From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from prv3-mh.provo.novell.com ([137.65.250.26]:48296 "EHLO prv3-mh.provo.novell.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750715AbdKFFrg (ORCPT ); Mon, 6 Nov 2017 00:47:36 -0500 From: Qu Wenruo To: linux-btrfs@vger.kernel.org Cc: dsterba@suse.cz, lakshmipathi.g@gmail.com, Filipe Manana Subject: [PATCH] btrfs: tree-checker: Fix false panic for sanity test Date: Mon, 6 Nov 2017 13:47:17 +0800 Message-Id: <20171106054717.18952-1-wqu@suse.com> Sender: linux-btrfs-owner@vger.kernel.org List-ID: [BUG] If we run btrfs with CONFIG_BTRFS_FS_RUN_SANITY_TESTS=y, it will instantly cause kernel panic like: ------ ... assertion failed: 0, file: fs/btrfs/disk-io.c, line: 3853 ... Call Trace: btrfs_mark_buffer_dirty+0x187/0x1f0 [btrfs] setup_items_for_insert+0x385/0x650 [btrfs] __btrfs_drop_extents+0x129a/0x1870 [btrfs] ... ----- [Cause] Btrfs will call btrfs_check_leaf() in btrfs_mark_buffer_dirty() to check if the leaf is valid with CONFIG_BTRFS_FS_RUN_SANITY_TESTS=y. However quite some btrfs_mark_buffer_dirty() callers(*) don't really initialize its item data but only initialize its item pointers, leaving item data uninitialized. This makes tree-checker catch uninitialized data as error, causing such panic. *: These callers include but not limited to setup_items_for_insert() btrfs_split_item() btrfs_expand_item() [Fix] Add a new parameter @check_item_data to btrfs_check_leaf(). With @check_item_data set to false, item data check will be skipped and fallback to old btrfs_check_leaf() behavior. So we can still get early warning if we screw up item pointers, and avoid false panic. Cc: Filipe Manana Reported-by: Lakshmipathi.G Signed-off-by: Qu Wenruo --- fs/btrfs/disk-io.c | 5 +++-- fs/btrfs/tree-checker.c | 16 +++++++++++----- fs/btrfs/tree-checker.h | 3 ++- 3 files changed, 16 insertions(+), 8 deletions(-) diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index efce9a2fa9be..c65b63d6df27 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -610,7 +610,7 @@ static int btree_readpage_end_io_hook(struct btrfs_io_bio *io_bio, * that we don't try and read the other copies of this block, just * return -EIO. */ - if (found_level == 0 && btrfs_check_leaf(root, eb)) { + if (found_level == 0 && btrfs_check_leaf(root, eb, true)) { set_bit(EXTENT_BUFFER_CORRUPT, &eb->bflags); ret = -EIO; } @@ -3848,7 +3848,8 @@ void btrfs_mark_buffer_dirty(struct extent_buffer *buf) buf->len, fs_info->dirty_metadata_batch); #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY - if (btrfs_header_level(buf) == 0 && btrfs_check_leaf(root, buf)) { + if (btrfs_header_level(buf) == 0 && + btrfs_check_leaf(root, buf, false)) { btrfs_print_leaf(buf); ASSERT(0); } diff --git a/fs/btrfs/tree-checker.c b/fs/btrfs/tree-checker.c index 114fc5f0ecc5..a4c2517fa2a1 100644 --- a/fs/btrfs/tree-checker.c +++ b/fs/btrfs/tree-checker.c @@ -242,7 +242,8 @@ static int check_leaf_item(struct btrfs_root *root, return ret; } -int btrfs_check_leaf(struct btrfs_root *root, struct extent_buffer *leaf) +int btrfs_check_leaf(struct btrfs_root *root, struct extent_buffer *leaf, + bool check_item_data) { struct btrfs_fs_info *fs_info = root->fs_info; /* No valid key type is 0, so all key should be larger than this key */ @@ -361,10 +362,15 @@ int btrfs_check_leaf(struct btrfs_root *root, struct extent_buffer *leaf) return -EUCLEAN; } - /* Check if the item size and content meet other criteria */ - ret = check_leaf_item(root, leaf, &key, slot); - if (ret < 0) - return ret; + if (check_item_data) { + /* + * Check if the item size and content meet other + * criteria + */ + ret = check_leaf_item(root, leaf, &key, slot); + if (ret < 0) + return ret; + } prev_key.objectid = key.objectid; prev_key.type = key.type; diff --git a/fs/btrfs/tree-checker.h b/fs/btrfs/tree-checker.h index 96c486e95d70..9377028e9608 100644 --- a/fs/btrfs/tree-checker.h +++ b/fs/btrfs/tree-checker.h @@ -20,7 +20,8 @@ #include "ctree.h" #include "extent_io.h" -int btrfs_check_leaf(struct btrfs_root *root, struct extent_buffer *leaf); +int btrfs_check_leaf(struct btrfs_root *root, struct extent_buffer *leaf, + bool check_item_data); int btrfs_check_node(struct btrfs_root *root, struct extent_buffer *node); #endif -- 2.14.3