1 files changed, 118 insertions, 123 deletions

diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c
index 83b955a1d55c..d21f81a524f6 100644
--- a/fs/overlayfs/dir.c
+++ b/fs/overlayfs/dir.c
@@ -47,79 +47,70 @@ static int ovl_cleanup_locked(struct ovl_fs *ofs, struct inode *wdir,
 int ovl_cleanup(struct ovl_fs *ofs, struct dentry *workdir,
 		struct dentry *wdentry)
 {
-	int err;
-
-	err = ovl_parent_lock(workdir, wdentry);
-	if (err)
-		return err;
+	wdentry = start_removing_dentry(workdir, wdentry);
+	if (IS_ERR(wdentry))
+		return PTR_ERR(wdentry);
 
 	ovl_cleanup_locked(ofs, workdir->d_inode, wdentry);
-	ovl_parent_unlock(workdir);
+	end_removing(wdentry);
 
 	return 0;
 }
 
-struct dentry *ovl_lookup_temp(struct ovl_fs *ofs, struct dentry *workdir)
+void ovl_tempname(char name[OVL_TEMPNAME_SIZE])
 {
-	struct dentry *temp;
-	char name[20];
 	static atomic_t temp_id = ATOMIC_INIT(0);
 
 	/* counter is allowed to wrap, since temp dentries are ephemeral */
-	snprintf(name, sizeof(name), "#%x", atomic_inc_return(&temp_id));
+	snprintf(name, OVL_TEMPNAME_SIZE, "#%x", atomic_inc_return(&temp_id));
+}
 
-	temp = ovl_lookup_upper(ofs, name, workdir, strlen(name));
-	if (!IS_ERR(temp) && temp->d_inode) {
-		pr_err("workdir/%s already exists\n", name);
-		dput(temp);
-		temp = ERR_PTR(-EIO);
-	}
+static struct dentry *ovl_start_creating_temp(struct ovl_fs *ofs,
+					      struct dentry *workdir)
+{
+	char name[OVL_TEMPNAME_SIZE];
 
-	return temp;
+	ovl_tempname(name);
+	return start_creating(ovl_upper_mnt_idmap(ofs), workdir,
+			      &QSTR(name));
 }
 
 static struct dentry *ovl_whiteout(struct ovl_fs *ofs)
 {
 	int err;
-	struct dentry *whiteout;
+	struct dentry *whiteout, *link;
 	struct dentry *workdir = ofs->workdir;
 	struct inode *wdir = workdir->d_inode;
 
 	guard(mutex)(&ofs->whiteout_lock);
 
 	if (!ofs->whiteout) {
-		inode_lock_nested(wdir, I_MUTEX_PARENT);
-		whiteout = ovl_lookup_temp(ofs, workdir);
-		if (!IS_ERR(whiteout)) {
-			err = ovl_do_whiteout(ofs, wdir, whiteout);
-			if (err) {
-				dput(whiteout);
-				whiteout = ERR_PTR(err);
-			}
-		}
-		inode_unlock(wdir);
+		whiteout = ovl_start_creating_temp(ofs, workdir);
 		if (IS_ERR(whiteout))
 			return whiteout;
-		ofs->whiteout = whiteout;
+		err = ovl_do_whiteout(ofs, wdir, whiteout);
+		if (!err)
+			ofs->whiteout = dget(whiteout);
+		end_creating(whiteout);
+		if (err)
+			return ERR_PTR(err);
 	}
 
