![Darrick J. Wong](/assets/img/avatar_default.png)
commit 3ecb3ac7b9
upstream.
If a malicious user corrupts the refcount btree to cause a cycle between
different levels of the tree, the next mount attempt will deadlock in
the CoW recovery routine while grabbing buffer locks. We can use the
ability to re-grab a buffer that was previous locked to a transaction to
avoid deadlocks, so do that here.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
1718 lines
47 KiB
C
1718 lines
47 KiB
C
/*
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* Copyright (C) 2016 Oracle. All Rights Reserved.
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*
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* Author: Darrick J. Wong <darrick.wong@oracle.com>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it would be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.
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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_btree.h"
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#include "xfs_bmap.h"
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#include "xfs_refcount_btree.h"
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#include "xfs_alloc.h"
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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_refcount.h"
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#include "xfs_rmap.h"
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/* Allowable refcount adjustment amounts. */
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enum xfs_refc_adjust_op {
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XFS_REFCOUNT_ADJUST_INCREASE = 1,
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XFS_REFCOUNT_ADJUST_DECREASE = -1,
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XFS_REFCOUNT_ADJUST_COW_ALLOC = 0,
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XFS_REFCOUNT_ADJUST_COW_FREE = -1,
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};
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STATIC int __xfs_refcount_cow_alloc(struct xfs_btree_cur *rcur,
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xfs_agblock_t agbno, xfs_extlen_t aglen,
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struct xfs_defer_ops *dfops);
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STATIC int __xfs_refcount_cow_free(struct xfs_btree_cur *rcur,
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xfs_agblock_t agbno, xfs_extlen_t aglen,
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struct xfs_defer_ops *dfops);
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/*
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* Look up the first record less than or equal to [bno, len] in the btree
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* given by cur.
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*/
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int
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xfs_refcount_lookup_le(
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struct xfs_btree_cur *cur,
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xfs_agblock_t bno,
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int *stat)
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{
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trace_xfs_refcount_lookup(cur->bc_mp, cur->bc_private.a.agno, bno,
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XFS_LOOKUP_LE);
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cur->bc_rec.rc.rc_startblock = bno;
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cur->bc_rec.rc.rc_blockcount = 0;
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return xfs_btree_lookup(cur, XFS_LOOKUP_LE, stat);
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}
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/*
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* Look up the first record greater than or equal to [bno, len] in the btree
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* given by cur.
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*/
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int
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xfs_refcount_lookup_ge(
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struct xfs_btree_cur *cur,
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xfs_agblock_t bno,
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int *stat)
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{
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trace_xfs_refcount_lookup(cur->bc_mp, cur->bc_private.a.agno, bno,
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XFS_LOOKUP_GE);
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cur->bc_rec.rc.rc_startblock = bno;
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cur->bc_rec.rc.rc_blockcount = 0;
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return xfs_btree_lookup(cur, XFS_LOOKUP_GE, stat);
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}
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/* Convert on-disk record to in-core format. */
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static inline void
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xfs_refcount_btrec_to_irec(
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union xfs_btree_rec *rec,
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struct xfs_refcount_irec *irec)
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{
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irec->rc_startblock = be32_to_cpu(rec->refc.rc_startblock);
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irec->rc_blockcount = be32_to_cpu(rec->refc.rc_blockcount);
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irec->rc_refcount = be32_to_cpu(rec->refc.rc_refcount);
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}
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/*
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* Get the data from the pointed-to record.
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*/
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int
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xfs_refcount_get_rec(
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struct xfs_btree_cur *cur,
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struct xfs_refcount_irec *irec,
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int *stat)
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{
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union xfs_btree_rec *rec;
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int error;
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error = xfs_btree_get_rec(cur, &rec, stat);
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if (!error && *stat == 1) {
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xfs_refcount_btrec_to_irec(rec, irec);
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trace_xfs_refcount_get(cur->bc_mp, cur->bc_private.a.agno,
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irec);
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}
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return error;
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}
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/*
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* Update the record referred to by cur to the value given
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* by [bno, len, refcount].
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* This either works (return 0) or gets an EFSCORRUPTED error.
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*/
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STATIC int
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xfs_refcount_update(
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struct xfs_btree_cur *cur,
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struct xfs_refcount_irec *irec)
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{
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union xfs_btree_rec rec;
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int error;
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trace_xfs_refcount_update(cur->bc_mp, cur->bc_private.a.agno, irec);
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rec.refc.rc_startblock = cpu_to_be32(irec->rc_startblock);
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rec.refc.rc_blockcount = cpu_to_be32(irec->rc_blockcount);
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rec.refc.rc_refcount = cpu_to_be32(irec->rc_refcount);
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error = xfs_btree_update(cur, &rec);
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if (error)
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trace_xfs_refcount_update_error(cur->bc_mp,
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cur->bc_private.a.agno, error, _RET_IP_);
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return error;
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}
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/*
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* Insert the record referred to by cur to the value given
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* by [bno, len, refcount].
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* This either works (return 0) or gets an EFSCORRUPTED error.
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*/
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STATIC int
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xfs_refcount_insert(
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struct xfs_btree_cur *cur,
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struct xfs_refcount_irec *irec,
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int *i)
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{
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int error;
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trace_xfs_refcount_insert(cur->bc_mp, cur->bc_private.a.agno, irec);
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cur->bc_rec.rc.rc_startblock = irec->rc_startblock;
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cur->bc_rec.rc.rc_blockcount = irec->rc_blockcount;
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cur->bc_rec.rc.rc_refcount = irec->rc_refcount;
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error = xfs_btree_insert(cur, i);
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XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, *i == 1, out_error);
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out_error:
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if (error)
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trace_xfs_refcount_insert_error(cur->bc_mp,
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cur->bc_private.a.agno, error, _RET_IP_);
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return error;
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}
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/*
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* Remove the record referred to by cur, then set the pointer to the spot
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* where the record could be re-inserted, in case we want to increment or
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* decrement the cursor.
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* This either works (return 0) or gets an EFSCORRUPTED error.
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*/
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STATIC int
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xfs_refcount_delete(
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struct xfs_btree_cur *cur,
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int *i)
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{
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struct xfs_refcount_irec irec;
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int found_rec;
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int error;
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error = xfs_refcount_get_rec(cur, &irec, &found_rec);
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if (error)
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goto out_error;
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XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, found_rec == 1, out_error);
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trace_xfs_refcount_delete(cur->bc_mp, cur->bc_private.a.agno, &irec);
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error = xfs_btree_delete(cur, i);
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XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, *i == 1, out_error);
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if (error)
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goto out_error;
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error = xfs_refcount_lookup_ge(cur, irec.rc_startblock, &found_rec);
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out_error:
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if (error)
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trace_xfs_refcount_delete_error(cur->bc_mp,
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cur->bc_private.a.agno, error, _RET_IP_);
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return error;
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}
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/*
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* Adjusting the Reference Count
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*
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* As stated elsewhere, the reference count btree (refcbt) stores
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* >1 reference counts for extents of physical blocks. In this
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* operation, we're either raising or lowering the reference count of
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* some subrange stored in the tree:
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*
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* <------ adjustment range ------>
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* ----+ +---+-----+ +--+--------+---------
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* 2 | | 3 | 4 | |17| 55 | 10
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* ----+ +---+-----+ +--+--------+---------
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* X axis is physical blocks number;
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* reference counts are the numbers inside the rectangles
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*
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* The first thing we need to do is to ensure that there are no
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* refcount extents crossing either boundary of the range to be
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* adjusted. For any extent that does cross a boundary, split it into
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* two extents so that we can increment the refcount of one of the
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* pieces later:
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*
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* <------ adjustment range ------>
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* ----+ +---+-----+ +--+--------+----+----
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* 2 | | 3 | 2 | |17| 55 | 10 | 10
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* ----+ +---+-----+ +--+--------+----+----
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*
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* For this next step, let's assume that all the physical blocks in
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* the adjustment range are mapped to a file and are therefore in use
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* at least once. Therefore, we can infer that any gap in the
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* refcount tree within the adjustment range represents a physical
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* extent with refcount == 1:
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*
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* <------ adjustment range ------>
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* ----+---+---+-----+-+--+--------+----+----
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* 2 |"1"| 3 | 2 |1|17| 55 | 10 | 10
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* ----+---+---+-----+-+--+--------+----+----
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* ^
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*
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* For each extent that falls within the interval range, figure out
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* which extent is to the left or the right of that extent. Now we
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* have a left, current, and right extent. If the new reference count
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* of the center extent enables us to merge left, center, and right
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* into one record covering all three, do so. If the center extent is
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* at the left end of the range, abuts the left extent, and its new
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* reference count matches the left extent's record, then merge them.
