1 files changed, 168 insertions, 55 deletions

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 102c176fc29..f44b3928dc2 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -620,7 +620,7 @@ out:
 
 static int btree_io_failed_hook(struct bio *failed_bio,
 			 struct page *page, u64 start, u64 end,
-			 u64 mirror_num, struct extent_state *state)
+			 int mirror_num, struct extent_state *state)
 {
 	struct extent_io_tree *tree;
 	unsigned long len;
@@ -1890,31 +1890,32 @@ struct btrfs_root *open_ctree(struct super_block *sb,
 	u64 features;
 	struct btrfs_key location;
 	struct buffer_head *bh;
-	struct btrfs_root *extent_root = kzalloc(sizeof(struct btrfs_root),
-						 GFP_NOFS);
-	struct btrfs_root *csum_root = kzalloc(sizeof(struct btrfs_root),
-						 GFP_NOFS);
+	struct btrfs_super_block *disk_super;
 	struct btrfs_root *tree_root = btrfs_sb(sb);
-	struct btrfs_fs_info *fs_info = NULL;
-	struct btrfs_root *chunk_root = kzalloc(sizeof(struct btrfs_root),
-						GFP_NOFS);
-	struct btrfs_root *dev_root = kzalloc(sizeof(struct btrfs_root),
-					      GFP_NOFS);
+	struct btrfs_fs_info *fs_info = tree_root->fs_info;
+	struct btrfs_root *extent_root;
+	struct btrfs_root *csum_root;
+	struct btrfs_root *chunk_root;
+	struct btrfs_root *dev_root;
 	struct btrfs_root *log_tree_root;
-
 	int ret;
 	int err = -EINVAL;
 	int num_backups_tried = 0;
 	int backup_index = 0;
 
-	struct btrfs_super_block *disk_super;
+	extent_root = fs_info->extent_root =
+		kzalloc(sizeof(struct btrfs_root), GFP_NOFS);
+	csum_root = fs_info->csum_root =
+		kzalloc(sizeof(struct btrfs_root), GFP_NOFS);
+	chunk_root = fs_info->chunk_root =
+		kzalloc(sizeof(struct btrfs_root), GFP_NOFS);
+	dev_root = fs_info->dev_root =
+		kzalloc(sizeof(struct btrfs_root), GFP_NOFS);
 
-	if (!extent_root || !tree_root || !tree_root->fs_info ||
-	    !chunk_root || !dev_root || !csum_root) {
+	if (!extent_root || !csum_root || !chunk_root || !dev_root) {
 		err = -ENOMEM;
 		goto fail;
 	}
-	fs_info = tree_root->fs_info;
 
 	ret = init_srcu_struct(&fs_info->subvol_srcu);
 	if (ret) {
@@ -1954,12 +1955,6 @@ struct btrfs_root *open_ctree(struct super_block *sb,
 	mutex_init(&fs_info->reloc_mutex);
 
 	init_completion(&fs_info->kobj_unregister);
-	fs_info->tree_root = tree_root;
-	fs_info->extent_root = extent_root;
-	fs_info->csum_root = csum_root;
-	fs_info->chunk_root = chunk_root;
-	fs_info->dev_root = dev_root;
-	fs_info->fs_devices = fs_devices;
 	INIT_LIST_HEAD(&fs_info->dirty_cowonly_roots);
 	INIT_LIST_HEAD(&fs_info->space_info);
 	btrfs_mapping_init(&fs_info->mapping_tree);
@@ -2199,19 +2194,27 @@ struct btrfs_root *open_ctree(struct super_block *sb,
 	fs_info->endio_meta_write_workers.idle_thresh = 2;
 	fs_info->readahead_workers.idle_thresh = 2;
 
