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
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