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Diffstat (limited to 'fs/ext4/balloc.c')
-rw-r--r--fs/ext4/balloc.c14
1 files changed, 11 insertions, 3 deletions
diff --git a/fs/ext4/balloc.c b/fs/ext4/balloc.c
index 5f993a411251..8fd0b3cdab4c 100644
--- a/fs/ext4/balloc.c
+++ b/fs/ext4/balloc.c
@@ -270,6 +270,7 @@ struct ext4_group_desc * ext4_get_group_desc(struct super_block *sb,
ext4_group_t ngroups = ext4_get_groups_count(sb);
struct ext4_group_desc *desc;
struct ext4_sb_info *sbi = EXT4_SB(sb);
+ struct buffer_head *bh_p;
if (block_group >= ngroups) {
ext4_error(sb, "block_group >= groups_count - block_group = %u,"
@@ -280,7 +281,14 @@ struct ext4_group_desc * ext4_get_group_desc(struct super_block *sb,
group_desc = block_group >> EXT4_DESC_PER_BLOCK_BITS(sb);
offset = block_group & (EXT4_DESC_PER_BLOCK(sb) - 1);
- if (!sbi->s_group_desc[group_desc]) {
+ bh_p = sbi_array_rcu_deref(sbi, s_group_desc, group_desc);
+ /*
+ * sbi_array_rcu_deref returns with rcu unlocked, this is ok since
+ * the pointer being dereferenced won't be dereferenced again. By
+ * looking at the usage in add_new_gdb() the value isn't modified,
+ * just the pointer, and so it remains valid.
+ */
+ if (!bh_p) {
ext4_error(sb, "Group descriptor not loaded - "
"block_group = %u, group_desc = %u, desc = %u",
block_group, group_desc, offset);
@@ -288,10 +296,10 @@ struct ext4_group_desc * ext4_get_group_desc(struct super_block *sb,
}
desc = (struct ext4_group_desc *)(
- (__u8 *)sbi->s_group_desc[group_desc]->b_data +
+ (__u8 *)bh_p->b_data +
offset * EXT4_DESC_SIZE(sb));
if (bh)
- *bh = sbi->s_group_desc[group_desc];
+ *bh = bh_p;
return desc;
}