[PATCH 052/119] xfs: set up per-AG free space reservations

Darrick J. Wong
2016-06-17T01:23:35Z

One unfortunate quirk of the reference count btree -- it can expand in
size when blocks are written to *other* allocation groups if, say, one
large extent becomes a lot of tiny extents. Since we don't want to
start throwing errors in the middle of CoWing, we need to reserve some
blocks to handle future expansion.

Use the count of how many reserved blocks we need to have on hand to
create a virtual reservation in the AG. Through selective clamping of
the maximum length of allocation requests and of the length of the
longest free extent, we can make it look like there's less free space
in the AG unless the reservation owner is asking for blocks.

In other words, play some accounting tricks in-core to make sure that
we always have blocks available. On the plus side, there's nothing to
clean up if we crash, which is contrast to the strategy that the rough
draft used (actually removing extents from the freespace btrees).

v2: There's really only two kinds of per-AG reservation pools -- one
to feed the AGFL (rmapbt), and one to feed everything else
(refcountbt). Bearing that in mind, we can embed the reservation
controls in xfs_perag and greatly simplify the block accounting.
Furthermore, fix some longstanding accounting bugs that were a direct
result of the goofy "allocate a block and later fix up the accounting"
strategy by integrating the reservation accounting code more tightly
with the allocator. This eliminates the ENOSPC complaints resulting
from refcount btree splits during truncate operations.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
fs/xfs/Makefile | 1
fs/xfs/libxfs/xfs_ag_resv.c | 318 ++++++++++++++++++++++++++++++++++++++
fs/xfs/libxfs/xfs_ag_resv.h | 35 ++++
fs/xfs/libxfs/xfs_alloc.c | 93 ++++++++---
fs/xfs/libxfs/xfs_alloc.h | 8 +
fs/xfs/libxfs/xfs_bmap.c | 6 -
fs/xfs/libxfs/xfs_ialloc_btree.c | 2
fs/xfs/xfs_filestream.c | 4
fs/xfs/xfs_fsops.c | 2
fs/xfs/xfs_mount.h | 34 ++++
fs/xfs/xfs_trace.h | 36 +---
fs/xfs/xfs_trans_extfree.c | 3
12 files changed, 485 insertions(+), 57 deletions(-)
create mode 100644 fs/xfs/libxfs/xfs_ag_resv.c
create mode 100644 fs/xfs/libxfs/xfs_ag_resv.h