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* If the center extent is at the right end of the range, abuts the
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* right extent, and the reference counts match, merge those. In the
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* example, we can left merge (assuming an increment operation):
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*
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* <------ adjustment range ------>
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* --------+---+-----+-+--+--------+----+----
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* 2 | 3 | 2 |1|17| 55 | 10 | 10
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* --------+---+-----+-+--+--------+----+----
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* ^
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*
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* For all other extents within the range, adjust the reference count
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* or delete it if the refcount falls below 2. If we were
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* incrementing, the end result looks like this:
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*
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* <------ adjustment range ------>
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* --------+---+-----+-+--+--------+----+----
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* 2 | 4 | 3 |2|18| 56 | 11 | 10
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* --------+---+-----+-+--+--------+----+----
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*
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* The result of a decrement operation looks as such:
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*
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* <------ adjustment range ------>
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* ----+ +---+ +--+--------+----+----
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* 2 | | 2 | |16| 54 | 9 | 10
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* ----+ +---+ +--+--------+----+----
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* DDDD 111111DD
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*
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* The blocks marked "D" are freed; the blocks marked "1" are only
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* referenced once and therefore the record is removed from the
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* refcount btree.
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*/
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/* Next block after this extent. */
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static inline xfs_agblock_t
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xfs_refc_next(
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struct xfs_refcount_irec *rc)
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{
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return rc->rc_startblock + rc->rc_blockcount;
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}
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/*
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* Split a refcount extent that crosses agbno.
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*/
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STATIC int
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xfs_refcount_split_extent(
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struct xfs_btree_cur *cur,
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xfs_agblock_t agbno,
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bool *shape_changed)
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{
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struct xfs_refcount_irec rcext, tmp;
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int found_rec;
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int error;
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*shape_changed = false;
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error = xfs_refcount_lookup_le(cur, agbno, &found_rec);
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if (error)
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goto out_error;
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if (!found_rec)
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return 0;
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error = xfs_refcount_get_rec(cur, &rcext, &found_rec);
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if (error)
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goto out_error;
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XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, found_rec == 1, out_error);
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if (rcext.rc_startblock == agbno || xfs_refc_next(&rcext) <= agbno)
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return 0;
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*shape_changed = true;
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trace_xfs_refcount_split_extent(cur->bc_mp, cur->bc_private.a.agno,
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&rcext, agbno);
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/* Establish the right extent. */
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tmp = rcext;
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tmp.rc_startblock = agbno;
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tmp.rc_blockcount -= (agbno - rcext.rc_startblock);
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error = xfs_refcount_update(cur, &tmp);
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if (error)
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goto out_error;
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/* Insert the left extent. */
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tmp = rcext;
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tmp.rc_blockcount = agbno - rcext.rc_startblock;
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error = xfs_refcount_insert(cur, &tmp, &found_rec);
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if (error)
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goto out_error;
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XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, found_rec == 1, out_error);
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return error;
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out_error:
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trace_xfs_refcount_split_extent_error(cur->bc_mp,
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cur->bc_private.a.agno, error, _RET_IP_);
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return error;
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}
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/*
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* Merge the left, center, and right extents.
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*/
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STATIC int
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xfs_refcount_merge_center_extents(
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struct xfs_btree_cur *cur,
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struct xfs_refcount_irec *left,
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struct xfs_refcount_irec *center,
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struct xfs_refcount_irec *right,
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unsigned long long extlen,
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xfs_agblock_t *agbno,
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xfs_extlen_t *aglen)
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{
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int error;
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int found_rec;
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trace_xfs_refcount_merge_center_extents(cur->bc_mp,
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cur->bc_private.a.agno, left, center, right);
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/*
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* Make sure the center and right extents are not in the btree.
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* If the center extent was synthesized, the first delete call
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* removes the right extent and we skip the second deletion.
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* If center and right were in the btree, then the first delete
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* call removes the center and the second one removes the right
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* extent.
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*/
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error = xfs_refcount_lookup_ge(cur, center->rc_startblock,
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&found_rec);
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if (error)
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goto out_error;
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XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, found_rec == 1, out_error);
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error = xfs_refcount_delete(cur, &found_rec);
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if (error)
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goto out_error;
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XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, found_rec == 1, out_error);
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|
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if (center->rc_refcount > 1) {
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error = xfs_refcount_delete(cur, &found_rec);
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if (error)
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goto out_error;
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XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, found_rec == 1,
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out_error);
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}
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/* Enlarge the left extent. */
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error = xfs_refcount_lookup_le(cur, left->rc_startblock,
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&found_rec);
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if (error)
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goto out_error;
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XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, found_rec == 1, out_error);
|
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|
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left->rc_blockcount = extlen;
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error = xfs_refcount_update(cur, left);
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if (error)
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goto out_error;
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*aglen = 0;
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return error;
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|
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out_error:
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trace_xfs_refcount_merge_center_extents_error(cur->bc_mp,
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cur->bc_private.a.agno, error, _RET_IP_);
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return error;
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}
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|
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/*
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* Merge with the left extent.
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*/
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STATIC int
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xfs_refcount_merge_left_extent(
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struct xfs_btree_cur *cur,
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struct xfs_refcount_irec *left,
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struct xfs_refcount_irec *cleft,
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xfs_agblock_t *agbno,
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xfs_extlen_t *aglen)
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{
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int error;
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int found_rec;
|
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|
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trace_xfs_refcount_merge_left_extent(cur->bc_mp,
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cur->bc_private.a.agno, left, cleft);
|
|
|
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/* If the extent at agbno (cleft) wasn't synthesized, remove it. */
|
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if (cleft->rc_refcount > 1) {
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error = xfs_refcount_lookup_le(cur, cleft->rc_startblock,
|
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&found_rec);
|
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if (error)
|
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goto out_error;
|
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XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, found_rec == 1,
|
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out_error);
|
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|
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error = xfs_refcount_delete(cur, &found_rec);
|
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if (error)
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goto out_error;
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XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, found_rec == 1,
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out_error);
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}
|
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|
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/* Enlarge the left extent. */
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error = xfs_refcount_lookup_le(cur, left->rc_startblock,
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&found_rec);
|
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if (error)
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goto out_error;
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XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, found_rec == 1, out_error);
|
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|
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left->rc_blockcount += cleft->rc_blockcount;
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error = xfs_refcount_update(cur, left);
|
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if (error)
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goto out_error;
|
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|
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*agbno += cleft->rc_blockcount;
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*aglen -= cleft->rc_blockcount;
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return error;
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|
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out_error:
|
|
trace_xfs_refcount_merge_left_extent_error(cur->bc_mp,
|
|
cur->bc_private.a.agno, error, _RET_IP_);
|
|
return error;
|
|
}
|
|
|
|
/*
|
|
* Merge with the right extent.
|
|
*/
|
|
STATIC int
|
|
xfs_refcount_merge_right_extent(
|
|
struct xfs_btree_cur *cur,
|
|
struct xfs_refcount_irec *right,
|
|
struct xfs_refcount_irec *cright,
|
|
xfs_agblock_t *agbno,
|
|
xfs_extlen_t *aglen)
|
|
{
|
|
int error;
|
|
int found_rec;
|
|
|
|
trace_xfs_refcount_merge_right_extent(cur->bc_mp,
|
|
cur->bc_private.a.agno, cright, right);
|
|
|
|
/*
|
|
* If the extent ending at agbno+aglen (cright) wasn't synthesized,
|
|
* remove it.
|
|
*/
|
|
if (cright->rc_refcount > 1) {
|
|
error = xfs_refcount_lookup_le(cur, cright->rc_startblock,
|
|
&found_rec);
|
|
if (error)
|
|
goto out_error;
|
|
XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, found_rec == 1,
|
|
out_error);
|
|
|
|
error = xfs_refcount_delete(cur, &found_rec);
|
|
if (error)
|
|
goto out_error;
|
|
XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, found_rec == 1,
|
|
out_error);
|
|
}
|
|
|
|
/* Enlarge the right extent. */
|
|
error = xfs_refcount_lookup_le(cur, right->rc_startblock,
|
|
&found_rec);
|
|
if (error)
|
|
goto out_error;
|
|
XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, found_rec == 1, out_error);
|
|
|
|
right->rc_startblock -= cright->rc_blockcount;
|
|
right->rc_blockcount += cright->rc_blockcount;
|
|
error = xfs_refcount_update(cur, right);
|
|
if (error)
|
|
goto out_error;
|
|
|
|
*aglen -= cright->rc_blockcount;
|
|
return error;
|
|
|
|
out_error:
|
|
trace_xfs_refcount_merge_right_extent_error(cur->bc_mp,
|
|
cur->bc_private.a.agno, error, _RET_IP_);
|
|
return error;
|
|
}
|
|
|
|
#define XFS_FIND_RCEXT_SHARED 1
|
|
#define XFS_FIND_RCEXT_COW 2
|
|
/*
|
|
* Find the left extent and the one after it (cleft). This function assumes
|
|
* that we've already split any extent crossing agbno.
