quota: port to mnt_idmap

Convert to struct mnt_idmap.

Last cycle we merged the necessary infrastructure in
256c8aed2b ("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>

fs/ext2/inode.c

@@ -1621,7 +1621,6 @@ int ext2_getattr(struct mnt_idmap *idmap, const struct path *path,
 int ext2_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 		 struct iattr *iattr)
 {
-	struct user_namespace *mnt_userns = mnt_idmap_owner(idmap);
 	struct inode *inode = d_inode(dentry);
 	int error;
 
@@ -1629,14 +1628,14 @@ int ext2_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 	if (error)
 		return error;
 
-	if (is_quota_modification(mnt_userns, inode, iattr)) {
+	if (is_quota_modification(&nop_mnt_idmap, inode, iattr)) {
 		error = dquot_initialize(inode);
 		if (error)
 			return error;
 	}
-	if (i_uid_needs_update(mnt_userns, iattr, inode) ||
-	    i_gid_needs_update(mnt_userns, iattr, inode)) {
-		error = dquot_transfer(mnt_userns, inode, iattr);
+	if (i_uid_needs_update(&nop_mnt_idmap, iattr, inode) ||
+	    i_gid_needs_update(&nop_mnt_idmap, iattr, inode)) {
+		error = dquot_transfer(&nop_mnt_idmap, inode, iattr);
 		if (error)
 			return error;
 	}

fs/ext4/inode.c

@@ -5467,7 +5467,7 @@ int ext4_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 	if (error)
 		return error;
 
-	if (is_quota_modification(mnt_userns, inode, attr)) {
+	if (is_quota_modification(idmap, inode, attr)) {
 		error = dquot_initialize(inode);
 		if (error)
 			return error;
@@ -5491,7 +5491,7 @@ int ext4_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 		 * counts xattr inode references.
 		 */
 		down_read(&EXT4_I(inode)->xattr_sem);
-		error = dquot_transfer(mnt_userns, inode, attr);
+		error = dquot_transfer(idmap, inode, attr);
 		up_read(&EXT4_I(inode)->xattr_sem);
 
 		if (error) {

fs/f2fs/file.c

@@ -965,7 +965,7 @@ int f2fs_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 	if (err)
 		return err;
 
-	if (is_quota_modification(mnt_userns, inode, attr)) {
+	if (is_quota_modification(idmap, inode, attr)) {
 		err = f2fs_dquot_initialize(inode);
 		if (err)
 			return err;
@@ -973,7 +973,7 @@ int f2fs_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 	if (i_uid_needs_update(mnt_userns, attr, inode) ||
 	    i_gid_needs_update(mnt_userns, attr, inode)) {
 		f2fs_lock_op(F2FS_I_SB(inode));
-		err = dquot_transfer(mnt_userns, inode, attr);
+		err = dquot_transfer(idmap, inode, attr);
 		if (err) {
 			set_sbi_flag(F2FS_I_SB(inode),
 					SBI_QUOTA_NEED_REPAIR);

fs/f2fs/recovery.c

@@ -266,7 +266,7 @@ static int recover_quota_data(struct inode *inode, struct page *page)
 	if (!attr.ia_valid)
 		return 0;
 
-	err = dquot_transfer(&init_user_ns, inode, &attr);
+	err = dquot_transfer(&nop_mnt_idmap, inode, &attr);
 	if (err)
 		set_sbi_flag(F2FS_I_SB(inode), SBI_QUOTA_NEED_REPAIR);
 	return err;

fs/jfs/file.c

@@ -95,14 +95,14 @@ int jfs_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 	if (rc)
 		return rc;
 
-	if (is_quota_modification(&init_user_ns, inode, iattr)) {
+	if (is_quota_modification(&nop_mnt_idmap, inode, iattr)) {
 		rc = dquot_initialize(inode);
 		if (rc)
 			return rc;
 	}
 	if ((iattr->ia_valid & ATTR_UID && !uid_eq(iattr->ia_uid, inode->i_uid)) ||
 	    (iattr->ia_valid & ATTR_GID && !gid_eq(iattr->ia_gid, inode->i_gid))) {
-		rc = dquot_transfer(&init_user_ns, inode, iattr);
+		rc = dquot_transfer(&nop_mnt_idmap, inode, iattr);
 		if (rc)
 			return rc;
 	}

fs/ocfs2/file.c

@@ -1114,7 +1114,6 @@ out:
 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);
@@ -1147,7 +1146,7 @@ int ocfs2_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 	if (status)
 		return status;
 