diff --git a/fs/xfs/Makefile b/fs/xfs/Makefile
index 1980110..c7a864e 100644
--- a/fs/xfs/Makefile
+++ b/fs/xfs/Makefile
@@ -52,6 +52,7 @@ xfs-y += $(addprefix libxfs/, \
xfs_inode_fork.o \
xfs_inode_buf.o \
xfs_log_rlimit.o \
+ xfs_ag_resv.o \
xfs_rmap.o \
xfs_rmap_btree.o \
xfs_sb.o \
diff --git a/fs/xfs/libxfs/xfs_ag_resv.c b/fs/xfs/libxfs/xfs_ag_resv.c
new file mode 100644
index 0000000..4d390b7
--- /dev/null
+++ b/fs/xfs/libxfs/xfs_ag_resv.c
@@ -0,0 +1,318 @@
+/*
+ * Copyright (C) 2016 Oracle. All Rights Reserved.
+ *
+ * Author: Darrick J. Wong <darrick.wong@oracle.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it would be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.
+ */
+#include "xfs.h"
+#include "xfs_fs.h"
+#include "xfs_shared.h"
+#include "xfs_format.h"
+#include "xfs_log_format.h"
+#include "xfs_trans_resv.h"
+#include "xfs_sb.h"
+#include "xfs_mount.h"
+#include "xfs_defer.h"
+#include "xfs_alloc.h"
+#include "xfs_error.h"
+#include "xfs_trace.h"
+#include "xfs_cksum.h"
+#include "xfs_trans.h"
+#include "xfs_bit.h"
+#include "xfs_bmap.h"
+#include "xfs_bmap_btree.h"
+#include "xfs_ag_resv.h"
+#include "xfs_trans_space.h"
+#include "xfs_rmap_btree.h"
+#include "xfs_btree.h"
+
+/*
+ * Per-AG Block Reservations
+ *
+ * For some kinds of allocation group metadata structures, it is advantageous
+ * to reserve a small number of blocks in each AG so that future expansions of
+ * that data structure do not encounter ENOSPC because errors during a btree
+ * split cause the filesystem to go offline.
+ *
+ * Prior to the introduction of reflink, this wasn't an issue because the free
+ * space btrees maintain a reserve of space (the AGFL) to handle any expansion
+ * that may be necessary; and allocations of other metadata (inodes, BMBT,
+ * dir/attr) aren't restricted to a single AG. However, with reflink it is
+ * possible to allocate all the space in an AG, have subsequent reflink/CoW
+ * activity expand the refcount btree, and discover that there's no space left
+ * to handle that expansion. Since we can calculate the maximum size of the
+ * refcount btree, we can reserve space for it and avoid ENOSPC.
+ *
+ * Handling per-AG reservations consists of three changes to the allocator's
+ * behavior: First, because these reservations are always needed, we decrease
+ * the ag_max_usable counter to reflect the size of the AG after the reserved
+ * blocks are taken. Second, the reservations must be reflected in the
+ * fdblocks count to maintain proper accounting. Third, each AG must maintain
+ * its own reserved block counter so that we can calculate the amount of space
+ * that must remain free to maintain the reservations. Fourth, the "remaining
+ * reserved blocks" count must be used when calculating the length of the
+ * longest free extent in an AG and to clamp maxlen in the per-AG allocation
+ * functions. In other words, we maintain a virtual allocation via in-core
+ * accounting tricks so that we don't have to clean up after a crash. :)
+ *
+ * Reserved blocks can be managed by passing one of the enum xfs_ag_resv_type
+ * values via struct xfs_alloc_arg or directly to the xfs_free_extent
+ * function. It might seem a little funny to maintain a reservoir of blocks
+ * to feed another reservoir, but the AGFL only holds enough blocks to get
+ * through the next transaction. The per-AG reservation is to ensure (we
+ * hope) that each AG never runs out of blocks. Each data structure wanting
+ * to use the reservation system should update ask/used in xfs_ag_resv_init.
+ */
+
+/*
+ * Are we critically low on blocks? For now we'll define that as the number
+ * of blocks we can get our hands on being less than 10% of what we reserved
+ * or less than some arbitrary number (eight).
+ */
+bool
+xfs_ag_resv_critical(
+ struct xfs_perag *pag,
+ enum xfs_ag_resv_type type)
+{
+ xfs_extlen_t avail;
+ xfs_extlen_t orig;
+
+ switch (type) {
+ case XFS_AG_RESV_METADATA:
+ avail = pag->pagf_freeblks - pag->pag_agfl_resv.ar_reserved;
+ orig = pag->pag_meta_resv.ar_asked;
+ break;
+ case XFS_AG_RESV_AGFL:
+ avail = pag->pagf_freeblks + pag->pagf_flcount -
+ pag->pag_meta_resv.ar_reserved;
+ orig = pag->pag_agfl_resv.ar_asked;
+ break;
+ default:
+ ASSERT(0);
+ return false;
+ }
+
+ trace_xfs_ag_resv_critical(pag, type, avail);
+
+ return avail < orig / 10 || avail < XFS_BTREE_MAXLEVELS;
+}
+
+/*
+ * How many blocks are reserved but not used, and therefore must not be
+ * allocated away?
+ */
+xfs_extlen_t
+xfs_ag_resv_needed(
+ struct xfs_perag *pag,
+ enum xfs_ag_resv_type type)
+{
+ xfs_extlen_t len;
+
+ len = pag->pag_meta_resv.ar_reserved + pag->pag_agfl_resv.ar_reserved;
+ switch (type) {
+ case XFS_AG_RESV_METADATA:
+ case XFS_AG_RESV_AGFL:
+ len -= xfs_perag_resv(pag, type)->ar_reserved;
+ break;
+ case XFS_AG_RESV_NONE:
+ /* empty */
+ break;
+ default:
+ ASSERT(0);
+ }
+
+ trace_xfs_ag_resv_needed(pag, type, len);
+
+ return len;
+}
+
+/* Clean out a reservation */
+static int
+__xfs_ag_resv_free(
+ struct xfs_perag *pag,
