[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 <fdman...@gmail.com>
Reported-by: Lakshmipathi.G <lakshmipath...@gmail.com>
Signed-off-by: Qu Wenruo <w...@suse.com>
---
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
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