linux-kernel - [PATCH 03/16] vfs: don't evict uninitialized inode

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Message-Id: <20180729220453.13431-3-viro@ZenIV.linux.org.uk>
Date:   Sun, 29 Jul 2018 23:04:40 +0100
From:   Al Viro <viro@...IV.linux.org.uk>
To:     linux-fsdevel@...r.kernel.org
Cc:     Linus Torvalds <torvalds@...ux-foundation.org>,
        linux-kernel@...r.kernel.org, Miklos Szeredi <mszeredi@...hat.com>
Subject: [PATCH 03/16] vfs: don't evict uninitialized inode

From: Miklos Szeredi <mszeredi@...hat.com>

iput() ends up calling ->evict() on new inode, which is not yet initialized
by owning fs.  So use destroy_inode() instead.

Add to sb->s_inodes list only if inode is not in I_CREATING state (meaning
that it wasn't allocated with new_inode(), which already does the
insertion).

Reported-by: Al Viro <viro@...iv.linux.org.uk>
Signed-off-by: Miklos Szeredi <mszeredi@...hat.com>
Fixes: 80ea09a002bf ("vfs: factor out inode_insert5()")
Signed-off-by: Al Viro <viro@...iv.linux.org.uk>
---
 fs/inode.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/fs/inode.c b/fs/inode.c
index 04dd7e0d5142..0aa5b29b6f87 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -1050,6 +1050,7 @@ struct inode *inode_insert5(struct inode *inode, unsigned long hashval,
 {
 	struct hlist_head *head = inode_hashtable + hash(inode->i_sb, hashval);
 	struct inode *old;
+	bool creating = inode->i_state & I_CREATING;
 
 again:
 	spin_lock(&inode_hash_lock);
@@ -1083,6 +1084,8 @@ struct inode *inode_insert5(struct inode *inode, unsigned long hashval,
 	inode->i_state |= I_NEW;
 	hlist_add_head(&inode->i_hash, head);
 	spin_unlock(&inode->i_lock);
+	if (!creating)
+		inode_sb_list_add(inode);
 unlock:
 	spin_unlock(&inode_hash_lock);
 
@@ -1117,12 +1120,13 @@ struct inode *iget5_locked(struct super_block *sb, unsigned long hashval,
 	struct inode *inode = ilookup5(sb, hashval, test, data);
 
 	if (!inode) {
-		struct inode *new = new_inode(sb);
+		struct inode *new = alloc_inode(sb);
 
 		if (new) {
+			new->i_state = 0;
 			inode = inode_insert5(new, hashval, test, set, data);
 			if (unlikely(inode != new))
-				iput(new);
+				destroy_inode(new);
 		}
 	}
 	return inode;
-- 
2.11.0