BACKPORT: bdi: initialize ->ra_pages and ->io_pages in bdi_init

Set up a readahead size by default, as very few users have a good
reason to change it.  This means code, ecryptfs, and orangefs now
set up the values while they were previously missing it, while ubifs,
mtd and vboxsf manually set it to 0 to avoid readahead.

Change-Id: I2394fea47e8685f26aee9cc52c72018cd2715741
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Acked-by: David Sterba <dsterba@suse.com> [btrfs]
Acked-by: Richard Weinberger <richard@nod.at> [ubifs, mtd]
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block/blk-core.c

@@ -1036,8 +1036,6 @@ struct request_queue *blk_alloc_queue_node(gfp_t gfp_mask, int node_id,
 	if (!q->stats)
 		goto fail_stats;
 
-	q->backing_dev_info->ra_pages = VM_READAHEAD_PAGES;
-	q->backing_dev_info->io_pages = VM_READAHEAD_PAGES;
 	q->backing_dev_info->capabilities = BDI_CAP_CGROUP_WRITEBACK;
 	q->backing_dev_info->name = "block";
 	q->node = node_id;

drivers/mtd/mtdcore.c

@@ -1867,6 +1867,8 @@ static struct backing_dev_info * __init mtd_bdi_init(char *name)
 	bdi = bdi_alloc(GFP_KERNEL);
 	if (!bdi)
 		return ERR_PTR(-ENOMEM);
+	bdi->ra_pages = 0;
+	bdi->io_pages = 0;
 
 	bdi->name = name;
 	/*

fs/9p/vfs_super.c

@@ -91,8 +91,10 @@ v9fs_fill_super(struct super_block *sb, struct v9fs_session_info *v9ses,
 	if (ret)
 		return ret;
 
-	if (v9ses->cache)
-		sb->s_bdi->ra_pages = VM_READAHEAD_PAGES;
+	if (!v9ses->cache) {
+		sb->s_bdi->ra_pages = 0;
+		sb->s_bdi->io_pages = 0;
+	}
 
 	sb->s_flags |= SB_ACTIVE | SB_DIRSYNC;
 	if (!v9ses->cache)

fs/afs/super.c

@@ -442,7 +442,6 @@ static int afs_fill_super(struct super_block *sb, struct afs_fs_context *ctx)
 	ret = super_setup_bdi(sb);
 	if (ret)
 		return ret;
-	sb->s_bdi->ra_pages	= VM_READAHEAD_PAGES;
 
 	/* allocate the root inode and dentry */
 	if (as->dyn_root) {

fs/btrfs/disk-io.c

@@ -2944,7 +2944,6 @@ int open_ctree(struct super_block *sb,
 	sb->s_bdi->congested_fn = btrfs_congested_fn;
 	sb->s_bdi->congested_data = fs_info;
 	sb->s_bdi->capabilities |= BDI_CAP_CGROUP_WRITEBACK;
-	sb->s_bdi->ra_pages = VM_READAHEAD_PAGES;
 	sb->s_bdi->ra_pages *= btrfs_super_num_devices(disk_super);
 	sb->s_bdi->ra_pages = max(sb->s_bdi->ra_pages, SZ_4M / PAGE_SIZE);
 

fs/fuse/inode.c

@@ -1167,7 +1167,6 @@ static int fuse_bdi_init(struct fuse_conn *fc, struct super_block *sb)
 	if (err)
 		return err;
 
-	sb->s_bdi->ra_pages = VM_READAHEAD_PAGES;
 	/* fuse does it's own writeback accounting */
 	sb->s_bdi->capabilities = BDI_CAP_NO_ACCT_WB | BDI_CAP_STRICTLIMIT;
 

fs/ubifs/super.c

@@ -2087,6 +2087,8 @@ static int ubifs_fill_super(struct super_block *sb, void *data, int silent)
 				   c->vi.vol_id);
 	if (err)
 		goto out_close;
+	sb->s_bdi->ra_pages = 0;
+	sb->s_bdi->io_pages = 0;
 
 	sb->s_fs_info = c;
 	sb->s_magic = UBIFS_SUPER_MAGIC;

mm/backing-dev.c

@@ -869,6 +869,8 @@ struct backing_dev_info *bdi_alloc_node(gfp_t gfp_mask, int node_id)
 		kfree(bdi);
 		return NULL;
 	}
+	bdi->ra_pages = VM_READAHEAD_PAGES;
+	bdi->io_pages = VM_READAHEAD_PAGES;
 	return bdi;
 }
 EXPORT_SYMBOL(bdi_alloc_node);