1 files changed, 312 insertions, 31 deletions

diff --git a/fs/xfs/libxfs/xfs_trans_resv.c b/fs/xfs/libxfs/xfs_trans_resv.c
index 13d00c7166e1..86a111d0f2fc 100644
--- a/fs/xfs/libxfs/xfs_trans_resv.c
+++ b/fs/xfs/libxfs/xfs_trans_resv.c
@@ -22,6 +22,12 @@
 #include "xfs_rtbitmap.h"
 #include "xfs_attr_item.h"
 #include "xfs_log.h"
+#include "xfs_defer.h"
+#include "xfs_bmap_item.h"
+#include "xfs_extfree_item.h"
+#include "xfs_rmap_item.h"
+#include "xfs_refcount_item.h"
+#include "xfs_trace.h"
 
 #define _ALLOC	true
 #define _FREE	false
@@ -264,6 +270,42 @@ xfs_rtalloc_block_count(
  */
 
 /*
+ * Finishing a data device refcount updates (t1):
+ *    the agfs of the ags containing the blocks: nr_ops * sector size
+ *    the refcount btrees: nr_ops * 1 trees * (2 * max depth - 1) * block size
+ */
+inline unsigned int
+xfs_calc_finish_cui_reservation(
+	struct xfs_mount	*mp,
+	unsigned int		nr_ops)
+{
+	if (!xfs_has_reflink(mp))
+		return 0;
+
+	return xfs_calc_buf_res(nr_ops, mp->m_sb.sb_sectsize) +
+	       xfs_calc_buf_res(xfs_refcountbt_block_count(mp, nr_ops),
+			       mp->m_sb.sb_blocksize);
+}
+
+/*
+ * Realtime refcount updates (t2);
+ *    the rt refcount inode
+ *    the rtrefcount btrees: nr_ops * 1 trees * (2 * max depth - 1) * block size
+ */
+inline unsigned int
+xfs_calc_finish_rt_cui_reservation(
+	struct xfs_mount	*mp,
+	unsigned int		nr_ops)
+{
+	if (!xfs_has_rtreflink(mp))
+		return 0;
+
+	return xfs_calc_inode_res(mp, 1) +
+	       xfs_calc_buf_res(xfs_rtrefcountbt_block_count(mp, nr_ops),
+				     mp->m_sb.sb_blocksize);
+}
+
+/*
  * Compute the log reservation required to handle the refcount update
  * transaction.  Refcount updates are always done via deferred log items.
  *
@@ -280,19 +322,10 @@ xfs_calc_refcountbt_reservation(
 	struct xfs_mount	*mp,
 	unsigned int		nr_ops)
 {
-	unsigned int		blksz = XFS_FSB_TO_B(mp, 1);
-	unsigned int		t1, t2 = 0;
+	unsigned int		t1, t2;
 
-	if (!xfs_has_reflink(mp))
-		return 0;
-
-	t1 = xfs_calc_buf_res(nr_ops, mp->m_sb.sb_sectsize) +
-	     xfs_calc_buf_res(xfs_refcountbt_block_count(mp, nr_ops), blksz);
-
-	if (xfs_has_realtime(mp))
-		t2 = xfs_calc_inode_res(mp, 1) +
-		     xfs_calc_buf_res(xfs_rtrefcountbt_block_count(mp, nr_ops),
-				     blksz);
+	t1 = xfs_calc_finish_cui_reservation(mp, nr_ops);
+	t2 = xfs_calc_finish_rt_cui_reservation(mp, nr_ops);
 
 	return max(t1, t2);
 }
@@ -380,6 +413,96 @@ xfs_calc_write_reservation_minlogsize(
 }
 