+ enum xfs_ag_resv_type type)
+{
+ struct xfs_ag_resv *resv;
+ struct xfs_ag_resv t;
+ int error;
+
+ trace_xfs_ag_resv_free(pag, type, 0);
+
+ resv = xfs_perag_resv(pag, type);
+ t = *resv;
+ resv->ar_reserved = 0;
+ resv->ar_asked = 0;
+ pag->pag_mount->m_ag_max_usable += t.ar_asked;
+
+ error = xfs_mod_fdblocks(pag->pag_mount, t.ar_reserved, true);
+ if (error)
+ trace_xfs_ag_resv_free_error(pag->pag_mount, pag->pag_agno,
+ error, _RET_IP_);
+ return error;
+}
+
+/* Free a per-AG reservation. */
+int
+xfs_ag_resv_free(
+ struct xfs_perag *pag)
+{
+ int error = 0;
+ int err2;
+
+ err2 = __xfs_ag_resv_free(pag, XFS_AG_RESV_AGFL);
+ if (err2 && !error)
+ error = err2;
+ err2 = __xfs_ag_resv_free(pag, XFS_AG_RESV_METADATA);
+ if (err2 && !error)
+ error = err2;
+ return error;
+}
+
+static int
+__xfs_ag_resv_init(
+ struct xfs_perag *pag,
+ enum xfs_ag_resv_type type,
+ xfs_extlen_t ask,
+ xfs_extlen_t used)
+{
+ struct xfs_mount *mp = pag->pag_mount;
+ struct xfs_ag_resv *resv;
+ int error;
+
+ resv = xfs_perag_resv(pag, type);
+ if (used > ask)
+ ask = used;
+ resv->ar_asked = ask;
+ resv->ar_reserved = ask - used;
+ mp->m_ag_max_usable -= ask;
+
+ trace_xfs_ag_resv_init(pag, type, ask);
+
+ error = xfs_mod_fdblocks(mp, -(int64_t)resv->ar_reserved, true);
+ if (error)
+ trace_xfs_ag_resv_init_error(pag->pag_mount, pag->pag_agno,
+ error, _RET_IP_);
+
+ return error;
+}
+
+/* Create a per-AG block reservation. */
+int
+xfs_ag_resv_init(
+ struct xfs_perag *pag)
+{
+ xfs_extlen_t ask;
+ xfs_extlen_t used;
+ int error = 0;
+ int err2;
+
+ if (pag->pag_meta_resv.ar_asked)
+ goto init_agfl;
+
+ /* Create the metadata reservation. */
+ ask = used = 0;
+
+ err2 = __xfs_ag_resv_init(pag, XFS_AG_RESV_METADATA, ask, used);
+ if (err2 && !error)
+ error = err2;
+
+init_agfl:
+ if (pag->pag_agfl_resv.ar_asked)
+ return error;
+
+ /* Create the AGFL metadata reservation */
+ ask = used = 0;
+
+ err2 = __xfs_ag_resv_init(pag, XFS_AG_RESV_AGFL, ask, used);
+ if (err2 && !error)
+ error = err2;
+
+ return error;
+}
+
+/* Allocate a block from the reservation. */
+void
+xfs_ag_resv_alloc_extent(
+ struct xfs_perag *pag,
+ enum xfs_ag_resv_type type,
+ struct xfs_alloc_arg *args)
+{
+ struct xfs_ag_resv *resv;
+ xfs_extlen_t leftover;
+ uint field;
+
+ trace_xfs_ag_resv_alloc_extent(pag, type, args->len);
+
+ switch (type) {
+ case XFS_AG_RESV_METADATA:
+ case XFS_AG_RESV_AGFL:
+ resv = xfs_perag_resv(pag, type);
+ break;
+ default:
+ ASSERT(0);
+ /* fall through */
+ case XFS_AG_RESV_NONE:
+ field = args->wasdel ? XFS_TRANS_SB_RES_FDBLOCKS :
+ XFS_TRANS_SB_FDBLOCKS;
+ xfs_trans_mod_sb(args->tp, field, -(int64_t)args->len);
+ return;
+ }
+
+ if (args->len > resv->ar_reserved) {
+ leftover = args->len - resv->ar_reserved;
+ if (type != XFS_AG_RESV_AGFL)
+ xfs_trans_mod_sb(args->tp, XFS_TRANS_SB_FDBLOCKS,
+ -(int64_t)leftover);
+ resv->ar_reserved = 0;
+ } else
+ resv->ar_reserved -= args->len;
+}
+
+/* Free a block to the reservation. */
+void
+xfs_ag_resv_free_extent(
+ struct xfs_perag *pag,
+ enum xfs_ag_resv_type type,
+ struct xfs_trans *tp,
+ xfs_extlen_t len)
+{
+ xfs_extlen_t leftover;
+ struct xfs_ag_resv *resv;
+
+ trace_xfs_ag_resv_free_extent(pag, type, len);
+
+ switch (type) {
+ case XFS_AG_RESV_METADATA:
+ case XFS_AG_RESV_AGFL:
+ resv = xfs_perag_resv(pag, type);
+ break;
+ default:
+ ASSERT(0);
+ /* fall through */
+ case XFS_AG_RESV_NONE:
+ xfs_trans_mod_sb(tp, XFS_TRANS_SB_FDBLOCKS, (int64_t)len);
+ return;
+ }
+
+ if (resv->ar_reserved + len > resv->ar_asked) {
+ leftover = resv->ar_reserved + len - resv->ar_asked;
+ if (type != XFS_AG_RESV_AGFL)
+ xfs_trans_mod_sb(tp, XFS_TRANS_SB_FDBLOCKS,
+ (int64_t)leftover);
+ resv->ar_reserved = resv->ar_asked;
+ } else
+ resv->ar_reserved += len;
+}
diff --git a/fs/xfs/libxfs/xfs_ag_resv.h b/fs/xfs/libxfs/xfs_ag_resv.h
new file mode 100644
index 0000000..8d6c687
--- /dev/null
+++ b/fs/xfs/libxfs/xfs_ag_resv.h
@@ -0,0 +1,35 @@
+/*
+ * Copyright (C) 2016 Oracle. All Rights Reserved.
+ *
+ * Author: Darrick J. Wong <darrick.wong@oracle.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it would be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.
+ */
+#ifndef __XFS_AG_RESV_H__
+#define __XFS_AG_RESV_H__
+
+int xfs_ag_resv_free(struct xfs_perag *pag);
+int xfs_ag_resv_init(struct xfs_perag *pag);
+
+bool xfs_ag_resv_critical(struct xfs_perag *pag, enum xfs_ag_resv_type type);
+xfs_extlen_t xfs_ag_resv_needed(struct xfs_perag *pag,
+ enum xfs_ag_resv_type type);
+
+void xfs_ag_resv_alloc_extent(struct xfs_perag *pag, enum xfs_ag_resv_type type,
+ struct xfs_alloc_arg *args);
+void xfs_ag_resv_free_extent(struct xfs_perag *pag, enum xfs_ag_resv_type type,
+ struct xfs_trans *tp, xfs_extlen_t len);
+
+#endif /* __XFS_AG_RESV_H__ */
diff --git a/fs/xfs/libxfs/xfs_alloc.c b/fs/xfs/libxfs/xfs_alloc.c
index 6eabab1..5f05c4e 100644
--- a/fs/xfs/libxfs/xfs_alloc.c
+++ b/fs/xfs/libxfs/xfs_alloc.c
@@ -37,6 +37,7 @@
#include "xfs_trans.h"
#include "xfs_buf_item.h"
#include "xfs_log.h"
+#include "xfs_ag_resv.h"

