Re: [RFC] Re: broken userland ABI in configfs binary attributes

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Mon, Aug 26, 2019 at 05:29:49PM +0100, Al Viro wrote:
> On Mon, Aug 26, 2019 at 03:48:38AM +0100, Al Viro wrote:
> 
> > 	We might be able to paper over that mess by doing what /dev/st does -
> > checking that file_count(file) == 1 in ->flush() instance and doing commit
> > there in such case.  It's not entirely reliable, though, and it's definitely
> > not something I'd like to see spreading.
> 
> 	This "not entirely reliable" turns out to be an understatement.
> If you have /proc/*/fdinfo/* being read from at the time of final close(2),
> you'll get file_count(file) > 1 the last time ->flush() is called.  In other
> words, we'd get the data not committed at all.

How about always doing the write in ->flush instead of ->release?
Yes, that means that calling close(dup(fd)) is going to flush the
write, but you shouldn't be doing that.  I think there'll also be
extra flushes done if you fork() during one of these writes ... but,
again, don't do that.  It's not like these are common things.

Why does the prototype of file_operations::release suggest that it can
return an int?  __fput doesn't pay any attention to the return value.
Changing that to return void might help some future programmers avoid
this mistake.



[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Index of Archives]     [SCSI Target Devel]     [Linux SCSI Target Infrastructure]     [Kernel Newbies]     [IDE]     [Security]     [Git]     [Netfilter]     [Bugtraq]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Linux ATA RAID]     [Linux IIO]     [Samba]     [Device Mapper]

  Powered by Linux