ovl: decode lower file handles of unlinked but open files
Lookup overlay inode in cache by origin inode, so we can decode a file
handle of an open file even if the index has a whiteout index entry to
mark this overlay inode was unlinked.
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
diff --git a/fs/overlayfs/export.c b/fs/overlayfs/export.c
index f475a10..0bca38c 100644
--- a/fs/overlayfs/export.c
+++ b/fs/overlayfs/export.c
@@ -443,14 +443,22 @@ static struct dentry *ovl_lower_fh_to_d(struct super_block *sb,
struct ovl_path *stack = &origin;
struct dentry *dentry = NULL;
struct dentry *index = NULL;
+ struct inode *inode = NULL;
+ bool is_deleted = false;
int err;
/* First lookup indexed upper by fh */
if (ofs->indexdir) {
index = ovl_get_index_fh(ofs, fh);
err = PTR_ERR(index);
- if (IS_ERR(index))
- return ERR_PTR(err);
+ if (IS_ERR(index)) {
+ if (err != -ESTALE)
+ return ERR_PTR(err);
+
+ /* Found a whiteout index - treat as deleted inode */
+ is_deleted = true;
+ index = NULL;
+ }
}
/* Then lookup origin by fh */
@@ -461,6 +469,16 @@ static struct dentry *ovl_lower_fh_to_d(struct super_block *sb,
err = ovl_verify_origin(index, origin.dentry, false);
if (err)
goto out_err;
+ } else if (is_deleted) {
+ /* Lookup deleted non-dir by origin inode */
+ if (!d_is_dir(origin.dentry))
+ inode = ovl_lookup_inode(sb, origin.dentry);
+ err = -ESTALE;
+ if (!inode || atomic_read(&inode->i_count) == 1)
+ goto out_err;
+
+ /* Deleted but still open? */
+ index = dget(ovl_i_dentry_upper(inode));
}
dentry = ovl_get_dentry(sb, NULL, &origin, index);
@@ -468,6 +486,7 @@ static struct dentry *ovl_lower_fh_to_d(struct super_block *sb,
out:
dput(origin.dentry);
dput(index);
+ iput(inode);
return dentry;
out_err:
diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
index bfd7c76..56ba015 100644
--- a/fs/overlayfs/inode.c
+++ b/fs/overlayfs/inode.c
@@ -645,6 +645,22 @@ static bool ovl_verify_inode(struct inode *inode, struct dentry *lowerdentry,
return true;
}
+struct inode *ovl_lookup_inode(struct super_block *sb, struct dentry *origin)
+{
+ struct inode *inode, *key = d_inode(origin);
+
+ inode = ilookup5(sb, (unsigned long) key, ovl_inode_test, key);
+ if (!inode)
+ return NULL;
+
+ if (!ovl_verify_inode(inode, origin, NULL)) {
+ iput(inode);
+ return ERR_PTR(-ESTALE);
+ }
+
+ return inode;
+}
+
struct inode *ovl_get_inode(struct super_block *sb, struct dentry *upperdentry,
struct dentry *lowerdentry, struct dentry *index,
unsigned int numlower)
diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
index 40ba11e4..a47f914 100644
--- a/fs/overlayfs/overlayfs.h
+++ b/fs/overlayfs/overlayfs.h
@@ -322,6 +322,7 @@ int ovl_update_time(struct inode *inode, struct timespec *ts, int flags);
bool ovl_is_private_xattr(const char *name);
struct inode *ovl_new_inode(struct super_block *sb, umode_t mode, dev_t rdev);
+struct inode *ovl_lookup_inode(struct super_block *sb, struct dentry *origin);
struct inode *ovl_get_inode(struct super_block *sb, struct dentry *upperdentry,
struct dentry *lowerdentry, struct dentry *index,
unsigned int numlower);