[PATCH 15/25] xfs: port xfs_swap_extents_rmap to our new code

Darrick J. Wong
2023-12-31T20:28:09Z

The inner loop of xfs_swap_extents_rmap does the same work as
xfs_swapext_finish_one, so adapt it to use that. Doing so has the side
benefit that the older code path no longer wastes its time remapping
shared extents.

This forms the basis of the non-atomic swaprange implementation.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
---
fs/xfs/xfs_bmap_util.c | 151 +++++-------------------------------------------
fs/xfs/xfs_trace.h | 5 --
2 files changed, 16 insertions(+), 140 deletions(-)

diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c
index 87ac9777c1eaf..8ca681d78bbcb 100644
--- a/fs/xfs/xfs_bmap_util.c
+++ b/fs/xfs/xfs_bmap_util.c
@@ -1354,138 +1354,6 @@ xfs_swap_extent_flush(
return 0;
}

-/*
- * Move extents from one file to another, when rmap is enabled.
- */
-STATIC int
-xfs_swap_extent_rmap(
- struct xfs_trans **tpp,
- struct xfs_inode *ip,
- struct xfs_inode *tip)
-{
- struct xfs_trans *tp = *tpp;
- struct xfs_bmbt_irec irec;
- struct xfs_bmbt_irec uirec;
- struct xfs_bmbt_irec tirec;
- xfs_fileoff_t offset_fsb;
- xfs_fileoff_t end_fsb;
- xfs_filblks_t count_fsb;
- int error;
- xfs_filblks_t ilen;
- xfs_filblks_t rlen;
- int nimaps;
- uint64_t tip_flags2;
-
- /*
- * If the source file has shared blocks, we must flag the donor
- * file as having shared blocks so that we get the shared-block
- * rmap functions when we go to fix up the rmaps. The flags
- * will be switch for reals later.
- */
- tip_flags2 = tip->i_diflags2;
- if (ip->i_diflags2 & XFS_DIFLAG2_REFLINK)
- tip->i_diflags2 |= XFS_DIFLAG2_REFLINK;
-
- offset_fsb = 0;
- end_fsb = XFS_B_TO_FSB(ip->i_mount, i_size_read(VFS_I(ip)));
- count_fsb = (xfs_filblks_t)(end_fsb - offset_fsb);
-
- while (count_fsb) {
- /* Read extent from the donor file */
- nimaps = 1;
- error = xfs_bmapi_read(tip, offset_fsb, count_fsb, &tirec,
- &nimaps, 0);
- if (error)
- goto out;
- ASSERT(nimaps == 1);
- ASSERT(tirec.br_startblock != DELAYSTARTBLOCK);
-
- trace_xfs_swap_extent_rmap_remap(tip, &tirec);
- ilen = tirec.br_blockcount;
-
- /* Unmap the old blocks in the source file. */
- while (tirec.br_blockcount) {
- ASSERT(tp->t_highest_agno == NULLAGNUMBER);
- trace_xfs_swap_extent_rmap_remap_piece(tip, &tirec);
-
- /* Read extent from the source file */
- nimaps = 1;
- error = xfs_bmapi_read(ip, tirec.br_startoff,
- tirec.br_blockcount, &irec,
- &nimaps, 0);
- if (error)
- goto out;
- ASSERT(nimaps == 1);
- ASSERT(tirec.br_startoff == irec.br_startoff);
- trace_xfs_swap_extent_rmap_remap_piece(ip, &irec);
-
- /* Trim the extent. */
- uirec = tirec;
- uirec.br_blockcount = rlen = min_t(xfs_filblks_t,
- tirec.br_blockcount,
- irec.br_blockcount);
- trace_xfs_swap_extent_rmap_remap_piece(tip, &uirec);
-
- if (xfs_bmap_is_real_extent(&uirec)) {
- error = xfs_iext_count_may_overflow(ip,
- XFS_DATA_FORK,
- XFS_IEXT_SWAP_RMAP_CNT);
- if (error == -EFBIG)
- error = xfs_iext_count_upgrade(tp, ip,
- XFS_IEXT_SWAP_RMAP_CNT);
- if (error)
- goto out;
- }
-
- if (xfs_bmap_is_real_extent(&irec)) {
- error = xfs_iext_count_may_overflow(tip,
- XFS_DATA_FORK,
- XFS_IEXT_SWAP_RMAP_CNT);
- if (error == -EFBIG)
- error = xfs_iext_count_upgrade(tp, ip,
- XFS_IEXT_SWAP_RMAP_CNT);
- if (error)
- goto out;
- }
-
- /* Remove the mapping from the donor file. */
- xfs_bmap_unmap_extent(tp, tip, XFS_DATA_FORK, &uirec);
-
- /* Remove the mapping from the source file. */
- xfs_bmap_unmap_extent(tp, ip, XFS_DATA_FORK, &irec);
-
- /* Map the donor file's blocks into the source file. */
- xfs_bmap_map_extent(tp, ip, XFS_DATA_FORK, &uirec);
-
- /* Map the source file's blocks into the donor file. */
- xfs_bmap_map_extent(tp, tip, XFS_DATA_FORK, &irec);
-
- error = xfs_defer_finish(tpp);
- tp = *tpp;
- if (error)
- goto out;
-
- tirec.br_startoff += rlen;
- if (tirec.br_startblock != HOLESTARTBLOCK &&
- tirec.br_startblock != DELAYSTARTBLOCK)
- tirec.br_startblock += rlen;
- tirec.br_blockcount -= rlen;
- }
-
- /* Roll on... */
- count_fsb -= ilen;
- offset_fsb += ilen;
- }
-
- tip->i_diflags2 = tip_flags2;
- return 0;
-
-out:
- trace_xfs_swap_extent_rmap_error(ip, error, _RET_IP_);
- tip->i_diflags2 = tip_flags2;
- return error;
-}
-
/* Swap the extents of two files by swapping data forks. */
STATIC int
xfs_swap_extent_forks(
@@ -1772,13 +1640,24 @@ xfs_swap_extents(
src_log_flags = XFS_ILOG_CORE;
target_log_flags = XFS_ILOG_CORE;