-	btrfs_start_workers(&fs_info->workers, 1);
-	btrfs_start_workers(&fs_info->generic_worker, 1);
-	btrfs_start_workers(&fs_info->submit_workers, 1);
-	btrfs_start_workers(&fs_info->delalloc_workers, 1);
-	btrfs_start_workers(&fs_info->fixup_workers, 1);
-	btrfs_start_workers(&fs_info->endio_workers, 1);
-	btrfs_start_workers(&fs_info->endio_meta_workers, 1);
-	btrfs_start_workers(&fs_info->endio_meta_write_workers, 1);
-	btrfs_start_workers(&fs_info->endio_write_workers, 1);
-	btrfs_start_workers(&fs_info->endio_freespace_worker, 1);
-	btrfs_start_workers(&fs_info->delayed_workers, 1);
-	btrfs_start_workers(&fs_info->caching_workers, 1);
-	btrfs_start_workers(&fs_info->readahead_workers, 1);
+	/*
+	 * btrfs_start_workers can really only fail because of ENOMEM so just
+	 * return -ENOMEM if any of these fail.
+	 */
+	ret = btrfs_start_workers(&fs_info->workers);
+	ret |= btrfs_start_workers(&fs_info->generic_worker);
+	ret |= btrfs_start_workers(&fs_info->submit_workers);
+	ret |= btrfs_start_workers(&fs_info->delalloc_workers);
+	ret |= btrfs_start_workers(&fs_info->fixup_workers);
+	ret |= btrfs_start_workers(&fs_info->endio_workers);
+	ret |= btrfs_start_workers(&fs_info->endio_meta_workers);
+	ret |= btrfs_start_workers(&fs_info->endio_meta_write_workers);
+	ret |= btrfs_start_workers(&fs_info->endio_write_workers);
+	ret |= btrfs_start_workers(&fs_info->endio_freespace_worker);
+	ret |= btrfs_start_workers(&fs_info->delayed_workers);
+	ret |= btrfs_start_workers(&fs_info->caching_workers);
+	ret |= btrfs_start_workers(&fs_info->readahead_workers);
+	if (ret) {
+		ret = -ENOMEM;
+		goto fail_sb_buffer;
+	}
 
 	fs_info->bdi.ra_pages *= btrfs_super_num_devices(disk_super);
 	fs_info->bdi.ra_pages = max(fs_info->bdi.ra_pages,
@@ -2465,21 +2468,20 @@ fail_sb_buffer:
 	btrfs_stop_workers(&fs_info->caching_workers);
 fail_alloc:
 fail_iput:
+	btrfs_mapping_tree_free(&fs_info->mapping_tree);
+
 	invalidate_inode_pages2(fs_info->btree_inode->i_mapping);
 	iput(fs_info->btree_inode);
-
-	btrfs_close_devices(fs_info->fs_devices);
-	btrfs_mapping_tree_free(&fs_info->mapping_tree);
 fail_bdi:
 	bdi_destroy(&fs_info->bdi);
 fail_srcu:
 	cleanup_srcu_struct(&fs_info->subvol_srcu);
 fail:
+	btrfs_close_devices(fs_info->fs_devices);
 	free_fs_info(fs_info);
 	return ERR_PTR(err);
 
 recovery_tree_root:
-
 	if (!btrfs_test_opt(tree_root, RECOVERY))
 		goto fail_tree_roots;
 
@@ -2579,22 +2581,10 @@ static int write_dev_supers(struct btrfs_device *device,
 	int errors = 0;
 	u32 crc;
 	u64 bytenr;
-	int last_barrier = 0;
 
 	if (max_mirrors == 0)
 		max_mirrors = BTRFS_SUPER_MIRROR_MAX;
 
-	/* make sure only the last submit_bh does a barrier */
-	if (do_barriers) {
-		for (i = 0; i < max_mirrors; i++) {
-			bytenr = btrfs_sb_offset(i);
-			if (bytenr + BTRFS_SUPER_INFO_SIZE >=
-			    device->total_bytes)
-				break;
-			last_barrier = i;
-		}
-	}
-
 	for (i = 0; i < max_mirrors; i++) {
 		bytenr = btrfs_sb_offset(i);
 		if (bytenr + BTRFS_SUPER_INFO_SIZE >= device->total_bytes)
@@ -2640,17 +2630,136 @@ static int write_dev_supers(struct btrfs_device *device,
 			bh->b_end_io = btrfs_end_buffer_write_sync;
 		}
 
