From 28739eea9cd42598b632972f5cc64a458c5d40b3 Mon Sep 17 00:00:00 2001
From: Lukas Czerner <lczerner@redhat.com>
Date: Tue, 24 May 2011 18:28:07 -0400
Subject: [PATCH] ext4: protect bb_first_free in ext4_trim_all_free() with
group lock
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>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
---
fs/ext4/mballoc.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 38a11bf793290..396b01f5c4fb7 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -4825,11 +4825,11 @@ ext4_trim_all_free(struct super_block *sb, ext4_group_t group,
"information for %u", group);
return ret;
}
-
bitmap = e4b.bd_bitmap;
+
+ ext4_lock_group(sb, group);
start = (e4b.bd_info->bb_first_free > start) ?
e4b.bd_info->bb_first_free : start;
- ext4_lock_group(sb, group);
while (start < max) {
start = mb_find_next_zero_bit(bitmap, max, start);
--
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