2018-06-06 10:42:14 +08:00
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// SPDX-License-Identifier: GPL-2.0+
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xfs: set up per-AG free space reservations
One unfortunate quirk of the reference count and reverse mapping
btrees -- they 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.
The transaction block reservation counters aren't sufficient here
because we have to have a reserve of blocks in every AG, not just
somewhere in the filesystem.
Therefore, create two per-AG block reservation pools. One feeds the
AGFL so that rmapbt expansion always succeeds, and the other feeds all
other metadata so that refcountbt expansion never fails.
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).
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-09-19 08:30:52 +08:00
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/*
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* Copyright (C) 2016 Oracle. All Rights Reserved.
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* Author: Darrick J. Wong <darrick.wong@oracle.com>
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*/
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#include "xfs.h"
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#include "xfs_fs.h"
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#include "xfs_shared.h"
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#include "xfs_format.h"
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#include "xfs_log_format.h"
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#include "xfs_trans_resv.h"
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#include "xfs_sb.h"
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#include "xfs_mount.h"
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#include "xfs_defer.h"
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#include "xfs_alloc.h"
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2017-11-01 03:04:49 +08:00
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#include "xfs_errortag.h"
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xfs: set up per-AG free space reservations
One unfortunate quirk of the reference count and reverse mapping
btrees -- they 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.
The transaction block reservation counters aren't sufficient here
because we have to have a reserve of blocks in every AG, not just
somewhere in the filesystem.
Therefore, create two per-AG block reservation pools. One feeds the
AGFL so that rmapbt expansion always succeeds, and the other feeds all
other metadata so that refcountbt expansion never fails.
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).
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-09-19 08:30:52 +08:00
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#include "xfs_error.h"
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#include "xfs_trace.h"
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#include "xfs_cksum.h"
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#include "xfs_trans.h"
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#include "xfs_bit.h"
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#include "xfs_bmap.h"
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#include "xfs_bmap_btree.h"
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#include "xfs_ag_resv.h"
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#include "xfs_trans_space.h"
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#include "xfs_rmap_btree.h"
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#include "xfs_btree.h"
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2016-10-04 00:11:44 +08:00
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#include "xfs_refcount_btree.h"
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2017-01-25 23:49:35 +08:00
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#include "xfs_ialloc_btree.h"
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xfs: set up per-AG free space reservations
One unfortunate quirk of the reference count and reverse mapping
btrees -- they 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.
The transaction block reservation counters aren't sufficient here
because we have to have a reserve of blocks in every AG, not just
somewhere in the filesystem.
Therefore, create two per-AG block reservation pools. One feeds the
AGFL so that rmapbt expansion always succeeds, and the other feeds all
other metadata so that refcountbt expansion never fails.
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).
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-09-19 08:30:52 +08:00
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/*
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* Per-AG Block Reservations
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*
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* For some kinds of allocation group metadata structures, it is advantageous
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* to reserve a small number of blocks in each AG so that future expansions of
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* that data structure do not encounter ENOSPC because errors during a btree
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* split cause the filesystem to go offline.
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*
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* Prior to the introduction of reflink, this wasn't an issue because the free
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* space btrees maintain a reserve of space (the AGFL) to handle any expansion
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* that may be necessary; and allocations of other metadata (inodes, BMBT,
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* dir/attr) aren't restricted to a single AG. However, with reflink it is
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* possible to allocate all the space in an AG, have subsequent reflink/CoW
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* activity expand the refcount btree, and discover that there's no space left
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* to handle that expansion. Since we can calculate the maximum size of the
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* refcount btree, we can reserve space for it and avoid ENOSPC.
