avoid-calling-ext4_mark_inode_dirty-under-unneeded-locks

   1 ext4: avoid calling ext4_mark_inode_dirty() under unneeded semaphores
   2
   3 There is no need to call ext4_mark_inode_dirty while holding xattr_sem
   4 or i_data_sem, so where it's easy to avoid it, move it out from the
   5 critical region.
   6
   7 Signed-off-by: Theodore Ts'o <tytso@mit.edu>
   8 ---
   9  fs/ext4/inline.c | 9 +++------
  10  fs/ext4/inode.c  | 2 +-
  11  2 files changed, 4 insertions(+), 7 deletions(-)
  12
  13 diff --git a/fs/ext4/inline.c b/fs/ext4/inline.c
  14 index 99a5312ced52..31f98dd04e51 100644
  15 --- a/fs/ext4/inline.c
  16 +++ b/fs/ext4/inline.c
  17 @@ -1042,7 +1042,6 @@ static int ext4_add_dirent_to_inline(handle_t *handle,
  18         dir->i_mtime = dir->i_ctime = current_time(dir);
  19         ext4_update_dx_flag(dir);
  20         dir->i_version++;
  21 -       ext4_mark_inode_dirty(handle, dir);
  22         return 1;
  23  }
  24
  25 @@ -1311,8 +1310,8 @@ int ext4_try_add_inline_entry(handle_t *handle, struct ext4_filename *fname,
  26         ret = ext4_convert_inline_data_nolock(handle, dir, &iloc);
  27
  28  out:
  29 -       ext4_mark_inode_dirty(handle, dir);
  30         ext4_write_unlock_xattr(dir, &no_expand);
  31 +       ext4_mark_inode_dirty(handle, dir);
  32         brelse(iloc.bh);
  33         return ret;
  34  }
  35 @@ -1708,13 +1707,11 @@ int ext4_delete_inline_entry(handle_t *handle,
  36         if (err)
  37                 goto out;
  38
  39 -       err = ext4_mark_inode_dirty(handle, dir);
  40 -       if (unlikely(err))
  41 -               goto out;
  42 -
  43         ext4_show_inline_dir(dir, iloc.bh, inline_start, inline_size);
  44  out:
  45         ext4_write_unlock_xattr(dir, &no_expand);
  46 +       if (likely(err == 0))
  47 +               err = ext4_mark_inode_dirty(handle, dir);
  48         brelse(iloc.bh);
  49         if (err != -ENOENT)
  50                 ext4_std_error(dir->i_sb, err);
  51 diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
  52 index 88d57af1b516..86dde0667ccc 100644
  53 --- a/fs/ext4/inode.c
  54 +++ b/fs/ext4/inode.c
  55 @@ -2464,8 +2464,8 @@ static int mpage_map_and_submit_extent(handle_t *handle,
  56                         disksize = i_size;
  57                 if (disksize > EXT4_I(inode)->i_disksize)
  58                         EXT4_I(inode)->i_disksize = disksize;
  59 -               err2 = ext4_mark_inode_dirty(handle, inode);
  60                 up_write(&EXT4_I(inode)->i_data_sem);
  61 +               err2 = ext4_mark_inode_dirty(handle, inode);
  62                 if (err2)
  63                         ext4_error(inode->i_sb,
  64                                    "Failed to mark inode %lu dirty",