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path: root/fs/overlayfs/namei.c
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-rw-r--r--fs/overlayfs/namei.c112
1 files changed, 95 insertions, 17 deletions
diff --git a/fs/overlayfs/namei.c b/fs/overlayfs/namei.c
index ebc377bd010a..f562bbb59ddb 100644
--- a/fs/overlayfs/namei.c
+++ b/fs/overlayfs/namei.c
@@ -24,6 +24,7 @@ struct ovl_lookup_data {
bool stop;
bool last;
char *redirect;
+ bool metacopy;
};
static int ovl_check_redirect(struct dentry *dentry, struct ovl_lookup_data *d,
@@ -252,16 +253,25 @@ static int ovl_lookup_single(struct dentry *base, struct ovl_lookup_data *d,
d->stop = d->opaque = true;
goto put_and_out;
}
- if (!d_can_lookup(this)) {
+ /*
+ * This dentry should be a regular file if previous layer lookup
+ * found a metacopy dentry.
+ */
+ if (last_element && d->metacopy && !d_is_reg(this)) {
d->stop = true;
- if (d->is_dir)
+ goto put_and_out;
+ }
+ if (!d_can_lookup(this)) {
+ if (d->is_dir || !last_element) {
+ d->stop = true;
goto put_and_out;
+ }
+ err = ovl_check_metacopy_xattr(this);
+ if (err < 0)
+ goto out_err;
- /*
- * NB: handle failure to lookup non-last element when non-dir
- * redirects become possible
- */
- WARN_ON(!last_element);
+ d->metacopy = err;
+ d->stop = !d->metacopy;
goto out;
}
if (last_element)
@@ -823,7 +833,7 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
struct ovl_entry *poe = dentry->d_parent->d_fsdata;
struct ovl_entry *roe = dentry->d_sb->s_root->d_fsdata;
- struct ovl_path *stack = NULL;
+ struct ovl_path *stack = NULL, *origin_path = NULL;
struct dentry *upperdir, *upperdentry = NULL;
struct dentry *origin = NULL;
struct dentry *index = NULL;
@@ -834,6 +844,7 @@ 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,
@@ -841,6 +852,7 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
.stop = false,
.last = ofs->config.redirect_follow ? false : !poe->numlower,
.redirect = NULL,
+ .metacopy = false,
};
if (dentry->d_name.len > ofs->namelen)
@@ -859,7 +871,9 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
goto out;
}
if (upperdentry && !d.is_dir) {
- BUG_ON(!d.stop || d.redirect);
+ unsigned int origin_ctr = 0;
+
+ BUG_ON(d.redirect);
/*
* Lookup copy up origin by decoding origin file handle.
* We may get a disconnected dentry, which is fine,
@@ -870,9 +884,13 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
* number - it's the same as if we held a reference
* to a dentry in lower layer that was moved under us.
*/
- err = ovl_check_origin(ofs, upperdentry, &stack, &ctr);
+ err = ovl_check_origin(ofs, upperdentry, &origin_path,
+ &origin_ctr);
if (err)
goto out_put_upper;
+
+ if (d.metacopy)
+ metacopy = true;
}
if (d.redirect) {
@@ -913,7 +931,7 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
* If no origin fh is stored in upper of a merge dir, store fh
* of lower dir and set upper parent "impure".
*/
- if (upperdentry && !ctr && !ofs->noxattr) {
+ if (upperdentry && !ctr && !ofs->noxattr && d.is_dir) {
err = ovl_fix_origin(dentry, this, upperdentry);
if (err) {
dput(this);
@@ -925,18 +943,35 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
* When "verify_lower" feature is enabled, do not merge with a
* lower dir that does not match a stored origin xattr. In any
* case, only verified origin is used for index lookup.
+ *
+ * For non-dir dentry, if index=on, then ensure origin
+ * matches the dentry found using path based lookup,
+ * otherwise error out.
*/
- if (upperdentry && !ctr && ovl_verify_lower(dentry->d_sb)) {
+ if (upperdentry && !ctr &&
+ ((d.is_dir && ovl_verify_lower(dentry->d_sb)) ||
+ (!d.is_dir && ofs->config.index && origin_path))) {
err = ovl_verify_origin(upperdentry, this, false);
if (err) {
dput(this);
- break;
+ if (d.is_dir)
+ break;
+ goto out_put;
}
-
- /* Bless lower dir as verified origin */
origin = this;
}
+ if (d.metacopy)
+ metacopy = true;
+ /*
+ * Do not store intermediate metacopy dentries in chain,
+ * except top most lower metacopy dentry
+ */
+ if (d.metacopy && ctr) {
+ dput(this);
+ continue;
+ }
+
stack[ctr].dentry = this;
stack[ctr].layer = lower.layer;
ctr++;
@@ -968,13 +1003,48 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
}
}
+ if (metacopy) {
+ /*
+ * Found a metacopy dentry but did not find corresponding
+ * data dentry
+ */
+ if (d.metacopy) {
+ err = -EIO;
+ goto out_put;
+ }
+
+ err = -EPERM;
+ if (!ofs->config.metacopy) {
+ pr_warn_ratelimited("overlay: refusing to follow metacopy origin for (%pd2)\n",
+ dentry);
+ goto out_put;
+ }
+ } else if (!d.is_dir && upperdentry && !ctr && origin_path) {
+ if (WARN_ON(stack != NULL)) {
+ err = -EIO;
+ goto out_put;
+ }
+ stack = origin_path;
+ ctr = 1;
+ origin_path = NULL;
+ }
+
/*
* Lookup index by lower inode and verify it matches upper inode.
* We only trust dir index if we verified that lower dir matches
* origin, otherwise dir index entries may be inconsistent and we
- * ignore them. Always lookup index of non-dir and non-upper.
+ * ignore them.
+ *
+ * For non-dir upper metacopy dentry, we already set "origin" if we
+ * verified that lower matched upper origin. If upper origin was
+ * not present (because lower layer did not support fh encode/decode),
+ * or indexing is not enabled, do not set "origin" and skip looking up
+ * index. This case should be handled in same way as a non-dir upper
+ * without ORIGIN is handled.
+ *
+ * Always lookup index of non-dir non-metacopy and non-upper.
*/
- if (ctr && (!upperdentry || !d.is_dir))
+ if (ctr && (!upperdentry || (!d.is_dir && !metacopy)))
origin = stack[0].dentry;
if (origin && ovl_indexdir(dentry->d_sb) &&
@@ -1019,6 +1089,10 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
}
revert_creds(old_cred);
+ if (origin_path) {
+ dput(origin_path->dentry);
+ kfree(origin_path);
+ }
dput(index);
kfree(stack);
kfree(d.redirect);
@@ -1033,6 +1107,10 @@ out_put:
dput(stack[i].dentry);
kfree(stack);
out_put_upper:
+ if (origin_path) {
+ dput(origin_path->dentry);
+ kfree(origin_path);
+ }
dput(upperdentry);
kfree(upperredirect);
out:
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-16 03:04:09 +0000