Btrfs: introduce per-subvolume delalloc inode list

When we create a snapshot, we need flush all delalloc inodes in the
fs, just flushing the inodes in the source tree is OK. So we introduce
per-subvolume delalloc inode list.

Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>

7 files changed, 183 insertions, 67 deletions

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 91a8ca7af77e..43c073533940 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1449,13 +1449,9 @@ struct btrfs_fs_info {
          */
         struct list_head ordered_extents;
 
-        spinlock_t delalloc_lock;
-        /*
-         * all of the inodes that have delalloc bytes.  It is possible for
-         * this list to be empty even when there is still dirty data=ordered
-         * extents waiting to finish IO.
-         */
-        struct list_head delalloc_inodes;
+        spinlock_t delalloc_root_lock;
+        /* all fs/file tree roots that have delalloc inodes. */
+        struct list_head delalloc_roots;
 
         /*
          * there is a pool of worker threads for checksumming during writes
@@ -1747,6 +1743,16 @@ struct btrfs_root {
 
         spinlock_t root_item_lock;
         atomic_t refs;
+
+        spinlock_t delalloc_lock;
+        /*
+         * all of the inodes that have delalloc bytes.  It is possible for
+         * this list to be empty even when there is still dirty data=ordered
+         * extents waiting to finish IO.
+         */
+        struct list_head delalloc_inodes;
+        struct list_head delalloc_root;
+        u64 nr_delalloc_inodes;
 };
 
 struct btrfs_ioctl_defrag_range_args {
@@ -3550,6 +3556,8 @@ int btrfs_truncate_inode_items(struct btrfs_trans_handle *trans,
                                u32 min_type);
 
 int btrfs_start_delalloc_inodes(struct btrfs_root *root, int delay_iput);
+int btrfs_start_all_delalloc_inodes(struct btrfs_fs_info *fs_info,
+                                    int delay_iput);
 int btrfs_set_extent_delalloc(struct inode *inode, u64 start, u64 end,
                               struct extent_state **cached_state);
 int btrfs_create_subvol_root(struct btrfs_trans_handle *trans,
diff --git a/fs/btrfs/dev-replace.c b/fs/btrfs/dev-replace.c
index 65241f32d3f8..2af312b6fb1f 100644
--- a/fs/btrfs/dev-replace.c
+++ b/fs/btrfs/dev-replace.c
@@ -470,7 +470,7 @@ static int btrfs_dev_replace_finishing(struct btrfs_fs_info *fs_info,
          * flush all outstanding I/O and inode extent mappings before the
          * copy operation is declared as being finished
          */
-        ret = btrfs_start_delalloc_inodes(root, 0);
+        ret = btrfs_start_all_delalloc_inodes(root->fs_info, 0);
         if (ret) {
                 mutex_unlock(&dev_replace->lock_finishing_cancel_unmount);
                 return ret;
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 90b643e07f3c..2748c7ccdd51 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1191,6 +1191,7 @@ static void __setup_root(u32 nodesize, u32 leafsize, u32 sectorsize,
         root->objectid = objectid;
         root->last_trans = 0;
         root->highest_objectid = 0;
+        root->nr_delalloc_inodes = 0;
         root->name = NULL;
         root->inode_tree = RB_ROOT;
         INIT_RADIX_TREE(&root->delayed_nodes_tree, GFP_ATOMIC);
@@ -1199,10 +1200,13 @@ static void __setup_root(u32 nodesize, u32 leafsize, u32 sectorsize,
 
