[PATCH 09/11] btrfs: add support for write stream IDs

[Jens Axboe <axboe@fb.com>]

Both buffered and O_DIRECT supported, and support for iterating
the below backing devices for open/close of streams.

Signed-off-by: Jens Axboe <axboe@fb.com>
---
 fs/btrfs/disk-io.c   | 69 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 fs/btrfs/extent_io.c |  1 +
 fs/btrfs/inode.c     |  1 +
 3 files changed, 71 insertions(+)

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 4545e2e2ad45..2fd3b4a6bdcd 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1748,6 +1748,72 @@ static int btrfs_congested_fn(void *congested_data, int bdi_bits)
 	return ret;
 }
 
+static int btrfs_streamid_close(struct btrfs_fs_info *info, int id)
+{
+	struct btrfs_device *device;
+
+	mutex_lock(&info->fs_devices->device_list_mutex);
+	list_for_each_entry_rcu(device, &info->fs_devices->devices, dev_list) {
+		struct backing_dev_info *bdi;
+
+		if (!device->bdev)
+			continue;
+
+		bdi = blk_get_backing_dev_info(device->bdev);
+		bdi_streamid_close(bdi, id);
+	}
+	mutex_unlock(&info->fs_devices->device_list_mutex);
+
+	return 0;
+}
+
+static int btrfs_streamid_open(struct btrfs_fs_info *info, int id)
+{
+	struct btrfs_device *device;
+	int ret = -EINVAL;
+
+	mutex_lock(&info->fs_devices->device_list_mutex);
+	list_for_each_entry_rcu(device, &info->fs_devices->devices, dev_list) {
+		struct backing_dev_info *bdi;
+
+		if (!device->bdev)
+			continue;
+
+		bdi = blk_get_backing_dev_info(device->bdev);
+		ret = bdi_streamid_open(bdi, id);
+		if (ret < 0)
+			break;
+	}
+	mutex_unlock(&info->fs_devices->device_list_mutex);
+
+	return ret;
+}
+
+static int btrfs_streamid_open_fn(void *data, unsigned int id)
+{
+	struct btrfs_fs_info *info = (struct btrfs_fs_info *) data;
+	int ret = 0;
+
+	/*
+	 * > 0 is success, return it. If we fail, fall through to
+	 * freeing the ID, if we did set it on a device.
+	 */
+	ret = btrfs_streamid_open(info, id);
+	if (ret > 0)
+		return ret;
+
+	btrfs_streamid_close(info, id);
+	return ret;
+}
+
+static int btrfs_streamid_close_fn(void *data, unsigned int id)
+{
+	struct btrfs_fs_info *info = (struct btrfs_fs_info *) data;
+
+	btrfs_streamid_close(info, id);
+	return 0;
+}
+
 static int setup_bdi(struct btrfs_fs_info *info, struct backing_dev_info *bdi)
 {
 	int err;
@@ -1760,6 +1826,9 @@ static int setup_bdi(struct btrfs_fs_info *info, struct backing_dev_info *bdi)
 	bdi->congested_fn	= btrfs_congested_fn;
 	bdi->congested_data	= info;
 	bdi->capabilities |= BDI_CAP_CGROUP_WRITEBACK;
+	bdi->streamid_open	= btrfs_streamid_open_fn;
+	bdi->streamid_close	= btrfs_streamid_close_fn;
+	bdi->streamid_data	= info;
 	return 0;
 }
 
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 392592dc7010..0f1507af8266 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -2808,6 +2808,7 @@ static int submit_extent_page(int rw, struct extent_io_tree *tree,
 	bio_add_page(bio, page, page_size, offset);
 	bio->bi_end_io = end_io_func;
 	bio->bi_private = tree;
+	bio_set_streamid(bio, inode_streamid(page->mapping->host));
 	if (wbc) {
 		wbc_init_bio(wbc, bio);
 		wbc_account_io(wbc, page, page_size);
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index d96f5cf38a2d..77661a1f9e5e 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -8338,6 +8338,7 @@ static void btrfs_submit_direct(int rw, struct bio *dio_bio,
 	atomic_set(&dip->pending_bios, 0);
 	btrfs_bio = btrfs_io_bio(io_bio);
 	btrfs_bio->logical = file_offset;
+	bio_set_streamid(io_bio, bio_get_streamid(dio_bio));
 
 	if (write) {
 		io_bio->bi_end_io = btrfs_endio_direct_write;
-- 
2.4.1.168.g1ea28e1