On Thu, Jun 28, 2018 at 12:36:25PM -0400, Brian Foster wrote:
> Use ->t_dfops for all remaining xfs_bunmapi() callers. This prepares
> the latter to no longer require a dfops parameter.
>
> Note that xfs_itruncate_extents_flags() associates a local dfops
> with a transaction provided from the caller. Since there are
> multiple callers, set and reset ->t_dfops before the function
> returns to avoid exposure of stack memory to the caller.
>
> Signed-off-by: Brian Foster <bfoster@xxxxxxxxxx>
> ---
> fs/xfs/xfs_bmap_util.c | 9 +++++----
> fs/xfs/xfs_inode.c | 12 ++++++++----
> fs/xfs/xfs_reflink.c | 27 +++++++++++++++------------
> fs/xfs/xfs_symlink.c | 9 +++++----
> 4 files changed, 33 insertions(+), 24 deletions(-)
>
> diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c
> index c40cb711447f..78189cf385f2 100644
> --- a/fs/xfs/xfs_bmap_util.c
> +++ b/fs/xfs/xfs_bmap_util.c
> @@ -1043,13 +1043,14 @@ xfs_unmap_extent(
> xfs_trans_ijoin(tp, ip, 0);
>
> xfs_defer_init(&dfops, &firstfsb);
> + tp->t_dfops = &dfops;
> error = xfs_bunmapi(tp, ip, startoffset_fsb, len_fsb, 0, 2, &firstfsb,
> - &dfops, done);
> + tp->t_dfops, done);
> if (error)
> goto out_bmap_cancel;
>
> - xfs_defer_ijoin(&dfops, ip);
> - error = xfs_defer_finish(&tp, &dfops);
> + xfs_defer_ijoin(tp->t_dfops, ip);
> + error = xfs_defer_finish(&tp, tp->t_dfops);
> if (error)
> goto out_bmap_cancel;
>
> @@ -1059,7 +1060,7 @@ xfs_unmap_extent(
> return error;
>
> out_bmap_cancel:
> - xfs_defer_cancel(&dfops);
> + xfs_defer_cancel(tp->t_dfops);
> out_trans_cancel:
> xfs_trans_cancel(tp);
> goto out_unlock;
> diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
> index e1bc686b70b4..539d96201666 100644
> --- a/fs/xfs/xfs_inode.c
> +++ b/fs/xfs/xfs_inode.c
> @@ -1545,6 +1545,7 @@ xfs_itruncate_extents_flags(
> {
> struct xfs_mount *mp = ip->i_mount;
> struct xfs_trans *tp = *tpp;
> + struct xfs_defer_ops *odfops = tp->t_dfops;
old_dfops?
> struct xfs_defer_ops dfops;
> xfs_fsblock_t first_block;
> xfs_fileoff_t first_unmap_block;
> @@ -1584,9 +1585,10 @@ xfs_itruncate_extents_flags(
> unmap_len = last_block - first_unmap_block + 1;
> while (!done) {
> xfs_defer_init(&dfops, &first_block);
> + tp->t_dfops = &dfops;
Why can't we attach the dfops generated by the bunmapi call onto the
original t_dfops? I guess it's so that we can drop the defer_ijoin from
dfops? It seems odd to be nesting the dfops, since we're no longer
completing them in order of oldest to newest.
--D
> error = xfs_bunmapi(tp, ip, first_unmap_block, unmap_len, flags,
> XFS_ITRUNC_MAX_EXTENTS, &first_block,
> - &dfops, &done);
> + tp->t_dfops, &done);
> if (error)
> goto out_bmap_cancel;
>
> @@ -1594,8 +1596,8 @@ xfs_itruncate_extents_flags(
> * Duplicate the transaction that has the permanent
> * reservation and commit the old transaction.
> */
> - xfs_defer_ijoin(&dfops, ip);
> - error = xfs_defer_finish(&tp, &dfops);
> + xfs_defer_ijoin(tp->t_dfops, ip);
> + error = xfs_defer_finish(&tp, tp->t_dfops);
> if (error)
> goto out_bmap_cancel;
>
> @@ -1623,6 +1625,8 @@ xfs_itruncate_extents_flags(
> trace_xfs_itruncate_extents_end(ip, new_size);
>
> out:
> + /* ->t_dfops points to local stack, don't leak it! */
> + tp->t_dfops = odfops;
> *tpp = tp;
> return error;
> out_bmap_cancel:
> @@ -1631,7 +1635,7 @@ xfs_itruncate_extents_flags(
> * the transaction can be properly aborted. We just need to make sure
> * we're not holding any resources that we were not when we came in.
