[Libguestfs] [PATCH v2] NEW API: add blkid command to print the attributes of the device

[Richard W.M. Jones]

On Sun, Dec 04, 2011 at 11:18:37AM +0800, Wanlong Gao wrote:
> Hi Rich:
> 
> > 
> > ACKed and pushed,
> > 
> > Thanks!
> > 
> > Rich.
> > 
> 
> 
> I saw that you killed the '-p' option because RHEL5 didn't support this,
> I want to know that which version of blkid you use? or which util-linux?
> or which RHEL5 updated release?
>
> Because in my RHEL5.7GA, the '-i' option isn't supported, either.

Yup, you're right ...

For '-p': '-c /dev/null' should be completely equivalent and it's what
we use in the rest of daemon/blkid.c.  Is there any other benefit to
using '-p' instead of '-c /dev/null'?

Obviously I didn't test this, which is why I didn't see that the '-i'
option isn't supported on RHEL 5 ...

> But does the '-i' option supported on RHEL5.8?

I'll need to add a test for it.  It seems pretty straightforward just
comparing the blkid --help output on RHEL 5:

  $ /sbin/blkid --help
  /sbin/blkid: invalid option -- -
  blkid 1.0.0 (12-Feb-2003)
  usage:	    blkid [-c <file>] [-ghl] [-o format] [-s <tag>] [-t <token>]
      [-v] [-w <file>] [dev ...]
      -c	 cache file (default: /etc/blkid/blkid.tab, /dev/null = none)
      -g	 garbage collect the blkid cache
      -h	 print this usage message and exit
      -s	 show specified tag(s) (default show all tags)
      -t	 find device with a specific token (NAME=value pair)
      -l	 lookup the the first device with arguments specified by -t
      -v	 print version and exit
      -w	 write cache to different file (/dev/null = no write)
      dev	 specify device(s) to probe (default: all devices)

versus upstream:

  $ blkid --help
  blkid: invalid option -- '-'
  blkid from util-linux 2.20.1 (libblkid 2.20.0, 19-Oct-2011)
  Usage:
  [...]
   -p          low-level superblocks probing (bypass cache)
   -i          gather information about I/O limits

It is sufficient to grep the blkid --help stderr for '-i'.

> I saw that the latest e2fsprogs also don't support the '-p' and '-i'
> options, So I'm considering add these options into e2fsprogs, is it
> needed?

Which e2fsprogs program do you mean?

Rich.

-- 
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