- if (xfs_has_rmapbt(mp))
- error = xfs_swap_extent_rmap(&tp, ip, tip);
- else
+ if (xfs_has_rmapbt(mp)) {
+ struct xfs_swapext_req req = {
+ .ip1 = tip,
+ .ip2 = ip,
+ .whichfork = XFS_DATA_FORK,
+ .blockcount = XFS_B_TO_FSB(ip->i_mount,
+ i_size_read(VFS_I(ip))),
+ };
+
+ xfs_swapext(tp, &req);
+ error = xfs_defer_finish(&tp);
+ } else
error = xfs_swap_extent_forks(tp, ip, tip, &src_log_flags,
&target_log_flags);
- if (error)
+ if (error) {
+ trace_xfs_swap_extent_error(ip, error, _THIS_IP_);
goto out_trans_cancel;
+ }

/* Do we have to swap reflink flags? */
if ((ip->i_diflags2 & XFS_DIFLAG2_REFLINK) ^
diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h
index 53a6122d307ff..47c30d8093289 100644
--- a/fs/xfs/xfs_trace.h
+++ b/fs/xfs/xfs_trace.h
@@ -3746,13 +3746,10 @@ DEFINE_INODE_ERROR_EVENT(xfs_reflink_end_cow_error);

DEFINE_INODE_IREC_EVENT(xfs_reflink_cancel_cow);

-/* rmap swapext tracepoints */
-DEFINE_INODE_IREC_EVENT(xfs_swap_extent_rmap_remap);
-DEFINE_INODE_IREC_EVENT(xfs_swap_extent_rmap_remap_piece);
-DEFINE_INODE_ERROR_EVENT(xfs_swap_extent_rmap_error);

/* swapext tracepoints */
DEFINE_INODE_ERROR_EVENT(xfs_file_xchg_range_error);
+DEFINE_INODE_ERROR_EVENT(xfs_swap_extent_error);
DEFINE_INODE_IREC_EVENT(xfs_swapext_extent1_skip);
DEFINE_INODE_IREC_EVENT(xfs_swapext_extent1);
DEFINE_INODE_IREC_EVENT(xfs_swapext_extent2);