Re: [PATCH RFC] xfs: change agfl perag res into an rmapbt-based reservation
From: Brian Foster <hidden>
Date: 2018-02-01 21:43:47
On Wed, Jan 31, 2018 at 09:59:01AM -0500, Brian Foster wrote: ...
Signed-off-by: Brian Foster <redacted> --- This is RFC for the moment because I have reproduced a one-off sb_fdblocks inconsistency during xfstests. Unfortunately, I have not been able to reproduce that problem after several rmapbt/reflink enabled cycles so far. It's not yet clear to me if this is a bug in this patch or not, so more testing is required at minimum. I'm sending this out for thoughts in the meantime.
FYI - I've finally reproduced this particular problem and it triggered on a kernel without this patch applied, so I'm fairly confident it's unrelated. I still have to narrow down the reproducer, but I'll look into that independently. In the meantime I think it's safe to drop RFC status from this patch.. Brian
quoted hunk ↗ jump to hunk
Brian fs/xfs/libxfs/xfs_ag_resv.c | 39 ++++++++++++++++++++++----------------- fs/xfs/libxfs/xfs_ag_resv.h | 31 +++++++++++++++++++++++++++++++ fs/xfs/libxfs/xfs_alloc.c | 14 +++----------- fs/xfs/libxfs/xfs_rmap_btree.c | 4 ++++ fs/xfs/xfs_mount.h | 9 +++++---- fs/xfs/xfs_reflink.c | 2 +- 6 files changed, 66 insertions(+), 33 deletions(-)diff --git a/fs/xfs/libxfs/xfs_ag_resv.c b/fs/xfs/libxfs/xfs_ag_resv.c index 2291f4224e24..1945202426c4 100644 --- a/fs/xfs/libxfs/xfs_ag_resv.c +++ b/fs/xfs/libxfs/xfs_ag_resv.c@@ -95,13 +95,13 @@ xfs_ag_resv_critical( switch (type) { case XFS_AG_RESV_METADATA: - avail = pag->pagf_freeblks - pag->pag_agfl_resv.ar_reserved; + avail = pag->pagf_freeblks - pag->pag_rmapbt_resv.ar_reserved; orig = pag->pag_meta_resv.ar_asked; break; - case XFS_AG_RESV_AGFL: + case XFS_AG_RESV_RMAPBT: avail = pag->pagf_freeblks + pag->pagf_flcount - pag->pag_meta_resv.ar_reserved; - orig = pag->pag_agfl_resv.ar_asked; + orig = pag->pag_rmapbt_resv.ar_asked; break; default: ASSERT(0);@@ -126,10 +126,10 @@ xfs_ag_resv_needed( { xfs_extlen_t len; - len = pag->pag_meta_resv.ar_reserved + pag->pag_agfl_resv.ar_reserved; + len = pag->pag_meta_resv.ar_reserved + pag->pag_rmapbt_resv.ar_reserved; switch (type) { case XFS_AG_RESV_METADATA: - case XFS_AG_RESV_AGFL: + case XFS_AG_RESV_RMAPBT: len -= xfs_perag_resv(pag, type)->ar_reserved; break; case XFS_AG_RESV_NONE:@@ -160,10 +160,11 @@ __xfs_ag_resv_free( if (pag->pag_agno == 0) pag->pag_mount->m_ag_max_usable += resv->ar_asked; /* - * AGFL blocks are always considered "free", so whatever - * was reserved at mount time must be given back at umount. + * RMAPBT blocks come from the AGFL and AGFL blocks are always + * considered "free", so whatever was reserved at mount time must be + * given back at umount. */ - if (type == XFS_AG_RESV_AGFL) + if (type == XFS_AG_RESV_RMAPBT) oldresv = resv->ar_orig_reserved; else oldresv = resv->ar_reserved;@@ -185,7 +186,7 @@ xfs_ag_resv_free( int error; int err2; - error = __xfs_ag_resv_free(pag, XFS_AG_RESV_AGFL); + error = __xfs_ag_resv_free(pag, XFS_AG_RESV_RMAPBT); err2 = __xfs_ag_resv_free(pag, XFS_AG_RESV_METADATA); if (err2 && !error) error = err2;@@ -284,15 +285,15 @@ xfs_ag_resv_init( } } - /* Create the AGFL metadata reservation */ - if (pag->pag_agfl_resv.ar_asked == 0) { + /* Create the RMAPBT metadata reservation */ + if (pag->pag_rmapbt_resv.ar_asked == 0) { ask = used = 0; error = xfs_rmapbt_calc_reserves(mp, agno, &ask, &used); if (error) goto out; - error = __xfs_ag_resv_init(pag, XFS_AG_RESV_AGFL, ask, used); + error = __xfs_ag_resv_init(pag, XFS_AG_RESV_RMAPBT, ask, used); if (error) goto out; }@@ -304,7 +305,7 @@ xfs_ag_resv_init( return error; ASSERT(xfs_perag_resv(pag, XFS_AG_RESV_METADATA)->ar_reserved + - xfs_perag_resv(pag, XFS_AG_RESV_AGFL)->ar_reserved <= + xfs_perag_resv(pag, XFS_AG_RESV_RMAPBT)->ar_reserved <= pag->pagf_freeblks + pag->pagf_flcount); #endif out:@@ -325,8 +326,10 @@ xfs_ag_resv_alloc_extent( trace_xfs_ag_resv_alloc_extent(pag, type, args->len); switch (type) { - case XFS_AG_RESV_METADATA: case XFS_AG_RESV_AGFL: + return; + case XFS_AG_RESV_RMAPBT: + case XFS_AG_RESV_METADATA: resv = xfs_perag_resv(pag, type); break; default:@@ -341,7 +344,7 @@ xfs_ag_resv_alloc_extent( len = min_t(xfs_extlen_t, args->len, resv->ar_reserved); resv->ar_reserved -= len; - if (type == XFS_AG_RESV_AGFL) + if (type == XFS_AG_RESV_RMAPBT) return; /* Allocations of reserved blocks only need on-disk sb updates... */ xfs_trans_mod_sb(args->tp, XFS_TRANS_SB_RES_FDBLOCKS, -(int64_t)len);@@ -365,8 +368,10 @@ xfs_ag_resv_free_extent( trace_xfs_ag_resv_free_extent(pag, type, len); switch (type) { - case XFS_AG_RESV_METADATA: case XFS_AG_RESV_AGFL: + return; + case XFS_AG_RESV_RMAPBT: + case XFS_AG_RESV_METADATA: resv = xfs_perag_resv(pag, type); break; default:@@ -379,7 +384,7 @@ xfs_ag_resv_free_extent( leftover = min_t(xfs_extlen_t, len, resv->ar_asked - resv->ar_reserved); resv->ar_reserved += leftover; - if (type == XFS_AG_RESV_AGFL) + if (type == XFS_AG_RESV_RMAPBT) return; /* Freeing into the reserved pool only requires on-disk update... */ xfs_trans_mod_sb(tp, XFS_TRANS_SB_RES_FDBLOCKS, len);diff --git a/fs/xfs/libxfs/xfs_ag_resv.h b/fs/xfs/libxfs/xfs_ag_resv.h index 8d6c687deef3..938f2f96c5e8 100644 --- a/fs/xfs/libxfs/xfs_ag_resv.h +++ b/fs/xfs/libxfs/xfs_ag_resv.h@@ -32,4 +32,35 @@ void xfs_ag_resv_alloc_extent(struct xfs_perag *pag, enum xfs_ag_resv_type type, void xfs_ag_resv_free_extent(struct xfs_perag *pag, enum xfs_ag_resv_type type, struct xfs_trans *tp, xfs_extlen_t len); +/* + * RMAPBT reservation accounting wrappers. Since rmapbt blocks are sourced from + * the AGFL, they are allocated one at a time and the reservation updates don't + * require a transaction. + */ +static inline void +xfs_ag_resv_rmapbt_alloc( + struct xfs_mount *mp, + xfs_agnumber_t agno) +{ + struct xfs_alloc_arg args = {0}; + struct xfs_perag *pag; + + args.len = 1; + pag = xfs_perag_get(mp, agno); + xfs_ag_resv_alloc_extent(pag, XFS_AG_RESV_RMAPBT, &args); + xfs_perag_put(pag); +} + +static inline void +xfs_ag_resv_rmapbt_free( + struct xfs_mount *mp, + xfs_agnumber_t agno) +{ + struct xfs_perag *pag; + + pag = xfs_perag_get(mp, agno); + xfs_ag_resv_free_extent(pag, XFS_AG_RESV_RMAPBT, NULL, 1); + xfs_perag_put(pag); +} + #endif /* __XFS_AG_RESV_H__ */diff --git a/fs/xfs/libxfs/xfs_alloc.c b/fs/xfs/libxfs/xfs_alloc.c index c02781a4c091..8c401efb2d74 100644 --- a/fs/xfs/libxfs/xfs_alloc.c +++ b/fs/xfs/libxfs/xfs_alloc.c@@ -1564,7 +1564,6 @@ xfs_alloc_ag_vextent_small( int *stat) /* status: 0-freelist, 1-normal/none */ { struct xfs_owner_info oinfo; - struct