ZLE compression: don't use BPE_PAYLOAD_SIZE

ZLE compressor needs additional bytes to process
d_len argument efficiently.
Don't use BPE_PAYLOAD_SIZE as d_len with it
before we rework zle compressor somehow.

Reviewed-by: Brian Behlendorf <[email protected]>
Reviewed-by: Tony Hutter <[email protected]>
Reviewed-by: Alexander Motin <[email protected]>
Signed-off-by: George Melikov <[email protected]>
Closes openzfs#9416

Author: gmelikov

include/sys/zio.h

@@ -608,8 +608,8 @@ extern int zio_alloc_zil(spa_t *spa, objset_t *os, uint64_t txg,
 extern void zio_flush(zio_t *zio, vdev_t *vd);
 extern void zio_shrink(zio_t *zio, uint64_t size);
 
-extern size_t zio_get_compression_max_size(uint64_t gcd_alloc,
-    uint64_t min_alloc, size_t s_len);
+extern size_t zio_get_compression_max_size(enum zio_compress compress,
+    uint64_t gcd_alloc, uint64_t min_alloc, size_t s_len);
 extern int zio_wait(zio_t *zio);
 extern void zio_nowait(zio_t *zio);
 extern void zio_execute(void *zio);

module/zfs/arc.c

@@ -10525,7 +10525,8 @@ l2arc_log_blk_commit(l2arc_dev_t *dev, zio_t *pio, l2arc_write_callback_t *cb)
 	/* try to compress the buffer, at least one sector to save */
 	psize = zio_compress_data(ZIO_COMPRESS_LZ4,
 	    abd_buf->abd, &abd, sizeof (*lb),
-	    zio_get_compression_max_size(dev->l2ad_vdev->vdev_ashift,
+	    zio_get_compression_max_size(ZIO_COMPRESS_LZ4,
+	    dev->l2ad_vdev->vdev_ashift,
 	    dev->l2ad_vdev->vdev_ashift, sizeof (*lb)), 0);
 
 	/* a log block is never entirely zero */

module/zfs/zio.c

@@ -1706,15 +1706,20 @@ zio_roundup_alloc_size(spa_t *spa, uint64_t size)
 }
 
 size_t
-zio_get_compression_max_size(uint64_t gcd_alloc, uint64_t min_alloc,
-    size_t s_len)
+zio_get_compression_max_size(enum zio_compress compress, uint64_t gcd_alloc,
+    uint64_t min_alloc, size_t s_len)
 {
 	size_t d_len;
 
 	/* minimum 12.5% must be saved (legacy value, may be changed later) */
 	d_len = s_len - (s_len >> 3);
 
+	/* ZLE can't use exactly d_len bytes, it needs more, so ignore it */
+	if (compress == ZIO_COMPRESS_ZLE)
+		return (d_len);
+
 	d_len = d_len - d_len % gcd_alloc;
+
 	if (d_len < min_alloc)
 		return (BPE_PAYLOAD_SIZE);
 	return (d_len);
@@ -1902,8 +1907,8 @@ zio_write_compress(zio_t *zio)
 		else
 			psize = zio_compress_data(compress, zio->io_abd, &cabd,
 			    lsize,
-			    zio_get_compression_max_size(spa->spa_gcd_alloc,
-			    spa->spa_min_alloc, lsize),
+			    zio_get_compression_max_size(compress,
+			    spa->spa_gcd_alloc, spa->spa_min_alloc, lsize),
 			    zp->zp_complevel);
 		if (psize == 0) {
 			compress = ZIO_COMPRESS_OFF;