 /*
+ * Finishing an EFI can free the blocks and bmap blocks (t2):
+ *    the agf for each of the ags: nr * sector size
+ *    the agfl for each of the ags: nr * sector size
+ *    the super block to reflect the freed blocks: sector size
+ *    worst case split in allocation btrees per extent assuming nr extents:
+ *		nr exts * 2 trees * (2 * max depth - 1) * block size
+ */
+inline unsigned int
+xfs_calc_finish_efi_reservation(
+	struct xfs_mount	*mp,
+	unsigned int		nr)
+{
+	return xfs_calc_buf_res((2 * nr) + 1, mp->m_sb.sb_sectsize) +
+	       xfs_calc_buf_res(xfs_allocfree_block_count(mp, nr),
+			       mp->m_sb.sb_blocksize);
+}
+
+/*
+ * Or, if it's a realtime file (t3):
+ *    the agf for each of the ags: 2 * sector size
+ *    the agfl for each of the ags: 2 * sector size
+ *    the super block to reflect the freed blocks: sector size
+ *    the realtime bitmap:
+ *		2 exts * ((XFS_BMBT_MAX_EXTLEN / rtextsize) / NBBY) bytes
+ *    the realtime summary: 2 exts * 1 block
+ *    worst case split in allocation btrees per extent assuming 2 extents:
+ *		2 exts * 2 trees * (2 * max depth - 1) * block size
+ */
+inline unsigned int
+xfs_calc_finish_rt_efi_reservation(
+	struct xfs_mount	*mp,
+	unsigned int		nr)
+{
+	if (!xfs_has_realtime(mp))
+		return 0;
+
+	return xfs_calc_buf_res((2 * nr) + 1, mp->m_sb.sb_sectsize) +
+	       xfs_calc_buf_res(xfs_rtalloc_block_count(mp, nr),
+			       mp->m_sb.sb_blocksize) +
+	       xfs_calc_buf_res(xfs_allocfree_block_count(mp, nr),
+			       mp->m_sb.sb_blocksize);
+}
+
+/*
+ * Finishing an RUI is the same as an EFI.  We can split the rmap btree twice
+ * on each end of the record, and that can cause the AGFL to be refilled or
+ * emptied out.
+ */
+inline unsigned int
+xfs_calc_finish_rui_reservation(
+	struct xfs_mount	*mp,
+	unsigned int		nr)
+{
+	if (!xfs_has_rmapbt(mp))
+		return 0;
+	return xfs_calc_finish_efi_reservation(mp, nr);
+}
+
+/*
+ * Finishing an RUI is the same as an EFI.  We can split the rmap btree twice
+ * on each end of the record, and that can cause the AGFL to be refilled or
+ * emptied out.
+ */
+inline unsigned int
+xfs_calc_finish_rt_rui_reservation(
+	struct xfs_mount	*mp,
+	unsigned int		nr)
+{
+	if (!xfs_has_rtrmapbt(mp))
+		return 0;
+	return xfs_calc_finish_rt_efi_reservation(mp, nr);
+}
+
+/*
+ * In finishing a BUI, we can modify:
+ *    the inode being truncated: inode size
+ *    dquots
+ *    the inode's bmap btree: (max depth + 1) * block size
+ */
+inline unsigned int
+xfs_calc_finish_bui_reservation(
+	struct xfs_mount	*mp,
+	unsigned int		nr)
+{
+	return xfs_calc_inode_res(mp, 1) + XFS_DQUOT_LOGRES +
+	       xfs_calc_buf_res(XFS_BM_MAXLEVELS(mp, XFS_DATA_FORK) + 1,
+			       mp->m_sb.sb_blocksize);
+}
+
+/*
  * In truncating a file we free up to two extents at once.  We can modify (t1):
  *    the inode being truncated: inode size
  *    the inode's bmap btree: (max depth + 1) * block size
@@ -411,16 +534,8 @@ xfs_calc_itruncate_reservation(
 	t1 = xfs_calc_inode_res(mp, 1) +
 	     xfs_calc_buf_res(XFS_BM_MAXLEVELS(mp, XFS_DATA_FORK) + 1, blksz);
 
-	t2 = xfs_calc_buf_res(9, mp->m_sb.sb_sectsize) +
-	     xfs_calc_buf_res(xfs_allocfree_block_count(mp, 4), blksz);
-
-	if (xfs_has_realtime(mp)) {
-		t3 = xfs_calc_buf_res(5, mp->m_sb.sb_sectsize) +
-		     xfs_calc_buf_res(xfs_rtalloc_block_count(mp, 2), blksz) +
-		     xfs_calc_buf_res(xfs_allocfree_block_count(mp, 2), blksz);
-	} else {
-		t3 = 0;
-	}
+	t2 = xfs_calc_finish_efi_reservation(mp, 4);
+	t3 = xfs_calc_finish_rt_efi_reservation(mp, 2);
 
 	/*
 	 * In the early days of reflink, we included enough reservation to log
@@ -501,9 +616,7 @@ xfs_calc_rename_reservation(
 	     xfs_calc_buf_res(2 * XFS_DIROP_LOG_COUNT(mp),
 			XFS_FSB_TO_B(mp, 1));
 
