1 files changed, 32 insertions, 4 deletions

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 06e9a4152b14..5f805bc944fa 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -394,6 +394,14 @@ static noinline int compress_file_range(struct inode *inode,
             (start > 0 || end + 1 < BTRFS_I(inode)->disk_i_size))
                 btrfs_add_inode_defrag(NULL, inode);
 
+        /*
+         * skip compression for a small file range(<=blocksize) that
+         * isn't an inline extent, since it dosen't save disk space at all.
+         */
+        if ((end - start + 1) <= blocksize &&
+            (start > 0 || end + 1 < BTRFS_I(inode)->disk_i_size))
+                goto cleanup_and_bail_uncompressed;
+
         actual_end = min_t(u64, isize, end + 1);
 again:
         will_compress = 0;
@@ -1271,6 +1279,15 @@ next_slot:
                         disk_bytenr += cur_offset - found_key.offset;
                         num_bytes = min(end + 1, extent_end) - cur_offset;
                         /*
+                         * if there are pending snapshots for this root,
+                         * we fall into common COW way.
+                         */
+                        if (!nolock) {
+                                err = btrfs_start_nocow_write(root);
+                                if (!err)
+                                        goto out_check;
+                        }
+                        /*
                          * force cow if csum exists in the range.
                          * this ensure that csum for a given extent are
                          * either valid or do not exist.
@@ -1289,6 +1306,8 @@ next_slot:
 out_check:
                 if (extent_end <= start) {
                         path->slots[0]++;
+                        if (!nolock && nocow)
+                                btrfs_end_nocow_write(root);
                         goto next_slot;
                 }
                 if (!nocow) {
@@ -1306,8 +1325,11 @@ out_check:
                         ret = cow_file_range(inode, locked_page,
                                              cow_start, found_key.offset - 1,
                                              page_started, nr_written, 1);
-                        if (ret)
+                        if (ret) {
+                                if (!nolock && nocow)
+                                        btrfs_end_nocow_write(root);
                                 goto error;
+                        }
                         cow_start = (u64)-1;
                 }
 
@@ -1354,8 +1376,11 @@ out_check:
                     BTRFS_DATA_RELOC_TREE_OBJECTID) {
                         ret = btrfs_reloc_clone_csums(inode, cur_offset,
                                                       num_bytes);
-                        if (ret)
+                        if (ret) {
+                                if (!nolock && nocow)
+                                        btrfs_end_nocow_write(root);
                                 goto error;
+                        }
                 }
 
                 extent_clear_unlock_delalloc(inode, cur_offset,
@@ -1363,6 +1388,8 @@ out_check:
                                              locked_page, EXTENT_LOCKED |
                                              EXTENT_DELALLOC, PAGE_UNLOCK |
                                              PAGE_SET_PRIVATE2);
+                if (!nolock && nocow)
+                        btrfs_end_nocow_write(root);
                 cur_offset = extent_end;
                 if (cur_offset > end)
                         break;
@@ -8476,19 +8503,20 @@ static int __start_delalloc_inodes(struct btrfs_root *root, int delay_iput,
                         else
                                 iput(inode);
                         ret = -ENOMEM;
-                        break;
+                        goto out;
                 }
                 list_add_tail(&work->list, &works);
                 btrfs_queue_work(root->fs_info->flush_workers,
                                  &work->work);
                 ret++;
                 if (nr != -1 && ret >= nr)
-                        break;
+                        goto out;
                 cond_resched();
                 spin_lock(&root->delalloc_lock);
         }
         spin_unlock(&root->delalloc_lock);
 
+out:
         list_for_each_entry_safe(work, next, &works, list) {
                 list_del_init(&work->list);
                 btrfs_wait_and_free_delalloc_work(work);