From cbdc2ebc7c42a744d2f52a8a4adb0b725798469e Mon Sep 17 00:00:00 2001 From: Josef Bacik Date: Fri, 12 Mar 2021 15:24:58 -0500 Subject: [PATCH] btrfs: handle errors from select_reloc_root() Currently select_reloc_root() doesn't return an error, but followup patches will make it possible for it to return an error. We do have proper error recovery in do_relocation however, so handle the possibility of select_reloc_root() having an error properly instead of BUG_ON(!root). I've also adjusted select_reloc_root() to return ERR_PTR(-ENOENT) if we don't find a root, instead of NULL, to make the error case easier to deal with. I've replaced the BUG_ON(!root) with an ASSERT(0) for this case as it indicates we messed up the backref walking code, but it could also indicate corruption. Signed-off-by: Josef Bacik Reviewed-by: David Sterba Signed-off-by: David Sterba --- fs/btrfs/relocation.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c index e5fbc2c..146c7db 100644 --- a/fs/btrfs/relocation.c +++ b/fs/btrfs/relocation.c @@ -2024,8 +2024,14 @@ struct btrfs_root *select_reloc_root(struct btrfs_trans_handle *trans, if (!next || next->level <= node->level) break; } - if (!root) - return NULL; + if (!root) { + /* + * This can happen if there's fs corruption or if there's a bug + * in the backref lookup code. + */ + ASSERT(0); + return ERR_PTR(-ENOENT); + } next = node; /* setup backref node path for btrfs_reloc_cow_block */ @@ -2196,7 +2202,10 @@ static int do_relocation(struct btrfs_trans_handle *trans, upper = edge->node[UPPER]; root = select_reloc_root(trans, rc, upper, edges); - BUG_ON(!root); + if (IS_ERR(root)) { + ret = PTR_ERR(root); + goto next; + } if (upper->eb && !upper->locked) { if (!lowest) { -- 2.7.4