We need an smb_mb() before waitqueue_active to avoid missing wakeups.
Before Mitch was hitting a deadlock between the ordered flushers and the
transaction commit because the ordered flushers were waiting for more refs
and were never woken up, so those smp_mb()'s are the most important.
Everything else I added for correctness sake and to avoid getting bitten by
this again somewhere else. Thanks,
Signed-off-by: Josef Bacik <jbacik@xxxxxxxxxxxx>
---
fs/btrfs/compression.c | 1 +
fs/btrfs/delayed-inode.c | 16 ++++++++++------
fs/btrfs/delayed-ref.c | 18 ++++++++++++------
fs/btrfs/disk-io.c | 11 ++++++++---
fs/btrfs/inode.c | 8 +++++---
fs/btrfs/volumes.c | 8 +++++---
6 files changed, 41 insertions(+), 21 deletions(-)
diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c
index 86eff48..43d1c5a 100644
--- a/fs/btrfs/compression.c
+++ b/fs/btrfs/compression.c
@@ -818,6 +818,7 @@ static void free_workspace(int type, struct list_head *workspace)
btrfs_compress_op[idx]->free_workspace(workspace);
atomic_dec(alloc_workspace);
wake:
+ smp_mb();
if (waitqueue_active(workspace_wait))
wake_up(workspace_wait);
}
diff --git a/fs/btrfs/delayed-inode.c b/fs/btrfs/delayed-inode.c
index 335605c..8cc9b19 100644
--- a/fs/btrfs/delayed-inode.c
+++ b/fs/btrfs/delayed-inode.c
@@ -513,9 +513,11 @@ static void __btrfs_remove_delayed_item(struct btrfs_delayed_item *delayed_item)
rb_erase(&delayed_item->rb_node, root);
delayed_item->delayed_node->count--;
atomic_dec(&delayed_root->items);
- if (atomic_read(&delayed_root->items) < BTRFS_DELAYED_BACKGROUND &&
- waitqueue_active(&delayed_root->wait))
- wake_up(&delayed_root->wait);
+ if (atomic_read(&delayed_root->items) < BTRFS_DELAYED_BACKGROUND) {
+ smp_mb();
+ if (waitqueue_active(&delayed_root->wait))
+ wake_up(&delayed_root->wait);
+ }
}
static void btrfs_release_delayed_item(struct btrfs_delayed_item *item)
@@ -1057,9 +1059,11 @@ static void btrfs_release_delayed_inode(struct btrfs_delayed_node *delayed_node)
delayed_root = delayed_node->root->fs_info->delayed_root;
atomic_dec(&delayed_root->items);
if (atomic_read(&delayed_root->items) <
- BTRFS_DELAYED_BACKGROUND &&
- waitqueue_active(&delayed_root->wait))
- wake_up(&delayed_root->wait);
+ BTRFS_DELAYED_BACKGROUND) {
+ smp_mb();
+ if (waitqueue_active(&delayed_root->wait))
+ wake_up(&delayed_root->wait);
+ }
}
}
diff --git a/fs/btrfs/delayed-ref.c b/fs/btrfs/delayed-ref.c
index da7419e..858ef02 100644
--- a/fs/btrfs/delayed-ref.c
+++ b/fs/btrfs/delayed-ref.c
@@ -662,9 +662,12 @@ int btrfs_add_delayed_tree_ref(struct btrfs_fs_info *fs_info,
add_delayed_tree_ref(fs_info, trans, &ref->node, bytenr,
num_bytes, parent, ref_root, level, action,
for_cow);
- if (!need_ref_seq(for_cow, ref_root) &&
- waitqueue_active(&fs_info->tree_mod_seq_wait))
- wake_up(&fs_info->tree_mod_seq_wait);
+ if (!need_ref_seq(for_cow, ref_root)) {
+ smp_mb();
+ if (waitqueue_active(&fs_info->tree_mod_seq_wait))
+ wake_up(&fs_info->tree_mod_seq_wait);
+ }
+
spin_unlock(&delayed_refs->lock);
if (need_ref_seq(for_cow, ref_root))
btrfs_qgroup_record_ref(trans, &ref->node, extent_op);
@@ -713,9 +716,11 @@ int btrfs_add_delayed_data_ref(struct btrfs_fs_info *fs_info,
add_delayed_data_ref(fs_info, trans, &ref->node, bytenr,
