote:
> Compile tested only.
It looks like you're on the right track, but this could use some
testing. My analysis here may be incorrect, but it looks like it should
be pretty easy to test this patch by compiling and running on a system
with a RAID5 array, PPL enabled, and no RAID journal. I expect the call
stack would look something like the following (feel free to correct me,
anyone...):
ppl_do_flush
ppl_stripe_write_finished
log_stripe_write_finished
handle_stripe
...
To be sure, you can add a tracepoint[^1] inside ppl_do_flush.
Dan was probably reluctant to make the change himself, opting to instead
submit a KTODO because the change is relatively straightforward, but
testing is a little more involved. Testing is particularly important
with respect to subsystems pertaining to the filesystem because latent
regressions could mean permanent data loss.
Cheers,
Brigham
[1]: https://docs.kernel.org/trace/tracepoints.html
^ permalink raw reply
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