btrfs: add lockdep annotations for num_extwriters wait event

Similarly to the num_writers wait event in fs/btrfs/transaction.c add a
lockdep annotation for the num_extwriters wait event.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Ioannis Angelakopoulos <iangelak@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 707e644..e886cf6 100644 (file)
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1097,6 +1097,7 @@ struct btrfs_fs_info {
         * compiled without lockdep).
         */
        struct lockdep_map btrfs_trans_num_writers_map;
+       struct lockdep_map btrfs_trans_num_extwriters_map;
 
 #ifdef CONFIG_BTRFS_FS_REF_VERIFY
        spinlock_t ref_verify_lock;

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index a04b32f..811d743 100644 (file)
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -2991,6 +2991,7 @@ void btrfs_init_fs_info(struct btrfs_fs_info *fs_info)
        seqlock_init(&fs_info->profiles_lock);
 
        btrfs_lockdep_init_map(fs_info, btrfs_trans_num_writers);
+       btrfs_lockdep_init_map(fs_info, btrfs_trans_num_extwriters);
 
        INIT_LIST_HEAD(&fs_info->dirty_cowonly_roots);
        INIT_LIST_HEAD(&fs_info->space_info);

diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index b3cb54d..44e47db 100644 (file)
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -314,6 +314,7 @@ loop:
                extwriter_counter_inc(cur_trans, type);
                spin_unlock(&fs_info->trans_lock);
                btrfs_lockdep_acquire(fs_info, btrfs_trans_num_writers);
+               btrfs_lockdep_acquire(fs_info, btrfs_trans_num_extwriters);
                return 0;
        }
        spin_unlock(&fs_info->trans_lock);
@@ -336,6 +337,7 @@ loop:
                return -ENOMEM;
 
        btrfs_lockdep_acquire(fs_info, btrfs_trans_num_writers);
+       btrfs_lockdep_acquire(fs_info, btrfs_trans_num_extwriters);
 
        spin_lock(&fs_info->trans_lock);
        if (fs_info->running_transaction) {
@@ -343,11 +345,13 @@ loop:
                 * someone started a transaction after we unlocked.  Make sure
                 * to redo the checks above
                 */
+               btrfs_lockdep_release(fs_info, btrfs_trans_num_extwriters);
                btrfs_lockdep_release(fs_info, btrfs_trans_num_writers);
                kfree(cur_trans);
                goto loop;
        } else if (BTRFS_FS_ERROR(fs_info)) {
                spin_unlock(&fs_info->trans_lock);
+               btrfs_lockdep_release(fs_info, btrfs_trans_num_extwriters);
                btrfs_lockdep_release(fs_info, btrfs_trans_num_writers);
                kfree(cur_trans);
                return -EROFS;
@@ -1028,6 +1032,7 @@ static int __btrfs_end_transaction(struct btrfs_trans_handle *trans,
 
        cond_wake_up(&cur_trans->writer_wait);
 
+       btrfs_lockdep_release(info, btrfs_trans_num_extwriters);
        btrfs_lockdep_release(info, btrfs_trans_num_writers);
 
        btrfs_put_transaction(cur_trans);
@@ -2270,6 +2275,13 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans)
        if (ret)
                goto lockdep_release;
 
+       /*
+        * The thread has started/joined the transaction thus it holds the
+        * lockdep map as a reader. It has to release it before acquiring the
+        * lockdep map as a writer.
+        */
+       btrfs_lockdep_release(fs_info, btrfs_trans_num_extwriters);
+       btrfs_might_wait_for_event(fs_info, btrfs_trans_num_extwriters);
        wait_event(cur_trans->writer_wait,
                   extwriter_counter_read(cur_trans) == 0);
 
@@ -2541,6 +2553,7 @@ cleanup_transaction:
        return ret;
 
 lockdep_release:
+       btrfs_lockdep_release(fs_info, btrfs_trans_num_extwriters);
        btrfs_lockdep_release(fs_info, btrfs_trans_num_writers);
        goto cleanup_transaction;
 }