struct workqueue_struct *xfs_alloc_wq;

@@ -682,12 +683,29 @@ xfs_alloc_ag_vextent(
xfs_alloc_arg_t *args) /* argument structure for allocation */
{
int error=0;
+ xfs_extlen_t reservation;
+ xfs_extlen_t oldmax;

ASSERT(args->minlen > 0);
ASSERT(args->maxlen > 0);
ASSERT(args->minlen <= args->maxlen);
ASSERT(args->mod < args->prod);
ASSERT(args->alignment > 0);
+
+ /*
+ * Clamp maxlen to the amount of free space minus any reservations
+ * that have been made.
+ */
+ oldmax = args->maxlen;
+ reservation = xfs_ag_resv_needed(args->pag, args->resv);
+ if (args->maxlen > args->pag->pagf_freeblks - reservation)
+ args->maxlen = args->pag->pagf_freeblks - reservation;
+ if (args->maxlen == 0) {
+ args->agbno = NULLAGBLOCK;
+ args->maxlen = oldmax;
+ return 0;
+ }
+
/*
* Branch to correct routine based on the type.
*/
@@ -707,12 +725,14 @@ xfs_alloc_ag_vextent(
/* NOTREACHED */
}

+ args->maxlen = oldmax;
+
if (error || args->agbno == NULLAGBLOCK)
return error;

ASSERT(args->len >= args->minlen);
ASSERT(args->len <= args->maxlen);
- ASSERT(!args->wasfromfl || !args->isfl);
+ ASSERT(!args->wasfromfl || args->resv != XFS_AG_RESV_AGFL);
ASSERT(args->agbno % args->alignment == 0);

/* if not file data, insert new block into the reverse map btree */
@@ -734,12 +754,7 @@ xfs_alloc_ag_vextent(
args->agbno, args->len));
}

- if (!args->isfl) {
- xfs_trans_mod_sb(args->tp, args->wasdel ?
- XFS_TRANS_SB_RES_FDBLOCKS :
- XFS_TRANS_SB_FDBLOCKS,
- -((long)(args->len)));
- }
+ xfs_ag_resv_alloc_extent(args->pag, args->resv, args);

XFS_STATS_INC(args->mp, xs_allocx);
XFS_STATS_ADD(args->mp, xs_allocb, args->len);
@@ -1601,7 +1616,8 @@ xfs_alloc_ag_vextent_small(
* to respect minleft even when pulling from the
* freelist.
*/
- else if (args->minlen == 1 && args->alignment == 1 && !args->isfl &&
+ else if (args->minlen == 1 && args->alignment == 1 &&
+ args->resv != XFS_AG_RESV_AGFL &&
(be32_to_cpu(XFS_BUF_TO_AGF(args->agbp)->agf_flcount)
> args->minleft)) {
error = xfs_alloc_get_freelist(args->tp, args->agbp, &fbno, 0);
@@ -1672,7 +1688,7 @@ xfs_free_ag_extent(
xfs_agblock_t bno, /* starting block number */
xfs_extlen_t len, /* length of extent */
struct xfs_owner_info *oinfo, /* extent owner */
- int isfl) /* set if is freelist blocks - no sb acctg */
+ enum xfs_ag_resv_type type) /* extent reservation type */
{
xfs_btree_cur_t *bno_cur; /* cursor for by-block btree */
xfs_btree_cur_t *cnt_cur; /* cursor for by-size btree */
@@ -1900,21 +1916,22 @@ xfs_free_ag_extent(
*/
pag = xfs_perag_get(mp, agno);
error = xfs_alloc_update_counters(tp, pag, agbp, len);
+ xfs_ag_resv_free_extent(pag, type, tp, len);
xfs_perag_put(pag);
if (error)
goto error0;