|
|
*/
|
|
STATIC int
|
|
xfs_refcount_find_left_extents(
|
|
struct xfs_btree_cur *cur,
|
|
struct xfs_refcount_irec *left,
|
|
struct xfs_refcount_irec *cleft,
|
|
xfs_agblock_t agbno,
|
|
xfs_extlen_t aglen,
|
|
int flags)
|
|
{
|
|
struct xfs_refcount_irec tmp;
|
|
int error;
|
|
int found_rec;
|
|
|
|
left->rc_startblock = cleft->rc_startblock = NULLAGBLOCK;
|
|
error = xfs_refcount_lookup_le(cur, agbno - 1, &found_rec);
|
|
if (error)
|
|
goto out_error;
|
|
if (!found_rec)
|
|
return 0;
|
|
|
|
error = xfs_refcount_get_rec(cur, &tmp, &found_rec);
|
|
if (error)
|
|
goto out_error;
|
|
XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, found_rec == 1, out_error);
|
|
|
|
if (xfs_refc_next(&tmp) != agbno)
|
|
return 0;
|
|
if ((flags & XFS_FIND_RCEXT_SHARED) && tmp.rc_refcount < 2)
|
|
return 0;
|
|
if ((flags & XFS_FIND_RCEXT_COW) && tmp.rc_refcount > 1)
|
|
return 0;
|
|
/* We have a left extent; retrieve (or invent) the next right one */
|
|
*left = tmp;
|
|
|
|
error = xfs_btree_increment(cur, 0, &found_rec);
|
|
if (error)
|
|
goto out_error;
|
|
if (found_rec) {
|
|
error = xfs_refcount_get_rec(cur, &tmp, &found_rec);
|
|
if (error)
|
|
goto out_error;
|
|
XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, found_rec == 1,
|
|
out_error);
|
|
|
|
/* if tmp starts at the end of our range, just use that */
|
|
if (tmp.rc_startblock == agbno)
|
|
*cleft = tmp;
|
|
else {
|
|
/*
|
|
* There's a gap in the refcntbt at the start of the
|
|
* range we're interested in (refcount == 1) so
|
|
* synthesize the implied extent and pass it back.
|
|
* We assume here that the agbno/aglen range was
|
|
* passed in from a data fork extent mapping and
|
|
* therefore is allocated to exactly one owner.
|
|
*/
|
|
cleft->rc_startblock = agbno;
|
|
cleft->rc_blockcount = min(aglen,
|
|
tmp.rc_startblock - agbno);
|
|
cleft->rc_refcount = 1;
|
|
}
|
|
} else {
|
|
/*
|
|
* No extents, so pretend that there's one covering the whole
|
|
* range.
|
|
*/
|
|
cleft->rc_startblock = agbno;
|
|
cleft->rc_blockcount = aglen;
|
|
cleft->rc_refcount = 1;
|
|
}
|
|
trace_xfs_refcount_find_left_extent(cur->bc_mp, cur->bc_private.a.agno,
|
|
left, cleft, agbno);
|
|
return error;
|
|
|
|
out_error:
|
|
trace_xfs_refcount_find_left_extent_error(cur->bc_mp,
|
|
cur->bc_private.a.agno, error, _RET_IP_);
|
|
return error;
|
|
}
|
|
|
|
/*
|
|
* Find the right extent and the one before it (cright). This function
|
|
* assumes that we've already split any extents crossing agbno + aglen.
|
|
*/
|
|
STATIC int
|
|
xfs_refcount_find_right_extents(
|
|
struct xfs_btree_cur *cur,
|
|
struct xfs_refcount_irec *right,
|
|
struct xfs_refcount_irec *cright,
|
|
xfs_agblock_t agbno,
|
|
xfs_extlen_t aglen,
|
|
int flags)
|
|
{
|
|
struct xfs_refcount_irec tmp;
|
|
int error;
|
|
int found_rec;
|
|
|
|
right->rc_startblock = cright->rc_startblock = NULLAGBLOCK;
|
|
error = xfs_refcount_lookup_ge(cur, agbno + aglen, &found_rec);
|
|
if (error)
|
|
goto out_error;
|
|
if (!found_rec)
|
|
return 0;
|
|
|
|
error = xfs_refcount_get_rec(cur, &tmp, &found_rec);
|
|
if (error)
|
|
goto out_error;
|
|
XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, found_rec == 1, out_error);
|
|
|
|
if (tmp.rc_startblock != agbno + aglen)
|
|
return 0;
|
|
if ((flags & XFS_FIND_RCEXT_SHARED) && tmp.rc_refcount < 2)
|
|
return 0;
|
|
if ((flags & XFS_FIND_RCEXT_COW) && tmp.rc_refcount > 1)
|
|
return 0;
|
|
/* We have a right extent; retrieve (or invent) the next left one */
|
|
*right = tmp;
|
|
|
|
error = xfs_btree_decrement(cur, 0, &found_rec);
|
|
if (error)
|
|
goto out_error;
|
|
if (found_rec) {
|
|
error = xfs_refcount_get_rec(cur, &tmp, &found_rec);
|
|
if (error)
|
|
goto out_error;
|
|
XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, found_rec == 1,
|
|
out_error);
|
|
|
|
/* if tmp ends at the end of our range, just use that */
|
|
if (xfs_refc_next(&tmp) == agbno + aglen)
|
|
*cright = tmp;
|
|
else {
|
|
/*
|
|
* There's a gap in the refcntbt at the end of the
|
|
* range we're interested in (refcount == 1) so
|
|
* create the implied extent and pass it back.
|
|
* We assume here that the agbno/aglen range was
|
|
* passed in from a data fork extent mapping and
|
|
* therefore is allocated to exactly one owner.
|
|
*/
|
|
cright->rc_startblock = max(agbno, xfs_refc_next(&tmp));
|
|
cright->rc_blockcount = right->rc_startblock -
|
|
cright->rc_startblock;
|
|
cright->rc_refcount = 1;
|
|
}
|
|
} else {
|
|
/*
|
|
* No extents, so pretend that there's one covering the whole
|
|
* range.
|
|
*/
|
|
cright->rc_startblock = agbno;
|
|
cright->rc_blockcount = aglen;
|
|
cright->rc_refcount = 1;
|
|
}
|
|
trace_xfs_refcount_find_right_extent(cur->bc_mp, cur->bc_private.a.agno,
|
|
cright, right, agbno + aglen);
|
|
return error;
|
|
|
|
out_error:
|
|
trace_xfs_refcount_find_right_extent_error(cur->bc_mp,
|
|
cur->bc_private.a.agno, error, _RET_IP_);
|
|
return error;
|
|
}
|
|
|
|
/* Is this extent valid? */
|
|
static inline bool
|
|
xfs_refc_valid(
|
|
struct xfs_refcount_irec *rc)
|
|
{
|
|
return rc->rc_startblock != NULLAGBLOCK;
|
|
}
|
|
|
|
/*
|
|
* Try to merge with any extents on the boundaries of the adjustment range.
|
|
*/
|
|
STATIC int
|
|
xfs_refcount_merge_extents(
|
|
struct xfs_btree_cur *cur,
|
|
xfs_agblock_t *agbno,
|
|
xfs_extlen_t *aglen,
|
|
enum xfs_refc_adjust_op adjust,
|
|
int flags,
|
|
bool *shape_changed)
|
|
{
|
|
struct xfs_refcount_irec left = {0}, cleft = {0};
|
|
struct xfs_refcount_irec cright = {0}, right = {0};
|
|
int error;
|
|
unsigned long long ulen;
|
|
bool cequal;
|
|
|
|
*shape_changed = false;
|
|
/*
|
|
* Find the extent just below agbno [left], just above agbno [cleft],
|
|
* just below (agbno + aglen) [cright], and just above (agbno + aglen)
|
|
* [right].
