ext4: move ext4_update_i_disksize() into mpage_map_and_submit_extent()

The function ext4_update_i_disksize() is used in only one place, in
the function mpage_map_and_submit_extent().  Move its code to simplify
the code paths, and also move the call to ext4_mark_inode_dirty() into
the i_data_sem's critical region, to be consistent with all of the
other places where we update i_disksize.  That way, we also keep the
raw_inode's i_disksize protected, to avoid the following race:

      CPU #1                                 CPU #2

   down_write(&i_data_sem)
   Modify i_disk_size
   up_write(&i_data_sem)
                                        down_write(&i_data_sem)
                                        Modify i_disk_size
                                        Copy i_disk_size to on-disk inode
                                        up_write(&i_data_sem)
   Copy i_disk_size to on-disk inode

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: stable@vger.kernel.org

1 files changed, 0 insertions, 17 deletions

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index f1c65dc7cc0a..66946aa62127 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -2466,23 +2466,6 @@ static inline void ext4_update_i_disksize(struct inode *inode, loff_t newsize)
         up_write(&EXT4_I(inode)->i_data_sem);
 }
 
-/*
- * Update i_disksize after writeback has been started. Races with truncate
- * are avoided by checking i_size under i_data_sem.
- */
-static inline void ext4_wb_update_i_disksize(struct inode *inode, loff_t newsize)
-{
-        loff_t i_size;
-
-        down_write(&EXT4_I(inode)->i_data_sem);
-        i_size = i_size_read(inode);
-        if (newsize > i_size)
-                newsize = i_size;
-        if (newsize > EXT4_I(inode)->i_disksize)
-                EXT4_I(inode)->i_disksize = newsize;
-        up_write(&EXT4_I(inode)->i_data_sem);
-}
-
 struct ext4_group_info {
         unsigned long   bb_state;
         struct rb_root  bb_free_root;