From: Kent Overstreet <kent.overstreet@gmail.com>
Date: Fri, 22 Oct 2021 21:33:38 +0000 (-0400)
Subject: bcachefs: Fix a transaction path overflow
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=ab44d7bdeebe316a03f37c08c1f66c13ea9aa5d5;p=linux.git

bcachefs: Fix a transaction path overflow

readdir() in a directory with many subvolumes could overflow transaction
paths - this is a simple hack around the issue.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
---

diff --git a/fs/bcachefs/dirent.c b/fs/bcachefs/dirent.c
index 2ab9cbaf71f2f..6be3ec4ec4a63 100644
--- a/fs/bcachefs/dirent.c
+++ b/fs/bcachefs/dirent.c
@@ -529,6 +529,15 @@ retry:
 			      vfs_d_type(dirent.v->d_type)))
 			break;
 		ctx->pos = dirent.k->p.offset + 1;
+
+		/*
+		 * read_target looks up subvolumes, we can overflow paths if the
+		 * directory has many subvolumes in it
+		 */
+		if (hweight64(trans.paths_allocated) > BTREE_ITER_MAX / 2) {
+			ret = -EINTR;
+			break;
+		}
 	}
 	bch2_trans_iter_exit(&trans, &iter);
 err: