fs/9p: Always ask new inode in lookup for cache mode disabled
This make sure we don't end up reusing the unlinked inode object.
The ideal way is to use inode i_generation. But i_generation is
not available in userspace always.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
diff --git a/fs/9p/vfs_inode.c b/fs/9p/vfs_inode.c
index 9e3ea6c..e3c03db 100644
--- a/fs/9p/vfs_inode.c
+++ b/fs/9p/vfs_inode.c
@@ -825,6 +825,7 @@
struct dentry *v9fs_vfs_lookup(struct inode *dir, struct dentry *dentry,
struct nameidata *nameidata)
{
+ struct dentry *res;
struct super_block *sb;
struct v9fs_session_info *v9ses;
struct p9_fid *dfid, *fid;
@@ -856,22 +857,35 @@
return ERR_PTR(result);
}
-
- inode = v9fs_get_inode_from_fid(v9ses, fid, dir->i_sb);
+ /*
+ * Make sure we don't use a wrong inode due to parallel
+ * unlink. For cached mode create calls request for new
+ * inode. But with cache disabled, lookup should do this.
+ */
+ if (v9ses->cache)
+ inode = v9fs_get_inode_from_fid(v9ses, fid, dir->i_sb);
+ else
+ inode = v9fs_get_new_inode_from_fid(v9ses, fid, dir->i_sb);
if (IS_ERR(inode)) {
result = PTR_ERR(inode);
inode = NULL;
goto error;
}
-
result = v9fs_fid_add(dentry, fid);
if (result < 0)
goto error_iput;
-
inst_out:
- d_add(dentry, inode);
- return NULL;
-
+ /*
+ * If we had a rename on the server and a parallel lookup
+ * for the new name, then make sure we instantiate with
+ * the new name. ie look up for a/b, while on server somebody
+ * moved b under k and client parallely did a lookup for
+ * k/b.
+ */
+ res = d_materialise_unique(dentry, inode);
+ if (!IS_ERR(res))
+ return res;
+ result = PTR_ERR(res);
error_iput:
iput(inode);
error: