From 5b781cf08dfbde906809a2d4741012f9ca972320 Mon Sep 17 00:00:00 2001 From: Yevgeny Popovych Date: Fri, 7 Sep 2018 12:59:30 +0300 Subject: [PATCH] fs: btrfs: Fix tree traversal with btrfs_next_slot() MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit When traversing slots in a btree (via btrfs_path) with btrfs_next_slot(), we didn't correctly identify that the last slot in the leaf was reached and we should jump to the next leaf. This could lead to any kind of runtime errors or corruptions, like: * file data not being read at all, or is read partially * file is read but is corrupted * (any) metadata being corrupted or not read at all, etc The easiest way to reproduce this is to read a large enough file that its EXTENT_DATA items don't fit into a single leaf. Signed-off-by: Yevgeny Popovych Cc: Marek Behun Tested-by: Marek Behún --- fs/btrfs/ctree.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c index 18b47d92fe..d248d79932 100644 --- a/fs/btrfs/ctree.c +++ b/fs/btrfs/ctree.c @@ -272,7 +272,7 @@ int btrfs_next_slot(struct btrfs_path *p) { struct btrfs_leaf *leaf = &p->nodes[0]->leaf; - if (p->slots[0] >= leaf->header.nritems) + if (p->slots[0] + 1 >= leaf->header.nritems) return jump_leaf(p, 1); p->slots[0]++; -- 2.39.5