From f5f4497f6e94707acf084f24c5425704dbee78a3 Mon Sep 17 00:00:00 2001 From: Brian Foster Date: Thu, 4 Oct 2018 21:36:10 -0500 Subject: [PATCH] xfs: support embedded dfops in transaction Source kernel commit: e021a2e5fc520d930f949f303e7307038e258645 The dfops structure used by multi-transaction operations is typically stored on the stack and carried around by the associated transaction. The lifecycle of dfops does not quite match that of the transaction, but they are tightly related in that the former depends on the latter. The relationship of these objects is tight enough that we can avoid the cumbersome boilerplate code required in most cases to manage them separately by just embedding an xfs_defer_ops in the transaction itself. This means that a transaction allocation returns with an initialized dfops, a transaction commit finishes pending deferred items before the tx commit, a transaction cancel cancels the dfops before the transaction and a transaction dup operation transfers the current dfops state to the new transaction. The dup operation is slightly complicated by the fact that we can no longer just copy a dfops pointer from the old transaction to the new transaction. This is solved through a dfops move helper that transfers the pending items and other dfops state across the transactions. This also requires that transaction rolling code always refer to the transaction for the current dfops reference. Finally, to facilitate incremental conversion to the internal dfops and continue to support the current external dfops mode of operation, create the new ->t_dfops_internal field with a layer of indirection. On allocation, ->t_dfops points to the internal dfops. This state is overridden by callers who re-init a local dfops on the transaction. Once ->t_dfops is overridden, the external dfops reference is maintained as the transaction rolls. This patch adds the fundamental ability to support an internal dfops. All codepaths that perform deferred processing continue to override the internal dfops until they are converted over in subsequent patches. Signed-off-by: Brian Foster Reviewed-by: Bill O'Donnell Reviewed-by: Christoph Hellwig Reviewed-by: Darrick J. Wong Signed-off-by: Darrick J. Wong Signed-off-by: Eric Sandeen --- include/xfs_trans.h | 15 +++++++++++++++ libxfs/trans.c | 29 ++++++++++++++++++++++++++--- libxfs/xfs_defer.c | 22 ++++++++++++++++++++++ libxfs/xfs_defer.h | 16 ++-------------- 4 files changed, 65 insertions(+), 17 deletions(-) diff --git a/include/xfs_trans.h b/include/xfs_trans.h index 1ad4e958d..4c722b59e 100644 --- a/include/xfs_trans.h +++ b/include/xfs_trans.h @@ -60,6 +60,20 @@ typedef struct xfs_qoff_logitem { xfs_qoff_logformat_t qql_format; /* logged structure */ } xfs_qoff_logitem_t; +#define XFS_DEFER_OPS_NR_INODES 2 /* join up to two inodes */ +#define XFS_DEFER_OPS_NR_BUFS 2 /* join up to two buffers */ + +struct xfs_defer_ops { + struct list_head dop_intake; /* unlogged pending work */ + struct list_head dop_pending; /* logged pending work */ + + /* relog these with each roll */ + struct xfs_inode *dop_inodes[XFS_DEFER_OPS_NR_INODES]; + struct xfs_buf *dop_bufs[XFS_DEFER_OPS_NR_BUFS]; + + bool dop_low; /* alloc in low mode */ +}; + typedef struct xfs_trans { unsigned int t_type; /* transaction type */ unsigned int t_log_res; /* amt of log space resvd */ @@ -75,6 +89,7 @@ typedef struct xfs_trans { long t_frextents_delta; /* superblock freextents chg */ struct list_head t_items; /* first log item desc chunk */ struct xfs_defer_ops *t_dfops; /* deferred operations */ + struct xfs_defer_ops t_dfops_internal; } xfs_trans_t; diff --git a/libxfs/trans.c b/libxfs/trans.c index bee4a761c..ec509667c 100644 --- a/libxfs/trans.c +++ b/libxfs/trans.c @@ -17,6 +17,7 @@ #include "xfs_inode.h" #include "xfs_trans.h" #include "xfs_sb.h" +#include "xfs_defer.h" static