1 files changed, 147 insertions, 42 deletions

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 102c176fc29c..632f8f3cc9db 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);
@@ -2465,21 +2460,20 @@ 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 +2573,10 @@ 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 +2622,136 @@ 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 +2773,10 @@ 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++;