|
|
*/
|
|
error = xfs_refcount_find_left_extents(cur, &left, &cleft, *agbno,
|
|
*aglen, flags);
|
|
if (error)
|
|
return error;
|
|
error = xfs_refcount_find_right_extents(cur, &right, &cright, *agbno,
|
|
*aglen, flags);
|
|
if (error)
|
|
return error;
|
|
|
|
/* No left or right extent to merge; exit. */
|
|
if (!xfs_refc_valid(&left) && !xfs_refc_valid(&right))
|
|
return 0;
|
|
|
|
cequal = (cleft.rc_startblock == cright.rc_startblock) &&
|
|
(cleft.rc_blockcount == cright.rc_blockcount);
|
|
|
|
/* Try to merge left, cleft, and right. cleft must == cright. */
|
|
ulen = (unsigned long long)left.rc_blockcount + cleft.rc_blockcount +
|
|
right.rc_blockcount;
|
|
if (xfs_refc_valid(&left) && xfs_refc_valid(&right) &&
|
|
xfs_refc_valid(&cleft) && xfs_refc_valid(&cright) && cequal &&
|
|
left.rc_refcount == cleft.rc_refcount + adjust &&
|
|
right.rc_refcount == cleft.rc_refcount + adjust &&
|
|
ulen < MAXREFCEXTLEN) {
|
|
*shape_changed = true;
|
|
return xfs_refcount_merge_center_extents(cur, &left, &cleft,
|
|
&right, ulen, agbno, aglen);
|
|
}
|
|
|
|
/* Try to merge left and cleft. */
|
|
ulen = (unsigned long long)left.rc_blockcount + cleft.rc_blockcount;
|
|
if (xfs_refc_valid(&left) && xfs_refc_valid(&cleft) &&
|
|
left.rc_refcount == cleft.rc_refcount + adjust &&
|
|
ulen < MAXREFCEXTLEN) {
|
|
*shape_changed = true;
|
|
error = xfs_refcount_merge_left_extent(cur, &left, &cleft,
|
|
agbno, aglen);
|
|
if (error)
|
|
return error;
|
|
|
|
/*
|
|
* If we just merged left + cleft and cleft == cright,
|
|
* we no longer have a cright to merge with right. We're done.
|
|
*/
|
|
if (cequal)
|
|
return 0;
|
|
}
|
|
|
|
/* Try to merge cright and right. */
|
|
ulen = (unsigned long long)right.rc_blockcount + cright.rc_blockcount;
|
|
if (xfs_refc_valid(&right) && xfs_refc_valid(&cright) &&
|
|
right.rc_refcount == cright.rc_refcount + adjust &&
|
|
ulen < MAXREFCEXTLEN) {
|
|
*shape_changed = true;
|
|
return xfs_refcount_merge_right_extent(cur, &right, &cright,
|
|
agbno, aglen);
|
|
}
|
|
|
|
return error;
|
|
}
|
|
|
|
/*
|
|
* While we're adjusting the refcounts records of an extent, we have
|
|
* to keep an eye on the number of extents we're dirtying -- run too
|
|
* many in a single transaction and we'll exceed the transaction's
|
|
* reservation and crash the fs. Each record adds 12 bytes to the
|
|
* log (plus any key updates) so we'll conservatively assume 24 bytes
|
|
* per record. We must also leave space for btree splits on both ends
|
|
* of the range and space for the CUD and a new CUI.
|
|
*
|
|
* XXX: This is a pretty hand-wavy estimate. The penalty for guessing
|
|
* true incorrectly is a shutdown FS; the penalty for guessing false
|
|
* incorrectly is more transaction rolls than might be necessary.
|
|
* Be conservative here.
|
|
*/
|
|
static bool
|
|
xfs_refcount_still_have_space(
|
|
struct xfs_btree_cur *cur)
|
|
{
|
|
unsigned long overhead;
|
|
|
|
overhead = cur->bc_private.a.priv.refc.shape_changes *
|
|
xfs_allocfree_log_count(cur->bc_mp, 1);
|
|
overhead *= cur->bc_mp->m_sb.sb_blocksize;
|
|
|
|
/*
|
|
* Only allow 2 refcount extent updates per transaction if the
|
|
* refcount continue update "error" has been injected.
|
|
*/
|
|
if (cur->bc_private.a.priv.refc.nr_ops > 2 &&
|
|
XFS_TEST_ERROR(false, cur->bc_mp,
|
|
XFS_ERRTAG_REFCOUNT_CONTINUE_UPDATE,
|
|
XFS_RANDOM_REFCOUNT_CONTINUE_UPDATE))
|
|
return false;
|
|
|
|
if (cur->bc_private.a.priv.refc.nr_ops == 0)
|
|
return true;
|
|
else if (overhead > cur->bc_tp->t_log_res)
|
|
return false;
|
|
return cur->bc_tp->t_log_res - overhead >
|
|
cur->bc_private.a.priv.refc.nr_ops * 32;
|
|
}
|
|
|
|
/*
|
|
* Adjust the refcounts of middle extents. At this point we should have
|
|
* split extents that crossed the adjustment range; merged with adjacent
|
|
* extents; and updated agbno/aglen to reflect the merges. Therefore,
|
|
* all we have to do is update the extents inside [agbno, agbno + aglen].
|
|
*/
|
|
STATIC int
|
|
xfs_refcount_adjust_extents(
|
|
struct xfs_btree_cur *cur,
|
|
xfs_agblock_t *agbno,
|
|
xfs_extlen_t *aglen,
|
|
enum xfs_refc_adjust_op adj,
|
|
struct xfs_defer_ops *dfops,
|
|
struct xfs_owner_info *oinfo)
|
|
{
|
|
struct xfs_refcount_irec ext, tmp;
|
|
int error;
|
|
int found_rec, found_tmp;
|
|
xfs_fsblock_t fsbno;
|
|
|
|
/* Merging did all the work already. */
|
|
if (*aglen == 0)
|
|
return 0;
|
|
|
|
error = xfs_refcount_lookup_ge(cur, *agbno, &found_rec);
|
|
if (error)
|
|
goto out_error;
|
|
|
|
while (*aglen > 0 && xfs_refcount_still_have_space(cur)) {
|
|
error = xfs_refcount_get_rec(cur, &ext, &found_rec);
|
|
if (error)
|
|
goto out_error;
|
|
if (!found_rec) {
|
|
ext.rc_startblock = cur->bc_mp->m_sb.sb_agblocks;
|
|
ext.rc_blockcount = 0;
|
|
ext.rc_refcount = 0;
|
|
}
|
|
|
|
/*
|
|
* Deal with a hole in the refcount tree; if a file maps to
|
|
* these blocks and there's no refcountbt record, pretend that
|
|
* there is one with refcount == 1.
|
|
*/
|
|
if (ext.rc_startblock != *agbno) {
|
|
tmp.rc_startblock = *agbno;
|
|
tmp.rc_blockcount = min(*aglen,
|
|
ext.rc_startblock - *agbno);
|
|
tmp.rc_refcount = 1 + adj;
|
|
trace_xfs_refcount_modify_extent(cur->bc_mp,
|
|
cur->bc_private.a.agno, &tmp);
|
|
|
|
/*
|
|
* Either cover the hole (increment) or
|
|
* delete the range (decrement).
|
|
*/
|
|
if (tmp.rc_refcount) {
|
|
error = xfs_refcount_insert(cur, &tmp,
|
|
&found_tmp);
|
|
if (error)
|
|
goto out_error;
|
|
XFS_WANT_CORRUPTED_GOTO(cur->bc_mp,
|
|
found_tmp == 1, out_error);
|
|
cur->bc_private.a.priv.refc.nr_ops++;
|
|
} else {
|
|
fsbno = XFS_AGB_TO_FSB(cur->bc_mp,
|
|
cur->bc_private.a.agno,
|
|
tmp.rc_startblock);
|
|
xfs_bmap_add_free(cur->bc_mp, dfops, fsbno,
|
|
tmp.rc_blockcount, oinfo);
|
|
}
|
|
|
|
(*agbno) += tmp.rc_blockcount;
|
|
(*aglen) -= tmp.rc_blockcount;
|
|
|
|
error = xfs_refcount_lookup_ge(cur, *agbno,
|
|
&found_rec);
|
|
if (error)
|
|
goto out_error;
|
|
}
|
|
|
|
/* Stop if there's nothing left to modify */
|
|
if (*aglen == 0 || !xfs_refcount_still_have_space(cur))
|
|
break;
|
|
|
|
/*
|
|
* Adjust the reference count and either update the tree
|
|
* (incr) or free the blocks (decr).
