ext4: Add percpu dirty block accounting.

This patch adds dirty block accounting using percpu_counters.  Delayed
allocation block reservation is now done by updating dirty block
counter.  In a later patch we switch to non delalloc mode if the
filesystem free blocks is greater than 150% of total filesystem dirty
blocks

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Mingming Cao<cmm@us.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

1 files changed, 7 insertions, 1 deletions

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 7de6ca0c9e9b..efa40d9d3792 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -520,6 +520,7 @@ static void ext4_put_super(struct super_block *sb)
         percpu_counter_destroy(&sbi->s_freeblocks_counter);
         percpu_counter_destroy(&sbi->s_freeinodes_counter);
         percpu_counter_destroy(&sbi->s_dirs_counter);
+        percpu_counter_destroy(&sbi->s_dirtyblocks_counter);
         brelse(sbi->s_sbh);
 #ifdef CONFIG_QUOTA
         for (i = 0; i < MAXQUOTAS; i++)
@@ -2259,6 +2260,9 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
                 err = percpu_counter_init(&sbi->s_dirs_counter,
                                 ext4_count_dirs(sb));
         }
+        if (!err) {
+                err = percpu_counter_init(&sbi->s_dirtyblocks_counter, 0);
+        }
         if (err) {
                 printk(KERN_ERR "EXT4-fs: insufficient memory\n");
                 goto failed_mount3;
@@ -2491,6 +2495,7 @@ failed_mount3:
         percpu_counter_destroy(&sbi->s_freeblocks_counter);
         percpu_counter_destroy(&sbi->s_freeinodes_counter);
         percpu_counter_destroy(&sbi->s_dirs_counter);
+        percpu_counter_destroy(&sbi->s_dirtyblocks_counter);
 failed_mount2:
         for (i = 0; i < db_count; i++)
                 brelse(sbi->s_group_desc[i]);
@@ -3169,7 +3174,8 @@ static int ext4_statfs(struct dentry *dentry, struct kstatfs *buf)
         buf->f_type = EXT4_SUPER_MAGIC;
         buf->f_bsize = sb->s_blocksize;
         buf->f_blocks = ext4_blocks_count(es) - sbi->s_overhead_last;
-        buf->f_bfree = percpu_counter_sum_positive(&sbi->s_freeblocks_counter);
+        buf->f_bfree = percpu_counter_sum_positive(&sbi->s_freeblocks_counter) -
+                       percpu_counter_sum_positive(&sbi->s_dirtyblocks_counter);
         ext4_free_blocks_count_set(es, buf->f_bfree);
         buf->f_bavail = buf->f_bfree - ext4_r_blocks_count(es);
         if (buf->f_bfree < ext4_r_blocks_count(es))