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split do_revalidate() into RCU and non-RCU cases

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fixing oopsen in lookup_one_len()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2011-02-15 01:32:55 -05:00
parent 24643087e7
commit f5e1c1c1af
1 changed files with 30 additions and 17 deletions
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47
fs/namei.c
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@ -592,12 +592,10 @@ static int d_revalidate(struct dentry *dentry, struct nameidata *nd)
return status;
}
static inline struct dentry *
static struct dentry *
do_revalidate(struct dentry *dentry, struct nameidata *nd)
{
int status;
status = d_revalidate(dentry, nd);
int status = d_revalidate(dentry, nd);
if (unlikely(status <= 0)) {
/*
* The dentry failed validation.
@ -606,24 +604,39 @@ do_revalidate(struct dentry *dentry, struct nameidata *nd)
* to return a fail status.
*/
if (status < 0) {
/* If we're in rcu-walk, we don't have a ref */
if (!(nd->flags & LOOKUP_RCU))
dput(dentry);
dput(dentry);
dentry = ERR_PTR(status);
} else {
/* Don't d_invalidate in rcu-walk mode */
if (nameidata_dentry_drop_rcu_maybe(nd, dentry))
return ERR_PTR(-ECHILD);
if (!d_invalidate(dentry)) {
dput(dentry);
dentry = NULL;
}
} else if (!d_invalidate(dentry)) {
dput(dentry);
dentry = NULL;
}
}
return dentry;
}
static inline struct dentry *
do_revalidate_rcu(struct dentry *dentry, struct nameidata *nd)
{
int status = dentry->d_op->d_revalidate(dentry, nd);
if (likely(status > 0))
return dentry;
if (status == -ECHILD) {
if (nameidata_dentry_drop_rcu(nd, dentry))
return ERR_PTR(-ECHILD);
return do_revalidate(dentry, nd);
}
if (status < 0)
return ERR_PTR(status);
/* Don't d_invalidate in rcu-walk mode */
if (nameidata_dentry_drop_rcu(nd, dentry))
return ERR_PTR(-ECHILD);
if (!d_invalidate(dentry)) {
dput(dentry);
dentry = NULL;
}
return dentry;
}
static inline int need_reval_dot(struct dentry *dentry)
{
if (likely(!(dentry->d_flags & DCACHE_OP_REVALIDATE)))
@ -1260,7 +1273,7 @@ static int do_lookup(struct nameidata *nd, struct qstr *name,
nd->seq = seq;
if (unlikely(dentry->d_flags & DCACHE_OP_REVALIDATE)) {
dentry = do_revalidate(dentry, nd);
dentry = do_revalidate_rcu(dentry, nd);
if (!dentry)
goto need_lookup;
if (IS_ERR(dentry))