2007-10-25 20:10:52

by Eric Sandeen

[permalink] [raw]
Subject: [PATCH] ext4: fix freespace accounting with mballoc on 32bit machines

On a 32bit machine, passing the negative unsigned long fe_len
into percpu_counter_add (which expects s64) messes up the counters:

[[email protected] linux-2.6.23-rc7]# df -h

Filesystem Size Used Avail Use% Mounted on
/dev/sdb7 97G -149P 149P - /mnt/test

Patch below fixes this.

Signed-off-by: Eric Sandeen <[email protected]>

--- linux.orig/fs/ext4/mballoc.c 2007-10-25 14:47:25.048435451 -0500
+++ linux/fs/ext4/mballoc.c 2007-10-25 14:47:35.815160682 -0500
@@ -3005,7 +3005,7 @@
- ac->ac_b_ex.fe_len);
gdp->bg_checksum = ext4_group_desc_csum(sbi, ac->ac_b_ex.fe_group, gdp);
spin_unlock(sb_bgl_lock(sbi, ac->ac_b_ex.fe_group));
- percpu_counter_add(&sbi->s_freeblocks_counter, - ac->ac_b_ex.fe_len);
+ percpu_counter_sub(&sbi->s_freeblocks_counter, ac->ac_b_ex.fe_len);

err = ext4_journal_dirty_metadata(handle, bitmap_bh);
if (err)