xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Don't pass inode to ->d_hash() and ->d_compare()

Browse Source 
Instances either don't look at it at all (the majority of cases) or
only want it to find the superblock (which can be had as dentry->d_sb).
A few cases that want more are actually safe with dentry->d_inode -
the only precaution needed is the check that it hadn't been replaced with
NULL by rmdir() or by overwriting rename(), which case should be simply
treated as cache miss.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Linus Torvalds
2013-05-21 15:22:44 -07:00
committed by Al Viro
parent 642b704cd7
commit da53be12bb
23 changed files with 108 additions and 165 deletions
Download Patch File Download Diff File Expand all files Collapse all files

32
fs/ncpfs/dir.c
View File

@@ -73,10 +73,8 @@ const struct inode_operations ncp_dir_inode_operations =
* Dentry operations routines
*/
static int ncp_lookup_validate(struct dentry *, unsigned int);
static int ncp_hash_dentry(const struct dentry *, const struct inode *,
struct qstr *);
static int ncp_compare_dentry(const struct dentry *, const struct inode *,
const struct dentry *, const struct inode *,
static int ncp_hash_dentry(const struct dentry *, struct qstr *);
static int ncp_compare_dentry(const struct dentry *, const struct dentry *,
unsigned int, const char *, const struct qstr *);
static int ncp_delete_dentry(const struct dentry *);
@@ -119,11 +117,19 @@ static inline int ncp_case_sensitive(const struct inode *i)
/*
* Note: leave the hash unchanged if the directory
* is case-sensitive.
*
* Accessing the parent inode can be racy under RCU pathwalking.
* Use ACCESS_ONCE() to make sure we use _one_ particular inode,
* the callers will handle races.
*/
static int
ncp_hash_dentry(const struct dentry *dentry, const struct inode *inode,
struct qstr *this)
ncp_hash_dentry(const struct dentry *dentry, struct qstr *this)
{
struct inode *inode = ACCESS_ONCE(dentry->d_inode);
if (!inode)
return 0;
if (!ncp_case_sensitive(inode)) {
struct super_block *sb = dentry->d_sb;
struct nls_table *t;
@@ -140,14 +146,24 @@ ncp_hash_dentry(const struct dentry *dentry, const struct inode *inode,
return 0;
}
/*
* Accessing the parent inode can be racy under RCU pathwalking.
* Use ACCESS_ONCE() to make sure we use _one_ particular inode,
* the callers will handle races.
*/
static int
ncp_compare_dentry(const struct dentry *parent, const struct inode *pinode,
const struct dentry *dentry, const struct inode *inode,
ncp_compare_dentry(const struct dentry *parent, const struct dentry *dentry,
unsigned int len, const char *str, const struct qstr *name)
{
struct inode *pinode;
if (len != name->len)
return 1;
pinode = ACCESS_ONCE(parent->d_inode);
if (!pinode)
return 1;
if (ncp_case_sensitive(pinode))
return strncmp(str, name->name, len);