ovl: check whiteout on lowest layer as well
Not checking whiteouts on lowest layer was an optimization (there's nothing
to white out there), but it could result in inconsitent behavior when a
layer previously used as upper/middle is later used as lowest.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
diff --git a/fs/overlayfs/readdir.c b/fs/overlayfs/readdir.c
index dfef6ca..9df848f 100644
--- a/fs/overlayfs/readdir.c
+++ b/fs/overlayfs/readdir.c
@@ -80,23 +80,50 @@
return NULL;
}
-static struct ovl_cache_entry *ovl_cache_entry_new(const char *name, int len,
+static struct ovl_cache_entry *ovl_cache_entry_new(struct dentry *dir,
+ const char *name, int len,
u64 ino, unsigned int d_type)
{
struct ovl_cache_entry *p;
size_t size = offsetof(struct ovl_cache_entry, name[len + 1]);
p = kmalloc(size, GFP_KERNEL);
- if (p) {
- memcpy(p->name, name, len);
- p->name[len] = '\0';
- p->len = len;
- p->type = d_type;
- p->ino = ino;
- p->is_whiteout = false;
- p->is_cursor = false;
- }
+ if (!p)
+ return NULL;
+ memcpy(p->name, name, len);
+ p->name[len] = '\0';
+ p->len = len;
+ p->type = d_type;
+ p->ino = ino;
+ p->is_whiteout = false;
+ p->is_cursor = false;
+
+ if (d_type == DT_CHR) {
+ struct dentry *dentry;
+ const struct cred *old_cred;
+ struct cred *override_cred;
+
+ override_cred = prepare_creds();
+ if (!override_cred) {
+ kfree(p);
+ return NULL;
+ }
+
+ /*
+ * CAP_DAC_OVERRIDE for lookup
+ */
+ cap_raise(override_cred->cap_effective, CAP_DAC_OVERRIDE);
+ old_cred = override_creds(override_cred);
+
+ dentry = lookup_one_len(name, dir, len);
+ if (!IS_ERR(dentry)) {
+ p->is_whiteout = ovl_is_whiteout(dentry);
+ dput(dentry);
+ }
+ revert_creds(old_cred);
+ put_cred(override_cred);
+ }
return p;
}
@@ -123,36 +150,10 @@
return 0;
}
- p = ovl_cache_entry_new(name, len, ino, d_type);
+ p = ovl_cache_entry_new(rdd->dir, name, len, ino, d_type);
if (p == NULL)
return -ENOMEM;
- if (d_type == DT_CHR) {
- struct dentry *dentry;
- const struct cred *old_cred;
- struct cred *override_cred;
-
- override_cred = prepare_creds();
- if (!override_cred) {
- kfree(p);
- return -ENOMEM;
- }
-
- /*
- * CAP_DAC_OVERRIDE for lookup
- */
- cap_raise(override_cred->cap_effective, CAP_DAC_OVERRIDE);
- old_cred = override_creds(override_cred);
-
- dentry = lookup_one_len(name, rdd->dir, len);
- if (!IS_ERR(dentry)) {
- p->is_whiteout = ovl_is_whiteout(dentry);
- dput(dentry);
- }
- revert_creds(old_cred);
- put_cred(override_cred);
- }
-
list_add_tail(&p->l_node, rdd->list);
rb_link_node(&p->node, parent, newp);
rb_insert_color(&p->node, &rdd->root);
@@ -170,7 +171,7 @@
if (p) {
list_move_tail(&p->l_node, &rdd->middle);
} else {
- p = ovl_cache_entry_new(name, namelen, ino, d_type);
+ p = ovl_cache_entry_new(rdd->dir, name, namelen, ino, d_type);
if (p == NULL)
rdd->err = -ENOMEM;
else
@@ -229,6 +230,7 @@
if (IS_ERR(realfile))
return PTR_ERR(realfile);
+ rdd->dir = realpath->dentry;
rdd->ctx.pos = 0;
do {
rdd->count = 0;
@@ -274,7 +276,6 @@
next = ovl_path_next(idx, dentry, &realpath);
if (next != -1) {
- rdd.dir = realpath.dentry;
err = ovl_dir_read(&realpath, &rdd);
if (err)
break;