>From 020243735e97f327ecba729ec05d4e3facdddc78 Mon Sep 17 00:00:00 2001
From: Niu Yawei <niu@xxxxxxxxxxxxx>
Date: Mon, 7 Jan 2013 01:03:26 -0500
Subject: [PATCH] Fix race in ext4_mb_add_n_trim()
In ext4_mb_add_n_trim(), lg_prealloc_lock should be taken when
changing the lg_prealloc_list.
Signed-off-by: Niu Yawei <yawei.niu@xxxxxxxxx>
---
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 1bf6fe7..45d3527 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -4136,7 +4136,7 @@ static void ext4_mb_add_n_trim(struct ext4_allocation_context *ac)
/* The max size of hash table is PREALLOC_TB_SIZE */
order = PREALLOC_TB_SIZE - 1;
/* Add the prealloc space to lg */
- rcu_read_lock();
+ spin_lock(&lg->lg_prealloc_lock);
list_for_each_entry_rcu(tmp_pa, &lg->lg_prealloc_list[order],
pa_inode_list) {
spin_lock(&tmp_pa->pa_lock);
@@ -4160,7 +4160,7 @@ static void ext4_mb_add_n_trim(struct ext4_allocation_context *ac)
if (!added)
list_add_tail_rcu(&pa->pa_inode_list,
&lg->lg_prealloc_list[order]);
- rcu_read_unlock();
+ spin_unlock(&lg->lg_prealloc_lock);
/* Now trim the list to be not more than 8 elements */
if (lg_prealloc_count > 8) {
--
1.7.1
--
To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
