On Mon, Feb 27, 2017 at 04:49:10PM -0800, Christoph Hellwig wrote:
> We only want to reclaim preallocations from our periodic work item.
> Currenrly this is archived by looking for a diry inode, but that check
> is rather fragile. Instead add flags to the xfs_reflink_cancel_cow_* so
> that the caller can ask for just cancelling unwritten extents in the COw
> fork.
>
> Signed-off-by: Christoph Hellwig <hch@xxxxxx>
> ---
> fs/xfs/xfs_aops.c | 2 +-
> fs/xfs/xfs_icache.c | 2 +-
> fs/xfs/xfs_inode.c | 2 +-
> fs/xfs/xfs_reflink.c | 14 +++++++++-----
> fs/xfs/xfs_reflink.h | 5 +++--
> fs/xfs/xfs_super.c | 2 +-
> 6 files changed, 16 insertions(+), 11 deletions(-)
>
> diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
> index b480647e00e7..290c0fb306e7 100644
> --- a/fs/xfs/xfs_aops.c
> +++ b/fs/xfs/xfs_aops.c
> @@ -293,7 +293,7 @@ xfs_end_io(
> goto done;
> if (ioend->io_bio->bi_error) {
> error = xfs_reflink_cancel_cow_range(ip,
> - ioend->io_offset, ioend->io_size);
> + ioend->io_offset, ioend->io_size, 0);
> goto done;
> }
> error = xfs_reflink_end_cow(ip, ioend->io_offset,
> diff --git a/fs/xfs/xfs_icache.c b/fs/xfs/xfs_icache.c
> index 7234b9748c36..1f7d158266c1 100644
> --- a/fs/xfs/xfs_icache.c
> +++ b/fs/xfs/xfs_icache.c
> @@ -1608,7 +1608,7 @@ xfs_inode_free_cowblocks(
> xfs_ilock(ip, XFS_IOLOCK_EXCL);
> xfs_ilock(ip, XFS_MMAPLOCK_EXCL);
>
> - ret = xfs_reflink_cancel_cow_range(ip, 0, NULLFILEOFF);
> + ret = xfs_reflink_cancel_cow_range(ip, 0, NULLFILEOFF, XFS_CC_UNWRITTEN);
Ok, so the periodic work item leaves real cow extents alone now, which
is good since real extents now represent pending cow operations. Good.
> xfs_iunlock(ip, XFS_MMAPLOCK_EXCL);
> xfs_iunlock(ip, XFS_IOLOCK_EXCL);
> diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
> index edfa6a55b064..164e74a511b1 100644
> --- a/fs/xfs/xfs_inode.c
> +++ b/fs/xfs/xfs_inode.c
> @@ -1615,7 +1615,7 @@ xfs_itruncate_extents(
>
> /* Remove all pending CoW reservations. */
> error = xfs_reflink_cancel_cow_blocks(ip, &tp, first_unmap_block,
> - last_block);
> + last_block, 0);
> if (error)
> goto out;
>
> diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c
> index 08ca9f81b087..83605af3b135 100644
> --- a/fs/xfs/xfs_reflink.c
> +++ b/fs/xfs/xfs_reflink.c
> @@ -551,7 +551,8 @@ xfs_reflink_cancel_cow_blocks(
> struct xfs_inode *ip,
> struct xfs_trans **tpp,
> xfs_fileoff_t offset_fsb,
> - xfs_fileoff_t end_fsb)
> + xfs_fileoff_t end_fsb,
> + unsigned flags)
> {
> struct xfs_ifork *ifp = XFS_IFORK_PTR(ip, XFS_COW_FORK);
> struct xfs_bmbt_irec got, del;
> @@ -575,7 +576,8 @@ xfs_reflink_cancel_cow_blocks(
> &idx, &got, &del);
> if (error)
> break;
> - } else {
> + } else if (del.br_state == XFS_EXT_UNWRITTEN ||
> + !(flags & XFS_CC_UNWRITTEN)) {
> xfs_trans_ijoin(*tpp, ip, 0);
> xfs_defer_init(&dfops, &firstfsb);
>
> @@ -623,7 +625,8 @@ int
> xfs_reflink_cancel_cow_range(
> struct xfs_inode *ip,
> xfs_off_t offset,
> - xfs_off_t count)
> + xfs_off_t count,
> + unsigned flags)
> {
> struct xfs_trans *tp;
> xfs_fileoff_t offset_fsb;
> @@ -649,7 +652,8 @@ xfs_reflink_cancel_cow_range(
> xfs_trans_ijoin(tp, ip, 0);
>
> /* Scrape out the old CoW reservations */
> - error = xfs_reflink_cancel_cow_blocks(ip, &tp, offset_fsb, end_fsb);
> + error = xfs_reflink_cancel_cow_blocks(ip, &tp, offset_fsb, end_fsb,
> + flags);
> if (error)
> goto out_cancel;
>
> @@ -1437,7 +1441,7 @@ xfs_reflink_clear_inode_flag(
> * We didn't find any shared blocks so turn off the reflink flag.
