ecryptfs: fix unlink and rmdir in face of underlying fs modifications

[sfrench/cifs-2.6.git] / fs / ecryptfs / inode.c

diff --git a/fs/ecryptfs/inode.c b/fs/ecryptfs/inode.c
index 18426f4855f11b3e561f1cc35ee381fac3f2cfcc..a905d5f4f3b0726303595e39ba40309d68baa422 100644 (file)
--- a/fs/ecryptfs/inode.c
+++ b/fs/ecryptfs/inode.c
@@ -128,13 +128,20 @@ static int ecryptfs_do_unlink(struct inode *dir, struct dentry *dentry,
                              struct inode *inode)
 {
        struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
-       struct inode *lower_dir_inode = ecryptfs_inode_to_lower(dir);
        struct dentry *lower_dir_dentry;
+       struct inode *lower_dir_inode;
        int rc;
 
-       dget(lower_dentry);
-       lower_dir_dentry = lock_parent(lower_dentry);
-       rc = vfs_unlink(lower_dir_inode, lower_dentry, NULL);
+       lower_dir_dentry = ecryptfs_dentry_to_lower(dentry->d_parent);
+       lower_dir_inode = d_inode(lower_dir_dentry);
+       inode_lock_nested(lower_dir_inode, I_MUTEX_PARENT);
+       dget(lower_dentry);     // don't even try to make the lower negative
+       if (lower_dentry->d_parent != lower_dir_dentry)
+               rc = -EINVAL;
+       else if (d_unhashed(lower_dentry))
+               rc = -EINVAL;
+       else
+               rc = vfs_unlink(lower_dir_inode, lower_dentry, NULL);
        if (rc) {
                printk(KERN_ERR "Error in vfs_unlink; rc = [%d]\n", rc);
                goto out_unlock;
@@ -142,10 +149,11 @@ static int ecryptfs_do_unlink(struct inode *dir, struct dentry *dentry,
        fsstack_copy_attr_times(dir, lower_dir_inode);
        set_nlink(inode, ecryptfs_inode_to_lower(inode)->i_nlink);
        inode->i_ctime = dir->i_ctime;
-       d_drop(dentry);
 out_unlock:
-       unlock_dir(lower_dir_dentry);
        dput(lower_dentry);
+       inode_unlock(lower_dir_inode);
+       if (!rc)
+               d_drop(dentry);
        return rc;
 }
 
@@ -512,22 +520,30 @@ static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry)
 {
        struct dentry *lower_dentry;
        struct dentry *lower_dir_dentry;
+       struct inode *lower_dir_inode;
        int rc;
 
        lower_dentry = ecryptfs_dentry_to_lower(dentry);
-       dget(dentry);
-       lower_dir_dentry = lock_parent(lower_dentry);
-       dget(lower_dentry);
-       rc = vfs_rmdir(d_inode(lower_dir_dentry), lower_dentry);
-       dput(lower_dentry);
-       if (!rc && d_really_is_positive(dentry))
+       lower_dir_dentry = ecryptfs_dentry_to_lower(dentry->d_parent);
+       lower_dir_inode = d_inode(lower_dir_dentry);
+
+       inode_lock_nested(lower_dir_inode, I_MUTEX_PARENT);
+       dget(lower_dentry);     // don't even try to make the lower negative
+       if (lower_dentry->d_parent != lower_dir_dentry)
+               rc = -EINVAL;
+       else if (d_unhashed(lower_dentry))
+               rc = -EINVAL;
+       else
+               rc = vfs_rmdir(lower_dir_inode, lower_dentry);
+       if (!rc) {
                clear_nlink(d_inode(dentry));
-       fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
-       set_nlink(dir, d_inode(lower_dir_dentry)->i_nlink);
-       unlock_dir(lower_dir_dentry);
+               fsstack_copy_attr_times(dir, lower_dir_inode);
+               set_nlink(dir, lower_dir_inode->i_nlink);
+       }
+       dput(lower_dentry);
+       inode_unlock(lower_dir_inode);
        if (!rc)
                d_drop(dentry);
-       dput(dentry);
        return rc;
 }
 
@@ -565,20 +581,22 @@ ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry,
        struct dentry *lower_new_dentry;
        struct dentry *lower_old_dir_dentry;
        struct dentry *lower_new_dir_dentry;
-       struct dentry *trap = NULL;
+       struct dentry *trap;
        struct inode *target_inode;
 
        if (flags)
                return -EINVAL;
 
+       lower_old_dir_dentry = ecryptfs_dentry_to_lower(old_dentry->d_parent);
+       lower_new_dir_dentry = ecryptfs_dentry_to_lower(new_dentry->d_parent);
+
        lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
        lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
-       dget(lower_old_dentry);
-       dget(lower_new_dentry);
-       lower_old_dir_dentry = dget_parent(lower_old_dentry);
-       lower_new_dir_dentry = dget_parent(lower_new_dentry);
+
        target_inode = d_inode(new_dentry);
+
        trap = lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
+       dget(lower_new_dentry);
        rc = -EINVAL;
        if (lower_old_dentry->d_parent != lower_old_dir_dentry)
                goto out_lock;
@@ -606,11 +624,8 @@ ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry,
        if (new_dir != old_dir)
                fsstack_copy_attr_all(old_dir, d_inode(lower_old_dir_dentry));
 out_lock:
-       unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
-       dput(lower_new_dir_dentry);
-       dput(lower_old_dir_dentry);
        dput(lower_new_dentry);
-       dput(lower_old_dentry);
+       unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
        return rc;
 }