diff options
| author | Josef Bacik <josef@toxicpanda.com> | 2021-03-12 15:25:15 -0500 |
|---|---|---|
| committer | David Sterba <dsterba@suse.com> | 2021-04-19 17:25:20 +0200 |
| commit | 39200e59089e260af8edb9feeb69c54ba51699c5 (patch) | |
| tree | 909c827d87d3d6ff2f5e7e308be05d76ba5e0650 /fs/btrfs | |
| parent | 84c50ba5214c2f3c1be4a931d521ec19f55dfdc8 (diff) | |
btrfs: validate root::reloc_root after recording root in trans
If we fail to setup a root->reloc_root in a different thread that path
will error out, however it still leaves root->reloc_root NULL but would
still appear set up in the transaction. Subsequent calls to
btrfs_record_root_in_transaction would succeed without attempting to
create the reloc root, as the transid has already been updated.
Handle this case by making sure we have a root->reloc_root set after a
btrfs_record_root_in_transaction call so we don't end up dereferencing a
NULL pointer.
Reported-by: Zygo Blaxell <ce3g8jdj@umail.furryterror.org>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs/btrfs')
| -rw-r--r-- | fs/btrfs/relocation.c | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c index 11cda7dd7ee6..2d9c0cda5e1c 100644 --- a/fs/btrfs/relocation.c +++ b/fs/btrfs/relocation.c @@ -2082,6 +2082,13 @@ struct btrfs_root *select_reloc_root(struct btrfs_trans_handle *trans, return ERR_PTR(ret); root = root->reloc_root; + /* + * We could have raced with another thread which failed, so + * root->reloc_root may not be set, return ENOENT in this case. + */ + if (!root) + return ERR_PTR(-ENOENT); + if (next->new_bytenr != root->node->start) { /* * We just created the reloc root, so we shouldn't have @@ -2579,6 +2586,14 @@ static int relocate_tree_block(struct btrfs_trans_handle *trans, ret = btrfs_record_root_in_trans(trans, root); if (ret) goto out; + /* + * Another thread could have failed, need to check if we + * have reloc_root actually set. + */ + if (!root->reloc_root) { + ret = -ENOENT; + goto out; + } root = root->reloc_root; node->new_bytenr = root->node->start; btrfs_put_root(node->root); |