From: Jan Kara Subject: Re: [v8 2/5] ext4: adds project ID support Date: Mon, 12 Jan 2015 18:01:22 +0100 Message-ID: <20150112170122.GK4468@quack.suse.cz> References: <1418102548-5469-1-git-send-email-lixi@ddn.com> <1418102548-5469-3-git-send-email-lixi@ddn.com> <20150108082625.GA15339@quack.suse.cz> <2EE35986-B398-432E-92D4-EEF875381319@dilger.ca> <20150109094758.GA2576@quack.suse.cz> <20150109234627.GN31508@dastard> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Jan Kara , Andreas Dilger , Li Xi , Linux Filesystem Development List , ext4 development , linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Theodore Ts'o , Al Viro , Christoph Hellwig , Dmitry Monakhov To: Dave Chinner Return-path: Content-Disposition: inline In-Reply-To: <20150109234627.GN31508@dastard> Sender: linux-api-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-ext4.vger.kernel.org On Sat 10-01-15 10:46:27, Dave Chinner wrote: > On Fri, Jan 09, 2015 at 10:47:58AM +0100, Jan Kara wrote: > > On Thu 08-01-15 15:20:21, Andreas Dilger wrote: > > > On Jan 8, 2015, at 1:26 AM, Jan Kara wrote: > > > > On Tue 09-12-14 13:22:25, Li Xi wrote: > > > >> This patch adds a new internal field of ext4 inode to save project > > > >> identifier. Also a new flag EXT4_INODE_PROJINHERIT is added for > > > >> inheriting project ID from parent directory. > > > > I have noticed one thing you apparently changed in v7 of the patch set. > > > > See below. > > > > > > > >> diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h > > > >> index 29c43e7..8bd1da9 100644 > > > >> --- a/fs/ext4/ext4.h > > > >> +++ b/fs/ext4/ext4.h > > > >> @@ -377,16 +377,18 @@ struct flex_groups { > > > >> #define EXT4_EA_INODE_FL 0x00200000 /* Inode used for large EA */ > > > >> #define EXT4_EOFBLOCKS_FL 0x00400000 /* Blocks allocated beyond EOF */ > > > >> #define EXT4_INLINE_DATA_FL 0x10000000 /* Inode has inline data. */ > > > >> +#define EXT4_PROJINHERIT_FL FS_PROJINHERIT_FL /* Create with parents projid */ > > > > How did FS_PROJINHERIT_FL get here? There used to be 0x20000000 in older > > > > version of the patch set which is correct - this definition is defining > > > > ext4 on-disk format. As such it is an ext4 specific flag and should be > > > > definined to a fixed constant independed of any other filesystem. It seems > > > > you are somewhat mixing what is an on-disk format flag value and what is a > > > > flag value passed from userspace. These two may be different things and > > > > you need to convert between the values when getting / setting flags... > > > > > > Currently the EXT4_*_FL and FS_*_FL values are all identical, and there > > > is no reason to change that before it is actually needed. Since the > > > FS_PROJINHERIT_FL is used via chattr/lsattr from userspace, this value > > > must also be kept the same in the future to avoid API breakage, so there > > > is no reason to worry about incompatibilities. > > Agreed. I was somewhat worried about having on-disk flag defined through > > the external non-ext4 define but you are right that neither can really > > change once we ship a kernel with it. > > > > > See also the [v8 5/5] patch, which is changing the EXT4_*_FL values to > > > use FS_*_FL constants, where applicable, so that it is more clear that > > > these values need to be the same. > > OK, I've missed that. So if things will be consistent again, I'm fine > > with the change. > > Except that I NACK'd that change (i.e patch 4/5) because it's out of > scope of a "support project quota" patchset. not to mention that it > is broken because it exhausts the flags space with ext4 specific > flags and prevents future expansion of the ioctl structure. I agree with your objections from that review (which is why I didn't reply to that email since I didn't have more to say). > Any extension to the ioctl needs to be done in a spearate patch set, > with separate justification. This patch set should only implement > the very minimum needed to use the project quota ioctl flags.... Agreed. I was just saying that I have nothing against defining ext4 flag values using FS_*_FL where possible. Honza -- Jan Kara SUSE Labs, CR