Re: [patch 1/1] Drop CAP_SYS_RAWIO requirement for FIBMAP

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

 




Pavel Machek wrote:
Hi!

Remove the need for having CAP_SYS_RAWIO when doing a FIBMAP call on an open file descriptor.

It would be nice to allow users to have permission to see where their data is landing on disk, and there really isn't a good reason to keep them from getting at this information.

I believe it is to prevent users from intentionally creating extremely
fragmented files...

You can read 60MB in a second, but fragmented 60MB file could take
10msec * 60MB/4KB = 150 seconds. That's factor 150 slowdown...

...but I agree that SYS_RAWIO may be wrong capability to cover this.

							Pavel

I don't see how restricting FIBMAP use helps prevent fragmentation since FIBMAP just allows you to see what damage was already done.

You can create nicely fragmented files simply by having multiple threads writing concurrently to one or more files in the same directory (depending on the file system, allocation policy, etc).

ric

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[Index of Archives]     [Kernel Newbies]     [Netfilter]     [Bugtraq]     [Photo]     [Stuff]     [Gimp]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Video 4 Linux]     [Linux for the blind]     [Linux Resources]
  Powered by Linux