|
|
*/
|
|
if (ext.rc_refcount == MAXREFCOUNT)
|
|
goto skip;
|
|
ext.rc_refcount += adj;
|
|
trace_xfs_refcount_modify_extent(cur->bc_mp,
|
|
cur->bc_private.a.agno, &ext);
|
|
if (ext.rc_refcount > 1) {
|
|
error = xfs_refcount_update(cur, &ext);
|
|
if (error)
|
|
goto out_error;
|
|
cur->bc_private.a.priv.refc.nr_ops++;
|
|
} else if (ext.rc_refcount == 1) {
|
|
error = xfs_refcount_delete(cur, &found_rec);
|
|
if (error)
|
|
goto out_error;
|
|
XFS_WANT_CORRUPTED_GOTO(cur->bc_mp,
|
|
found_rec == 1, out_error);
|
|
cur->bc_private.a.priv.refc.nr_ops++;
|
|
goto advloop;
|
|
} else {
|
|
fsbno = XFS_AGB_TO_FSB(cur->bc_mp,
|
|
cur->bc_private.a.agno,
|
|
ext.rc_startblock);
|
|
xfs_bmap_add_free(cur->bc_mp, dfops, fsbno,
|
|
ext.rc_blockcount, oinfo);
|
|
}
|
|
|
|
skip:
|
|
error = xfs_btree_increment(cur, 0, &found_rec);
|
|
if (error)
|
|
goto out_error;
|
|
|
|
advloop:
|
|
(*agbno) += ext.rc_blockcount;
|
|
(*aglen) -= ext.rc_blockcount;
|
|
}
|
|
|
|
return error;
|
|
out_error:
|
|
trace_xfs_refcount_modify_extent_error(cur->bc_mp,
|
|
cur->bc_private.a.agno, error, _RET_IP_);
|
|
return error;
|
|
}
|
|
|
|
/* Adjust the reference count of a range of AG blocks. */
|
|
STATIC int
|
|
xfs_refcount_adjust(
|
|
struct xfs_btree_cur *cur,
|
|
xfs_agblock_t agbno,
|
|
xfs_extlen_t aglen,
|
|
xfs_agblock_t *new_agbno,
|
|
xfs_extlen_t *new_aglen,
|
|
enum xfs_refc_adjust_op adj,
|
|
struct xfs_defer_ops *dfops,
|
|
struct xfs_owner_info *oinfo)
|
|
{
|
|
bool shape_changed;
|
|
int shape_changes = 0;
|
|
int error;
|
|
|
|
*new_agbno = agbno;
|
|
*new_aglen = aglen;
|
|
if (adj == XFS_REFCOUNT_ADJUST_INCREASE)
|
|
trace_xfs_refcount_increase(cur->bc_mp, cur->bc_private.a.agno,
|
|
agbno, aglen);
|
|
else
|
|
trace_xfs_refcount_decrease(cur->bc_mp, cur->bc_private.a.agno,
|
|
agbno, aglen);
|
|
|
|
/*
|
|
* Ensure that no rcextents cross the boundary of the adjustment range.
|
|
*/
|
|
error = xfs_refcount_split_extent(cur, agbno, &shape_changed);
|
|
if (error)
|
|
goto out_error;
|
|
if (shape_changed)
|
|
shape_changes++;
|
|
|
|
error = xfs_refcount_split_extent(cur, agbno + aglen, &shape_changed);
|
|
if (error)
|
|
goto out_error;
|
|
if (shape_changed)
|
|
shape_changes++;
|
|
|
|
/*
|
|
* Try to merge with the left or right extents of the range.
|
|
*/
|
|
error = xfs_refcount_merge_extents(cur, new_agbno, new_aglen, adj,
|
|
XFS_FIND_RCEXT_SHARED, &shape_changed);
|
|
if (error)
|
|
goto out_error;
|
|
if (shape_changed)
|
|
shape_changes++;
|
|
if (shape_changes)
|
|
cur->bc_private.a.priv.refc.shape_changes++;
|
|
|
|
/* Now that we've taken care of the ends, adjust the middle extents */
|
|
error = xfs_refcount_adjust_extents(cur, new_agbno, new_aglen,
|
|
adj, dfops, oinfo);
|
|
if (error)
|
|
goto out_error;
|
|
|
|
return 0;
|
|
|
|
out_error:
|
|
trace_xfs_refcount_adjust_error(cur->bc_mp, cur->bc_private.a.agno,
|
|
error, _RET_IP_);
|
|
return error;
|
|
}
|
|
|
|
/* Clean up after calling xfs_refcount_finish_one. */
|
|
void
|
|
xfs_refcount_finish_one_cleanup(
|
|
struct xfs_trans *tp,
|
|
struct xfs_btree_cur *rcur,
|
|
int error)
|
|
{
|
|
struct xfs_buf *agbp;
|
|
|
|
if (rcur == NULL)
|
|
return;
|
|
agbp = rcur->bc_private.a.agbp;
|
|
xfs_btree_del_cursor(rcur, error ? XFS_BTREE_ERROR : XFS_BTREE_NOERROR);
|
|
if (error)
|
|
xfs_trans_brelse(tp, agbp);
|
|
}
|
|
|
|
/*
|
|
* Process one of the deferred refcount operations. We pass back the
|
|
* btree cursor to maintain our lock on the btree between calls.
|
|
* This saves time and eliminates a buffer deadlock between the
|
|
* superblock and the AGF because we'll always grab them in the same
|
|
* order.
|
|
*/
|
|
int
|
|
xfs_refcount_finish_one(
|
|
struct xfs_trans *tp,
|
|
struct xfs_defer_ops *dfops,
|
|
enum xfs_refcount_intent_type type,
|
|
xfs_fsblock_t startblock,
|
|
xfs_extlen_t blockcount,
|
|
xfs_fsblock_t *new_fsb,
|
|
xfs_extlen_t *new_len,
|
|
struct xfs_btree_cur **pcur)
|
|
{
|
|
struct xfs_mount *mp = tp->t_mountp;
|
|
struct xfs_btree_cur *rcur;
|
|
struct xfs_buf *agbp = NULL;
|
|
int error = 0;
|
|
xfs_agnumber_t agno;
|
|
xfs_agblock_t bno;
|
|
xfs_agblock_t new_agbno;
|
|
unsigned long nr_ops = 0;
|
|
int shape_changes = 0;
|
|
|
|
agno = XFS_FSB_TO_AGNO(mp, startblock);
|
|
ASSERT(agno != NULLAGNUMBER);
|
|
bno = XFS_FSB_TO_AGBNO(mp, startblock);
|
|
|
|
trace_xfs_refcount_deferred(mp, XFS_FSB_TO_AGNO(mp, startblock),
|
|
type, XFS_FSB_TO_AGBNO(mp, startblock),
|
|
blockcount);
|
|
|
|
if (XFS_TEST_ERROR(false, mp,
|
|
XFS_ERRTAG_REFCOUNT_FINISH_ONE,
|
|
XFS_RANDOM_REFCOUNT_FINISH_ONE))
|
|
return -EIO;
|
|
|
|
/*
|
|
* If we haven't gotten a cursor or the cursor AG doesn't match
|
|
* the startblock, get one now.
