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authorQu Wenruo <wqu@suse.com>2017-11-08 08:54:24 +0800
committerDavid Sterba <dsterba@suse.com>2017-11-28 14:59:09 +0100
commit69fc6cbbac542c349b3d350d10f6e394c253c81d (patch)
tree4c0fef143573a65892fea4f0e77974904f4ec3b6
parentebb70442cdd4872260c2415929c456be3562da82 (diff)
downloadlinux-69fc6cbbac542c349b3d350d10f6e394c253c81d.tar.bz2
btrfs: tree-checker: Fix false panic for sanity test
[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 <fdmanana@gmail.com> Reported-by: Lakshmipathi.G <lakshmipathi.g@gmail.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: Liu Bo <bo.li.liu@oracle.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
-rw-r--r--fs/btrfs/disk-io.c10
-rw-r--r--fs/btrfs/tree-checker.c27
-rw-r--r--fs/btrfs/tree-checker.h14
3 files changed, 43 insertions, 8 deletions
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index efce9a2fa9be..10a2a579cc7f 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_full(root, eb)) {
set_bit(EXTENT_BUFFER_CORRUPT, &eb->bflags);
ret = -EIO;
}
@@ -3848,7 +3848,13 @@ 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)) {
+ /*
+ * Since btrfs_mark_buffer_dirty() can be called with item pointer set
+ * but item data not updated.
+ * So here we should only check item pointers, not item data.
+ */
+ if (btrfs_header_level(buf) == 0 &&
+ btrfs_check_leaf_relaxed(root, buf)) {
btrfs_print_leaf(buf);
ASSERT(0);
}
diff --git a/fs/btrfs/tree-checker.c b/fs/btrfs/tree-checker.c
index 114fc5f0ecc5..ce4ed6ec8f39 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)
+static int 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;
@@ -374,6 +380,17 @@ int btrfs_check_leaf(struct btrfs_root *root, struct extent_buffer *leaf)
return 0;
}
+int btrfs_check_leaf_full(struct btrfs_root *root, struct extent_buffer *leaf)
+{
+ return check_leaf(root, leaf, true);
+}
+
+int btrfs_check_leaf_relaxed(struct btrfs_root *root,
+ struct extent_buffer *leaf)
+{
+ return check_leaf(root, leaf, false);
+}
+
int btrfs_check_node(struct btrfs_root *root, struct extent_buffer *node)
{
unsigned long nr = btrfs_header_nritems(node);
diff --git a/fs/btrfs/tree-checker.h b/fs/btrfs/tree-checker.h
index 96c486e95d70..3d53e8d6fda0 100644
--- a/fs/btrfs/tree-checker.h
+++ b/fs/btrfs/tree-checker.h
@@ -20,7 +20,19 @@
#include "ctree.h"
#include "extent_io.h"
-int btrfs_check_leaf(struct btrfs_root *root, struct extent_buffer *leaf);
+/*
+ * Comprehensive leaf checker.
+ * Will check not only the item pointers, but also every possible member
+ * in item data.
+ */
+int btrfs_check_leaf_full(struct btrfs_root *root, struct extent_buffer *leaf);
+
+/*
+ * Less strict leaf checker.
+ * Will only check item pointers, not reading item data.
+ */
+int btrfs_check_leaf_relaxed(struct btrfs_root *root,
+ struct extent_buffer *leaf);
int btrfs_check_node(struct btrfs_root *root, struct extent_buffer *node);
#endif