2 files changed, 66 insertions, 5 deletions

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 76e4983b39ea..b528a5509cb8 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1102,6 +1102,18 @@ struct btrfs_space_info {
                                    account */
 
         /*
+         * bytes_pinned is kept in line with what is actually pinned, as in
+         * we've called update_block_group and dropped the bytes_used counter
+         * and increased the bytes_pinned counter.  However this means that
+         * bytes_pinned does not reflect the bytes that will be pinned once the
+         * delayed refs are flushed, so this counter is inc'ed everytime we call
+         * btrfs_free_extent so it is a realtime count of what will be freed
+         * once the transaction is committed.  It will be zero'ed everytime the
+         * transaction commits.
+         */
+        struct percpu_counter total_bytes_pinned;
+
+        /*
          * we bump reservation progress every time we decrement
          * bytes_reserved.  This way people waiting for reservations
          * know something good has happened and they can check
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 6d5c5f73ad64..bbd3db7d0833 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -24,6 +24,7 @@
 #include <linux/kthread.h>
 #include <linux/slab.h>
 #include <linux/ratelimit.h>
+#include <linux/percpu_counter.h>
 #include "compat.h"
 #include "hash.h"
 #include "ctree.h"
@@ -3357,6 +3358,7 @@ static int update_space_info(struct btrfs_fs_info *info, u64 flags,
         struct btrfs_space_info *found;
         int i;
         int factor;
+        int ret;
 
         if (flags & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1 |
                      BTRFS_BLOCK_GROUP_RAID10))
@@ -3380,6 +3382,12 @@ static int update_space_info(struct btrfs_fs_info *info, u64 flags,
         if (!found)
                 return -ENOMEM;
 
+        ret = percpu_counter_init(&found->total_bytes_pinned, 0);
+        if (ret) {
+                kfree(found);
+                return ret;
+        }
+
         for (i = 0; i < BTRFS_NR_RAID_TYPES; i++)
                 INIT_LIST_HEAD(&found->block_groups[i]);
         init_rwsem(&found->groups_sem);
@@ -3612,10 +3620,11 @@ alloc:
                 }
 
                 /*
-                 * If we have less pinned bytes than we want to allocate then
-                 * don't bother committing the transaction, it won't help us.
+                 * If we don't have enough pinned space to deal with this
+                 * allocation don't bother committing the transaction.
                  */
-                if (data_sinfo->bytes_pinned < bytes)
+                if (percpu_counter_compare(&data_sinfo->total_bytes_pinned,
+                                           bytes) < 0)
                         committed = 1;
                 spin_unlock(&data_sinfo->lock);
 
@@ -3624,6 +3633,7 @@ commit_trans:
                 if (!committed &&
                     !atomic_read(&root->fs_info->open_ioctl_trans)) {
                         committed = 1;
+
                         trans = btrfs_join_transaction(root);
                         if (IS_ERR(trans))
                                 return PTR_ERR(trans);
@@ -4044,7 +4054,8 @@ static int may_commit_transaction(struct btrfs_root *root,
 
         /* See if there is enough pinned space to make this reservation */
         spin_lock(&space_info->lock);
-        if (space_info->bytes_pinned >= bytes) {
+        if (percpu_counter_compare(&space_info->total_bytes_pinned,
+                                   bytes) >= 0) {
                 spin_unlock(&space_info->lock);
                 goto commit;
         }
@@ -4059,7 +4070,8 @@ static int may_commit_transaction(struct btrfs_root *root,
 
         spin_lock(&space_info->lock);
         spin_lock(&delayed_rsv->lock);
-        if (space_info->bytes_pinned + delayed_rsv->size < bytes) {
+        if (percpu_counter_compare(&space_info->total_bytes_pinned,
+                                   bytes - delayed_rsv->size) >= 0) {
                 spin_unlock(&delayed_rsv->lock);
                 spin_unlock(&space_info->lock);
                 return -ENOSPC;
@@ -5397,6 +5409,7 @@ void btrfs_prepare_extent_commit(struct btrfs_trans_handle *trans,
         struct btrfs_caching_control *next;
         struct btrfs_caching_control *caching_ctl;
         struct btrfs_block_group_cache *cache;
+        struct btrfs_space_info *space_info;
 
         down_write(&fs_info->extent_commit_sem);
 
@@ -5419,6 +5432,9 @@ void btrfs_prepare_extent_commit(struct btrfs_trans_handle *trans,
 
         up_write(&fs_info->extent_commit_sem);
 
+        list_for_each_entry_rcu(space_info, &fs_info->space_info, list)
+                percpu_counter_set(&space_info->total_bytes_pinned, 0);
+
         update_global_block_rsv(fs_info);
 }
 
@@ -5516,6 +5532,27 @@ int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
         return 0;
 }
 
+static void add_pinned_bytes(struct btrfs_fs_info *fs_info, u64 num_bytes,
+                             u64 owner, u64 root_objectid)
+{
+        struct btrfs_space_info *space_info;
+        u64 flags;
+
+        if (owner < BTRFS_FIRST_FREE_OBJECTID) {
+                if (root_objectid == BTRFS_CHUNK_TREE_OBJECTID)
+                        flags = BTRFS_BLOCK_GROUP_SYSTEM;
+                else
+                        flags = BTRFS_BLOCK_GROUP_METADATA;
+        } else {
+                flags = BTRFS_BLOCK_GROUP_DATA;
+        }
+
+        space_info = __find_space_info(fs_info, flags);
+        BUG_ON(!space_info); /* Logic bug */
+        percpu_counter_add(&space_info->total_bytes_pinned, num_bytes);
+}
+
+
 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
                                 struct btrfs_root *root,
                                 u64 bytenr, u64 num_bytes, u64 parent,
@@ -5736,6 +5773,8 @@ static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
                                 goto out;
                         }
                 }
+                add_pinned_bytes(root->fs_info, -num_bytes, owner_objectid,
+                                 root_objectid);
         } else {
                 if (found_extent) {
                         BUG_ON(is_data && refs_to_drop !=
@@ -5859,6 +5898,7 @@ void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
                            u64 parent, int last_ref)
 {
         struct btrfs_block_group_cache *cache = NULL;
+        int pin = 1;
         int ret;
 
         if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
@@ -5891,8 +5931,14 @@ void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
 
                 btrfs_add_free_space(cache, buf->start, buf->len);
                 btrfs_update_reserved_bytes(cache, buf->len, RESERVE_FREE);
+                pin = 0;
         }
 out:
+        if (pin)
+                add_pinned_bytes(root->fs_info, buf->len,
+                                 btrfs_header_level(buf),
+                                 root->root_key.objectid);
+
         /*
          * Deleting the buffer, clear the corrupt flag since it doesn't matter
          * anymore.
@@ -5909,6 +5955,8 @@ int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root *root,
         int ret;
         struct btrfs_fs_info *fs_info = root->fs_info;
 
+        add_pinned_bytes(root->fs_info, num_bytes, owner, root_objectid);
+
         /*
          * tree log blocks never actually go into the extent allocation
          * tree, just update pinning info and exit early.
@@ -8152,6 +8200,7 @@ int btrfs_free_block_groups(struct btrfs_fs_info *info)
                                 dump_space_info(space_info, 0, 0);
                         }
                 }
+                percpu_counter_destroy(&space_info->total_bytes_pinned);
                 list_del(&space_info->list);
                 kfree(space_info);
         }