num_bytes, parent, ref_root, owner, offset,
action, for_cow);
- if (!need_ref_seq(for_cow, ref_root) &&
- waitqueue_active(&fs_info->tree_mod_seq_wait))
- wake_up(&fs_info->tree_mod_seq_wait);
+ if (!need_ref_seq(for_cow, ref_root)) {
+ smp_mb();
+ if (waitqueue_active(&fs_info->tree_mod_seq_wait))
+ wake_up(&fs_info->tree_mod_seq_wait);
+ }
spin_unlock(&delayed_refs->lock);
if (need_ref_seq(for_cow, ref_root))
btrfs_qgroup_record_ref(trans, &ref->node, extent_op);
@@ -744,6 +749,7 @@ int btrfs_add_delayed_extent_op(struct btrfs_fs_info *fs_info,
num_bytes, BTRFS_UPDATE_DELAYED_HEAD,
extent_op->is_data);
+ smp_mb();
if (waitqueue_active(&fs_info->tree_mod_seq_wait))
wake_up(&fs_info->tree_mod_seq_wait);
spin_unlock(&delayed_refs->lock);
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 502b20c..a355c89 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -756,9 +756,11 @@ static void run_one_async_done(struct btrfs_work *work)
atomic_dec(&fs_info->nr_async_submits);
- if (atomic_read(&fs_info->nr_async_submits) < limit &&
- waitqueue_active(&fs_info->async_submit_wait))
- wake_up(&fs_info->async_submit_wait);
+ if (atomic_read(&fs_info->nr_async_submits) < limit) {
+ smp_mb();
+ if (waitqueue_active(&fs_info->async_submit_wait))
+ wake_up(&fs_info->async_submit_wait);
+ }
/* If an error occured we just want to clean up the bio and move on */
if (async->error) {
@@ -3785,14 +3787,17 @@ int btrfs_cleanup_transaction(struct btrfs_root *root)
/* FIXME: cleanup wait for commit */
t->in_commit = 1;
t->blocked = 1;
+ smp_mb();
if (waitqueue_active(&root->fs_info->transaction_blocked_wait))
wake_up(&root->fs_info->transaction_blocked_wait);
t->blocked = 0;
+ smp_mb();
if (waitqueue_active(&root->fs_info->transaction_wait))
wake_up(&root->fs_info->transaction_wait);
t->commit_done = 1;
+ smp_mb();
if (waitqueue_active(&t->commit_wait))
wake_up(&t->commit_wait);
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 4b82ae2..acea7d9 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -1010,9 +1010,11 @@ static noinline void async_cow_submit(struct btrfs_work *work)
atomic_sub(nr_pages, &root->fs_info->async_delalloc_pages);
if (atomic_read(&root->fs_info->async_delalloc_pages) <
- 5 * 1024 * 1024 &&
- waitqueue_active(&root->fs_info->async_submit_wait))
- wake_up(&root->fs_info->async_submit_wait);
+ 5 * 1024 * 1024) {
+ smp_mb();
+ if (waitqueue_active(&root->fs_info->async_submit_wait))
+ wake_up(&root->fs_info->async_submit_wait);
+ }
if (async_cow->inode)
submit_compressed_extents(async_cow->inode, async_cow);
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index b8708f9..871f43f 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -229,9 +229,11 @@ loop_lock:
cur->bi_next = NULL;
atomic_dec(&fs_info->nr_async_bios);
- if (atomic_read(&fs_info->nr_async_bios) < limit &&
- waitqueue_active(&fs_info->async_submit_wait))
- wake_up(&fs_info->async_submit_wait);
+ if (atomic_read(&fs_info->nr_async_bios) < limit) {
+ smp_mb();
+ if (waitqueue_active(&fs_info->async_submit_wait))
+ wake_up(&fs_info->async_submit_wait);
+ }
BUG_ON(atomic_read(&cur->bi_cnt) == 0);
--
1.7.7.6
--
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