linux-ext4 - [PATCH 03/22] ext4: Do not iput inode under running transaction in ext4

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Message-Id: <20191003220613.10791-3-jack@suse.cz>
Date:   Fri,  4 Oct 2019 00:05:49 +0200
From:   Jan Kara <jack@...e.cz>
To:     <linux-ext4@...r.kernel.org>
Cc:     Ted Tso <tytso@....edu>, Jan Kara <jack@...e.cz>,
        stable@...r.kernel.org
Subject: [PATCH 03/22] ext4: Do not iput inode under running transaction in ext4_mkdir()

When ext4_mkdir() fails to add entry into directory, it ends up dropping
freshly created inode under the running transaction and thus inode
truncation happens under that transaction. That breaks assumptions that
ext4_evict_inode() does not get called from a transaction context
(although I'm not aware of any real issue) and is completely
unnecessary. Just stop the transaction before dropping inode reference.

CC: stable@...r.kernel.org
Signed-off-by: Jan Kara <jack@...e.cz>
---
 fs/ext4/namei.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index a427d2031a8d..9c872a33aea7 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -2781,8 +2781,9 @@ static int ext4_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 		clear_nlink(inode);
 		unlock_new_inode(inode);
 		ext4_mark_inode_dirty(handle, inode);
+		ext4_journal_stop(handle);
 		iput(inode);
-		goto out_stop;
+		goto out_retry;
 	}
 	ext4_inc_count(handle, dir);
 	ext4_update_dx_flag(dir);
@@ -2796,6 +2797,7 @@ static int ext4_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 out_stop:
 	if (handle)
 		ext4_journal_stop(handle);
+out_retry:
 	if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
 		goto retry;
 	return err;
-- 
2.16.4