 	if (!ofs->no_shared_whiteout) {
-		inode_lock_nested(wdir, I_MUTEX_PARENT);
-		whiteout = ovl_lookup_temp(ofs, workdir);
-		if (!IS_ERR(whiteout)) {
-			err = ovl_do_link(ofs, ofs->whiteout, wdir, whiteout);
-			if (err) {
-				dput(whiteout);
-				whiteout = ERR_PTR(err);
-			}
-		}
-		inode_unlock(wdir);
-		if (!IS_ERR(whiteout))
-			return whiteout;
-		if (PTR_ERR(whiteout) != -EMLINK) {
-			pr_warn("Failed to link whiteout - disabling whiteout inode sharing(nlink=%u, err=%lu)\n",
+		link = ovl_start_creating_temp(ofs, workdir);
+		if (IS_ERR(link))
+			return link;
+		err = ovl_do_link(ofs, ofs->whiteout, wdir, link);
+		if (!err)
+			whiteout = dget(link);
+		end_creating(link);
+		if (!err)
+			return whiteout;;
+
+		if (err != -EMLINK) {
+			pr_warn("Failed to link whiteout - disabling whiteout inode sharing(nlink=%u, err=%u)\n",
 				ofs->whiteout->d_inode->i_nlink,
-				PTR_ERR(whiteout));
+				err);
 			ofs->no_shared_whiteout = true;
 		}
 	}
@@ -132,6 +123,7 @@ int ovl_cleanup_and_whiteout(struct ovl_fs *ofs, struct dentry *dir,
 			     struct dentry *dentry)
 {
 	struct dentry *whiteout;
+	struct renamedata rd = {};
 	int err;
 	int flags = 0;
 
@@ -143,10 +135,14 @@ int ovl_cleanup_and_whiteout(struct ovl_fs *ofs, struct dentry *dir,
 	if (d_is_dir(dentry))
 		flags = RENAME_EXCHANGE;
 
-	err = ovl_lock_rename_workdir(ofs->workdir, whiteout, dir, dentry);
+	rd.mnt_idmap = ovl_upper_mnt_idmap(ofs);
+	rd.old_parent = ofs->workdir;
+	rd.new_parent = dir;
+	rd.flags = flags;
+	err = start_renaming_two_dentries(&rd, whiteout, dentry);
 	if (!err) {
-		err = ovl_do_rename(ofs, ofs->workdir, whiteout, dir, dentry, flags);
-		unlock_rename(ofs->workdir, dir);
+		err = ovl_do_rename_rd(&rd);
+		end_renaming(&rd);
 	}
 	if (err)
 		goto kill_whiteout;
@@ -191,7 +187,7 @@ struct dentry *ovl_create_real(struct ovl_fs *ofs, struct dentry *parent,
 			if (!err && ofs->casefold != ovl_dentry_casefolded(newdentry)) {
 				pr_warn_ratelimited("wrong inherited casefold (%pd2)\n",
 						    newdentry);
-				dput(newdentry);
+				end_creating(newdentry);
 				err = -EINVAL;
 			}
 			break;
@@ -241,8 +237,7 @@ struct dentry *ovl_create_real(struct ovl_fs *ofs, struct dentry *parent,
 	}
 out:
 	if (err) {
-		if (!IS_ERR(newdentry))
-			dput(newdentry);
+		end_creating(newdentry);
 		return ERR_PTR(err);
 	}
 	return newdentry;
@@ -252,11 +247,11 @@ struct dentry *ovl_create_temp(struct ovl_fs *ofs, struct dentry *workdir,
 			       struct ovl_cattr *attr)
 {
 	struct dentry *ret;
-	inode_lock_nested(workdir->d_inode, I_MUTEX_PARENT);
-	ret = ovl_create_real(ofs, workdir,
-			      ovl_lookup_temp(ofs, workdir), attr);
-	inode_unlock(workdir->d_inode);
-	return ret;
+	ret = ovl_start_creating_temp(ofs, workdir);
+	if (IS_ERR(ret))
+		return ret;
+	ret = ovl_create_real(ofs, workdir, ret, attr);
+	return end_creating_keep(ret);
 }
 
 static int ovl_set_opaque_xerr(struct dentry *dentry, struct dentry *upper,
@@ -354,19 +349,20 @@ static int ovl_create_upper(struct dentry *dentry, struct inode *inode,
 {
 	struct ovl_fs *ofs = OVL_FS(dentry->d_sb);
 	struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
-	struct inode *udir = upperdir->d_inode;
 	struct dentry *newdentry;
 	int err;
 
