linux-stable.git/drivers/md/md-bitmap.c, branch v6.16.2

md/md-bitmap: fix GPF in bitmap_get_stats()

2025-07-05T11:36:50+00:00

The commit message of commit 6ec1f0239485 ("md/md-bitmap: fix stats
collection for external bitmaps") states:

    Remove the external bitmap check as the statistics should be
    available regardless of bitmap storage location.

    Return -EINVAL only for invalid bitmap with no storage (neither in
    superblock nor in external file).

But, the code does not adhere to the above, as it does only check for
a valid super-block for "internal" bitmaps. Hence, we observe:

Oops: GPF, probably for non-canonical address 0x1cd66f1f40000028
RIP: 0010:bitmap_get_stats+0x45/0xd0
Call Trace:

 seq_read_iter+0x2b9/0x46a
 seq_read+0x12f/0x180
 proc_reg_read+0x57/0xb0
 vfs_read+0xf6/0x380
 ksys_read+0x6d/0xf0
 do_syscall_64+0x8c/0x1b0
 entry_SYSCALL_64_after_hwframe+0x76/0x7e

We fix this by checking the existence of a super-block for both the
internal and external case.

Fixes: 6ec1f0239485 ("md/md-bitmap: fix stats collection for external bitmaps")
Cc: stable@vger.kernel.org
Reported-by: Gerald Gibson 
Signed-off-by: Håkon Bugge 
Link: https://lore.kernel.org/linux-raid/20250702091035.2061312-1-haakon.bugge@oracle.com
Signed-off-by: Yu Kuai

md/md-bitmap: remove parameter slot from bitmap_create()

2025-05-30T07:47:23+00:00

All callers pass in '-1' for 'slot', hence it can be removed.

Link: https://lore.kernel.org/linux-raid/20250524061320.370630-6-yukuai1@huaweicloud.com
Signed-off-by: Yu Kuai 
Reviewed-by: Christoph Hellwig 
Reviewed-by: Xiao Ni 
Reviewed-by: Christoph Hellwig 
Reviewed-by: Hannes Reinecke

md/md-bitmap: cleanup bitmap_ops->startwrite()

2025-05-30T07:47:23+00:00

bitmap_startwrite() always return 0, and the caller doesn't check return
value as well, hence change the method to void.

Also rename startwrite/endwrite to start_write/end_write, which is more in
line with the usual naming convention.

Link: https://lore.kernel.org/linux-raid/20250524061320.370630-4-yukuai1@huaweicloud.com
Signed-off-by: Yu Kuai 
Reviewed-by: Xiao Ni 
Reviewed-by: Christoph Hellwig 
Reviewed-by: Hannes Reinecke

md/dm-raid: remove max_write_behind setting limit

2025-05-30T07:47:23+00:00

The comments said 'vaule in kB', while the value actually means the
number of write_behind IOs. And since md-bitmap will automatically
adjust the value to max COUNTER_MAX / 2, there is no need to fail
early.

Also move some macros that is only used md-bitmap.c.

Link: https://lore.kernel.org/linux-raid/20250524061320.370630-15-yukuai1@huaweicloud.com
Signed-off-by: Yu Kuai 
Reviewed-by: Christoph Hellwig 
Reviewed-by: Hannes Reinecke 
Reviewed-by: Xiao Ni

md/md-bitmap: fix dm-raid max_write_behind setting

2025-05-30T07:47:23+00:00

It's supposed to be COUNTER_MAX / 2, not COUNTER_MAX.

Link: https://lore.kernel.org/linux-raid/20250524061320.370630-14-yukuai1@huaweicloud.com
Signed-off-by: Yu Kuai 
Reviewed-by: Christoph Hellwig 
Reviewed-by: Hannes Reinecke

md/md-bitmap: fix stats collection for external bitmaps

2025-04-06T04:55:13+00:00

The bitmap_get_stats() function incorrectly returns -ENOENT for external
bitmaps.

Remove the external bitmap check as the statistics should be available
regardless of bitmap storage location.

Return -EINVAL only for invalid bitmap with no storage (neither in
superblock nor in external file).

Note: "bitmap_info.external" here refers to a bitmap stored in a separate
file (bitmap_file), not to external metadata.

