Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs

Pull btrfs fixes from Chris Mason:
 "This fixes some lockups in btrfs reported with rc1.  It probably has
  some performance impact because it is backing off our spinning locks
  more often and switching to a blocking lock.  I'll be able to nail
  that down next week, but for now I want to get the lockups taken care
  of.

  Otherwise some more stack reduction and assorted fixes"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs:
  Btrfs: fix wrong error handle when the device is missing or is not writeable
  Btrfs: fix deadlock when mounting a degraded fs
  Btrfs: use bio_endio_nodec instead of open code
  Btrfs: fix NULL pointer crash when running balance and scrub concurrently
  btrfs: Skip scrubbing removed chunks to avoid -ENOENT.
  Btrfs: fix broken free space cache after the system crashed
  Btrfs: make free space cache write out functions more readable
  Btrfs: remove unused wait queue in struct extent_buffer
  Btrfs: fix deadlocks with trylock on tree nodes

11 files changed, 359 insertions, 172 deletions

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index b7e2c1c1ef36..be91397f4e92 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1259,11 +1259,19 @@ struct btrfs_block_group_cache {
         spinlock_t lock;
         u64 pinned;
         u64 reserved;
+        u64 delalloc_bytes;
         u64 bytes_super;
         u64 flags;
         u64 sectorsize;
         u64 cache_generation;
 
+        /*
+         * It is just used for the delayed data space allocation because
+         * only the data space allocation and the relative metadata update
+         * can be done cross the transaction.
+         */
+        struct rw_semaphore data_rwsem;
+
         /* for raid56, this is a full stripe, without parity */
         unsigned long full_stripe_len;
 
@@ -3316,7 +3324,7 @@ int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans,
                                    struct btrfs_key *ins);
 int btrfs_reserve_extent(struct btrfs_root *root, u64 num_bytes,
                          u64 min_alloc_size, u64 empty_size, u64 hint_byte,
-                         struct btrfs_key *ins, int is_data);
+                         struct btrfs_key *ins, int is_data, int delalloc);
 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
                   struct extent_buffer *buf, int full_backref, int no_quota);
 int btrfs_dec_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
@@ -3330,7 +3338,8 @@ int btrfs_free_extent(struct btrfs_trans_handle *trans,
                       u64 bytenr, u64 num_bytes, u64 parent, u64 root_objectid,
                       u64 owner, u64 offset, int no_quota);
 
-int btrfs_free_reserved_extent(struct btrfs_root *root, u64 start, u64 len);
+int btrfs_free_reserved_extent(struct btrfs_root *root, u64 start, u64 len,
+                               int delalloc);
 int btrfs_free_and_pin_reserved_extent(struct btrfs_root *root,
                                        u64 start, u64 len);
 void btrfs_prepare_extent_commit(struct btrfs_trans_handle *trans,
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index fafb3e53ecde..99c253918208 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -105,7 +105,8 @@ static int find_next_key(struct btrfs_path *path, int level,
 static void dump_space_info(struct btrfs_space_info *info, u64 bytes,
                             int dump_block_groups);
 static int btrfs_update_reserved_bytes(struct btrfs_block_group_cache *cache,
-                                       u64 num_bytes, int reserve);
+                                       u64 num_bytes, int reserve,
+                                       int delalloc);
 static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv,
                                u64 num_bytes);
 int btrfs_pin_extent(struct btrfs_root *root,
@@ -3260,7 +3261,8 @@ again:
 
         spin_lock(&block_group->lock);
         if (block_group->cached != BTRFS_CACHE_FINISHED ||
-            !btrfs_test_opt(root, SPACE_CACHE)) {
+            !btrfs_test_opt(root, SPACE_CACHE) ||
+            block_group->delalloc_bytes) {
                 /*
                  * don't bother trying to write stuff out _if_
                  * a) we're not cached,
@@ -5613,6 +5615,7 @@ int btrfs_exclude_logged_extents(struct btrfs_root *log,
  * @cache:      The cache we are manipulating
  * @num_bytes:  The number of bytes in question
  * @reserve:    One of the reservation enums
+ * @delalloc:   The blocks are allocated for the delalloc write
  *
  * This is called by the allocator when it reserves space, or by somebody who is
  * freeing space that was never actually used on disk.  For example if you
@@ -5631,7 +5634,7 @@ int btrfs_exclude_logged_extents(struct btrfs_root *log,
  * succeeds.
  */
 static int btrfs_update_reserved_bytes(struct btrfs_block_group_cache *cache,
-                                       u64 num_bytes, int reserve)
+                                       u64 num_bytes, int reserve, int delalloc)
 {
         struct btrfs_space_info *space_info = cache->space_info;
         int ret = 0;
@@ -5650,12 +5653,18 @@ static int btrfs_update_reserved_bytes(struct btrfs_block_group_cache *cache,
                                                 num_bytes, 0);
                                 space_info->bytes_may_use -= num_bytes;
                         }
+
+                        if (delalloc)
+                                cache->delalloc_bytes += num_bytes;
                 }
         } else {
                 if (cache->ro)
                         space_info->bytes_readonly += num_bytes;
                 cache->reserved -= num_bytes;
                 space_info->bytes_reserved -= num_bytes;
+
+                if (delalloc)
+                        cache->delalloc_bytes -= num_bytes;
         }
         spin_unlock(&cache->lock);
         spin_unlock(&space_info->lock);
@@ -6206,7 +6215,7 @@ void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
                 WARN_ON(test_bit(EXTENT_BUFFER_DIRTY, &buf->bflags));
 
                 btrfs_add_free_space(cache, buf->start, buf->len);
-                btrfs_update_reserved_bytes(cache, buf->len, RESERVE_FREE);
+                btrfs_update_reserved_bytes(cache, buf->len, RESERVE_FREE, 0);
                 trace_btrfs_reserved_extent_free(root, buf->start, buf->len);
                 pin = 0;
         }
@@ -6365,6 +6374,70 @@ enum btrfs_loop_type {
         LOOP_NO_EMPTY_SIZE = 3,
 };
 