- if (!isfl)
- xfs_trans_mod_sb(tp, XFS_TRANS_SB_FDBLOCKS, (long)len);
XFS_STATS_INC(mp, xs_freex);
XFS_STATS_ADD(mp, xs_freeb, len);

- trace_xfs_free_extent(mp, agno, bno, len, isfl, haveleft, haveright);
+ trace_xfs_free_extent(mp, agno, bno, len, type == XFS_AG_RESV_AGFL,
+ haveleft, haveright);

return 0;

error0:
- trace_xfs_free_extent(mp, agno, bno, len, isfl, -1, -1);
+ trace_xfs_free_extent(mp, agno, bno, len, type == XFS_AG_RESV_AGFL,
+ -1, -1);
if (bno_cur)
xfs_btree_del_cursor(bno_cur, XFS_BTREE_ERROR);
if (cnt_cur)
@@ -1939,21 +1956,43 @@ xfs_alloc_compute_maxlevels(
}

/*
- * Find the length of the longest extent in an AG.
+ * Find the length of the longest extent in an AG. The 'need' parameter
+ * specifies how much space we're going to need for the AGFL and the
+ * 'reserved' parameter tells us how many blocks in this AG are reserved for
+ * other callers.
*/
xfs_extlen_t
xfs_alloc_longest_free_extent(
struct xfs_mount *mp,
struct xfs_perag *pag,
- xfs_extlen_t need)
+ xfs_extlen_t need,
+ xfs_extlen_t reserved)
{
xfs_extlen_t delta = 0;

+ /*
+ * If the AGFL needs a recharge, we'll have to subtract that from the
+ * longest extent.
+ */
if (need > pag->pagf_flcount)
delta = need - pag->pagf_flcount;

+ /*
+ * If we cannot maintain others' reservations with space from the
+ * not-longest freesp extents, we'll have to subtract /that/ from
+ * the longest extent too.
+ */
+ if (pag->pagf_freeblks - pag->pagf_longest < reserved)
+ delta += reserved - (pag->pagf_freeblks - pag->pagf_longest);
+
+ /*
+ * If the longest extent is long enough to satisfy all the
+ * reservations and AGFL rules in place, we can return this extent.
+ */
if (pag->pagf_longest > delta)
return pag->pagf_longest - delta;
+
+ /* Otherwise, let the caller try for 1 block if there's space. */
return pag->pagf_flcount > 0 || pag->pagf_longest > 0;
}

@@ -1993,20 +2032,24 @@ xfs_alloc_space_available(
{
struct xfs_perag *pag = args->pag;
xfs_extlen_t longest;
+ xfs_extlen_t reservation; /* blocks that are still reserved */
int available;

if (flags & XFS_ALLOC_FLAG_FREEING)
return true;

+ reservation = xfs_ag_resv_needed(pag, args->resv);
+
/* do we have enough contiguous free space for the allocation? */
- longest = xfs_alloc_longest_free_extent(args->mp, pag, min_free);
+ longest = xfs_alloc_longest_free_extent(args->mp, pag, min_free,
+ reservation);
if ((args->minlen + args->alignment + args->minalignslop - 1) > longest)
return false;

- /* do have enough free space remaining for the allocation? */
+ /* do we have enough free space remaining for the allocation? */
available = (int)(pag->pagf_freeblks + pag->pagf_flcount -
- min_free - args->total);
- if (available < (int)args->minleft)
+ reservation - min_free - args->total);
+ if (available < (int)args->minleft || available <= 0)
return false;

return true;
@@ -2112,7 +2155,8 @@ xfs_alloc_fix_freelist(
if (error)
goto out_agbp_relse;
error = xfs_free_ag_extent(tp, agbp, args->agno, bno, 1,
- &targs.oinfo, 1);
+ &targs.oinfo,
+ XFS_AG_RESV_AGFL);
if (error)
goto out_agbp_relse;
bp = xfs_btree_get_bufs(mp, tp, args->agno, bno, 0);
@@ -2126,7 +2170,7 @@ xfs_alloc_fix_freelist(
xfs_rmap_ag_owner(&targs.oinfo, XFS_RMAP_OWN_AG);
targs.agbp = agbp;
targs.agno = args->agno;
- targs.alignment = targs.minlen = targs.prod = targs.isfl = 1;
+ targs.alignment = targs.minlen = targs.prod = 1;
targs.type = XFS_ALLOCTYPE_THIS_AG;
targs.pag = pag;
error = xfs_alloc_read_agfl(mp, tp, targs.agno, &agflbp);
@@ -2137,6 +2181,7 @@ xfs_alloc_fix_freelist(
while (pag->pagf_flcount < need) {
targs.agbno = 0;
targs.maxlen = need - pag->pagf_flcount;
+ targs.resv = XFS_AG_RESV_AGFL;

