Re: [PATCH] design: Document project quota inode

[Carlos Maiolino <cmaiolino@redhat.com>]

On Tue, Aug 07, 2018 at 08:28:06AM -0700, Darrick J. Wong wrote:
> On Tue, Aug 07, 2018 at 08:10:50AM -0700, Darrick J. Wong wrote:
> > On Mon, Aug 06, 2018 at 06:10:32PM -0300, Marco Benatto wrote:
> > > A project quota inode was introduced into V5 superblock allowing
> > > project quotas and group quotas to be used simultaneously. However
> > > on "Quota Inodes" section we still mention it's not possible to
> > > use project and group quotas at sametime.
> > > 
> > > This patch documents this behavior for V5 and later superblocks,
> > > while keeps documented the old behavior for earlier versions.
> > > 
> > > Signed-off-by: Marco Benatto <mbenatto@redhat.com>
> > 
> > Looks ok,
> > Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
> > 
> > --D
> > 
> > > ---
> > >  design/XFS_Filesystem_Structure/internal_inodes.asciidoc | 11 +++++++----
> > >  1 file changed, 7 insertions(+), 4 deletions(-)
> > > 
> > > diff --git a/design/XFS_Filesystem_Structure/internal_inodes.asciidoc b/design/XFS_Filesystem_Structure/internal_inodes.asciidoc
> > > index f5c2654..b694e74 100644
> > > --- a/design/XFS_Filesystem_Structure/internal_inodes.asciidoc
> > > +++ b/design/XFS_Filesystem_Structure/internal_inodes.asciidoc
> > > @@ -8,9 +8,12 @@ accessible from the superblock.
> > >  [[Quota_Inodes]]
> > >  == Quota Inodes
> > >  
> > > -If quotas are used, two inodes are allocated for user and group quota
> > > -management. If project quotas are used, these replace the group quota management
> > > -and therefore uses the group quota inode.
> > > +If quotas are used, prior to version 5 superblocks, two inodes are allocated for
> > > +user and group management. In this case if project quotas are used, these replace
> > > +the group quota management and therefore uses the group quota inode.
> > > +
> > > +In version 5 superblock or later a third inode will be allocated to project quota
> > > +management, making it possible to use group and project quotas management simultaneously.
> 
> Ugh, /me has post-review regrets... mind if I rearrange this a little?
> 
> "Prior to version 5 filesystems, two inodes can be allocated for quota
> management.  The first inode will be used for user quotas.  The second
> inode will be used for group quotas or project quotas, depending on
> mount options.  Group and project quotas are mutually exclusive features
> in these environments.
> 
> "In version 5 or later filesystems, each quota type is allocated its own
> inode, making it possible to use group and project quota management
> simultaneously."
> 

FWIW

Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>



> --D
> 
> > >  
> > >  * Project quota's primary purpose is to track and monitor disk usage for
> > >  directories. For this to occur, the directory inode must have the
> > > @@ -28,7 +31,7 @@ multiplied by the size of +xfs_dqblk_t+ (136 bytes).
> > >  .Quota inode layout
> > >  image::images/76.png[]
> > >  
> > > -Quota information is stored in the data extents of the two reserved quota
> > > +Quota information is stored in the data extents of the reserved quota
> > >  inodes as an array of the +xfs_dqblk+ structures, where there is one array
> > >  element for each ID in the system:
> > >  
> > > -- 
> > > 2.9.5
> > > 
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-- 
Carlos