On 08/05/16 11:24, Holger Hoffstätte wrote: > On Wed, 03 Aug 2016 12:57:28 -0700, Liu Bo wrote: > >> When btree node (level = 1) has nritems which equals to zero, >> we can end up with panic due to insert_ptr()'s >> >> BUG_ON(slot > nritems); >> >> where slot is 1 and nritems is 0, as copy_for_split() calls >> insert_ptr(.., path->slots[1] + 1, ...); >> >> A invalid value results in the whole mess, this adds the check >> for btree's node nritems so that we stop reading block when >> when something is wrong. >> >> Signed-off-by: Liu Bo <bo.li....@oracle.com> >> --- >> fs/btrfs/disk-io.c | 17 +++++++++++++++++ >> 1 file changed, 17 insertions(+) >> >> diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c >> index 37d1780..a5a22be 100644 >> --- a/fs/btrfs/disk-io.c >> +++ b/fs/btrfs/disk-io.c >> @@ -612,6 +612,20 @@ static noinline int check_leaf(struct btrfs_root *root, >> return 0; >> } >> >> +static noinline int check_node(struct btrfs_root *root, >> + struct extent_buffer *node) >> +{ >> + unsigned long nr = btrfs_header_nritems(node); >> + >> + if (nr <= 0 || nr >= BTRFS_NODEPTRS_PER_BLOCK(root)) { >> + btrfs_crit(root->fs_info, >> + "corrupt node: block %llu root %llu nritems %lu\n", > > I think the trailing \n can be dropped here, btrfs_crit() already provides > a proper newline.
On top of that I get a whole bunch of false positives with this patch. Files that are perfectly readable without it now error out, in which case the logged nritems is always 493 - regardless of file or containing subvolume. Something is fishy here. -h -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html