revert "percpu_counter: new function percpu_counter_sum_and_set"

Revert

    commit e8ced39d5e8911c662d4d69a342b9d053eaaac4e
    Author: Mingming Cao <cmm@us.ibm.com>
    Date:   Fri Jul 11 19:27:31 2008 -0400

        percpu_counter: new function percpu_counter_sum_and_set

As described in

	revert "percpu counter: clean up percpu_counter_sum_and_set()"

the new percpu_counter_sum_and_set() is racy against updates to the
cpu-local accumulators on other CPUs.  Revert that change.

This means that ext4 will be slow again.  But correct.

Reported-by: Eric Dumazet <dada1@cosmosbay.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mingming Cao <cmm@us.ibm.com>
Cc: <linux-ext4@vger.kernel.org>
Cc: <stable@kernel.org>		[2.6.27.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 2 insertions, 2 deletions

diff --git a/fs/ext4/balloc.c b/fs/ext4/balloc.c
index c17f69bcd7dd..db35cfdb3c8b 100644
--- a/fs/ext4/balloc.c
+++ b/fs/ext4/balloc.c
@@ -609,8 +609,8 @@ int ext4_has_free_blocks(struct ext4_sb_info *sbi, s64 nblocks)
 
         if (free_blocks - (nblocks + root_blocks + dirty_blocks) <
                                                 EXT4_FREEBLOCKS_WATERMARK) {
-                free_blocks  = percpu_counter_sum_and_set(fbc);
-                dirty_blocks = percpu_counter_sum_and_set(dbc);
+                free_blocks  = percpu_counter_sum_positive(fbc);
+                dirty_blocks = percpu_counter_sum_positive(dbc);
                 if (dirty_blocks < 0) {
                         printk(KERN_CRIT "Dirty block accounting "
                                         "went wrong %lld\n",