+static inline void
+btrfs_lock_block_group(struct btrfs_block_group_cache *cache,
+                       int delalloc)
+{
+        if (delalloc)
+                down_read(&cache->data_rwsem);
+}
+
+static inline void
+btrfs_grab_block_group(struct btrfs_block_group_cache *cache,
+                       int delalloc)
+{
+        btrfs_get_block_group(cache);
+        if (delalloc)
+                down_read(&cache->data_rwsem);
+}
+
+static struct btrfs_block_group_cache *
+btrfs_lock_cluster(struct btrfs_block_group_cache *block_group,
+                   struct btrfs_free_cluster *cluster,
+                   int delalloc)
+{
+        struct btrfs_block_group_cache *used_bg;
+        bool locked = false;
+again:
+        spin_lock(&cluster->refill_lock);
+        if (locked) {
+                if (used_bg == cluster->block_group)
+                        return used_bg;
+
+                up_read(&used_bg->data_rwsem);
+                btrfs_put_block_group(used_bg);
+        }
+
+        used_bg = cluster->block_group;
+        if (!used_bg)
+                return NULL;
+
+        if (used_bg == block_group)
+                return used_bg;
+
+        btrfs_get_block_group(used_bg);
+
+        if (!delalloc)
+                return used_bg;
+
+        if (down_read_trylock(&used_bg->data_rwsem))
+                return used_bg;
+
+        spin_unlock(&cluster->refill_lock);
+        down_read(&used_bg->data_rwsem);
+        locked = true;
+        goto again;
+}
+
+static inline void
+btrfs_release_block_group(struct btrfs_block_group_cache *cache,
+                         int delalloc)
+{
+        if (delalloc)
+                up_read(&cache->data_rwsem);
+        btrfs_put_block_group(cache);
+}
+
 /*
  * walks the btree of allocated extents and find a hole of a given size.
  * The key ins is changed to record the hole:
@@ -6379,7 +6452,7 @@ enum btrfs_loop_type {
 static noinline int find_free_extent(struct btrfs_root *orig_root,
                                      u64 num_bytes, u64 empty_size,
                                      u64 hint_byte, struct btrfs_key *ins,
-                                     u64 flags)
+                                     u64 flags, int delalloc)
 {
         int ret = 0;
         struct btrfs_root *root = orig_root->fs_info->extent_root;
@@ -6467,6 +6540,7 @@ static noinline int find_free_extent(struct btrfs_root *orig_root,
                                 up_read(&space_info->groups_sem);
                         } else {
                                 index = get_block_group_index(block_group);
+                                btrfs_lock_block_group(block_group, delalloc);
                                 goto have_block_group;
                         }
                 } else if (block_group) {
@@ -6481,7 +6555,7 @@ search:
                 u64 offset;
                 int cached;
 
-                btrfs_get_block_group(block_group);
+                btrfs_grab_block_group(block_group, delalloc);
                 search_start = block_group->key.objectid;
 
                 /*
@@ -6529,16 +6603,16 @@ have_block_group:
                          * the refill lock keeps out other
                          * people trying to start a new cluster
                          */
-                        spin_lock(&last_ptr->refill_lock);
-                        used_block_group = last_ptr->block_group;
-                        if (used_block_group != block_group &&
-                            (!used_block_group ||
-                             used_block_group->ro ||
-                             !block_group_bits(used_block_group, flags)))
+                        used_block_group = btrfs_lock_cluster(block_group,
+                                                              last_ptr,
+                                                              delalloc);
+                        if (!used_block_group)
                                 goto refill_cluster;
 
-                        if (used_block_group != block_group)
-                                btrfs_get_block_group(used_block_group);
+                        if (used_block_group != block_group &&
+                            (used_block_group->ro ||
+                             !block_group_bits(used_block_group, flags)))
+                                goto release_cluster;
 
                         offset = btrfs_alloc_from_cluster(used_block_group,
                                                 last_ptr,
@@ -6552,16 +6626,15 @@ have_block_group:
                                                 used_block_group,
                                                 search_start, num_bytes);
                                 if (used_block_group != block_group) {
-                                        btrfs_put_block_group(block_group);
+                                        btrfs_release_block_group(block_group,
+                                                                  delalloc);
                                         block_group = used_block_group;
                                 }
                                 goto checks;
                         }
 
                         WARN_ON(last_ptr->block_group != used_block_group);
-                        if (used_block_group != block_group)
-                                btrfs_put_block_group(used_block_group);
-refill_cluster:
+release_cluster:
                         /* If we are on LOOP_NO_EMPTY_SIZE, we can't
                          * set up a new clusters, so lets just skip it
                          * and let the allocator find whatever block
@@ -6578,8 +6651,10 @@ refill_cluster:
                          * succeeding in the unclustered
                          * allocation.  */
                         if (loop >= LOOP_NO_EMPTY_SIZE &&
-                            last_ptr->block_group != block_group) {
+                            used_block_group != block_group) {
                                 spin_unlock(&last_ptr->refill_lock);
+                                btrfs_release_block_group(used_block_group,
+                                                          delalloc);
                                 goto unclustered_alloc;
                         }
 
@@ -6589,6 +6664,10 @@ refill_cluster:
                          */
                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
 
+                        if (used_block_group != block_group)
+                                btrfs_release_block_group(used_block_group,
+                                                          delalloc);
+refill_cluster:
                         if (loop >= LOOP_NO_EMPTY_SIZE) {
                                 spin_unlock(&last_ptr->refill_lock);
                                 goto unclustered_alloc;
@@ -6696,7 +6775,7 @@ checks:
                 BUG_ON(offset > search_start);
 
                 ret = btrfs_update_reserved_bytes(block_group, num_bytes,
-                                                  alloc_type);
+                                                  alloc_type, delalloc);
                 if (ret == -EAGAIN) {
                         btrfs_add_free_space(block_group, offset, num_bytes);
                         goto loop;
@@ -6708,13 +6787,13 @@ checks:
 
                 trace_btrfs_reserve_extent(orig_root, block_group,
                                            search_start, num_bytes);
-                btrfs_put_block_group(block_group);
+                btrfs_release_block_group(block_group, delalloc);
                 break;
 loop:
                 failed_cluster_refill = false;
                 failed_alloc = false;
                 BUG_ON(index != get_block_group_index(block_group));
-                btrfs_put_block_group(block_group);
+                btrfs_release_block_group(block_group, delalloc);
         }
         up_read(&space_info->groups_sem);
 
