From 5f6bed76c0c85cb4d04885a5de00b629deee550b Mon Sep 17 00:00:00 2001 From: Dave Chinner Date: Thu, 27 Jun 2013 16:04:52 +1000 Subject: [PATCH] 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_buf_item.c | 75 +++++++++++++++++++++++++++--------------- fs/xfs/xfs_buf_item.h | 4 ++- fs/xfs/xfs_trace.h | 4 +++ fs/xfs/xfs_trans.h | 1 + fs/xfs/xfs_trans_buf.c | 34 +++++++++++++++++-- 5 files changed, 87 insertions(+), 31 deletions(-) diff --git a/fs/xfs/xfs_buf_item.c b/fs/xfs/xfs_buf_item.c index 4ec431777048..61f68768ee84 100644 --- a/fs/xfs/xfs_buf_item.c +++ b/fs/xfs/xfs_buf_item.c @@ -140,6 +140,16 @@ xfs_buf_item_size( ASSERT(bip->bli_flags & XFS_BLI_LOGGED); + if (bip->bli_flags & XFS_BLI_ORDERED) { + /* + * The buffer has been logged just to order it. + * It is not being included in the transaction + * commit, so no vectors are used at all. + */ + trace_xfs_buf_item_size_ordered(bip); + return XFS_LOG_VEC_ORDERED; + } + /* * the vector count is based on the number of buffer vectors we have * dirty bits in. This will only be greater than one when we have a @@ -212,6 +222,7 @@ xfs_buf_item_format_segment( goto out; } + /* * Fill in an iovec for each set of contiguous chunks. */ @@ -311,6 +322,16 @@ xfs_buf_item_format( bip->bli_flags &= ~XFS_BLI_INODE_BUF; } + if ((bip->bli_flags & (XFS_BLI_ORDERED|XFS_BLI_STALE)) == + XFS_BLI_ORDERED) { + /* + * The buffer has been logged just to order it. It is not being + * included in the transaction commit, so don't format it. + */ + trace_xfs_buf_item_format_ordered(bip); + return; + } + for (i = 0; i < bip->bli_format_count; i++) { vecp = xfs_buf_item_format_segment(bip, vecp, offset, &bip->bli_formats[i]); @@ -340,6 +361,7 @@ xfs_buf_item_pin( ASSERT(atomic_read(&bip->bli_refcount) > 0); ASSERT((bip->bli_flags & XFS_BLI_LOGGED) || + (bip->bli_flags & XFS_BLI_ORDERED) || (bip->bli_flags & XFS_BLI_STALE)); trace_xfs_buf_item_pin(bip); @@ -512,8 +534,9 @@ xfs_buf_item_unlock( { struct xfs_buf_log_item *bip = BUF_ITEM(lip); struct xfs_buf *bp = bip->bli_buf; - int aborted, clean, i; - uint hold; + bool clean; + bool aborted; + int flags; /* Clear the buffer's association with this transaction. */ bp->b_transp = NULL; @@ -524,23 +547,21 @@ xfs_buf_item_unlock( * (cancelled) buffers at unpin time, but we'll never go through the * pin/unpin cycle if we abort inside commit. */ - aborted = (lip->li_flags & XFS_LI_ABORTED) != 0; - + aborted = (lip->li_flags & XFS_LI_ABORTED) ? true : false; /* - * Before possibly freeing the buf item, determine if we should - * release the buffer at the end of this routine. + * Before possibly freeing the buf item, copy the per-transaction state + * so we can reference it safely later after clearing it from the + * buffer log item. */ - hold = bip->bli_flags & XFS_BLI_HOLD; - - /* Clear the per transaction state. */ - bip->bli_flags &= ~(XFS_BLI_LOGGED | XFS_BLI_HOLD); + flags = bip->bli_flags; + bip->bli_flags &= ~(XFS_BLI_LOGGED | XFS_BLI_HOLD | XFS_BLI_ORDERED); /* * If the buf item is marked stale, then don't do anything. We'll * unlock the buffer and free the buf item when the buffer is unpinned * for the last time. */ - if (bip->bli_flags & XFS_BLI_STALE) { + if (flags & XFS_BLI_STALE) { trace_xfs_buf_item_unlock_stale(bip); ASSERT(bip->__bli_format.blf_flags & XFS_BLF_CANCEL); if (!aborted) { @@ -557,13 +578,19 @@ xfs_buf_item_unlock( * be the only reference to the buf item, so we free it anyway * regardless of whether it is dirty or not. A dirty abort implies a * shutdown, anyway. + * + * Ordered buffers are dirty but may have no recorded changes, so ensure + * we only release clean items here. */ - clean = 1; - for (i = 0; i < bip->bli_format_count; i++) { - if (!xfs_bitmap_empty(bip->bli_formats[i].blf_data_map, - bip->bli_formats[i].blf_map_size)) { - clean = 0; - break; + clean = (flags & XFS_BLI_DIRTY) ? false : true; + if (clean) { + int i; + for (i = 0; i < bip->bli_format_count; i++) { + if (!xfs_bitmap_empty(bip->bli_formats[i].blf_data_map, + bip->bli_formats[i].blf_map_size)) { + clean = false; + break; + } } } if (clean) @@ -576,7 +603,7 @@ xfs_buf_item_unlock( } else atomic_dec(&bip->bli_refcount); - if (!hold) + if (!(flags & XFS_BLI_HOLD)) xfs_buf_relse(bp); } @@ -841,12 +868,6 @@ xfs_buf_item_log( uint end; struct xfs_buf *bp = bip->bli_buf; - /* - * Mark the item as having some dirty data for - * quick reference in xfs_buf_item_dirty. - */ - bip->bli_flags |= XFS_BLI_DIRTY; - /* * walk each buffer segment and mark them dirty appropriately. */ @@ -873,7 +894,7 @@ xfs_buf_item_log( /* - * Return 1 if the buffer has some data that has been logged (at any + * Return 1 if the buffer has been logged or ordered in a transaction (at any * point, not just the current transaction) and 0 if not. */ uint @@ -907,11 +928,11 @@ void xfs_buf_item_relse( xfs_buf_t *bp) { - xfs_buf_log_item_t *bip; + xfs_buf_log_item_t *bip = bp->b_fspriv; trace_xfs_buf_item_relse(bp, _RET_IP_); + ASSERT(!(bip->bli_item.li_flags & XFS_LI_IN_AIL)); - bip = bp->b_fspriv; bp->b_fspriv = bip->bli_item.li_bio_list; if (bp->b_fspriv == NULL) bp->b_iodone = NULL; diff --git a/fs/xfs/xfs_buf_item.h b/fs/xfs/xfs_buf_item.h index 2573d2a75fc8..0f1c247dc680 100644 --- a/fs/xfs/xfs_buf_item.h +++ b/fs/xfs/xfs_buf_item.h @@ -120,6 +120,7 @@ xfs_blft_from_flags(struct xfs_buf_log_format *blf) #define XFS_BLI_INODE_ALLOC_BUF 0x10 #define XFS_BLI_STALE_INODE 0x20 #define XFS_BLI_INODE_BUF 0x40 +#define XFS_BLI_ORDERED 0x80 #define XFS_BLI_FLAGS \ { XFS_BLI_HOLD, "HOLD" }, \ @@ -128,7 +129,8 @@ xfs_blft_from_flags(struct xfs_buf_log_format *blf) { XFS_BLI_LOGGED, "LOGGED" }, \ { XFS_BLI_INODE_ALLOC_BUF, "INODE_ALLOC" }, \ { XFS_BLI_STALE_INODE, "STALE_INODE" }, \ - { XFS_BLI_INODE_BUF, "INODE_BUF" } + { XFS_BLI_INODE_BUF, "INODE_BUF" }, \ + { XFS_BLI_ORDERED, "ORDERED" } #ifdef __KERNEL__ diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h index e31867270077..ee8b3a3b5d65 100644 --- a/fs/xfs/xfs_trace.h +++ b/fs/xfs/xfs_trace.h @@ -486,9 +486,12 @@ DEFINE_EVENT(xfs_buf_item_class, name, \ TP_PROTO(struct xfs_buf_log_item *bip), \ TP_ARGS(bip)) DEFINE_BUF_ITEM_EVENT(xfs_buf_item_size); +DEFINE_BUF_ITEM_EVENT(xfs_buf_item_size_ordered); DEFINE_BUF_ITEM_EVENT(xfs_buf_item_size_stale); DEFINE_BUF_ITEM_EVENT(xfs_buf_item_format); +DEFINE_BUF_ITEM_EVENT(xfs_buf_item_format_ordered); DEFINE_BUF_ITEM_EVENT(xfs_buf_item_format_stale); +DEFINE_BUF_ITEM_EVENT(xfs_buf_item_ordered); DEFINE_BUF_ITEM_EVENT(xfs_buf_item_pin); DEFINE_BUF_ITEM_EVENT(xfs_buf_item_unpin); DEFINE_BUF_ITEM_EVENT(xfs_buf_item_unpin_stale); @@ -508,6 +511,7 @@ DEFINE_BUF_ITEM_EVENT(xfs_trans_bjoin); DEFINE_BUF_ITEM_EVENT(xfs_trans_bhold); DEFINE_BUF_ITEM_EVENT(xfs_trans_bhold_release); DEFINE_BUF_ITEM_EVENT(xfs_trans_binval); +DEFINE_BUF_ITEM_EVENT(xfs_trans_buf_ordered); DECLARE_EVENT_CLASS(xfs_lock_class, TP_PROTO(struct xfs_inode *ip, unsigned lock_flags, 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); diff --git a/fs/xfs/xfs_trans_buf.c b/fs/xfs/xfs_trans_buf.c index 73a5fa457e16..aa5a04b844d6 100644 --- a/fs/xfs/xfs_trans_buf.c +++ b/fs/xfs/xfs_trans_buf.c @@ -397,7 +397,6 @@ shutdown_abort: return XFS_ERROR(EIO); } - /* * Release the buffer bp which was previously acquired with one of the * xfs_trans_... buffer allocation routines if the buffer has not @@ -603,8 +602,14 @@ xfs_trans_log_buf(xfs_trans_t *tp, tp->t_flags |= XFS_TRANS_DIRTY; bip->bli_item.li_desc->lid_flags |= XFS_LID_DIRTY; - bip->bli_flags |= XFS_BLI_LOGGED; - xfs_buf_item_log(bip, first, last); + + /* + * If we have an ordered buffer we are not logging any dirty range but + * it still needs to be marked dirty and that it has been logged. + */ + bip->bli_flags |= XFS_BLI_DIRTY | XFS_BLI_LOGGED; + if (!(bip->bli_flags & XFS_BLI_ORDERED)) + xfs_buf_item_log(bip, first, last); } @@ -756,6 +761,29 @@ xfs_trans_inode_alloc_buf( xfs_trans_buf_set_type(tp, bp, XFS_BLFT_DINO_BUF); } +/* + * Mark the buffer as ordered for this transaction. This means + * that the contents of the buffer are not recorded in the transaction + * but it is tracked in the AIL as though it was. This allows us + * to record logical changes in transactions rather than the physical + * changes we make to the buffer without changing writeback ordering + * constraints of metadata buffers. + */ +void +xfs_trans_ordered_buf( + struct xfs_trans *tp, + struct xfs_buf *bp) +{ + struct xfs_buf_log_item *bip = bp->b_fspriv; + + ASSERT(bp->b_transp == tp); + ASSERT(bip != NULL); + ASSERT(atomic_read(&bip->bli_refcount) > 0); + + bip->bli_flags |= XFS_BLI_ORDERED; + trace_xfs_buf_item_ordered(bip); +} + /* * Set the type of the buffer for log recovery so that it can correctly identify * and hence attach the correct buffer ops to the buffer after replay. -- 2.20.1