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*
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* Handling per-AG reservations consists of three changes to the allocator's
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* behavior: First, because these reservations are always needed, we decrease
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* the ag_max_usable counter to reflect the size of the AG after the reserved
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* blocks are taken. Second, the reservations must be reflected in the
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* fdblocks count to maintain proper accounting. Third, each AG must maintain
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* its own reserved block counter so that we can calculate the amount of space
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* that must remain free to maintain the reservations. Fourth, the "remaining
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* reserved blocks" count must be used when calculating the length of the
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* longest free extent in an AG and to clamp maxlen in the per-AG allocation
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* functions. In other words, we maintain a virtual allocation via in-core
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* accounting tricks so that we don't have to clean up after a crash. :)
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*
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* Reserved blocks can be managed by passing one of the enum xfs_ag_resv_type
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* values via struct xfs_alloc_arg or directly to the xfs_free_extent
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* function. It might seem a little funny to maintain a reservoir of blocks
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* to feed another reservoir, but the AGFL only holds enough blocks to get
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* through the next transaction. The per-AG reservation is to ensure (we
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* hope) that each AG never runs out of blocks. Each data structure wanting
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* to use the reservation system should update ask/used in xfs_ag_resv_init.
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*/
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/*
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* Are we critically low on blocks? For now we'll define that as the number
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* of blocks we can get our hands on being less than 10% of what we reserved
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* or less than some arbitrary number (maximum btree height).
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*/
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bool
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xfs_ag_resv_critical(
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struct xfs_perag *pag,
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enum xfs_ag_resv_type type)
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{
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xfs_extlen_t avail;
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xfs_extlen_t orig;
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switch (type) {
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case XFS_AG_RESV_METADATA:
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2018-03-10 06:01:59 +08:00
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avail = pag->pagf_freeblks - pag->pag_rmapbt_resv.ar_reserved;
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xfs: set up per-AG free space reservations
One unfortunate quirk of the reference count and reverse mapping
btrees -- they 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.
The transaction block reservation counters aren't sufficient here
because we have to have a reserve of blocks in every AG, not just
somewhere in the filesystem.
Therefore, create two per-AG block reservation pools. One feeds the
AGFL so that rmapbt expansion always succeeds, and the other feeds all
other metadata so that refcountbt expansion never fails.
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).
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-09-19 08:30:52 +08:00
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orig = pag->pag_meta_resv.ar_asked;
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break;
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2018-03-10 06:01:59 +08:00
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case XFS_AG_RESV_RMAPBT:
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xfs: set up per-AG free space reservations
One unfortunate quirk of the reference count and reverse mapping
btrees -- they 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.
The transaction block reservation counters aren't sufficient here
because we have to have a reserve of blocks in every AG, not just
somewhere in the filesystem.
Therefore, create two per-AG block reservation pools. One feeds the
AGFL so that rmapbt expansion always succeeds, and the other feeds all
other metadata so that refcountbt expansion never fails.
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).
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-09-19 08:30:52 +08:00
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avail = pag->pagf_freeblks + pag->pagf_flcount -
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pag->pag_meta_resv.ar_reserved;
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2018-03-10 06:01:59 +08:00
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orig = pag->pag_rmapbt_resv.ar_asked;
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xfs: set up per-AG free space reservations
One unfortunate quirk of the reference count and reverse mapping
btrees -- they 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.
The transaction block reservation counters aren't sufficient here
because we have to have a reserve of blocks in every AG, not just
somewhere in the filesystem.
Therefore, create two per-AG block reservation pools. One feeds the
AGFL so that rmapbt expansion always succeeds, and the other feeds all
other metadata so that refcountbt expansion never fails.
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).
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-09-19 08:30:52 +08:00
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break;
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default:
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ASSERT(0);
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return false;
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}
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trace_xfs_ag_resv_critical(pag, type, avail);
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/* Critically low if less than 10% or max btree height remains. */
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2016-10-04 00:11:51 +08:00
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return XFS_TEST_ERROR(avail < orig / 10 || avail < XFS_BTREE_MAXLEVELS,
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2017-06-21 08:54:47 +08:00
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pag->pag_mount, XFS_ERRTAG_AG_RESV_CRITICAL);
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xfs: set up per-AG free space reservations
One unfortunate quirk of the reference count and reverse mapping
btrees -- they 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.
The transaction block reservation counters aren't sufficient here
because we have to have a reserve of blocks in every AG, not just
somewhere in the filesystem.
Therefore, create two per-AG block reservation pools. One feeds the
AGFL so that rmapbt expansion always succeeds, and the other feeds all
other metadata so that refcountbt expansion never fails.