@@ -6827,7 +6906,7 @@ again:
 int btrfs_reserve_extent(struct btrfs_root *root,
                          u64 num_bytes, u64 min_alloc_size,
                          u64 empty_size, u64 hint_byte,
-                         struct btrfs_key *ins, int is_data)
+                         struct btrfs_key *ins, int is_data, int delalloc)
 {
         bool final_tried = false;
         u64 flags;
@@ -6837,7 +6916,7 @@ int btrfs_reserve_extent(struct btrfs_root *root,
 again:
         WARN_ON(num_bytes < root->sectorsize);
         ret = find_free_extent(root, num_bytes, empty_size, hint_byte, ins,
-                               flags);
+                               flags, delalloc);
 
         if (ret == -ENOSPC) {
                 if (!final_tried && ins->offset) {
@@ -6862,7 +6941,8 @@ again:
 }
 
 static int __btrfs_free_reserved_extent(struct btrfs_root *root,
-                                        u64 start, u64 len, int pin)
+                                        u64 start, u64 len,
+                                        int pin, int delalloc)
 {
         struct btrfs_block_group_cache *cache;
         int ret = 0;
@@ -6881,7 +6961,7 @@ static int __btrfs_free_reserved_extent(struct btrfs_root *root,
                 pin_down_extent(root, cache, start, len, 1);
         else {
                 btrfs_add_free_space(cache, start, len);
-                btrfs_update_reserved_bytes(cache, len, RESERVE_FREE);
+                btrfs_update_reserved_bytes(cache, len, RESERVE_FREE, delalloc);
         }
         btrfs_put_block_group(cache);
 
@@ -6891,15 +6971,15 @@ static int __btrfs_free_reserved_extent(struct btrfs_root *root,
 }
 
 int btrfs_free_reserved_extent(struct btrfs_root *root,
-                                        u64 start, u64 len)
+                               u64 start, u64 len, int delalloc)
 {
-        return __btrfs_free_reserved_extent(root, start, len, 0);
+        return __btrfs_free_reserved_extent(root, start, len, 0, delalloc);
 }
 
 int btrfs_free_and_pin_reserved_extent(struct btrfs_root *root,
                                        u64 start, u64 len)
 {
-        return __btrfs_free_reserved_extent(root, start, len, 1);
+        return __btrfs_free_reserved_extent(root, start, len, 1, 0);
 }
 
 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
@@ -7114,7 +7194,7 @@ int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans,
                 return -EINVAL;
 
         ret = btrfs_update_reserved_bytes(block_group, ins->offset,
-                                          RESERVE_ALLOC_NO_ACCOUNT);
+                                          RESERVE_ALLOC_NO_ACCOUNT, 0);
         BUG_ON(ret); /* logic error */
         ret = alloc_reserved_file_extent(trans, root, 0, root_objectid,
                                          0, owner, offset, ins, 1);
@@ -7256,7 +7336,7 @@ struct extent_buffer *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
                 return ERR_CAST(block_rsv);
 
         ret = btrfs_reserve_extent(root, blocksize, blocksize,
-                                   empty_size, hint, &ins, 0);
+                                   empty_size, hint, &ins, 0, 0);
         if (ret) {
                 unuse_block_rsv(root->fs_info, block_rsv, blocksize);
                 return ERR_PTR(ret);
@@ -8659,6 +8739,7 @@ btrfs_create_block_group_cache(struct btrfs_root *root, u64 start, u64 size)
                                                start);
         atomic_set(&cache->count, 1);
         spin_lock_init(&cache->lock);
+        init_rwsem(&cache->data_rwsem);
         INIT_LIST_HEAD(&cache->list);
         INIT_LIST_HEAD(&cache->cluster_list);
         INIT_LIST_HEAD(&cache->new_bg_list);
diff --git a/fs/btrfs/extent_io.h b/fs/btrfs/extent_io.h
index 15ce5f2a2b62..ccc264e7bde1 100644
--- a/fs/btrfs/extent_io.h
+++ b/fs/btrfs/extent_io.h
@@ -158,7 +158,6 @@ struct extent_buffer {
          * to unlock
          */
         wait_queue_head_t read_lock_wq;
-        wait_queue_head_t lock_wq;
         struct page *pages[INLINE_EXTENT_BUFFER_PAGES];
 #ifdef CONFIG_BTRFS_DEBUG
         struct list_head leak_list;
diff --git a/fs/btrfs/extent_map.c b/fs/btrfs/extent_map.c
index 1874aee69c86..225302b39afb 100644
--- a/fs/btrfs/extent_map.c
+++ b/fs/btrfs/extent_map.c
@@ -75,6 +75,8 @@ void free_extent_map(struct extent_map *em)
         if (atomic_dec_and_test(&em->refs)) {
                 WARN_ON(extent_map_in_tree(em));
                 WARN_ON(!list_empty(&em->list));
+                if (test_bit(EXTENT_FLAG_FS_MAPPING, &em->flags))
+                        kfree(em->bdev);
                 kmem_cache_free(extent_map_cache, em);
         }
 }
diff --git a/fs/btrfs/extent_map.h b/fs/btrfs/extent_map.h
index e7fd8a56a140..b2991fd8583e 100644
--- a/fs/btrfs/extent_map.h
+++ b/fs/btrfs/extent_map.h
@@ -15,6 +15,7 @@
 #define EXTENT_FLAG_PREALLOC 3 /* pre-allocated extent */
 #define EXTENT_FLAG_LOGGING 4 /* Logging this extent */
 #define EXTENT_FLAG_FILLING 5 /* Filling in a preallocated extent */
+#define EXTENT_FLAG_FS_MAPPING 6 /* filesystem extent mapping type */
 
 struct extent_map {
         struct rb_node rb_node;
diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c
index 372b05ff1943..2b0a627cb5f9 100644
--- a/fs/btrfs/free-space-cache.c
+++ b/fs/btrfs/free-space-cache.c
@@ -274,18 +274,32 @@ struct io_ctl {
 };
 
