The throttle path doesn't take cleaner_delayed_iput_mutex, which means we could think we're done flushing iputs in the data space reservation path when we could have a throttler doing an iput. There's no real reason to serialize the delayed iput flushing, so instead of taking the cleaner_delayed_iput_mutex whenever we flush the delayed iputs just replace it with an atomic counter and a waitqueue. This removes the short (or long depending on how big the inode is) window where we think there are no more pending iputs when there really are some.
Signed-off-by: Josef Bacik <jo...@toxicpanda.com> --- fs/btrfs/ctree.h | 4 +++- fs/btrfs/disk-io.c | 5 ++--- fs/btrfs/extent-tree.c | 13 ++++++++----- fs/btrfs/inode.c | 21 +++++++++++++++++++++ 4 files changed, 34 insertions(+), 9 deletions(-) diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index dc56a4d940c3..20af5d6d81f1 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -915,7 +915,8 @@ struct btrfs_fs_info { spinlock_t delayed_iput_lock; struct list_head delayed_iputs; - struct mutex cleaner_delayed_iput_mutex; + atomic_t nr_delayed_iputs; + wait_queue_head_t delayed_iputs_wait; /* this protects tree_mod_seq_list */ spinlock_t tree_mod_seq_lock; @@ -3240,6 +3241,7 @@ int btrfs_orphan_cleanup(struct btrfs_root *root); int btrfs_cont_expand(struct inode *inode, loff_t oldsize, loff_t size); void btrfs_add_delayed_iput(struct inode *inode); void btrfs_run_delayed_iputs(struct btrfs_fs_info *fs_info); +int btrfs_wait_on_delayed_iputs(struct btrfs_fs_info *fs_info); int btrfs_prealloc_file_range(struct inode *inode, int mode, u64 start, u64 num_bytes, u64 min_size, loff_t actual_len, u64 *alloc_hint); diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index f40f6fdc1019..238e0113f2d3 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -1694,9 +1694,7 @@ static int cleaner_kthread(void *arg) goto sleep; } - mutex_lock(&fs_info->cleaner_delayed_iput_mutex); btrfs_run_delayed_iputs(fs_info); - mutex_unlock(&fs_info->cleaner_delayed_iput_mutex); again = btrfs_clean_one_deleted_snapshot(root); mutex_unlock(&fs_info->cleaner_mutex); @@ -2654,7 +2652,6 @@ int open_ctree(struct super_block *sb, mutex_init(&fs_info->delete_unused_bgs_mutex); mutex_init(&fs_info->reloc_mutex); mutex_init(&fs_info->delalloc_root_mutex); - mutex_init(&fs_info->cleaner_delayed_iput_mutex); seqlock_init(&fs_info->profiles_lock); INIT_LIST_HEAD(&fs_info->dirty_cowonly_roots); @@ -2676,6 +2673,7 @@ int open_ctree(struct super_block *sb, atomic_set(&fs_info->defrag_running, 0); atomic_set(&fs_info->qgroup_op_seq, 0); atomic_set(&fs_info->reada_works_cnt, 0); + atomic_set(&fs_info->nr_delayed_iputs, 0); atomic64_set(&fs_info->tree_mod_seq, 0); fs_info->sb = sb; fs_info->max_inline = BTRFS_DEFAULT_MAX_INLINE; @@ -2753,6 +2751,7 @@ int open_ctree(struct super_block *sb, init_waitqueue_head(&fs_info->transaction_wait); init_waitqueue_head(&fs_info->transaction_blocked_wait); init_waitqueue_head(&fs_info->async_submit_wait); + init_waitqueue_head(&fs_info->delayed_iputs_wait); INIT_LIST_HEAD(&fs_info->pinned_chunks); diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index 0127d272cd2a..5b6c9fc227ff 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -4280,10 +4280,14 @@ int btrfs_alloc_data_chunk_ondemand(struct btrfs_inode *inode, u64 bytes) /* * The cleaner kthread might still be doing iput * operations. Wait for it to finish so that - * more space is released. + * more space is released. We don't need to + * explicitly run the delayed iputs here because + * the commit_transaction would have woken up + * the cleaner. */ - mutex_lock(&fs_info->cleaner_delayed_iput_mutex); - mutex_unlock(&fs_info->cleaner_delayed_iput_mutex); + ret = btrfs_wait_on_delayed_iputs(fs_info); + if (ret) + return ret; goto again; } else { btrfs_end_transaction(trans); @@ -4958,9 +4962,8 @@ static void flush_space(struct btrfs_fs_info *fs_info, * bunch of pinned space, so make sure we run the iputs before * we do our pinned bytes check below. */ - mutex_lock(&fs_info->cleaner_delayed_iput_mutex); btrfs_run_delayed_iputs(fs_info); - mutex_unlock(&fs_info->cleaner_delayed_iput_mutex); + btrfs_wait_on_delayed_iputs(fs_info); ret = may_commit_transaction(fs_info, space_info); break; diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index 0b9f3e482cea..958e30c7c744 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -3260,6 +3260,7 @@ void btrfs_add_delayed_iput(struct inode *inode) if (atomic_add_unless(&inode->i_count, -1, 1)) return; + atomic_inc(&fs_info->nr_delayed_iputs); spin_lock(&fs_info->delayed_iput_lock); ASSERT(list_empty(&binode->delayed_iput)); list_add_tail(&binode->delayed_iput, &fs_info->delayed_iputs); @@ -3280,11 +3281,31 @@ void btrfs_run_delayed_iputs(struct btrfs_fs_info *fs_info) list_del_init(&inode->delayed_iput); spin_unlock(&fs_info->delayed_iput_lock); iput(&inode->vfs_inode); + if (atomic_dec_and_test(&fs_info->nr_delayed_iputs)) + wake_up(&fs_info->delayed_iputs_wait); spin_lock(&fs_info->delayed_iput_lock); } spin_unlock(&fs_info->delayed_iput_lock); } +/** + * btrfs_wait_on_delayed_iputs - wait on the delayed iputs to be done running + * @fs_info - the fs_info for this fs + * @return - EINTR if we were killed, 0 if nothing's pending + * + * This will wait on any delayed iputs that are currently running with KILLABLE + * set. Once they are all done running we will return, unless we are killed in + * which case we return EINTR. + */ +int btrfs_wait_on_delayed_iputs(struct btrfs_fs_info *fs_info) +{ + int ret = wait_event_killable(fs_info->delayed_iputs_wait, + atomic_read(&fs_info->nr_delayed_iputs) == 0); + if (ret) + return -EINTR; + return 0; +} + /* * This creates an orphan entry for the given inode in case something goes wrong * in the middle of an unlink. -- 2.14.3