-	t2 = xfs_calc_buf_res(7, mp->m_sb.sb_sectsize) +
-	     xfs_calc_buf_res(xfs_allocfree_block_count(mp, 3),
-			XFS_FSB_TO_B(mp, 1));
+	t2 = xfs_calc_finish_efi_reservation(mp, 3);
 
 	if (xfs_has_parent(mp)) {
 		unsigned int	rename_overhead, exchange_overhead;
@@ -611,9 +724,7 @@ xfs_calc_link_reservation(
 	overhead += xfs_calc_iunlink_remove_reservation(mp);
 	t1 = xfs_calc_inode_res(mp, 2) +
 	     xfs_calc_buf_res(XFS_DIROP_LOG_COUNT(mp), XFS_FSB_TO_B(mp, 1));
-	t2 = xfs_calc_buf_res(3, mp->m_sb.sb_sectsize) +
-	     xfs_calc_buf_res(xfs_allocfree_block_count(mp, 1),
-			      XFS_FSB_TO_B(mp, 1));
+	t2 = xfs_calc_finish_efi_reservation(mp, 1);
 
 	if (xfs_has_parent(mp)) {
 		t3 = resp->tr_attrsetm.tr_logres;
@@ -676,9 +787,7 @@ xfs_calc_remove_reservation(
 
 	t1 = xfs_calc_inode_res(mp, 2) +
 	     xfs_calc_buf_res(XFS_DIROP_LOG_COUNT(mp), XFS_FSB_TO_B(mp, 1));
-	t2 = xfs_calc_buf_res(4, mp->m_sb.sb_sectsize) +
-	     xfs_calc_buf_res(xfs_allocfree_block_count(mp, 2),
-			      XFS_FSB_TO_B(mp, 1));
+	t2 = xfs_calc_finish_efi_reservation(mp, 2);
 
 	if (xfs_has_parent(mp)) {
 		t3 = resp->tr_attrrm.tr_logres;
@@ -1181,6 +1290,15 @@ xfs_calc_namespace_reservations(
 	resp->tr_mkdir.tr_logflags |= XFS_TRANS_PERM_LOG_RES;
 }
 