 static int io_ctl_init(struct io_ctl *io_ctl, struct inode *inode,
-                       struct btrfs_root *root)
+                       struct btrfs_root *root, int write)
 {
+        int num_pages;
+        int check_crcs = 0;
+
+        num_pages = (i_size_read(inode) + PAGE_CACHE_SIZE - 1) >>
+                    PAGE_CACHE_SHIFT;
+
+        if (btrfs_ino(inode) != BTRFS_FREE_INO_OBJECTID)
+                check_crcs = 1;
+
+        /* Make sure we can fit our crcs into the first page */
+        if (write && check_crcs &&
+            (num_pages * sizeof(u32)) >= PAGE_CACHE_SIZE)
+                return -ENOSPC;
+
         memset(io_ctl, 0, sizeof(struct io_ctl));
-        io_ctl->num_pages = (i_size_read(inode) + PAGE_CACHE_SIZE - 1) >>
-                PAGE_CACHE_SHIFT;
-        io_ctl->pages = kzalloc(sizeof(struct page *) * io_ctl->num_pages,
-                                GFP_NOFS);
+
+        io_ctl->pages = kzalloc(sizeof(struct page *) * num_pages, GFP_NOFS);
         if (!io_ctl->pages)
                 return -ENOMEM;
+
+        io_ctl->num_pages = num_pages;
         io_ctl->root = root;
-        if (btrfs_ino(inode) != BTRFS_FREE_INO_OBJECTID)
-                io_ctl->check_crcs = 1;
+        io_ctl->check_crcs = check_crcs;
+
         return 0;
 }
 
@@ -666,6 +680,13 @@ static int __load_free_space_cache(struct btrfs_root *root, struct inode *inode,
         generation = btrfs_free_space_generation(leaf, header);
         btrfs_release_path(path);
 
+        if (!BTRFS_I(inode)->generation) {
+                btrfs_info(root->fs_info,
+                           "The free space cache file (%llu) is invalid. skip it\n",
+                           offset);
+                return 0;
+        }
+
         if (BTRFS_I(inode)->generation != generation) {
                 btrfs_err(root->fs_info,
                         "free space inode generation (%llu) "
@@ -677,7 +698,7 @@ static int __load_free_space_cache(struct btrfs_root *root, struct inode *inode,
         if (!num_entries)
                 return 0;
 
-        ret = io_ctl_init(&io_ctl, inode, root);
+        ret = io_ctl_init(&io_ctl, inode, root, 0);
         if (ret)
                 return ret;
 
@@ -957,19 +978,18 @@ fail:
 }
 
 static noinline_for_stack int
-add_ioctl_entries(struct btrfs_root *root,
-                  struct inode *inode,
-                  struct btrfs_block_group_cache *block_group,
-                  struct io_ctl *io_ctl,
-                  struct extent_state **cached_state,
-                  struct list_head *bitmap_list,
-                  int *entries)
+write_pinned_extent_entries(struct btrfs_root *root,
+                            struct btrfs_block_group_cache *block_group,
+                            struct io_ctl *io_ctl,
+                            int *entries)
 {
         u64 start, extent_start, extent_end, len;
-        struct list_head *pos, *n;
         struct extent_io_tree *unpin = NULL;
         int ret;
 
+        if (!block_group)
+                return 0;
+
         /*
          * We want to add any pinned extents to our free space cache
          * so we don't leak the space
@@ -979,23 +999,19 @@ add_ioctl_entries(struct btrfs_root *root,
          */
         unpin = root->fs_info->pinned_extents;
 
-        if (block_group)
-                start = block_group->key.objectid;
+        start = block_group->key.objectid;
 
-        while (block_group && (start < block_group->key.objectid +
-                               block_group->key.offset)) {
+        while (start < block_group->key.objectid + block_group->key.offset) {
                 ret = find_first_extent_bit(unpin, start,
                                             &extent_start, &extent_end,
                                             EXTENT_DIRTY, NULL);
-                if (ret) {
-                        ret = 0;
-                        break;
-                }
+                if (ret)
+                        return 0;
 
                 /* This pinned extent is out of our range */
                 if (extent_start >= block_group->key.objectid +
                     block_group->key.offset)
-                        break;
+                        return 0;
 
                 extent_start = max(extent_start, start);
                 extent_end = min(block_group->key.objectid +
@@ -1005,11 +1021,20 @@ add_ioctl_entries(struct btrfs_root *root,
                 *entries += 1;
                 ret = io_ctl_add_entry(io_ctl, extent_start, len, NULL);
                 if (ret)
-                        goto out_nospc;
+                        return -ENOSPC;
 
                 start = extent_end;
         }
 
+        return 0;
+}
+
+static noinline_for_stack int
+write_bitmap_entries(struct io_ctl *io_ctl, struct list_head *bitmap_list)
+{
+        struct list_head *pos, *n;
+        int ret;
+
         /* Write out the bitmaps */
         list_for_each_safe(pos, n, bitmap_list) {
                 struct btrfs_free_space *entry =
@@ -1017,36 +1042,24 @@ add_ioctl_entries(struct btrfs_root *root,
 
                 ret = io_ctl_add_bitmap(io_ctl, entry->bitmap);
                 if (ret)
-                        goto out_nospc;
+                        return -ENOSPC;
                 list_del_init(&entry->list);
         }
 
-        /* Zero out the rest of the pages just to make sure */
-        io_ctl_zero_remaining_pages(io_ctl);
-
-        ret = btrfs_dirty_pages(root, inode, io_ctl->pages, io_ctl->num_pages,
-                                0, i_size_read(inode), cached_state);
-        io_ctl_drop_pages(io_ctl);
-        unlock_extent_cached(&BTRFS_I(inode)->io_tree, 0,
-                             i_size_read(inode) - 1, cached_state, GFP_NOFS);
+        return 0;
+}
 
-        if (ret)
-                goto fail;
+static int flush_dirty_cache(struct inode *inode)
+{
+        int ret;
 
         ret = btrfs_wait_ordered_range(inode, 0, (u64)-1);
-        if (ret) {
+        if (ret)
                 clear_extent_bit(&BTRFS_I(inode)->io_tree, 0, inode->i_size - 1,
                                  EXTENT_DIRTY | EXTENT_DELALLOC, 0, 0, NULL,
                                  GFP_NOFS);
-                goto fail;
-        }
-        return 0;
 
