From: Filipe Manana fdmanana@suse.com
commit 236ebc20d9afc5e9ff52f3cf3f365a91583aac10 upstream.
During a rename whiteout, if btrfs_whiteout_for_rename() returns an error we can end up returning from btrfs_rename() with the log context object still in the root's log context list - this happens if 'sync_log' was set to true before we called btrfs_whiteout_for_rename() and it is dangerous because we end up with a corrupt linked list (root->log_ctxs) as the log context object was allocated on the stack.
After btrfs_rename() returns, any task that is running btrfs_sync_log() concurrently can end up crashing because that linked list is traversed by btrfs_sync_log() (through btrfs_remove_all_log_ctxs()). That results in the same issue that commit e6c617102c7e4 ("Btrfs: fix log context list corruption after rename exchange operation") fixed.
Fixes: d4682ba03ef618 ("Btrfs: sync log after logging new name") CC: stable@vger.kernel.org # 4.19+ Signed-off-by: Filipe Manana fdmanana@suse.com Signed-off-by: David Sterba dsterba@suse.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- fs/btrfs/inode.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index dec508a..c69e5b2 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -10015,6 +10015,10 @@ static int btrfs_rename(struct inode *old_dir, struct dentry *old_dentry, ret = btrfs_sync_log(trans, BTRFS_I(old_inode)->root, &ctx); if (ret) commit_transaction = true; + } else if (sync_log) { + mutex_lock(&root->log_mutex); + list_del(&ctx.list); + mutex_unlock(&root->log_mutex); } if (commit_transaction) { ret = btrfs_commit_transaction(trans);