-		if (i == last_barrier && do_barriers)
-			ret = submit_bh(WRITE_FLUSH_FUA, bh);
-		else
-			ret = submit_bh(WRITE_SYNC, bh);
-
+		/*
+		 * we fua the first super.  The others we allow
+		 * to go down lazy.
+		 */
+		ret = submit_bh(WRITE_FUA, bh);
 		if (ret)
 			errors++;
 	}
 	return errors < i ? 0 : -1;
 }
 
+/*
+ * endio for the write_dev_flush, this will wake anyone waiting
+ * for the barrier when it is done
+ */
+static void btrfs_end_empty_barrier(struct bio *bio, int err)
+{
+	if (err) {
+		if (err == -EOPNOTSUPP)
+			set_bit(BIO_EOPNOTSUPP, &bio->bi_flags);
+		clear_bit(BIO_UPTODATE, &bio->bi_flags);
+	}
+	if (bio->bi_private)
+		complete(bio->bi_private);
+	bio_put(bio);
+}
+
+/*
+ * trigger flushes for one the devices.  If you pass wait == 0, the flushes are
+ * sent down.  With wait == 1, it waits for the previous flush.
+ *
+ * any device where the flush fails with eopnotsupp are flagged as not-barrier
+ * capable
+ */
+static int write_dev_flush(struct btrfs_device *device, int wait)
+{
+	struct bio *bio;
+	int ret = 0;
+
+	if (device->nobarriers)
+		return 0;
+
+	if (wait) {
+		bio = device->flush_bio;
+		if (!bio)
+			return 0;
+
+		wait_for_completion(&device->flush_wait);
+
+		if (bio_flagged(bio, BIO_EOPNOTSUPP)) {
+			printk("btrfs: disabling barriers on dev %s\n",
+			       device->name);
+			device->nobarriers = 1;
+		}
+		if (!bio_flagged(bio, BIO_UPTODATE)) {
+			ret = -EIO;
+		}
+
+		/* drop the reference from the wait == 0 run */
+		bio_put(bio);
+		device->flush_bio = NULL;
+
+		return ret;
+	}
+
+	/*
+	 * one reference for us, and we leave it for the
+	 * caller
+	 */
+	device->flush_bio = NULL;;
+	bio = bio_alloc(GFP_NOFS, 0);
+	if (!bio)
+		return -ENOMEM;
+
+	bio->bi_end_io = btrfs_end_empty_barrier;
+	bio->bi_bdev = device->bdev;
+	init_completion(&device->flush_wait);
+	bio->bi_private = &device->flush_wait;
+	device->flush_bio = bio;
+
+	bio_get(bio);
+	submit_bio(WRITE_FLUSH, bio);
+
+	return 0;
+}
+
+/*
+ * send an empty flush down to each device in parallel,
+ * then wait for them
+ */
+static int barrier_all_devices(struct btrfs_fs_info *info)
+{
+	struct list_head *head;
+	struct btrfs_device *dev;
+	int errors = 0;
+	int ret;
+
+	/* send down all the barriers */
+	head = &info->fs_devices->devices;
+	list_for_each_entry_rcu(dev, head, dev_list) {
+		if (!dev->bdev) {
+			errors++;
+			continue;
+		}
+		if (!dev->in_fs_metadata || !dev->writeable)
+			continue;
+
+		ret = write_dev_flush(dev, 0);
+		if (ret)
+			errors++;
+	}
+
+	/* wait for all the barriers */
+	list_for_each_entry_rcu(dev, head, dev_list) {
+		if (!dev->bdev) {
+			errors++;
+			continue;
+		}
+		if (!dev->in_fs_metadata || !dev->writeable)
+			continue;
+
+		ret = write_dev_flush(dev, 1);
+		if (ret)
+			errors++;
+	}
+	if (errors)
+		return -EIO;
+	return 0;
+}
+
 int write_all_supers(struct btrfs_root *root, int max_mirrors)
 {
 	struct list_head *head;
@@ -2672,6 +2781,10 @@ int write_all_supers(struct btrfs_root *root, int max_mirrors)
 
 	mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
 	head = &root->fs_info->fs_devices->devices;
+
+	if (do_barriers)
+		barrier_all_devices(root->fs_info);
+
 	list_for_each_entry_rcu(dev, head, dev_list) {
 		if (!dev->bdev) {
 			total_errors++;