From: Alan Stern <[EMAIL PROTECTED]>
> On
Fri,
15
Feb
2008,
tike64
wrote:
>>
I
have
an
annoying
problem:
When
I
have
an
USB
memory
stick
attached
>>
and
then
detach
it
while
I
have
a
file
open
on
it,
the
device
node
is
>>
left
reserved
even
if
it
disappears
from
the
/dev
dir.
If
the
device
>>
node
was
/dev/sda
then
next
time
it
would
be
/dev/sdb.
Additional
>>
symptom
is
that
the
related
scsi_eh_?
process
doesn't
die.
>> ...
> It
isn't
a
problem
at
all;
it
is
the
desired
behavior.
As
long
as
the
> file
remains
open,
the
kernel
has
to
maintain
the
device
node
> (internally
if
not
externally)
and
the
SCSI
error-handler
process.
> Thus
the
node
name
is
not
available
for
new
devices
to
use.
But I'm pretty sure the device node remains reserved even after closing the
file and that is the problem.
> ...
>>
Is
there
some
kind
of
workaround?
>
> Yes
indeed:
Close
the
open
files
and
unmount
the
filesystem
before
> unplugging
the
memory
stick.
This
is
just
good
practice
in
any
case;
> if
you
don't
follow
it
then
you
risk
losing
data.
Yes the risk losing data is obvious but leaking system resources is simply
wrong. In real life in 24/7 system it is bound to happen that the user detaches
the stick at wrong moment. Data loss can be fixed by asking the user to put the
stick back. But if the system resources are leaking it means eventually a need
for rebooting and that is wrong. My ubuntu desktop system doesn't have this
problem and that tells me that the problem is introduced by the older kernel
version, ARM environment or the buildroot generated user space.
--
Timo
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