-fail:
-        return -1;
-
-out_nospc:
-        return -ENOSPC;
+        return ret;
 }
 
 static void noinline_for_stack
@@ -1056,6 +1069,7 @@ cleanup_write_cache_enospc(struct inode *inode,
                            struct list_head *bitmap_list)
 {
         struct list_head *pos, *n;
+
         list_for_each_safe(pos, n, bitmap_list) {
                 struct btrfs_free_space *entry =
                         list_entry(pos, struct btrfs_free_space, list);
@@ -1088,64 +1102,104 @@ static int __btrfs_write_out_cache(struct btrfs_root *root, struct inode *inode,
 {
         struct extent_state *cached_state = NULL;
         struct io_ctl io_ctl;
-        struct list_head bitmap_list;
+        LIST_HEAD(bitmap_list);
         int entries = 0;
         int bitmaps = 0;
         int ret;
-        int err = -1;
-
-        INIT_LIST_HEAD(&bitmap_list);
 
         if (!i_size_read(inode))
                 return -1;
 
-        ret = io_ctl_init(&io_ctl, inode, root);
+        ret = io_ctl_init(&io_ctl, inode, root, 1);
         if (ret)
                 return -1;
 
+        if (block_group && (block_group->flags & BTRFS_BLOCK_GROUP_DATA)) {
+                down_write(&block_group->data_rwsem);
+                spin_lock(&block_group->lock);
+                if (block_group->delalloc_bytes) {
+                        block_group->disk_cache_state = BTRFS_DC_WRITTEN;
+                        spin_unlock(&block_group->lock);
+                        up_write(&block_group->data_rwsem);
+                        BTRFS_I(inode)->generation = 0;
+                        ret = 0;
+                        goto out;
+                }
+                spin_unlock(&block_group->lock);
+        }
+
         /* Lock all pages first so we can lock the extent safely. */
         io_ctl_prepare_pages(&io_ctl, inode, 0);
 
         lock_extent_bits(&BTRFS_I(inode)->io_tree, 0, i_size_read(inode) - 1,
                          0, &cached_state);
 
-
-        /* Make sure we can fit our crcs into the first page */
-        if (io_ctl.check_crcs &&
-            (io_ctl.num_pages * sizeof(u32)) >= PAGE_CACHE_SIZE)
-                goto out_nospc;
-
         io_ctl_set_generation(&io_ctl, trans->transid);
 
+        /* Write out the extent entries in the free space cache */
         ret = write_cache_extent_entries(&io_ctl, ctl,
                                          block_group, &entries, &bitmaps,
                                          &bitmap_list);
         if (ret)
                 goto out_nospc;
 
-        ret = add_ioctl_entries(root, inode, block_group, &io_ctl,
-                                &cached_state, &bitmap_list, &entries);
+        /*
+         * Some spaces that are freed in the current transaction are pinned,
+         * they will be added into free space cache after the transaction is
+         * committed, we shouldn't lose them.
+         */
+        ret = write_pinned_extent_entries(root, block_group, &io_ctl, &entries);
+        if (ret)
+                goto out_nospc;
 
-        if (ret == -ENOSPC)
+        /* At last, we write out all the bitmaps. */
+        ret = write_bitmap_entries(&io_ctl, &bitmap_list);
+        if (ret)
                 goto out_nospc;
-        else if (ret)
+
+        /* Zero out the rest of the pages just to make sure */
+        io_ctl_zero_remaining_pages(&io_ctl);
+
+        /* Everything is written out, now we dirty the pages in the file. */
+        ret = btrfs_dirty_pages(root, inode, io_ctl.pages, io_ctl.num_pages,
+                                0, i_size_read(inode), &cached_state);
+        if (ret)
+                goto out_nospc;
+
+        if (block_group && (block_group->flags & BTRFS_BLOCK_GROUP_DATA))
+                up_write(&block_group->data_rwsem);
+        /*
+         * Release the pages and unlock the extent, we will flush
+         * them out later
+         */
+        io_ctl_drop_pages(&io_ctl);
+
+        unlock_extent_cached(&BTRFS_I(inode)->io_tree, 0,
+                             i_size_read(inode) - 1, &cached_state, GFP_NOFS);
+
+        /* Flush the dirty pages in the cache file. */
+        ret = flush_dirty_cache(inode);
+        if (ret)
                 goto out;
 
-        err = update_cache_item(trans, root, inode, path, offset,
+        /* Update the cache item to tell everyone this cache file is valid. */
+        ret = update_cache_item(trans, root, inode, path, offset,
                                 entries, bitmaps);
-
 out:
         io_ctl_free(&io_ctl);
-        if (err) {
+        if (ret) {
                 invalidate_inode_pages2(inode->i_mapping);
                 BTRFS_I(inode)->generation = 0;
         }
         btrfs_update_inode(trans, root, inode);
-        return err;
+        return ret;
 
 out_nospc:
-
         cleanup_write_cache_enospc(inode, &io_ctl, &cached_state, &bitmap_list);
+
+        if (block_group && (block_group->flags & BTRFS_BLOCK_GROUP_DATA))
+                up_write(&block_group->data_rwsem);
+
         goto out;
 }
 
@@ -1165,6 +1219,12 @@ int btrfs_write_out_cache(struct btrfs_root *root,
                 spin_unlock(&block_group->lock);
                 return 0;
         }
+
+        if (block_group->delalloc_bytes) {
+                block_group->disk_cache_state = BTRFS_DC_WRITTEN;
+                spin_unlock(&block_group->lock);
+                return 0;
+        }
         spin_unlock(&block_group->lock);
 
         inode = lookup_free_space_inode(root, block_group, path);
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 8925f66a1411..3668048e16f8 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -693,7 +693,7 @@ retry:
                 ret = btrfs_reserve_extent(root,
                                            async_extent->compressed_size,
                                            async_extent->compressed_size,
-                                           0, alloc_hint, &ins, 1);
+                                           0, alloc_hint, &ins, 1, 1);
                 if (ret) {
                         int i;
 