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).
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-09-19 08:30:52 +08:00
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}
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/*
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* How many blocks are reserved but not used, and therefore must not be
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* allocated away?
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*/
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xfs_extlen_t
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xfs_ag_resv_needed(
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struct xfs_perag *pag,
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enum xfs_ag_resv_type type)
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{
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xfs_extlen_t len;
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2018-03-10 06:01:59 +08:00
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len = pag->pag_meta_resv.ar_reserved + pag->pag_rmapbt_resv.ar_reserved;
|
xfs: set up per-AG free space reservations
One unfortunate quirk of the reference count and reverse mapping
btrees -- they 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.
The transaction block reservation counters aren't sufficient here
because we have to have a reserve of blocks in every AG, not just
somewhere in the filesystem.
Therefore, create two per-AG block reservation pools. One feeds the
AGFL so that rmapbt expansion always succeeds, and the other feeds all
other metadata so that refcountbt expansion never fails.
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).
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-09-19 08:30:52 +08:00
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switch (type) {
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case XFS_AG_RESV_METADATA:
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2018-03-10 06:01:59 +08:00
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case XFS_AG_RESV_RMAPBT:
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xfs: set up per-AG free space reservations
One unfortunate quirk of the reference count and reverse mapping
btrees -- they 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.
The transaction block reservation counters aren't sufficient here
because we have to have a reserve of blocks in every AG, not just
somewhere in the filesystem.
Therefore, create two per-AG block reservation pools. One feeds the
AGFL so that rmapbt expansion always succeeds, and the other feeds all
other metadata so that refcountbt expansion never fails.
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).
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-09-19 08:30:52 +08:00
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len -= xfs_perag_resv(pag, type)->ar_reserved;
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break;
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case XFS_AG_RESV_NONE:
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/* empty */
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break;
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default:
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ASSERT(0);
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}
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trace_xfs_ag_resv_needed(pag, type, len);
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return len;
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}
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/* Clean out a reservation */
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static int
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__xfs_ag_resv_free(
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struct xfs_perag *pag,
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enum xfs_ag_resv_type type)
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{
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struct xfs_ag_resv *resv;
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xfs_extlen_t oldresv;
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int error;
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trace_xfs_ag_resv_free(pag, type, 0);
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resv = xfs_perag_resv(pag, type);
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2017-09-19 00:42:09 +08:00
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if (pag->pag_agno == 0)
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pag->pag_mount->m_ag_max_usable += resv->ar_asked;
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xfs: set up per-AG free space reservations
One unfortunate quirk of the reference count and reverse mapping
btrees -- they 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.
The transaction block reservation counters aren't sufficient here
because we have to have a reserve of blocks in every AG, not just
somewhere in the filesystem.
Therefore, create two per-AG block reservation pools. One feeds the
AGFL so that rmapbt expansion always succeeds, and the other feeds all
other metadata so that refcountbt expansion never fails.
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).
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-09-19 08:30:52 +08:00
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/*
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2018-03-10 06:01:59 +08:00
|
|
|
* 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.
|
xfs: set up per-AG free space reservations
One unfortunate quirk of the reference count and reverse mapping
btrees -- they 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.
The transaction block reservation counters aren't sufficient here
because we have to have a reserve of blocks in every AG, not just
somewhere in the filesystem.
Therefore, create two per-AG block reservation pools. One feeds the
AGFL so that rmapbt expansion always succeeds, and the other feeds all
other metadata so that refcountbt expansion never fails.
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).
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-09-19 08:30:52 +08:00
|
|
|
*/
|
2018-03-10 06:01:59 +08:00
|
|
|
if (type == XFS_AG_RESV_RMAPBT)
|
xfs: set up per-AG free space reservations
One unfortunate quirk of the reference count and reverse mapping
btrees -- they 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.
The transaction block reservation counters aren't sufficient here
because we have to have a reserve of blocks in every AG, not just
somewhere in the filesystem.
Therefore, create two per-AG block reservation pools. One feeds the
AGFL so that rmapbt expansion always succeeds, and the other feeds all
other metadata so that refcountbt expansion never fails.
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).
