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| author | Filipe Manana <fdmanana@suse.com> | 2021-04-22 12:09:21 +0100 |
|---|---|---|
| committer | David Sterba <dsterba@suse.com> | 2021-04-28 20:09:42 +0200 |
| commit | ffb7c2e923cb3232454a513dcb5636e73091aa88 (patch) | |
| tree | 490fc01140619e10896a89755c892a900bbb331b /fs | |
| parent | adbd914dcde0b03bfc08ffe40b81f31b0457833f (diff) | |
| download | linux-stable-ffb7c2e923cb3232454a513dcb5636e73091aa88.tar.gz linux-stable-ffb7c2e923cb3232454a513dcb5636e73091aa88.tar.bz2 linux-stable-ffb7c2e923cb3232454a513dcb5636e73091aa88.zip | |
btrfs: do not consider send context as valid when trying to flush qgroups
At qgroup.c:try_flush_qgroup() we are asserting that current->journal_info
is either NULL or has the value BTRFS_SEND_TRANS_STUB.
However allowing for BTRFS_SEND_TRANS_STUB makes no sense because:
1) It is misleading, because send operations are read-only and do not
ever need to reserve qgroup space;
2) We already assert that current->journal_info != BTRFS_SEND_TRANS_STUB
at transaction.c:start_transaction();
3) On a kernel without CONFIG_BTRFS_ASSERT=y set, it would result in
a crash if try_flush_qgroup() is ever called in a send context, because
at transaction.c:start_transaction we cast current->journal_info into
a struct btrfs_trans_handle pointer and then dereference it.
So just do allow a send context at try_flush_qgroup() and update the
comment about it.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/btrfs/qgroup.c | 14 |
1 files changed, 9 insertions, 5 deletions
diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c index 2319c923c9e6..b1caf5acf1e2 100644 --- a/fs/btrfs/qgroup.c +++ b/fs/btrfs/qgroup.c @@ -3545,11 +3545,15 @@ static int try_flush_qgroup(struct btrfs_root *root) struct btrfs_trans_handle *trans; int ret; - /* Can't hold an open transaction or we run the risk of deadlocking */ - ASSERT(current->journal_info == NULL || - current->journal_info == BTRFS_SEND_TRANS_STUB); - if (WARN_ON(current->journal_info && - current->journal_info != BTRFS_SEND_TRANS_STUB)) + /* + * Can't hold an open transaction or we run the risk of deadlocking, + * and can't either be under the context of a send operation (where + * current->journal_info is set to BTRFS_SEND_TRANS_STUB), as that + * would result in a crash when starting a transaction and does not + * make sense either (send is a read-only operation). + */ + ASSERT(current->journal_info == NULL); + if (WARN_ON(current->journal_info)) return 0; /* |