reuse-path-object-in-ext4_move_extents

   1 ext4: reuse path object in ext4_move_extents()
   2
   3 Reuse the path object in ext4_move_extents() so we don't unnecessarily
   4 free and reallocate it.
   5
   6 Also clean up the get_ext_path() wrapper so that it has the same
   7 semantics of freeing the path object on error as ext4_ext_find_extent().
   8
   9 Signed-off-by: Theodore Ts'o <tytso@mit.edu>
  10 ---
  11  fs/ext4/move_extent.c | 27 ++++++++++++---------------
  12  1 file changed, 12 insertions(+), 15 deletions(-)
  13
  14 diff --git a/fs/ext4/move_extent.c b/fs/ext4/move_extent.c
  15 index a34c076..7bf970d 100644
  16 --- a/fs/ext4/move_extent.c
  17 +++ b/fs/ext4/move_extent.c
  18 @@ -32,20 +32,21 @@
  19   */
  20  static inline int
  21  get_ext_path(struct inode *inode, ext4_lblk_t lblock,
  22 -               struct ext4_ext_path **orig_path)
  23 +               struct ext4_ext_path **ppath)
  24  {
  25 -       int ret = 0;
  26         struct ext4_ext_path *path;
  27
  28 -       path = ext4_ext_find_extent(inode, lblock, orig_path, EXT4_EX_NOCACHE);
  29 +       path = ext4_ext_find_extent(inode, lblock, ppath, EXT4_EX_NOCACHE);
  30         if (IS_ERR(path))
  31 -               ret = PTR_ERR(path);
  32 -       else if (path[ext_depth(inode)].p_ext == NULL)
  33 -               ret = -ENODATA;
  34 -       else
  35 -               *orig_path = path;
  36 -
  37 -       return ret;
  38 +               return PTR_ERR(path);
  39 +       if (path[ext_depth(inode)].p_ext == NULL) {
  40 +               ext4_ext_drop_refs(path);
  41 +               kfree(path);
  42 +               *ppath = NULL;
  43 +               return -ENODATA;
  44 +       }
  45 +       *ppath = path;
  46 +       return 0;
  47  }
  48
  49  /**
  50 @@ -667,7 +668,7 @@ ext4_move_extents(struct file *o_filp, struct file *d_filp, __u64 orig_blk,
  51                         }
  52                         d_start += next_blk - o_start;
  53                         o_start = next_blk;
  54 -                       goto repeat;
  55 +                       continue;
  56                 /* Check hole after the start pos */
  57                 } else if (cur_blk > o_start) {
  58                         /* Skip hole */
  59 @@ -708,10 +709,6 @@ ext4_move_extents(struct file *o_filp, struct file *d_filp, __u64 orig_blk,
  60                         break;
  61                 o_start += cur_len;
  62                 d_start += cur_len;
  63 -       repeat:
  64 -               ext4_ext_drop_refs(path);
  65 -               kfree(path);
  66 -               path = NULL;
  67         }
  68         *moved_len = o_start - orig_blk;
  69         if (*moved_len > len)