ovl: rename: simplify handling of lower/merged directory

d_is_dir() is safe to call on a negative dentry.  Use this fact to simplify
handling of the lower or merged directories.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

2 files changed, 12 insertions, 21 deletions

diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c
index 76b1edccbedd..69c3971a9992 100644
--- a/fs/overlayfs/dir.c
+++ b/fs/overlayfs/dir.c
@@ -761,13 +761,18 @@ static int ovl_rmdir(struct inode *dir, struct dentry *dentry)
         return ovl_do_remove(dentry, true);
 }
 
+static bool ovl_type_merge_or_lower(struct dentry *dentry)
+{
+        enum ovl_path_type type = ovl_path_type(dentry);
+
+        return OVL_TYPE_MERGE(type) || !OVL_TYPE_UPPER(type);
+}
+
 static int ovl_rename(struct inode *olddir, struct dentry *old,
                       struct inode *newdir, struct dentry *new,
                       unsigned int flags)
 {
         int err;
-        enum ovl_path_type old_type;
-        enum ovl_path_type new_type;
         struct dentry *old_upperdir;
         struct dentry *new_upperdir;
         struct dentry *olddentry;
@@ -778,7 +783,7 @@ static int ovl_rename(struct inode *olddir, struct dentry *old,
         bool cleanup_whiteout = false;
         bool overwrite = !(flags & RENAME_EXCHANGE);
         bool is_dir = d_is_dir(old);
-        bool new_is_dir = false;
+        bool new_is_dir = d_is_dir(new);
         struct dentry *opaquedir = NULL;
         const struct cred *old_cred = NULL;
 
@@ -789,22 +794,11 @@ static int ovl_rename(struct inode *olddir, struct dentry *old,
         flags &= ~RENAME_NOREPLACE;
 
         /* Don't copy up directory trees */
-        old_type = ovl_path_type(old);
         err = -EXDEV;
-        if (OVL_TYPE_MERGE_OR_LOWER(old_type) && is_dir)
+        if (is_dir && ovl_type_merge_or_lower(old))
+                goto out;
+        if (!overwrite && new_is_dir && ovl_type_merge_or_lower(new))
                 goto out;
-
-        if (new->d_inode) {
-                if (d_is_dir(new))
-                        new_is_dir = true;
-
-                new_type = ovl_path_type(new);
-                err = -EXDEV;
-                if (!overwrite && OVL_TYPE_MERGE_OR_LOWER(new_type) && new_is_dir)
-                        goto out;
-        } else {
-                new_type = __OVL_PATH_UPPER;
-        }
 
         err = ovl_want_write(old);
         if (err)
@@ -828,7 +822,7 @@ static int ovl_rename(struct inode *olddir, struct dentry *old,
 
         old_cred = ovl_override_creds(old->d_sb);
 
-        if (overwrite && OVL_TYPE_MERGE_OR_LOWER(new_type) && new_is_dir) {
+        if (overwrite && new_is_dir && ovl_type_merge_or_lower(new)) {
                 opaquedir = ovl_check_empty_and_clear(new);
                 err = PTR_ERR(opaquedir);
                 if (IS_ERR(opaquedir)) {
diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
index f183d1db78bd..db28512165c5 100644
--- a/fs/overlayfs/overlayfs.h
+++ b/fs/overlayfs/overlayfs.h
@@ -18,9 +18,6 @@ enum ovl_path_type {
 
 #define OVL_TYPE_UPPER(type)    ((type) & __OVL_PATH_UPPER)
 #define OVL_TYPE_MERGE(type)    ((type) & __OVL_PATH_MERGE)
-#define OVL_TYPE_MERGE_OR_LOWER(type) \
-        (OVL_TYPE_MERGE(type) || !OVL_TYPE_UPPER(type))
-
 
 #define OVL_XATTR_PREFIX XATTR_TRUSTED_PREFIX "overlay."
 #define OVL_XATTR_OPAQUE OVL_XATTR_PREFIX "opaque"