Ejemplo n.º 1
0
/*
 * Unmap a range of blocks from a file, then map other blocks into the hole.
 * The range to unmap is (destoff : destoff + srcioff + irec->br_blockcount).
 * The extent irec is mapped into dest at irec->br_startoff.
 */
STATIC int
xfs_reflink_remap_extent(
	struct xfs_inode	*ip,
	struct xfs_bmbt_irec	*irec,
	xfs_fileoff_t		destoff,
	xfs_off_t		new_isize)
{
	struct xfs_mount	*mp = ip->i_mount;
	bool			real_extent = xfs_bmap_is_real_extent(irec);
	struct xfs_trans	*tp;
	xfs_fsblock_t		firstfsb;
	unsigned int		resblks;
	struct xfs_defer_ops	dfops;
	struct xfs_bmbt_irec	uirec;
	xfs_filblks_t		rlen;
	xfs_filblks_t		unmap_len;
	xfs_off_t		newlen;
	int			error;

	unmap_len = irec->br_startoff + irec->br_blockcount - destoff;
	trace_xfs_reflink_punch_range(ip, destoff, unmap_len);

	/* No reflinking if we're low on space */
	if (real_extent) {
		error = xfs_reflink_ag_has_free_space(mp,
				XFS_FSB_TO_AGNO(mp, irec->br_startblock));
		if (error)
			goto out;
	}

	/* Start a rolling transaction to switch the mappings */
	resblks = XFS_EXTENTADD_SPACE_RES(ip->i_mount, XFS_DATA_FORK);
	error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write, resblks, 0, 0, &tp);
	if (error)
		goto out;

	xfs_ilock(ip, XFS_ILOCK_EXCL);
	xfs_trans_ijoin(tp, ip, 0);

	/* If we're not just clearing space, then do we have enough quota? */
	if (real_extent) {
		error = xfs_trans_reserve_quota_nblks(tp, ip,
				irec->br_blockcount, 0, XFS_QMOPT_RES_REGBLKS);
		if (error)
			goto out_cancel;
	}

	trace_xfs_reflink_remap(ip, irec->br_startoff,
				irec->br_blockcount, irec->br_startblock);

	/* Unmap the old blocks in the data fork. */
	rlen = unmap_len;
	while (rlen) {
		xfs_defer_init(&dfops, &firstfsb);
		error = __xfs_bunmapi(tp, ip, destoff, &rlen, 0, 1,
				&firstfsb, &dfops);
		if (error)
			goto out_defer;

		/*
		 * Trim the extent to whatever got unmapped.
		 * Remember, bunmapi works backwards.
		 */
		uirec.br_startblock = irec->br_startblock + rlen;
		uirec.br_startoff = irec->br_startoff + rlen;
		uirec.br_blockcount = unmap_len - rlen;
		unmap_len = rlen;

		/* If this isn't a real mapping, we're done. */
		if (!real_extent || uirec.br_blockcount == 0)
			goto next_extent;

		trace_xfs_reflink_remap(ip, uirec.br_startoff,
				uirec.br_blockcount, uirec.br_startblock);

		/* Update the refcount tree */
		error = xfs_refcount_increase_extent(mp, &dfops, &uirec);
		if (error)
			goto out_defer;

		/* Map the new blocks into the data fork. */
		error = xfs_bmap_map_extent(mp, &dfops, ip, &uirec);
		if (error)
			goto out_defer;

		/* Update quota accounting. */
		xfs_trans_mod_dquot_byino(tp, ip, XFS_TRANS_DQ_BCOUNT,
				uirec.br_blockcount);

		/* Update dest isize if needed. */
		newlen = XFS_FSB_TO_B(mp,
				uirec.br_startoff + uirec.br_blockcount);
		newlen = min_t(xfs_off_t, newlen, new_isize);
		if (newlen > i_size_read(VFS_I(ip))) {
			trace_xfs_reflink_update_inode_size(ip, newlen);
			i_size_write(VFS_I(ip), newlen);
			ip->i_d.di_size = newlen;
			xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
		}

next_extent:
		/* Process all the deferred stuff. */
		xfs_defer_ijoin(&dfops, ip);
		error = xfs_defer_finish(&tp, &dfops);
		if (error)
			goto out_defer;
	}

	error = xfs_trans_commit(tp);
	xfs_iunlock(ip, XFS_ILOCK_EXCL);
	if (error)
		goto out;
	return 0;

