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 4.9-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-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From f6033c5e333238f299c3ae03fac8cc1365b23b77 Mon Sep 17 00:00:00 2001
From: Xiyu Yang <xiyuyang19@xxxxxxxxxxxx>
Date: Tue, 21 Apr 2020 10:54:11 +0800
Subject: btrfs: fix block group leak when removing fails
From: Xiyu Yang <xiyuyang19@xxxxxxxxxxxx>
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>
---
fs/btrfs/extent-tree.c | 16 ++++++++++------
1 file changed, 10 insertions(+), 6 deletions(-)
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -10645,7 +10645,7 @@ int btrfs_remove_block_group(struct btrf
path = btrfs_alloc_path();
if (!path) {
ret = -ENOMEM;
- goto out;
+ goto out_put_group;
}
/*
@@ -10684,7 +10684,7 @@ int btrfs_remove_block_group(struct btrf
ret = btrfs_orphan_add(trans, inode);
if (ret) {
btrfs_add_delayed_iput(inode);
- goto out;
+ goto out_put_group;
}
clear_nlink(inode);
/* One for the block groups ref */
@@ -10707,13 +10707,13 @@ int btrfs_remove_block_group(struct btrf
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);
}
@@ -10871,9 +10871,9 @@ int btrfs_remove_block_group(struct btrf
ret = remove_block_group_free_space(trans, root->fs_info, 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);
@@ -11131,6 +11131,10 @@ int btrfs_init_space_info(struct btrfs_f
flags = BTRFS_BLOCK_GROUP_DATA;
ret = update_space_info(fs_info, flags, 0, 0, 0, &space_info);
}
+
+out_put_group:
+ /* Once for the lookup reference */
+ btrfs_put_block_group(block_group);
out:
return ret;
}
Patches currently in stable-queue which might be from xiyuyang19@xxxxxxxxxxxx are
queue-4.9/btrfs-fix-block-group-leak-when-removing-fails.patch
