struct fs_struct *fs = current->fs;
struct dentry *parent = nd->path.dentry;
+ /*
+ * It can be possible to revalidate the dentry that we started
+ * the path walk with. force_reval_path may also revalidate the
+ * dentry already committed to the nameidata.
+ */
+ if (unlikely(parent == dentry))
+ return nameidata_drop_rcu(nd);
+
BUG_ON(!(nd->flags & LOOKUP_RCU));
if (nd->root.mnt) {
spin_lock(&fs->lock);
fput(nd->intent.open.file);
}
+/*
+ * Call d_revalidate and handle filesystems that request rcu-walk
+ * to be dropped. This may be called and return in rcu-walk mode,
+ * regardless of success or error. If -ECHILD is returned, the caller
+ * must return -ECHILD back up the path walk stack so path walk may
+ * be restarted in ref-walk mode.
+ */
static int d_revalidate(struct dentry *dentry, struct nameidata *nd)
{
int status;
return 0;
if (!status) {
+ /* Don't d_invalidate in rcu-walk mode */
+ if (nameidata_drop_rcu(nd))
+ return -ECHILD;
d_invalidate(dentry);
status = -ESTALE;
}
mntput(path->mnt);
}
-static inline void path_to_nameidata(struct path *path, struct nameidata *nd)
+static inline void path_to_nameidata(const struct path *path,
+ struct nameidata *nd)
{
if (!(nd->flags & LOOKUP_RCU)) {
dput(nd->path.dentry);
}
static __always_inline int
-__do_follow_link(struct path *path, struct nameidata *nd, void **p)
+__do_follow_link(const struct path *link, struct nameidata *nd, void **p)
{
int error;
- struct dentry *dentry = path->dentry;
+ struct dentry *dentry = link->dentry;
- touch_atime(path->mnt, dentry);
+ touch_atime(link->mnt, dentry);
nd_set_link(nd, NULL);
- if (path->mnt != nd->path.mnt) {
- path_to_nameidata(path, nd);
+ if (link->mnt != nd->path.mnt) {
+ path_to_nameidata(link, nd);
nd->inode = nd->path.dentry->d_inode;
dget(dentry);
}
- mntget(path->mnt);
+ mntget(link->mnt);
nd->last_type = LAST_BIND;
*p = dentry->d_inode->i_op->follow_link(dentry, nd);
return break_lease(inode, flag);
}
-static int handle_truncate(struct path *path)
+static int handle_truncate(struct file *filp)
{
+ struct path *path = &filp->f_path;
struct inode *inode = path->dentry->d_inode;
int error = get_write_access(inode);
if (error)
if (!error) {
error = do_truncate(path->dentry, 0,
ATTR_MTIME|ATTR_CTIME|ATTR_OPEN,
- NULL);
+ filp);
}
put_write_access(inode);
return error;
}
if (!IS_ERR(filp)) {
if (will_truncate) {
- error = handle_truncate(&nd->path);
+ error = handle_truncate(filp);
if (error) {
fput(filp);
filp = ERR_PTR(error);
dir = nd->path.dentry;
case LAST_DOT:
if (need_reval_dot(dir)) {
- error = d_revalidate(nd->path.dentry, nd);
- if (!error)
- error = -ESTALE;
- if (error < 0)
+ int status = d_revalidate(nd->path.dentry, nd);
+ if (!status)
+ status = -ESTALE;
+ if (status < 0) {
+ error = status;
goto exit;
+ }
}
/* fallthrough */
case LAST_ROOT:
nd.flags = flags;
filp = do_last(&nd, &path, open_flag, acc_mode, mode, pathname);
while (unlikely(!filp)) { /* trailing symlink */
- struct path holder;
+ struct path link = path;
+ struct inode *linki = link.dentry->d_inode;
void *cookie;
error = -ELOOP;
/* S_ISDIR part is a temporary automount kludge */
- if (!(nd.flags & LOOKUP_FOLLOW) && !S_ISDIR(nd.inode->i_mode))
+ if (!(nd.flags & LOOKUP_FOLLOW) && !S_ISDIR(linki->i_mode))
goto exit_dput;
if (count++ == 32)
goto exit_dput;
* just set LAST_BIND.
*/
nd.flags |= LOOKUP_PARENT;
- error = security_inode_follow_link(path.dentry, &nd);
+ error = security_inode_follow_link(link.dentry, &nd);
if (error)
goto exit_dput;
- error = __do_follow_link(&path, &nd, &cookie);
+ error = __do_follow_link(&link, &nd, &cookie);
if (unlikely(error)) {
- if (!IS_ERR(cookie) && nd.inode->i_op->put_link)
- nd.inode->i_op->put_link(path.dentry, &nd, cookie);
+ if (!IS_ERR(cookie) && linki->i_op->put_link)
+ linki->i_op->put_link(link.dentry, &nd, cookie);
/* nd.path had been dropped */
- nd.path = path;
+ nd.path = link;
goto out_path;
}
- holder = path;
nd.flags &= ~LOOKUP_PARENT;
filp = do_last(&nd, &path, open_flag, acc_mode, mode, pathname);
- if (nd.inode->i_op->put_link)
- nd.inode->i_op->put_link(holder.dentry, &nd, cookie);
- path_put(&holder);
+ if (linki->i_op->put_link)
+ linki->i_op->put_link(link.dentry, &nd, cookie);
+ path_put(&link);
}
out:
if (nd.root.mnt)