+STATIC void
+xfs_calc_default_atomic_ioend_reservation(
+	struct xfs_mount	*mp,
+	struct xfs_trans_resv	*resp)
+{
+	/* Pick a default that will scale reasonably for the log size. */
+	resp->tr_atomic_ioend = resp->tr_itruncate;
+}
+
 void
 xfs_trans_resv_calc(
 	struct xfs_mount	*mp,
@@ -1275,4 +1393,167 @@ xfs_trans_resv_calc(
 	resp->tr_itruncate.tr_logcount += logcount_adj;
 	resp->tr_write.tr_logcount += logcount_adj;
 	resp->tr_qm_dqalloc.tr_logcount += logcount_adj;
+
+	/*
+	 * Now that we've finished computing the static reservations, we can
+	 * compute the dynamic reservation for atomic writes.
+	 */
+	xfs_calc_default_atomic_ioend_reservation(mp, resp);
+}
+
+/*
+ * Return the per-extent and fixed transaction reservation sizes needed to
+ * complete an atomic write.
+ */
+STATIC unsigned int
+xfs_calc_atomic_write_ioend_geometry(
+	struct xfs_mount	*mp,
+	unsigned int		*step_size)
+{
+	const unsigned int	efi = xfs_efi_log_space(1);
+	const unsigned int	efd = xfs_efd_log_space(1);
+	const unsigned int	rui = xfs_rui_log_space(1);
+	const unsigned int	rud = xfs_rud_log_space();
+	const unsigned int	cui = xfs_cui_log_space(1);
+	const unsigned int	cud = xfs_cud_log_space();
+	const unsigned int	bui = xfs_bui_log_space(1);
+	const unsigned int	bud = xfs_bud_log_space();
+
+	/*
+	 * Maximum overhead to complete an atomic write ioend in software:
+	 * remove data fork extent + remove cow fork extent + map extent into
+	 * data fork.
+	 *
+	 * tx0: Creates a BUI and a CUI and that's all it needs.
+	 *
+	 * tx1: Roll to finish the BUI.  Need space for the BUD, an RUI, and
+	 * enough space to relog the CUI (== CUI + CUD).
+	 *
+	 * tx2: Roll again to finish the RUI.  Need space for the RUD and space
+	 * to relog the CUI.
+	 *
+	 * tx3: Roll again, need space for the CUD and possibly a new EFI.
+	 *
+	 * tx4: Roll again, need space for an EFD.
+	 *
+	 * If the extent referenced by the pair of BUI/CUI items is not the one
+	 * being currently processed, then we need to reserve space to relog
+	 * both items.
+	 */
+	const unsigned int	tx0 = bui + cui;
+	const unsigned int	tx1 = bud + rui + cui + cud;
+	const unsigned int	tx2 = rud + cui + cud;
+	const unsigned int	tx3 = cud + efi;
+	const unsigned int	tx4 = efd;
+	const unsigned int	relog = bui + bud + cui + cud;
+
+	const unsigned int	per_intent = max(max3(tx0, tx1, tx2),
+						 max3(tx3, tx4, relog));
+
+	/* Overhead to finish one step of each intent item type */
+	const unsigned int	f1 = xfs_calc_finish_efi_reservation(mp, 1);
+	const unsigned int	f2 = xfs_calc_finish_rui_reservation(mp, 1);
+	const unsigned int	f3 = xfs_calc_finish_cui_reservation(mp, 1);
+	const unsigned int	f4 = xfs_calc_finish_bui_reservation(mp, 1);
+
+	/* We only finish one item per transaction in a chain */
+	*step_size = max(f4, max3(f1, f2, f3));
+
+	return per_intent;
+}
+
+/*
+ * Compute the maximum size (in fsblocks) of atomic writes that we can complete
+ * given the existing log reservations.
+ */
+xfs_extlen_t
+xfs_calc_max_atomic_write_fsblocks(
+	struct xfs_mount		*mp)
+{
+	const struct xfs_trans_res	*resv = &M_RES(mp)->tr_atomic_ioend;
+	unsigned int			per_intent = 0;
+	unsigned int			step_size = 0;
+	unsigned int			ret = 0;
+
+	if (resv->tr_logres > 0) {
+		per_intent = xfs_calc_atomic_write_ioend_geometry(mp,
+				&step_size);
+
+		if (resv->tr_logres >= step_size)
+			ret = (resv->tr_logres - step_size) / per_intent;
+	}
+
+	trace_xfs_calc_max_atomic_write_fsblocks(mp, per_intent, step_size,
+			resv->tr_logres, ret);
+
+	return ret;
+}
+
+/*
+ * Compute the log blocks and transaction reservation needed to complete an
+ * atomic write of a given number of blocks.  Worst case, each block requires
+ * separate handling.  A return value of 0 means something went wrong.
+ */
+xfs_extlen_t
+xfs_calc_atomic_write_log_geometry(
+	struct xfs_mount	*mp,
+	xfs_extlen_t		blockcount,
+	unsigned int		*new_logres)
+{
+	struct xfs_trans_res	*curr_res = &M_RES(mp)->tr_atomic_ioend;
+	uint			old_logres = curr_res->tr_logres;
+	unsigned int		per_intent, step_size;
+	unsigned int		logres;
+	xfs_extlen_t		min_logblocks;
+
+	ASSERT(blockcount > 0);
+
+	xfs_calc_default_atomic_ioend_reservation(mp, M_RES(mp));
+
+	per_intent = xfs_calc_atomic_write_ioend_geometry(mp, &step_size);
+
+	/* Check for overflows */
+	if (check_mul_overflow(blockcount, per_intent, &logres) ||
+	    check_add_overflow(logres, step_size, &logres))
+		return 0;
+
+	curr_res->tr_logres = logres;
+	min_logblocks = xfs_log_calc_minimum_size(mp);
+	curr_res->tr_logres = old_logres;
+
+	trace_xfs_calc_max_atomic_write_log_geometry(mp, per_intent, step_size,
+			blockcount, min_logblocks, logres);
+
+	*new_logres = logres;
+	return min_logblocks;
+}
+
+/*
+ * Compute the transaction reservation needed to complete an out of place
+ * atomic write of a given number of blocks.
+ */
+int
+xfs_calc_atomic_write_reservation(
+	struct xfs_mount	*mp,
+	xfs_extlen_t		blockcount)
+{
+	unsigned int		new_logres;
+	xfs_extlen_t		min_logblocks;
+
+	/*
+	 * If the caller doesn't ask for a specific atomic write size, then
+	 * use the defaults.
+	 */
+	if (blockcount == 0) {
+		xfs_calc_default_atomic_ioend_reservation(mp, M_RES(mp));
+		return 0;
+	}
+
+	min_logblocks = xfs_calc_atomic_write_log_geometry(mp, blockcount,
+			&new_logres);
+	if (!min_logblocks || min_logblocks > mp->m_sb.sb_logblocks)
+		return -EINVAL;
+
+	M_RES(mp)->tr_atomic_ioend.tr_logres = new_logres;
+	return 0;
 }