9p: if v9fs_fid_lookup() gets to asking server, it'd better have hashed dentry

... otherwise the path we'd built isn't worth much.  Don't accept such fids
obtained from paths unless dentry is still alived by the end of the work.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2013-02-28 01:50:20 -05:00
Родитель a3b2157e72
Коммит 5e608671df
1 изменённых файлов: 17 добавлений и 3 удалений

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@ -41,10 +41,15 @@
*
*/
static inline void __add_fid(struct dentry *dentry, struct p9_fid *fid)
{
hlist_add_head(&fid->dlist, (struct hlist_head *)&dentry->d_fsdata);
}
void v9fs_fid_add(struct dentry *dentry, struct p9_fid *fid)
{
spin_lock(&dentry->d_lock);
hlist_add_head(&fid->dlist, (struct hlist_head *)&dentry->d_fsdata);
__add_fid(dentry, fid);
spin_unlock(&dentry->d_lock);
}
@ -198,8 +203,17 @@ static struct p9_fid *v9fs_fid_lookup_with_uid(struct dentry *dentry,
}
kfree(wnames);
fid_out:
if (!IS_ERR(fid))
v9fs_fid_add(dentry, fid);
if (!IS_ERR(fid)) {
spin_lock(&dentry->d_lock);
if (d_unhashed(dentry)) {
spin_unlock(&dentry->d_lock);
p9_client_clunk(fid);
fid = ERR_PTR(-ENOENT);
} else {
__add_fid(dentry, fid);
spin_unlock(&dentry->d_lock);
}
}
err_out:
up_read(&v9ses->rename_sem);
return fid;