|
|
*/
|
|
rcur = *pcur;
|
|
if (rcur != NULL && rcur->bc_private.a.agno != agno) {
|
|
nr_ops = rcur->bc_private.a.priv.refc.nr_ops;
|
|
shape_changes = rcur->bc_private.a.priv.refc.shape_changes;
|
|
xfs_refcount_finish_one_cleanup(tp, rcur, 0);
|
|
rcur = NULL;
|
|
*pcur = NULL;
|
|
}
|
|
if (rcur == NULL) {
|
|
error = xfs_alloc_read_agf(tp->t_mountp, tp, agno,
|
|
XFS_ALLOC_FLAG_FREEING, &agbp);
|
|
if (error)
|
|
return error;
|
|
if (!agbp)
|
|
return -EFSCORRUPTED;
|
|
|
|
rcur = xfs_refcountbt_init_cursor(mp, tp, agbp, agno, dfops);
|
|
if (!rcur) {
|
|
error = -ENOMEM;
|
|
goto out_cur;
|
|
}
|
|
rcur->bc_private.a.priv.refc.nr_ops = nr_ops;
|
|
rcur->bc_private.a.priv.refc.shape_changes = shape_changes;
|
|
}
|
|
*pcur = rcur;
|
|
|
|
switch (type) {
|
|
case XFS_REFCOUNT_INCREASE:
|
|
error = xfs_refcount_adjust(rcur, bno, blockcount, &new_agbno,
|
|
new_len, XFS_REFCOUNT_ADJUST_INCREASE, dfops, NULL);
|
|
*new_fsb = XFS_AGB_TO_FSB(mp, agno, new_agbno);
|
|
break;
|
|
case XFS_REFCOUNT_DECREASE:
|
|
error = xfs_refcount_adjust(rcur, bno, blockcount, &new_agbno,
|
|
new_len, XFS_REFCOUNT_ADJUST_DECREASE, dfops, NULL);
|
|
*new_fsb = XFS_AGB_TO_FSB(mp, agno, new_agbno);
|
|
break;
|
|
case XFS_REFCOUNT_ALLOC_COW:
|
|
*new_fsb = startblock + blockcount;
|
|
*new_len = 0;
|
|
error = __xfs_refcount_cow_alloc(rcur, bno, blockcount, dfops);
|
|
break;
|
|
case XFS_REFCOUNT_FREE_COW:
|
|
*new_fsb = startblock + blockcount;
|
|
*new_len = 0;
|
|
error = __xfs_refcount_cow_free(rcur, bno, blockcount, dfops);
|
|
break;
|
|
default:
|
|
ASSERT(0);
|
|
error = -EFSCORRUPTED;
|
|
}
|
|
if (!error && *new_len > 0)
|
|
trace_xfs_refcount_finish_one_leftover(mp, agno, type,
|
|
bno, blockcount, new_agbno, *new_len);
|
|
return error;
|
|
|
|
out_cur:
|
|
xfs_trans_brelse(tp, agbp);
|
|
|
|
return error;
|
|
}
|
|
|
|
/*
|
|
* Record a refcount intent for later processing.
|
|
*/
|
|
static int
|
|
__xfs_refcount_add(
|
|
struct xfs_mount *mp,
|
|
struct xfs_defer_ops *dfops,
|
|
enum xfs_refcount_intent_type type,
|
|
xfs_fsblock_t startblock,
|
|
xfs_extlen_t blockcount)
|
|
{
|
|
struct xfs_refcount_intent *ri;
|
|
|
|
trace_xfs_refcount_defer(mp, XFS_FSB_TO_AGNO(mp, startblock),
|
|
type, XFS_FSB_TO_AGBNO(mp, startblock),
|
|
blockcount);
|
|
|
|
ri = kmem_alloc(sizeof(struct xfs_refcount_intent),
|
|
KM_SLEEP | KM_NOFS);
|
|
INIT_LIST_HEAD(&ri->ri_list);
|
|
ri->ri_type = type;
|
|
ri->ri_startblock = startblock;
|
|
ri->ri_blockcount = blockcount;
|
|
|
|
xfs_defer_add(dfops, XFS_DEFER_OPS_TYPE_REFCOUNT, &ri->ri_list);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Increase the reference count of the blocks backing a file's extent.
|
|
*/
|
|
int
|
|
xfs_refcount_increase_extent(
|
|
struct xfs_mount *mp,
|
|
struct xfs_defer_ops *dfops,
|
|
struct xfs_bmbt_irec *PREV)
|
|
{
|
|
if (!xfs_sb_version_hasreflink(&mp->m_sb))
|
|
return 0;
|
|
|
|
return __xfs_refcount_add(mp, dfops, XFS_REFCOUNT_INCREASE,
|
|
PREV->br_startblock, PREV->br_blockcount);
|
|
}
|
|
|
|
/*
|
|
* Decrease the reference count of the blocks backing a file's extent.
|
|
*/
|
|
int
|
|
xfs_refcount_decrease_extent(
|
|
struct xfs_mount *mp,
|
|
struct xfs_defer_ops *dfops,
|
|
struct xfs_bmbt_irec *PREV)
|
|
{
|
|
if (!xfs_sb_version_hasreflink(&mp->m_sb))
|
|
return 0;
|
|
|
|
return __xfs_refcount_add(mp, dfops, XFS_REFCOUNT_DECREASE,
|
|
PREV->br_startblock, PREV->br_blockcount);
|
|
}
|
|
|
|
/*
|
|
* Given an AG extent, find the lowest-numbered run of shared blocks
|
|
* within that range and return the range in fbno/flen. If
|
|
* find_end_of_shared is set, return the longest contiguous extent of
|
|
* shared blocks; if not, just return the first extent we find. If no
|
|
* shared blocks are found, fbno and flen will be set to NULLAGBLOCK
|
|
* and 0, respectively.
|
|
*/
|
|
int
|
|
xfs_refcount_find_shared(
|
|
struct xfs_btree_cur *cur,
|
|
xfs_agblock_t agbno,
|
|
xfs_extlen_t aglen,
|
|
xfs_agblock_t *fbno,
|
|
xfs_extlen_t *flen,
|
|
bool find_end_of_shared)
|
|
{
|
|
struct xfs_refcount_irec tmp;
|
|
int i;
|
|
int have;
|
|
int error;
|
|
|
|
trace_xfs_refcount_find_shared(cur->bc_mp, cur->bc_private.a.agno,
|
|
agbno, aglen);
|
|
|
|
/* By default, skip the whole range */
|
|
*fbno = NULLAGBLOCK;
|
|
*flen = 0;
|
|
|
|
/* Try to find a refcount extent that crosses the start */
|
|
error = xfs_refcount_lookup_le(cur, agbno, &have);
|
|
if (error)
|
|
goto out_error;
|
|
if (!have) {
|
|
/* No left extent, look at the next one */
|
|
error = xfs_btree_increment(cur, 0, &have);
|
|
if (error)
|
|
goto out_error;
|
|
if (!have)
|
|
goto done;
|
|
}
|
|
error = xfs_refcount_get_rec(cur, &tmp, &i);
|
|
if (error)
|
|
goto out_error;
|
|
XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, i == 1, out_error);
|
|
|
|
/* If the extent ends before the start, look at the next one */
|
|
if (tmp.rc_startblock + tmp.rc_blockcount <= agbno) {
|
|
error = xfs_btree_increment(cur, 0, &have);
|
|
if (error)
|
|
goto out_error;
|
|
if (!have)
|
|
goto done;
|
|
error = xfs_refcount_get_rec(cur, &tmp, &i);
|
|
if (error)
|
|
goto out_error;
|
|
XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, i == 1, out_error);
|
|
}
|
|
|
|
/* If the extent starts after the range we want, bail out */
|
|
if (tmp.rc_startblock >= agbno + aglen)
|
|
goto done;
|
|
|
|
/* We found the start of a shared extent! */
|
|
if (tmp.rc_startblock < agbno) {
|
|
tmp.rc_blockcount -= (agbno - tmp.rc_startblock);
|
|
tmp.rc_startblock = agbno;
|
|
}
|
|
|
|
*fbno = tmp.rc_startblock;
|
|
*flen = min(tmp.rc_blockcount, agbno + aglen - *fbno);
|
|
if (!find_end_of_shared)
|
|
goto done;
|
|
|
|
/* Otherwise, find the end of this shared extent */
|
|
while (*fbno + *flen < agbno + aglen) {
|
|
error = xfs_btree_increment(cur, 0, &have);
|
|
if (error)
|
|
goto out_error;
|
|
if (!have)
|
|
break;
|
|
error = xfs_refcount_get_rec(cur, &tmp, &i);
|
|
if (error)
|
|
goto out_error;
|
|
XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, i == 1, out_error);
|
|
if (tmp.rc_startblock >= agbno + aglen ||
|
|
tmp.rc_startblock != *fbno + *flen)
|
|
break;
|
|
*flen = min(*flen + tmp.rc_blockcount, agbno + aglen - *fbno);
|
|
}
|
|
|
|
done:
|
|
trace_xfs_refcount_find_shared_result(cur->bc_mp,
|
|
cur->bc_private.a.agno, *fbno, *flen);
|
|
|
|
out_error:
|
|
if (error)
|
|
trace_xfs_refcount_find_shared_error(cur->bc_mp,
|
|
cur->bc_private.a.agno, error, _RET_IP_);
|
|
return error;
|
|
}
|
|
|
|
/*
|
|
* Recovering CoW Blocks After a Crash
|
|
*
|
|
* Due to the way that the copy on write mechanism works, there's a window of
|
|
* opportunity in which we can lose track of allocated blocks during a crash.