         INIT_LIST_HEAD(&root->dirty_list);
         INIT_LIST_HEAD(&root->root_list);
+        INIT_LIST_HEAD(&root->delalloc_inodes);
+        INIT_LIST_HEAD(&root->delalloc_root);
         INIT_LIST_HEAD(&root->logged_list[0]);
         INIT_LIST_HEAD(&root->logged_list[1]);
         spin_lock_init(&root->orphan_lock);
         spin_lock_init(&root->inode_lock);
+        spin_lock_init(&root->delalloc_lock);
         spin_lock_init(&root->accounting_lock);
         spin_lock_init(&root->log_extents_lock[0]);
         spin_lock_init(&root->log_extents_lock[1]);
@@ -2140,9 +2144,9 @@ int open_ctree(struct super_block *sb,
         INIT_LIST_HEAD(&fs_info->trans_list);
         INIT_LIST_HEAD(&fs_info->dead_roots);
         INIT_LIST_HEAD(&fs_info->delayed_iputs);
-        INIT_LIST_HEAD(&fs_info->delalloc_inodes);
+        INIT_LIST_HEAD(&fs_info->delalloc_roots);
         INIT_LIST_HEAD(&fs_info->caching_block_groups);
-        spin_lock_init(&fs_info->delalloc_lock);
+        spin_lock_init(&fs_info->delalloc_root_lock);
         spin_lock_init(&fs_info->trans_lock);
         spin_lock_init(&fs_info->fs_roots_radix_lock);
         spin_lock_init(&fs_info->delayed_iput_lock);
@@ -3803,24 +3807,49 @@ static void btrfs_destroy_delalloc_inodes(struct btrfs_root *root)
 
         INIT_LIST_HEAD(&splice);
 
-        spin_lock(&root->fs_info->delalloc_lock);
-        list_splice_init(&root->fs_info->delalloc_inodes, &splice);
+        spin_lock(&root->delalloc_lock);
+        list_splice_init(&root->delalloc_inodes, &splice);
 
         while (!list_empty(&splice)) {
-                btrfs_inode = list_entry(splice.next, struct btrfs_inode,
-                                    delalloc_inodes);
+                btrfs_inode = list_first_entry(&splice, struct btrfs_inode,
+                                               delalloc_inodes);
 
                 list_del_init(&btrfs_inode->delalloc_inodes);
                 clear_bit(BTRFS_INODE_IN_DELALLOC_LIST,
                           &btrfs_inode->runtime_flags);
-                spin_unlock(&root->fs_info->delalloc_lock);
+                spin_unlock(&root->delalloc_lock);
 
                 btrfs_invalidate_inodes(btrfs_inode->root);
 
-                spin_lock(&root->fs_info->delalloc_lock);
+                spin_lock(&root->delalloc_lock);
         }
 
-        spin_unlock(&root->fs_info->delalloc_lock);
+        spin_unlock(&root->delalloc_lock);
+}
+
+static void btrfs_destroy_all_delalloc_inodes(struct btrfs_fs_info *fs_info)
+{
+        struct btrfs_root *root;
+        struct list_head splice;
+
+        INIT_LIST_HEAD(&splice);
+
+        spin_lock(&fs_info->delalloc_root_lock);
+        list_splice_init(&fs_info->delalloc_roots, &splice);
+        while (!list_empty(&splice)) {
+                root = list_first_entry(&splice, struct btrfs_root,
+                                         delalloc_root);
+                list_del_init(&root->delalloc_root);
+                root = btrfs_grab_fs_root(root);
+                BUG_ON(!root);
+                spin_unlock(&fs_info->delalloc_root_lock);
+
+                btrfs_destroy_delalloc_inodes(root);
+                btrfs_put_fs_root(root);
+
+                spin_lock(&fs_info->delalloc_root_lock);
+        }
+        spin_unlock(&fs_info->delalloc_root_lock);
 }
 
 static int btrfs_destroy_marked_extents(struct btrfs_root *root,
@@ -3974,7 +4003,7 @@ static int btrfs_cleanup_transaction(struct btrfs_root *root)
                 btrfs_destroy_delayed_inodes(root);
                 btrfs_assert_delayed_root_empty(root);
 
-                btrfs_destroy_delalloc_inodes(root);
+                btrfs_destroy_all_delalloc_inodes(root->fs_info);
 
                 spin_lock(&root->fs_info->trans_lock);
                 root->fs_info->running_transaction = NULL;
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 04066c2cc711..f8ff06834e79 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -3899,7 +3899,7 @@ static void btrfs_writeback_inodes_sb_nr(struct btrfs_root *root,
                  * the filesystem is readonly(all dirty pages are written to
                  * the disk).
                  */
-                btrfs_start_delalloc_inodes(root, 0);
+                btrfs_start_all_delalloc_inodes(root->fs_info, 0);
                 if (!current->journal_info)
                         btrfs_wait_ordered_extents(root, 0);
         }
@@ -5030,14 +5030,14 @@ static int update_block_group(struct btrfs_root *root,
         int factor;
 