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-09-19 08:30:52 +08:00
|
|
|
oldresv = resv->ar_orig_reserved;
|
|
|
|
|
else
|
|
|
|
|
oldresv = resv->ar_reserved;
|
|
|
|
|
error = xfs_mod_fdblocks(pag->pag_mount, oldresv, true);
|
|
|
|
|
resv->ar_reserved = 0;
|
|
|
|
|
resv->ar_asked = 0;
|
2018-06-22 14:26:56 +08:00
|
|
|
resv->ar_orig_reserved = 0;
|
xfs: set up per-AG free space reservations
One unfortunate quirk of the reference count and reverse mapping
btrees -- they 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.
The transaction block reservation counters aren't sufficient here
because we have to have a reserve of blocks in every AG, not just
somewhere in the filesystem.
Therefore, create two per-AG block reservation pools. One feeds the
AGFL so that rmapbt expansion always succeeds, and the other feeds all
other metadata so that refcountbt expansion never fails.
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).
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-09-19 08:30:52 +08:00
|
|
|
|
|
|
|
|
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;
|
|
|
|
|
int err2;
|
|
|
|
|
|
2018-03-10 06:01:59 +08:00
|
|
|
error = __xfs_ag_resv_free(pag, XFS_AG_RESV_RMAPBT);
|
xfs: set up per-AG free space reservations
One unfortunate quirk of the reference count and reverse mapping
btrees -- they 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.
The transaction block reservation counters aren't sufficient here
because we have to have a reserve of blocks in every AG, not just
somewhere in the filesystem.
Therefore, create two per-AG block reservation pools. One feeds the
AGFL so that rmapbt expansion always succeeds, and the other feeds all
other metadata so that refcountbt expansion never fails.
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).
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-09-19 08:30:52 +08:00
|
|
|
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;
|
2018-06-22 14:26:56 +08:00
|
|
|
xfs_extlen_t hidden_space;
|
xfs: set up per-AG free space reservations
One unfortunate quirk of the reference count and reverse mapping
btrees -- they 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.
The transaction block reservation counters aren't sufficient here
because we have to have a reserve of blocks in every AG, not just
somewhere in the filesystem.
Therefore, create two per-AG block reservation pools. One feeds the
AGFL so that rmapbt expansion always succeeds, and the other feeds all
other metadata so that refcountbt expansion never fails.
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).
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-09-19 08:30:52 +08:00
|
|
|
|
|
|
|
|
if (used > ask)
|
|
|
|
|
ask = used;
|
|
|
|
|
|
2018-06-22 14:26:56 +08:00
|
|
|
switch (type) {
|
|
|
|
|
case XFS_AG_RESV_RMAPBT:
|
|
|
|
|
/*
|
|
|
|
|
* Space taken by the rmapbt is not subtracted from fdblocks
|
|
|
|
|
* because the rmapbt lives in the free space. Here we must
|
|
|
|
|
* subtract the entire reservation from fdblocks so that we
|
|
|
|
|
* always have blocks available for rmapbt expansion.
|
|
|
|
|
*/
|
|
|
|
|
hidden_space = ask;
|
|
|
|
|
break;
|
|
|
|
|
case XFS_AG_RESV_METADATA:
|
|
|
|
|
/*
|
|
|
|
|
* Space taken by all other metadata btrees are accounted
|
|
|
|
|
* on-disk as used space. We therefore only hide the space
|
|
|
|
|
* that is reserved but not used by the trees.
|
|
|
|
|
*/
|
|
|
|
|
hidden_space = ask - used;
|
|
|
|
|
break;
|
|
|
|
|
default:
|
|
|
|
|
ASSERT(0);
|
|
|
|
|
return -EINVAL;
|
|
|
|
|
}
|
|
|
|
|
error = xfs_mod_fdblocks(mp, -(int64_t)hidden_space, true);
|
2017-01-25 23:49:34 +08:00
|
|
|
if (error) {
|
xfs: set up per-AG free space reservations
One unfortunate quirk of the reference count and reverse mapping
btrees -- they 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.
The transaction block reservation counters aren't sufficient here
because we have to have a reserve of blocks in every AG, not just
somewhere in the filesystem.
