// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (c) 2014 Red Hat, Inc.
* All Rights Reserved.
*/
#include "xfs.h"
#include "xfs_fs.h"
#include "xfs_shared.h"
#include "xfs_format.h"
#include "xfs_log_format.h"
#include "xfs_trans_resv.h"
#include "xfs_sb.h"
#include "xfs_mount.h"
#include "xfs_trans.h"
#include "xfs_alloc.h"
#include "xfs_btree.h"
#include "xfs_rmap.h"
#include "xfs_rmap_btree.h"
#include "xfs_trace.h"
#include "xfs_error.h"
#include "xfs_extent_busy.h"
#include "xfs_ag_resv.h"
/*
* Reverse map btree.
*
* This is a per-ag tree used to track the owner(s) of a given extent. With
* reflink it is possible for there to be multiple owners, which is a departure
* from classic XFS. Owner records for data extents are inserted when the
* extent is mapped and removed when an extent is unmapped. Owner records for
* all other block types (i.e. metadata) are inserted when an extent is
* allocated and removed when an extent is freed. There can only be one owner
* of a metadata extent, usually an inode or some other metadata structure like
* an AG btree.
*
* The rmap btree is part of the free space management, so blocks for the tree
* are sourced from the agfl. Hence we need transaction reservation support for
* this tree so that the freelist is always large enough. This also impacts on
* the minimum space we need to leave free in the AG.
*
* The tree is ordered by [ag block, owner, offset]. This is a large key size,
* but it is the only way to enforce unique keys when a block can be owned by
* multiple files at any offset. There's no need to order/search by extent
* size for online updating/management of the tree. It is intended that most
* reverse lookups will be to find the owner(s) of a particular block, or to
* try to recover tree and file data from corrupt primary metadata.
*/
static struct xfs_btree_cur *
xfs_rmapbt_dup_cursor(
struct xfs_btree_cur *cur)
{
return xfs_rmapbt_init_cursor(cur->bc_mp, cur->bc_tp,
cur->bc_private.a.agbp, cur->bc_private.a.agno);
}
STATIC void
xfs_rmapbt_set_root(
struct xfs_btree_cur *cur,
union xfs_btree_ptr *ptr,
int inc)
{
struct xfs_buf *agbp = cur->bc_private.a.agbp;
struct xfs_agf *agf = XFS_BUF_TO_AGF(agbp);
xfs_agnumber_t seqno = be32_to_cpu(agf->agf_seqno);
int btnum = cur->bc_btnum;
struct xfs_perag *pag = xfs_perag_get(cur->bc_mp, seqno);
ASSERT(ptr->s != 0);
agf->agf_roots[btnum] = ptr->s;
be32_add_cpu(&agf->agf_levels[btnum], inc);
pag->pagf_levels[btnum] += inc;
xfs_perag_put(pag);
xfs_alloc_log_agf(cur->bc_tp, agbp, XFS_AGF_ROOTS | XFS_AGF_LEVELS);
}
STATIC int
xfs_rmapbt_alloc_block(
struct xfs_btree_cur *cur,
union xfs_btree_ptr *start,
union xfs_btree_ptr *new,
int *stat)
{
struct xfs_buf *agbp = cur->bc_private.a.agbp;
struct xfs_agf *agf = XFS_BUF_TO_AGF(agbp);
int error;
xfs_agblock_t bno;
/* Allocate the new block from the freelist. If we can't, give up. */
error = xfs_alloc_get_freelist(cur->bc_tp, cur->bc_private.a.agbp,
&bno, 1);
if (error)
return error;