> * First, get rid of any leftover CoW mappings.
> */
> - error = xfs_reflink_cancel_cow_blocks(ip, tpp, 0, NULLFILEOFF);
> + error = xfs_reflink_cancel_cow_blocks(ip, tpp, 0, NULLFILEOFF, 0);
> if (error)
> return error;
>
> diff --git a/fs/xfs/xfs_reflink.h b/fs/xfs/xfs_reflink.h
> index 33ac9b8db683..9416279b3c89 100644
> --- a/fs/xfs/xfs_reflink.h
> +++ b/fs/xfs/xfs_reflink.h
> @@ -37,11 +37,12 @@ extern bool xfs_reflink_find_cow_mapping(struct xfs_inode *ip, xfs_off_t offset,
> extern void xfs_reflink_trim_irec_to_next_cow(struct xfs_inode *ip,
> xfs_fileoff_t offset_fsb, struct xfs_bmbt_irec *imap);
>
> +#define XFS_CC_UNWRITTEN 0x01
Could we have a comment here about what CC_UNWRITTEN means?
I /think/ it means "don't remove real extents", since when it's specified
delalloc reservations still get removed by _reflink_cancel_cow_*, correct?
Somewhere we ought to record the fact that flags == 0 removes everything.
--D
> extern int xfs_reflink_cancel_cow_blocks(struct xfs_inode *ip,
> struct xfs_trans **tpp, xfs_fileoff_t offset_fsb,
> - xfs_fileoff_t end_fsb);
> + xfs_fileoff_t end_fsb, unsigned flags);
> extern int xfs_reflink_cancel_cow_range(struct xfs_inode *ip, xfs_off_t offset,
> - xfs_off_t count);
> + xfs_off_t count, unsigned flags);
> extern int xfs_reflink_end_cow(struct xfs_inode *ip, xfs_off_t offset,
> xfs_off_t count);
> extern int xfs_reflink_recover_cow(struct xfs_mount *mp);
> diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
> index 890862f2447c..9136854030d5 100644
> --- a/fs/xfs/xfs_super.c
> +++ b/fs/xfs/xfs_super.c
> @@ -953,7 +953,7 @@ xfs_fs_destroy_inode(
> XFS_STATS_INC(ip->i_mount, vn_remove);
>
> if (xfs_is_reflink_inode(ip)) {
> - error = xfs_reflink_cancel_cow_range(ip, 0, NULLFILEOFF);
> + error = xfs_reflink_cancel_cow_range(ip, 0, NULLFILEOFF, 0);
> if (error && !XFS_FORCED_SHUTDOWN(ip->i_mount))
> xfs_warn(ip->i_mount,
> "Error %d while evicting CoW blocks for inode %llu.",
> --
> 2.11.0
>
> --
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