Protect inodes_stat statistics with atomic ops rather than inode_lock. Signed-off-by: Nick Piggin --- fs/fs-writeback.c | 6 ++++-- fs/inode.c | 28 +++++++++++++++------------- include/linux/fs.h | 5 +++-- 3 files changed, 22 insertions(+), 17 deletions(-) Index: linux-2.6/fs/fs-writeback.c =================================================================== --- linux-2.6.orig/fs/fs-writeback.c +++ linux-2.6/fs/fs-writeback.c @@ -924,7 +924,8 @@ static long wb_check_old_data_flush(stru wb->last_old_flush = jiffies; nr_pages = global_page_state(NR_FILE_DIRTY) + global_page_state(NR_UNSTABLE_NFS) + - (inodes_stat.nr_inodes - inodes_stat.nr_unused); + (atomic_read(&inodes_stat.nr_inodes) - + atomic_read(&inodes_stat.nr_unused)); if (nr_pages) { struct wb_writeback_args args = { @@ -1285,7 +1286,8 @@ void writeback_inodes_sb(struct super_bl long nr_to_write; nr_to_write = nr_dirty + nr_unstable + - (inodes_stat.nr_inodes - inodes_stat.nr_unused); + (atomic_read(&inodes_stat.nr_inodes) - + atomic_read(&inodes_stat.nr_unused)); bdi_start_writeback(sb->s_bdi, sb, nr_to_write); } Index: linux-2.6/fs/inode.c =================================================================== --- linux-2.6.orig/fs/inode.c +++ linux-2.6/fs/inode.c @@ -123,7 +123,10 @@ static DECLARE_RWSEM(iprune_sem); /* * Statistics gathering.. */ -struct inodes_stat_t inodes_stat; +struct inodes_stat_t inodes_stat = { + .nr_inodes = ATOMIC_INIT(0), + .nr_unused = ATOMIC_INIT(0), +}; static struct kmem_cache *inode_cachep __read_mostly; @@ -318,7 +321,7 @@ void __iget(struct inode *inode) list_move(&inode->i_list, &inode_in_use); spin_unlock(&wb_inode_list_lock); } - inodes_stat.nr_unused--; + atomic_dec(&inodes_stat.nr_unused); } /** @@ -382,9 +385,7 @@ static void dispose_list(struct list_hea destroy_inode(inode); nr_disposed++; } - spin_lock(&inode_lock); - inodes_stat.nr_inodes -= nr_disposed; - spin_unlock(&inode_lock); + atomic_sub(nr_disposed, &inodes_stat.nr_inodes); } /* @@ -433,7 +434,7 @@ static int invalidate_list(struct list_h busy = 1; } /* only unused inodes may be cached with i_count zero */ - inodes_stat.nr_unused -= count; + atomic_sub(count, &inodes_stat.nr_unused); return busy; } @@ -551,7 +552,7 @@ again2: spin_unlock(&inode->i_lock); nr_pruned++; } - inodes_stat.nr_unused -= nr_pruned; + atomic_sub(nr_pruned, &inodes_stat.nr_unused); if (current_is_kswapd()) __count_vm_events(KSWAPD_INODESTEAL, reap); else @@ -584,7 +585,8 @@ static int shrink_icache_memory(int nr, return -1; prune_icache(nr); } - return (inodes_stat.nr_unused / 100) * sysctl_vfs_cache_pressure; + return (atomic_read(&inodes_stat.nr_unused) / 100) * + sysctl_vfs_cache_pressure; } static struct shrinker icache_shrinker = { @@ -677,7 +679,7 @@ static inline void __inode_add_to_lists(struct super_block *sb, struct hlist_head *head, struct inode *inode) { - inodes_stat.nr_inodes++; + atomic_inc(&inodes_stat.nr_inodes); spin_lock(&sb_inode_list_lock); list_add(&inode->i_sb_list, &sb->s_inodes); spin_unlock(&sb_inode_list_lock); @@ -1321,8 +1323,8 @@ void generic_delete_inode(struct inode * WARN_ON(inode->i_state & I_NEW); inode->i_state |= I_FREEING; spin_unlock(&inode->i_lock); - inodes_stat.nr_inodes--; spin_unlock(&inode_lock); + atomic_dec(&inodes_stat.nr_inodes); if (op->delete_inode) { void (*delete)(struct inode *) = op->delete_inode; @@ -1365,7 +1367,7 @@ int generic_detach_inode(struct inode *i list_move(&inode->i_list, &inode_unused); spin_unlock(&wb_inode_list_lock); } - inodes_stat.nr_unused++; + atomic_inc(&inodes_stat.nr_unused); if (sb->s_flags & MS_ACTIVE) { spin_unlock(&inode->i_lock); spin_unlock(&sb_inode_list_lock); @@ -1383,7 +1385,7 @@ int generic_detach_inode(struct inode *i spin_lock(&inode->i_lock); WARN_ON(inode->i_state & I_NEW); inode->i_state &= ~I_WILL_FREE; - inodes_stat.nr_unused--; + atomic_dec(&inodes_stat.nr_unused); spin_lock(&inode_hash_lock); hlist_del_init(&inode->i_hash); spin_unlock(&inode_hash_lock); @@ -1395,9 +1397,9 @@ int generic_detach_inode(struct inode *i spin_unlock(&sb_inode_list_lock); WARN_ON(inode->i_state & I_NEW); inode->i_state |= I_FREEING; - inodes_stat.nr_inodes--; spin_unlock(&inode->i_lock); spin_unlock(&inode_lock); + atomic_dec(&inodes_stat.nr_inodes); return 1; } EXPORT_SYMBOL_GPL(generic_detach_inode); Index: linux-2.6/include/linux/fs.h =================================================================== --- linux-2.6.orig/include/linux/fs.h +++ linux-2.6/include/linux/fs.h @@ -38,13 +38,6 @@ struct files_stat_struct { int max_files; /* tunable */ }; -struct inodes_stat_t { - int nr_inodes; - int nr_unused; - int dummy[5]; /* padding for sysctl ABI compatibility */ -}; - - #define NR_FILE 8192 /* this can well be larger on a larger system */ #define MAY_EXEC 1 @@ -418,6 +411,12 @@ typedef int (get_block_t)(struct inode * typedef void (dio_iodone_t)(struct kiocb *iocb, loff_t offset, ssize_t bytes, void *private); +struct inodes_stat_t { + atomic_t nr_inodes; + atomic_t nr_unused; + int dummy[5]; /* padding for sysctl ABI compatibility */ +}; + /* * Attribute flags. These should be or-ed together to figure out what * has been changed! Index: linux-2.6/drivers/staging/pohmelfs/inode.c =================================================================== --- linux-2.6.orig/drivers/staging/pohmelfs/inode.c +++ linux-2.6/drivers/staging/pohmelfs/inode.c @@ -1283,11 +1283,11 @@ static void pohmelfs_put_super(struct su dprintk("%s: ino: %llu, pi: %p, inode: %p, count: %u.\n", __func__, pi->ino, pi, inode, count); - if (atomic_read(&inode->i_count) != count) { + if (inode->i_count != count) { printk("%s: ino: %llu, pi: %p, inode: %p, count: %u, i_count: %d.\n", __func__, pi->ino, pi, inode, count, - atomic_read(&inode->i_count)); - count = atomic_read(&inode->i_count); + inode->i_count); + count = inode->i_count; in_drop_list++; } @@ -1299,7 +1299,7 @@ static void pohmelfs_put_super(struct su pi = POHMELFS_I(inode); dprintk("%s: ino: %llu, pi: %p, inode: %p, i_count: %u.\n", - __func__, pi->ino, pi, inode, atomic_read(&inode->i_count)); + __func__, pi->ino, pi, inode, inode->i_count); /* * These are special inodes, they were created during @@ -1307,7 +1307,7 @@ static void pohmelfs_put_super(struct su * so they live here with reference counter being 1 and prevent * umount from succeed since it believes that they are busy. */ - count = atomic_read(&inode->i_count); + count = inode->i_count; if (count) { list_del_init(&inode->i_sb_list); while (count--) Index: linux-2.6/fs/btrfs/inode.c =================================================================== --- linux-2.6.orig/fs/btrfs/inode.c +++ linux-2.6/fs/btrfs/inode.c @@ -1964,8 +1964,13 @@ void btrfs_add_delayed_iput(struct inode struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info; struct delayed_iput *delayed; - if (atomic_add_unless(&inode->i_count, -1, 1)) + spin_lock(&inode->i_lock); + if (inode->i_count > 1) { + inode->i_count--; + spin_unlock(&inode->i_lock); return; + } + spin_unlock(&inode->i_lock); delayed = kmalloc(sizeof(*delayed), GFP_NOFS | __GFP_NOFAIL); delayed->inode = inode; @@ -2718,10 +2723,10 @@ static struct btrfs_trans_handle *__unli return ERR_PTR(-ENOSPC); /* check if there is someone else holds reference */ - if (S_ISDIR(inode->i_mode) && atomic_read(&inode->i_count) > 1) + if (S_ISDIR(inode->i_mode) && inode->i_count > 1) return ERR_PTR(-ENOSPC); - if (atomic_read(&inode->i_count) > 2) + if (inode->i_count > 2) return ERR_PTR(-ENOSPC); if (xchg(&root->fs_info->enospc_unlink, 1)) @@ -3934,7 +3939,7 @@ again: inode = igrab(&entry->vfs_inode); if (inode) { spin_unlock(&root->inode_lock); - if (atomic_read(&inode->i_count) > 1) + if (inode->i_count > 1) d_prune_aliases(inode); /* * btrfs_drop_inode will remove it from Index: linux-2.6/fs/ceph/mds_client.c =================================================================== --- linux-2.6.orig/fs/ceph/mds_client.c +++ linux-2.6/fs/ceph/mds_client.c @@ -1028,7 +1028,7 @@ static int trim_caps_cb(struct inode *in spin_unlock(&inode->i_lock); d_prune_aliases(inode); dout("trim_caps_cb %p cap %p pruned, count now %d\n", - inode, cap, atomic_read(&inode->i_count)); + inode, cap, inode->i_count); return 0; } Index: linux-2.6/fs/logfs/dir.c =================================================================== --- linux-2.6.orig/fs/logfs/dir.c +++ linux-2.6/fs/logfs/dir.c @@ -566,7 +566,9 @@ static int logfs_link(struct dentry *old return -EMLINK; inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; - atomic_inc(&inode->i_count); + spin_lock(&inode->i_lock); + inode->i_count++; + spin_unlock(&inode->i_lock); inode->i_nlink++; mark_inode_dirty_sync(inode); Index: linux-2.6/fs/logfs/readwrite.c =================================================================== --- linux-2.6.orig/fs/logfs/readwrite.c +++ linux-2.6/fs/logfs/readwrite.c @@ -1002,7 +1002,7 @@ static int __logfs_is_valid_block(struct { struct logfs_inode *li = logfs_inode(inode); - if ((inode->i_nlink == 0) && atomic_read(&inode->i_count) == 1) + if (inode->i_nlink == 0 && inode->i_count == 1) return 0; if (bix < I0_BLOCKS) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/