ext4: add checksum calculation when clearing UNINIT flag in ext4_new_inode

When initializing an uninitialized block group in ext4_new_inode(),
its block group checksum must be re-calculated.  This fixes a race
when several threads try to allocate a new inode in an UNINIT'd group.

There is some question whether we need to be initializing the block
bitmap in ext4_new_inode() at all, but for now, if we are going to
init the block group, let's eliminate the race.

Signed-off-by: Frederic Bohe <frederic.bohe@bull.net>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

1 files changed, 2 insertions, 0 deletions

diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
index fe34d74cfb19..2a117e286e54 100644
--- a/fs/ext4/ialloc.c
+++ b/fs/ext4/ialloc.c
@@ -718,6 +718,8 @@ got:
                         gdp->bg_flags &= cpu_to_le16(~EXT4_BG_BLOCK_UNINIT);
                         free = ext4_free_blocks_after_init(sb, group, gdp);
                         gdp->bg_free_blocks_count = cpu_to_le16(free);
+                        gdp->bg_checksum = ext4_group_desc_csum(sbi, group,
+                                                                gdp);
                 }
                 spin_unlock(sb_bgl_lock(sbi, group));