From 5f6bed76c0c85cb4d04885a5de00b629deee550b Mon Sep 17 00:00:00 2001 From: Dave Chinner Date: Thu, 27 Jun 2013 16:04:52 +1000 Subject: xfs: Introduce an ordered buffer item If we have a buffer that we have modified but we do not wish to physically log in a transaction (e.g. we've logged a logical change), we still need to ensure that transactional integrity is maintained. Hence we must not move the tail of the log past the transaction that the buffer is associated with before the buffer is written to disk. This means these special buffers still need to be included in the transaction and added to the AIL just like a normal buffer, but we do not want the modifications to the buffer written into the transaction. IOWs, what we want is an "ordered buffer" that maintains the same transactional life cycle as a physically logged buffer, just without the transcribing of the modifications to the log. Hence we need to flag the buffer as an "ordered buffer" to avoid including it in vector size calculations or formatting during the transaction. Once the transaction is committed, the buffer appears for all intents to be the same as a physically logged buffer as it transitions through the log and AIL. Relogging will also work just fine for such an ordered buffer - the logical transaction will be replayed before the subsequent modifications that relog the buffer, so everything will be reconstructed correctly by recovery. Signed-off-by: Dave Chinner Reviewed-by: Mark Tinguely Signed-off-by: Ben Myers --- fs/xfs/xfs_trans.h | 1 + 1 file changed, 1 insertion(+) (limited to 'fs/xfs/xfs_trans.h') diff --git a/fs/xfs/xfs_trans.h b/fs/xfs/xfs_trans.h index 6d526569820c..822570ec605a 100644 --- a/fs/xfs/xfs_trans.h +++ b/fs/xfs/xfs_trans.h @@ -498,6 +498,7 @@ void xfs_trans_bhold_release(xfs_trans_t *, struct xfs_buf *); void xfs_trans_binval(xfs_trans_t *, struct xfs_buf *); void xfs_trans_inode_buf(xfs_trans_t *, struct xfs_buf *); void xfs_trans_stale_inode_buf(xfs_trans_t *, struct xfs_buf *); +void xfs_trans_ordered_buf(xfs_trans_t *, struct xfs_buf *); void xfs_trans_dquot_buf(xfs_trans_t *, struct xfs_buf *, uint); void xfs_trans_inode_alloc_buf(xfs_trans_t *, struct xfs_buf *); void xfs_trans_ichgtime(struct xfs_trans *, struct xfs_inode *, int); -- cgit v1.2.3