|
|
* Because CoW uses delayed allocation in the in-core CoW fork, writeback
|
|
* causes blocks to be allocated and stored in the CoW fork. The blocks are
|
|
* no longer in the free space btree but are not otherwise recorded anywhere
|
|
* until the write completes and the blocks are mapped into the file. A crash
|
|
* in between allocation and remapping results in the replacement blocks being
|
|
* lost. This situation is exacerbated by the CoW extent size hint because
|
|
* allocations can hang around for long time.
|
|
*
|
|
* However, there is a place where we can record these allocations before they
|
|
* become mappings -- the reference count btree. The btree does not record
|
|
* extents with refcount == 1, so we can record allocations with a refcount of
|
|
* 1. Blocks being used for CoW writeout cannot be shared, so there should be
|
|
* no conflict with shared block records. These mappings should be created
|
|
* when we allocate blocks to the CoW fork and deleted when they're removed
|
|
* from the CoW fork.
|
|
*
|
|
* Minor nit: records for in-progress CoW allocations and records for shared
|
|
* extents must never be merged, to preserve the property that (except for CoW
|
|
* allocations) there are no refcount btree entries with refcount == 1. The
|
|
* only time this could potentially happen is when unsharing a block that's
|
|
* adjacent to CoW allocations, so we must be careful to avoid this.
|
|
*
|
|
* At mount time we recover lost CoW allocations by searching the refcount
|
|
* btree for these refcount == 1 mappings. These represent CoW allocations
|
|
* that were in progress at the time the filesystem went down, so we can free
|
|
* them to get the space back.
|
|
*
|
|
* This mechanism is superior to creating EFIs for unmapped CoW extents for
|
|
* several reasons -- first, EFIs pin the tail of the log and would have to be
|
|
* periodically relogged to avoid filling up the log. Second, CoW completions
|
|
* will have to file an EFD and create new EFIs for whatever remains in the
|
|
* CoW fork; this partially takes care of (1) but extent-size reservations
|
|
* will have to periodically relog even if there's no writeout in progress.
|
|
* This can happen if the CoW extent size hint is set, which you really want.
|
|
* Third, EFIs cannot currently be automatically relogged into newer
|
|
* transactions to advance the log tail. Fourth, stuffing the log full of
|
|
* EFIs places an upper bound on the number of CoW allocations that can be
|
|
* held filesystem-wide at any given time. Recording them in the refcount
|
|
* btree doesn't require us to maintain any state in memory and doesn't pin
|
|
* the log.
|
|
*/
|
|
/*
|
|
* Adjust the refcounts of CoW allocations. These allocations are "magic"
|
|
* in that they're not referenced anywhere else in the filesystem, so we
|
|
* stash them in the refcount btree with a refcount of 1 until either file
|
|
* remapping (or CoW cancellation) happens.
|
|
*/
|
|
STATIC int
|
|
xfs_refcount_adjust_cow_extents(
|
|
struct xfs_btree_cur *cur,
|
|
xfs_agblock_t agbno,
|
|
xfs_extlen_t aglen,
|
|
enum xfs_refc_adjust_op adj,
|
|
struct xfs_defer_ops *dfops,
|
|
struct xfs_owner_info *oinfo)
|
|
{
|
|
struct xfs_refcount_irec ext, tmp;
|
|
int error;
|
|
int found_rec, found_tmp;
|
|
|
|
if (aglen == 0)
|
|
return 0;
|
|
|
|
/* Find any overlapping refcount records */
|
|
error = xfs_refcount_lookup_ge(cur, agbno, &found_rec);
|
|
if (error)
|
|
goto out_error;
|
|
error = xfs_refcount_get_rec(cur, &ext, &found_rec);
|
|
if (error)
|
|
goto out_error;
|
|
if (!found_rec) {
|
|
ext.rc_startblock = cur->bc_mp->m_sb.sb_agblocks +
|
|
XFS_REFC_COW_START;
|
|
ext.rc_blockcount = 0;
|
|
ext.rc_refcount = 0;
|
|
}
|
|
|
|
switch (adj) {
|
|
case XFS_REFCOUNT_ADJUST_COW_ALLOC:
|
|
/* Adding a CoW reservation, there should be nothing here. */
|
|
XFS_WANT_CORRUPTED_GOTO(cur->bc_mp,
|
|
ext.rc_startblock >= agbno + aglen, out_error);
|
|
|
|
tmp.rc_startblock = agbno;
|
|
tmp.rc_blockcount = aglen;
|
|
tmp.rc_refcount = 1;
|
|
trace_xfs_refcount_modify_extent(cur->bc_mp,
|
|
cur->bc_private.a.agno, &tmp);
|
|
|
|
error = xfs_refcount_insert(cur, &tmp,
|
|
&found_tmp);
|
|
if (error)
|
|
goto out_error;
|
|
XFS_WANT_CORRUPTED_GOTO(cur->bc_mp,
|
|
found_tmp == 1, out_error);
|
|
break;
|
|
case XFS_REFCOUNT_ADJUST_COW_FREE:
|
|
/* Removing a CoW reservation, there should be one extent. */
|
|
XFS_WANT_CORRUPTED_GOTO(cur->bc_mp,
|
|
ext.rc_startblock == agbno, out_error);
|
|
XFS_WANT_CORRUPTED_GOTO(cur->bc_mp,
|
|
ext.rc_blockcount == aglen, out_error);
|
|
XFS_WANT_CORRUPTED_GOTO(cur->bc_mp,
|
|
ext.rc_refcount == 1, out_error);
|
|
|
|
ext.rc_refcount = 0;
|
|
trace_xfs_refcount_modify_extent(cur->bc_mp,
|
|
cur->bc_private.a.agno, &ext);
|
|
error = xfs_refcount_delete(cur, &found_rec);
|
|
if (error)
|
|
goto out_error;
|
|
XFS_WANT_CORRUPTED_GOTO(cur->bc_mp,
|
|
found_rec == 1, out_error);
|
|
break;
|
|
default:
|
|
ASSERT(0);
|
|
}
|
|
|
|
return error;
|
|
out_error:
|
|
trace_xfs_refcount_modify_extent_error(cur->bc_mp,
|
|
cur->bc_private.a.agno, error, _RET_IP_);
|
|
return error;
|
|
}
|
|
|
|
/*
|
|
* Add or remove refcount btree entries for CoW reservations.
|
|
*/
|
|
STATIC int
|
|
xfs_refcount_adjust_cow(
|
|
struct xfs_btree_cur *cur,
|
|
xfs_agblock_t agbno,
|
|
xfs_extlen_t aglen,
|
|
enum xfs_refc_adjust_op adj,
|
|
struct xfs_defer_ops *dfops)
|
|
{
|
|
bool shape_changed;
|
|
int error;
|
|
|
|
agbno += XFS_REFC_COW_START;
|
|
|
|
/*
|
|
* Ensure that no rcextents cross the boundary of the adjustment range.
|
|
*/
|
|
error = xfs_refcount_split_extent(cur, agbno, &shape_changed);
|
|
if (error)
|
|
goto out_error;
|
|
|
|
error = xfs_refcount_split_extent(cur, agbno + aglen, &shape_changed);
|
|
if (error)
|
|
goto out_error;
|
|
|
|
/*
|
|
* Try to merge with the left or right extents of the range.
|
|
*/
|
|
error = xfs_refcount_merge_extents(cur, &agbno, &aglen, adj,
|
|
XFS_FIND_RCEXT_COW, &shape_changed);
|
|
if (error)
|
|
goto out_error;
|
|
|
|
/* Now that we've taken care of the ends, adjust the middle extents */
|
|
error = xfs_refcount_adjust_cow_extents(cur, agbno, aglen, adj,
|
|
dfops, NULL);
|
|
if (error)
|
|
goto out_error;
|
|
|
|
return 0;
|
|
|
|
out_error:
|
|
trace_xfs_refcount_adjust_cow_error(cur->bc_mp, cur->bc_private.a.agno,
|
|
error, _RET_IP_);
|
|
return error;
|
|
}
|
|
|
|
/*
|
|
* Record a CoW allocation in the refcount btree.