Therefore, create two per-AG block reservation pools. One feeds the
AGFL so that rmapbt expansion always succeeds, and the other feeds all
other metadata so that refcountbt expansion never fails.
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).
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-09-19 08:30:52 +08:00
|
|
|
trace_xfs_ag_resv_init_error(pag->pag_mount, pag->pag_agno,
|
|
|
|
|
error, _RET_IP_);
|
2017-01-25 23:49:35 +08:00
|
|
|
xfs_warn(mp,
|
|
|
|
|
"Per-AG reservation for AG %u failed. Filesystem may run out of space.",
|
|
|
|
|
pag->pag_agno);
|
2017-01-25 23:49:34 +08:00
|
|
|
return error;
|
|
|
|
|
}
|
xfs: set up per-AG free space reservations
One unfortunate quirk of the reference count and reverse mapping
btrees -- they 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.
The transaction block reservation counters aren't sufficient here
because we have to have a reserve of blocks in every AG, not just
somewhere in the filesystem.
Therefore, create two per-AG block reservation pools. One feeds the
AGFL so that rmapbt expansion always succeeds, and the other feeds all
other metadata so that refcountbt expansion never fails.
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).
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-09-19 08:30:52 +08:00
|
|
|
|
2017-09-19 00:42:09 +08:00
|
|
|
/*
|
|
|
|
|
* Reduce the maximum per-AG allocation length by however much we're
|
|
|
|
|
* trying to reserve for an AG. Since this is a filesystem-wide
|
|
|
|
|
* counter, we only make the adjustment for AG 0. This assumes that
|
|
|
|
|
* there aren't any AGs hungrier for per-AG reservation than AG 0.
|
|
|
|
|
*/
|
|
|
|
|
if (pag->pag_agno == 0)
|
|
|
|
|
mp->m_ag_max_usable -= ask;
|
2017-01-25 23:49:34 +08:00
|
|
|
|
|
|
|
|
resv = xfs_perag_resv(pag, type);
|
|
|
|
|
resv->ar_asked = ask;
|
2018-06-22 14:26:56 +08:00
|
|
|
resv->ar_orig_reserved = hidden_space;
|
|
|
|
|
resv->ar_reserved = ask - used;
|
2017-01-25 23:49:34 +08:00
|
|
|
|
|
|
|
|
trace_xfs_ag_resv_init(pag, type, ask);
|
|
|
|
|
return 0;
|
xfs: set up per-AG free space reservations
One unfortunate quirk of the reference count and reverse mapping
btrees -- they 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.
The transaction block reservation counters aren't sufficient here
because we have to have a reserve of blocks in every AG, not just
somewhere in the filesystem.
Therefore, create two per-AG block reservation pools. One feeds the
AGFL so that rmapbt expansion always succeeds, and the other feeds all
other metadata so that refcountbt expansion never fails.
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).
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-09-19 08:30:52 +08:00
|
|
|
}
|
|
|
|
|
|
|
|
|
|
/* Create a per-AG block reservation. */
|
|
|
|
|
int
|
|
|
|
|
xfs_ag_resv_init(
|
2018-07-30 13:37:08 +08:00
|
|
|
struct xfs_perag *pag,
|
|
|
|
|
struct xfs_trans *tp)
|
xfs: set up per-AG free space reservations
One unfortunate quirk of the reference count and reverse mapping
btrees -- they 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.
The transaction block reservation counters aren't sufficient here
because we have to have a reserve of blocks in every AG, not just
somewhere in the filesystem.
Therefore, create two per-AG block reservation pools. One feeds the
AGFL so that rmapbt expansion always succeeds, and the other feeds all
other metadata so that refcountbt expansion never fails.
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).
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-09-19 08:30:52 +08:00
|
|
|
{
|
2017-01-25 23:49:35 +08:00
|
|
|
struct xfs_mount *mp = pag->pag_mount;
|
|
|
|
|
xfs_agnumber_t agno = pag->pag_agno;
|
xfs: set up per-AG free space reservations
One unfortunate quirk of the reference count and reverse mapping
btrees -- they 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.
