[PATCH] xfs_showargs() reports group *and* project quotas enabled

[Felix Blyakher]

On Aug 26, 2009, at 12:46 PM, Alex Elder wrote:

> If you enable group or project quotas on an XFS file system, then the
> mount table presented through /proc/self/mounts erroneously shows
> that both options are in effect for the file system.  The root of
> the problem is some bad logic in the xfs_showargs() function, which
> is used to format the file system type-specific options in effect
> for a file system.
>
> The problem originated in this GIT commit:
>    Move platform specific mount option parse out of core XFS code
>    Date: 11/22/07
>    Author: Dave Chinner
>    SHA1 ID: a67d7c5f5d25d0b13a4dfb182697135b014fa478
>
> For XFS quotas, project and group quota management are mutually
> exclusive--only one can be in effect at a time.  There are two
> parts to managing quotas:  aggregating usage information; and
> enforcing limits.  It is possible to have a quota in effect
> (aggregating usage) but not enforced.
>
> These features are recorded on an XFS mount point using these flags:
>    XFS_PQUOTA_ACCT - Project quotas are aggregated
>    XFS_GQUOTA_ACCT - Group quotas are aggregated
>    XFS_OQUOTA_ENFD - Project/group quotas are enforced
>
> The code in error is in fs/xfs/linux-2.6/xfs_super.c:
>
>        if (mp->m_qflags & (XFS_PQUOTA_ACCT|XFS_OQUOTA_ENFD))
>                seq_puts(m, "," MNTOPT_PRJQUOTA);
>        else if (mp->m_qflags & XFS_PQUOTA_ACCT)
>                seq_puts(m, "," MNTOPT_PQUOTANOENF);
>
>        if (mp->m_qflags & (XFS_GQUOTA_ACCT|XFS_OQUOTA_ENFD))
>                seq_puts(m, "," MNTOPT_GRPQUOTA);
>        else if (mp->m_qflags & XFS_GQUOTA_ACCT)
>                seq_puts(m, "," MNTOPT_GQUOTANOENF);
>
> The problem is that XFS_OQUOTA_ENFD will be set in mp->m_qflags
> if either group or project quotas are enforced, and as a result
> both MNTOPT_PRJQUOTA and MNTOPT_GRPQUOTA will be shown as mount
> options.

Good catch, Alex.

> Signed-off-by: Alex Elder <aelder at sgi.com>

Reviewed-by: Felix Blyakher <felixb at sgi.com>