Re: [PATCH v4 1/4] md: Don't clear MD_CLOSING when the raid is about to stop
From: Yu Kuai <hidden>
Date: 2024-01-27 08:38:08
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Hi, 在 2024/01/26 17:22, linan666@huaweicloud.com 写道:
From: Li Nan <redacted> The raid should not be opened anymore when it is about to be stopped. However, other processes can open it again if the flag MD_CLOSING is cleared before exiting. From now on, this flag will not be cleared when the raid will be stopped.
This patch looks good, just one nit below:
quoted hunk ↗ jump to hunk
Fixes: 065e519e71b2 ("md: MD_CLOSING needs to be cleared after called md_set_readonly or do_md_stop") Signed-off-by: Li Nan <redacted> Acked-by: Mariusz Tkaczyk <redacted> --- drivers/md/md.c | 22 ++++++++++++++++++---- 1 file changed, 18 insertions(+), 4 deletions(-)diff --git a/drivers/md/md.c b/drivers/md/md.c index 9bdd57324c37..06550fe34aa1 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c@@ -6254,7 +6254,15 @@ static void md_clean(struct mddev *mddev) mddev->persistent = 0; mddev->level = LEVEL_NONE; mddev->clevel[0] = 0; - mddev->flags = 0; + /* + * Don't clear MD_CLOSING, or mddev can be opened again. + * 'hold_active != 0' means mddev is still in the creation + * process and will be used later. + */ + if (mddev->hold_active) + mddev->flags = 0; + else + mddev->flags &= BIT_ULL_MASK(MD_CLOSING); mddev->sb_flags = 0; mddev->ro = MD_RDWR; mddev->metadata_type[0] = 0;@@ -7600,7 +7608,7 @@ static int md_ioctl(struct block_device *bdev, blk_mode_t mode, int err = 0; void __user *argp = (void __user *)arg; struct mddev *mddev = NULL; - bool did_set_md_closing = false; + bool clear_md_closing = false; if (!md_ioctl_valid(cmd)) return -ENOTTY;@@ -7684,7 +7692,7 @@ static int md_ioctl(struct block_device *bdev, blk_mode_t mode, err = -EBUSY; goto out; } - did_set_md_closing = true; + clear_md_closing = true; mutex_unlock(&mddev->open_mutex); sync_blockdev(bdev); }@@ -7728,6 +7736,12 @@ static int md_ioctl(struct block_device *bdev, blk_mode_t mode, case STOP_ARRAY: err = do_md_stop(mddev, 0, bdev); + if (!err) + /* + * mddev has been stopped, keep the flag + * MD_CLOSING to prevent reuse. + */ + clear_md_closing = false; goto unlock; case STOP_ARRAY_RO:@@ -7826,7 +7840,7 @@ static int md_ioctl(struct block_device *bdev, blk_mode_t mode, mddev_unlock(mddev); out: - if(did_set_md_closing) + if (clear_md_closing)
I think code will be simplier if we just remove this local variable, and replace this with: if (test_bit(MD_CLOSING, &mddev->flags) && (err || cmd == STOP_ARRAY_RO)) And the same for patch 3. Thanks, Kuai
clear_bit(MD_CLOSING, &mddev->flags); return err; }