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 <[email protected]> --- 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 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
