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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (c) 2000-2003,2005 Silicon Graphics, Inc.
* Copyright (C) 2010 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_mount.h"
#include "xfs_da_format.h"
#include "xfs_da_btree.h"
#include "xfs_inode.h"
#include "xfs_bmap_btree.h"
#include "xfs_quota.h"
#include "xfs_trans.h"
#include "xfs_qm.h"
#include "xfs_trans_space.h"
#define _ALLOC true
#define _FREE false
/*
* A buffer has a format structure overhead in the log in addition
* to the data, so we need to take this into account when reserving
* space in a transaction for a buffer. Round the space required up
* to a multiple of 128 bytes so that we don't change the historical
* reservation that has been used for this overhead.
*/
STATIC uint
xfs_buf_log_overhead(void)
{
return round_up(sizeof(struct xlog_op_header) +
sizeof(struct xfs_buf_log_format), 128);
}
/*
* Calculate out transaction log reservation per item in bytes.
*
* The nbufs argument is used to indicate the number of items that
* will be changed in a transaction. size is used to tell how many
* bytes should be reserved per item.
*/
STATIC uint
xfs_calc_buf_res(
uint nbufs,
uint size)
{
return nbufs * (size + xfs_buf_log_overhead());
}
/*
* Per-extent log reservation for the btree changes involved in freeing or
* allocating an extent. In classic XFS there were two trees that will be
* modified (bnobt + cntbt). With rmap enabled, there are three trees
* (rmapbt). With reflink, there are four trees (refcountbt). The number of
* blocks reserved is based on the formula:
*
* num trees * ((2 blocks/level * max depth) - 1)
*
* Keep in mind that max depth is calculated separately for each type of tree.
*/
uint
xfs_allocfree_log_count(
struct xfs_mount *mp,
uint num_ops)
{
uint blocks;
blocks = num_ops * 2 * (2 * mp->m_ag_maxlevels - 1);
if (xfs_sb_version_hasrmapbt(&mp->m_sb))
blocks += num_ops * (2 * mp->m_rmap_maxlevels - 1);
if (xfs_sb_version_hasreflink(&mp->m_sb))
blocks += num_ops * (2 * mp->m_refc_maxlevels - 1);
return blocks;
}
/*
* Logging inodes is really tricksy. They are logged in memory format,
* which means that what we write into the log doesn't directly translate into
* the amount of space they use on disk.
*
* Case in point - btree format forks in memory format use more space than the
* on-disk format. In memory, the buffer contains a normal btree block header so
* the btree code can treat it as though it is just another generic buffer.
* However, when we write it to the inode fork, we don't write all of this
* header as it isn't needed. e.g. the root is only ever in the inode, so
* there's no need for sibling pointers which would waste 16 bytes of space.
*
* Hence when we have an inode with a maximally sized btree format fork, then
* amount of information we actually log is greater than the size of the inode
* on disk. Hence we need an inode reservation function that calculates all this
* correctly. So, we log:
*
* - 4 log op headers for object
* - for the ilf, the inode core and 2 forks
* - inode log format object
* - the inode core
* - two inode forks containing bmap btree root blocks.
* - the btree data contained by both forks will fit into the inode size,
* hence when combined with the inode core above, we have a total of the
* actual inode size.
* - the BMBT headers need to be accounted separately, as they are
* additional to the records and pointers that fit inside the inode
* forks.
*/
STATIC uint
xfs_calc_inode_res(
struct xfs_mount *mp,
uint ninodes)
{
return ninodes *
(4 * sizeof(struct xlog_op_header) +
sizeof(struct xfs_inode_log_format) +
mp->m_sb.sb_inodesize +
2 * XFS_BMBT_BLOCK_LEN(mp));
}
/*
* Inode btree record insertion/removal modifies the inode btree and free space
* btrees (since the inobt does not use the agfl). This requires the following
* reservation:
*
* the inode btree: max depth * blocksize
* the allocation btrees: 2 trees * (max depth - 1) * block size
*
* The caller must account for SB and AG header modifications, etc.
