This is a note to let you know that I've just added the patch titled
btrfs: do proper error handling in create_reloc_root
to the 5.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
btrfs-do-proper-error-handling-in-create_reloc_root.patch
and it can be found in the queue-5.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 7d9b5cef037d92689c2aa51b5d44324d888f30aa
Author: Josef Bacik <josef@xxxxxxxxxxxxxx>
Date: Fri Mar 12 15:25:14 2021 -0500
btrfs: do proper error handling in create_reloc_root
[ Upstream commit 84c50ba5214c2f3c1be4a931d521ec19f55dfdc8 ]
We do memory allocations here, read blocks from disk, all sorts of
operations that could easily fail at any given point. Instead of
panicing the box, simply return the error back up the chain, all callers
at this point have proper error handling.
Signed-off-by: Josef Bacik <josef@xxxxxxxxxxxxxx>
Reviewed-by: David Sterba <dsterba@xxxxxxxx>
Signed-off-by: David Sterba <dsterba@xxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index 6a44d8f5e12e..575604ebea44 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -733,10 +733,12 @@ static struct btrfs_root *create_reloc_root(struct btrfs_trans_handle *trans,
struct extent_buffer *eb;
struct btrfs_root_item *root_item;
struct btrfs_key root_key;
- int ret;
+ int ret = 0;
+ bool must_abort = false;
root_item = kmalloc(sizeof(*root_item), GFP_NOFS);
- BUG_ON(!root_item);
+ if (!root_item)
+ return ERR_PTR(-ENOMEM);
root_key.objectid = BTRFS_TREE_RELOC_OBJECTID;
root_key.type = BTRFS_ROOT_ITEM_KEY;
@@ -748,7 +750,9 @@ static struct btrfs_root *create_reloc_root(struct btrfs_trans_handle *trans,
/* called by btrfs_init_reloc_root */
ret = btrfs_copy_root(trans, root, root->commit_root, &eb,
BTRFS_TREE_RELOC_OBJECTID);
- BUG_ON(ret);
+ if (ret)
+ goto fail;
+
/*
* Set the last_snapshot field to the generation of the commit
* root - like this ctree.c:btrfs_block_can_be_shared() behaves
@@ -769,9 +773,16 @@ static struct btrfs_root *create_reloc_root(struct btrfs_trans_handle *trans,
*/
ret = btrfs_copy_root(trans, root, root->node, &eb,
BTRFS_TREE_RELOC_OBJECTID);
- BUG_ON(ret);
+ if (ret)
+ goto fail;
}
+ /*
+ * We have changed references at this point, we must abort the
+ * transaction if anything fails.
+ */
+ must_abort = true;
+
memcpy(root_item, &root->root_item, sizeof(*root_item));
btrfs_set_root_bytenr(root_item, eb->start);
btrfs_set_root_level(root_item, btrfs_header_level(eb));
@@ -789,14 +800,25 @@ static struct btrfs_root *create_reloc_root(struct btrfs_trans_handle *trans,
ret = btrfs_insert_root(trans, fs_info->tree_root,
&root_key, root_item);
- BUG_ON(ret);
+ if (ret)
+ goto fail;
+
kfree(root_item);
reloc_root = btrfs_read_tree_root(fs_info->tree_root, &root_key);
- BUG_ON(IS_ERR(reloc_root));
+ if (IS_ERR(reloc_root)) {
+ ret = PTR_ERR(reloc_root);
+ goto abort;
+ }
set_bit(BTRFS_ROOT_SHAREABLE, &reloc_root->state);
reloc_root->last_trans = trans->transid;
return reloc_root;
+fail:
+ kfree(root_item);
+abort:
+ if (must_abort)
+ btrfs_abort_transaction(trans, ret);
+ return ERR_PTR(ret);
}
/*
