hollalinux
/
linux-sg2042
mirror of https://github.com/sophgo/linux-riscv.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

btrfs: clear DEAD_RELOC_TREE before dropping the reloc root 

The DEAD_RELOC_TREE flag is in place in order to avoid a use after free
in init_reloc_root, tracking the presence of reloc_root.  However adding
the explicit tree references in previous patches makes the use after
free impossible because at this point we no longer have a reloc_control
set on the fs_info and thus cannot enter the function.

So move this to be coupled with clearing the root->reloc_root so we're
consistent with all other operations of the reloc root.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ update changelog ]
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Josef Bacik 2020-03-13 11:44:46 -04:00 committed by David Sterba
parent 1a0afa0ecf
commit f28de8d8fd
1 changed files with 6 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
fs/btrfs/relocation.c
View File

@ -2275,18 +2275,18 @@ static int clean_dirty_subvols(struct reloc_control *rc)
list_del_init(&root->reloc_dirty_list);
root->reloc_root = NULL;
if (reloc_root) {
ret2 = btrfs_drop_snapshot(reloc_root, 0, 1);
if (ret2 < 0 && !ret)
ret = ret2;
}
/*
* Need barrier to ensure clear_bit() only happens after
* root->reloc_root = NULL. Pairs with have_reloc_root.
*/
smp_wmb();
clear_bit(BTRFS_ROOT_DEAD_RELOC_TREE, &root->state);
if (reloc_root) {
ret2 = btrfs_drop_snapshot(reloc_root, 0, 1);
if (ret2 < 0 && !ret)
ret = ret2;
}
btrfs_put_root(root);
} else {
/* Orphan reloc tree, just clean it up */