path: root/fs/xfs/libxfs/xfs_exchmaps.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright (c) 2020-2024 Oracle.  All Rights Reserved.
 * Author: Darrick J. Wong <djwong@kernel.org>
 */
#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_defer.h"
#include "xfs_inode.h"
#include "xfs_trans.h"
#include "xfs_bmap.h"
#include "xfs_icache.h"
#include "xfs_quota.h"
#include "xfs_exchmaps.h"
#include "xfs_trace.h"
#include "xfs_bmap_btree.h"
#include "xfs_trans_space.h"
#include "xfs_error.h"
#include "xfs_errortag.h"
#include "xfs_health.h"
#include "xfs_exchmaps_item.h"
#include "xfs_da_format.h"
#include "xfs_da_btree.h"
#include "xfs_attr_leaf.h"
#include "xfs_attr.h"
#include "xfs_dir2_priv.h"
#include "xfs_dir2.h"
#include "xfs_symlink_remote.h"

struct kmem_cache	*xfs_exchmaps_intent_cache;

/* bmbt mappings adjacent to a pair of records. */
struct xfs_exchmaps_adjacent {
	struct xfs_bmbt_irec		left1;
	struct xfs_bmbt_irec		right1;
	struct xfs_bmbt_irec		left2;
	struct xfs_bmbt_irec		right2;
};

#define ADJACENT_INIT { \
	.left1  = { .br_startblock = HOLESTARTBLOCK }, \
	.right1 = { .br_startblock = HOLESTARTBLOCK }, \
	.left2  = { .br_startblock = HOLESTARTBLOCK }, \
	.right2 = { .br_startblock = HOLESTARTBLOCK }, \
}

/* Information to reset reflink flag / CoW fork state after an exchange. */

/*
 * If the reflink flag is set on either inode, make sure it has an incore CoW
 * fork, since all reflink inodes must have them.  If there's a CoW fork and it
 * has mappings in it, make sure the inodes are tagged appropriately so that
 * speculative preallocations can be GC'd if we run low of space.
 */
static inline void
xfs_exchmaps_ensure_cowfork(
	struct xfs_inode	*ip)
{
	struct xfs_ifork	*cfork;

	if (xfs_is_reflink_inode(ip))
		xfs_ifork_init_cow(ip);

	cfork = xfs_ifork_ptr(ip, XFS_COW_FORK);
	if (!cfork)
		return;
	if (cfork->if_bytes > 0)
		xfs_inode_set_cowblocks_tag(ip);
	else
		xfs_inode_clear_cowblocks_tag(ip);
}

/*
 * Adjust the on-disk inode size upwards if needed so that we never add
 * mappings into the file past EOF.  This is crucial so that log recovery won't
 * get confused by the sudden appearance of post-eof mappings.
 */
STATIC void
xfs_exchmaps_update_size(
	struct xfs_trans	*tp,
	struct xfs_inode	*ip,
	struct xfs_bmbt_irec	*imap,
	xfs_fsize_t		new_isize)
{
	struct xfs_mount	*mp = tp->t_mountp;
	xfs_fsize_t		len;

	if (new_isize < 0)
		return;

	len = min(XFS_FSB_TO_B(mp, imap->br_startoff + imap->br_blockcount),
		  new_isize);

	if (len <= ip->i_disk_size)
		return;

	trace_xfs_exchmaps_update_inode_size(ip, len);

	ip->i_disk_size = len;
	xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
}

/* Advance the incore state tracking after exchanging a mapping. */
static inline void
xmi_advance(
	struct xfs_exchmaps_intent	*xmi,
	const struct xfs_bmbt_irec	*irec)
{
	xmi->xmi_startoff1 += irec->br_blockcount;
	xmi->xmi_startoff2 += irec->br_blockcount;
	xmi->xmi_blockcount -= irec->br_blockcount;
}

/* Do we still have more mappings to exchange? */
static inline bool
xmi_has_more_exchange_work(const struct xfs_exchmaps_intent *xmi)
{
	return xmi->xmi_blockcount > 0;
}

/* Do we have post-operation cleanups to perform? */
static inline bool
xmi_has_postop_work(const struct xfs_exchmaps_intent *xmi)
{
	return xmi->xmi_flags & (XFS_EXCHMAPS_CLEAR_INO1_REFLINK |
				 XFS_EXCHMAPS_CLEAR_INO2_REFLINK |
				 __XFS_EXCHMAPS_INO2_SHORTFORM);
}

/* Check all mappings to make sure we can actually exchange them. */
int
xfs_exchmaps_check_forks(
	struct xfs_mount		*mp,
	const struct xfs_exchmaps_req	*req)
{
	struct xfs_ifork		*ifp1, *ifp2;
	int				whichfork = xfs_exchmaps_reqfork(req);

	/* No fork? */
	ifp1 = xfs_ifork_ptr(req