ext4: store maxbytes for bitmapped files and return EFBIG as appropriate

Calculate & store the max offset for bitmapped files, and
catch too-large seeks, truncates, and writes in ext4, shortening
or rejecting as appropriate.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/include/linux/ext4_fs_sb.h b/include/linux/ext4_fs_sb.h
index f15821c5e4c4..38a47ec06df9 100644
--- a/include/linux/ext4_fs_sb.h
+++ b/include/linux/ext4_fs_sb.h
@@ -38,6 +38,7 @@ struct ext4_sb_info {
         ext4_group_t s_groups_count;    /* Number of groups in the fs */
         unsigned long s_overhead_last;  /* Last calculated overhead */
         unsigned long s_blocks_last;    /* Last seen block count */
+        loff_t s_bitmap_maxbytes;       /* max bytes for bitmap files */
         struct buffer_head * s_sbh;     /* Buffer containing the super block */
         struct ext4_super_block * s_es; /* Pointer to the super block in the buffer */
         struct buffer_head ** s_group_desc;