out_defer:
	xfs_defer_cancel(&dfops);
out_cancel:
	xfs_trans_cancel(tp);
	xfs_iunlock(ip, XFS_ILOCK_EXCL);
out:
	trace_xfs_reflink_remap_extent_error(ip, error, _RET_IP_);
	return error;
}
Ejemplo n.º 2
0
/*
 * Remap parts of a file's data fork after a successful CoW.
 */
int
xfs_reflink_end_cow(
	struct xfs_inode		*ip,
	xfs_off_t			offset,
	xfs_off_t			count)
{
	struct xfs_ifork		*ifp = XFS_IFORK_PTR(ip, XFS_COW_FORK);
	struct xfs_bmbt_irec		got, del;
	struct xfs_trans		*tp;
	xfs_fileoff_t			offset_fsb;
	xfs_fileoff_t			end_fsb;
	xfs_fsblock_t			firstfsb;
	struct xfs_defer_ops		dfops;
	int				error;
	unsigned int			resblks;
	xfs_filblks_t			rlen;
	xfs_extnum_t			idx;

	trace_xfs_reflink_end_cow(ip, offset, count);

	/* No COW extents?  That's easy! */
	if (ifp->if_bytes == 0)
		return 0;

	offset_fsb = XFS_B_TO_FSBT(ip->i_mount, offset);
	end_fsb = XFS_B_TO_FSB(ip->i_mount, offset + count);

	/*
	 * Start a rolling transaction to switch the mappings.  We're
	 * unlikely ever to have to remap 16T worth of single-block
	 * extents, so just cap the worst case extent count to 2^32-1.
	 * Stick a warning in just in case, and avoid 64-bit division.
	 */
	BUILD_BUG_ON(MAX_RW_COUNT > UINT_MAX);
	if (end_fsb - offset_fsb > UINT_MAX) {
		error = -EFSCORRUPTED;
		xfs_force_shutdown(ip->i_mount, SHUTDOWN_CORRUPT_INCORE);
		ASSERT(0);
		goto out;
	}
	resblks = XFS_NEXTENTADD_SPACE_RES(ip->i_mount,
			(unsigned int)(end_fsb - offset_fsb),
			XFS_DATA_FORK);
	error = xfs_trans_alloc(ip->i_mount, &M_RES(ip->i_mount)->tr_write,
			resblks, 0, 0, &tp);
	if (error)
		goto out;

	xfs_ilock(ip, XFS_ILOCK_EXCL);
	xfs_trans_ijoin(tp, ip, 0);

	/* If there is a hole at end_fsb - 1 go to the previous extent */
	if (!xfs_iext_lookup_extent(ip, ifp, end_fsb - 1, &idx, &got) ||
	    got.br_startoff > end_fsb) {
		/*
		 * In case of racing, overlapping AIO writes no COW extents
		 * might be left by the time I/O completes for the loser of
		 * the race.  In that case we are done.
		 */
		if (idx <= 0)
			goto out_cancel;
		xfs_iext_get_extent(ifp, --idx, &got);
	}

	/* Walk backwards until we're out of the I/O range... */
	while (got.br_startoff + got.br_blockcount > offset_fsb) {
		del = got;
		xfs_trim_extent(&del, offset_fsb, end_fsb - offset_fsb);

		/* Extent delete may have bumped idx forward */
		if (!del.br_blockcount) {
			idx--;
			goto next_extent;
		}

		ASSERT(!isnullstartblock(got.br_startblock));

		/*
		 * Don't remap unwritten extents; these are
		 * speculatively preallocated CoW extents that have been
		 * allocated but have not yet been involved in a write.
		 */
		if (got.br_state == XFS_EXT_UNWRITTEN) {
			idx--;
			goto next_extent;
		}

		/* Unmap the old blocks in the data fork. */
		xfs_defer_init(&dfops, &firstfsb);
		rlen = del.br_blockcount;
		error = __xfs_bunmapi(tp, ip, del.br_startoff, &rlen, 0, 1,
				&firstfsb, &dfops);
		if (error)
			goto out_defer;

		/* Trim the extent to whatever got unmapped. */
		if (rlen) {
			xfs_trim_extent(&del, del.br_startoff + rlen,
				del.br_blockcount - rlen);
		}
		trace_xfs_reflink_cow_remap(ip, &del);

		/* Free the CoW orphan record. */
		error = xfs_refcount_free_cow_extent(tp->t_mountp, &dfops,
				del.br_startblock, del.br_blockcount);
		if (error)
			goto out_defer;

		/* Map the new blocks into the data fork. */
		error = xfs_bmap_map_extent(tp->t_mountp, &dfops, ip, &del);
		if (error)
			goto out_defer;

