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Subject[PATCH 10/28] ovl: Copy up meta inode data from lowest data inode
Date
From: Vivek Goyal <vgoyal@redhat.com>

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>
---
fs/overlayfs/copy_up.c | 13 +++++++++----
fs/overlayfs/overlayfs.h | 1 +
fs/overlayfs/util.c | 12 ++++++++++++
3 files changed, 22 insertions(+), 4 deletions(-)

diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c
index 7d01afd345e9..8c05e9ad9782 100644
--- 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 b1f6591b9af4..31795c041d61 100644
--- 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 ab9a8fae0f99..32ff67fa0bfb 100644
--- 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);
--
2.14.3
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