trace_xfs_rmapbt_alloc_block(cur->bc_mp, cur->bc_private.a.agno,
bno, 1);
if (bno == NULLAGBLOCK) {
*stat = 0;
return 0;
}
xfs_extent_busy_reuse(cur->bc_mp, cur->bc_private.a.agno, bno, 1,
false);
xfs_trans_agbtree_delta(cur->bc_tp, 1);
new->s = cpu_to_be32(bno);
be32_add_cpu(&agf->agf_rmap_blocks, 1);
xfs_alloc_log_agf(cur->bc_tp, agbp, XFS_AGF_RMAP_BLOCKS);
xfs_ag_resv_rmapbt_alloc(cur->bc_mp, cur->bc_private.a.agno);
*stat = 1;
return 0;
}
STATIC int
xfs_rmapbt_free_block(
struct xfs_btree_cur *cur,
struct xfs_buf *bp)
{
struct xfs_buf *agbp = cur->bc_private.a.agbp;
struct xfs_agf *agf = XFS_BUF_TO_AGF(agbp);
xfs_agblock_t bno;
int error;
bno = xfs_daddr_to_agbno(cur->bc_mp, XFS_BUF_ADDR(bp));
trace_xfs_rmapbt_free_block(cur->bc_mp, cur->bc_private.a.agno,
bno, 1);
be32_add_cpu(&agf->agf_rmap_blocks, -1);
xfs_alloc_log_agf(cur->bc_tp, agbp, XFS_AGF_RMAP_BLOCKS);
error = xfs_alloc_put_freelist(cur->bc_tp, agbp, NULL, bno, 1);
if (error)
return error;
xfs_extent_busy_insert(cur->bc_tp, be32_to_cpu(agf->agf_seqno), bno, 1,
XFS_EXTENT_BUSY_SKIP_DISCARD);
xfs_trans_agbtree_delta(cur->bc_tp, -1);
xfs_ag_resv_rmapbt_free(cur->bc_mp, cur->bc_private.a.agno);
return 0;
}
STATIC int
xfs_rmapbt_get_minrecs(
struct xfs_btree_cur *cur,
int level)
{
return cur->bc_mp->m_rmap_mnr[level != 0];
}
STATIC int
xfs_rmapbt_get_maxrecs(
struct xfs_btree_cur *cur,
int level)
{
return cur->bc_mp->m_rmap_mxr[level != 0];
}
STATIC void
xfs_rmapbt_init_key_from_rec(
union xfs_btree_key *key,
union xfs_btree_rec *rec)
{
key->rmap.rm_startblock = rec->rmap.rm_startblock;
key->rmap.rm_owner = rec->rmap.rm_owner;
key->rmap.rm_offset = rec->rmap.rm_offset;
}
/*
* The high key for a reverse mapping record can be computed by shifting
* the startblock and offset to the highest value that would still map
* to that record. In practice this means that we add blockcount-1 to
* the startblock for all records, and if the record is for a data/attr
* fork mapping, we add blockcount-1 to the offset too.
*/
STATIC void
xfs_rmapbt_init_high_key_from_rec(
union xfs_btree_key *key,
union xfs_btree_rec *rec)
{
uint64_t off;
int adj;
adj = be32_to_cpu(rec->rmap.rm_blockcount) - 1;
key->rmap.rm_startblock = rec->rmap.rm_startblock;
be32_add_cpu(&key->rmap.rm_startblock, adj);
key->rmap.rm_owner = rec->rmap.rm_owner;
key->rmap.rm_offset = rec->rmap.rm_offset;
if (XFS_RMAP_NON_INODE_OWNER(be64_to_cpu(rec->rmap.rm_owner)) ||
XFS_RMAP_IS_BMBT_BLOCK(be64_to_cpu(rec->rmap.rm_offset)))
return;
off = be64_to_cpu(key->rmap.rm_offset);
off = (XFS_RMAP_OFF(off) + adj) | (off & ~XFS_RMAP_OFF_MASK);
key->rmap.rm_offset = cpu_to_be64(off);
}
STATIC void
xfs_rmapbt_init_rec_from_cur(
struct xfs_btree_cur *cur,
union xfs_btree_rec *rec)
{
rec->rmap.rm_startblock = cpu_to_be32(cur->bc_rec.r.rm_startblock);
rec->rmap.rm_blockcount = cpu_to_be32(cur->bc_rec.r.rm_blockcount);
rec->rmap.rm_owner = cpu_to_be64(cur->bc_rec.r.rm_owner);
rec->rmap.rm_offset = cpu_to_be64(
xfs_rmap_irec_offset_pack(&cur->bc_rec.r));