The transaction block reservation counters aren't sufficient here
because we have to have a reserve of blocks in every AG, not just
somewhere in the filesystem.
Therefore, create two per-AG block reservation pools. One feeds the
AGFL so that rmapbt expansion always succeeds, and the other feeds all
other metadata so that refcountbt expansion never fails.
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).
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-09-19 08:30:52 +08:00
|
|
|
xfs_extlen_t ask;
|
|
|
|
|
xfs_extlen_t used;
|
|
|
|
|
int error = 0;
|
|
|
|
|
|
|
|
|
|
/* Create the metadata reservation. */
|
|
|
|
|
if (pag->pag_meta_resv.ar_asked == 0) {
|
|
|
|
|
ask = used = 0;
|
|
|
|
|
|
2018-07-30 13:37:08 +08:00
|
|
|
error = xfs_refcountbt_calc_reserves(mp, tp, agno, &ask, &used);
|
2016-10-04 00:11:44 +08:00
|
|
|
if (error)
|
|
|
|
|
goto out;
|
|
|
|
|
|
2018-07-30 13:37:08 +08:00
|
|
|
error = xfs_finobt_calc_reserves(mp, tp, agno, &ask, &used);
|
xfs: set up per-AG free space reservations
One unfortunate quirk of the reference count and reverse mapping
btrees -- they 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.
The transaction block reservation counters aren't sufficient here
because we have to have a reserve of blocks in every AG, not just
somewhere in the filesystem.
Therefore, create two per-AG block reservation pools. One feeds the
AGFL so that rmapbt expansion always succeeds, and the other feeds all
other metadata so that refcountbt expansion never fails.
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).
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-09-19 08:30:52 +08:00
|
|
|
if (error)
|
|
|
|
|
goto out;
|
2017-01-25 23:49:35 +08:00
|
|
|
|
|
|
|
|
error = __xfs_ag_resv_init(pag, XFS_AG_RESV_METADATA,
|
|
|
|
|
ask, used);
|
|
|
|
|
if (error) {
|
|
|
|
|
/*
|
|
|
|
|
* Because we didn't have per-AG reservations when the
|
|
|
|
|
* finobt feature was added we might not be able to
|
|
|
|
|
* reserve all needed blocks. Warn and fall back to the
|
|
|
|
|
* old and potentially buggy code in that case, but
|
|
|
|
|
* ensure we do have the reservation for the refcountbt.
|
|
|
|
|
*/
|
|
|
|
|
ask = used = 0;
|
|
|
|
|
|
|
|
|
|
mp->m_inotbt_nores = true;
|
|
|
|
|
|
2018-07-30 13:37:08 +08:00
|
|
|
error = xfs_refcountbt_calc_reserves(mp, tp, agno, &ask,
|
2017-01-25 23:49:35 +08:00
|
|
|
&used);
|
|
|
|
|
if (error)
|
|
|
|
|
goto out;
|
|
|
|
|
|
|
|
|
|
error = __xfs_ag_resv_init(pag, XFS_AG_RESV_METADATA,
|
|
|
|
|
ask, used);
|
|
|
|
|
if (error)
|
|
|
|
|
goto out;
|
|
|
|
|
}
|
xfs: set up per-AG free space reservations
One unfortunate quirk of the reference count and reverse mapping
btrees -- they 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.
The transaction block reservation counters aren't sufficient here
because we have to have a reserve of blocks in every AG, not just
somewhere in the filesystem.
Therefore, create two per-AG block reservation pools. One feeds the
AGFL so that rmapbt expansion always succeeds, and the other feeds all
other metadata so that refcountbt expansion never fails.
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).
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-09-19 08:30:52 +08:00
|
|
|
}
|
|
|
|
|
|
2018-03-10 06:01:59 +08:00
|
|
|
/* Create the RMAPBT metadata reservation */
|
|
|
|
|
if (pag->pag_rmapbt_resv.ar_asked == 0) {
|
xfs: set up per-AG free space reservations
One unfortunate quirk of the reference count and reverse mapping
btrees -- they 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.
The transaction block reservation counters aren't sufficient here
because we have to have a reserve of blocks in every AG, not just
somewhere in the filesystem.
