From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from relay.sgi.com (relay2.corp.sgi.com [137.38.102.29]) by oss.sgi.com (Postfix) with ESMTP id B5B707F54 for ; Tue, 10 Sep 2013 11:43:22 -0500 (CDT) Message-ID: <522F4C26.2080106@sgi.com> Date: Tue, 10 Sep 2013 11:43:18 -0500 From: Mark Tinguely MIME-Version: 1.0 Subject: Re: [PATCH V2] xfs_repair: test for bad level in dir2 node References: <52274F96.2010702@sandeen.net> <522F4001.8010104@sandeen.net> In-Reply-To: <522F4001.8010104@sandeen.net> List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Errors-To: xfs-bounces@oss.sgi.com Sender: xfs-bounces@oss.sgi.com To: Eric Sandeen Cc: "'linux-xfs@oss.sgi.com'" On 09/10/13 10:51, Eric Sandeen wrote: > In traverse_int_dir2block(), the variable 'i' is the level in > the tree, with 0 being a leaf node. In the "do" loop we > start at the root, and work our way down to a leaf. > > If the first node we read is an interior node with NODE_MAGIC, > but it tells us that its level is 0 (a leaf), this is clearly > an inconsistency. > > Worse, we'd return with success, bno set, and only level[0] > in the cursor initialized. Then down this path we'll > segfault when accessing an uninitialized (and zeroed) member > of the cursor's level array: > > process_node_dir2 > traverse_int_dir2block // returns 0 w/ bno set, only level[0] init'd > process_leaf_level_dir2 > verify_dir2_path(mp, da_cursor, 0) // p_level == 0 > this_level = p_level + 1; > node = cursor->level[this_level].bp->b_addr; // level[1] uninit& 0'd > > Fix this by recognizing that an interior node w/ level 0 is invalid, and > error out as for other inconsistencies. > > By the time the level 0 test is done, we have already ensured that > this block has XFS_DA[3]_NODE_MAGIC. > > Reported-by: Jan Yves Brueckner > Signed-off-by: Eric Sandeen > --- > > V2: Drop re-test of hdr magic which is guaranteed to be NODE at this point. > fix "interior inode" - s/b "interior node" > > My only testcase for this is Jan Yves Brueckner's badly corrupted > filesystem image. With this change, we get i.e. : > > +bad level in interior inode for directory inode 39869938 > +corrupt block 6 in directory inode 39869957 > + will junk block > > diff --git a/repair/dir2.c b/repair/dir2.c > index 05bd4b7..24db351 100644 > --- a/repair/dir2.c > +++ b/repair/dir2.c > @@ -220,6 +220,15 @@ _("bad record count in inode %" PRIu64 ", count = %d, max = %d\n"), > */ > if (i == -1) { > i = da_cursor->active = nodehdr.level; > + /* Tests above ensure that we have NODE_MAGIC here */ > + if (i == 0) { > + do_warn( > +_("bad level 0 in interior node for directory inode %" PRIu64 "\n"), > + da_cursor->ino); > + libxfs_putbuf(bp); > + i = -1; > + goto error_out; > + } > if (i>= XFS_DA_NODE_MAXDEPTH) { > do_warn( > _("bad header depth for directory inode %" PRIu64 "\n"), > But moving the check out of the (i == -1) block, then the loop can check all the intermediate nodes along the way and also the ending leaf. --Mark. _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs