From: Christoph Hellwig <hch@lst.de>
Date: Mon, 29 Aug 2016 01:33:58 +0000 (+1000)
Subject: iomap: don't set FIEMAP_EXTENT_MERGED for extent based filesystems
X-Git-Tag: v4.9.8~1145^2~85
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=17de0a9ff3df8f54f2f47746d118112d4e61d973;p=platform%2Fkernel%2Flinux-rpi3.git

iomap: don't set FIEMAP_EXTENT_MERGED for extent based filesystems

Filesystems like XFS that use extents should not set the
FIEMAP_EXTENT_MERGED flag in the fiemap extent structures.  To allow
for both behaviors for the upcoming gfs2 usage split the iomap
type field into type and flags, and only set FIEMAP_EXTENT_MERGED if
the IOMAP_F_MERGED flag is set.  The flags field will also come in
handy for future features such as shared extents on reflink-enabled
file systems.

Reported-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
---

diff --git a/fs/iomap.c b/fs/iomap.c
index 0342254..706270f 100644
--- a/fs/iomap.c
+++ b/fs/iomap.c
@@ -428,9 +428,12 @@ static int iomap_to_fiemap(struct fiemap_extent_info *fi,
 		break;
 	}
 
+	if (iomap->flags & IOMAP_F_MERGED)
+		flags |= FIEMAP_EXTENT_MERGED;
+
 	return fiemap_fill_next_extent(fi, iomap->offset,
 			iomap->blkno != IOMAP_NULL_BLOCK ? iomap->blkno << 9: 0,
-			iomap->length, flags | FIEMAP_EXTENT_MERGED);
+			iomap->length, flags);
 
 }
 
diff --git a/include/linux/iomap.h b/include/linux/iomap.h
index 3267df4..3d70ece 100644
--- a/include/linux/iomap.h
+++ b/include/linux/iomap.h
@@ -19,6 +19,11 @@ struct vm_fault;
 #define IOMAP_UNWRITTEN	0x04	/* blocks allocated @blkno in unwritten state */
 
 /*
+ * Flags for iomap mappings:
+ */
+#define IOMAP_F_MERGED	0x01	/* contains multiple blocks/extents */
+
+/*
  * Magic value for blkno:
  */
 #define IOMAP_NULL_BLOCK -1LL	/* blkno is not valid */
@@ -27,7 +32,8 @@ struct iomap {
 	sector_t		blkno;	/* 1st sector of mapping, 512b units */
 	loff_t			offset;	/* file offset of mapping, bytes */
 	u64			length;	/* length of mapping, bytes */
-	int			type;	/* type of mapping */
+	u16			type;	/* type of mapping */
+	u16			flags;	/* flags for mapping */
 	struct block_device	*bdev;	/* block device for I/O */
 };