Therefore, create two per-AG block reservation pools. One feeds the
AGFL so that rmapbt expansion always succeeds, and the other feeds all
other metadata so that refcountbt expansion never fails.
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).
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-09-19 08:30:52 +08:00
|
|
|
ask = used = 0;
|
|
|
|
|
|
2018-07-30 13:37:08 +08:00
|
|
|
error = xfs_rmapbt_calc_reserves(mp, tp, agno, &ask, &used);
|
2016-10-04 00:11:44 +08:00
|
|
|
if (error)
|
|
|
|
|
goto out;
|
|
|
|
|
|
2018-03-10 06:01:59 +08:00
|
|
|
error = __xfs_ag_resv_init(pag, XFS_AG_RESV_RMAPBT, ask, used);
|
xfs: set up per-AG free space reservations
One unfortunate quirk of the reference count and reverse mapping
btrees -- they 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.
The transaction block reservation counters aren't sufficient here
because we have to have a reserve of blocks in every AG, not just
somewhere in the filesystem.
Therefore, create two per-AG block reservation pools. One feeds the
AGFL so that rmapbt expansion always succeeds, and the other feeds all
other metadata so that refcountbt expansion never fails.
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).
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-09-19 08:30:52 +08:00
|
|
|
if (error)
|
|
|
|
|
goto out;
|
|
|
|
|
}
|
|
|
|
|
|
2017-01-25 23:49:35 +08:00
|
|
|
#ifdef DEBUG
|
|
|
|
|
/* need to read in the AGF for the ASSERT below to work */
|
2018-07-30 13:37:08 +08:00
|
|
|
error = xfs_alloc_pagf_init(pag->pag_mount, tp, pag->pag_agno, 0);
|
2017-01-25 23:49:35 +08:00
|
|
|
if (error)
|
|
|
|
|
return error;
|
|
|
|
|
|
2017-01-04 10:39:33 +08:00
|
|
|
ASSERT(xfs_perag_resv(pag, XFS_AG_RESV_METADATA)->ar_reserved +
|
2018-03-10 06:01:59 +08:00
|
|
|
xfs_perag_resv(pag, XFS_AG_RESV_RMAPBT)->ar_reserved <=
|
2017-01-04 10:39:33 +08:00
|
|
|
pag->pagf_freeblks + pag->pagf_flcount);
|
2017-01-25 23:49:35 +08:00
|
|
|
#endif
|
xfs: set up per-AG free space reservations
One unfortunate quirk of the reference count and reverse mapping
btrees -- they 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.
The transaction block reservation counters aren't sufficient here
because we have to have a reserve of blocks in every AG, not just
somewhere in the filesystem.
Therefore, create two per-AG block reservation pools. One feeds the
AGFL so that rmapbt expansion always succeeds, and the other feeds all
other metadata so that refcountbt expansion never fails.
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).
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-09-19 08:30:52 +08:00
|
|
|
out:
|
|
|
|
|
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 len;
|
|
|
|
|
uint field;
|
|
|
|
|
|
|
|
|
|
trace_xfs_ag_resv_alloc_extent(pag, type, args->len);
|
|
|
|
|
|
|
|
|
|
switch (type) {
|
2018-03-10 06:02:32 +08:00
|
|
|
case XFS_AG_RESV_AGFL:
|
|
|
|
|
return;
|
xfs: set up per-AG free space reservations
One unfortunate quirk of the reference count and reverse mapping
btrees -- they 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.
The transaction block reservation counters aren't sufficient here
because we have to have a reserve of blocks in every AG, not just
somewhere in the filesystem.
Therefore, create two per-AG block reservation pools. One feeds the
AGFL so that rmapbt expansion always succeeds, and the other feeds all
other metadata so that refcountbt expansion never fails.
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).
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-09-19 08:30:52 +08:00
|
|
|
case XFS_AG_RESV_METADATA:
|
2018-03-10 06:01:59 +08:00
|
|
|
case XFS_AG_RESV_RMAPBT:
|
xfs: set up per-AG free space reservations
One unfortunate quirk of the reference count and reverse mapping
btrees -- they 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.