*/
STATIC uint
xfs_calc_inobt_res(
struct xfs_mount *mp)
{
return xfs_calc_buf_res(M_IGEO(mp)->inobt_maxlevels,
XFS_FSB_TO_B(mp, 1)) +
xfs_calc_buf_res(xfs_allocfree_log_count(mp, 1),
XFS_FSB_TO_B(mp, 1));
}
/*
* The free inode btree is a conditional feature. The behavior differs slightly
* from that of the traditional inode btree in that the finobt tracks records
* for inode chunks with at least one free inode. A record can be removed from
* the tree during individual inode allocation. Therefore the finobt
* reservation is unconditional for both the inode chunk allocation and
* individual inode allocation (modify) cases.
*
* Behavior aside, the reservation for finobt modification is equivalent to the
* traditional inobt: cover a full finobt shape change plus block allocation.
*/
STATIC uint
xfs_calc_finobt_res(
struct xfs_mount *mp)
{
if (!xfs_sb_version_hasfinobt(&mp->m_sb))
return 0;
return xfs_calc_inobt_res(mp);
}
/*
* Calculate the reservation required to allocate or free an inode chunk. This
* includes:
*
* the allocation btrees: 2 trees * (max depth - 1) * block size
* the inode chunk: m_ino_geo.ialloc_blks * N
*
* The size N of the inode chunk reservation depends on whether it is for
* allocation or free and which type of create transaction is in use. An inode
* chunk free always invalidates the buffers and only requires reservation for
* headers (N == 0). An inode chunk allocation requires a chunk sized
* reservation on v4 and older superblocks to initialize the chunk. No chunk
* reservation is required for allocation on v5 supers, which use ordered
* buffers to initialize.
*/
STATIC uint
xfs_calc_inode_chunk_res(
struct xfs_mount *mp,
bool alloc)
{
uint res, size = 0;
res = xfs_calc_buf_res(xfs_allocfree_log_count(mp, 1),
XFS_FSB_TO_B(mp, 1));
if (alloc) {
/* icreate tx uses ordered buffers */
if (xfs_sb_version_has_v3inode(&mp->m_sb))
return res;
size = XFS_FSB_TO_B(mp, 1);
}
res += xfs_calc_buf_res(M_IGEO(mp)->ialloc_blks, size);
return res;
}
/*
* Per-extent log reservation for the btree changes involved in freeing or
* allocating a realtime extent. We have to be able to log as many rtbitmap
* blocks as needed to mark inuse MAXEXTLEN blocks' worth of realtime extents,
* as well as the realtime summary block.
*/
static unsigned int
xfs_rtalloc_log_count(
struct xfs_mount *mp,
unsigned int num_ops)
{
unsigned int blksz = XFS_FSB_TO_B(mp, 1);
unsigned int rtbmp_bytes;
rtbmp_bytes = (MAXEXTLEN / mp->m_sb.sb_rextsize) / NBBY;
return (howmany(rtbmp_bytes, blksz) + 1) * num_ops;
}
/*
* Various log reservation values.
*
* These are based on the size of the file system block because that is what
* most transactions manipulate. Each adds in an additional 128 bytes per
* item logged to try to account for the overhead of the transaction mechanism.
*
* Note: Most of the reservations underestimate the number of allocation
* groups into which they could free extents in the xfs_defer_finish() call.
* This is because the number in the worst case is quite high and quite
* unusual. In order to fix this we need to change xfs_defer_finish() to free
* extents in only a single AG at a time. This will require changes to the
* EFI code as well, however, so that the EFI for the extents not freed is
* logged again in each transaction. See SGI PV #261917.
*
* Reservation functions here avoid a huge stack in xfs_trans_init due to
* register overflow from temporaries in the calculations.
*/
/*
* In a write transaction we can allocate a maximum of 2
* extents. This gives (t1):
* the inode getting the new extents: inode size
* the inode's bmap btree: max depth * block size
* the agfs of the ags from which the extents are allocated: 2 * sector
* the superblock free block counter: sector size
* the allocation btrees: 2 exts * 2 trees * (2 * max depth - 1) * block size
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