@@ -794,7 +794,7 @@ retry:
 out:
         return ret;
 out_free_reserve:
-        btrfs_free_reserved_extent(root, ins.objectid, ins.offset);
+        btrfs_free_reserved_extent(root, ins.objectid, ins.offset, 1);
 out_free:
         extent_clear_unlock_delalloc(inode, async_extent->start,
                                      async_extent->start +
@@ -917,7 +917,7 @@ static noinline int cow_file_range(struct inode *inode,
                 cur_alloc_size = disk_num_bytes;
                 ret = btrfs_reserve_extent(root, cur_alloc_size,
                                            root->sectorsize, 0, alloc_hint,
-                                           &ins, 1);
+                                           &ins, 1, 1);
                 if (ret < 0)
                         goto out_unlock;
 
@@ -995,7 +995,7 @@ out:
         return ret;
 
 out_reserve:
-        btrfs_free_reserved_extent(root, ins.objectid, ins.offset);
+        btrfs_free_reserved_extent(root, ins.objectid, ins.offset, 1);
 out_unlock:
         extent_clear_unlock_delalloc(inode, start, end, locked_page,
                                      EXTENT_LOCKED | EXTENT_DO_ACCOUNTING |
@@ -2599,6 +2599,21 @@ out_kfree:
         return NULL;
 }
 
+static void btrfs_release_delalloc_bytes(struct btrfs_root *root,
+                                         u64 start, u64 len)
+{
+        struct btrfs_block_group_cache *cache;
+
+        cache = btrfs_lookup_block_group(root->fs_info, start);
+        ASSERT(cache);
+
+        spin_lock(&cache->lock);
+        cache->delalloc_bytes -= len;
+        spin_unlock(&cache->lock);
+
+        btrfs_put_block_group(cache);
+}
+
 /* as ordered data IO finishes, this gets called so we can finish
  * an ordered extent if the range of bytes in the file it covers are
  * fully written.
@@ -2698,6 +2713,10 @@ static int btrfs_finish_ordered_io(struct btrfs_ordered_extent *ordered_extent)
                                                 logical_len, logical_len,
                                                 compress_type, 0, 0,
                                                 BTRFS_FILE_EXTENT_REG);
+                if (!ret)
+                        btrfs_release_delalloc_bytes(root,
+                                                     ordered_extent->start,
+                                                     ordered_extent->disk_len);
         }
         unpin_extent_cache(&BTRFS_I(inode)->extent_tree,
                            ordered_extent->file_offset, ordered_extent->len,
@@ -2750,7 +2769,7 @@ out:
                     !test_bit(BTRFS_ORDERED_NOCOW, &ordered_extent->flags) &&
                     !test_bit(BTRFS_ORDERED_PREALLOC, &ordered_extent->flags))
                         btrfs_free_reserved_extent(root, ordered_extent->start,
-                                                   ordered_extent->disk_len);
+                                                   ordered_extent->disk_len, 1);
         }
 
 
@@ -6535,21 +6554,21 @@ static struct extent_map *btrfs_new_extent_direct(struct inode *inode,
 
         alloc_hint = get_extent_allocation_hint(inode, start, len);
         ret = btrfs_reserve_extent(root, len, root->sectorsize, 0,
-                                   alloc_hint, &ins, 1);
+                                   alloc_hint, &ins, 1, 1);
         if (ret)
                 return ERR_PTR(ret);
 
         em = create_pinned_em(inode, start, ins.offset, start, ins.objectid,
                               ins.offset, ins.offset, ins.offset, 0);
         if (IS_ERR(em)) {
-                btrfs_free_reserved_extent(root, ins.objectid, ins.offset);
+                btrfs_free_reserved_extent(root, ins.objectid, ins.offset, 1);
                 return em;
         }
 
         ret = btrfs_add_ordered_extent_dio(inode, start, ins.objectid,
                                            ins.offset, ins.offset, 0);
         if (ret) {
-                btrfs_free_reserved_extent(root, ins.objectid, ins.offset);
+                btrfs_free_reserved_extent(root, ins.objectid, ins.offset, 1);
                 free_extent_map(em);
                 return ERR_PTR(ret);
         }
@@ -7437,7 +7456,7 @@ free_ordered:
                 if (!test_bit(BTRFS_ORDERED_PREALLOC, &ordered->flags) &&
                     !test_bit(BTRFS_ORDERED_NOCOW, &ordered->flags))
                         btrfs_free_reserved_extent(root, ordered->start,
-                                                   ordered->disk_len);
+                                                   ordered->disk_len, 1);
                 btrfs_put_ordered_extent(ordered);
                 btrfs_put_ordered_extent(ordered);
         }
@@ -8808,7 +8827,7 @@ static int __btrfs_prealloc_file_range(struct inode *inode, int mode,
                 cur_bytes = min(num_bytes, 256ULL * 1024 * 1024);
                 cur_bytes = max(cur_bytes, min_size);
                 ret = btrfs_reserve_extent(root, cur_bytes, min_size, 0,
-                                           *alloc_hint, &ins, 1);
+                                           *alloc_hint, &ins, 1, 0);
                 if (ret) {
                         if (own_trans)
                                 btrfs_end_transaction(trans, root);
@@ -8822,7 +8841,7 @@ static int __btrfs_prealloc_file_range(struct inode *inode, int mode,
                                                   BTRFS_FILE_EXTENT_PREALLOC);
                 if (ret) {
                         btrfs_free_reserved_extent(root, ins.objectid,
-                                                   ins.offset);
+                                                   ins.offset, 0);
                         btrfs_abort_transaction(trans, root, ret);
                         if (own_trans)
                                 btrfs_end_transaction(trans, root);
diff --git a/fs/btrfs/locking.c b/fs/btrfs/locking.c
index 01277b8f2373..5665d2149249 100644
--- a/fs/btrfs/locking.c
+++ b/fs/btrfs/locking.c
@@ -33,14 +33,14 @@ static void btrfs_assert_tree_read_locked(struct extent_buffer *eb);
  */
 void btrfs_set_lock_blocking_rw(struct extent_buffer *eb, int rw)
 {
-        if (eb->lock_nested) {
-                read_lock(&eb->lock);
-                if (eb->lock_nested && current->pid == eb->lock_owner) {
-                        read_unlock(&eb->lock);
-                        return;
-                }
-                read_unlock(&eb->lock);
-        }
+        /*
+         * no lock is required.  The lock owner may change if
+         * we have a read lock, but it won't change to or away
+         * from us.  If we have the write lock, we are the owner
+         * and it'll never change.
+         */
+        if (eb->lock_nested && current->pid == eb->lock_owner)
+                return;
         if (rw == BTRFS_WRITE_LOCK) {
                 if (atomic_read(&eb->blocking_writers) == 0) {
                         WARN_ON(atomic_read(&eb->spinning_writers) != 1);
@@ -65,14 +65,15 @@ void btrfs_set_lock_blocking_rw(struct extent_buffer *eb, int rw)
  */
 void btrfs_clear_lock_blocking_rw(struct extent_buffer *eb, int rw)
 {
-        if (eb->lock_nested) {
-                read_lock(&eb->lock);
-                if (eb->lock_nested && current->pid == eb->lock_owner) {
-                        read_unlock(&eb->lock);
-                        return;
-                }
-                read_unlock(&eb->lock);
-        }
+        /*
+         * no lock is required.  The lock owner may change if
+         * we have a read lock, but it won't change to or away
+         * from us.  If we have the write lock, we are the owner
+         * and it'll never change.
+         */
+        if (eb->lock_nested && current->pid == eb->lock_owner)
+                return;
+
         if (rw == BTRFS_WRITE_LOCK_BLOCKING) {
                 BUG_ON(atomic_read(&eb->blocking_writers) != 1);
                 write_lock(&eb->lock);
@@ -99,6 +100,9 @@ void btrfs_clear_lock_blocking_rw(struct extent_buffer *eb, int rw)
 void btrfs_tree_read_lock(struct extent_buffer *eb)
 {
 again:
+        BUG_ON(!atomic_read(&eb->blocking_writers) &&
+               current->pid == eb->lock_owner);
+
         read_lock(&eb->lock);
         if (atomic_read(&eb->blocking_writers) &&
             current->pid == eb->lock_owner) {
@@ -132,7 +136,9 @@ int btrfs_try_tree_read_lock(struct extent_buffer *eb)
         if (atomic_read(&eb->blocking_writers))
                 return 0;
 
