move-ext4_update_i_disksize-into-mpage_map_and_submit_extent

   1 ext4: move ext4_update_i_disksize() into mpage_map_and_submit_extent()
   2
   3 The function ext4_update_i_disksize() is used in only one place, in
   4 the function mpage_map_and_submit_extent().  Move there to simplify
   5 the code paths, and also move the call to ext4_mark_inode_dirty() into
   6 the i_data_sem's critical region, to be consistent with all of the
   7 other places where we update i_disksize.  That way, we also keep the
   8 raw_inode's i_disksize protected.
   9
  10 Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
  11 Cc: stable@vger.kernel.org
  12 ---
  13  fs/ext4/ext4.h  | 17 -----------------
  14  fs/ext4/inode.c | 16 +++++++++++++---
  15  2 files changed, 13 insertions(+), 20 deletions(-)
  16
  17 diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
  18 index f1c65dc..66946aa 100644
  19 --- a/fs/ext4/ext4.h
  20 +++ b/fs/ext4/ext4.h
  21 @@ -2466,23 +2466,6 @@ static inline void ext4_update_i_disksize(struct inode *inode, loff_t newsize)
  22         up_write(&EXT4_I(inode)->i_data_sem);
  23  }
  24
  25 -/*
  26 - * Update i_disksize after writeback has been started. Races with truncate
  27 - * are avoided by checking i_size under i_data_sem.
  28 - */
  29 -static inline void ext4_wb_update_i_disksize(struct inode *inode, loff_t newsize)
  30 -{
  31 -       loff_t i_size;
  32 -
  33 -       down_write(&EXT4_I(inode)->i_data_sem);
  34 -       i_size = i_size_read(inode);
  35 -       if (newsize > i_size)
  36 -               newsize = i_size;
  37 -       if (newsize > EXT4_I(inode)->i_disksize)
  38 -               EXT4_I(inode)->i_disksize = newsize;
  39 -       up_write(&EXT4_I(inode)->i_data_sem);
  40 -}
  41 -
  42  struct ext4_group_info {
  43         unsigned long   bb_state;
  44         struct rb_root  bb_free_root;
  45 diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
  46 index 7b93df9..f023f0c 100644
  47 --- a/fs/ext4/inode.c
  48 +++ b/fs/ext4/inode.c
  49 @@ -2247,13 +2247,23 @@ static int mpage_map_and_submit_extent(handle_t *handle,
  50                         return err;
  51         } while (map->m_len);
  52
  53 -       /* Update on-disk size after IO is submitted */
  54 +       /*
  55 +        * Update on-disk size after IO is submitted.  Races with
  56 +        * truncate are avoided by checking i_size under i_data_sem.
  57 +        */
  58         disksize = ((loff_t)mpd->first_page) << PAGE_CACHE_SHIFT;
  59         if (disksize > EXT4_I(inode)->i_disksize) {
  60                 int err2;
  61 -
  62 -               ext4_wb_update_i_disksize(inode, disksize);
  63 +               loff_t i_size;
  64 +
  65 +               down_write(&EXT4_I(inode)->i_data_sem);
  66 +               i_size = i_size_read(inode);
  67 +               if (disksize > i_size)
  68 +                       disksize = i_size;
  69 +               if (disksize > EXT4_I(inode)->i_disksize)
  70 +                       EXT4_I(inode)->i_disksize = disksize;
  71                 err2 = ext4_mark_inode_dirty(handle, inode);
  72 +               up_write(&EXT4_I(inode)->i_data_sem);
  73                 if (err2)
  74                         ext4_error(inode->i_sb,
  75                                    "Failed to mark inode %lu dirty",