On Mon, Apr 29, 2024 at 05:47:33PM +0000, John Garry wrote: > From: "Darrick J. Wong" <djwong@xxxxxxxxxx> > > Add a new inode flag to require that all file data extent mappings must > be aligned (both the file offset range and the allocated space itself) > to the extent size hint. Having a separate COW extent size hint is no > longer allowed. > > The goal here is to enable sysadmins and users to mandate that all space > mappings in a file must have a startoff/blockcount that are aligned to > (say) a 2MB alignment and that the startblock/blockcount will follow the > same alignment. > > jpg: Enforce extsize is a power-of-2 and aligned with afgsize + stripe > alignment for forcealign > Signed-off-by: "Darrick J. Wong" <djwong@xxxxxxxxxx> > Co-developed-by: John Garry <john.g.garry@xxxxxxxxxx> > Signed-off-by: John Garry <john.g.garry@xxxxxxxxxx> > --- > fs/xfs/libxfs/xfs_format.h | 6 ++++- > fs/xfs/libxfs/xfs_inode_buf.c | 50 +++++++++++++++++++++++++++++++++++ > fs/xfs/libxfs/xfs_inode_buf.h | 3 +++ > fs/xfs/libxfs/xfs_sb.c | 2 ++ > fs/xfs/xfs_inode.c | 12 +++++++++ > fs/xfs/xfs_inode.h | 2 +- > fs/xfs/xfs_ioctl.c | 34 +++++++++++++++++++++++- > fs/xfs/xfs_mount.h | 2 ++ > fs/xfs/xfs_super.c | 4 +++ > include/uapi/linux/fs.h | 2 ++ > 10 files changed, 114 insertions(+), 3 deletions(-) > > diff --git a/fs/xfs/libxfs/xfs_format.h b/fs/xfs/libxfs/xfs_format.h > index 2b2f9050fbfb..4dd295b047f8 100644 > --- a/fs/xfs/libxfs/xfs_format.h > +++ b/fs/xfs/libxfs/xfs_format.h > @@ -353,6 +353,7 @@ xfs_sb_has_compat_feature( > #define XFS_SB_FEAT_RO_COMPAT_RMAPBT (1 << 1) /* reverse map btree */ > #define XFS_SB_FEAT_RO_COMPAT_REFLINK (1 << 2) /* reflinked files */ > #define XFS_SB_FEAT_RO_COMPAT_INOBTCNT (1 << 3) /* inobt block counts */ > +#define XFS_SB_FEAT_RO_COMPAT_FORCEALIGN (1 << 30) /* aligned file data extents */ Hi, John You know I've been using and testing your atomic writes patch series recently, and I'm particularly interested in the changes to the on-disk format. I noticed that XFS_SB_FEAT_RO_COMPAT_FORCEALIGN uses bit 30 instead of bit 4, which would be the next available bit in sequence. I'm wondering if using bit 30 is just a temporary solution to avoid conflicts, and if the plan is to eventually use bits sequentially, for example, using bit 4? I'm looking forward to your explanation. Thanks, Long Li