-	inode_lock_nested(udir, I_MUTEX_PARENT);
-	newdentry = ovl_create_real(ofs, upperdir,
-				    ovl_lookup_upper(ofs, dentry->d_name.name,
-						     upperdir, dentry->d_name.len),
-				    attr);
-	inode_unlock(udir);
+	newdentry = ovl_start_creating_upper(ofs, upperdir,
+					     &QSTR_LEN(dentry->d_name.name,
+						       dentry->d_name.len));
+	if (IS_ERR(newdentry))
+		return PTR_ERR(newdentry);
+	newdentry = ovl_create_real(ofs, upperdir, newdentry, attr);
 	if (IS_ERR(newdentry))
 		return PTR_ERR(newdentry);
 
+	end_creating_keep(newdentry);
+
 	if (ovl_type_merge(dentry->d_parent) && d_is_dir(newdentry) &&
 	    !ovl_allow_offline_changes(ofs)) {
 		/* Setting opaque here is just an optimization, allow to fail */
@@ -391,6 +387,7 @@ static struct dentry *ovl_clear_empty(struct dentry *dentry,
 	struct ovl_fs *ofs = OVL_FS(dentry->d_sb);
 	struct dentry *workdir = ovl_workdir(dentry);
 	struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
+	struct renamedata rd = {};
 	struct path upperpath;
 	struct dentry *upper;
 	struct dentry *opaquedir;
@@ -416,7 +413,11 @@ static struct dentry *ovl_clear_empty(struct dentry *dentry,
 	if (IS_ERR(opaquedir))
 		goto out;
 
-	err = ovl_lock_rename_workdir(workdir, opaquedir, upperdir, upper);
+	rd.mnt_idmap = ovl_upper_mnt_idmap(ofs);
+	rd.old_parent = workdir;
+	rd.new_parent = upperdir;
+	rd.flags = RENAME_EXCHANGE;
+	err = start_renaming_two_dentries(&rd, opaquedir, upper);
 	if (err)
 		goto out_cleanup_unlocked;
 
@@ -434,8 +435,8 @@ static struct dentry *ovl_clear_empty(struct dentry *dentry,
 	if (err)
 		goto out_cleanup;
 
-	err = ovl_do_rename(ofs, workdir, opaquedir, upperdir, upper, RENAME_EXCHANGE);
-	unlock_rename(workdir, upperdir);
+	err = ovl_do_rename_rd(&rd);
+	end_renaming(&rd);
 	if (err)
 		goto out_cleanup_unlocked;
 
@@ -448,7 +449,7 @@ static struct dentry *ovl_clear_empty(struct dentry *dentry,
 	return opaquedir;
 
 out_cleanup:
-	unlock_rename(workdir, upperdir);
+	end_renaming(&rd);
 out_cleanup_unlocked:
 	ovl_cleanup(ofs, workdir, opaquedir);
 	dput(opaquedir);
@@ -471,6 +472,7 @@ static int ovl_create_over_whiteout(struct dentry *dentry, struct inode *inode,
 	struct ovl_fs *ofs = OVL_FS(dentry->d_sb);
 	struct dentry *workdir = ovl_workdir(dentry);
 	struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
+	struct renamedata rd = {};
 	struct dentry *upper;
 	struct dentry *newdentry;
 	int err;
@@ -502,7 +504,11 @@ static int ovl_create_over_whiteout(struct dentry *dentry, struct inode *inode,
 	if (IS_ERR(newdentry))
 		goto out_dput;
 
-	err = ovl_lock_rename_workdir(workdir, newdentry, upperdir, upper);
+	rd.mnt_idmap = ovl_upper_mnt_idmap(ofs);
+	rd.old_parent = workdir;
+	rd.new_parent = upperdir;
+	rd.flags = 0;
+	err = start_renaming_two_dentries(&rd, newdentry, upper);
 	if (err)
 		goto out_cleanup_unlocked;
 
@@ -539,16 +545,16 @@ static int ovl_create_over_whiteout(struct dentry *dentry, struct inode *inode,
 		if (err)
 			goto out_cleanup;
 