         /* block accounting for super block */
-        spin_lock(&info->delalloc_lock);
+        spin_lock(&info->delalloc_root_lock);
         old_val = btrfs_super_bytes_used(info->super_copy);
         if (alloc)
                 old_val += num_bytes;
         else
                 old_val -= num_bytes;
         btrfs_set_super_bytes_used(info->super_copy, old_val);
-        spin_unlock(&info->delalloc_lock);
+        spin_unlock(&info->delalloc_root_lock);
 
         while (total) {
                 cache = btrfs_lookup_block_group(info, bytenr);
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 3817c1e49035..18191f193b47 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -1528,6 +1528,46 @@ static void btrfs_merge_extent_hook(struct inode *inode,
         spin_unlock(&BTRFS_I(inode)->lock);
 }
 
+static void btrfs_add_delalloc_inodes(struct btrfs_root *root,
+                                      struct inode *inode)
+{
+        spin_lock(&root->delalloc_lock);
+        if (list_empty(&BTRFS_I(inode)->delalloc_inodes)) {
+                list_add_tail(&BTRFS_I(inode)->delalloc_inodes,
+                              &root->delalloc_inodes);
+                set_bit(BTRFS_INODE_IN_DELALLOC_LIST,
+                        &BTRFS_I(inode)->runtime_flags);
+                root->nr_delalloc_inodes++;
+                if (root->nr_delalloc_inodes == 1) {
+                        spin_lock(&root->fs_info->delalloc_root_lock);
+                        BUG_ON(!list_empty(&root->delalloc_root));
+                        list_add_tail(&root->delalloc_root,
+                                      &root->fs_info->delalloc_roots);
+                        spin_unlock(&root->fs_info->delalloc_root_lock);
+                }
+        }
+        spin_unlock(&root->delalloc_lock);
+}
+
+static void btrfs_del_delalloc_inode(struct btrfs_root *root,
+                                     struct inode *inode)
+{
+        spin_lock(&root->delalloc_lock);
+        if (!list_empty(&BTRFS_I(inode)->delalloc_inodes)) {
+                list_del_init(&BTRFS_I(inode)->delalloc_inodes);
+                clear_bit(BTRFS_INODE_IN_DELALLOC_LIST,
+                          &BTRFS_I(inode)->runtime_flags);
+                root->nr_delalloc_inodes--;
+                if (!root->nr_delalloc_inodes) {
+                        spin_lock(&root->fs_info->delalloc_root_lock);
+                        BUG_ON(list_empty(&root->delalloc_root));
+                        list_del_init(&root->delalloc_root);
+                        spin_unlock(&root->fs_info->delalloc_root_lock);
+                }
+        }
+        spin_unlock(&root->delalloc_lock);
+}
+
 /*
  * extent_io.c set_bit_hook, used to track delayed allocation
  * bytes in this file, and to maintain the list of inodes that
@@ -1560,16 +1600,8 @@ static void btrfs_set_bit_hook(struct inode *inode,
                 spin_lock(&BTRFS_I(inode)->lock);
                 BTRFS_I(inode)->delalloc_bytes += len;
                 if (do_list && !test_bit(BTRFS_INODE_IN_DELALLOC_LIST,
-                                         &BTRFS_I(inode)->runtime_flags)) {
-                        spin_lock(&root->fs_info->delalloc_lock);
-                        if (list_empty(&BTRFS_I(inode)->delalloc_inodes)) {
-                                list_add_tail(&BTRFS_I(inode)->delalloc_inodes,
-                                              &root->fs_info->delalloc_inodes);
-                                set_bit(BTRFS_INODE_IN_DELALLOC_LIST,
-                                        &BTRFS_I(inode)->runtime_flags);
-                        }
-                        spin_unlock(&root->fs_info->delalloc_lock);
-                }
+                                         &BTRFS_I(inode)->runtime_flags))
+                        btrfs_add_delalloc_inodes(root, inode);
                 spin_unlock(&BTRFS_I(inode)->lock);
         }
 }
@@ -1612,15 +1644,8 @@ static void btrfs_clear_bit_hook(struct inode *inode,
                 BTRFS_I(inode)->delalloc_bytes -= len;
                 if (do_list && BTRFS_I(inode)->delalloc_bytes == 0 &&
                     test_bit(BTRFS_INODE_IN_DELALLOC_LIST,
-                             &BTRFS_I(inode)->runtime_flags)) {
-                        spin_lock(&root->fs_info->delalloc_lock);
-                        if (!list_empty(&BTRFS_I(inode)->delalloc_inodes)) {
-                                list_del_init(&BTRFS_I(inode)->delalloc_inodes);
-                                clear_bit(BTRFS_INODE_IN_DELALLOC_LIST,
-                                          &BTRFS_I(inode)->runtime_flags);
-                        }
-                        spin_unlock(&root->fs_info->delalloc_lock);
-                }
+                             &BTRFS_I(inode)->runtime_flags))
+                        btrfs_del_delalloc_inode(root, inode);
                 spin_unlock(&BTRFS_I(inode)->lock);
         }
 }
@@ -8338,7 +8363,7 @@ void btrfs_wait_and_free_delalloc_work(struct btrfs_delalloc_work *work)
  * some fairly slow code that needs optimization. This walks the list
  * of all the inodes with pending delalloc and forces them to disk.
  */
-int btrfs_start_delalloc_inodes(struct btrfs_root *root, int delay_iput)
+static int __start_delalloc_inodes(struct btrfs_root *root, int delay_iput)
 {
         struct btrfs_inode *binode;
         struct inode *inode;
@@ -8347,30 +8372,23 @@ int btrfs_start_delalloc_inodes(struct btrfs_root *root, int delay_iput)
         struct list_head splice;
         int ret = 0;
 
