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Commit 6dcfac4f authored by Adrian Hunter's avatar Adrian Hunter Committed by Artem Bityutskiy
Browse files

UBIFS: TNC / GC race fixes 



- update GC sequence number if any nodes may have been moved
even if GC did not finish the LEB
- don't ignore error return when reading

Signed-off-by: default avatarAdrian Hunter <ext-adrian.hunter@nokia.com>
Signed-off-by: default avatarArtem Bityutskiy <Artem.Bityutskiy@nokia.com>
parent 0855f310

fs/ubifs/gc.c

+11 −3
Original line number Original line Diff line number Diff line
@@ -334,15 +334,15 @@ int ubifs_garbage_collect_leb(struct ubifs_info *c, struct ubifs_lprops *lp) 




		err = move_nodes(c, sleb);

		err = move_nodes(c, sleb);

		if (err)

		if (err)

			goto out;

			goto out_inc_seq;





		err = gc_sync_wbufs(c);

		err = gc_sync_wbufs(c);

		if (err)

		if (err)

			goto out;

			goto out_inc_seq;





		err = ubifs_change_one_lp(c, lnum, c->leb_size, 0, 0, 0, 0);

		err = ubifs_change_one_lp(c, lnum, c->leb_size, 0, 0, 0, 0);

		if (err)

		if (err)

			goto out;

			goto out_inc_seq;





		/* Allow for races with TNC */

		/* Allow for races with TNC */

		c->gced_lnum = lnum;

		c->gced_lnum = lnum;
@@ -369,6 +369,14 @@ int ubifs_garbage_collect_leb(struct ubifs_info *c, struct ubifs_lprops *lp) 
out:

out:

	ubifs_scan_destroy(sleb);

	ubifs_scan_destroy(sleb);

	return err;

	return err;



out_inc_seq:

	/* We may have moved at least some nodes so allow for races with TNC */

	c->gced_lnum = lnum;

	smp_wmb();

	c->gc_seq += 1;

	smp_wmb();

	goto out;

}

}





/**

/**

fs/ubifs/tnc.c

+1 −1
Original line number Original line Diff line number Diff line
@@ -1476,7 +1476,7 @@ int ubifs_tnc_locate(struct ubifs_info *c, const union ubifs_key *key, 
	}

	}





	err = fallible_read_node(c, key, &zbr, node);

	err = fallible_read_node(c, key, &zbr, node);

	if (maybe_leb_gced(c, zbr.lnum, gc_seq1)) {

	if (err <= 0 || maybe_leb_gced(c, zbr.lnum, gc_seq1)) {

		/*

		/*

		 * The node may have been GC'ed out from under us so try again

		 * The node may have been GC'ed out from under us so try again

		 * while keeping the TNC mutex locked.

		 * while keeping the TNC mutex locked.