-	if (is_quota_modification(mnt_userns, inode, attr)) {
+	if (is_quota_modification(&nop_mnt_idmap, inode, attr)) {
 		status = dquot_initialize(inode);
 		if (status)
 			return status;

fs/quota/dquot.c

@@ -2085,9 +2085,10 @@ EXPORT_SYMBOL(__dquot_transfer);
 /* Wrapper for transferring ownership of an inode for uid/gid only
  * Called from FSXXX_setattr()
  */
-int dquot_transfer(struct user_namespace *mnt_userns, struct inode *inode,
+int dquot_transfer(struct mnt_idmap *idmap, struct inode *inode,
 		   struct iattr *iattr)
 {
+	struct user_namespace *mnt_userns = mnt_idmap_owner(idmap);
 	struct dquot *transfer_to[MAXQUOTAS] = {};
 	struct dquot *dquot;
 	struct super_block *sb = inode->i_sb;

fs/reiserfs/inode.c

@@ -3276,7 +3276,7 @@ int reiserfs_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 	/* must be turned off for recursive notify_change calls */
 	ia_valid = attr->ia_valid &= ~(ATTR_KILL_SUID|ATTR_KILL_SGID);
 
-	if (is_quota_modification(&init_user_ns, inode, attr)) {
+	if (is_quota_modification(&nop_mnt_idmap, inode, attr)) {
 		error = dquot_initialize(inode);
 		if (error)
 			return error;
@@ -3359,7 +3359,7 @@ int reiserfs_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 		reiserfs_write_unlock(inode->i_sb);
 		if (error)
 			goto out;
-		error = dquot_transfer(&init_user_ns, inode, attr);
+		error = dquot_transfer(&nop_mnt_idmap, inode, attr);
 		reiserfs_write_lock(inode->i_sb);
 		if (error) {
 			journal_end(&th);

fs/zonefs/super.c

@@ -626,7 +626,7 @@ static int zonefs_inode_setattr(struct mnt_idmap *idmap,
 	     !uid_eq(iattr->ia_uid, inode->i_uid)) ||
 	    ((iattr->ia_valid & ATTR_GID) &&
 	     !gid_eq(iattr->ia_gid, inode->i_gid))) {
-		ret = dquot_transfer(&init_user_ns, inode, iattr);
+		ret = dquot_transfer(&nop_mnt_idmap, inode, iattr);
 		if (ret)
 			return ret;
 	}

include/linux/quotaops.h

@@ -20,9 +20,10 @@ static inline struct quota_info *sb_dqopt(struct super_block *sb)
 }
 
 /* i_mutex must being held */
-static inline bool is_quota_modification(struct user_namespace *mnt_userns,
+static inline bool is_quota_modification(struct mnt_idmap *idmap,
 					 struct inode *inode, struct iattr *ia)
 {
+	struct user_namespace *mnt_userns = mnt_idmap_owner(idmap);
 	return ((ia->ia_valid & ATTR_SIZE) ||
 		i_uid_needs_update(mnt_userns, ia, inode) ||
 		i_gid_needs_update(mnt_userns, ia, inode));
@@ -116,7 +117,7 @@ int dquot_set_dqblk(struct super_block *sb, struct kqid id,
 		struct qc_dqblk *di);
 
 int __dquot_transfer(struct inode *inode, struct dquot **transfer_to);
-int dquot_transfer(struct user_namespace *mnt_userns, struct inode *inode,
+int dquot_transfer(struct mnt_idmap *idmap, struct inode *inode,
 		   struct iattr *iattr);
 
 static inline struct mem_dqinfo *sb_dqinfo(struct super_block *sb, int type)
@@ -236,7 +237,7 @@ static inline void dquot_free_inode(struct inode *inode)
 {
 }
 
-static inline int dquot_transfer(struct user_namespace *mnt_userns,
+static inline int dquot_transfer(struct mnt_idmap *idmap,
 				 struct inode *inode, struct iattr *iattr)
 {
 	return 0;