On Fri, Sep 08, 2017 at 01:02:15PM -0500, Eric Sandeen wrote:

On 9/4/17 12:45 PM, Darrick J. Wong wrote:

quoted

Create a -d option to mkfs.xfs that enables administrators to set
the CoW extent size hint on the created files.

Signed-off-by: Darrick J. Wong <redacted>
---
v2: port flags2diflags from the kernel

hm, I wonder if we need a libxfs/util.c in the kernel for stuff like
this so libxfs diff will keep such things in sync in the future.

a project for another day I guess.  One question below.

quoted

---
 libxfs/util.c       |   64 +++++++++++++++++++++++++++++++++++++++++++++++++--
 man/man8/mkfs.xfs.8 |    7 ++++++
 mkfs/xfs_mkfs.c     |   20 ++++++++++++++++
 3 files changed, 89 insertions(+), 2 deletions(-)

diff --git a/libxfs/util.c b/libxfs/util.c
index 0e2f29e..b600594 100644
--- a/libxfs/util.c
+++ b/libxfs/util.c

@@ -175,6 +175,64 @@ libxfs_trans_ichgtime(
 	}
 }
 
+STATIC uint16_t
+xfs_flags2diflags(
+	struct xfs_inode	*ip,
+	unsigned int		xflags)
+{
+	/* can't set PREALLOC this way, just preserve it */
+	uint16_t		di_flags =
+		(ip->i_d.di_flags & XFS_DIFLAG_PREALLOC);
+
+	if (xflags & FS_XFLAG_IMMUTABLE)
+		di_flags |= XFS_DIFLAG_IMMUTABLE;
+	if (xflags & FS_XFLAG_APPEND)
+		di_flags |= XFS_DIFLAG_APPEND;
+	if (xflags & FS_XFLAG_SYNC)
+		di_flags |= XFS_DIFLAG_SYNC;
+	if (xflags & FS_XFLAG_NOATIME)
+		di_flags |= XFS_DIFLAG_NOATIME;
+	if (xflags & FS_XFLAG_NODUMP)
+		di_flags |= XFS_DIFLAG_NODUMP;
+	if (xflags & FS_XFLAG_NODEFRAG)
+		di_flags |= XFS_DIFLAG_NODEFRAG;
+	if (xflags & FS_XFLAG_FILESTREAM)
+		di_flags |= XFS_DIFLAG_FILESTREAM;
+	if (S_ISDIR(VFS_I(ip)->i_mode)) {
+		if (xflags & FS_XFLAG_RTINHERIT)
+			di_flags |= XFS_DIFLAG_RTINHERIT;
+		if (xflags & FS_XFLAG_NOSYMLINKS)
+			di_flags |= XFS_DIFLAG_NOSYMLINKS;
+		if (xflags & FS_XFLAG_EXTSZINHERIT)
+			di_flags |= XFS_DIFLAG_EXTSZINHERIT;
+		if (xflags & FS_XFLAG_PROJINHERIT)
+			di_flags |= XFS_DIFLAG_PROJINHERIT;
+	} else if (S_ISREG(VFS_I(ip)->i_mode)) {
+		if (xflags & FS_XFLAG_REALTIME)
+			di_flags |= XFS_DIFLAG_REALTIME;
+		if (xflags & FS_XFLAG_EXTSIZE)
+			di_flags |= XFS_DIFLAG_EXTSIZE;
+	}
+
+	return di_flags;
+}
+
+STATIC uint64_t
+xfs_flags2diflags2(
+	struct xfs_inode	*ip,
+	unsigned int		xflags)
+{
+	uint64_t		di_flags2 =
+		(ip->i_d.di_flags2 & XFS_DIFLAG2_REFLINK);
+
+	if (xflags & FS_XFLAG_DAX)
+		di_flags2 |= XFS_DIFLAG2_DAX;
+	if (xflags & FS_XFLAG_COWEXTSIZE)
+		di_flags2 |= XFS_DIFLAG2_COWEXTSIZE;
+
+	return di_flags2;
+}
+
 /*
  * Allocate an inode on disk and return a copy of its in-core version.
  * Set mode, nlink, and rdev appropriately within the inode.

@@ -254,15 +312,17 @@ libxfs_ialloc(
 	ip->i_d.di_extsize = pip ? 0 : fsx->fsx_extsize;
 	ip->i_d.di_dmevmask = 0;
 	ip->i_d.di_dmstate = 0;
-	ip->i_d.di_flags = pip ? 0 : fsx->fsx_xflags;
+	ip->i_d.di_flags = pip ? 0 : xfs_flags2diflags(ip, fsx->fsx_xflags);

is this a bugfix?

No.

Prior to this patch, the only fsx_xflags bits that mkfs could set are
the ones that correspond exactly to di_flags bits, so it was fine to set
them directly.  Subtle and annoying, but it worked.

However, the xfs_mkfs.c changes enable us to set FS_XFLAG_COWEXTSIZE,
which doesn't correspond to a di_flags bit, so now we need translation
functions to return the correct di_flags/di_flags2 values for the given
fsx_xflags.

(Granted you could argue that COWEXTSIZE is bit 17 so it'll just get
truncated when we set di_flags and therefore it's not absolutely
necessary to have a translation function for di_flags but that's
sloppy.)

--D

The rest seems ok, just wondering if the above should be hidden in here -
at least a mention of the change in the changelog seems needed, but most
likely thjis is a separate change, no?  Or am I missing something?

-Eric
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