fs: port ->setattr() to pass mnt_idmap

Convert to struct mnt_idmap.

Last cycle we merged the necessary infrastructure in
256c8aed2b42 ("fs: introduce dedicated idmap type for mounts").
This is just the conversion to struct mnt_idmap.

Currently we still pass around the plain namespace that was attached to a
mount. This is in general pretty convenient but it makes it easy to
conflate namespaces that are relevant on the filesystem with namespaces
that are relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.

Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.

Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>

3 files changed, 8 insertions, 7 deletions

diff --git a/fs/ocfs2/dlmfs/dlmfs.c b/fs/ocfs2/dlmfs/dlmfs.c
index 8b2020f92b5f..2d907ac86409 100644
--- a/fs/ocfs2/dlmfs/dlmfs.c
+++ b/fs/ocfs2/dlmfs/dlmfs.c
@@ -188,18 +188,18 @@ static int dlmfs_file_release(struct inode *inode,
  * We do ->setattr() just to override size changes.  Our size is the size
  * of the LVB and nothing else.
  */
-static int dlmfs_file_setattr(struct user_namespace *mnt_userns,
+static int dlmfs_file_setattr(struct mnt_idmap *idmap,
 			      struct dentry *dentry, struct iattr *attr)
 {
 	int error;
 	struct inode *inode = d_inode(dentry);
 
 	attr->ia_valid &= ~ATTR_SIZE;
-	error = setattr_prepare(&init_user_ns, dentry, attr);
+	error = setattr_prepare(&nop_mnt_idmap, dentry, attr);
 	if (error)
 		return error;
 
-	setattr_copy(&init_user_ns, inode, attr);
+	setattr_copy(&nop_mnt_idmap, inode, attr);
 	mark_inode_dirty(inode);
 	return 0;
 }
diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c
index 5c60b6bc85bf..e157deb68d38 100644
--- a/fs/ocfs2/file.c
+++ b/fs/ocfs2/file.c
@@ -1111,9 +1111,10 @@ out:
 	return ret;
 }
 
-int ocfs2_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
+int ocfs2_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 		  struct iattr *attr)
 {
+	struct user_namespace *mnt_userns = mnt_idmap_owner(idmap);
 	int status = 0, size_change;
 	int inode_locked = 0;
 	struct inode *inode = d_inode(dentry);
@@ -1142,7 +1143,7 @@ int ocfs2_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
 	if (!(attr->ia_valid & OCFS2_VALID_ATTRS))
 		return 0;
 
-	status = setattr_prepare(&init_user_ns, dentry, attr);
+	status = setattr_prepare(&nop_mnt_idmap, dentry, attr);
 	if (status)
 		return status;
 
@@ -1265,7 +1266,7 @@ int ocfs2_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
 		}
 	}
 
-	setattr_copy(&init_user_ns, inode, attr);
+	setattr_copy(&nop_mnt_idmap, inode, attr);
 	mark_inode_dirty(inode);
 
 	status = ocfs2_mark_inode_dirty(handle, inode, bh);
diff --git a/fs/ocfs2/file.h b/fs/ocfs2/file.h
index 71db8f3aa027..76020b348df2 100644
--- a/fs/ocfs2/file.h
+++ b/fs/ocfs2/file.h
@@ -49,7 +49,7 @@ int ocfs2_extend_no_holes(struct inode *inode, struct buffer_head *di_bh,
 			  u64 new_i_size, u64 zero_to);
 int ocfs2_zero_extend(struct inode *inode, struct buffer_head *di_bh,
 		      loff_t zero_to);
-int ocfs2_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
+int ocfs2_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 		  struct iattr *attr);
 int ocfs2_getattr(struct user_namespace *mnt_userns, const struct path *path,
 		  struct kstat *stat, u32 request_mask, unsigned int flags);