During lookup, check for presence of OVL_XATTR_METACOPY and if present,
set OVL_METACOPY bit in flags.
Signed-off-by: Vivek Goyal <vgoyal@xxxxxxxxxx>
---
fs/overlayfs/namei.c | 40 ++++++++++++++++++++++++++++++++++++++++
1 file changed, 40 insertions(+)
diff --git a/fs/overlayfs/namei.c b/fs/overlayfs/namei.c
index 88ff1daeb3d7..d32da041f4bf 100644
--- a/fs/overlayfs/namei.c
+++ b/fs/overlayfs/namei.c
@@ -26,6 +26,24 @@ struct ovl_lookup_data {
char *redirect;
};
+/* err < 0, 0 if no metacopy xattr, 1 if metacopy xattr found */
+static int ovl_check_metacopy(struct dentry *dentry)
+{
+ int res;
+
+ res = vfs_getxattr(dentry, OVL_XATTR_METACOPY, NULL, 0);
+ if (res < 0) {
+ if (res == -ENODATA || res == -EOPNOTSUPP)
+ return 0;
+ goto out;
+ }
+
+ return 1;
+out:
+ pr_warn_ratelimited("overlayfs: failed to get metacopy (%i)\n", res);
+ return res;
+}
+
static int ovl_check_redirect(struct dentry *dentry, struct ovl_lookup_data *d,
size_t prelen, const char *post)
{
@@ -594,6 +612,7 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
struct dentry *this;
unsigned int i;
int err;
+ bool metacopy = false;
struct ovl_lookup_data d = {
.name = dentry->d_name,
.is_dir = false,
@@ -634,6 +653,12 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
roe->numlower, &stack, &ctr);
if (err)
goto out;
+
+ err = ovl_check_metacopy(upperdentry);
+ if (err < 0)
+ goto out;
+ if (err == 1)
+ metacopy = true;
}
if (d.redirect) {
@@ -719,6 +744,19 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
OVL_I(inode)->redirect = upperredirect;
if (index)
ovl_set_flag(OVL_INDEX, inode);
+
+ if (metacopy) {
+ /*
+ * Found an upper with metacopy set but at the same
+ * time there is no lower dentry. Something is not
+ * right.
+ */
+ if (!ctr) {
+ err = -ESTALE;
+ goto out_put_inode;
+ }
+ ovl_set_flag(OVL_METACOPY, inode);
+ }
}
revert_creds(old_cred);
@@ -729,6 +767,8 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
return NULL;
+out_put_inode:
+ iput(inode);
out_free_oe:
dentry->d_fsdata = NULL;
kfree(oe);
--
2.13.5
--
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