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Date: Thu, 7 Sep 2023 11:43:35 -0400
From: Sasha Levin <sashal@...nel.org>
To: linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc: Qu Wenruo <wqu@...e.com>, Josef Bacik <josef@...icpanda.com>,
David Sterba <dsterba@...e.com>,
Sasha Levin <sashal@...nel.org>, clm@...com,
linux-btrfs@...r.kernel.org
Subject: [PATCH AUTOSEL 6.5 4/6] btrfs: handle errors properly in update_inline_extent_backref()
From: Qu Wenruo <wqu@...e.com>
[ Upstream commit 257614301a5db9f7b0548584ca207ad7785c8b89 ]
[PROBLEM]
Inside function update_inline_extent_backref(), we have several
BUG_ON()s along with some ASSERT()s which can be triggered by corrupted
filesystem.
[ANAYLYSE]
Most of those BUG_ON()s and ASSERT()s are just a way of handling
unexpected on-disk data.
Although we have tree-checker to rule out obviously incorrect extent
tree blocks, it's not enough for these ones. Thus we need proper error
handling for them.
[FIX]
Thankfully all the callers of update_inline_extent_backref() would
eventually handle the errror by aborting the current transaction.
So this patch would do the proper error handling by:
- Make update_inline_extent_backref() to return int
The return value would be either 0 or -EUCLEAN.
- Replace BUG_ON()s and ASSERT()s with proper error handling
This includes:
* Dump the bad extent tree leaf
* Output an error message for the cause
This would include the extent bytenr, num_bytes (if needed), the bad
values and expected good values.
* Return -EUCLEAN
Note here we remove all the WARN_ON()s, as eventually the transaction
would be aborted, thus a backtrace would be triggered anyway.
- Better comments on why we expect refs == 1 and refs_to_mode == -1 for
tree blocks
Reviewed-by: Josef Bacik <josef@...icpanda.com>
Signed-off-by: Qu Wenruo <wqu@...e.com>
Reviewed-by: David Sterba <dsterba@...e.com>
Signed-off-by: David Sterba <dsterba@...e.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
fs/btrfs/extent-tree.c | 73 +++++++++++++++++++++++++++++++++++-------
1 file changed, 61 insertions(+), 12 deletions(-)
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index f396a9afa4032..21e48c422bc50 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -402,11 +402,11 @@ int btrfs_get_extent_inline_ref_type(const struct extent_buffer *eb,
}
}
+ WARN_ON(1);
btrfs_print_leaf(eb);
btrfs_err(eb->fs_info,
"eb %llu iref 0x%lx invalid extent inline ref type %d",
eb->start, (unsigned long)iref, type);
- WARN_ON(1);
return BTRFS_REF_TYPE_INVALID;
}
@@ -1079,13 +1079,13 @@ static int lookup_extent_backref(struct btrfs_trans_handle *trans,
/*
* helper to update/remove inline back ref
*/
-static noinline_for_stack
-void update_inline_extent_backref(struct btrfs_path *path,
+static noinline_for_stack int update_inline_extent_backref(struct btrfs_path *path,
struct btrfs_extent_inline_ref *iref,
int refs_to_mod,
struct btrfs_delayed_extent_op *extent_op)
{
struct extent_buffer *leaf = path->nodes[0];
+ struct btrfs_fs_info *fs_info = leaf->fs_info;
struct btrfs_extent_item *ei;
struct btrfs_extent_data_ref *dref = NULL;
struct btrfs_shared_data_ref *sref = NULL;
@@ -1098,18 +1098,33 @@ void update_inline_extent_backref(struct btrfs_path *path,
ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
refs = btrfs_extent_refs(leaf, ei);
- WARN_ON(refs_to_mod < 0 && refs + refs_to_mod <= 0);
+ if (unlikely(refs_to_mod < 0 && refs + refs_to_mod <= 0)) {
+ struct btrfs_key key;
+ u32 extent_size;
+
+ btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
+ if (key.type == BTRFS_METADATA_ITEM_KEY)
+ extent_size = fs_info->nodesize;
+ else
+ extent_size = key.offset;
+ btrfs_print_leaf(leaf);
+ btrfs_err(fs_info,
+ "invalid refs_to_mod for extent %llu num_bytes %u, has %d expect >= -%llu",
+ key.objectid, extent_size, refs_to_mod, refs);
+ return -EUCLEAN;
+ }
refs += refs_to_mod;
btrfs_set_extent_refs(leaf, ei, refs);
if (extent_op)
__run_delayed_extent_op(extent_op, leaf, ei);
+ type = btrfs_get_extent_inline_ref_type(leaf, iref, BTRFS_REF_TYPE_ANY);
/*
- * If type is invalid, we should have bailed out after
- * lookup_inline_extent_backref().
