Commit f4e4c4e6 authored by Andreas Gruenbacher's avatar Andreas Gruenbacher
Browse files

gfs2: fix address space truncation during withdraw 



When a withdrawn filesystem's inodes are being evicted, the address spaces of
those inodes still need to be truncated but we can no longer start new
transactions.  We still don't want gfs2_invalidate_folio() to race with
gfs2_log_flush(), so take a read lock on sdp->sd_log_flush_lock in that case.
(It may not be obvious, but gfs2_invalidate_folio() is a jdata-only address
space operation.)

Signed-off-by: default avatarAndreas Gruenbacher <agruenba@redhat.com>
parent 7d2da6ed

fs/gfs2/log.c

+11 −6
Original line number Diff line number Diff line
@@ -1024,17 +1024,22 @@ void gfs2_remove_from_journal(struct buffer_head *bh, int meta) 
		trace_gfs2_pin(bd, 0);

		atomic_dec(&sdp->sd_log_pinned);

		list_del_init(&bd->bd_list);

		if (tr) {

			if (meta == REMOVE_META)

				tr->tr_num_buf_rm++;

			else

				tr->tr_num_databuf_rm++;

			set_bit(TR_TOUCHED, &tr->tr_flags);

		}

		was_pinned = 1;

		brelse(bh);

	}

	if (bd) {

		if (bd->bd_tr) {

			if (tr)

				gfs2_trans_add_revoke(sdp, bd);

			else

				 gfs2_remove_from_ail(bd);

		} else if (was_pinned) {

			bh->b_private = NULL;

			kmem_cache_free(gfs2_bufdata_cachep, bd);

fs/gfs2/super.c

+28 −13
Original line number Diff line number Diff line
@@ -1339,27 +1339,44 @@ static int gfs2_truncate_inode_pages(struct inode *inode) 
	struct gfs2_sbd *sdp = GFS2_SB(inode);

	struct address_space *mapping = &inode->i_data;

	bool need_trans = gfs2_is_jdata(ip) && mapping->nrpages;

	int ret;

	int ret = 0;



	/*

	 * Truncating a jdata inode address space may create revokes in

	 * truncate_inode_pages() -> gfs2_invalidate_folio() -> ... ->

	 * gfs2_remove_from_journal(), so we need a transaction here.

	 *

	 * FIXME: During a withdraw, no new transactions can be created.

	 * In that case, we skip the truncate, but that doesn't help because

	 * truncate_inode_pages_final() will then call gfs2_invalidate_folio()

	 * again, and outside of a transaction.

	 * During a withdraw, no new transactions can be created.  We still

	 * take the log flush lock to prevent truncate from racing with

	 * gfs2_log_flush().

	 */

	if (need_trans) {

		ret = gfs2_trans_begin(sdp, 0, sdp->sd_jdesc->jd_blocks);

		if (ret)

			return ret;

			down_read(&sdp->sd_log_flush_lock);

	}

	truncate_inode_pages(mapping, 0);

	if (need_trans)

	if (need_trans) {

		if (ret)

			up_read(&sdp->sd_log_flush_lock);

		else

			gfs2_trans_end(sdp);

	return 0;

	}

	return ret;

}



static void gfs2_truncate_inode_pages_final(struct inode *inode)

{

	struct gfs2_inode *ip = GFS2_I(inode);

	struct gfs2_sbd *sdp = GFS2_SB(inode);

	struct address_space *mapping = &inode->i_data;

	bool need_lock = gfs2_is_jdata(ip) && mapping->nrpages;



	if (need_lock)

		down_read(&sdp->sd_log_flush_lock);

	truncate_inode_pages_final(mapping);

	if (need_lock)

		up_read(&sdp->sd_log_flush_lock);

}



/*
@@ -1398,10 +1415,8 @@ static int evict_linked_inode(struct inode *inode, struct gfs2_holder *gh) 


clean:

	ret = gfs2_truncate_inode_pages(inode);

	if (ret)

		return ret;

	truncate_inode_pages(metamapping, 0);

	return 0;

	return ret;

}



/**
@@ -1472,7 +1487,7 @@ static void gfs2_evict_inode(struct inode *inode) 
out:

	if (gfs2_holder_initialized(&gh))

		gfs2_glock_dq_uninit(&gh);

	truncate_inode_pages_final(&inode->i_data);

	gfs2_truncate_inode_pages_final(inode);

	if (ip->i_qadata)

		gfs2_assert_warn(sdp, ip->i_qadata->qa_ref == 0);

	gfs2_rs_deltree(&ip->i_res);