		/* Remove the mapping from the CoW fork. */
		xfs_bmap_del_extent_cow(ip, &idx, &got, &del);

		xfs_defer_ijoin(&dfops, ip);
		error = xfs_defer_finish(&tp, &dfops);
		if (error)
			goto out_defer;
next_extent:
		if (!xfs_iext_get_extent(ifp, idx, &got))
			break;
	}

	error = xfs_trans_commit(tp);
	xfs_iunlock(ip, XFS_ILOCK_EXCL);
	if (error)
		goto out;
	return 0;

out_defer:
	xfs_defer_cancel(&dfops);
out_cancel:
	xfs_trans_cancel(tp);
	xfs_iunlock(ip, XFS_ILOCK_EXCL);
out:
	trace_xfs_reflink_end_cow_error(ip, error, _RET_IP_);
	return error;
}
Ejemplo n.º 3
0
/*
 * Remap part of the CoW fork into the data fork.
 *
 * We aim to remap the range starting at @offset_fsb and ending at @end_fsb
 * into the data fork; this function will remap what it can (at the end of the
 * range) and update @end_fsb appropriately.  Each remap gets its own
 * transaction because we can end up merging and splitting bmbt blocks for
 * every remap operation and we'd like to keep the block reservation
 * requirements as low as possible.
 */
STATIC int
xfs_reflink_end_cow_extent(
	struct xfs_inode	*ip,
	xfs_fileoff_t		offset_fsb,
	xfs_fileoff_t		*end_fsb)
{
	struct xfs_bmbt_irec	got, del;
	struct xfs_iext_cursor	icur;
	struct xfs_mount	*mp = ip->i_mount;
	struct xfs_trans	*tp;
	struct xfs_ifork	*ifp = XFS_IFORK_PTR(ip, XFS_COW_FORK);
	xfs_filblks_t		rlen;
	unsigned int		resblks;
	int			error;

	/* No COW extents?  That's easy! */
	if (ifp->if_bytes == 0) {
		*end_fsb = offset_fsb;
		return 0;
	}

	resblks = XFS_EXTENTADD_SPACE_RES(mp, XFS_DATA_FORK);
	error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write, resblks, 0,
			XFS_TRANS_RESERVE | XFS_TRANS_NOFS, &tp);
	if (error)
		return error;

	/*
	 * Lock the inode.  We have to ijoin without automatic unlock because
	 * the lead transaction is the refcountbt record deletion; the data
	 * fork update follows as a deferred log item.
	 */
	xfs_ilock(ip, XFS_ILOCK_EXCL);
	xfs_trans_ijoin(tp, ip, 0);

	/*
	 * In case of racing, overlapping AIO writes no COW extents might be
	 * left by the time I/O completes for the loser of the race.  In that
	 * case we are done.
	 */
	if (!xfs_iext_lookup_extent_before(ip, ifp, end_fsb, &icur, &got) ||
	    got.br_startoff + got.br_blockcount <= offset_fsb) {
		*end_fsb = offset_fsb;
		goto out_cancel;
	}

	/*
	 * Structure copy @got into @del, then trim @del to the range that we
	 * were asked to remap.  We preserve @got for the eventual CoW fork
	 * deletion; from now on @del represents the mapping that we're
	 * actually remapping.
	 */
	del = got;
	xfs_trim_extent(&del, offset_fsb, *end_fsb - offset_fsb);

	ASSERT(del.br_blockcount > 0);

	/*
	 * Only remap real extents that contain data.  With AIO, speculative
	 * preallocations can leak into the range we are called upon, and we
	 * need to skip them.
	 */
	if (!xfs_bmap_is_real_extent(&got)) {
		*end_fsb = del.br_startoff;
		goto out_cancel;
	}

	/* Unmap the old blocks in the data fork. */
	rlen = del.br_blockcount;
	error = __xfs_bunmapi(tp, ip, del.br_startoff, &rlen, 0, 1);
	if (error)
		goto out_cancel;

	/* Trim the extent to whatever got unmapped. */
	xfs_trim_extent(&del, del.br_startoff + rlen, del.br_blockcount - rlen);
	trace_xfs_reflink_cow_remap(ip, &del);

	/* Free the CoW orphan record. */
	error = xfs_refcount_free_cow_extent(tp, del.br_startblock,
			del.br_blockcount);
	if (error)
		goto out_cancel;

	/* Map the new blocks into the data fork. */
	error = xfs_bmap_map_extent(tp, ip, &del);
	if (error)
		goto out_cancel;

	/* Charge this new data fork mapping to the on-disk quota. */
	xfs_trans_mod_dquot_byino(tp, ip, XFS_TRANS_DQ_DELBCOUNT,
			(long)del.br_blockcount);

	/* Remove the mapping from the CoW fork. */
	xfs_bmap_del_extent_cow(ip, &icur, &got, &del);

	error = xfs_trans_commit(tp);
	xfs_iunlock(ip, XFS_ILOCK_EXCL);
	if (error)
		return error;

	/* Update the caller about how much progress we made. */
	*end_fsb = del.br_startoff;
	return 0;

out_cancel:
	xfs_trans_cancel(tp);
	xfs_iunlock(ip, XFS_ILOCK_EXCL);
	return error;
}