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Date: Wed, 20 May 2020 13:55:09 -0700 From: "Darrick J. Wong" <darrick.wong@...cle.com> To: Ira Weiny <ira.weiny@...el.com> Cc: Andreas Dilger <adilger@...ger.ca>, Ext4 Developers List <linux-ext4@...r.kernel.org>, "Theodore Y. Ts'o" <tytso@....edu>, Jan Kara <jack@...e.cz>, Eric Biggers <ebiggers@...nel.org>, Al Viro <viro@...iv.linux.org.uk>, Dan Williams <dan.j.williams@...el.com>, Dave Chinner <david@...morbit.com>, Christoph Hellwig <hch@....de>, Jeff Moyer <jmoyer@...hat.com>, linux-fsdevel <linux-fsdevel@...r.kernel.org>, Linux Kernel Mailing List <linux-kernel@...r.kernel.org>, Li Xi <lixi@....com> Subject: Re: [PATCH V3 7/8] fs/ext4: Introduce DAX inode flag On Wed, May 20, 2020 at 01:02:42PM -0700, Ira Weiny wrote: > On Wed, May 20, 2020 at 01:26:44PM -0600, Andreas Dilger wrote: > > On May 19, 2020, at 11:57 PM, ira.weiny@...el.com wrote: > > > > > > From: Ira Weiny <ira.weiny@...el.com> > > > > > > Add a flag to preserve FS_XFLAG_DAX in the ext4 inode. > > > > > > Set the flag to be user visible and changeable. Set the flag to be > > > inherited. Allow applications to change the flag at any time with the > > > exception of if VERITY or ENCRYPT is set. > > > > > > Disallow setting VERITY or ENCRYPT if DAX is set. > > > > > > Finally, on regular files, flag the inode to not be cached to facilitate > > > changing S_DAX on the next creation of the inode. > > > > > > Signed-off-by: Ira Weiny <ira.weiny@...el.com> > > > > > > --- > > > diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h > > > index 6235440e4c39..467c30a789b6 100644 > > > --- a/fs/ext4/ext4.h > > > +++ b/fs/ext4/ext4.h > > > @@ -415,13 +415,16 @@ struct flex_groups { > > > #define EXT4_VERITY_FL 0x00100000 /* Verity protected inode */ > > > #define EXT4_EA_INODE_FL 0x00200000 /* Inode used for large EA */ > > > /* 0x00400000 was formerly EXT4_EOFBLOCKS_FL */ > > > + > > > +#define EXT4_DAX_FL 0x01000000 /* Inode is DAX */ > > > + > > > #define EXT4_INLINE_DATA_FL 0x10000000 /* Inode has inline data. */ > > > #define EXT4_PROJINHERIT_FL 0x20000000 /* Create with parents projid */ > > > #define EXT4_CASEFOLD_FL 0x40000000 /* Casefolded file */ > > > #define EXT4_RESERVED_FL 0x80000000 /* reserved for ext4 lib */ > > > > Hi Ira, > > This flag value conflicts with the reserved flag in e2fsprogs for snapshots: > > > > #define EXT4_SNAPFILE_FL 0x01000000 /* Inode is a snapshot */ > > Sure NP but is that new? I'm building off of 5.7-rc4. > > Just curious if I completely missed something. Yeah, you missed that ... for some reason the kernel ext4 driver is missing flags that are in e2fsprogs. (huh??) I would say you could probably just take over the flag because the 2010s called and they don't want next3 back. I guess that leaves 0x02000000 as the sole unclaimed bit, but this seriously needs some cleaning. --D > > > > Please change EXT4_DAX_FL and FS_DAX_FL to use 0x02000000, which is not used > > for anything in either case. > > NP, thanks! > Ira > > > > > Cheers, Andreas > > > > > > > diff --git a/include/uapi/linux/fs.h b/include/uapi/linux/fs.h > > > index 379a612f8f1d..7c5f6eb51e2d 100644 > > > --- a/include/uapi/linux/fs.h > > > +++ b/include/uapi/linux/fs.h > > > @@ -262,6 +262,7 @@ struct fsxattr { > > > #define FS_EA_INODE_FL 0x00200000 /* Inode used for large EA */ > > > #define FS_EOFBLOCKS_FL 0x00400000 /* Reserved for ext4 */ > > > #define FS_NOCOW_FL 0x00800000 /* Do not cow file */ > > > +#define FS_DAX_FL 0x01000000 /* Inode is DAX */ > > > #define FS_INLINE_DATA_FL 0x10000000 /* Reserved for ext4 */ > > > #define FS_PROJINHERIT_FL 0x20000000 /* Create with parents projid */ > > > #define FS_CASEFOLD_FL 0x40000000 /* Folder is case insensitive */ > > > -- > > > 2.25.1 > > > > > > > > > Cheers, Andreas > > > > > > > > > > > >
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