ext3-statfs-2.6-rhel5.patch

非常经典的一个分布式系统

Index: linux-2.6.18-8.1.8/fs/ext3/super.c
===================================================================
--- linux-2.6.18-8.1.8.orig/fs/ext3/super.c
+++ linux-2.6.18-8.1.8/fs/ext3/super.c
@@ -2923,18 +2923,18 @@ static int ext3_statfs (struct dentry * 
 	struct super_block *sb = dentry->d_sb;
 	struct ext3_sb_info *sbi = EXT3_SB(sb);
 	struct ext3_super_block *es = sbi->s_es;
-	ext3_fsblk_t overhead;
-	int i;
 
-	if (test_opt (sb, MINIX_DF))
-		overhead = 0;
-	else {
-		unsigned long ngroups;
-		ngroups = EXT3_SB(sb)->s_groups_count;
+	if (test_opt(sb, MINIX_DF)) {
+		sbi->s_overhead_last = 0;
+	} else if (sbi->s_blocks_last != le32_to_cpu(es->s_blocks_count)) {
+		unsigned long ngroups = sbi->s_groups_count, i;
+		ext3_fsblk_t overhead = 0;
 		smp_rmb();
 
 		/*
-		 * Compute the overhead (FS structures)
+		 * Compute the overhead (FS structures).  This is constant
+		 * for a given filesystem unless the number of block groups
+		 * changes so we cache the previous value until it does.
 		 */
 
 		/*
@@ -2956,18 +2956,23 @@ static int ext3_statfs (struct dentry * 
 		 * Every block group has an inode bitmap, a block
 		 * bitmap, and an inode table.
 		 */
-		overhead += (ngroups * (2 + EXT3_SB(sb)->s_itb_per_group));
+		overhead += ngroups * (2 + sbi->s_itb_per_group);
+		sbi->s_overhead_last = overhead;
+		smp_wmb();
+		sbi->s_blocks_last = le32_to_cpu(es->s_blocks_count);
 	}
 
 	buf->f_type = EXT3_SUPER_MAGIC;
 	buf->f_bsize = sb->s_blocksize;
-	buf->f_blocks = le32_to_cpu(es->s_blocks_count) - overhead;
+	buf->f_blocks = le32_to_cpu(es->s_blocks_count) - sbi->s_overhead_last;
 	buf->f_bfree = percpu_counter_sum(&sbi->s_freeblocks_counter);
+	es->s_free_blocks_count = cpu_to_le32(buf->f_bfree);
 	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 = percpu_counter_sum(&sbi->s_freeinodes_counter);
+	es->s_free_inodes_count = cpu_to_le32(buf->f_ffree);
 	buf->f_namelen = EXT3_NAME_LEN;
 	return 0;
 }
Index: linux-2.6.18-8.1.8/include/linux/ext3_fs_sb.h
===================================================================
--- linux-2.6.18-8.1.8.orig/include/linux/ext3_fs_sb.h
+++ linux-2.6.18-8.1.8/include/linux/ext3_fs_sb.h
@@ -45,6 +45,8 @@ struct ext3_sb_info {
 	unsigned long s_gdb_count;	/* Number of group descriptor blocks */
 	unsigned long s_desc_per_block;	/* Number of group descriptors per block */
 	unsigned long s_groups_count;	/* Number of groups in the fs */
+	unsigned long s_overhead_last;  /* Last calculated overhead */
+	unsigned long s_blocks_last;    /* Last seen block count */
 	struct buffer_head * s_sbh;	/* Buffer containing the super block */
 	struct ext3_super_block * s_es;	/* Pointer to the super block in the buffer */
 	struct buffer_head ** s_group_desc;