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>

7 files changed, 29 insertions, 24 deletions

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 374bb2f8ccd9..5a800986f416 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -3740,7 +3740,8 @@ 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_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);
 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 ec1c3f3a775d..9f2290509aca 100644
--- a/fs/btrfs/dev-replace.c
+++ b/fs/btrfs/dev-replace.c
@@ -491,7 +491,7 @@ 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_roots(root->fs_info, 0);
+        ret = btrfs_start_delalloc_roots(root->fs_info, 0, -1);
         if (ret) {
                 mutex_unlock(&dev_replace->lock_finishing_cancel_unmount);
                 return ret;
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 5c0c5457268a..c6b6a6e3e735 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -3971,7 +3971,7 @@ static int can_overcommit(struct btrfs_root *root,
 }
 
 static void btrfs_writeback_inodes_sb_nr(struct btrfs_root *root,
-                                         unsigned long nr_pages)
+                                         unsigned long nr_pages, int nr_items)
 {
         struct super_block *sb = root->fs_info->sb;
 
@@ -3986,9 +3986,9 @@ 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_roots(root->fs_info, 0);
+                btrfs_start_delalloc_roots(root->fs_info, 0, nr_items);
                 if (!current->journal_info)
-                        btrfs_wait_ordered_roots(root->fs_info, -1);
+                        btrfs_wait_ordered_roots(root->fs_info, nr_items);
         }
 }
 
@@ -4045,7 +4045,7 @@ static void shrink_delalloc(struct btrfs_root *root, u64 to_reclaim, u64 orig,
         while (delalloc_bytes && loops < 3) {
                 max_reclaim = min(delalloc_bytes, to_reclaim);
                 nr_pages = max_reclaim >> PAGE_CACHE_SHIFT;
-                btrfs_writeback_inodes_sb_nr(root, nr_pages);
+                btrfs_writeback_inodes_sb_nr(root, nr_pages, items);
                 /*
                  * We need to wait for the async pages to actually start before
                  * we do anything.
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);
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 57bc9f33fa3c..e1747701f520 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -4893,7 +4893,7 @@ long btrfs_ioctl(struct file *file, unsigned int
         case BTRFS_IOC_SYNC: {
                 int ret;
 
-                ret = btrfs_start_delalloc_roots(root->fs_info, 0);
+                ret = btrfs_start_delalloc_roots(root->fs_info, 0, -1);
                 if (ret)
                         return ret;
                 ret = btrfs_sync_fs(file->f_dentry->d_sb, 1);
diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index 07b3b36f40ee..def428a25b2a 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -4248,7 +4248,7 @@ int btrfs_relocate_block_group(struct btrfs_root *extent_root, u64 group_start)
         btrfs_info(extent_root->fs_info, "relocating block group %llu flags %llu",
                rc->block_group->key.objectid, rc->block_group->flags);
 
-        ret = btrfs_start_delalloc_roots(fs_info, 0);
+        ret = btrfs_start_delalloc_roots(fs_info, 0, -1);
         if (ret < 0) {
                 err = ret;
                 goto out;
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index 79a4186b724a..a999b85d1176 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -1620,7 +1620,7 @@ static int btrfs_flush_all_pending_stuffs(struct btrfs_trans_handle *trans,
 static inline int btrfs_start_delalloc_flush(struct btrfs_fs_info *fs_info)
 {
         if (btrfs_test_opt(fs_info->tree_root, FLUSHONCOMMIT))
-                return btrfs_start_delalloc_roots(fs_info, 1);
+                return btrfs_start_delalloc_roots(fs_info, 1, -1);
         return 0;
 }