[PATCH] ext4: protect bb_first_free in ext4_trim_all_free() with group lock

[Lukas Czerner <lczerner@redhat.com>]

We should protect reading bd_info->bb_first_free with the group lock
because otherwise we might miss some free blocks. This is not a big deal
at all, but the change to do right thing is really simple, so lets do
that.

Signed-off-by: Lukas Czerner <lczerner@redhat.com>
---
 fs/ext4/mballoc.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 776d7a8..804232a 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -4775,11 +4775,11 @@ ext4_trim_all_free(struct super_block *sb, ext4_group_t group,
 				"information for %u", group);
 		return ret;
 	}