-        if (root->fs_info->sb->s_flags & MS_RDONLY)
-                return -EROFS;
-
         INIT_LIST_HEAD(&works);
         INIT_LIST_HEAD(&splice);
 
-        spin_lock(&root->fs_info->delalloc_lock);
-        list_splice_init(&root->fs_info->delalloc_inodes, &splice);
+        spin_lock(&root->delalloc_lock);
+        list_splice_init(&root->delalloc_inodes, &splice);
         while (!list_empty(&splice)) {
                 binode = list_entry(splice.next, struct btrfs_inode,
                                     delalloc_inodes);
 
-                list_del_init(&binode->delalloc_inodes);
-
+                list_move_tail(&binode->delalloc_inodes,
+                               &root->delalloc_inodes);
                 inode = igrab(&binode->vfs_inode);
                 if (!inode) {
-                        clear_bit(BTRFS_INODE_IN_DELALLOC_LIST,
-                                  &binode->runtime_flags);
+                        cond_resched_lock(&root->delalloc_lock);
                         continue;
                 }
-
-                list_add_tail(&binode->delalloc_inodes,
-                              &root->fs_info->delalloc_inodes);
-                spin_unlock(&root->fs_info->delalloc_lock);
+                spin_unlock(&root->delalloc_lock);
 
                 work = btrfs_alloc_delalloc_work(inode, 0, delay_iput);
                 if (unlikely(!work)) {
@@ -8382,16 +8400,39 @@ int btrfs_start_delalloc_inodes(struct btrfs_root *root, int delay_iput)
                                    &work->work);
 
                 cond_resched();
-                spin_lock(&root->fs_info->delalloc_lock);
+                spin_lock(&root->delalloc_lock);
         }
-        spin_unlock(&root->fs_info->delalloc_lock);
+        spin_unlock(&root->delalloc_lock);
 
         list_for_each_entry_safe(work, next, &works, list) {
                 list_del_init(&work->list);
                 btrfs_wait_and_free_delalloc_work(work);
         }
+        return 0;
+out:
+        list_for_each_entry_safe(work, next, &works, list) {
+                list_del_init(&work->list);
+                btrfs_wait_and_free_delalloc_work(work);
+        }
+
+        if (!list_empty_careful(&splice)) {
+                spin_lock(&root->delalloc_lock);
+                list_splice_tail(&splice, &root->delalloc_inodes);
+                spin_unlock(&root->delalloc_lock);
+        }
+        return ret;
+}
 