}
STATIC void
xfs_rmapbt_init_ptr_from_cur(
struct xfs_btree_cur *cur,
union xfs_btree_ptr *ptr)
{
struct xfs_agf *agf = XFS_BUF_TO_AGF(cur->bc_private.a.agbp);
ASSERT(cur->bc_private.a.agno == be32_to_cpu(agf->agf_seqno));
ptr->s = agf->agf_roots[cur->bc_btnum];
}
STATIC int64_t
xfs_rmapbt_key_diff(
struct xfs_btree_cur *cur,
union xfs_btree_key *key)
{
struct xfs_rmap_irec *rec = &cur->bc_rec.r;
struct xfs_rmap_key *kp = &key->rmap;
__u64 x, y;
int64_t d;
d = (int64_t)be32_to_cpu(kp->rm_startblock) - rec->rm_startblock;
if (d)
return d;
x = be64_to_cpu(kp->rm_owner);
y = rec->rm_owner;
if (x > y)
return 1;
else if (y > x)
return -1;
x = XFS_RMAP_OFF(be64_to_cpu(kp->rm_offset));
y = rec->rm_offset;
if (x > y)
return 1;
else if (y > x)
return -1;
return 0;
}
STATIC int64_t
xfs_rmapbt_diff_two_keys(
struct xfs_btree_cur *cur,
union xfs_btree_key *k1,
union xfs_btree_key *k2)
{
struct xfs_rmap_key *kp1 = &k1->rmap;
struct xfs_rmap_key *kp2 = &k2->rmap;
int64_t d;
__u64 x, y;
d = (int64_t)be32_to_cpu(kp1->rm_startblock) -
be32_to_cpu(kp2->rm_startblock);
if (d)
return d;
x = be64_to_cpu(kp1->rm_owner);
y = be64_to_cpu(kp2->rm_owner);
if (x > y)
return 1;
else if (y > x)
return -1;
x = XFS_RMAP_OFF(be64_to_cpu(kp1->rm_offset));
y = XFS_RMAP_OFF(be64_to_cpu(kp2->rm_offset));
if (x > y)
return 1;
else if (y > x)
return -1;
return 0;
}
static xfs_failaddr_t
xfs_rmapbt_verify(
struct xfs_buf *bp)
{
struct xfs_mount *mp = bp->b_mount;
struct xfs_btree_block *block = XFS_BUF_TO_BLOCK(bp);
struct xfs_perag *pag = bp->b_pag;
xfs_failaddr_t fa;
unsigned int level;
/*
* magic number and level verification
*
* During growfs operations, we can't verify the exact level or owner as
* the perag is not fully initialised and hence not attached to the
* buffer. In this case, check against the maximum tree depth.
*
* Similarly, during log recovery we will have a perag structure
* attached, but the agf information will not yet have been initialised
* from the on disk AGF. Again, we can only check against maximum limits
* in this case.
*/
if (!xfs_verify_magic(bp, block->bb_magic))
return __this_address;
if (!xfs_sb_version_hasrmapbt(&mp->m_sb))
return __this_address;
fa = xfs_btree_sblock_v5hdr_verify(bp);
if (fa)
return fa;
level = be16_to_cpu(block->bb_level);
if (pag && pag->pagf_init) {
if (level >= pag->pagf_levels[XFS_BTNUM_RMAPi])
return __this_address;
} else if (level >= mp->m_rmap_maxlevels)
return __this_address;
return xfs_btree_sblock_verify(bp, mp->m_rmap_mxr[level != 0]);
}
static void
xfs_rmapbt_read_verify(
struct xfs_buf *bp)
{
xfs_failaddr_t fa;
if (!xfs_btree_sblock_verify_crc(bp))
xfs_verifier_error(bp, -EFSBADCRC, __this_address);
else {
fa = xfs_rmapbt_verify(bp);
if (fa)
xfs_verifier_error(bp, -EFSCORRUPTED, fa);
}
if (bp->b_error)
trace_xfs_btree_corrupt(bp, _RET_IP_);
}
static void
xfs_rmapbt_write_verify(
struct xfs_buf *bp)
{
xfs_failaddr_t fa;
fa = xfs_rmapbt_verify(bp);
if (fa) {
trace_xfs_btree_corrupt(bp, _RET_IP_);
