From 3a84e55858171f96321fa4c775fe7e4e851c6b85 Mon Sep 17 00:00:00 2001 From: Heming Zhao Date: Thu, 31 Mar 2022 23:30:51 +0800 Subject: [PATCH] mdadm/super1: restore commit 45a87c2f31335 to fix clustered slot issue To: linux-raid@vger.kernel.org, jes@trained-monkey.org Patch-mainline: N/A, maintainer didn't respond this patch. References: bsc#1197158, bsc#1197571 Commit 9d67f6496c71 ("mdadm:check the nodes when operate clustered array") modified assignment logic for st->nodes in write_bitmap1(), which introduced bitmap slot issue: load_super1 didn't set up supertype.nodes, which made spare disk only have one slot info. Then it triggered kernel md_bitmap_load_sb to get wrong bitmap slot data. For fixing this issue, there are two methods: 1> revert the related code of commit 9d67f6496c71. and restore the code from former commit 45a87c2f31335 ("super1: add more checks for NodeNumUpdate option"). st->nodes value would be 0 & 1 under current code logic. i.e. When adding a spare disk, there is no place to init st->nodes, and the value is ZERO. 2> keep 9d67f6496c71, add additional ->nodes handling in load_super1(), let load_super1 to set st->nodes when bitmap is BITMAP_MAJOR_CLUSTERED. Under current mdadm code logic, load_super1 will be called many times, any new code in load_super1 will cost mdadm running more time. And more reason is I prefer as much as possible to limit clustered code spreading in every corner. So I used method <1> to fix this issue. How to trigger: dd if=/dev/zero bs=1M count=1 oflag=direct of=/dev/sda dd if=/dev/zero bs=1M count=1 oflag=direct of=/dev/sdb dd if=/dev/zero bs=1M count=1 oflag=direct of=/dev/sdc mdadm -C /dev/md0 -b clustered -e 1.2 -n 2 -l mirror /dev/sda /dev/sdb mdadm -a /dev/md0 /dev/sdc mdadm /dev/md0 --fail /dev/sda mdadm /dev/md0 --remove /dev/sda mdadm -Ss mdadm -A /dev/md0 /dev/sdb /dev/sdc the output of current "mdadm -X /dev/sdc": (there should be (by default) 4 slot info for correct output) ``` Filename : /dev/sdc Magic : 6d746962 Version : 5 UUID : a74642f8:a6b1fba8:58e1f8db:cfe7b082 Events : 29 Events Cleared : 0 State : OK Chunksize : 64 MB Daemon : 5s flush period Write Mode : Normal Sync Size : 306176 (299.00 MiB 313.52 MB) Bitmap : 5 bits (chunks), 5 dirty (100.0%) ``` And mdadm later operations will trigger kernel output error message: (triggered by "mdadm -A /dev/md0 /dev/sdb /dev/sdc") ``` kernel: md0: invalid bitmap file superblock: bad magic kernel: md_bitmap_copy_from_slot can't get bitmap from slot 1 kernel: md-cluster: Could not gather bitmaps from slot 1 kernel: md0: invalid bitmap file superblock: bad magic kernel: md_bitmap_copy_from_slot can't get bitmap from slot 2 kernel: md-cluster: Could not gather bitmaps from slot 2 kernel: md0: invalid bitmap file superblock: bad magic kernel: md_bitmap_copy_from_slot can't get bitmap from slot 3 kernel: md-cluster: Could not gather bitmaps from slot 3 kernel: md-cluster: failed to gather all resyn infos kernel: md0: detected capacity change from 0 to 612352 ``` Acked-by: Coly Li Signed-off-by: Heming Zhao --- super1.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/super1.c b/super1.c index a12a5bc847b9..f08d4f831319 100644 --- a/super1.c +++ b/super1.c @@ -2674,7 +2674,17 @@ static int write_bitmap1(struct supertype *st, int fd, enum bitmap_update update } if (bms->version == BITMAP_MAJOR_CLUSTERED) { - if (__cpu_to_le32(st->nodes) < bms->nodes) { + if (st->nodes == 1) { + /* the parameter for nodes is not valid */ + pr_err("Warning: cluster-md at least needs two nodes\n"); + return -EINVAL; + } else if (st->nodes == 0) { + /* + * parameter "--nodes" is not specified, (eg, add a disk to + * clustered raid) + */ + break; + } else if (__cpu_to_le32(st->nodes) < bms->nodes) { /* * Since the nodes num is not increased, no * need to check the space enough or not, -- 2.33.0