|
|
*/
|
|
STATIC int
|
|
__xfs_refcount_cow_alloc(
|
|
struct xfs_btree_cur *rcur,
|
|
xfs_agblock_t agbno,
|
|
xfs_extlen_t aglen,
|
|
struct xfs_defer_ops *dfops)
|
|
{
|
|
int error;
|
|
|
|
trace_xfs_refcount_cow_increase(rcur->bc_mp, rcur->bc_private.a.agno,
|
|
agbno, aglen);
|
|
|
|
/* Add refcount btree reservation */
|
|
error = xfs_refcount_adjust_cow(rcur, agbno, aglen,
|
|
XFS_REFCOUNT_ADJUST_COW_ALLOC, dfops);
|
|
if (error)
|
|
return error;
|
|
|
|
/* Add rmap entry */
|
|
if (xfs_sb_version_hasrmapbt(&rcur->bc_mp->m_sb)) {
|
|
error = xfs_rmap_alloc_extent(rcur->bc_mp, dfops,
|
|
rcur->bc_private.a.agno,
|
|
agbno, aglen, XFS_RMAP_OWN_COW);
|
|
if (error)
|
|
return error;
|
|
}
|
|
|
|
return error;
|
|
}
|
|
|
|
/*
|
|
* Remove a CoW allocation from the refcount btree.
|
|
*/
|
|
STATIC int
|
|
__xfs_refcount_cow_free(
|
|
struct xfs_btree_cur *rcur,
|
|
xfs_agblock_t agbno,
|
|
xfs_extlen_t aglen,
|
|
struct xfs_defer_ops *dfops)
|
|
{
|
|
int error;
|
|
|
|
trace_xfs_refcount_cow_decrease(rcur->bc_mp, rcur->bc_private.a.agno,
|
|
agbno, aglen);
|
|
|
|
/* Remove refcount btree reservation */
|
|
error = xfs_refcount_adjust_cow(rcur, agbno, aglen,
|
|
XFS_REFCOUNT_ADJUST_COW_FREE, dfops);
|
|
if (error)
|
|
return error;
|
|
|
|
/* Remove rmap entry */
|
|
if (xfs_sb_version_hasrmapbt(&rcur->bc_mp->m_sb)) {
|
|
error = xfs_rmap_free_extent(rcur->bc_mp, dfops,
|
|
rcur->bc_private.a.agno,
|
|
agbno, aglen, XFS_RMAP_OWN_COW);
|
|
if (error)
|
|
return error;
|
|
}
|
|
|
|
return error;
|
|
}
|
|
|
|
/* Record a CoW staging extent in the refcount btree. */
|
|
int
|
|
xfs_refcount_alloc_cow_extent(
|
|
struct xfs_mount *mp,
|
|
struct xfs_defer_ops *dfops,
|
|
xfs_fsblock_t fsb,
|
|
xfs_extlen_t len)
|
|
{
|
|
if (!xfs_sb_version_hasreflink(&mp->m_sb))
|
|
return 0;
|
|
|
|
return __xfs_refcount_add(mp, dfops, XFS_REFCOUNT_ALLOC_COW,
|
|
fsb, len);
|
|
}
|
|
|
|
/* Forget a CoW staging event in the refcount btree. */
|
|
int
|
|
xfs_refcount_free_cow_extent(
|
|
struct xfs_mount *mp,
|
|
struct xfs_defer_ops *dfops,
|
|
xfs_fsblock_t fsb,
|
|
xfs_extlen_t len)
|
|
{
|
|
if (!xfs_sb_version_hasreflink(&mp->m_sb))
|
|
return 0;
|
|
|
|
return __xfs_refcount_add(mp, dfops, XFS_REFCOUNT_FREE_COW,
|
|
fsb, len);
|
|
}
|
|
|
|
struct xfs_refcount_recovery {
|
|
struct list_head rr_list;
|
|
struct xfs_refcount_irec rr_rrec;
|
|
};
|
|
|
|
/* Stuff an extent on the recovery list. */
|
|
STATIC int
|
|
xfs_refcount_recover_extent(
|
|
struct xfs_btree_cur *cur,
|
|
union xfs_btree_rec *rec,
|
|
void *priv)
|
|
{
|
|
struct list_head *debris = priv;
|
|
struct xfs_refcount_recovery *rr;
|
|
|
|
if (be32_to_cpu(rec->refc.rc_refcount) != 1)
|
|
return -EFSCORRUPTED;
|
|
|
|
rr = kmem_alloc(sizeof(struct xfs_refcount_recovery), KM_SLEEP);
|
|
xfs_refcount_btrec_to_irec(rec, &rr->rr_rrec);
|
|
list_add_tail(&rr->rr_list, debris);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/* Find and remove leftover CoW reservations. */
|
|
int
|
|
xfs_refcount_recover_cow_leftovers(
|
|
struct xfs_mount *mp,
|
|
xfs_agnumber_t agno)
|
|
{
|
|
struct xfs_trans *tp;
|
|
struct xfs_btree_cur *cur;
|
|
struct xfs_buf *agbp;
|
|
struct xfs_refcount_recovery *rr, *n;
|
|
struct list_head debris;
|
|
union xfs_btree_irec low;
|
|
union xfs_btree_irec high;
|
|
struct xfs_defer_ops dfops;
|
|
xfs_fsblock_t fsb;
|
|
xfs_agblock_t agbno;
|
|
int error;
|
|
|
|
if (mp->m_sb.sb_agblocks >= XFS_REFC_COW_START)
|
|
return -EOPNOTSUPP;
|
|
|
|
INIT_LIST_HEAD(&debris);
|
|
|
|
/*
|
|
* In this first part, we use an empty transaction to gather up
|
|
* all the leftover CoW extents so that we can subsequently
|
|
* delete them. The empty transaction is used to avoid
|
|
* a buffer lock deadlock if there happens to be a loop in the
|
|
* refcountbt because we're allowed to re-grab a buffer that is
|
|
* already attached to our transaction. When we're done
|
|
* recording the CoW debris we cancel the (empty) transaction
|
|
* and everything goes away cleanly.
|
|
*/
|
|
error = xfs_trans_alloc_empty(mp, &tp);
|
|
if (error)
|
|
return error;
|
|
|
|
error = xfs_alloc_read_agf(mp, tp, agno, 0, &agbp);
|
|
if (error)
|
|
goto out_trans;
|
|
cur = xfs_refcountbt_init_cursor(mp, tp, agbp, agno, NULL);
|
|
|
|
/* Find all the leftover CoW staging extents. */
|
|
memset(&low, 0, sizeof(low));
|
|
memset(&high, 0, sizeof(high));
|
|
low.rc.rc_startblock = XFS_REFC_COW_START;
|
|
high.rc.rc_startblock = -1U;
|
|
error = xfs_btree_query_range(cur, &low, &high,
|
|
xfs_refcount_recover_extent, &debris);
|
|
if (error)
|
|
goto out_cursor;
|
|
xfs_btree_del_cursor(cur, XFS_BTREE_NOERROR);
|
|
xfs_trans_brelse(tp, agbp);
|
|
xfs_trans_cancel(tp);
|
|
|
|
/* Now iterate the list to free the leftovers */
|
|
list_for_each_entry_safe(rr, n, &debris, rr_list) {
|
|
/* Set up transaction. */
|
|
error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write, 0, 0, 0, &tp);
|
|
if (error)
|
|
goto out_free;
|
|
|
|
trace_xfs_refcount_recover_extent(mp, agno, &rr->rr_rrec);
|
|
|
|
/* Free the orphan record */
|
|
xfs_defer_init(&dfops, &fsb);
|
|
agbno = rr->rr_rrec.rc_startblock - XFS_REFC_COW_START;
|
|
fsb = XFS_AGB_TO_FSB(mp, agno, agbno);
|
|
error = xfs_refcount_free_cow_extent(mp, &dfops, fsb,
|
|
rr->rr_rrec.rc_blockcount);
|
|
if (error)
|
|
goto out_defer;
|
|
|
|
/* Free the block. */
|
|
xfs_bmap_add_free(mp, &dfops, fsb,
|
|
rr->rr_rrec.rc_blockcount, NULL);
|
|
|
|
error = xfs_defer_finish(&tp, &dfops, NULL);
|
|
if (error)
|
|
goto out_defer;
|
|
|
|
error = xfs_trans_commit(tp);
|
|
if (error)
|
|
goto out_free;
|
|
|
|
list_del(&rr->rr_list);
|
|
kmem_free(rr);
|
|
}
|
|
|
|
return error;
|
|
out_defer:
|
|
xfs_defer_cancel(&dfops);
|
|
out_trans:
|
|
xfs_trans_cancel(tp);
|
|
out_free:
|
|
/* Free the leftover list */
|
|
list_for_each_entry_safe(rr, n, &debris, rr_list) {
|
|
list_del(&rr->rr_list);
|
|
kmem_free(rr);
|
|
}
|
|
return error;
|
|
|
|
out_cursor:
|
|
xfs_btree_del_cursor(cur, XFS_BTREE_ERROR);
|
|
xfs_trans_brelse(tp, agbp);
|
|
goto out_trans;
|
|
}
|