Fixes: 8d28d0ddb986 ("md/md-bitmap: Synchronize bitmap_get_stats() with bitmap lifetime")
Signed-off-by: Zheng Qixing 
Link: https://lore.kernel.org/linux-raid/20250403015322.2873369-1-zhengqixing@huaweicloud.com
Signed-off-by: Yu Kuai

md/md-bitmap: fix wrong bitmap_limit for clustermd when write sb

2025-03-04T16:34:00+00:00

In clustermd, separate write-intent-bitmaps are used for each cluster
node:

0                    4k                     8k                    12k
-------------------------------------------------------------------
| idle                | md super            | bm super [0] + bits |
| bm bits[0, contd]   | bm super[1] + bits  | bm bits[1, contd]   |
| bm super[2] + bits  | bm bits [2, contd]  | bm super[3] + bits  |
| bm bits [3, contd]  |                     |                     |

So in node 1, pg_index in __write_sb_page() could equal to
bitmap->storage.file_pages. Then bitmap_limit will be calculated to
0. md_super_write() will be called with 0 size.
That means the first 4k sb area of node 1 will never be updated
through filemap_write_page().
This bug causes hang of mdadm/clustermd_tests/01r1_Grow_resize.

Here use (pg_index % bitmap->storage.file_pages) to make calculation
of bitmap_limit correct.

Fixes: ab99a87542f1 ("md/md-bitmap: fix writing non bitmap pages")
Signed-off-by: Su Yue 
Reviewed-by: Heming Zhao 
Link: https://lore.kernel.org/linux-raid/20250303033918.32136-1-glass.su@suse.com
Signed-off-by: Yu Kuai

md: don't export md_cluster_ops

2025-03-04T16:28:17+00:00

Add a new field 'cluster_ops' and initialize it md_setup_cluster(), so
that the gloable variable 'md_cluter_ops' doesn't need to be exported.
Also prepare to switch md-cluster to use md_submod_head.

Link: https://lore.kernel.org/linux-raid/20250215092225.2427977-7-yukuai1@huaweicloud.com
Signed-off-by: Yu Kuai 
Reviewed-by: Su Yue

md: only include md-cluster.h if necessary

2025-03-04T16:26:21+00:00

md-cluster is only supportted by raid1 and raid10, there is no need to
include md-cluster.h for other personalities.

Also move APIs that is only used in md-cluster.c from md.h to
md-cluster.h.

Link: https://lore.kernel.org/linux-raid/20250215092225.2427977-3-yukuai1@huaweicloud.com
Signed-off-by: Yu Kuai 
Reviewed-by: Su Yue

md/md-bitmap: Synchronize bitmap_get_stats() with bitmap lifetime

2025-01-24T18:03:32+00:00

After commit ec6bb299c7c3 ("md/md-bitmap: add 'sync_size' into struct
md_bitmap_stats"), following panic is reported:

Oops: general protection fault, probably for non-canonical address
RIP: 0010:bitmap_get_stats+0x2b/0xa0
Call Trace:
 
 md_seq_show+0x2d2/0x5b0
 seq_read_iter+0x2b9/0x470
 seq_read+0x12f/0x180
 proc_reg_read+0x57/0xb0
 vfs_read+0xf6/0x380
 ksys_read+0x6c/0xf0
 do_syscall_64+0x82/0x170
 entry_SYSCALL_64_after_hwframe+0x76/0x7e

Root cause is that bitmap_get_stats() can be called at anytime if mddev
is still there, even if bitmap is destroyed, or not fully initialized.
Deferenceing bitmap in this case can crash the kernel. Meanwhile, the
above commit start to deferencing bitmap->storage, make the problem
easier to trigger.

Fix the problem by protecting bitmap_get_stats() with bitmap_info.mutex.

Cc: stable@vger.kernel.org # v6.12+
Fixes: 32a7627cf3a3 ("[PATCH] md: optimised resync using Bitmap based intent logging")
Reported-and-tested-by: Harshit Mogalapalli 
Closes: https://lore.kernel.org/linux-raid/ca3a91a2-50ae-4f68-b317-abd9889f3907@oracle.com/T/#m6e5086c95201135e4941fe38f9efa76daf9666c5
Signed-off-by: Yu Kuai 
Link: https://lore.kernel.org/r/20250124092055.4050195-1-yukuai1@huaweicloud.com
Signed-off-by: Song Liu