On Fri 25-01-19 20:30:54, zhangyi (F) wrote: > We do not unmap and clear dirty flag when forgetting a buffer without > journal or does not belongs to any transaction, so the invalid dirty > data may still be written to the disk later. It's fine if the > corresponding block is never used before the next mount, and it's also > fine that we invoke clean_bdev_aliases() related functions to unmap > the block device mapping when re-allocating such freed block as data > block. But this logic is somewhat fragile and risky that may lead to > data corruption if we forget to clean bdev aliases. So, It's better to > discard dirty data during forget time. > > We have been already handled all the cases of forgetting journalled > buffer, this patch deal with the remaining two cases. > > - buffer is not journalled yet, > - buffer is journalled but doesn't belongs to any transaction. > > We invoke __bforget() instead of __brelese() when forgetting an > un-journalled buffer in jbd2_journal_forget(). After this patch we can > remove all clean_bdev_aliases() related calls in ext4. > > Suggested-by: Jan Kara <jack@xxxxxxx> > Signed-off-by: zhangyi (F) <yi.zhang@xxxxxxxxxx> Thanks for the patch! Just one small comment below: > + /* > + * The buffer is still not written to disk, we should > + * attach this buffer to current transaction to prevent > + * missing writing back when doing checkpoint before > + * the current transaction complete submittion. > + */ > + __jbd2_journal_temp_unlink_buffer(jh); Calling __jbd2_journal_temp_unlink_buffer() is not needed when you know the buffer does not belong to any transaction. Otherwise the patch looks good to me so feel free to add: Reviewed-by: Jan Kara <jack@xxxxxxx> after fixing this. Honza > + clear_buffer_dirty(bh); > + __jbd2_journal_file_buffer(jh, transaction, BJ_Forget); > + spin_unlock(&journal->j_list_lock); > } > > -not_jbd: > jbd_unlock_bh_state(bh); > __brelse(bh); > drop: > @@ -1643,6 +1673,11 @@ int jbd2_journal_forget (handle_t *handle, struct buffer_head *bh) > handle->h_buffer_credits++; > } > return err; > + > +not_jbd: > + jbd_unlock_bh_state(bh); > + __bforget(bh); > + goto drop; > } > > /** > -- > 2.7.4 > -- Jan Kara <jack@xxxxxxxx> SUSE Labs, CR
