From: Filipe Manana <fdmanana@xxxxxxxx>
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@xxxxxxxxxxxxxxx # 4.19+
Signed-off-by: Filipe Manana <fdmanana@xxxxxxxx>
Signed-off-by: David Sterba <dsterba@xxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/btrfs/inode.c | 4 ++++
1 file changed, 4 insertions(+)
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -10015,6 +10015,10 @@ out_fail:
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);
