From: Dave Kleikamp Fix a performance degradation introduced in 2.6.17. (30% degradation running dbench with 16 threads) Patch 21730eed11de42f22afcbd43f450a1872a0b5ea1, which claims to make EXT2_DEBUG work again, moves the taking of the kernel lock out of debug-only code in ext2_count_free_inodes and ext2_count_free_blocks and into ext2_statfs. The same problem was fixed in ext3 by removing the lock completely (patch 5b11687924e40790deb0d5f959247ade82196665) Signed-off-by: Dave Kleikamp Signed-off-by: Andrew Morton --- fs/ext2/balloc.c | 1 - fs/ext2/ialloc.c | 1 - fs/ext2/super.c | 2 -- 3 files changed, 4 deletions(-) diff -puN fs/ext2/balloc.c~ext2-remove-superblock-lock-contention-in-ext2_statfs-2 fs/ext2/balloc.c --- a/fs/ext2/balloc.c~ext2-remove-superblock-lock-contention-in-ext2_statfs-2 +++ a/fs/ext2/balloc.c @@ -539,7 +539,6 @@ unsigned long ext2_count_free (struct bu #endif /* EXT2FS_DEBUG */ -/* Superblock must be locked */ unsigned long ext2_count_free_blocks (struct super_block * sb) { struct ext2_group_desc * desc; diff -puN fs/ext2/ialloc.c~ext2-remove-superblock-lock-contention-in-ext2_statfs-2 fs/ext2/ialloc.c --- a/fs/ext2/ialloc.c~ext2-remove-superblock-lock-contention-in-ext2_statfs-2 +++ a/fs/ext2/ialloc.c @@ -637,7 +637,6 @@ fail: return ERR_PTR(err); } -/* Superblock must be locked */ unsigned long ext2_count_free_inodes (struct super_block * sb) { struct ext2_group_desc *desc; diff -puN fs/ext2/super.c~ext2-remove-superblock-lock-contention-in-ext2_statfs-2 fs/ext2/super.c --- a/fs/ext2/super.c~ext2-remove-superblock-lock-contention-in-ext2_statfs-2 +++ a/fs/ext2/super.c @@ -1083,7 +1083,6 @@ static int ext2_statfs (struct dentry * unsigned long overhead; int i; - lock_super(sb); if (test_opt (sb, MINIX_DF)) overhead = 0; else { @@ -1124,7 +1123,6 @@ static int ext2_statfs (struct dentry * buf->f_files = le32_to_cpu(sbi->s_es->s_inodes_count); buf->f_ffree = ext2_count_free_inodes (sb); buf->f_namelen = EXT2_NAME_LEN; - unlock_super(sb); return 0; } _