xfs_verifier_error(bp, -EFSCORRUPTED, fa);
return;
}
xfs_btree_sblock_calc_crc(bp);
}
const struct xfs_buf_ops xfs_rmapbt_buf_ops = {
.name = "xfs_rmapbt",
.magic = { 0, cpu_to_be32(XFS_RMAP_CRC_MAGIC) },
.verify_read = xfs_rmapbt_read_verify,
.verify_write = xfs_rmapbt_write_verify,
.verify_struct = xfs_rmapbt_verify,
};
STATIC int
xfs_rmapbt_keys_inorder(
struct xfs_btree_cur *cur,
union xfs_btree_key *k1,
union xfs_btree_key *k2)
{
uint32_t x;
uint32_t y;
uint64_t a;
uint64_t b;
x = be32_to_cpu(k1->rmap.rm_startblock);
y = be32_to_cpu(k2->rmap.rm_startblock);
if (x < y)
return 1;
else if (x > y)
return 0;
a = be64_to_cpu(k1->rmap.rm_owner);
b = be64_to_cpu(k2->rmap.rm_owner);
if (a < b)
return 1;
else if (a > b)
return 0;
a = XFS_RMAP_OFF(be64_to_cpu(k1->rmap.rm_offset));
b = XFS_RMAP_OFF(be64_to_cpu(k2->rmap.rm_offset));
if (a <= b)
return 1;
return 0;
}
STATIC int
xfs_rmapbt_recs_inorder(
struct xfs_btree_cur *cur,
union xfs_btree_rec *r1,
union xfs_btree_rec *r2)
{
uint32_t x;
uint32_t y;
uint64_t a;
uint64_t b;
x = be32_to_cpu(r1->rmap.rm_startblock);
y = be32_to_cpu(r2->rmap.rm_startblock);
if (x < y)
return 1;
else if (x > y)
return 0;
a = be64_to_cpu(r1->rmap.rm_owner);
b = be64_to_cpu(r2->rmap.rm_owner);
if (a < b)
return 1;
else if (a > b)
return 0;
a = XFS_RMAP_OFF(be64_to_cpu(r1->rmap.rm_offset));
b = XFS_RMAP_OFF(be64_to_cpu(r2->rmap.rm_offset));
if (a <= b)
return 1;
return 0;
}
static const struct xfs_btree_ops xfs_rmapbt_ops = {
.rec_len = sizeof(struct xfs_rmap_rec),
.key_len = 2 * sizeof(struct xfs_rmap_key),
.dup_cursor = xfs_rmapbt_dup_cursor,
.set_root = xfs_rmapbt_set_root,
.alloc_block = xfs_rmapbt_alloc_block,
.free_block = xfs_rmapbt_free_block,
.get_minrecs = xfs_rmapbt_get_minrecs,
.get_maxrecs = xfs_rmapbt_get_maxrecs,
.init_key_from_rec = xfs_rmapbt_init_key_from_rec,
.init_high_key_from_rec = xfs_rmapbt_init_high_key_from_rec,
.init_rec_from_cur = xfs_rmapbt_init_rec_from_cur,
.init_ptr_from_cur = xfs_rmapbt_init_ptr_from_cur,
.key_diff = xfs_rmapbt_key_diff,
.buf_ops = &xfs_rmapbt_buf_ops,
.diff_two_keys = xfs_rmapbt_diff_two_keys,
.keys_inorder = xfs_rmapbt_keys_inorder,
.recs_inorder = xfs_rmapbt_recs_inorder,
};
/*
* Allocate a new allocation btree cursor.
*/
struct xfs_btree_cur *
xfs_rmapbt_init_cursor(
struct xfs_mount *mp,
struct xfs_trans *tp,
struct xfs_buf *agbp,
xfs_agnumber_t agno)
{
struct xfs_agf *agf = XFS_BUF_TO_AGF(agbp);
struct xfs_btree_cur *cur;
cur = kmem_zone_zalloc(xfs_btree_cur_zone, KM_NOFS);
cur->bc_tp = tp;
cur->bc_mp = mp;
/* Overlapping btree; 2 keys per pointer. */
cur->bc_btnum = XFS_BTNUM_RMAP;
cur->bc_flags = XFS_BTREE_CRC_BLOCKS | XFS_BTREE_OVERLAPPING;
cur->bc_blocklog = mp->m_sb.sb_blocklog;
cur->bc_ops = &xfs_rmapbt_ops;
cur->bc_nlevels = be32_to_cpu(agf->agf_levels[XFS_BTNUM_RMAP]);
cur->bc_statoff = XFS_STATS_CALC_INDEX(xs_rmap_2);
cur->bc_private.a.agbp = agbp;
cur->bc_private.a.agno = agno;
return cur;
}
/*
* Calculate number of records in an rmap btree block.