/* Allocate as many blocks as possible at once. */
error = xfs_alloc_ag_vextent(&targs);
@@ -2815,7 +2860,8 @@ xfs_free_extent(
struct xfs_trans *tp, /* transaction pointer */
xfs_fsblock_t bno, /* starting block number of extent */
xfs_extlen_t len, /* length of extent */
- struct xfs_owner_info *oinfo) /* extent owner */
+ struct xfs_owner_info *oinfo, /* extent owner */
+ enum xfs_ag_resv_type type) /* block reservation type */
{
struct xfs_mount *mp = tp->t_mountp;
struct xfs_buf *agbp;
@@ -2824,6 +2870,7 @@ xfs_free_extent(
int error;

ASSERT(len != 0);
+ ASSERT(type != XFS_AG_RESV_AGFL);

trace_xfs_bmap_free_deferred(mp, agno, 0, agbno, len);

@@ -2843,7 +2890,7 @@ xfs_free_extent(
agbno + len <= be32_to_cpu(XFS_BUF_TO_AGF(agbp)->agf_length),
err);

- error = xfs_free_ag_extent(tp, agbp, agno, agbno, len, oinfo, 0);
+ error = xfs_free_ag_extent(tp, agbp, agno, agbno, len, oinfo, type);
if (error)
goto err;

diff --git a/fs/xfs/libxfs/xfs_alloc.h b/fs/xfs/libxfs/xfs_alloc.h
index 7b9e67e..9f6373a4 100644
--- a/fs/xfs/libxfs/xfs_alloc.h
+++ b/fs/xfs/libxfs/xfs_alloc.h
@@ -87,10 +87,10 @@ typedef struct xfs_alloc_arg {
xfs_alloctype_t otype; /* original allocation type */
char wasdel; /* set if allocation was prev delayed */
char wasfromfl; /* set if allocation is from freelist */
- char isfl; /* set if is freelist blocks - !acctg */
char userdata; /* mask defining userdata treatment */
xfs_fsblock_t firstblock; /* io first block allocated */
struct xfs_owner_info oinfo; /* owner of blocks being allocated */
+ enum xfs_ag_resv_type resv; /* block reservation to use */
} xfs_alloc_arg_t;

/*
@@ -106,7 +106,8 @@ unsigned int xfs_alloc_set_aside(struct xfs_mount *mp);
unsigned int xfs_alloc_ag_max_usable(struct xfs_mount *mp);

xfs_extlen_t xfs_alloc_longest_free_extent(struct xfs_mount *mp,
- struct xfs_perag *pag, xfs_extlen_t need);
+ struct xfs_perag *pag, xfs_extlen_t need,
+ xfs_extlen_t reserved);
unsigned int xfs_alloc_min_freelist(struct xfs_mount *mp,
struct xfs_perag *pag);

@@ -184,7 +185,8 @@ xfs_free_extent(
struct xfs_trans *tp, /* transaction pointer */
xfs_fsblock_t bno, /* starting block number of extent */
xfs_extlen_t len, /* length of extent */
- struct xfs_owner_info *oinfo); /* extent owner */
+ struct xfs_owner_info *oinfo, /* extent owner */
+ enum xfs_ag_resv_type type); /* block reservation type */

int /* error */
xfs_alloc_lookup_ge(
diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
index 507fd74..972dfc2 100644
--- a/fs/xfs/libxfs/xfs_bmap.c
+++ b/fs/xfs/libxfs/xfs_bmap.c
@@ -47,6 +47,7 @@
#include "xfs_attr_leaf.h"
#include "xfs_filestream.h"
#include "xfs_rmap_btree.h"
+#include "xfs_ag_resv.h"

kmem_zone_t *xfs_bmap_free_item_zone;
@@ -3501,7 +3502,8 @@ xfs_bmap_longest_free_extent(
}

longest = xfs_alloc_longest_free_extent(mp, pag,
- xfs_alloc_min_freelist(mp, pag));
+ xfs_alloc_min_freelist(mp, pag),
+ xfs_ag_resv_needed(pag, XFS_AG_RESV_NONE));
if (*blen < longest)
*blen = longest;