-        read_lock(&eb->lock);
+        if (!read_trylock(&eb->lock))
+                return 0;
+
         if (atomic_read(&eb->blocking_writers)) {
                 read_unlock(&eb->lock);
                 return 0;
@@ -151,7 +157,10 @@ int btrfs_try_tree_write_lock(struct extent_buffer *eb)
         if (atomic_read(&eb->blocking_writers) ||
             atomic_read(&eb->blocking_readers))
                 return 0;
-        write_lock(&eb->lock);
+
+        if (!write_trylock(&eb->lock))
+                return 0;
+
         if (atomic_read(&eb->blocking_writers) ||
             atomic_read(&eb->blocking_readers)) {
                 write_unlock(&eb->lock);
@@ -168,14 +177,15 @@ int btrfs_try_tree_write_lock(struct extent_buffer *eb)
  */
 void btrfs_tree_read_unlock(struct extent_buffer *eb)
 {
-        if (eb->lock_nested) {
-                read_lock(&eb->lock);
-                if (eb->lock_nested && current->pid == eb->lock_owner) {
-                        eb->lock_nested = 0;
-                        read_unlock(&eb->lock);
-                        return;
-                }
-                read_unlock(&eb->lock);
+        /*
+         * if we're nested, we have the write lock.  No new locking
+         * is needed as long as we are the lock owner.
+         * The write unlock will do a barrier for us, and the lock_nested
+         * field only matters to the lock owner.
+         */
+        if (eb->lock_nested && current->pid == eb->lock_owner) {
+                eb->lock_nested = 0;
+                return;
         }
         btrfs_assert_tree_read_locked(eb);
         WARN_ON(atomic_read(&eb->spinning_readers) == 0);
@@ -189,14 +199,15 @@ void btrfs_tree_read_unlock(struct extent_buffer *eb)
  */
 void btrfs_tree_read_unlock_blocking(struct extent_buffer *eb)
 {
-        if (eb->lock_nested) {
-                read_lock(&eb->lock);
-                if (eb->lock_nested && current->pid == eb->lock_owner) {
-                        eb->lock_nested = 0;
-                        read_unlock(&eb->lock);
-                        return;
-                }
-                read_unlock(&eb->lock);
+        /*
+         * if we're nested, we have the write lock.  No new locking
+         * is needed as long as we are the lock owner.
+         * The write unlock will do a barrier for us, and the lock_nested
+         * field only matters to the lock owner.
+         */
+        if (eb->lock_nested && current->pid == eb->lock_owner) {
+                eb->lock_nested = 0;
+                return;
         }
         btrfs_assert_tree_read_locked(eb);
         WARN_ON(atomic_read(&eb->blocking_readers) == 0);
@@ -244,6 +255,7 @@ void btrfs_tree_unlock(struct extent_buffer *eb)
         BUG_ON(blockers > 1);
 
         btrfs_assert_tree_locked(eb);
+        eb->lock_owner = 0;
         atomic_dec(&eb->write_locks);
 
         if (blockers) {
diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
index ac80188eec88..b6d198f5181e 100644
--- a/fs/btrfs/scrub.c
+++ b/fs/btrfs/scrub.c
@@ -2725,11 +2725,8 @@ int scrub_enumerate_chunks(struct scrub_ctx *sctx,
                 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
                 length = btrfs_dev_extent_length(l, dev_extent);
 
-                if (found_key.offset + length <= start) {
-                        key.offset = found_key.offset + length;
-                        btrfs_release_path(path);
-                        continue;
-                }
+                if (found_key.offset + length <= start)
+                        goto skip;
 
                 chunk_tree = btrfs_dev_extent_chunk_tree(l, dev_extent);
                 chunk_objectid = btrfs_dev_extent_chunk_objectid(l, dev_extent);
@@ -2740,10 +2737,12 @@ int scrub_enumerate_chunks(struct scrub_ctx *sctx,
                  * the chunk from going away while we scrub it
                  */
                 cache = btrfs_lookup_block_group(fs_info, chunk_offset);
-                if (!cache) {
-                        ret = -ENOENT;
-                        break;
-                }
+
+                /* some chunks are removed but not committed to disk yet,
+                 * continue scrubbing */
+                if (!cache)
+                        goto skip;
+
                 dev_replace->cursor_right = found_key.offset + length;
                 dev_replace->cursor_left = found_key.offset;
                 dev_replace->item_needs_writeback = 1;
@@ -2802,7 +2801,7 @@ int scrub_enumerate_chunks(struct scrub_ctx *sctx,
 
                 dev_replace->cursor_left = dev_replace->cursor_right;
                 dev_replace->item_needs_writeback = 1;
-
+skip:
                 key.offset = found_key.offset + length;
                 btrfs_release_path(path);
         }
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index ffeed6d6326f..c83b24251e53 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -2543,9 +2543,6 @@ static int btrfs_relocate_chunk(struct btrfs_root *root,
         remove_extent_mapping(em_tree, em);
         write_unlock(&em_tree->lock);
 
