On Tue, Jul 08, 2014 at 02:38:37AM +0800, Anand Jain wrote: > (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 <[email protected]> > --- > 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;
Apparently btrfs_get_bdev_and_sb() lacks the above two checks, otherwise looks good. thanks, -liubo > - > - /* 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 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > the body of a message to [email protected] > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
