From d3e7d20befd9d07db2955015a3f294c0a0a771d3 Mon Sep 17 00:00:00 2001 From: Kaixu Xia Date: Sat, 10 Oct 2020 16:10:16 +0800 Subject: [PATCH] ext4: use the normal helper to get the actual inode Here we use the READ_ONCE to fix race conditions in ->d_compare() and ->d_hash() when they are called in RCU-walk mode, seems we can use the normal helper d_inode_rcu() to get the actual inode. Signed-off-by: Kaixu Xia Reviewed-by: Lukas Czerner Link: https://lore.kernel.org/r/1602317416-1260-1-git-send-email-kaixuxia@tencent.com Signed-off-by: Theodore Ts'o --- fs/ext4/dir.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/fs/ext4/dir.c b/fs/ext4/dir.c index 1d82336..3bf6cb8 100644 --- a/fs/ext4/dir.c +++ b/fs/ext4/dir.c @@ -674,7 +674,7 @@ static int ext4_d_compare(const struct dentry *dentry, unsigned int len, { struct qstr qstr = {.name = str, .len = len }; const struct dentry *parent = READ_ONCE(dentry->d_parent); - const struct inode *inode = READ_ONCE(parent->d_inode); + const struct inode *inode = d_inode_rcu(parent); char strbuf[DNAME_INLINE_LEN]; if (!inode || !IS_CASEFOLDED(inode) || @@ -706,7 +706,7 @@ static int ext4_d_hash(const struct dentry *dentry, struct qstr *str) { const struct ext4_sb_info *sbi = EXT4_SB(dentry->d_sb); const struct unicode_map *um = sbi->s_encoding; - const struct inode *inode = READ_ONCE(dentry->d_inode); + const struct inode *inode = d_inode_rcu(dentry); unsigned char *norm; int len, ret = 0; -- 2.7.4