[Cluster-devel] [PATCH v2 3/3] GFS2: Switch fiemap implementation to use iomap

[Bob Peterson <rpeterso@redhat.com>]

This patch switches GFS2's implementation of fiemap from the old
block_map code to the new iomap interface.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
---
 fs/gfs2/Kconfig       |  1 +
 fs/gfs2/inode.c       | 60 ++++++++++++++++++++++++++++++++++++++++-----------
 include/linux/iomap.h |  1 +
 3 files changed, 50 insertions(+), 12 deletions(-)

diff --git a/fs/gfs2/Kconfig b/fs/gfs2/Kconfig
index 90c6a8f..43c827a 100644
--- a/fs/gfs2/Kconfig
+++ b/fs/gfs2/Kconfig
@@ -4,6 +4,7 @@ config GFS2_FS
 	select FS_POSIX_ACL
 	select CRC32
 	select QUOTACTL
+	select FS_IOMAP
 	help
 	  A cluster filesystem.
 
diff --git a/fs/gfs2/inode.c b/fs/gfs2/inode.c
index fe3f849..322d178 100644
--- a/fs/gfs2/inode.c
+++ b/fs/gfs2/inode.c
@@ -17,7 +17,7 @@
 #include <linux/posix_acl.h>
 #include <linux/gfs2_ondisk.h>
 #include <linux/crc32.h>
-#include <linux/fiemap.h>
+#include <linux/iomap.h>
 #include <linux/security.h>
 #include <asm/uaccess.h>
 
@@ -1994,28 +1994,64 @@ static int gfs2_getattr(struct vfsmount *mnt, struct dentry *dentry,
 	return 0;
 }
 
+static int gfs2_iomap_fiemap_begin(struct inode *inode, loff_t offset,
+				   loff_t length, unsigned flags,
+				   struct iomap *iomap)
+{
+	struct gfs2_inode *ip = GFS2_I(inode);
+	struct gfs2_holder *gh;
+	int ret;
+
+	gh = kzalloc(sizeof(struct gfs2_holder), GFP_NOFS);
+	if (!gh)
+		return -ENOMEM;
+
+	ret = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, 0, gh);
+	if (ret) {
+		kfree(gh);
+		return ret;
+	}
+	iomap->private = gh;
+	ret = gfs2_get_iomap(inode, offset, length, iomap);
+	if (ret)
+		gfs2_glock_dq_uninit(gh);
+	return ret;
+}
+
+static int gfs2_iomap_fiemap_end(struct inode *inode, loff_t offset,
+				 loff_t length, ssize_t written,
+				 unsigned flags, struct iomap *iomap)
+{
+	struct gfs2_holder *gh = iomap->private;
+
+	BUG_ON(gh == NULL);
+	gfs2_glock_dq_uninit(gh);
+	return 0;
+}
+
 static int gfs2_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
 		       u64 start, u64 len)
 {
 	struct gfs2_inode *ip = GFS2_I(inode);
-	struct gfs2_holder gh;
 	int ret;
 
-	ret = fiemap_check_flags(fieinfo, FIEMAP_FLAG_SYNC);
-	if (ret)
-		return ret;
+	struct iomap_ops gfs2_iomap_fiemap_ops = {
+		.iomap_begin = gfs2_iomap_fiemap_begin,
+		.iomap_end = gfs2_iomap_fiemap_end,
+	};
 
 	inode_lock(inode);
 
-	ret = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, 0, &gh);
-	if (ret)
-		goto out;
-
 	if (gfs2_is_stuffed(ip)) {
+		struct gfs2_holder gh;
 		u64 phys = ip->i_no_addr << inode->i_blkbits;
 		u64 size = i_size_read(inode);
 		u32 flags = FIEMAP_EXTENT_LAST|FIEMAP_EXTENT_NOT_ALIGNED|
 			    FIEMAP_EXTENT_DATA_INLINE;
+		ret = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, 0, &gh);
+		if (ret)
+			goto out;
+
 		phys += sizeof(struct gfs2_dinode);
 		phys += start;
 		if (start + len > size)
@@ -2025,12 +2061,12 @@ static int gfs2_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
 						      len, flags);
 		if (ret == 1)
 			ret = 0;
+		gfs2_glock_dq_uninit(&gh);
 	} else {
-		ret = __generic_block_fiemap(inode, fieinfo, start, len,
-					     gfs2_block_map);
+		ret = iomap_fiemap(inode, fieinfo, start, len,
+				   &gfs2_iomap_fiemap_ops);
 	}
 
-	gfs2_glock_dq_uninit(&gh);
 out:
 	inode_unlock(inode);
 	return ret;
diff --git a/include/linux/iomap.h b/include/linux/iomap.h
index e63e288..0f177d3 100644
--- a/include/linux/iomap.h
+++ b/include/linux/iomap.h
@@ -37,6 +37,7 @@ struct iomap {
 	u16			type;	/* type of mapping */
 	u16			flags;	/* flags for mapping */
 	struct block_device	*bdev;	/* block device for I/O */
+	void			*private; /* private value for fs use */
 };
 
 /*
-- 
2.7.4