linux-ext4 - [PATCH AUTOSEL 5.10 36/39] ext4: do not iput inode under running transaction in ext4

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Date:   Thu, 25 Mar 2021 07:25:55 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     "zhangyi (F)" <yi.zhang@...wei.com>, Theodore Ts'o <tytso@....edu>,
        Sasha Levin <sashal@...nel.org>, linux-ext4@...r.kernel.org
Subject: [PATCH AUTOSEL 5.10 36/39] ext4: do not iput inode under running transaction in ext4_rename()

From: "zhangyi (F)" <yi.zhang@...wei.com>

[ Upstream commit 5dccdc5a1916d4266edd251f20bbbb113a5c495f ]

In ext4_rename(), when RENAME_WHITEOUT failed to add new entry into
directory, it ends up dropping new created whiteout inode under the
running transaction. After commit <9b88f9fb0d2> ("ext4: Do not iput inode
under running transaction"), we follow the assumptions that evict() does
not get called from a transaction context but in ext4_rename() it breaks
this suggestion. Although it's not a real problem, better to obey it, so
this patch add inode to orphan list and stop transaction before final
iput().

Signed-off-by: zhangyi (F) <yi.zhang@...wei.com>
Link: https://lore.kernel.org/r/20210303131703.330415-2-yi.zhang@huawei.com
Signed-off-by: Theodore Ts'o <tytso@....edu>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 fs/ext4/namei.c | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index 14783f7dcbe9..29e7da143106 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -3763,14 +3763,14 @@ static int ext4_rename(struct inode *old_dir, struct dentry *old_dentry,
 	 */
 	retval = -ENOENT;
 	if (!old.bh || le32_to_cpu(old.de->inode) != old.inode->i_ino)
-		goto end_rename;
+		goto release_bh;
 
 	new.bh = ext4_find_entry(new.dir, &new.dentry->d_name,
 				 &new.de, &new.inlined);
 	if (IS_ERR(new.bh)) {
 		retval = PTR_ERR(new.bh);
 		new.bh = NULL;
-		goto end_rename;
+		goto release_bh;
 	}
 	if (new.bh) {
 		if (!new.inode) {
@@ -3787,15 +3787,13 @@ static int ext4_rename(struct inode *old_dir, struct dentry *old_dentry,
 		handle = ext4_journal_start(old.dir, EXT4_HT_DIR, credits);
 		if (IS_ERR(handle)) {
 			retval = PTR_ERR(handle);
-			handle = NULL;
-			goto end_rename;
+			goto release_bh;
 		}
 	} else {
 		whiteout = ext4_whiteout_for_rename(&old, credits, &handle);
 		if (IS_ERR(whiteout)) {
 			retval = PTR_ERR(whiteout);
-			whiteout = NULL;
-			goto end_rename;
+			goto release_bh;
 		}
 	}
 
@@ -3929,16 +3927,18 @@ static int ext4_rename(struct inode *old_dir, struct dentry *old_dentry,
 			ext4_setent(handle, &old,
 				old.inode->i_ino, old_file_type);
 			drop_nlink(whiteout);
+			ext4_orphan_add(handle, whiteout);
 		}
 		unlock_new_inode(whiteout);
+		ext4_journal_stop(handle);
 		iput(whiteout);
-
+	} else {
+		ext4_journal_stop(handle);
 	}
+release_bh:
 	brelse(old.dir_bh);
 	brelse(old.bh);
 	brelse(new.bh);
-	if (handle)
-		ext4_journal_stop(handle);
 	return retval;
 }
 
-- 
2.30.1