Josef Bacik
2010-Mar-12 19:28 UTC
[PATCH] Btrfs: fix small race with delalloc flushing waitqueue''s
Everytime we start a new flushing thread, we init the waitqueue if there isn''t a flushing thread running. The problem with this is we check space_info->flushing, which we clear right before doing a wake_up on the flushing waitqueue, which causes problems if we init the waitqueue in the middle of clearing the flushing flagh and calling wake_up. This is hard to hit, but the code is wrong anyway, so init the flushing/allocating waitqueue when creating the space info and let it be. I haven''t seen the panic since I''ve been using this patch. Thanks, Signed-off-by: Josef Bacik <josef@redhat.com> --- fs/btrfs/extent-tree.c | 9 ++++----- 1 files changed, 4 insertions(+), 5 deletions(-) diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index 9c6fbd0..73ac69b 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -2678,6 +2678,8 @@ static int update_space_info(struct btrfs_fs_info *info, u64 flags, INIT_LIST_HEAD(&found->block_groups); init_waitqueue_head(&found->flush_wait); init_rwsem(&found->groups_sem); + init_waitqueue_head(&found->flush_wait); + init_waitqueue_head(&found->allocate_wait); spin_lock_init(&found->lock); found->flags = flags; found->total_bytes = total_bytes; @@ -2929,12 +2931,10 @@ static void flush_delalloc(struct btrfs_root *root, spin_lock(&info->lock); - if (!info->flushing) { + if (!info->flushing) info->flushing = 1; - init_waitqueue_head(&info->flush_wait); - } else { + else wait = true; - } spin_unlock(&info->lock); @@ -2997,7 +2997,6 @@ static int maybe_allocate_chunk(struct btrfs_root *root, if (!info->allocating_chunk) { info->force_alloc = 1; info->allocating_chunk = 1; - init_waitqueue_head(&info->allocate_wait); } else { wait = true; } -- 1.6.6 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html