Illumos 4757, 4913

4757 ZFS embedded-data block pointers ("zero block compression")
4913 zfs release should not be subject to space checks

Reviewed by: Adam Leventhal <[email protected]>
Reviewed by: Max Grossman <[email protected]>
Reviewed by: George Wilson <[email protected]>
Reviewed by: Christopher Siden <[email protected]>
Reviewed by: Dan McDonald <[email protected]>
Approved by: Dan McDonald <[email protected]>

References:
  https://www.illumos.org/issues/4757
  https://www.illumos.org/issues/4913
  https://github.com/illumos/illumos-gate/commit/5d7b4d4

Porting notes:

For compatibility with the fastpath code the zio_done() function
needed to be updated.  Because embedded-data block pointers do
not require DVAs to be allocated the associated vdevs will not
be marked and therefore should not be unmarked.

Ported by: Tim Chase <[email protected]>
Signed-off-by: Brian Behlendorf <[email protected]>
Closes #2544

1 files changed, 2 insertions, 17 deletions

diff --git a/module/zfs/zio_compress.c b/module/zfs/zio_compress.c
index 5b63f0aa0..074462349 100644
--- a/module/zfs/zio_compress.c
+++ b/module/zfs/zio_compress.c
@@ -80,7 +80,7 @@ size_t
 zio_compress_data(enum zio_compress c, void *src, void *dst, size_t s_len)
 {
 	uint64_t *word, *word_end;
-	size_t c_len, d_len, r_len;
+	size_t c_len, d_len;
 	zio_compress_info_t *ci = &zio_compress_table[c];
 
 	ASSERT((uint_t)c < ZIO_COMPRESS_FUNCTIONS);
@@ -102,28 +102,13 @@ zio_compress_data(enum zio_compress c, void *src, void *dst, size_t s_len)
 		return (s_len);
 
 	/* Compress at least 12.5% */
-	d_len = P2ALIGN(s_len - (s_len >> 3), (size_t)SPA_MINBLOCKSIZE);
-	if (d_len == 0)
-		return (s_len);
-
+	d_len = s_len - (s_len >> 3);
 	c_len = ci->ci_compress(src, dst, s_len, d_len, ci->ci_level);
 
 	if (c_len > d_len)
 		return (s_len);
 
-	/*
-	 * Cool.  We compressed at least as much as we were hoping to.
-	 * For both security and repeatability, pad out the last sector.
-	 */
-	r_len = P2ROUNDUP(c_len, (size_t)SPA_MINBLOCKSIZE);
-	if (r_len > c_len) {
-		bzero((char *)dst + c_len, r_len - c_len);
-		c_len = r_len;
-	}
-
 	ASSERT3U(c_len, <=, d_len);
-	ASSERT(P2PHASE(c_len, (size_t)SPA_MINBLOCKSIZE) == 0);
-
 	return (c_len);
 }