xfs_perag *pag; int error; xfs_agblock_t fbno; xfs_extlen_t flen;@@ -1616,18 +1615,13 @@ xfs_alloc_ag_vextent_small( /* * If we're feeding an AGFL block to something that * doesn't live in the free space, we need to clear - * out the OWN_AG rmap and add the block back to - * the AGFL per-AG reservation. + * out the OWN_AG rmap. */ xfs_rmap_ag_owner(&oinfo, XFS_RMAP_OWN_AG); error = xfs_rmap_free(args->tp, args->agbp, args->agno, fbno, 1, &oinfo); if (error) goto error0; - pag = xfs_perag_get(args->mp, args->agno); - xfs_ag_resv_free_extent(pag, XFS_AG_RESV_AGFL, - args->tp, 1); - xfs_perag_put(pag); *stat = 0; return 0;@@ -1911,14 +1905,12 @@ xfs_free_ag_extent( XFS_STATS_INC(mp, xs_freex); XFS_STATS_ADD(mp, xs_freeb, len); - trace_xfs_free_extent(mp, agno, bno, len, type == XFS_AG_RESV_AGFL, - haveleft, haveright); + trace_xfs_free_extent(mp, agno, bno, len, type, haveleft, haveright); return 0; error0: - trace_xfs_free_extent(mp, agno, bno, len, type == XFS_AG_RESV_AGFL, - -1, -1); + trace_xfs_free_extent(mp, agno, bno, len, type, -1, -1); if (bno_cur) xfs_btree_del_cursor(bno_cur, XFS_BTREE_ERROR); if (cnt_cur)diff --git a/fs/xfs/libxfs/xfs_rmap_btree.c b/fs/xfs/libxfs/xfs_rmap_btree.c index e829c3e489ea..8560091554e0 100644 --- a/fs/xfs/libxfs/xfs_rmap_btree.c +++ b/fs/xfs/libxfs/xfs_rmap_btree.c@@ -130,6 +130,8 @@ xfs_rmapbt_alloc_block( be32_add_cpu(&agf->agf_rmap_blocks, 1); xfs_alloc_log_agf(cur->bc_tp, agbp, XFS_AGF_RMAP_BLOCKS); + xfs_ag_resv_rmapbt_alloc(cur->bc_mp, cur->bc_private.a.agno); + XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT); *stat = 1; return 0;@@ -158,6 +160,8 @@ xfs_rmapbt_free_block( XFS_EXTENT_BUSY_SKIP_DISCARD); xfs_trans_agbtree_delta(cur->bc_tp, -1); + xfs_ag_resv_rmapbt_free(cur->bc_mp, cur->bc_private.a.agno); + return 0; }diff --git a/fs/xfs/xfs_mount.h b/fs/xfs/xfs_mount.h index e0792d036be2..f659045507fb 100644 --- a/fs/xfs/xfs_mount.h +++ b/fs/xfs/xfs_mount.h@@ -327,6 +327,7 @@ xfs_daddr_to_agbno(struct xfs_mount *mp, xfs_daddr_t d) enum xfs_ag_resv_type { XFS_AG_RESV_NONE = 0, XFS_AG_RESV_METADATA, + XFS_AG_RESV_RMAPBT, XFS_AG_RESV_AGFL, };@@ -391,8 +392,8 @@ typedef struct xfs_perag { /* Blocks reserved for all kinds of metadata. */ struct xfs_ag_resv pag_meta_resv; - /* Blocks reserved for just AGFL-based metadata. */ - struct xfs_ag_resv pag_agfl_resv; + /* Blocks reserved for the reverse mapping btree. */ + struct xfs_ag_resv pag_rmapbt_resv; /* reference count */ uint8_t pagf_refcount_level;@@ -406,8 +407,8 @@ xfs_perag_resv( switch (type) { case XFS_AG_RESV_METADATA: return &pag->pag_meta_resv; - case XFS_AG_RESV_AGFL: - return &pag->pag_agfl_resv; + case XFS_AG_RESV_RMAPBT: + return &pag->pag_rmapbt_resv; default: return NULL; }diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c index 270246943a06..832df6f49ba1 100644 --- a/fs/xfs/xfs_reflink.c +++ b/fs/xfs/xfs_reflink.c@@ -1061,7 +1061,7 @@ xfs_reflink_ag_has_free_space( return 0; pag = xfs_perag_get(mp, agno); - if (xfs_ag_resv_critical(pag, XFS_AG_RESV_AGFL) || + if (xfs_ag_resv_critical(pag, XFS_AG_RESV_RMAPBT) || xfs_ag_resv_critical(pag, XFS_AG_RESV_METADATA)) error = -ENOSPC; xfs_perag_put(pag);-- 2.13.6 -- To unsubscribe from this list: send the line "unsubscribe linux-xfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html