-		err = ovl_do_rename(ofs, workdir, newdentry, upperdir, upper,
-				    RENAME_EXCHANGE);
-		unlock_rename(workdir, upperdir);
+		rd.flags = RENAME_EXCHANGE;
+		err = ovl_do_rename_rd(&rd);
+		end_renaming(&rd);
 		if (err)
 			goto out_cleanup_unlocked;
 
 		ovl_cleanup(ofs, workdir, upper);
 	} else {
-		err = ovl_do_rename(ofs, workdir, newdentry, upperdir, upper, 0);
-		unlock_rename(workdir, upperdir);
+		err = ovl_do_rename_rd(&rd);
+		end_renaming(&rd);
 		if (err)
 			goto out_cleanup_unlocked;
 	}
@@ -568,7 +574,7 @@ out:
 	return err;
 
 out_cleanup:
-	unlock_rename(workdir, upperdir);
+	end_renaming(&rd);
 out_cleanup_unlocked:
 	ovl_cleanup(ofs, workdir, newdentry);
 	dput(newdentry);
@@ -850,17 +856,17 @@ static int ovl_remove_upper(struct dentry *dentry, bool is_dir,
 			goto out;
 	}
 
-	inode_lock_nested(dir, I_MUTEX_PARENT);
-	upper = ovl_lookup_upper(ofs, dentry->d_name.name, upperdir,
-				 dentry->d_name.len);
+	upper = ovl_start_removing_upper(ofs, upperdir,
+					 &QSTR_LEN(dentry->d_name.name,
+						   dentry->d_name.len));
 	err = PTR_ERR(upper);
 	if (IS_ERR(upper))
-		goto out_unlock;
+		goto out_dput;
 
 	err = -ESTALE;
 	if ((opaquedir && upper != opaquedir) ||
 	    (!opaquedir && !ovl_matches_upper(dentry, upper)))
-		goto out_dput_upper;
+		goto out_unlock;
 
 	if (is_dir)
 		err = ovl_do_rmdir(ofs, dir, upper);
@@ -876,10 +882,9 @@ static int ovl_remove_upper(struct dentry *dentry, bool is_dir,
 	 */
 	if (!err)
 		d_drop(dentry);
-out_dput_upper:
-	dput(upper);
 out_unlock:
-	inode_unlock(dir);
+	end_removing(upper);
+out_dput:
 	dput(opaquedir);
 out:
 	return err;
@@ -1111,9 +1116,7 @@ static int ovl_rename(struct mnt_idmap *idmap, struct inode *olddir,
 	int err;
 	struct dentry *old_upperdir;
 	struct dentry *new_upperdir;
-	struct dentry *olddentry = NULL;
-	struct dentry *newdentry = NULL;
-	struct dentry *trap, *de;
+	struct renamedata rd = {};
 	bool old_opaque;
 	bool new_opaque;
 	bool cleanup_whiteout = false;
@@ -1123,6 +1126,7 @@ static int ovl_rename(struct mnt_idmap *idmap, struct inode *olddir,
 	bool new_is_dir = d_is_dir(new);
 	bool samedir = olddir == newdir;
 	struct dentry *opaquedir = NULL;
+	struct dentry *whiteout = NULL;
 	const struct cred *old_cred = NULL;
 	struct ovl_fs *ofs = OVL_FS(old->d_sb);
 	LIST_HEAD(list);
@@ -1220,29 +1224,21 @@ static int ovl_rename(struct mnt_idmap *idmap, struct inode *olddir,
 		}
 	}
 
-	trap = lock_rename(new_upperdir, old_upperdir);
-	if (IS_ERR(trap)) {
-		err = PTR_ERR(trap);
-		goto out_revert_creds;
-	}
+	rd.mnt_idmap = ovl_upper_mnt_idmap(ofs);
+	rd.old_parent = old_upperdir;
+	rd.new_parent = new_upperdir;
+	rd.flags = flags;
 
-	de = ovl_lookup_upper(ofs, old->d_name.name, old_upperdir,
-			      old->d_name.len);
-	err = PTR_ERR(de);
-	if (IS_ERR(de))
-		goto out_unlock;
-	olddentry = de;
+	err = start_renaming(&rd, 0,
+			     &QSTR_LEN(old->d_name.name, old->d_name.len),
+			     &QSTR_LEN(new->d_name.name, new->d_name.len));
 
