Wrapfs: ->setattr fixes

Call inode_change_ok on our inode, not lower.
Don't copy inode sizes (VFS does it).
Pass lower file in struct iattr passed to notify_change on lower inode.

Signed-off-by: Erez Zadok <ezk@cs.sunysb.edu>

diff --git a/fs/wrapfs/inode.c b/fs/wrapfs/inode.c
index 9fc3c66d751693a380c2cb81c7a21cc8af13101f..cea3e36912ed182dbd8e1e62bb7045c0336ea484 100644 (file)
--- a/fs/wrapfs/inode.c
+++ b/fs/wrapfs/inode.c
@@ -427,24 +427,27 @@ static int wrapfs_setattr(struct dentry *dentry, struct iattr *ia)
        struct inode *inode;
        struct inode *lower_inode;
        struct path lower_path;
+       struct iattr lower_ia;
 
        inode = dentry->d_inode;
 
        /*
-        * mode change is for clearing setuid/setgid. Allow lower file system
-        * to reinterpret it in its own way.
+        * Check if user has permission to change inode.  We don't check if
+        * this user can change the lower inode: that should happen when
+        * calling notify_change on the lower inode.
         */
-       if (ia->ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID))
-               ia->ia_valid &= ~ATTR_MODE;
+       err = inode_change_ok(inode, ia);
+       if (err)
+               goto out_err;
 
        wrapfs_get_lower_path(dentry, &lower_path);
        lower_dentry = lower_path.dentry;
        lower_inode = wrapfs_lower_inode(inode);
 
-       /* check if user has permission to change lower inode */
-       err = inode_change_ok(lower_inode, ia);
-       if (err)
-               goto out;
+       /* prepare our own lower struct iattr (with the lower file) */
+       memcpy(&lower_ia, ia, sizeof(lower_ia));
+       if (ia->ia_valid & ATTR_FILE)
+               lower_ia.ia_file = wrapfs_lower_file(ia->ia_file);
 
        /*
         * If shrinking, first truncate upper level to cancel writing dirty
@@ -461,6 +464,13 @@ static int wrapfs_setattr(struct dentry *dentry, struct iattr *ia)
                truncate_setsize(inode, ia->ia_size);
        }
 
+       /*
+        * mode change is for clearing setuid/setgid bits. Allow lower fs
+        * to interpret this in its own way.
+        */
+       if (lower_ia.ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID))
+               lower_ia.ia_valid &= ~ATTR_MODE;
+
        /* notify the (possibly copied-up) lower inode */
        /*
         * Note: we use lower_dentry->d_inode, because lower_inode may be
@@ -468,24 +478,22 @@ static int wrapfs_setattr(struct dentry *dentry, struct iattr *ia)
         * tries to open(), unlink(), then ftruncate() a file.
         */
        mutex_lock(&lower_dentry->d_inode->i_mutex);
-       err = notify_change(lower_dentry, ia);
+       err = notify_change(lower_dentry, &lower_ia); /* note: lower_ia */
        mutex_unlock(&lower_dentry->d_inode->i_mutex);
        if (err)
                goto out;
 
        /* get attributes from the lower inode */
        fsstack_copy_attr_all(inode, lower_inode);
-
-       if (ia->ia_valid & ATTR_MTIME_SET)
-               inode->i_mtime = lower_inode->i_mtime;
-       if (ia->ia_valid & ATTR_CTIME)
-               inode->i_ctime = lower_inode->i_ctime;
-       if (ia->ia_valid & ATTR_ATIME_SET)
-               inode->i_atime = lower_inode->i_atime;
-       fsstack_copy_inode_size(inode, lower_inode);
+       /*
+        * Not running fsstack_copy_inode_size(inode, lower_inode), because
+        * VFS should update our inode size, and notify_change on
+        * lower_inode should update its size.
+        */
 
 out:
        wrapfs_put_lower_path(dentry, &lower_path);
+out_err:
        return err;
 }