*/
int
xfs_rmapbt_maxrecs(
int blocklen,
int leaf)
{
blocklen -= XFS_RMAP_BLOCK_LEN;
if (leaf)
return blocklen / sizeof(struct xfs_rmap_rec);
return blocklen /
(2 * sizeof(struct xfs_rmap_key) + sizeof(xfs_rmap_ptr_t));
}
/* Compute the maximum height of an rmap btree. */
void
xfs_rmapbt_compute_maxlevels(
struct xfs_mount *mp)
{
/*
* On a non-reflink filesystem, the maximum number of rmap
* records is the number of blocks in the AG, hence the max
* rmapbt height is log_$maxrecs($agblocks). However, with
* reflink each AG block can have up to 2^32 (per the refcount
* record format) owners, which means that theoretically we
* could face up to 2^64 rmap records.
*
* That effectively means that the max rmapbt height must be
* XFS_BTREE_MAXLEVELS. "Fortunately" we'll run out of AG
* blocks to feed the rmapbt long before the rmapbt reaches
* maximum height. The reflink code uses ag_resv_critical to
* disallow reflinking when less than 10% of the per-AG metadata
* block reservation since the fallback is a regular file copy.
*/
if (xfs_sb_version_hasreflink(&mp->m_sb))
mp->m_rmap_maxlevels = XFS_BTREE_MAXLEVELS;
else
mp->m_rmap_maxlevels = xfs_btree_compute_maxlevels(
mp->m_rmap_mnr, mp->m_sb.sb_agblocks);
}
/* Calculate the refcount btree size for some records. */
xfs_extlen_t
xfs_rmapbt_calc_size(
struct xfs_mount *mp,
unsigned long long len)
{
return xfs_btree_calc_size(mp->m_rmap_mnr, len);
}
/*
* Calculate the maximum refcount btree size.
*/
xfs_extlen_t
xfs_rmapbt_max_size(
struct xfs_mount *mp,
xfs_agblock_t agblocks)
{
/* Bail out if we're uninitialized, which can happen in mkfs. */
if (mp->m_rmap_mxr[0] == 0)
return 0;
return xfs_rmapbt_calc_size(mp, agblocks);
}
/*
* Figure out how many blocks to reserve and how many are used by this btree.
*/
int
xfs_rmapbt_calc_reserves(
struct xfs_mount *mp,
struct xfs_trans *tp,
xfs_agnumber_t agno,
xfs_extlen_t *ask,
xfs_extlen_t *used)
{
struct xfs_buf *agbp;
struct xfs_agf *agf;
xfs_agblock_t agblocks;
xfs_extlen_t tree_len;
int error;
if (!xfs_sb_version_hasrmapbt(&mp->m_sb))
return 0;
error = xfs_alloc_read_agf(mp, tp, agno, 0, &agbp);
if (error)
return error;
agf = XFS_BUF_TO_AGF(agbp);
agblocks = be32_to_cpu(agf->agf_length);
tree_len = be32_to_cpu(agf->agf_rmap_blocks);
xfs_trans_brelse(tp, agbp);
/*
* The log is permanently allocated, so the space it occupies will
* never be available for the kinds of things that would require btree
* expansion. We therefore can pretend the space isn't there.
*/
if (mp->m_sb.sb_logstart &&
XFS_FSB_TO_AGNO(mp, mp->m_sb.sb_logstart) == agno)
agblocks -= mp->m_sb.sb_logblocks;
/* Reserve 1% of the AG or enough for 1 block per record. */
*ask += max(agblocks / 100, xfs_rmapbt_max_size(mp, agblocks));
*used += tree_len;
return error;
}