-	err = -ESTALE;
-	if (!ovl_matches_upper(old, olddentry))
-		goto out_unlock;
+	if (err)
+		goto out_revert_creds;
 
-	de = ovl_lookup_upper(ofs, new->d_name.name, new_upperdir,
-			      new->d_name.len);
-	err = PTR_ERR(de);
-	if (IS_ERR(de))
+	err = -ESTALE;
+	if (!ovl_matches_upper(old, rd.old_dentry))
 		goto out_unlock;
-	newdentry = de;
 
 	old_opaque = ovl_dentry_is_opaque(old);
 	new_opaque = ovl_dentry_is_opaque(new);
@@ -1250,15 +1246,15 @@ static int ovl_rename(struct mnt_idmap *idmap, struct inode *olddir,
 	err = -ESTALE;
 	if (d_inode(new) && ovl_dentry_upper(new)) {
 		if (opaquedir) {
-			if (newdentry != opaquedir)
+			if (rd.new_dentry != opaquedir)
 				goto out_unlock;
 		} else {
-			if (!ovl_matches_upper(new, newdentry))
+			if (!ovl_matches_upper(new, rd.new_dentry))
 				goto out_unlock;
 		}
 	} else {
-		if (!d_is_negative(newdentry)) {
-			if (!new_opaque || !ovl_upper_is_whiteout(ofs, newdentry))
+		if (!d_is_negative(rd.new_dentry)) {
+			if (!new_opaque || !ovl_upper_is_whiteout(ofs, rd.new_dentry))
 				goto out_unlock;
 		} else {
 			if (flags & RENAME_EXCHANGE)
@@ -1266,19 +1262,14 @@ static int ovl_rename(struct mnt_idmap *idmap, struct inode *olddir,
 		}
 	}
 
-	if (olddentry == trap)
-		goto out_unlock;
-	if (newdentry == trap)
-		goto out_unlock;
-
-	if (olddentry->d_inode == newdentry->d_inode)
+	if (rd.old_dentry->d_inode == rd.new_dentry->d_inode)
 		goto out_unlock;
 
 	err = 0;
 	if (ovl_type_merge_or_lower(old))
 		err = ovl_set_redirect(old, samedir);
 	else if (is_dir && !old_opaque && ovl_type_merge(new->d_parent))
-		err = ovl_set_opaque_xerr(old, olddentry, -EXDEV);
+		err = ovl_set_opaque_xerr(old, rd.old_dentry, -EXDEV);
 	if (err)
 		goto out_unlock;
 
@@ -1286,18 +1277,24 @@ static int ovl_rename(struct mnt_idmap *idmap, struct inode *olddir,
 		err = ovl_set_redirect(new, samedir);
 	else if (!overwrite && new_is_dir && !new_opaque &&
 		 ovl_type_merge(old->d_parent))
-		err = ovl_set_opaque_xerr(new, newdentry, -EXDEV);
+		err = ovl_set_opaque_xerr(new, rd.new_dentry, -EXDEV);
 	if (err)
 		goto out_unlock;
 
-	err = ovl_do_rename(ofs, old_upperdir, olddentry,
-			    new_upperdir, newdentry, flags);
-	unlock_rename(new_upperdir, old_upperdir);
+	err = ovl_do_rename_rd(&rd);
+
+	if (!err && cleanup_whiteout)
+		whiteout = dget(rd.new_dentry);
+
+	end_renaming(&rd);
+
 	if (err)
 		goto out_revert_creds;
 
-	if (cleanup_whiteout)
-		ovl_cleanup(ofs, old_upperdir, newdentry);
+	if (whiteout) {
+		ovl_cleanup(ofs, old_upperdir, whiteout);
+		dput(whiteout);
+	}
 
 	if (overwrite && d_inode(new)) {
 		if (new_is_dir)
@@ -1323,14 +1320,12 @@ out_revert_creds:
 	else
 		ovl_drop_write(old);
 out:
-	dput(newdentry);
-	dput(olddentry);
 	dput(opaquedir);
 	ovl_cache_free(&list);
 	return err;
 
 out_unlock:
-	unlock_rename(new_upperdir, old_upperdir);
+	end_renaming(&rd);
 	goto out_revert_creds;
 }