From mboxrd@z Thu Jan  1 00:00:00 1970
From: Spelic <spelic@shiftmail.org>
Subject: Re: mdadm incremental failed: md device busy
Date: Wed, 15 Dec 2010 19:50:46 +0100
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On 12/15/2010 06:50 PM, Spelic wrote:
> Hi there
> this happened:
>
> # cat /proc/mdstat
> ...other arrays not including sdb3...
> md2 : active raid1 sda3[0]
>       52428728 blocks super 1.2 [2/1] [U_]
>       bitmap: 6/200 pages [24KB], 128KB chunk
> ...other arrays not including sdb3...
>
> strangely sdb3 was not added to array at boot, I am still 
> investigating that, but now see this:
>
> # mdadm --incremental /dev/sdb3
> mdadm: failed to open /dev/md2: Device or resource busy.
>
>
> #strace mdadm --incremental /dev/sdb3
> ...lots of stuff, then...
> open("/dev/md2", O_RDWR|O_EXCL)         = -1 EBUSY (Device or resource 
> busy)
> nanosleep({0, 200000000}, NULL)         = 0
> open("/dev/md2", O_RDWR|O_EXCL)         = -1 EBUSY (Device or resource 
> busy)
> nanosleep({0, 200000000}, NULL)         = 0
> open("/dev/md2", O_RDWR|O_EXCL)         = -1 EBUSY (Device or resource 
> busy)
> nanosleep({0, 200000000}, NULL)         = 0
> open("/dev/md2", O_RDWR|O_EXCL)         = -1 EBUSY (Device or resource 
> busy)
> nanosleep({0, 200000000}, NULL)         = 0
> open("/dev/md2", O_RDWR|O_EXCL)         = -1 EBUSY (Device or resource 
> busy)
> nanosleep({0, 200000000}, NULL)         = 0
> open("/dev/md2", O_RDWR|O_EXCL)         = -1 EBUSY (Device or resource 
> busy)
> nanosleep({0, 200000000}, NULL)         = 0
> open("/dev/md2", O_RDWR|O_EXCL)         = -1 EBUSY (Device or resource 
> busy)
> nanosleep({0, 200000000}, NULL)         = 0
> open("/dev/md2", O_RDWR|O_EXCL)         = -1 EBUSY (Device or resource 
> busy)
> nanosleep({0, 200000000}, NULL)         = 0
> open("/dev/md2", O_RDWR|O_EXCL)         = -1 EBUSY (Device or resource 
> busy)
> nanosleep({0, 200000000}, NULL)         = 0
> open("/dev/md2", O_RDWR|O_EXCL)         = -1 EBUSY (Device or resource 
> busy)
> nanosleep({0, 200000000}, NULL)         = 0
> open("/dev/md2", O_RDWR|O_EXCL)         = -1 EBUSY (Device or resource 
> busy)
> nanosleep({0, 200000000}, NULL)         = 0
> open("/dev/md2", O_RDWR|O_EXCL)         = -1 EBUSY (Device or resource 
> busy)
> ........
> write(2, "mdadm: failed to open /dev/md2: "..., 57mdadm: failed to 
> open /dev/md2: Device or resource busy.
> ) = 57
>
>
> hmmm... strange thing, I just booted and md2 is not even mounted...
> but now see this:
>
> # mdadm /dev/md2 --add /dev/sdb3
> mdadm: re-added /dev/sdb3
>
> worked perfectly!
>
> So?
> Bug?
>
> Thank you

I add one detail: the drive probably had been kicked at boot because it 
was non-fresh.