[PATCH 4/5] fibmap: Use bmap instead of ->bmap method in ioctl_fibmap

[Carlos Maiolino <cmaiolino@xxxxxxxxxx>]

Now we have the possibility of proper error return in bmap, use bmap()
function in ioctl_fibmap() instead of calling ->bmap method directly.

Reviewed-by: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Carlos Maiolino <cmaiolino@xxxxxxxxxx>
---
 fs/ioctl.c         | 29 +++++++++++++++++++----------
 include/linux/fs.h |  9 ++++++++-
 2 files changed, 27 insertions(+), 11 deletions(-)

diff --git a/fs/ioctl.c b/fs/ioctl.c
index 2f5e4e5b97e1..83f36feaf781 100644
--- a/fs/ioctl.c
+++ b/fs/ioctl.c
@@ -54,19 +54,28 @@ EXPORT_SYMBOL(vfs_ioctl);
 
 static int ioctl_fibmap(struct file *filp, int __user *p)
 {
-	struct address_space *mapping = filp->f_mapping;
-	int res, block;
+	struct inode *inode = file_inode(filp);
+	int error, ur_block;
+	sector_t block;
 
-	/* do we support this mess? */
-	if (!mapping->a_ops->bmap)
-		return -EINVAL;
 	if (!capable(CAP_SYS_RAWIO))
 		return -EPERM;
-	res = get_user(block, p);
-	if (res)
-		return res;
-	res = mapping->a_ops->bmap(mapping, block);
-	return put_user(res, p);
+
+	error = get_user(ur_block, p);
+	if (error)
+		return error;
+
+	block = ur_block;
+	error = bmap(inode, &block);
+
+	if (error)
+		ur_block = 0;
+	else
+		ur_block = block;
+
+	error = put_user(ur_block, p);
+
+	return error;
 }
 
 /**
diff --git a/include/linux/fs.h b/include/linux/fs.h
index c5b86e53e568..7d9bda8ef3db 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2865,9 +2865,16 @@ static inline ssize_t generic_write_sync(struct kiocb *iocb, ssize_t count)
 
 extern void emergency_sync(void);
 extern void emergency_remount(void);
+
 #ifdef CONFIG_BLOCK
-extern int bmap(struct inode *, sector_t *);
+extern int bmap(struct inode *inode, sector_t *block);
+#else
+static inline int bmap(struct inode *inode,  sector_t *block)
+{
+	return -EINVAL;
+}
 #endif
+
 extern int notify_change(struct dentry *, struct iattr *, struct inode **);
 extern int inode_permission(struct inode *, int);
 extern int generic_permission(struct inode *, int);
-- 
2.23.0