Btrfs: don't lock bits in the extent tree during writepage

At writepage time, we have the page locked and we have the
extent_map entry for this extent pinned in the extent_map tree.
So, the page can't go away and its mapping can't change.

There is no need for the extra extent_state lock bits during writepage.

Signed-off-by: Chris Mason <chris.mason@oracle.com>

1 files changed, 0 insertions, 21 deletions

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index c7a5e860fe2..04fafc3cffc 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -2219,16 +2219,10 @@ static int __extent_writepage(struct page *page, struct writeback_control *wbc,
                         goto done_unlocked;
                 }
         }
-        lock_extent_bits(tree, start, page_end, 0, &cached_state, GFP_NOFS);
-
-        unlock_start = start;
-
         if (tree->ops && tree->ops->writepage_start_hook) {
                 ret = tree->ops->writepage_start_hook(page, start,
                                                       page_end);
                 if (ret == -EAGAIN) {
-                        unlock_extent_cached(tree, start, page_end,
-                                             &cached_state, GFP_NOFS);
                         redirty_page_for_writepage(wbc, page);
                         update_nr_written(page, wbc, nr_written);
                         unlock_page(page);
@@ -2244,13 +2238,7 @@ static int __extent_writepage(struct page *page, struct writeback_control *wbc,
         update_nr_written(page, wbc, nr_written + 1);
 
         end = page_end;
-        if (test_range_bit(tree, start, page_end, EXTENT_DELALLOC, 0))
-                printk(KERN_ERR "btrfs delalloc bits after lock_extent\n");
-
         if (last_byte <= start) {
-                clear_extent_bit(tree, start, page_end,
-                                 EXTENT_LOCKED | EXTENT_DIRTY,
-                                 1, 0, NULL, GFP_NOFS);
                 if (tree->ops && tree->ops->writepage_end_io_hook)
                         tree->ops->writepage_end_io_hook(page, start,
                                                          page_end, NULL, 1);
@@ -2262,8 +2250,6 @@ static int __extent_writepage(struct page *page, struct writeback_control *wbc,
 
         while (cur <= end) {
                 if (cur >= last_byte) {
-                        unlock_extent_cached(tree, unlock_start, page_end,
-                                             &cached_state, GFP_NOFS);
                         if (tree->ops && tree->ops->writepage_end_io_hook)
                                 tree->ops->writepage_end_io_hook(page, cur,
                                                          page_end, NULL, 1);
@@ -2295,10 +2281,6 @@ static int __extent_writepage(struct page *page, struct writeback_control *wbc,
                  */
                 if (compressed || block_start == EXTENT_MAP_HOLE ||
                     block_start == EXTENT_MAP_INLINE) {
-                        unlock_extent_cached(tree, unlock_start,
-                                             cur + iosize - 1, &cached_state,
-                                             GFP_NOFS);
-
                         /*
                          * end_io notification does not happen here for
                          * compressed extents
@@ -2366,9 +2348,6 @@ done:
                 set_page_writeback(page);
                 end_page_writeback(page);
         }
-        if (unlock_start <= page_end)
-                unlock_extent_cached(tree, unlock_start, page_end,
-                                     &cached_state, GFP_NOFS);
         unlock_page(page);
 
 done_unlocked: