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, 11 insertions, 11 deletions

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index eb9d449817d0..7875a2dd54b9 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -1030,19 +1030,20 @@ static void ext4_da_update_reserve_space(struct inode *inode, int used)
         BUG_ON(mdb > EXT4_I(inode)->i_reserved_meta_blocks);
         mdb_free = EXT4_I(inode)->i_reserved_meta_blocks - mdb;
 
-        /* Account for allocated meta_blocks */
-        mdb_free -= EXT4_I(inode)->i_allocated_meta_blocks;
-
-        /* update fs free blocks counter for truncate case */
-        percpu_counter_add(&sbi->s_freeblocks_counter, mdb_free);
+        if (mdb_free) {
+                /* Account for allocated meta_blocks */
+                mdb_free -= EXT4_I(inode)->i_allocated_meta_blocks;
+
+                /* update fs dirty blocks counter */
+                percpu_counter_sub(&sbi->s_dirtyblocks_counter, mdb_free);
+                EXT4_I(inode)->i_allocated_meta_blocks = 0;
+                EXT4_I(inode)->i_reserved_meta_blocks = mdb;
+        }
 
         /* update per-inode reservations */
         BUG_ON(used  > EXT4_I(inode)->i_reserved_data_blocks);
         EXT4_I(inode)->i_reserved_data_blocks -= used;
 
-        BUG_ON(mdb > EXT4_I(inode)->i_reserved_meta_blocks);
-        EXT4_I(inode)->i_reserved_meta_blocks = mdb;
-        EXT4_I(inode)->i_allocated_meta_blocks = 0;
         spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
 }
 
@@ -1588,8 +1589,8 @@ static void ext4_da_release_space(struct inode *inode, int to_free)
 
         release = to_free + mdb_free;
 
-        /* update fs free blocks counter for truncate case */
-        percpu_counter_add(&sbi->s_freeblocks_counter, release);
+        /* update fs dirty blocks counter for truncate case */
+        percpu_counter_sub(&sbi->s_dirtyblocks_counter, release);
 
         /* update per-inode reservations */
         BUG_ON(to_free > EXT4_I(inode)->i_reserved_data_blocks);
@@ -2471,7 +2472,6 @@ static int ext4_da_write_begin(struct file *file, struct address_space *mapping,
         index = pos >> PAGE_CACHE_SHIFT;
         from = pos & (PAGE_CACHE_SIZE - 1);
         to = from + len;
-
 retry:
         /*
          * With delayed allocation, we don't log the i_disksize update