void xfs_trans_free_items(struct xfs_trans *tp); STATIC struct xfs_trans *xfs_trans_dup(struct xfs_trans *tp); @@ -159,7 +160,12 @@ xfs_trans_dup( ntp->t_blk_res = tp->t_blk_res - tp->t_blk_res_used; tp->t_blk_res = tp->t_blk_res_used; - ntp->t_dfops = tp->t_dfops; + /* copy the dfops pointer if it's external, otherwise move it */ + xfs_defer_init(ntp, &ntp->t_dfops_internal); + if (tp->t_dfops != &tp->t_dfops_internal) + ntp->t_dfops = tp->t_dfops; + else + xfs_defer_move(ntp->t_dfops, tp->t_dfops); return ntp; } @@ -260,6 +266,14 @@ libxfs_trans_alloc( INIT_LIST_HEAD(&tp->t_items); tp->t_firstblock = NULLFSBLOCK; + /* + * We only roll transactions with permanent log reservation. Don't init + * ->t_dfops to skip attempts to finish or cancel an empty dfops with a + * non-permanent res. + */ + if (resp->tr_logflags & XFS_TRANS_PERM_LOG_RES) + xfs_defer_init(tp, &tp->t_dfops_internal); + error = xfs_trans_reserve(tp, resp, blocks, rtextents); if (error) { xfs_trans_cancel(tp); @@ -319,6 +333,9 @@ libxfs_trans_cancel( if (tp == NULL) goto out; + if (tp->t_dfops) + xfs_defer_cancel(tp->t_dfops); + xfs_trans_free_items(tp); xfs_trans_free(tp); @@ -977,8 +994,14 @@ __xfs_trans_commit( if (tp == NULL) return 0; - ASSERT(!tp->t_dfops || - !xfs_defer_has_unfinished_work(tp->t_dfops) || regrant); + /* finish deferred items on final commit */ + if (!regrant && tp->t_dfops) { + error = xfs_defer_finish(&tp, tp->t_dfops); + if (error) { + xfs_defer_cancel(tp->t_dfops); + goto out_unreserve; + } + } if (!(tp->t_flags & XFS_TRANS_DIRTY)) { #ifdef XACT_DEBUG diff --git a/libxfs/xfs_defer.c b/libxfs/xfs_defer.c index 17ee0e0af..d8b940efb 100644 --- a/libxfs/xfs_defer.c +++ b/libxfs/xfs_defer.c @@ -555,3 +555,25 @@ xfs_defer_init( } trace_xfs_defer_init(mp, dop, _RET_IP_); } + +/* + * Move state from one xfs_defer_ops to another and reset the source to initial + * state. This is primarily used to carry state forward across transaction rolls + * with internal dfops. + */ +void +xfs_defer_move( + struct xfs_defer_ops *dst, + struct xfs_defer_ops *src) +{ + ASSERT(dst != src); + + list_splice_init(&src->dop_intake, &dst->dop_intake); + list_splice_init(&src->dop_pending, &dst->dop_pending); + + memcpy(dst->dop_inodes, src->dop_inodes, sizeof(dst->dop_inodes)); + memcpy(dst->dop_bufs, src->dop_bufs, sizeof(dst->dop_bufs)); + dst->dop_low = src->dop_low; + + xfs_defer_reset(src); +} diff --git a/libxfs/xfs_defer.h b/libxfs/xfs_defer.h index 8f58f217f..35507ca9a 100644 --- a/libxfs/xfs_defer.h +++ b/libxfs/xfs_defer.h @@ -7,6 +7,7 @@ #define __XFS_DEFER_H__ struct xfs_defer_op_type; +struct xfs_defer_ops; /* * Save a log intent item and a list of extents, so that we can replay @@ -45,20 +46,6 @@ enum xfs_defer_ops_type { XFS_DEFER_OPS_TYPE_MAX, }; -#define XFS_DEFER_OPS_NR_INODES 2 /* join up to two inodes */ -#define XFS_DEFER_OPS_NR_BUFS 2 /* join up to two buffers */ - -struct xfs_defer_ops { - struct list_head dop_intake; /* unlogged pending work */ - struct list_head dop_pending; /* logged pending work */ - - /* relog these with each roll */ - struct xfs_inode *dop_inodes[XFS_DEFER_OPS_NR_INODES]; - struct xfs_buf *dop_bufs[XFS_DEFER_OPS_NR_BUFS]; - - bool dop_low; /* alloc in low mode */ -}; - void xfs_defer_add(struct xfs_defer_ops *dop, enum xfs_defer_ops_type type, struct list_head *h); int xfs_defer_finish(struct xfs_trans **tp, struct xfs_defer_ops *dop); @@ -67,6 +54,7 @@ void xfs_defer_init(struct xfs_trans *tp, struct xfs_defer_ops *dop); bool xfs_defer_has_unfinished_work(struct xfs_defer_ops *dop); int xfs_defer_ijoin(struct xfs_defer_ops *dop, struct xfs_inode *ip); int xfs_defer_bjoin(struct xfs_defer_ops *dop, struct xfs_buf *bp); +void xfs_defer_move(struct xfs_defer_ops *dst, struct xfs_defer_ops *src); /* Description of a deferred type. */ struct xfs_defer_op_type { -- 2.47.2