Re: [PATCH v3 4/6] dax: give DAX clearing code correct bdev

Jan Kara
2016-02-17T21:38:02Z

On Tue 16-02-16 20:34:17, Ross Zwisler wrote:
> dax_clear_blocks() needs a valid struct block_device and previously it was
> using inode->i_sb->s_bdev in all cases. This is correct for normal inodes
> on mounted ext2, ext4 and XFS filesystems, but is incorrect for DAX raw
> block devices and for XFS real-time devices.
>
> Instead, rename dax_clear_blocks() to dax_clear_sectors(), and change its
> arguments to take a bdev and a sector instead of an inode and a block.
> This better reflects what the function does, and it allows the filesystem
> and raw block device code to pass in an appropriate struct block_device.
>
> Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
> Suggested-by: Dan Williams <dan.j.williams@intel.com>

The patch looks good to me. You can add:

Reviewed-by: Jan Kara <jack@suse.cz>

Honza

> ---
> fs/dax.c | 9 ++++-----
> fs/ext2/inode.c | 6 ++++--
> fs/xfs/xfs_aops.c | 2 +-
> fs/xfs/xfs_aops.h | 1 +
> fs/xfs/xfs_bmap_util.c | 3 ++-
> include/linux/dax.h | 2 +-
> 6 files changed, 13 insertions(+), 10 deletions(-)
>
> diff --git a/fs/dax.c b/fs/dax.c
> index fc2e314..9a173dd 100644
> --- a/fs/dax.c
> +++ b/fs/dax.c
> @@ -79,15 +79,14 @@ struct page *read_dax_sector(struct block_device *bdev, sector_t n)
> }
>
> /*
> - * dax_clear_blocks() is called from within transaction context from XFS,
> + * dax_clear_sectors() is called from within transaction context from XFS,
> * and hence this means the stack from this point must follow GFP_NOFS
> * semantics for all operations.
> */
> -int dax_clear_blocks(struct inode *inode, sector_t block, long _size)
> +int dax_clear_sectors(struct block_device *bdev, sector_t _sector, long _size)
> {
> - struct block_device *bdev = inode->i_sb->s_bdev;
> struct blk_dax_ctl dax = {
> - .sector = block << (inode->i_blkbits - 9),
> + .sector = _sector,
> .size = _size,
> };
>
> @@ -109,7 +108,7 @@ int dax_clear_blocks(struct inode *inode, sector_t block, long _size)
> wmb_pmem();
> return 0;
> }
> -EXPORT_SYMBOL_GPL(dax_clear_blocks);
> +EXPORT_SYMBOL_GPL(dax_clear_sectors);
>
> /* the clear_pmem() calls are ordered by a wmb_pmem() in the caller */
> static void dax_new_buf(void __pmem *addr, unsigned size, unsigned first,
> diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c
> index 27e2cdd..4467cbd 100644
> --- a/fs/ext2/inode.c
> +++ b/fs/ext2/inode.c
> @@ -737,8 +737,10 @@ static int ext2_get_blocks(struct inode *inode,
> * so that it's not found by another thread before it's
> * initialised
> */
> - err = dax_clear_blocks(inode, le32_to_cpu(chain[depth-1].key),
> - 1 << inode->i_blkbits);
> + err = dax_clear_sectors(inode->i_sb->s_bdev,
> + le32_to_cpu(chain[depth-1].key) <<
> + (inode->i_blkbits - 9),
> + 1 << inode->i_blkbits);
> if (err) {
> mutex_unlock(&ei->truncate_mutex);
> goto cleanup;
> diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
> index 379c089..fc20518 100644
> --- a/fs/xfs/xfs_aops.c
> +++ b/fs/xfs/xfs_aops.c
> @@ -55,7 +55,7 @@ xfs_count_page_state(
> } while ((bh = bh->b_this_page) != head);
> }
>
> -STATIC struct block_device *
> +struct block_device *
> xfs_find_bdev_for_inode(
> struct inode *inode)
> {
> diff --git a/fs/xfs/xfs_aops.h b/fs/xfs/xfs_aops.h
> index f6ffc9a..a4343c6 100644
> --- a/fs/xfs/xfs_aops.h
> +++ b/fs/xfs/xfs_aops.h
> @@ -62,5 +62,6 @@ int xfs_get_blocks_dax_fault(struct inode *inode, sector_t offset,
> struct buffer_head *map_bh, int create);
>
> extern void xfs_count_page_state(struct page *, int *, int *);
> +extern struct block_device *xfs_find_bdev_for_inode(struct inode *);
>
> #endif /* __XFS_AOPS_H__ */
> diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c
> index 45ec9e4..6c87601 100644
> --- a/fs/xfs/xfs_bmap_util.c
> +++ b/fs/xfs/xfs_bmap_util.c
> @@ -75,7 +75,8 @@ xfs_zero_extent(
> ssize_t size = XFS_FSB_TO_B(mp, count_fsb);
>
> if (IS_DAX(VFS_I(ip)))
> - return dax_clear_blocks(VFS_I(ip), block, size);
> + return dax_clear_sectors(xfs_find_bdev_for_inode(VFS_I(ip)),
> + sector, size);
>
> /*
> * let the block layer decide on the fastest method of
> diff --git a/include/linux/dax.h b/include/linux/dax.h
> index 818e450..7b6bced 100644
> --- a/include/linux/dax.h
> +++ b/include/linux/dax.h
> @@ -7,7 +7,7 @@
>
> ssize_t dax_do_io(struct kiocb *, struct inode *, struct iov_iter *, loff_t,
> get_block_t, dio_iodone_t, int flags);
> -int dax_clear_blocks(struct inode *, sector_t block, long size);
> +int dax_clear_sectors(struct block_device *bdev, sector_t _sector, long _size);
> int dax_zero_page_range(struct inode *, loff_t from, unsigned len, get_block_t);
> int dax_truncate_page(struct inode *, loff_t from, get_block_t);
> int dax_fault(struct vm_area_struct *, struct vm_fault *, get_block_t,
> --
> 2.5.0
>
>
--
Jan Kara <jack@suse.com>
SUSE Labs, CR