@@ -3780,7 +3782,7 @@ xfs_bmap_btalloc(
}
args.minleft = ap->minleft;
args.wasdel = ap->wasdel;
- args.isfl = 0;
+ args.resv = XFS_AG_RESV_NONE;
args.userdata = ap->userdata;
if (ap->userdata & XFS_ALLOC_USERDATA_ZERO)
args.ip = ap->ip;
diff --git a/fs/xfs/libxfs/xfs_ialloc_btree.c b/fs/xfs/libxfs/xfs_ialloc_btree.c
index f9ea86b..fd26550 100644
--- a/fs/xfs/libxfs/xfs_ialloc_btree.c
+++ b/fs/xfs/libxfs/xfs_ialloc_btree.c
@@ -131,7 +131,7 @@ xfs_inobt_free_block(
xfs_rmap_ag_owner(&oinfo, XFS_RMAP_OWN_INOBT);
return xfs_free_extent(cur->bc_tp,
XFS_DADDR_TO_FSB(cur->bc_mp, XFS_BUF_ADDR(bp)), 1,
- &oinfo);
+ &oinfo, XFS_AG_RESV_NONE);
}

STATIC int
diff --git a/fs/xfs/xfs_filestream.c b/fs/xfs/xfs_filestream.c
index 4a33a33..c8005fd 100644
--- a/fs/xfs/xfs_filestream.c
+++ b/fs/xfs/xfs_filestream.c
@@ -30,6 +30,7 @@
#include "xfs_mru_cache.h"
#include "xfs_filestream.h"
#include "xfs_trace.h"
+#include "xfs_ag_resv.h"

struct xfs_fstrm_item {
struct xfs_mru_cache_elem mru;
@@ -198,7 +199,8 @@ xfs_filestream_pick_ag(
}

longest = xfs_alloc_longest_free_extent(mp, pag,
- xfs_alloc_min_freelist(mp, pag));
+ xfs_alloc_min_freelist(mp, pag),
+ xfs_ag_resv_needed(pag, XFS_AG_RESV_NONE));
if (((minlen && longest >= minlen) ||
(!minlen && pag->pagf_freeblks >= minfree)) &&
(!pag->pagf_metadata || !(flags & XFS_PICK_USERDATA) ||
diff --git a/fs/xfs/xfs_fsops.c b/fs/xfs/xfs_fsops.c
index 5980d5c..cd4de75 100644
--- a/fs/xfs/xfs_fsops.c
+++ b/fs/xfs/xfs_fsops.c
@@ -551,7 +551,7 @@ xfs_growfs_data_private(
error = xfs_free_extent(tp,
XFS_AGB_TO_FSB(mp, agno,
be32_to_cpu(agf->agf_length) - new),
- new, &oinfo);
+ new, &oinfo, XFS_AG_RESV_NONE);
if (error)
goto error0;
}
diff --git a/fs/xfs/xfs_mount.h b/fs/xfs/xfs_mount.h
index b36676c..e18d74e 100644
--- a/fs/xfs/xfs_mount.h
+++ b/fs/xfs/xfs_mount.h
@@ -325,6 +325,20 @@ xfs_mp_fail_writes(struct xfs_mount *mp)
}
#endif

+/* per-AG block reservation data structures*/
+enum xfs_ag_resv_type {
+ XFS_AG_RESV_NONE = 0,
+ XFS_AG_RESV_METADATA,
+ XFS_AG_RESV_AGFL,
+};
+
+struct xfs_ag_resv {
+ /* number of block reserved here */
+ xfs_extlen_t ar_reserved;
+ /* number of blocks originally asked for */
+ xfs_extlen_t ar_asked;
+};
+
/*
* Per-ag incore structure, copies of information in agf and agi, to improve the
* performance of allocation group selection.
@@ -372,8 +386,28 @@ typedef struct xfs_perag {
/* for rcu-safe freeing */
struct rcu_head rcu_head;
int pagb_count; /* pagb slots in use */
+
+ /* 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;
} xfs_perag_t;

+static inline struct xfs_ag_resv *
+xfs_perag_resv(
+ struct xfs_perag *pag,
+ enum xfs_ag_resv_type type)
+{
+ switch (type) {
+ case XFS_AG_RESV_METADATA:
+ return &pag->pag_meta_resv;
+ case XFS_AG_RESV_AGFL:
+ return &pag->pag_agfl_resv;
+ default:
+ return NULL;
+ }
+}
+
extern void xfs_uuid_table_free(void);
extern int xfs_log_sbcount(xfs_mount_t *);
extern __uint64_t xfs_default_resblks(xfs_mount_t *mp);
diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h
index c50479a..b421b28 100644
--- a/fs/xfs/xfs_trace.h
+++ b/fs/xfs/xfs_trace.h
@@ -1569,14 +1569,15 @@ TRACE_EVENT(xfs_agf,