-        /* the filemap_flush will queue IO into the worker threads, but
+int btrfs_start_delalloc_inodes(struct btrfs_root *root, int delay_iput)
+{
+        int ret;
+
+        if (root->fs_info->sb->s_flags & MS_RDONLY)
+                return -EROFS;
+
+        ret = __start_delalloc_inodes(root, delay_iput);
+        /*
+         * the filemap_flush will queue IO into the worker threads, but
          * we have to make sure the IO is actually started and that
          * ordered extents get created before we return
          */
@@ -8403,17 +8444,55 @@ int btrfs_start_delalloc_inodes(struct btrfs_root *root, int delay_iput)
                     atomic_read(&root->fs_info->async_delalloc_pages) == 0));
         }
         atomic_dec(&root->fs_info->async_submit_draining);
-        return 0;
-out:
-        list_for_each_entry_safe(work, next, &works, list) {
-                list_del_init(&work->list);
-                btrfs_wait_and_free_delalloc_work(work);
+        return ret;
+}
+
+int btrfs_start_all_delalloc_inodes(struct btrfs_fs_info *fs_info,
+                                    int delay_iput)
+{
+        struct btrfs_root *root;
+        struct list_head splice;
+        int ret;
+
+        if (fs_info->sb->s_flags & MS_RDONLY)
+                return -EROFS;
+
+        INIT_LIST_HEAD(&splice);
+
+        spin_lock(&fs_info->delalloc_root_lock);
+        list_splice_init(&fs_info->delalloc_roots, &splice);
+        while (!list_empty(&splice)) {
+                root = list_first_entry(&splice, struct btrfs_root,
+                                        delalloc_root);
+                root = btrfs_grab_fs_root(root);
+                BUG_ON(!root);
+                list_move_tail(&root->delalloc_root,
+                               &fs_info->delalloc_roots);
+                spin_unlock(&fs_info->delalloc_root_lock);
+
+                ret = __start_delalloc_inodes(root, delay_iput);
+                btrfs_put_fs_root(root);
+                if (ret)
+                        goto out;
+
+                spin_lock(&fs_info->delalloc_root_lock);
         }
+        spin_unlock(&fs_info->delalloc_root_lock);
 
+        atomic_inc(&fs_info->async_submit_draining);
+        while (atomic_read(&fs_info->nr_async_submits) ||
+              atomic_read(&fs_info->async_delalloc_pages)) {
+                wait_event(fs_info->async_submit_wait,
+                   (atomic_read(&fs_info->nr_async_submits) == 0 &&
+                    atomic_read(&fs_info->async_delalloc_pages) == 0));
+        }
+        atomic_dec(&fs_info->async_submit_draining);
+        return 0;
+out:
         if (!list_empty_careful(&splice)) {
-                spin_lock(&root->fs_info->delalloc_lock);
-                list_splice_tail(&splice, &root->fs_info->delalloc_inodes);
-                spin_unlock(&root->fs_info->delalloc_lock);
+                spin_lock(&fs_info->delalloc_root_lock);
+                list_splice_tail(&splice, &fs_info->delalloc_roots);
+                spin_unlock(&fs_info->delalloc_root_lock);
         }
         return ret;
 }
diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index f46b4cca4fa2..f6e1b54f05d8 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -4159,7 +4159,7 @@ int btrfs_relocate_block_group(struct btrfs_root *extent_root, u64 group_start)
                (unsigned long long)rc->block_group->key.objectid,
                (unsigned long long)rc->block_group->flags);
 
-        ret = btrfs_start_delalloc_inodes(fs_info->tree_root, 0);
+        ret = btrfs_start_all_delalloc_inodes(fs_info, 0);
         if (ret < 0) {
                 err = ret;
                 goto out;
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index f157752efc47..4b6311181412 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -1502,7 +1502,7 @@ static int btrfs_flush_all_pending_stuffs(struct btrfs_trans_handle *trans,
         }
 
         if (flush_on_commit || snap_pending) {
-                ret = btrfs_start_delalloc_inodes(root, 1);
+                ret = btrfs_start_all_delalloc_inodes(root->fs_info, 1);
                 if (ret)
                         return ret;
                 btrfs_wait_ordered_extents(root, 1);