path: root/fs/xfs/xfs_inode_item.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (c) 2000-2002,2005 Silicon Graphics, 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_inode.h"
#include "xfs_trans.h"
#include "xfs_inode_item.h"
#include "xfs_trace.h"
#include "xfs_trans_priv.h"
#include "xfs_buf_item.h"
#include "xfs_log.h"
#include "xfs_log_priv.h"
#include "xfs_error.h"
#include "xfs_rtbitmap.h"

#include <linux/iversion.h>

struct kmem_cache	*xfs_ili_cache;		/* inode log item */

static inline struct xfs_inode_log_item *INODE_ITEM(struct xfs_log_item *lip)
{
	return container_of(lip, struct xfs_inode_log_item, ili_item);
}

static uint64_t
xfs_inode_item_sort(
	struct xfs_log_item	*lip)
{
	return INODE_ITEM(lip)->ili_inode->i_ino;
}

/*
 * Prior to finally logging the inode, we have to ensure that all the
 * per-modification inode state changes are applied. This includes VFS inode
 * state updates, format conversions, verifier state synchronisation and
 * ensuring the inode buffer remains in memory whilst the inode is dirty.
 *
 * We have to be careful when we grab the inode cluster buffer due to lock
 * ordering constraints. The unlinked inode modifications (xfs_iunlink_item)
 * require AGI -> inode cluster buffer lock order. The inode cluster buffer is
 * not locked until ->precommit, so it happens after everything else has been
 * modified.
 *
 * Further, we have AGI -> AGF lock ordering, and with O_TMPFILE handling we
 * have AGI -> AGF -> iunlink item -> inode cluster buffer lock order. Hence we
 * cannot safely lock the inode cluster buffer in xfs_trans_log_inode() because
 * it can be called on a inode (e.g. via bumplink/droplink) before we take the
 * AGF lock modifying directory blocks.
 *
 * Rather than force a complete rework of all the transactions to call
 * xfs_trans_log_inode() once and once only at the end of every transaction, we
 * move the pinning of the inode cluster buffer to a ->precommit operation. This
 * matches how the xfs_iunlink_item locks the inode cluster buffer, and it
 * ensures that the inode cluster buffer locking is always done last in a
 * transaction. i.e. we ensure the lock order is always AGI -> AGF -> inode
 * cluster buffer.
 *
 * If we return the inode number as the precommit sort key then we'll also
 * guarantee that the order all inode cluster buffer locking is the same all the
 * inodes and unlink items in the transaction.
 */
static int
xfs_inode_item_precommit(
	struct xfs_trans	*tp,
	struct xfs_log_item	*lip)
{
	struct xfs_inode_log_item *iip = INODE_ITEM(lip);
	struct xfs_inode	*ip = iip->ili_inode;
	struct inode		*inode = VFS_I(ip);
	unsigned int		flags = iip->ili_dirty_flags;

	/*
	 * Don't bother with i_lock for the I_DIRTY_TIME check here, as races
	 * don't matter - we either will need an extra transaction in 24 hours
	 * to log the timestamps, or will clear already cleared fields in the
	 * worst case.
	 */
	if (inode->i_state & I_DIRTY_TIME) {
		spin_lock(&inode->i_lock);
		inode->i_state &= ~I_DIRTY_TIME;
		spin_unlock(&inode->i_lock);
	}

	/*
	 * If we're updating the inode core or the timestamps and it's possible
	 * to upgrade this inode to bigtime format, do so now.
	 */
	if ((flags & (XFS_ILOG_CORE | XFS_ILOG_TIMESTAMP)) &&
	    xfs_has_bigtime(ip->i_mount) &&
	    !xfs_inode_has_bigtime(ip)) {
		ip->i_diflags2 |= XFS_DIFLAG2_BIGTIME;
		flags |= XFS_ILOG_CORE;
	}

	/*
	 * Inode verifiers do not check that the extent size hint is an integer
	 * multiple of the rt extent size on a directory with both rtinherit
	 * and extszinherit flags set.  If we're logging a directory that is
	 * misconfigured in this way, clear the hint.
	 */
	if ((ip->i_diflags & XFS_DIFLAG_RTINHERIT) &&
	    (ip->i_diflags & XFS_DIFLAG_EXTSZINHERIT) &&
	    xfs_extlen_to_rtxmod(ip->i_mount, ip->i_extsize) > 0) {
		ip->i_diflags &= ~(XFS_DIFLAG_EXTSIZE |
				   XFS_DIFLAG_EXTSZINHERIT);
		ip->i_extsize = 0;
		flags |= XFS_ILOG_CORE;
	}

	/*
	 * Record the specific change for fdatasync optimisation. This allows
	 * fdatasync to skip log forces for inodes that are only timestamp
	 * dirty. Once we've processed the XFS_ILOG_IVERSION flag, convert it
	 * to XFS_ILOG_CORE so that the actual on-disk dirty tracking
	 * (ili_fields) correctly tracks that the version has changed.
	 */
	spin_lock(&iip->ili_lock);
	iip->ili_fsync_fields |= (flags & ~XFS_ILOG_IVERSION);
	if (flags & XFS_ILOG_IVERSION)
		flags = ((flags & ~XFS_ILOG_IVERSION) | XFS_ILOG_CORE);

	if (!iip->ili_item.li_buf) {
		struct xfs_buf	*bp;
		int		error;

		/*
		 * We hold the ILOCK here, so this inode is not going to be
		 * flushed while we are here. Further, because there is no
		 * buffer attached to the item, we know that there is no IO in
		 * progress, so nothing will clear the ili_fields while we read
		 * in the buffer. Hence we can safely drop the spin lock and
		 * read the buffer knowing that the state will not change from
		 * here.
		 */
		spin_unlock(&iip->ili_lock);
		error = xfs_imap_to_bp(ip->i_mount, tp, &ip->i_imap, &bp);
		if (error)
			return error;

		/*
		 * We need an explicit buffer reference for the log item but
		 * don't want the buffer to remain attached to the transaction.
		 * Hold the buffer but release the transaction reference once
		 * we've attached the inode log item to the buffer log item
		 * list.
		 */
		xfs_buf_hold(bp);
		spin_lock(&iip->ili_lock);
		iip->ili_item.li_buf = bp;
		bp->b_flags |= _XBF_INODES;
		list_add_tail(&iip->ili_item.