From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from userp1040.oracle.com ([156.151.31.81]:50622 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750897AbaGGSiy (ORCPT ); Mon, 7 Jul 2014 14:38:54 -0400 Received: from ucsinet21.oracle.com (ucsinet21.oracle.com [156.151.31.93]) by userp1040.oracle.com (Sentrion-MTA-4.3.2/Sentrion-MTA-4.3.2) with ESMTP id s67IcrwA010570 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Mon, 7 Jul 2014 18:38:53 GMT Received: from aserz7021.oracle.com (aserz7021.oracle.com [141.146.126.230]) by ucsinet21.oracle.com (8.14.4+Sun/8.14.4) with ESMTP id s67IcqWp016290 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Mon, 7 Jul 2014 18:38:53 GMT Received: from abhmp0015.oracle.com (abhmp0015.oracle.com [141.146.116.21]) by aserz7021.oracle.com (8.14.4+Sun/8.14.4) with ESMTP id s67IcqCc011641 for ; Mon, 7 Jul 2014 18:38:52 GMT From: Anand Jain To: linux-btrfs@vger.kernel.org Subject: [PATCH RFC] btrfs: code optimize use btrfs_get_bdev_and_sb() at btrfs_scan_one_device Date: Tue, 8 Jul 2014 02:38:37 +0800 Message-Id: <1404758317-7000-1-git-send-email-Anand.Jain@oracle.com> Sender: linux-btrfs-owner@vger.kernel.org List-ID: (for review comments pls). btrfs_scan_one_device() needs SB, instead of doing it from scratch could use btrfs_get_bdev_and_sb() Signed-off-by: Anand Jain --- fs/btrfs/volumes.c | 51 ++++++--------------------------------------------- 1 file changed, 6 insertions(+), 45 deletions(-) diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index c166355..94e6131 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -1053,14 +1053,11 @@ int btrfs_scan_one_device(const char *path, fmode_t flags, void *holder, { struct btrfs_super_block *disk_super; struct block_device *bdev; - struct page *page; - void *p; int ret = -EINVAL; u64 devid; u64 transid; u64 total_devices; - u64 bytenr; - pgoff_t index; + struct buffer_head *bh; /* * we would like to check all the supers, but that would make @@ -1068,44 +1065,12 @@ int btrfs_scan_one_device(const char *path, fmode_t flags, void *holder, * So, we need to add a special mount option to scan for * later supers, using BTRFS_SUPER_MIRROR_MAX instead */ - bytenr = btrfs_sb_offset(0); mutex_lock(&uuid_mutex); - bdev = blkdev_get_by_path(path, flags, holder); - - if (IS_ERR(bdev)) { - ret = PTR_ERR(bdev); + ret = btrfs_get_bdev_and_sb(path, flags, holder, 0, &bdev, &bh); + if (ret) goto error; - } - - /* make sure our super fits in the device */ - if (bytenr + PAGE_CACHE_SIZE >= i_size_read(bdev->bd_inode)) - goto error_bdev_put; - - /* make sure our super fits in the page */ - if (sizeof(*disk_super) > PAGE_CACHE_SIZE) - goto error_bdev_put; - - /* make sure our super doesn't straddle pages on disk */ - index = bytenr >> PAGE_CACHE_SHIFT; - if ((bytenr + sizeof(*disk_super) - 1) >> PAGE_CACHE_SHIFT != index) - goto error_bdev_put; - - /* pull in the page with our super */ - page = read_cache_page_gfp(bdev->bd_inode->i_mapping, - index, GFP_NOFS); - - if (IS_ERR_OR_NULL(page)) - goto error_bdev_put; - - p = kmap(page); - - /* align our pointer to the offset of the super block */ - disk_super = p + (bytenr & ~PAGE_CACHE_MASK); - - if (btrfs_super_bytenr(disk_super) != bytenr || - btrfs_super_magic(disk_super) != BTRFS_MAGIC) - goto error_unmap; + disk_super = (struct btrfs_super_block *) bh->b_data; devid = btrfs_stack_device_id(&disk_super->dev_item); transid = btrfs_super_generation(disk_super); @@ -1125,13 +1090,9 @@ int btrfs_scan_one_device(const char *path, fmode_t flags, void *holder, printk(KERN_CONT "devid %llu transid %llu %s\n", devid, transid, path); } - -error_unmap: - kunmap(page); - page_cache_release(page); - -error_bdev_put: + brelse(bh); blkdev_put(bdev, flags); + error: mutex_unlock(&uuid_mutex); return ret; -- 2.0.0.257.g75cc6c6