> */
> - xfs_defer_cancel(&dfops);
> + xfs_defer_cancel(tp->t_dfops);
> goto out;
> }
>
> diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c
> index 3b2b8f5851c0..bb22a17fbca8 100644
> --- a/fs/xfs/xfs_reflink.c
> +++ b/fs/xfs/xfs_reflink.c
> @@ -763,9 +763,10 @@ xfs_reflink_end_cow(
>
> /* Unmap the old blocks in the data fork. */
> xfs_defer_init(&dfops, &firstfsb);
> + tp->t_dfops = &dfops;
> rlen = del.br_blockcount;
> error = __xfs_bunmapi(tp, ip, del.br_startoff, &rlen, 0, 1,
> - &firstfsb, &dfops);
> + &firstfsb, tp->t_dfops);
> if (error)
> goto out_defer;
>
> @@ -777,13 +778,14 @@ xfs_reflink_end_cow(
> trace_xfs_reflink_cow_remap(ip, &del);
>
> /* Free the CoW orphan record. */
> - error = xfs_refcount_free_cow_extent(tp->t_mountp, &dfops,
> + error = xfs_refcount_free_cow_extent(tp->t_mountp, tp->t_dfops,
> del.br_startblock, del.br_blockcount);
> if (error)
> goto out_defer;
>
> /* Map the new blocks into the data fork. */
> - error = xfs_bmap_map_extent(tp->t_mountp, &dfops, ip, &del);
> + error = xfs_bmap_map_extent(tp->t_mountp, tp->t_dfops, ip,
> + &del);
> if (error)
> goto out_defer;
>
> @@ -794,8 +796,8 @@ xfs_reflink_end_cow(
> /* Remove the mapping from the CoW fork. */
> xfs_bmap_del_extent_cow(ip, &icur, &got, &del);
>
> - xfs_defer_ijoin(&dfops, ip);
> - error = xfs_defer_finish(&tp, &dfops);
> + xfs_defer_ijoin(tp->t_dfops, ip);
> + error = xfs_defer_finish(&tp, tp->t_dfops);
> if (error)
> goto out_defer;
> if (!xfs_iext_get_extent(ifp, &icur, &got))
> @@ -813,7 +815,7 @@ xfs_reflink_end_cow(
> return 0;
>
> out_defer:
> - xfs_defer_cancel(&dfops);
> + xfs_defer_cancel(tp->t_dfops);
> out_cancel:
> xfs_trans_cancel(tp);
> xfs_iunlock(ip, XFS_ILOCK_EXCL);
> @@ -1112,8 +1114,9 @@ xfs_reflink_remap_extent(
> rlen = unmap_len;
> while (rlen) {
> xfs_defer_init(&dfops, &firstfsb);
> + tp->t_dfops = &dfops;
> error = __xfs_bunmapi(tp, ip, destoff, &rlen, 0, 1,
> - &firstfsb, &dfops);
> + &firstfsb, tp->t_dfops);
> if (error)
> goto out_defer;
>
> @@ -1134,12 +1137,12 @@ xfs_reflink_remap_extent(
> uirec.br_blockcount, uirec.br_startblock);
>
> /* Update the refcount tree */
> - error = xfs_refcount_increase_extent(mp, &dfops, &uirec);
> + error = xfs_refcount_increase_extent(mp, tp->t_dfops, &uirec);
> if (error)
> goto out_defer;
>
> /* Map the new blocks into the data fork. */
> - error = xfs_bmap_map_extent(mp, &dfops, ip, &uirec);
> + error = xfs_bmap_map_extent(mp, tp->t_dfops, ip, &uirec);
> if (error)
> goto out_defer;
>
> @@ -1160,8 +1163,8 @@ xfs_reflink_remap_extent(
>
> next_extent:
> /* Process all the deferred stuff. */
> - xfs_defer_ijoin(&dfops, ip);
> - error = xfs_defer_finish(&tp, &dfops);
> + xfs_defer_ijoin(tp->t_dfops, ip);
> + error = xfs_defer_finish(&tp, tp->t_dfops);
> if (error)
> goto out_defer;
> }
> @@ -1173,7 +1176,7 @@ xfs_reflink_remap_extent(
> return 0;
>
> out_defer:
> - xfs_defer_cancel(&dfops);
> + xfs_defer_cancel(tp->t_dfops);
> out_cancel:
> xfs_trans_cancel(tp);
> xfs_iunlock(ip, XFS_ILOCK_EXCL);
> diff --git a/fs/xfs/xfs_symlink.c b/fs/xfs/xfs_symlink.c
> index 2b6bcfd39c14..290ae13d4673 100644
> --- a/fs/xfs/xfs_symlink.c
> +++ b/fs/xfs/xfs_symlink.c
> @@ -444,6 +444,7 @@ xfs_inactive_symlink_rmt(
> */
> done = 0;
> xfs_defer_init(&dfops, &first_block);
> + tp->t_dfops = &dfops;
> nmaps = ARRAY_SIZE(mval);
> error = xfs_bmapi_read(ip, 0, xfs_symlink_blocks(mp, size),
> mval, &nmaps, 0);
> @@ -466,15 +467,15 @@ xfs_inactive_symlink_rmt(
> * Unmap the dead block(s) to the dfops.
> */
> error = xfs_bunmapi(tp, ip, 0, size, 0, nmaps,
> - &first_block, &dfops, &done);
> + &first_block, tp->t_dfops, &done);
> if (error)
> goto error_bmap_cancel;
> ASSERT(done);
> /*
> * Commit the first transaction. This logs the EFI and the inode.
> */
> - xfs_defer_ijoin(&dfops, ip);
> - error = xfs_defer_finish(&tp, &dfops);
> + xfs_defer_ijoin(tp->t_dfops, ip);
> + error = xfs_defer_finish(&tp, tp->t_dfops);
> if (error)
> goto error_bmap_cancel;
>
> @@ -499,7 +500,7 @@ xfs_inactive_symlink_rmt(
> return 0;
>
> error_bmap_cancel:
> - xfs_defer_cancel(&dfops);
> + xfs_defer_cancel(tp->t_dfops);
> error_trans_cancel:
> xfs_trans_cancel(tp);
> error_unlock:
> --
> 2.17.1
>
> --
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