Re: [PATCH 08/18] xfs: remove xfs_reflink_find_cow_mapping

Brian Foster
2018-05-31T13:46:45Z

On Wed, May 30, 2018 at 12:00:03PM +0200, Christoph Hellwig wrote:
> We only have one caller left, and open coding the simple extent list
> lookup in it allows us to make the code both more understandable and
> reuse calculations and variables already present.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---

Reviewed-by: Brian Foster <bfoster@redhat.com>

> fs/xfs/xfs_aops.c | 17 ++++++++++++-----
> fs/xfs/xfs_reflink.c | 30 ------------------------------
> fs/xfs/xfs_reflink.h | 2 --
> fs/xfs/xfs_trace.h | 1 -
> 4 files changed, 12 insertions(+), 38 deletions(-)
>
> diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
> index 8cc41a786b5e..e2671b223409 100644
> --- a/fs/xfs/xfs_aops.c
> +++ b/fs/xfs/xfs_aops.c
> @@ -385,6 +385,7 @@ xfs_map_blocks(
> ssize_t count = i_blocksize(inode);
> xfs_fileoff_t offset_fsb, end_fsb;
> int whichfork = XFS_DATA_FORK;
> + struct xfs_iext_cursor icur;
> int error = 0;
> int nimaps = 1;
>
> @@ -396,8 +397,18 @@ xfs_map_blocks(
> (ip->i_df.if_flags & XFS_IFEXTENTS));
> ASSERT(offset <= mp->m_super->s_maxbytes);
>
> + if (offset > mp->m_super->s_maxbytes - count)
> + count = mp->m_super->s_maxbytes - offset;
> + end_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)offset + count);
> + offset_fsb = XFS_B_TO_FSBT(mp, offset);
> +
> + /*
> + * Check if this is offset is covered by a COW extents, and if yes use
> + * it directly instead of looking up anything in the data fork.
> + */
> if (xfs_is_reflink_inode(ip) &&
> - xfs_reflink_find_cow_mapping(ip, offset, imap)) {
> + xfs_iext_lookup_extent(ip, ip->i_cowfp, offset_fsb, &icur, imap) &&
> + imap->br_startoff <= offset_fsb) {
> xfs_iunlock(ip, XFS_ILOCK_SHARED);
> /*
> * Truncate can race with writeback since writeback doesn't
> @@ -417,10 +428,6 @@ xfs_map_blocks(
> goto allocate_blocks;
> }
>
> - if (offset > mp->m_super->s_maxbytes - count)
> - count = mp->m_super->s_maxbytes - offset;
> - end_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)offset + count);
> - offset_fsb = XFS_B_TO_FSBT(mp, offset);
> error = xfs_bmapi_read(ip, offset_fsb, end_fsb - offset_fsb,
> imap, &nimaps, XFS_BMAPI_ENTIRE);
> if (!nimaps) {
> diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c
> index 713e857d9ffa..8e5eb8e70c89 100644
> --- a/fs/xfs/xfs_reflink.c
> +++ b/fs/xfs/xfs_reflink.c
> @@ -484,36 +484,6 @@ xfs_reflink_allocate_cow(
> return error;
> }
>
> -/*
> - * Find the CoW reservation for a given byte offset of a file.
> - */
> -bool
> -xfs_reflink_find_cow_mapping(
> - struct xfs_inode *ip,
> - xfs_off_t offset,
> - struct xfs_bmbt_irec *imap)
> -{
> - struct xfs_ifork *ifp = XFS_IFORK_PTR(ip, XFS_COW_FORK);
> - xfs_fileoff_t offset_fsb;
> - struct xfs_bmbt_irec got;
> - struct xfs_iext_cursor icur;
> -
> - ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL | XFS_ILOCK_SHARED));
> -
> - if (!xfs_is_reflink_inode(ip))
> - return false;
> - offset_fsb = XFS_B_TO_FSBT(ip->i_mount, offset);
> - if (!xfs_iext_lookup_extent(ip, ifp, offset_fsb, &icur, &got))
> - return false;
> - if (got.br_startoff > offset_fsb)
> - return false;
> -
> - trace_xfs_reflink_find_cow_mapping(ip, offset, 1, XFS_IO_OVERWRITE,
> - &got);
> - *imap = got;
> - return true;
> -}
> -
> /*
> * Trim an extent to end at the next CoW reservation past offset_fsb.
> */
> diff --git a/fs/xfs/xfs_reflink.h b/fs/xfs/xfs_reflink.h
> index 701487bab468..15a456492667 100644
> --- a/fs/xfs/xfs_reflink.h
> +++ b/fs/xfs/xfs_reflink.h
> @@ -32,8 +32,6 @@ extern int xfs_reflink_allocate_cow(struct xfs_inode *ip,
> struct xfs_bmbt_irec *imap, bool *shared, uint *lockmode);
> extern int xfs_reflink_convert_cow(struct xfs_inode *ip, xfs_off_t offset,
> xfs_off_t count);
> -extern bool xfs_reflink_find_cow_mapping(struct xfs_inode *ip, xfs_off_t offset,
> - struct xfs_bmbt_irec *imap);
> extern void xfs_reflink_trim_irec_to_next_cow(struct xfs_inode *ip,
> xfs_fileoff_t offset_fsb, struct xfs_bmbt_irec *imap);
>
> diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h
> index 9d4c4ca24fe6..ed8f774944ba 100644
> --- a/fs/xfs/xfs_trace.h
> +++ b/fs/xfs/xfs_trace.h
> @@ -3227,7 +3227,6 @@ DEFINE_INODE_IREC_EVENT(xfs_reflink_convert_cow);
> DEFINE_RW_EVENT(xfs_reflink_reserve_cow);
>
> DEFINE_SIMPLE_IO_EVENT(xfs_reflink_bounce_dio_write);
> -DEFINE_IOMAP_EVENT(xfs_reflink_find_cow_mapping);
> DEFINE_INODE_IREC_EVENT(xfs_reflink_trim_irec);
>
> DEFINE_SIMPLE_IO_EVENT(xfs_reflink_cancel_cow_range);