From 46141dc891f7d28cc5cac473ad1a54a312c021c1 Mon Sep 17 00:00:00 2001 From: Gao Xiang Date: Tue, 23 Mar 2021 19:05:38 -0700 Subject: [PATCH] xfs: introduce xfs_ag_shrink_space() This patch introduces a helper to shrink unused space in the last AG by fixing up the freespace btree. Also make sure that the per-AG reservation works under the new AG size. If such per-AG reservation or extent allocation fails, roll the transaction so the new transaction could cancel without any side effects. Reviewed-by: Darrick J. Wong Signed-off-by: Gao Xiang Signed-off-by: Darrick J. Wong --- fs/xfs/libxfs/xfs_ag.c | 115 +++++++++++++++++++++++++++++++++++++++++ fs/xfs/libxfs/xfs_ag.h | 2 + 2 files changed, 117 insertions(+) diff --git a/fs/xfs/libxfs/xfs_ag.c b/fs/xfs/libxfs/xfs_ag.c index 9331f3516afa..c68a36688474 100644 --- a/fs/xfs/libxfs/xfs_ag.c +++ b/fs/xfs/libxfs/xfs_ag.c @@ -22,6 +22,11 @@ #include "xfs_ag.h" #include "xfs_ag_resv.h" #include "xfs_health.h" +#include "xfs_error.h" +#include "xfs_bmap.h" +#include "xfs_defer.h" +#include "xfs_log_format.h" +#include "xfs_trans.h" static int xfs_get_aghdr_buf( @@ -485,6 +490,116 @@ xfs_ag_init_headers( return error; } +int +xfs_ag_shrink_space( + struct xfs_mount *mp, + struct xfs_trans **tpp, + xfs_agnumber_t agno, + xfs_extlen_t delta) +{ + struct xfs_alloc_arg args = { + .tp = *tpp, + .mp = mp, + .type = XFS_ALLOCTYPE_THIS_BNO, + .minlen = delta, + .maxlen = delta, + .oinfo = XFS_RMAP_OINFO_SKIP_UPDATE, + .resv = XFS_AG_RESV_NONE, + .prod = 1 + }; + struct xfs_buf *agibp, *agfbp; + struct xfs_agi *agi; + struct xfs_agf *agf; + int error, err2; + + ASSERT(agno == mp->m_sb.sb_agcount - 1); + error = xfs_ialloc_read_agi(mp, *tpp, agno, &agibp); + if (error) + return error; + + agi = agibp->b_addr; + + error = xfs_alloc_read_agf(mp, *tpp, agno, 0, &agfbp); + if (error) + return error; + + agf = agfbp->b_addr; + /* some extra paranoid checks before we shrink the ag */ + if (XFS_IS_CORRUPT(mp, agf->agf_length != agi->agi_length)) + return -EFSCORRUPTED; + if (delta >= agi->agi_length) + return -EINVAL; + + args.fsbno = XFS_AGB_TO_FSB(mp, agno, + be32_to_cpu(agi->agi_length) - delta); + + /* + * Disable perag reservations so it doesn't cause the allocation request + * to fail. We'll reestablish reservation before we return. + */ + error = xfs_ag_resv_free(agibp->b_pag); + if (error) + return error; + + /* internal log shouldn't also show up in the free space btrees */ + error = xfs_alloc_vextent(&args); + if (!error && args.agbno == NULLAGBLOCK) + error = -ENOSPC; + + if (error) { + /* + * if extent allocation fails, need to roll the transaction to + * ensure that the AGFL fixup has been committed anyway. + */ + xfs_trans_bhold(*tpp, agfbp); + err2 = xfs_trans_roll(tpp); + if (err2) + return err2; + xfs_trans_bjoin(*tpp, agfbp); + goto resv_init_out; + } + + /* + * if successfully deleted from freespace btrees, need to confirm + * per-AG reservation works as expected. + */ + be32_add_cpu(&agi->agi_length, -delta); + be32_add_cpu(&agf->agf_length, -delta); + + err2 = xfs_ag_resv_init(agibp->b_pag, *tpp); + if (err2) { + be32_add_cpu(&agi->agi_length, delta); + be32_add_cpu(&agf->agf_length, delta); + if (err2 != -ENOSPC) + goto resv_err; + + __xfs_bmap_add_free(*tpp, args.fsbno, delta, NULL, true); + + /* + * Roll the transaction before trying to re-init the per-ag + * reservation. The new transaction is clean so it will cancel + * without any side effects. + */ + error = xfs_defer_finish(tpp); + if (error) + return error; + + error = -ENOSPC; + goto resv_init_out; + } + xfs_ialloc_log_agi(*tpp, agibp, XFS_AGI_LENGTH); + xfs_alloc_log_agf(*tpp, agfbp, XFS_AGF_LENGTH); + return 0; +resv_init_out: + err2 = xfs_ag_resv_init(agibp->b_pag, *tpp); + if (!err2) + return error; +resv_err: + xfs_warn(mp, "Error %d reserving per-AG metadata reserve pool.", err2); + xfs_force_shutdown(mp, SHUTDOWN_CORRUPT_INCORE); + return err2; +} + /* * Extent the AG indicated by the @id by the length passed in */ diff --git a/fs/xfs/libxfs/xfs_ag.h b/fs/xfs/libxfs/xfs_ag.h index 5166322807e7..4535de1d88ea 100644 --- a/fs/xfs/libxfs/xfs_ag.h +++ b/fs/xfs/libxfs/xfs_ag.h @@ -24,6 +24,8 @@ struct aghdr_init_data { }; int xfs_ag_init_headers(struct xfs_mount *mp, struct aghdr_init_data *id); +int xfs_ag_shrink_space(struct xfs_mount *mp, struct xfs_trans **tpp, + xfs_agnumber_t agno, xfs_extlen_t delta); int xfs_ag_extend_space(struct xfs_mount *mp, struct xfs_trans *tp, struct aghdr_init_data *id, xfs_extlen_t len); int xfs_ag_get_geometry(struct xfs_mount *mp, xfs_agnumber_t agno, -- 2.25.1