ovl: hash overlay non-dir inodes by copy up origin
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
index 35bb956..d9fe07d 100644
--- a/fs/overlayfs/inode.c
+++ b/fs/overlayfs/inode.c
@@ -467,6 +467,25 @@
return 0;
}
+static bool ovl_verify_inode(struct inode *inode, struct dentry *lowerdentry,
+ struct dentry *upperdentry)
+{
+ struct inode *lowerinode = lowerdentry ? d_inode(lowerdentry) : NULL;
+
+ /* Lower (origin) inode must match, even if NULL */
+ if (ovl_inode_lower(inode) != lowerinode)
+ return false;
+
+ /*
+ * Allow non-NULL __upperdentry in inode even if upperdentry is NULL.
+ * This happens when finding a lower alias for a copied up hard link.
+ */
+ if (upperdentry && ovl_inode_upper(inode) != d_inode(upperdentry))
+ return false;
+
+ return true;
+}
+
struct inode *ovl_get_inode(struct dentry *dentry, struct dentry *upperdentry)
{
struct dentry *lowerdentry = ovl_dentry_lower(dentry);
@@ -476,12 +495,25 @@
if (!realinode)
realinode = d_inode(lowerdentry);
- if (upperdentry && !d_is_dir(upperdentry)) {
- inode = iget5_locked(dentry->d_sb, (unsigned long) realinode,
- ovl_inode_test, ovl_inode_set, realinode);
+ if (!S_ISDIR(realinode->i_mode) &&
+ (upperdentry || (lowerdentry && ovl_indexdir(dentry->d_sb)))) {
+ struct inode *key = d_inode(lowerdentry ?: upperdentry);
+
+ inode = iget5_locked(dentry->d_sb, (unsigned long) key,
+ ovl_inode_test, ovl_inode_set, key);
if (!inode)
- goto out;
+ goto out_nomem;
if (!(inode->i_state & I_NEW)) {
+ /*
+ * Verify that the underlying files stored in the inode
+ * match those in the dentry.
+ */
+ if (!ovl_verify_inode(inode, lowerdentry, upperdentry)) {
+ iput(inode);
+ inode = ERR_PTR(-ESTALE);
+ goto out;
+ }
+
dput(upperdentry);
goto out;
}
@@ -490,7 +522,7 @@
} else {
inode = new_inode(dentry->d_sb);
if (!inode)
- goto out;
+ goto out_nomem;
}
ovl_fill_inode(inode, realinode->i_mode, realinode->i_rdev);
ovl_inode_init(inode, upperdentry, lowerdentry);
@@ -502,4 +534,8 @@
unlock_new_inode(inode);
out:
return inode;
+
+out_nomem:
+ inode = ERR_PTR(-ENOMEM);
+ goto out;
}