[PATCH] ext2 statfs improvement for block and inode free count

[Badari Pulavarty <pbadari@us.ibm.com>]

Andrew,

Can you include it in -mm ? 

BTW, this patch is against mainline, won't apply cleanly to -mm, due to
other statfs() improvements.

Thanks,
Badari

More statfs() improvements for ext2. ext2 already maintains
percpu counters for free blocks and inodes. Derive free
block count and inode count by summing up percpu counters,
instead of counting up all the groups in the filesystem
each time.


Signed-off-by: Badari Pulavarty <pbadari@us.ibm.com>
Acked-by: Andreas Dilger <adilger@clusterfs.com>

 fs/ext2/super.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Index: linux-2.6.22/fs/ext2/super.c
===================================================================
--- linux-2.6.22.orig/fs/ext2/super.c	2007-07-13 20:06:38.000000000 -0700
+++ linux-2.6.22/fs/ext2/super.c	2007-07-13 20:06:51.000000000 -0700
@@ -1136,12 +1136,12 @@ static int ext2_statfs (struct dentry * 
 	buf->f_type = EXT2_SUPER_MAGIC;
 	buf->f_bsize = sb->s_blocksize;
 	buf->f_blocks = le32_to_cpu(es->s_blocks_count) - overhead;
-	buf->f_bfree = ext2_count_free_blocks(sb);
+ 	buf->f_bfree = percpu_counter_sum(&sbi->s_freeblocks_counter);
 	buf->f_bavail = buf->f_bfree - le32_to_cpu(es->s_r_blocks_count);
 	if (buf->f_bfree < le32_to_cpu(es->s_r_blocks_count))
 		buf->f_bavail = 0;
 	buf->f_files = le32_to_cpu(es->s_inodes_count);
-	buf->f_ffree = ext2_count_free_inodes(sb);
+ 	buf->f_ffree = percpu_counter_sum(&sbi->s_freeinodes_counter);
 	buf->f_namelen = EXT2_NAME_LEN;
 	fsid = le64_to_cpup((void *)es->s_uuid) ^
 	       le64_to_cpup((void *)es->s_uuid + sizeof(u64));


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