-        kfree(map);
-        em->bdev = NULL;
-
         /* once for the tree */
         free_extent_map(em);
         /* once for us */
@@ -4301,9 +4298,11 @@ static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
 
         em = alloc_extent_map();
         if (!em) {
+                kfree(map);
                 ret = -ENOMEM;
                 goto error;
         }
+        set_bit(EXTENT_FLAG_FS_MAPPING, &em->flags);
         em->bdev = (struct block_device *)map;
         em->start = start;
         em->len = num_bytes;
@@ -4346,7 +4345,6 @@ error_del_extent:
         /* One for the tree reference */
         free_extent_map(em);
 error:
-        kfree(map);
         kfree(devices_info);
         return ret;
 }
@@ -4558,7 +4556,6 @@ void btrfs_mapping_tree_free(struct btrfs_mapping_tree *tree)
                 write_unlock(&tree->map_tree.lock);
                 if (!em)
                         break;
-                kfree(em->bdev);
                 /* once for us */
                 free_extent_map(em);
                 /* once for the tree */
@@ -5362,6 +5359,15 @@ int btrfs_rmap_block(struct btrfs_mapping_tree *map_tree,
         return 0;
 }
 
+static inline void btrfs_end_bbio(struct btrfs_bio *bbio, struct bio *bio, int err)
+{
+        if (likely(bbio->flags & BTRFS_BIO_ORIG_BIO_SUBMITTED))
+                bio_endio_nodec(bio, err);
+        else
+                bio_endio(bio, err);
+        kfree(bbio);
+}
+
 static void btrfs_end_bio(struct bio *bio, int err)
 {
         struct btrfs_bio *bbio = bio->bi_private;
@@ -5402,12 +5408,6 @@ static void btrfs_end_bio(struct bio *bio, int err)
                         bio = bbio->orig_bio;
                 }
 
-                /*
-                 * We have original bio now. So increment bi_remaining to
-                 * account for it in endio
-                 */
-                atomic_inc(&bio->bi_remaining);
-
                 bio->bi_private = bbio->private;
                 bio->bi_end_io = bbio->end_io;
                 btrfs_io_bio(bio)->mirror_num = bbio->mirror_num;
@@ -5424,9 +5424,8 @@ static void btrfs_end_bio(struct bio *bio, int err)
                         set_bit(BIO_UPTODATE, &bio->bi_flags);
                         err = 0;
                 }
-                kfree(bbio);
 
-                bio_endio(bio, err);
+                btrfs_end_bbio(bbio, bio, err);
         } else if (!is_orig_bio) {
                 bio_put(bio);
         }
@@ -5589,12 +5588,15 @@ static void bbio_error(struct btrfs_bio *bbio, struct bio *bio, u64 logical)
 {
         atomic_inc(&bbio->error);
         if (atomic_dec_and_test(&bbio->stripes_pending)) {
+                /* Shoud be the original bio. */
+                WARN_ON(bio != bbio->orig_bio);
+
                 bio->bi_private = bbio->private;
                 bio->bi_end_io = bbio->end_io;
                 btrfs_io_bio(bio)->mirror_num = bbio->mirror_num;
                 bio->bi_iter.bi_sector = logical >> 9;
-                kfree(bbio);
-                bio_endio(bio, -EIO);
+
+                btrfs_end_bbio(bbio, bio, -EIO);
         }
 }
 
@@ -5681,6 +5683,7 @@ int btrfs_map_bio(struct btrfs_root *root, int rw, struct bio *bio,
                         BUG_ON(!bio); /* -ENOMEM */
                 } else {
                         bio = first_bio;
+                        bbio->flags |= BTRFS_BIO_ORIG_BIO_SUBMITTED;
                 }
 
                 submit_stripe_bio(root, bbio, bio,
@@ -5822,6 +5825,7 @@ static int read_one_chunk(struct btrfs_root *root, struct btrfs_key *key,
                 return -ENOMEM;
         }
 
+        set_bit(EXTENT_FLAG_FS_MAPPING, &em->flags);
         em->bdev = (struct block_device *)map;
         em->start = logical;
         em->len = length;
@@ -5846,7 +5850,6 @@ static int read_one_chunk(struct btrfs_root *root, struct btrfs_key *key,
                 map->stripes[i].dev = btrfs_find_device(root->fs_info, devid,
                                                         uuid, NULL);
                 if (!map->stripes[i].dev && !btrfs_test_opt(root, DEGRADED)) {
-                        kfree(map);
                         free_extent_map(em);
                         return -EIO;
                 }
@@ -5854,7 +5857,6 @@ static int read_one_chunk(struct btrfs_root *root, struct btrfs_key *key,
                         map->stripes[i].dev =
                                 add_missing_dev(root, devid, uuid);
                         if (!map->stripes[i].dev) {
-                                kfree(map);
                                 free_extent_map(em);
                                 return -EIO;
                         }
diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index 1a15bbeb65e2..2aaa00c47816 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -190,11 +190,14 @@ struct btrfs_bio_stripe {
 struct btrfs_bio;
 typedef void (btrfs_bio_end_io_t) (struct btrfs_bio *bio, int err);
 
+#define BTRFS_BIO_ORIG_BIO_SUBMITTED    0x1
+
 struct btrfs_bio {
         atomic_t stripes_pending;
         struct btrfs_fs_info *fs_info;
         bio_end_io_t *end_io;
         struct bio *orig_bio;
+        unsigned long flags;
         void *private;
         atomic_t error;
         int max_errors;