TRACE_EVENT(xfs_free_extent,
TP_PROTO(struct xfs_mount *mp, xfs_agnumber_t agno, xfs_agblock_t agbno,
- xfs_extlen_t len, bool isfl, int haveleft, int haveright),
- TP_ARGS(mp, agno, agbno, len, isfl, haveleft, haveright),
+ xfs_extlen_t len, enum xfs_ag_resv_type resv, int haveleft,
+ int haveright),
+ TP_ARGS(mp, agno, agbno, len, resv, haveleft, haveright),
TP_STRUCT__entry(
__field(dev_t, dev)
__field(xfs_agnumber_t, agno)
__field(xfs_agblock_t, agbno)
__field(xfs_extlen_t, len)
- __field(int, isfl)
+ __field(int, resv)
__field(int, haveleft)
__field(int, haveright)
),
@@ -1585,16 +1586,16 @@ TRACE_EVENT(xfs_free_extent,
__entry->agno = agno;
__entry->agbno = agbno;
__entry->len = len;
- __entry->isfl = isfl;
+ __entry->resv = resv;
__entry->haveleft = haveleft;
__entry->haveright = haveright;
),
- TP_printk("dev %d:%d agno %u agbno %u len %u isfl %d %s",
+ TP_printk("dev %d:%d agno %u agbno %u len %u resv %d %s",
MAJOR(__entry->dev), MINOR(__entry->dev),
__entry->agno,
__entry->agbno,
__entry->len,
- __entry->isfl,
+ __entry->resv,
__entry->haveleft ?
(__entry->haveright ? "both" : "left") :
(__entry->haveright ? "right" : "none"))
@@ -1621,7 +1622,7 @@ DECLARE_EVENT_CLASS(xfs_alloc_class,
__field(short, otype)
__field(char, wasdel)
__field(char, wasfromfl)
- __field(char, isfl)
+ __field(int, resv)
__field(char, userdata)
__field(xfs_fsblock_t, firstblock)
),
@@ -1642,13 +1643,13 @@ DECLARE_EVENT_CLASS(xfs_alloc_class,
__entry->otype = args->otype;
__entry->wasdel = args->wasdel;
__entry->wasfromfl = args->wasfromfl;
- __entry->isfl = args->isfl;
+ __entry->resv = args->resv;
__entry->userdata = args->userdata;
__entry->firstblock = args->firstblock;
),
TP_printk("dev %d:%d agno %u agbno %u minlen %u maxlen %u mod %u "
"prod %u minleft %u total %u alignment %u minalignslop %u "
- "len %u type %s otype %s wasdel %d wasfromfl %d isfl %d "
+ "len %u type %s otype %s wasdel %d wasfromfl %d resv %d "
"userdata %d firstblock 0x%llx",
MAJOR(__entry->dev), MINOR(__entry->dev),
__entry->agno,
@@ -1666,7 +1667,7 @@ DECLARE_EVENT_CLASS(xfs_alloc_class,
__print_symbolic(__entry->otype, XFS_ALLOC_TYPES),
__entry->wasdel,
__entry->wasfromfl,
- __entry->isfl,
+ __entry->resv,
__entry->userdata,
(unsigned long long)__entry->firstblock)
)
@@ -2558,21 +2559,6 @@ DEFINE_RMAPBT_EVENT(xfs_rmap_map_gtrec);
DEFINE_RMAPBT_EVENT(xfs_rmap_convert_gtrec);
DEFINE_RMAPBT_EVENT(xfs_rmap_find_left_neighbor_result);

-/* dummy definitions to avoid breaking bisectability; will be removed later */
-#ifndef XFS_AG_RESV_DUMMY
-#define XFS_AG_RESV_DUMMY
-enum xfs_ag_resv_type {
- XFS_AG_RESV_NONE = 0,
- XFS_AG_RESV_METADATA,
- XFS_AG_RESV_AGFL,
-};
-struct xfs_ag_resv {
- xfs_extlen_t ar_reserved;
- xfs_extlen_t ar_asked;
-};
-#define xfs_perag_resv(...) NULL
-#endif
-
/* per-AG reservation */
DECLARE_EVENT_CLASS(xfs_ag_resv_class,
TP_PROTO(struct xfs_perag *pag, enum xfs_ag_resv_type resv,
diff --git a/fs/xfs/xfs_trans_extfree.c b/fs/xfs/xfs_trans_extfree.c
index d1b8833..ecb9a68 100644
--- a/fs/xfs/xfs_trans_extfree.c
+++ b/fs/xfs/xfs_trans_extfree.c
@@ -125,7 +125,8 @@ xfs_trans_free_extent(
struct xfs_extent *extp;
int error;

- error = xfs_free_extent(tp, start_block, ext_len, oinfo);
+ error = xfs_free_extent(tp, start_block, ext_len, oinfo,
+ XFS_AG_RESV_NONE);

/*
* Mark the transaction dirty, even on error. This ensures the