Set zp->z-blksz to ashift if larger

This is in interaction with zfs-write-log() which uses z-blksz to determine chunking sizes, which can be heavily penalised when devices have larger blocksizes, using read/copy/write for each IO. Signed-off-by: Jorgen Lundman <[email protected]>
openzfsonwindows · Nov 8, 2023 · f0e86b4 · f0e86b4
1 parent bc14612
commit f0e86b4
Showing 1 changed file with 6 additions and 0 deletions.
diff --git a/module/os/windows/zfs/zfs_znode.c b/module/os/windows/zfs/zfs_znode.c
@@ -69,6 +69,8 @@
 #include <sys/zfs_sa.h>
 #include <sys/zfs_stat.h>
 
+#include <sys/spa_impl.h> // spa_min_alloc
+
 #include "zfs_prop.h"
 #include "zfs_comutil.h"
 
@@ -627,6 +629,10 @@ zfs_znode_alloc(zfsvfs_t *zfsvfs, dmu_buf_t *db, int blksz,
 	if (zp->z_blksz == 0)
 		zp->z_blksz = zfs_blksz(zp);
 
+	/* This makes a large difference on 4096 block devices */
+	if (zfsvfs->z_os->os_spa->spa_min_alloc > zp->z_blksz)
+		zp->z_blksz = zfsvfs->z_os->os_spa->spa_min_alloc;
+
 	return (zp);
 }