+ * Function btrfs_get_extent_inline_ref_type() has already printed
+ * error messages.
*/
- type = btrfs_get_extent_inline_ref_type(leaf, iref, BTRFS_REF_TYPE_ANY);
- ASSERT(type != BTRFS_REF_TYPE_INVALID);
+ if (unlikely(type == BTRFS_REF_TYPE_INVALID))
+ return -EUCLEAN;
if (type == BTRFS_EXTENT_DATA_REF_KEY) {
dref = (struct btrfs_extent_data_ref *)(&iref->offset);
@@ -1119,10 +1134,43 @@ void update_inline_extent_backref(struct btrfs_path *path,
refs = btrfs_shared_data_ref_count(leaf, sref);
} else {
refs = 1;
- BUG_ON(refs_to_mod != -1);
+ /*
+ * For tree blocks we can only drop one ref for it, and tree
+ * blocks should not have refs > 1.
+ *
+ * Furthermore if we're inserting a new inline backref, we
+ * won't reach this path either. That would be
+ * setup_inline_extent_backref().
+ */
+ if (unlikely(refs_to_mod != -1)) {
+ struct btrfs_key key;
+
+ btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
+
+ btrfs_print_leaf(leaf);
+ btrfs_err(fs_info,
+ "invalid refs_to_mod for tree block %llu, has %d expect -1",
+ key.objectid, refs_to_mod);
+ return -EUCLEAN;
+ }
}
- BUG_ON(refs_to_mod < 0 && refs < -refs_to_mod);
+ if (unlikely(refs_to_mod < 0 && refs < -refs_to_mod)) {
+ struct btrfs_key key;
+ u32 extent_size;
+
+ btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
+ if (key.type == BTRFS_METADATA_ITEM_KEY)
+ extent_size = fs_info->nodesize;
+ else
+ extent_size = key.offset;
+ btrfs_print_leaf(leaf);
+ btrfs_err(fs_info,
+"invalid refs_to_mod for backref entry, iref %lu extent %llu num_bytes %u, has %d expect >= -%llu",
+ (unsigned long)iref, key.objectid, extent_size,
+ refs_to_mod, refs);
+ return -EUCLEAN;
+ }
refs += refs_to_mod;
if (refs > 0) {
@@ -1142,6 +1190,7 @@ void update_inline_extent_backref(struct btrfs_path *path,
btrfs_truncate_item(path, item_size, 1);
}
btrfs_mark_buffer_dirty(leaf);
+ return 0;
}
static noinline_for_stack
@@ -1170,7 +1219,7 @@ int insert_inline_extent_backref(struct btrfs_trans_handle *trans,
bytenr, num_bytes, root_objectid, path->slots[0]);
return -EUCLEAN;
}
- update_inline_extent_backref(path, iref, refs_to_add, extent_op);
+ ret = update_inline_extent_backref(path, iref, refs_to_add, extent_op);
} else if (ret == -ENOENT) {
setup_inline_extent_backref(trans->fs_info, path, iref, parent,
root_objectid, owner, offset,
@@ -1190,7 +1239,7 @@ static int remove_extent_backref(struct btrfs_trans_handle *trans,
BUG_ON(!is_data && refs_to_drop != 1);
if (iref)
- update_inline_extent_backref(path, iref, -refs_to_drop, NULL);
+ ret = update_inline_extent_backref(path, iref, -refs_to_drop, NULL);
else if (is_data)
ret = remove_extent_data_ref(trans, root, path, refs_to_drop);
else
--
2.40.1
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