On Tue, Jun 06, 2017 at 12:28:33PM -0400, Brian Foster wrote:
> On Fri, Jun 02, 2017 at 02:24:55PM -0700, Darrick J. Wong wrote:
> > From: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
> >
> > Separate the "clear reflink flag" function into one function that checks
> > if the flag is needed, and a second function that checks and clears the
> > flag. The inode scrub code will want to check the necessity of the flag
> > without clearing it.
> >
> > Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
> > ---
> > fs/xfs/xfs_reflink.c | 88 ++++++++++++++++++++++++++++++--------------------
> > fs/xfs/xfs_reflink.h | 2 +
> > 2 files changed, 54 insertions(+), 36 deletions(-)
> >
> >
> > diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c
> > index e25c995..133ee02 100644
> > --- a/fs/xfs/xfs_reflink.c
> > +++ b/fs/xfs/xfs_reflink.c
> > @@ -1406,57 +1406,73 @@ xfs_reflink_dirty_extents(
> > return error;
> > }
> >
> > -/* Clear the inode reflink flag if there are no shared extents. */
> > +/* Does this inode need the reflink flag? */
> > int
> > -xfs_reflink_clear_inode_flag(
> > - struct xfs_inode *ip,
> > - struct xfs_trans **tpp)
> > +xfs_reflink_needs_inode_flag(
> > + struct xfs_trans *tp,
> > + struct xfs_inode *ip,
> > + bool *needs_flag)
>
> This looks Ok to me, but just a nit that the _needs_inode_flag() name
> sounds slightly confusing to me because any context around the flag is
> now isolated to the caller. Could we call this something more generic
> like _has_shared_extents() (and rename needs_flag appropriately as
> well)?
Yes, that's a much better name. :)
int xfs_reflink_inode_has_shared_extents(..., bool *has_shared);
--D
>
> Brian
>
> > {
> > - struct xfs_mount *mp = ip->i_mount;
> > - xfs_fileoff_t fbno;
> > - xfs_filblks_t end;
> > - xfs_agnumber_t agno;
> > - xfs_agblock_t agbno;
> > - xfs_extlen_t aglen;
> > - xfs_agblock_t rbno;
> > - xfs_extlen_t rlen;
> > - struct xfs_bmbt_irec map;
> > - int nmaps;
> > - int error = 0;
> > -
> > - ASSERT(xfs_is_reflink_inode(ip));
> > + struct xfs_bmbt_irec got;
> > + struct xfs_mount *mp = ip->i_mount;
> > + struct xfs_ifork *ifp;
> > + xfs_agnumber_t agno;
> > + xfs_agblock_t agbno;
> > + xfs_extlen_t aglen;
> > + xfs_agblock_t rbno;
> > + xfs_extlen_t rlen;
> > + xfs_extnum_t idx;
> > + bool found;
> > + int error;
> >
> > - fbno = 0;
> > - end = XFS_B_TO_FSB(mp, i_size_read(VFS_I(ip)));
> > - while (end - fbno > 0) {
> > - nmaps = 1;
> > - /*
> > - * Look for extents in the file. Skip holes, delalloc, or
> > - * unwritten extents; they can't be reflinked.
> > - */
> > - error = xfs_bmapi_read(ip, fbno, end - fbno, &map, &nmaps, 0);
> > + ifp = XFS_IFORK_PTR(ip, XFS_DATA_FORK);
> > + if (!(ifp->if_flags & XFS_IFEXTENTS)) {
> > + error = xfs_iread_extents(tp, ip, XFS_DATA_FORK);
> > if (error)
> > return error;
> > - if (nmaps == 0)
> > - break;
> > - if (!xfs_bmap_is_real_extent(&map))
> > - goto next;
> > + }
> >
> > - agno = XFS_FSB_TO_AGNO(mp, map.br_startblock);
> > - agbno = XFS_FSB_TO_AGBNO(mp, map.br_startblock);
> > - aglen = map.br_blockcount;
> > + *needs_flag = false;
> > + found = xfs_iext_lookup_extent(ip, ifp, 0, &idx, &got);
> > + while (found) {
> > + if (isnullstartblock(got.br_startblock) ||
> > + got.br_state != XFS_EXT_NORM)
> > + goto next;
> > + agno = XFS_FSB_TO_AGNO(mp, got.br_startblock);
> > + agbno = XFS_FSB_TO_AGBNO(mp, got.br_startblock);
> > + aglen = got.br_blockcount;
> >
> > - error = xfs_reflink_find_shared(mp, *tpp, agno, agbno, aglen,
> > + error = xfs_reflink_find_shared(mp, tp, agno, agbno, aglen,
> > &rbno, &rlen, false);
> > if (error)
> > return error;
> > /* Is there still a shared block here? */
> > - if (rbno != NULLAGBLOCK)
> > + if (rbno != NULLAGBLOCK) {
> > + *needs_flag = true;
> > return 0;
> > + }
> > next:
> > - fbno = map.br_startoff + map.br_blockcount;
> > + found = xfs_iext_get_extent(ifp, ++idx, &got);
> > }
> >
> > + return 0;
> > +}
> > +
> > +/* Clear the inode reflink flag if there are no shared extents. */
> > +int
> > +xfs_reflink_clear_inode_flag(
> > + struct xfs_inode *ip,
> > + struct xfs_trans **tpp)
> > +{
> > + bool needs;
> > + int error = 0;
> > +
> > + ASSERT(xfs_is_reflink_inode(ip));
> > +
> > + error = xfs_reflink_needs_inode_flag(*tpp, ip, &needs);
> > + if (error || needs)
> > + return error;
> > +
> > /*
> > * We didn't find any shared blocks so turn off the reflink flag.
> > * First, get rid of any leftover CoW mappings.
> > diff --git a/fs/xfs/xfs_reflink.h b/fs/xfs/xfs_reflink.h
> > index b8cc5c3..a26d795 100644
> > --- a/fs/xfs/xfs_reflink.h
> > +++ b/fs/xfs/xfs_reflink.h
> > @@ -47,6 +47,8 @@ extern int xfs_reflink_end_cow(struct xfs_inode *ip, xfs_off_t offset,
> > extern int xfs_reflink_recover_cow(struct xfs_mount *mp);
> > extern int xfs_reflink_remap_range(struct file *file_in, loff_t pos_in,
> > struct file *file_out, loff_t pos_out, u64 len, bool is_dedupe);
> > +extern int xfs_reflink_needs_inode_flag(struct xfs_trans *tp,
> > + struct xfs_inode *ip, bool *needs_flag);
> > extern int xfs_reflink_clear_inode_flag(struct xfs_inode *ip,
> > struct xfs_trans **tpp);
> > extern int xfs_reflink_unshare(struct xfs_inode *ip, xfs_off_t offset,
> >
> > --
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