On Fri, Oct 05, 2018 at 03:28:09PM +1000, Dave Chinner wrote:
> On Thu, Oct 04, 2018 at 05:44:47PM -0700, Darrick J. Wong wrote:
> > From: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
> >
> > Refactor all the reflink preparation steps into a separate helper that
> > we'll use to land all the upcoming fixes for insufficient input checks.
>
> If I've read the patch right, this also changes the location of the
> page cache truncation, right? i.e. it now happens in the
> xfs_reflink_remap_prep() function instead of after the remap? I
> think the commit message needs to mention that because it's a fix to
> incorrect behaviour....
Right. Sorry I forgot to put that in the changelog.
> I've added:
>
> --
> This rework also moves the invalidation of the destination range to
> the prep function so that it is done before the range is remapped.
> This ensures that nobody can access the data in range being remapped
> until the remap is complete.
> --
>
> Sound OK?
Yep.
--D
> Otherwise this looks fine.
>
> Reviewed-by: Dave Chinner <dchinner@xxxxxxxxxx>
>
> -Dave.
>
> >
> > Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
> > ---
> > fs/xfs/xfs_reflink.c | 96 +++++++++++++++++++++++++++++++++++++-------------
> > 1 file changed, 71 insertions(+), 25 deletions(-)
> >
> >
> > diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c
> > index 38f405415b88..80ca9b6793cd 100644
> > --- a/fs/xfs/xfs_reflink.c
> > +++ b/fs/xfs/xfs_reflink.c
> > @@ -1195,11 +1195,33 @@ xfs_iolock_two_inodes_and_break_layout(
> > return 0;
> > }
> >
> > +/* Unlock both inodes after they've been prepped for a range clone. */
> > +STATIC void
> > +xfs_reflink_remap_unlock(
> > + struct file *file_in,
> > + struct file *file_out)
> > +{
> > + struct inode *inode_in = file_inode(file_in);
> > + struct xfs_inode *src = XFS_I(inode_in);
> > + struct inode *inode_out = file_inode(file_out);
> > + struct xfs_inode *dest = XFS_I(inode_out);
> > + bool same_inode = (inode_in == inode_out);
> > +
> > + xfs_iunlock(dest, XFS_MMAPLOCK_EXCL);
> > + if (!same_inode)
> > + xfs_iunlock(src, XFS_MMAPLOCK_SHARED);
> > + inode_unlock(inode_out);
> > + if (!same_inode)
> > + inode_unlock_shared(inode_in);
> > +}
> > +
> > /*
> > - * Link a range of blocks from one file to another.
> > + * Prepare two files for range cloning. Upon a successful return both inodes
> > + * will have the iolock and mmaplock held, the page cache of the out file
> > + * will be truncated, and any leases on the out file will have been broken.
> > */
> > -int
> > -xfs_reflink_remap_range(
> > +STATIC int
> > +xfs_reflink_remap_prep(
> > struct file *file_in,
> > loff_t pos_in,
> > struct file *file_out,
> > @@ -1211,19 +1233,9 @@ xfs_reflink_remap_range(
> > struct xfs_inode *src = XFS_I(inode_in);
> > struct inode *inode_out = file_inode(file_out);
> > struct xfs_inode *dest = XFS_I(inode_out);
> > - struct xfs_mount *mp = src->i_mount;
> > bool same_inode = (inode_in == inode_out);
> > - xfs_fileoff_t sfsbno, dfsbno;
> > - xfs_filblks_t fsblen;
> > - xfs_extlen_t cowextsize;
> > ssize_t ret;
> >
> > - if (!xfs_sb_version_hasreflink(&mp->m_sb))
> > - return -EOPNOTSUPP;
> > -
> > - if (XFS_FORCED_SHUTDOWN(mp))
> > - return -EIO;
> > -
> > /* Lock both files against IO */
> > ret = xfs_iolock_two_inodes_and_break_layout(inode_in, inode_out);
> > if (ret)
> > @@ -1254,8 +1266,6 @@ xfs_reflink_remap_range(
> > if (ret)
> > goto out_unlock;
> >
> > - trace_xfs_reflink_remap_range(src, pos_in, len, dest, pos_out);
> > -
> > /*
> > * Clear out post-eof preallocations because we don't have page cache
> > * backing the delayed allocations and they'll never get freed on
> > @@ -1272,6 +1282,51 @@ xfs_reflink_remap_range(
> > if (ret)
> > goto out_unlock;
> >
> > + /* Zap any page cache for the destination file's range. */
> > + truncate_inode_pages_range(&inode_out->i_data, pos_out,
> > + PAGE_ALIGN(pos_out + len) - 1);
> > + return 0;
> > +out_unlock:
> > + xfs_reflink_remap_unlock(file_in, file_out);
> > + return ret;
> > +}
> > +
> > +/*
> > + * Link a range of blocks from one file to another.
> > + */
> > +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)
> > +{
> > + struct inode *inode_in = file_inode(file_in);
> > + struct xfs_inode *src = XFS_I(inode_in);
> > + struct inode *inode_out = file_inode(file_out);
> > + struct xfs_inode *dest = XFS_I(inode_out);
> > + struct xfs_mount *mp = src->i_mount;
> > + xfs_fileoff_t sfsbno, dfsbno;
> > + xfs_filblks_t fsblen;
> > + xfs_extlen_t cowextsize;
> > + ssize_t ret;
> > +
> > + if (!xfs_sb_version_hasreflink(&mp->m_sb))
> > + return -EOPNOTSUPP;
> > +
> > + if (XFS_FORCED_SHUTDOWN(mp))
> > + return -EIO;
> > +
> > + /* Prepare and then clone file data. */
> > + ret = xfs_reflink_remap_prep(file_in, pos_in, file_out, pos_out,
> > + len, is_dedupe);
> > + if (ret)
> > + return ret;
> > +
> > + trace_xfs_reflink_remap_range(src, pos_in, len, dest, pos_out);
> > +
> > dfsbno = XFS_B_TO_FSBT(mp, pos_out);
> > sfsbno = XFS_B_TO_FSBT(mp, pos_in);
> > fsblen = XFS_B_TO_FSB(mp, len);
> > @@ -1280,10 +1335,6 @@ xfs_reflink_remap_range(
> > if (ret)
> > goto out_unlock;
> >
> > - /* Zap any page cache for the destination file's range. */
> > - truncate_inode_pages_range(&inode_out->i_data, pos_out,
> > - PAGE_ALIGN(pos_out + len) - 1);
> > -
> > /*
> > * Carry the cowextsize hint from src to dest if we're sharing the
> > * entire source file to the entire destination file, the source file
> > @@ -1300,12 +1351,7 @@ xfs_reflink_remap_range(
> > is_dedupe);
> >
> > out_unlock:
> > - xfs_iunlock(dest, XFS_MMAPLOCK_EXCL);
> > - if (!same_inode)
> > - xfs_iunlock(src, XFS_MMAPLOCK_SHARED);
> > - inode_unlock(inode_out);
> > - if (!same_inode)
> > - inode_unlock_shared(inode_in);
> > + xfs_reflink_remap_unlock(file_in, file_out);
> > if (ret)
> > trace_xfs_reflink_remap_range_error(dest, ret, _RET_IP_);
> > return ret;
> >
> >
>
> --
> Dave Chinner
> david@xxxxxxxxxxxxx
