Revert "Btrfs: adjust len of writes if following a preallocated extent"

This is exposing an existing deadlock between fsync and AIO.  Until we
have the deadlock fixed, I'm pulling this one out.

This reverts commit a23eaa875f0f1d89eb866b8c9860e78273ff5daf.

Signed-off-by: Chris Mason <clm@fb.com>

1 files changed, 3 insertions, 5 deletions

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index dbcec1ced85a..a713d9d324b0 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -7765,12 +7765,10 @@ static int btrfs_get_blocks_direct(struct inode *inode, sector_t iblock,
         }
 
         /*
-         * this will cow the extent, if em is within [start, len], then
-         * probably we've found a preallocated/existing extent, let's
-         * give it a chance to use preallocated space.
+         * this will cow the extent, reset the len in case we changed
+         * it above
          */
-        len = min_t(u64, bh_result->b_size, em->len - (start - em->start));
-        len = ALIGN(len, fs_info->sectorsize);
+        len = bh_result->b_size;
         free_extent_map(em);
         em = btrfs_new_extent_direct(inode, start, len);
         if (IS_ERR(em)) {