2 files changed, 39 insertions, 32 deletions

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 33b744a5ac03..9f68c6898653 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1668,8 +1668,6 @@ struct btrfs_root *open_ctree(struct super_block *sb,
         init_waitqueue_head(&fs_info->scrub_pause_wait);
         init_rwsem(&fs_info->scrub_super_lock);
         fs_info->scrub_workers_refcnt = 0;
-        btrfs_init_workers(&fs_info->scrub_workers, "scrub",
-                           fs_info->thread_pool_size, &fs_info->generic_worker);
 
         sb->s_blocksize = 4096;
         sb->s_blocksize_bits = blksize_bits(4096);
diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
index df50fd1eca8f..a8d03d5efb5d 100644
--- a/fs/btrfs/scrub.c
+++ b/fs/btrfs/scrub.c
@@ -16,13 +16,7 @@
  * Boston, MA 021110-1307, USA.
  */
 
-#include <linux/sched.h>
-#include <linux/pagemap.h>
-#include <linux/writeback.h>
 #include <linux/blkdev.h>
-#include <linux/rbtree.h>
-#include <linux/slab.h>
-#include <linux/workqueue.h>
 #include "ctree.h"
 #include "volumes.h"
 #include "disk-io.h"
@@ -804,18 +798,12 @@ static noinline_for_stack int scrub_stripe(struct scrub_dev *sdev,
 
                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
                 if (ret < 0)
-                        goto out;
-
-                l = path->nodes[0];
-                slot = path->slots[0];
-                btrfs_item_key_to_cpu(l, &key, slot);
-                if (key.objectid != logical) {
-                        ret = btrfs_previous_item(root, path, 0,
-                                                  BTRFS_EXTENT_ITEM_KEY);
-                        if (ret < 0)
-                                goto out;
-                }
+                        goto out_noplug;
 
+                /*
+                 * we might miss half an extent here, but that doesn't matter,
+                 * as it's only the prefetch
+                 */
                 while (1) {
                         l = path->nodes[0];
                         slot = path->slots[0];
@@ -824,7 +812,7 @@ static noinline_for_stack int scrub_stripe(struct scrub_dev *sdev,
                                 if (ret == 0)
                                         continue;
                                 if (ret < 0)
-                                        goto out;
+                                        goto out_noplug;
 
                                 break;
                         }
@@ -906,15 +894,20 @@ again:
                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
                 if (ret < 0)
                         goto out;
-
-                l = path->nodes[0];
-                slot = path->slots[0];
-                btrfs_item_key_to_cpu(l, &key, slot);
-                if (key.objectid != logical) {
+                if (ret > 0) {
                         ret = btrfs_previous_item(root, path, 0,
                                                   BTRFS_EXTENT_ITEM_KEY);
                         if (ret < 0)
                                 goto out;
+                        if (ret > 0) {
+                                /* there's no smaller item, so stick with the
+                                 * larger one */
+                                btrfs_release_path(path);
+                                ret = btrfs_search_slot(NULL, root, &key,
+                                                        path, 0, 0);
+                                if (ret < 0)
+                                        goto out;
+                        }
                 }
 
                 while (1) {
@@ -989,6 +982,7 @@ next:
 
 out:
         blk_finish_plug(&plug);
+out_noplug:
         btrfs_free_path(path);
         return ret < 0 ? ret : 0;
 }
@@ -1064,8 +1058,15 @@ int scrub_enumerate_chunks(struct scrub_dev *sdev, u64 start, u64 end)
         while (1) {
                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
                 if (ret < 0)
-                        goto out;
-                ret = 0;
+                        break;
+                if (ret > 0) {
+                        if (path->slots[0] >=
+                            btrfs_header_nritems(path->nodes[0])) {
+                                ret = btrfs_next_leaf(root, path);
+                                if (ret)
+                                        break;
+                        }
+                }
 
                 l = path->nodes[0];
                 slot = path->slots[0];
@@ -1075,7 +1076,7 @@ int scrub_enumerate_chunks(struct scrub_dev *sdev, u64 start, u64 end)
                 if (found_key.objectid != sdev->dev->devid)
                         break;
 
-                if (btrfs_key_type(&key) != BTRFS_DEV_EXTENT_KEY)
+                if (btrfs_key_type(&found_key) != BTRFS_DEV_EXTENT_KEY)
                         break;
 
                 if (found_key.offset >= end)
@@ -1104,7 +1105,7 @@ int scrub_enumerate_chunks(struct scrub_dev *sdev, u64 start, u64 end)
                 cache = btrfs_lookup_block_group(fs_info, chunk_offset);
                 if (!cache) {
                         ret = -ENOENT;
-                        goto out;
+                        break;
                 }
                 ret = scrub_chunk(sdev, chunk_tree, chunk_objectid,
                                   chunk_offset, length);
@@ -1116,9 +1117,13 @@ int scrub_enumerate_chunks(struct scrub_dev *sdev, u64 start, u64 end)
                 btrfs_release_path(path);
         }
 
-out:
         btrfs_free_path(path);
-        return ret;
+
+        /*
+         * ret can still be 1 from search_slot or next_leaf,
+         * that's not an error
+         */
+        return ret < 0 ? ret : 0;
 }
 
 static noinline_for_stack int scrub_supers(struct scrub_dev *sdev)
@@ -1155,8 +1160,12 @@ static noinline_for_stack int scrub_workers_get(struct btrfs_root *root)
         struct btrfs_fs_info *fs_info = root->fs_info;
 
         mutex_lock(&fs_info->scrub_lock);
-        if (fs_info->scrub_workers_refcnt == 0)
+        if (fs_info->scrub_workers_refcnt == 0) {
+                btrfs_init_workers(&fs_info->scrub_workers, "scrub",
+                           fs_info->thread_pool_size, &fs_info->generic_worker);
+                fs_info->scrub_workers.idle_thresh = 4;
                 btrfs_start_workers(&fs_info->scrub_workers, 1);
+        }
         ++fs_info->scrub_workers_refcnt;
         mutex_unlock(&fs_info->scrub_lock);