The transaction block reservation counters aren't sufficient here
because we have to have a reserve of blocks in every AG, not just
somewhere in the filesystem.
Therefore, create two per-AG block reservation pools. One feeds the
AGFL so that rmapbt expansion always succeeds, and the other feeds all
other metadata so that refcountbt expansion never fails.
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).
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-09-19 08:30:52 +08:00
|
|
|
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;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
len = min_t(xfs_extlen_t, args->len, resv->ar_reserved);
|
|
|
|
|
resv->ar_reserved -= len;
|
2018-03-10 06:01:59 +08:00
|
|
|
if (type == XFS_AG_RESV_RMAPBT)
|
xfs: set up per-AG free space reservations
One unfortunate quirk of the reference count and reverse mapping
btrees -- they 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.
The transaction block reservation counters aren't sufficient here
because we have to have a reserve of blocks in every AG, not just
somewhere in the filesystem.
Therefore, create two per-AG block reservation pools. One feeds the
AGFL so that rmapbt expansion always succeeds, and the other feeds all
other metadata so that refcountbt expansion never fails.
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).
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-09-19 08:30:52 +08:00
|
|
|
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);
|
|
|
|
|
/* ...but non-reserved blocks need in-core and on-disk updates. */
|
|
|
|
|
if (args->len > len)
|
|
|
|
|
xfs_trans_mod_sb(args->tp, XFS_TRANS_SB_FDBLOCKS,
|
|
|
|
|
-((int64_t)args->len - 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) {
|
2018-03-10 06:02:32 +08:00
|
|
|
case XFS_AG_RESV_AGFL:
|
|
|
|
|
return;
|
xfs: set up per-AG free space reservations
One unfortunate quirk of the reference count and reverse mapping
btrees -- they 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.
The transaction block reservation counters aren't sufficient here
because we have to have a reserve of blocks in every AG, not just
somewhere in the filesystem.
Therefore, create two per-AG block reservation pools. One feeds the
AGFL so that rmapbt expansion always succeeds, and the other feeds all
other metadata so that refcountbt expansion never fails.
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).
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-09-19 08:30:52 +08:00
|
|
|
case XFS_AG_RESV_METADATA:
|
2018-03-10 06:01:59 +08:00
|
|
|
case XFS_AG_RESV_RMAPBT:
|
xfs: set up per-AG free space reservations
One unfortunate quirk of the reference count and reverse mapping
btrees -- they 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.
The transaction block reservation counters aren't sufficient here
because we have to have a reserve of blocks in every AG, not just
somewhere in the filesystem.
Therefore, create two per-AG block reservation pools. One feeds the
AGFL so that rmapbt expansion always succeeds, and the other feeds all
other metadata so that refcountbt expansion never fails.
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).
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-09-19 08:30:52 +08:00
|
|
|
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;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
leftover = min_t(xfs_extlen_t, len, resv->ar_asked - resv->ar_reserved);
|
|
|
|
|
resv->ar_reserved += leftover;
|
2018-03-10 06:01:59 +08:00
|
|
|
if (type == XFS_AG_RESV_RMAPBT)
|
xfs: set up per-AG free space reservations
One unfortunate quirk of the reference count and reverse mapping
btrees -- they 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.
The transaction block reservation counters aren't sufficient here
because we have to have a reserve of blocks in every AG, not just
somewhere in the filesystem.
Therefore, create two per-AG block reservation pools. One feeds the
AGFL so that rmapbt expansion always succeeds, and the other feeds all
other metadata so that refcountbt expansion never fails.
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).
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-09-19 08:30:52 +08:00
|
|
|
return;
|
|
|
|
|
/* Freeing into the reserved pool only requires on-disk update... */
|
|
|
|
|
xfs_trans_mod_sb(tp, XFS_TRANS_SB_RES_FDBLOCKS, len);
|
|
|
|
|
/* ...but freeing beyond that requires in-core and on-disk update. */
|
|
|
|
|
if (len > leftover)
|
|
|
|
|
xfs_trans_mod_sb(tp, XFS_TRANS_SB_FDBLOCKS, len - leftover);
|
|
|
|
|
}
|