From: Brian Foster Date: Fri, 5 Oct 2018 02:36:11 +0000 (-0500) Subject: xfs: replace dop_low with transaction flag X-Git-Tag: v4.19.0-rc0~13 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=565e96c61088d336eecad603862437ed4c12d000;p=thirdparty%2Fxfsprogs-dev.git xfs: replace dop_low with transaction flag Source kernel commit: 1214f1cf663b0939fbb8f1bccdc74c1d1e452d53 The dop_low field enables the low free space allocation mode when a previous allocation has detected difficulty allocating blocks. It has historically been part of the xfs_defer_ops structure, which means if enabled, it remains enabled across a set of transactions until the deferred operations have completed and the dfops is reset. Now that the dfops is embedded in the transaction, we can save a bit more space by using a transaction flag rather than a standalone boolean. Drop the ->dop_low field and replace it with a transaction flag that is set at the same points, carried across rolling transactions and cleared on completion of deferred operations. This essentially emulates the behavior of ->dop_low and so should not change behavior. Signed-off-by: Brian Foster Reviewed-by: Darrick J. Wong Reviewed-by: Christoph Hellwig Signed-off-by: Darrick J. Wong Signed-off-by: Eric Sandeen --- diff --git a/include/xfs_trans.h b/include/xfs_trans.h index c11e694f8..c35f1f418 100644 --- a/include/xfs_trans.h +++ b/include/xfs_trans.h @@ -70,8 +70,6 @@ struct xfs_defer_ops { /* 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 { diff --git a/libxfs/xfs_bmap.c b/libxfs/xfs_bmap.c index f94dd2b92..ffcfd16b3 100644 --- a/libxfs/xfs_bmap.c +++ b/libxfs/xfs_bmap.c @@ -691,7 +691,7 @@ xfs_bmap_extents_to_btree( if (tp->t_firstblock == NULLFSBLOCK) { args.type = XFS_ALLOCTYPE_START_BNO; args.fsbno = XFS_INO_TO_FSB(mp, ip->i_ino); - } else if (tp->t_dfops->dop_low) { + } else if (tp->t_flags & XFS_TRANS_LOWMODE) { args.type = XFS_ALLOCTYPE_START_BNO; args.fsbno = tp->t_firstblock; } else { @@ -3440,7 +3440,7 @@ xfs_bmap_btalloc( error = xfs_bmap_btalloc_nullfb(ap, &args, &blen); if (error) return error; - } else if (ap->tp->t_dfops->dop_low) { + } else if (ap->tp->t_flags & XFS_TRANS_LOWMODE) { if (xfs_inode_is_filestream(ap->ip)) args.type = XFS_ALLOCTYPE_FIRST_AG; else @@ -3475,7 +3475,7 @@ xfs_bmap_btalloc( * is >= the stripe unit and the allocation offset is * at the end of file. */ - if (!ap->tp->t_dfops->dop_low && ap->aeof) { + if (!(ap->tp->t_flags & XFS_TRANS_LOWMODE) && ap->aeof) { if (!ap->offset) { args.alignment = stripe_align; atype = args.type; @@ -3567,7 +3567,7 @@ xfs_bmap_btalloc( args.total = ap->minlen; if ((error = xfs_alloc_vextent(&args))) return error; - ap->tp->t_dfops->dop_low = true; + ap->tp->t_flags |= XFS_TRANS_LOWMODE; } if (args.fsbno != NULLFSBLOCK) { /* diff --git a/libxfs/xfs_bmap_btree.c b/libxfs/xfs_bmap_btree.c index 4c513d0e3..91cc40f94 100644 --- a/libxfs/xfs_bmap_btree.c +++ b/libxfs/xfs_bmap_btree.c @@ -223,7 +223,7 @@ xfs_bmbt_alloc_block( * block allocation here and corrupt the filesystem. */ args.minleft = args.tp->t_blk_res; - } else if (cur->bc_tp->t_dfops->dop_low) { + } else if (cur->bc_tp->t_flags & XFS_TRANS_LOWMODE) { args.type = XFS_ALLOCTYPE_START_BNO; } else { args.type = XFS_ALLOCTYPE_NEAR_BNO; @@ -250,7 +250,7 @@ xfs_bmbt_alloc_block( error = xfs_alloc_vextent(&args); if (error) goto error0; - cur->bc_tp->t_dfops->dop_low = true; + cur->bc_tp->t_flags |= XFS_TRANS_LOWMODE; } if (WARN_ON_ONCE(args.fsbno == NULLFSBLOCK)) { *stat = 0; diff --git a/libxfs/xfs_defer.c b/libxfs/xfs_defer.c index 5342d683e..b7e4319c1 100644 --- a/libxfs/xfs_defer.c +++ b/libxfs/xfs_defer.c @@ -330,9 +330,14 @@ xfs_defer_reset( ASSERT(!xfs_defer_has_unfinished_work(dop)); - dop->dop_low = false; memset(dop->dop_inodes, 0, sizeof(dop->dop_inodes)); memset(dop->dop_bufs, 0, sizeof(dop->dop_bufs)); + + /* + * Low mode state transfers across transaction rolls to mirror dfops + * lifetime. Clear it now that dfops is reset. + */ + tp->t_flags &= ~XFS_TRANS_LOWMODE; } /* @@ -590,7 +595,14 @@ xfs_defer_move( 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; + + /* + * Low free space mode was historically controlled by a dfops field. + * This meant that low mode state potentially carried across multiple + * transaction rolls. Transfer low mode on a dfops move to preserve + * that behavior. + */ + dtp->t_flags |= (stp->t_flags & XFS_TRANS_LOWMODE); xfs_defer_reset(stp); } diff --git a/libxfs/xfs_defer.h b/libxfs/xfs_defer.h index d60c50498..8908a2716 100644 --- a/libxfs/xfs_defer.h +++ b/libxfs/xfs_defer.h @@ -25,17 +25,6 @@ struct xfs_defer_pending { /* * Header for deferred operation list. - * - * dop_low is used by the allocator to activate the lowspace algorithm - - * when free space is running low the extent allocator may choose to - * allocate an extent from an AG without leaving sufficient space for - * a btree split when inserting the new extent. In this case the allocator - * will enable the lowspace algorithm which is supposed to allow further - * allocations (such as btree splits and newroots) to allocate from - * sequential AGs. In order to avoid locking AGs out of order the lowspace - * algorithm will start searching for free space from AG 0. If the correct - * transaction reservations have been made then this algorithm will eventually - * find all the space it needs. */ enum xfs_defer_ops_type { XFS_DEFER_OPS_TYPE_BMAP, diff --git a/libxfs/xfs_shared.h b/libxfs/xfs_shared.h index 22089f1c8..1c5debe74 100644 --- a/libxfs/xfs_shared.h +++ b/libxfs/xfs_shared.h @@ -64,6 +64,18 @@ void xfs_log_get_max_trans_res(struct xfs_mount *mp, #define XFS_TRANS_RESERVE 0x20 /* OK to use reserved data blocks */ #define XFS_TRANS_NO_WRITECOUNT 0x40 /* do not elevate SB writecount */ #define XFS_TRANS_NOFS 0x80 /* pass KM_NOFS to kmem_alloc */ +/* + * LOWMODE is used by the allocator to activate the lowspace algorithm - when + * free space is running low the extent allocator may choose to allocate an + * extent from an AG without leaving sufficient space for a btree split when + * inserting the new extent. In this case the allocator will enable the + * lowspace algorithm which is supposed to allow further allocations (such as + * btree splits and newroots) to allocate from sequential AGs. In order to + * avoid locking AGs out of order the lowspace algorithm will start searching + * for free space from AG 0. If the correct transaction reservations have been + * made then this algorithm will eventually find all the space it needs. + */ +#define XFS_TRANS_LOWMODE 0x100 /* allocate in low space mode */ /* * Field values for xfs_trans_mod_sb.