For a merge dir that was copied up before v4.12 or that was hand crafted
offline (e.g. mkdir {upper/lower}/dir), upper dir does not contain the
'trusted.overlay.origin' xattr. In that case, stat(2) on the merge dir
returns the lower dir st_ino, but getdents(2) returns the upper dir d_ino.
After this change, on merge dir lookup, missing origin xattr on upper
dir will be fixed and 'impure' xattr will be fixed on parent of the legacy
merge dir.
Suggested-by: zhangyi (F) <yi.zhang@xxxxxxxxxx>
Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx>
---
Zhangyi,
A slightly differnt patch. This time with ovl_want_write()
and using different helpers.
Please re-review and test.
Thanks,
Amir.
fs/overlayfs/copy_up.c | 4 ++--
fs/overlayfs/namei.c | 33 +++++++++++++++++++++++++++++++++
fs/overlayfs/overlayfs.h | 2 ++
3 files changed, 37 insertions(+), 2 deletions(-)
diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c
index eb3b8d39fb61..206ececd5ae7 100644
--- a/fs/overlayfs/copy_up.c
+++ b/fs/overlayfs/copy_up.c
@@ -288,8 +288,8 @@ struct ovl_fh *ovl_encode_fh(struct dentry *lower, bool is_upper)
return fh;
}
-static int ovl_set_origin(struct dentry *dentry, struct dentry *lower,
- struct dentry *upper)
+int ovl_set_origin(struct dentry *dentry, struct dentry *lower,
+ struct dentry *upper)
{
const struct ovl_fh *fh = NULL;
int err;
diff --git a/fs/overlayfs/namei.c b/fs/overlayfs/namei.c
index 9cf15463754c..71db9a966d88 100644
--- a/fs/overlayfs/namei.c
+++ b/fs/overlayfs/namei.c
@@ -584,6 +584,27 @@ static int ovl_find_layer(struct ovl_fs *ofs, struct ovl_path *path)
return i;
}
+/* Fix missing 'origin' xattr */
+static int ovl_fix_origin(struct dentry *dentry, struct dentry *lower,
+ struct dentry *upper)
+{
+ int err;
+
+ if (ovl_check_origin_xattr(upper))
+ return 0;
+
+ err = ovl_want_write(dentry);
+ if (err)
+ return err;
+
+ err = ovl_set_origin(dentry, lower, upper);
+ if (!err)
+ err = ovl_set_impure(dentry->d_parent, upper->d_parent);
+
+ ovl_drop_write(dentry);
+ return err;
+}
+
struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
unsigned int flags)
{
@@ -674,6 +695,18 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
if (!this)
continue;
+ /*
+ * 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) {
+ err = ovl_fix_origin(dentry, this, upperdentry);
+ if (err) {
+ dput(this);
+ goto out_put;
+ }
+ }
+
stack[ctr].dentry = this;
stack[ctr].layer = lower.layer;
ctr++;
diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
index b489099ccd49..d1cfa69c98b5 100644
--- a/fs/overlayfs/overlayfs.h
+++ b/fs/overlayfs/overlayfs.h
@@ -322,3 +322,5 @@ int ovl_copy_up_flags(struct dentry *dentry, int flags);
int ovl_copy_xattr(struct dentry *old, struct dentry *new);
int ovl_set_attr(struct dentry *upper, struct kstat *stat);
struct ovl_fh *ovl_encode_fh(struct dentry *lower, bool is_upper);
+int ovl_set_origin(struct dentry *dentry, struct dentry *lower,
+ struct dentry *upper);
--
2.7.4
--
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