This is a note to let you know that I've just added the patch titled
btrfs: fix block group leak when removing fails
to the 5.4-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-fix-block-group-leak-when-removing-fails.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit e64eb6f9236c92956e9b13d4985f4aa005886d7c
Author: Xiyu Yang <xiyuyang19@xxxxxxxxxxxx>
Date: Tue Apr 21 10:54:11 2020 +0800
btrfs: fix block group leak when removing fails
commit f6033c5e333238f299c3ae03fac8cc1365b23b77 upstream.
btrfs_remove_block_group() invokes btrfs_lookup_block_group(), which
returns a local reference of the block group that contains the given
bytenr to "block_group" with increased refcount.
When btrfs_remove_block_group() returns, "block_group" becomes invalid,
so the refcount should be decreased to keep refcount balanced.
The reference counting issue happens in several exception handling paths
of btrfs_remove_block_group(). When those error scenarios occur such as
btrfs_alloc_path() returns NULL, the function forgets to decrease its
refcnt increased by btrfs_lookup_block_group() and will cause a refcnt
leak.
Fix this issue by jumping to "out_put_group" label and calling
btrfs_put_block_group() when those error scenarios occur.
CC: stable@xxxxxxxxxxxxxxx # 4.4+
Signed-off-by: Xiyu Yang <xiyuyang19@xxxxxxxxxxxx>
Signed-off-by: Xin Tan <tanxin.ctf@xxxxxxxxx>
Reviewed-by: David Sterba <dsterba@xxxxxxxx>
Signed-off-by: David Sterba <dsterba@xxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
diff --git a/fs/btrfs/block-group.c b/fs/btrfs/block-group.c
index 95330f40f998c..2fead6c3c6875 100644
--- a/fs/btrfs/block-group.c
+++ b/fs/btrfs/block-group.c
@@ -910,7 +910,7 @@ int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
path = btrfs_alloc_path();
if (!path) {
ret = -ENOMEM;
- goto out;
+ goto out_put_group;
}
/*
@@ -948,7 +948,7 @@ int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
ret = btrfs_orphan_add(trans, BTRFS_I(inode));
if (ret) {
btrfs_add_delayed_iput(inode);
- goto out;
+ goto out_put_group;
}
clear_nlink(inode);
/* One for the block groups ref */
@@ -971,13 +971,13 @@ int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
if (ret < 0)
- goto out;
+ goto out_put_group;
if (ret > 0)
btrfs_release_path(path);
if (ret == 0) {
ret = btrfs_del_item(trans, tree_root, path);
if (ret)
- goto out;
+ goto out_put_group;
btrfs_release_path(path);
}
@@ -1094,9 +1094,9 @@ int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
ret = remove_block_group_free_space(trans, block_group);
if (ret)
- goto out;
+ goto out_put_group;
- btrfs_put_block_group(block_group);
+ /* Once for the block groups rbtree */
btrfs_put_block_group(block_group);
ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
@@ -1119,6 +1119,10 @@ int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
/* once for the tree */
free_extent_map(em);
}
+
+out_put_group:
+ /* Once for the lookup reference */
+ btrfs_put_block_group(block_group);
out:
if (remove_rsv)
btrfs_delayed_refs_rsv_release(fs_info, 1);
