On Thu, May 24, 2018 at 10:59:43AM -0400, Brian Foster wrote:
> On Wed, May 23, 2018 at 04:43:48PM +0200, Christoph Hellwig wrote:
> > In the only caller we just did a lookup in the COW extent tree for
> > the same offset. Reuse that result and save a lookup, as well as
> > shortening the ilock hold time.
> >
> > Signed-off-by: Christoph Hellwig <hch@xxxxxx>
> > ---
> > fs/xfs/xfs_aops.c | 25 +++++++++++++++++--------
> > fs/xfs/xfs_reflink.c | 33 ---------------------------------
> > fs/xfs/xfs_reflink.h | 2 --
> > 3 files changed, 17 insertions(+), 43 deletions(-)
> >
> > diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
> > index a4b4a7037deb..354d26d66c12 100644
> > --- a/fs/xfs/xfs_aops.c
> > +++ b/fs/xfs/xfs_aops.c
> > @@ -383,11 +383,12 @@ xfs_map_blocks(
> > struct xfs_inode *ip = XFS_I(inode);
> > struct xfs_mount *mp = ip->i_mount;
> > ssize_t count = i_blocksize(inode);
> > - xfs_fileoff_t offset_fsb, end_fsb;
> > + xfs_fileoff_t offset_fsb, end_fsb, cow_fsb = 0;
>
> cow_fsb should probably be initialized to NULLFSBLOCK rather than 0.
> With that, you also shouldn't need cow_valid. Otherwise looks Ok to me.
>
Err.. I guess NULLFILEOFF would be more appropriate here, but same
idea..
> Brian
>
> > int whichfork = XFS_DATA_FORK;
> > struct xfs_iext_cursor icur;
> > int error = 0;
> > int nimaps = 1;
> > + bool cow_valid = false;
> >
> > if (XFS_FORCED_SHUTDOWN(mp))
> > return -EIO;
> > @@ -407,8 +408,11 @@ xfs_map_blocks(
> > * it directly instead of looking up anything in the data fork.
> > */
> > if (xfs_is_reflink_inode(ip) &&
> > - xfs_iext_lookup_extent(ip, ip->i_cowfp, offset_fsb, &icur, imap) &&
> > - imap->br_startoff <= offset_fsb) {
> > + xfs_iext_lookup_extent(ip, ip->i_cowfp, offset_fsb, &icur, imap)) {
> > + cow_fsb = imap->br_startoff;
> > + cow_valid = true;
> > + }
> > + if (cow_valid && cow_fsb <= offset_fsb) {
> > xfs_iunlock(ip, XFS_ILOCK_SHARED);
> > /*
> > * Truncate can race with writeback since writeback doesn't
> > @@ -430,6 +434,10 @@ xfs_map_blocks(
> >
> > error = xfs_bmapi_read(ip, offset_fsb, end_fsb - offset_fsb,
> > imap, &nimaps, XFS_BMAPI_ENTIRE);
> > + xfs_iunlock(ip, XFS_ILOCK_SHARED);
> > + if (error)
> > + return error;
> > +
> > if (!nimaps) {
> > /*
> > * Lookup returns no match? Beyond eof? regardless,
> > @@ -451,16 +459,17 @@ xfs_map_blocks(
> > * is a pending CoW reservation before the end of this extent,
> > * so that we pick up the COW extents in the next iteration.
> > */
> > - xfs_reflink_trim_irec_to_next_cow(ip, offset_fsb, imap);
> > + if (cow_valid &&
> > + cow_fsb < imap->br_startoff + imap->br_blockcount) {
> > + imap->br_blockcount = cow_fsb - imap->br_startoff;
> > + trace_xfs_reflink_trim_irec(ip, imap);
> > + }
> > +
> > if (imap->br_state == XFS_EXT_UNWRITTEN)
> > *type = XFS_IO_UNWRITTEN;
> > else
> > *type = XFS_IO_OVERWRITE;
> > }
> > - xfs_iunlock(ip, XFS_ILOCK_SHARED);
> > - if (error)
> > - return error;
> > -
> > done:
> > switch (*type) {
> > case XFS_IO_HOLE:
> > diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c
> > index 8e5eb8e70c89..ff76bc56ff3d 100644
> > --- a/fs/xfs/xfs_reflink.c
> > +++ b/fs/xfs/xfs_reflink.c
> > @@ -484,39 +484,6 @@ xfs_reflink_allocate_cow(
> > return error;
> > }
> >
> > -/*
> > - * Trim an extent to end at the next CoW reservation past offset_fsb.
> > - */
> > -void
> > -xfs_reflink_trim_irec_to_next_cow(
> > - struct xfs_inode *ip,
> > - xfs_fileoff_t offset_fsb,
> > - struct xfs_bmbt_irec *imap)
> > -{
> > - struct xfs_ifork *ifp = XFS_IFORK_PTR(ip, XFS_COW_FORK);
> > - struct xfs_bmbt_irec got;
> > - struct xfs_iext_cursor icur;
> > -
> > - if (!xfs_is_reflink_inode(ip))
> > - return;
> > -
> > - /* Find the extent in the CoW fork. */
> > - if (!xfs_iext_lookup_extent(ip, ifp, offset_fsb, &icur, &got))
> > - return;
> > -
> > - /* This is the extent before; try sliding up one. */
> > - if (got.br_startoff < offset_fsb) {
> > - if (!xfs_iext_next_extent(ifp, &icur, &got))
> > - return;
> > - }
> > -
> > - if (got.br_startoff >= imap->br_startoff + imap->br_blockcount)
> > - return;
> > -
> > - imap->br_blockcount = got.br_startoff - imap->br_startoff;
> > - trace_xfs_reflink_trim_irec(ip, imap);
> > -}
> > -
> > /*
> > * Cancel CoW reservations for some block range of an inode.
> > *
> > diff --git a/fs/xfs/xfs_reflink.h b/fs/xfs/xfs_reflink.h
> > index 15a456492667..e8d4d50c629f 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 void xfs_reflink_trim_irec_to_next_cow(struct xfs_inode *ip,
> > - xfs_fileoff_t offset_fsb, struct xfs_bmbt_irec *imap);
> >
> > extern int xfs_reflink_cancel_cow_blocks(struct xfs_inode *ip,
> > struct xfs_trans **tpp, xfs_fileoff_t offset_fsb,
> > --
> > 2.17.0
> >
> > --
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