Re: [PATCH 6/8] vfs: Make sys_sync writeout also block device inodes

From: Fengguang Wu
Date: Tue Jul 17 2012 - 02:27:32 EST


Hi Jan,

I got this error for !CONFIG_BLOCK builds:

fs/sync.c:110:2: error: implicit declaration of function 'iterate_bdevs' [-Werror=implicit-function-declaration]

Thanks,
Fengguang

On Tue, Jul 03, 2012 at 04:45:32PM +0200, Jan Kara wrote:
> In case block device does not have filesystem mounted on it, sys_sync will just
> ignore it and doesn't writeout its dirty pages. This is because writeback code
> avoids writing inodes from superblock without backing device and
> blockdev_superblock is such a superblock. Since it's unexpected that sync
> doesn't writeout dirty data for block devices be nice to users and change the
> behavior to do so. So now we iterate over all block devices on blockdev_super
> instead of iterating over all superblocks when syncing block devices.
>
> Reviewed-by: Christoph Hellwig <hch@xxxxxx>
> Signed-off-by: Jan Kara <jack@xxxxxxx>
> ---
> fs/sync.c | 18 +++++++++++-------
> 1 files changed, 11 insertions(+), 7 deletions(-)
>
> diff --git a/fs/sync.c b/fs/sync.c
> index 867bf78..ea6e818 100644
> --- a/fs/sync.c
> +++ b/fs/sync.c
> @@ -85,10 +85,14 @@ static void sync_fs_one_sb(struct super_block *sb, void *arg)
> sb->s_op->sync_fs(sb, *(int *)arg);
> }
>
> -static void sync_blkdev_one_sb(struct super_block *sb, void *arg)
> +static void flush_one_bdev(struct block_device *bdev, void *arg)
> {
> - if (!(sb->s_flags & MS_RDONLY))
> - __sync_blockdev(sb->s_bdev, *(int *)arg);
> + __sync_blockdev(bdev, 0);
> +}
> +
> +static void sync_one_bdev(struct block_device *bdev, void *arg)
> +{
> + sync_blockdev(bdev);
> }
>
> /*
> @@ -102,10 +106,10 @@ SYSCALL_DEFINE0(sync)
> wakeup_flusher_threads(0, WB_REASON_SYNC);
> iterate_supers(writeback_inodes_one_sb, NULL);
> iterate_supers(sync_fs_one_sb, &nowait);
> - iterate_supers(sync_blkdev_one_sb, &nowait);
> + iterate_bdevs(flush_one_bdev, NULL);
> iterate_supers(sync_inodes_one_sb, NULL);
> iterate_supers(sync_fs_one_sb, &wait);
> - iterate_supers(sync_blkdev_one_sb, &wait);
> + iterate_bdevs(sync_one_bdev, NULL);
> if (unlikely(laptop_mode))
> laptop_sync_completion();
> return 0;
> @@ -121,10 +125,10 @@ static void do_sync_work(struct work_struct *work)
> */
> iterate_supers(sync_inodes_one_sb, &nowait);
> iterate_supers(sync_fs_one_sb, &nowait);
> - iterate_supers(sync_blkdev_one_sb, &nowait);
> + iterate_bdevs(flush_one_bdev, NULL);
> iterate_supers(sync_inodes_one_sb, &nowait);
> iterate_supers(sync_fs_one_sb, &nowait);
> - iterate_supers(sync_blkdev_one_sb, &nowait);
> + iterate_bdevs(flush_one_bdev, NULL);
> printk("Emergency Sync complete\n");
> kfree(work);
> }
> --
> 1.7.1
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@xxxxxxxxxxxxxxx
> More majordomo info at http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at http://www.tux.org/lkml/
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/