Implement swapext for filesystems that have reverse mapping. Back in
the reflink patches, we augmented the bmap code with a 'REMAP' flag
that updates only the bmbt and doesn't touch the allocator and
implemented log redo items for those two operations. Now we can
rewrite extent swapping as a (looong) series of remap operations.
This is far less efficient than the fork swapping method implemented
in the past, so we only switch this on for rmap.
Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
---
fs/xfs/xfs_bmap_util.c | 164 +++++++++++++++++++++++++++++++++++++++++++++++-
fs/xfs/xfs_trace.h | 5 +
2 files changed, 166 insertions(+), 3 deletions(-)
diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c
index 3bd85aa..e9b48dc 100644
--- a/fs/xfs/xfs_bmap_util.c
+++ b/fs/xfs/xfs_bmap_util.c
@@ -1559,6 +1559,13 @@ xfs_swap_extents_check_format(
return -EINVAL;
/*
+ * If we have to use the (expensive) rmap swap method, we can
+ * handle any number of extents and any format.
+ */
+ if (xfs_sb_version_hasrmapbt(&ip->i_mount->m_sb))
+ return 0;
+
+ /*
* if the target inode is in extent form and the temp inode is in btree
* form then we will end up with the target inode in the wrong format
* as we already know there are less extents in the temp inode.
@@ -1627,6 +1634,132 @@ 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_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;
+ xfs_fsblock_t firstfsb;
+ struct xfs_defer_ops dfops;
+ int done;
+ 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_d.di_flags2;
+ if (ip->i_d.di_flags2 & XFS_DIFLAG2_REFLINK)
+ tip->i_d.di_flags2 |= 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. */
+ done = false;
+ while (tirec.br_blockcount) {
+ xfs_defer_init(&dfops, &firstfsb);
+ 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_defer;
+ 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);
+
+ /* Remove the mapping from the donor file. */
+ error = xfs_bmap_unmap_extent((*tpp)->t_mountp, &dfops,
+ tip, XFS_DATA_FORK, &uirec);
+ if (error)
+ goto out_defer;
+
+ /* Remove the mapping from the source file. */
+ error = xfs_bmap_unmap_extent((*tpp)->t_mountp, &dfops,
+ ip, XFS_DATA_FORK, &irec);
+ if (error)
+ goto out_defer;
+
+ /* Map the donor file's blocks into the source file. */
+ error = xfs_bmap_map_extent((*tpp)->t_mountp, &dfops,
+ ip, XFS_DATA_FORK, &uirec);
+ if (error)
+ goto out_defer;
+
+ /* Map the source file's blocks into the donor file. */
+ error = xfs_bmap_map_extent((*tpp)->t_mountp, &dfops,
+ tip, XFS_DATA_FORK, &irec);
+ if (error)
+ goto out_defer;
+
+ error = xfs_defer_finish(tpp, &dfops, ip);
+ if (error)
+ goto out_defer;
+
+ 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_d.di_flags2 = tip_flags2;
+ return 0;
+
+out_defer:
+ xfs_defer_cancel(&dfops);
+out:
+ trace_xfs_swap_extent_rmap_error(ip, error, _RET_IP_);
+ tip->i_d.di_flags2 = tip_flags2;
+ return error;
+}
+
/* Swap the extents of two files by swapping data forks. */
STATIC int
xfs_swap_extent_forks(
@@ -1777,6 +1910,7 @@ xfs_swap_extents(
int lock_flags;
struct xfs_ifork *cowfp;
__uint64_t f;
+ int resblks;
/*
* Lock the inodes against other IO, page faults and truncate to
@@ -1807,7 +1941,28 @@ xfs_swap_extents(
if (error)
goto out_unlock;
- error = xfs_trans_alloc(mp, &M_RES(mp)->tr_ichange, 0, 0, 0, &tp);
+ /*
+ * Extent "swapping" with rmap requires a permanent reservation and
+ * a block reservation because it's really just a remap operation
+ * performed with log redo items!
+ */
+ if (xfs_sb_version_hasrmapbt(&mp->m_sb)) {
+ /*
+ * Conceptually this shouldn't affect the shape of either
+ * bmbt, but since we atomically move extents one by one,
+ * we reserve enough space to rebuild both trees.
+ */
+ resblks = XFS_NEXTENTADD_SPACE_RES(mp,
+ XFS_IFORK_NEXTENTS(ip, XFS_DATA_FORK),
+ XFS_DATA_FORK) +
+ XFS_NEXTENTADD_SPACE_RES(mp,
+ XFS_IFORK_NEXTENTS(tip, XFS_DATA_FORK),
+ XFS_DATA_FORK);
+ error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write, resblks,
+ 0, 0, &tp);
+ } else
+ error = xfs_trans_alloc(mp, &M_RES(mp)->tr_ichange, 0,
+ 0, 0, &tp);
if (error)
goto out_unlock;
@@ -1866,8 +2021,11 @@ xfs_swap_extents(
src_log_flags = XFS_ILOG_CORE;
target_log_flags = XFS_ILOG_CORE;
- error = xfs_swap_extent_forks(tp, ip, tip, &src_log_flags,
- &target_log_flags);
+ if (xfs_sb_version_hasrmapbt(&mp->m_sb))
+ error = xfs_swap_extent_rmap(&tp, ip, tip);
+ else
+ error = xfs_swap_extent_forks(tp, ip, tip, &src_log_flags,
+ &target_log_flags);
if (error)
goto out_trans_cancel;
diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h
index 8b1f803..f980cca 100644
--- a/fs/xfs/xfs_trace.h
+++ b/fs/xfs/xfs_trace.h
@@ -3345,6 +3345,11 @@ DEFINE_INODE_EVENT(xfs_reflink_cancel_pending_cow);
DEFINE_INODE_IREC_EVENT(xfs_reflink_cancel_cow);
DEFINE_INODE_ERROR_EVENT(xfs_reflink_cancel_pending_cow_error);
+/* 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);
+
#endif /* _TRACE_XFS_H */
#undef TRACE_INCLUDE_PATH
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