ovl: Copy up meta inode data from lowest data inode

So far lower could not be a meta inode.  So whenever it was time to copy up
data of a meta inode, we could copy it up from top most lower dentry.

But now lower itself can be a metacopy inode.  That means data copy up
needs to take place from a data inode in metacopy inode chain.  Find lower
data inode in the chain and use that for data copy up.

Introduced a helper called ovl_path_lowerdata() to find the lower data
inode chain.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c
index 7e6664d6643d152d2158892295473d8a60aa6fc6..d9a8d9291358d8de06cfb599e80c651acb8d4a27 100644 (file)
--- a/fs/overlayfs/copy_up.c
+++ b/fs/overlayfs/copy_up.c
@@ -519,13 +519,14 @@ static int ovl_copy_up_inode(struct ovl_copy_up_ctx *c, struct dentry *temp)
        }
 
        if (S_ISREG(c->stat.mode) && !c->metacopy) {
-               struct path upperpath;
+               struct path upperpath, datapath;
 
                ovl_path_upper(c->dentry, &upperpath);
                BUG_ON(upperpath.dentry != NULL);
                upperpath.dentry = temp;
 
-               err = ovl_copy_up_data(&c->lowerpath, &upperpath, c->stat.size);
+               ovl_path_lowerdata(c->dentry, &datapath);
+               err = ovl_copy_up_data(&datapath, &upperpath, c->stat.size);
                if (err)
                        return err;
        }
@@ -706,14 +707,18 @@ static bool ovl_need_meta_copy_up(struct dentry *dentry, umode_t mode,
 /* Copy up data of an inode which was copied up metadata only in the past. */
 static int ovl_copy_up_meta_inode_data(struct ovl_copy_up_ctx *c)
 {
-       struct path upperpath;
+       struct path upperpath, datapath;
        int err;
 
        ovl_path_upper(c->dentry, &upperpath);
        if (WARN_ON(upperpath.dentry == NULL))
                return -EIO;
 
-       err = ovl_copy_up_data(&c->lowerpath, &upperpath, c->stat.size);
+       ovl_path_lowerdata(c->dentry, &datapath);
+       if (WARN_ON(datapath.dentry == NULL))
+               return -EIO;
+
+       err = ovl_copy_up_data(&datapath, &upperpath, c->stat.size);
        if (err)
                return err;
 

diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
index 2de8e11db81a6d51cc51d5046c6407f204472819..a59c546c10cfe8cc5edd1a22a15cc15829da27e6 100644 (file)
--- a/fs/overlayfs/overlayfs.h
+++ b/fs/overlayfs/overlayfs.h
@@ -217,6 +217,7 @@ bool ovl_dentry_weird(struct dentry *dentry);
 enum ovl_path_type ovl_path_type(struct dentry *dentry);
 void ovl_path_upper(struct dentry *dentry, struct path *path);
 void ovl_path_lower(struct dentry *dentry, struct path *path);
+void ovl_path_lowerdata(struct dentry *dentry, struct path *path);
 enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path);
 struct dentry *ovl_dentry_upper(struct dentry *dentry);
 struct dentry *ovl_dentry_lower(struct dentry *dentry);

diff --git a/fs/overlayfs/util.c b/fs/overlayfs/util.c
index ab9a8fae0f99d45adf6e34d512a893d079147dd2..32ff67fa0bfb92eb2ea2bd57cbaffbbf0fe17acf 100644 (file)
--- a/fs/overlayfs/util.c
+++ b/fs/overlayfs/util.c
@@ -164,6 +164,18 @@ void ovl_path_lower(struct dentry *dentry, struct path *path)
        }
 }
 
+void ovl_path_lowerdata(struct dentry *dentry, struct path *path)
+{
+       struct ovl_entry *oe = dentry->d_fsdata;
+
+       if (oe->numlower) {
+               path->mnt = oe->lowerstack[oe->numlower - 1].layer->mnt;
+               path->dentry = oe->lowerstack[oe->numlower - 1].dentry;
+       } else {
+               *path = (struct path) { };
+       }
+}
+
 enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path)
 {
        enum ovl_path_type type = ovl_path_type(dentry);