Btrfs: don't flush all delalloc inodes when we doesn't get s_umount lock

We needn't flush all delalloc inodes when we doesn't get s_umount lock,
or we would make the tasks wait for a long time.

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

1 files changed, 19 insertions, 15 deletions

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index f5e623371bf3..fbaf1ac3941b 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -8437,7 +8437,8 @@ 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.
  */
-static int __start_delalloc_inodes(struct btrfs_root *root, int delay_iput)
+static int __start_delalloc_inodes(struct btrfs_root *root, int delay_iput,
+                                   int nr)
 {
         struct btrfs_inode *binode;
         struct inode *inode;
@@ -8471,12 +8472,14 @@ static int __start_delalloc_inodes(struct btrfs_root *root, int delay_iput)
                         else
                                 iput(inode);
                         ret = -ENOMEM;
-                        goto out;
+                        break;
                 }
                 list_add_tail(&work->list, &works);
                 btrfs_queue_work(root->fs_info->flush_workers,
                                  &work->work);
-
+                ret++;
+                if (nr != -1 && ret >= nr)
+                        break;
                 cond_resched();
                 spin_lock(&root->delalloc_lock);
         }
@@ -8486,12 +8489,6 @@ static int __start_delalloc_inodes(struct btrfs_root *root, int delay_iput)
                 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);
@@ -8508,7 +8505,9 @@ int btrfs_start_delalloc_inodes(struct btrfs_root *root, int delay_iput)
         if (test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state))
                 return -EROFS;
 
-        ret = __start_delalloc_inodes(root, delay_iput);
+        ret = __start_delalloc_inodes(root, delay_iput, -1);
+        if (ret > 0)
+                ret = 0;
         /*
          * the filemap_flush will queue IO into the worker threads, but
          * we have to make sure the IO is actually started and that
@@ -8525,7 +8524,8 @@ int btrfs_start_delalloc_inodes(struct btrfs_root *root, int delay_iput)
         return ret;
 }
 
-int btrfs_start_delalloc_roots(struct btrfs_fs_info *fs_info, int delay_iput)
+int btrfs_start_delalloc_roots(struct btrfs_fs_info *fs_info, int delay_iput,
+                               int nr)
 {
         struct btrfs_root *root;
         struct list_head splice;
@@ -8538,7 +8538,7 @@ int btrfs_start_delalloc_roots(struct btrfs_fs_info *fs_info, int delay_iput)
 
         spin_lock(&fs_info->delalloc_root_lock);
         list_splice_init(&fs_info->delalloc_roots, &splice);
-        while (!list_empty(&splice)) {
+        while (!list_empty(&splice) && nr) {
                 root = list_first_entry(&splice, struct btrfs_root,
                                         delalloc_root);
                 root = btrfs_grab_fs_root(root);
@@ -8547,15 +8547,20 @@ int btrfs_start_delalloc_roots(struct btrfs_fs_info *fs_info, int delay_iput)
                                &fs_info->delalloc_roots);
                 spin_unlock(&fs_info->delalloc_root_lock);
 
-                ret = __start_delalloc_inodes(root, delay_iput);
+                ret = __start_delalloc_inodes(root, delay_iput, nr);
                 btrfs_put_fs_root(root);
-                if (ret)
+                if (ret < 0)
                         goto out;
 
+                if (nr != -1) {
+                        nr -= ret;
+                        WARN_ON(nr < 0);
+                }
                 spin_lock(&fs_info->delalloc_root_lock);
         }
         spin_unlock(&fs_info->delalloc_root_lock);
 
+        ret = 0;
         atomic_inc(&fs_info->async_submit_draining);
         while (atomic_read(&fs_info->nr_async_submits) ||
               atomic_read(&fs_info->async_delalloc_pages)) {
@@ -8564,7 +8569,6 @@ int btrfs_start_delalloc_roots(struct btrfs_fs_info *fs_info, int delay_iput)
                     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(&fs_info->delalloc_root_lock);