Commit d3e7d20b authored by Kaixu Xia's avatar Kaixu Xia Committed by Theodore Ts'o
Browse files

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: default avatarKaixu Xia <kaixuxia@tencent.com>
Reviewed-by: default avatarLukas Czerner <lczerner@redhat.com>
Link: https://lore.kernel.org/r/1602317416-1260-1-git-send-email-kaixuxia@tencent.com


Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
parent d1e18b88

fs/ext4/dir.c

+2 −2
Original line number Diff line number Diff line
@@ -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;

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