1 files changed, 17 insertions, 10 deletions

diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 1933e8b07ed7..159a93450e26 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -1596,6 +1596,13 @@ again:
 
                 copied = btrfs_copy_from_user(pos, write_bytes, pages, i);
 
+                num_sectors = BTRFS_BYTES_TO_BLKS(root->fs_info,
+                                                reserve_bytes);
+                dirty_sectors = round_up(copied + sector_offset,
+                                        root->sectorsize);
+                dirty_sectors = BTRFS_BYTES_TO_BLKS(root->fs_info,
+                                                dirty_sectors);
+
                 /*
                  * if we have trouble faulting in the pages, fall
                  * back to one page at a time
@@ -1605,6 +1612,7 @@ again:
 
                 if (copied == 0) {
                         force_page_uptodate = true;
+                        dirty_sectors = 0;
                         dirty_pages = 0;
                 } else {
                         force_page_uptodate = false;
@@ -1615,20 +1623,19 @@ again:
                 /*
                  * If we had a short copy we need to release the excess delaloc
                  * bytes we reserved.  We need to increment outstanding_extents
-                 * because btrfs_delalloc_release_space will decrement it, but
+                 * because btrfs_delalloc_release_space and
+                 * btrfs_delalloc_release_metadata will decrement it, but
                  * we still have an outstanding extent for the chunk we actually
                  * managed to copy.
                  */
-                num_sectors = BTRFS_BYTES_TO_BLKS(root->fs_info,
-                                                reserve_bytes);
-                dirty_sectors = round_up(copied + sector_offset,
-                                        root->sectorsize);
-                dirty_sectors = BTRFS_BYTES_TO_BLKS(root->fs_info,
-                                                dirty_sectors);
-
                 if (num_sectors > dirty_sectors) {
-                        release_bytes = (write_bytes - copied)
-                                & ~((u64)root->sectorsize - 1);
+                        /*
+                         * we round down because we don't want to count
+                         * any partial blocks actually sent through the
+                         * IO machines
+                         */
+                        release_bytes = round_down(release_bytes - copied,
+                                      root->sectorsize);
                         if (copied > 0) {
                                 spin_lock(&BTRFS_I(inode)->lock);
                                 BTRFS_I(inode)->outstanding_extents++;