Enable raw writes to perform dedup with verification

Reviewed by: Dan Kimmel <[email protected]>
Reviewed by: Brian Behlendorf <[email protected]>
Reviewed by: David Quigley <[email protected]>
Signed-off-by: Tom Caputi <[email protected]>
Issue #5078

1 files changed, 49 insertions, 7 deletions

diff --git a/module/zfs/zio.c b/module/zfs/zio.c
index 892b86fba..e26822e34 100644
--- a/module/zfs/zio.c
+++ b/module/zfs/zio.c
@@ -2363,19 +2363,30 @@ zio_ddt_collision(zio_t *zio, ddt_t *ddt, ddt_entry_t *dde)
 {
 	spa_t *spa = zio->io_spa;
 	int p;
+	boolean_t do_raw = !!(zio->io_flags & ZIO_FLAG_RAW);
 
-	ASSERT0(zio->io_flags & ZIO_FLAG_RAW);
+	ASSERT(!(zio->io_bp_override && do_raw));
 
 	/*
 	 * Note: we compare the original data, not the transformed data,
 	 * because when zio->io_bp is an override bp, we will not have
 	 * pushed the I/O transforms.  That's an important optimization
 	 * because otherwise we'd compress/encrypt all dmu_sync() data twice.
+	 * However, we should never get a raw, override zio so in these
+	 * cases we can compare the io_data directly. This is useful because
+	 * it allows us to do dedup verification even if we don't have access
+	 * to the original data (for instance, if the encryption keys aren't
+	 * loaded).
 	 */
+
 	for (p = DDT_PHYS_SINGLE; p <= DDT_PHYS_TRIPLE; p++) {
 		zio_t *lio = dde->dde_lead_zio[p];
 
-		if (lio != NULL) {
+		if (lio != NULL && do_raw) {
+			return (lio->io_size != zio->io_size ||
+			    bcmp(zio->io_data, lio->io_data,
+			    zio->io_size) != 0);
+		} else if (lio != NULL) {
 			return (lio->io_orig_size != zio->io_orig_size ||
 			    bcmp(zio->io_orig_data, lio->io_orig_data,
 			    zio->io_orig_size) != 0);
@@ -2385,7 +2396,36 @@ zio_ddt_collision(zio_t *zio, ddt_t *ddt, ddt_entry_t *dde)
 	for (p = DDT_PHYS_SINGLE; p <= DDT_PHYS_TRIPLE; p++) {
 		ddt_phys_t *ddp = &dde->dde_phys[p];
 
-		if (ddp->ddp_phys_birth != 0) {
+		if (ddp->ddp_phys_birth != 0 && do_raw) {
+			blkptr_t blk = *zio->io_bp;
+			uint64_t psize;
+			void *tmpbuf;
+			int error;
+
+			ddt_bp_fill(ddp, &blk, ddp->ddp_phys_birth);
+			psize = BP_GET_PSIZE(&blk);
+
+			if (psize != zio->io_size)
+				return (B_TRUE);
+
+			ddt_exit(ddt);
+
+			tmpbuf = zio_buf_alloc(psize);
+
+			error = zio_wait(zio_read(NULL, spa, &blk, tmpbuf,
+			    psize, NULL, NULL, ZIO_PRIORITY_SYNC_READ,
+			    ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE |
+			    ZIO_FLAG_RAW, &zio->io_bookmark));
+
+			if (error == 0) {
+				if (bcmp(tmpbuf, zio->io_data, psize) != 0)
+					error = SET_ERROR(ENOENT);
+			}
+
+			zio_buf_free(tmpbuf, psize);
+			ddt_enter(ddt);
+			return (error != 0);
+		} else if (ddp->ddp_phys_birth != 0) {
 			arc_buf_t *abuf = NULL;
 			arc_flags_t aflags = ARC_FLAG_WAIT;
 			blkptr_t blk = *zio->io_bp;
@@ -2393,6 +2433,9 @@ zio_ddt_collision(zio_t *zio, ddt_t *ddt, ddt_entry_t *dde)
 
 			ddt_bp_fill(ddp, &blk, ddp->ddp_phys_birth);
 
+			if (BP_GET_LSIZE(&blk) != zio->io_orig_size)
+				return (B_TRUE);
+
 			ddt_exit(ddt);
 
 			error = arc_read(NULL, spa, &blk,
@@ -2401,10 +2444,9 @@ zio_ddt_collision(zio_t *zio, ddt_t *ddt, ddt_entry_t *dde)
 			    &aflags, &zio->io_bookmark);
 
 			if (error == 0) {
-				if (arc_buf_size(abuf) != zio->io_orig_size ||
-				    bcmp(abuf->b_data, zio->io_orig_data,
+				if (bcmp(abuf->b_data, zio->io_orig_data,
 				    zio->io_orig_size) != 0)
-					error = SET_ERROR(EEXIST);
+					error = SET_ERROR(ENOENT);
 				arc_buf_destroy(abuf, &abuf);
 			}
 
@@ -2511,7 +2553,7 @@ zio_ddt_write(zio_t *zio)
 	ASSERT(BP_GET_DEDUP(bp));
 	ASSERT(BP_GET_CHECKSUM(bp) == zp->zp_checksum);
 	ASSERT(BP_IS_HOLE(bp) || zio->io_bp_override);
-	ASSERT0(zio->io_flags & ZIO_FLAG_RAW);
+	ASSERT(!(zio->io_bp_override && (zio->io_flags & ZIO_FLAG_RAW)));
 
 	ddt_enter(ddt);
 	dde = ddt_lookup(ddt, bp, B_TRUE);