Illumos 5369 - arc flags should be an enum

5369 arc flags should be an enum
5370 consistent arc_buf_hdr_t naming scheme
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Alex Reece <alex.reece@delphix.com>
Reviewed by: Sebastien Roy <sebastien.roy@delphix.com>
Reviewed by: Richard Elling <richard.elling@richardelling.com>
Approved by: Richard Lowe <richlowe@richlowe.net>

changes due to openzfs#2129, in:

keeping changes in include/sys/arc.h from openzfs#2129
keeping changes in module/zfs/dmu_traverse.c from openzfs#3254 ( 0c66c32 )

conflicts due to openzfs#2129, in:

fix commit 989fd51
"Change ASSERT(!"...") to  cmn_err(CE_PANIC, ...)"

changed ARC_PREFETCH to ARC_FLAG_PREFETCH

several ab->b to hdr->b changes

cmd/zdb/zdb.c

@@ -1171,7 +1171,7 @@ visit_indirect(spa_t *spa, const dnode_phys_t *dnp,
 	print_indirect(bp, zb, dnp);
 
 	if (BP_GET_LEVEL(bp) > 0 && !BP_IS_HOLE(bp)) {
-		uint32_t flags = ARC_WAIT;
+		arc_flags_t flags = ARC_FLAG_WAIT;
 		int i;
 		blkptr_t *cbp;
 		int epb = BP_GET_LSIZE(bp) >> SPA_BLKPTRSHIFT;

include/sys/arc.h

@@ -58,6 +58,36 @@ struct arc_prune {
 	refcount_t		p_refcnt;
 };
 
+typedef enum arc_flags
+{
+	/*
+	 * Public flags that can be passed into the ARC by external consumers.
+	 */
+	ARC_FLAG_NONE			= 1 << 0,	/* No flags set */
+	ARC_FLAG_WAIT			= 1 << 1,	/* perform sync I/O */
+	ARC_FLAG_NOWAIT			= 1 << 2,	/* perform async I/O */
+	ARC_FLAG_PREFETCH		= 1 << 3,	/* I/O is a prefetch */
+	ARC_FLAG_CACHED			= 1 << 4,	/* I/O was in cache */
+	ARC_FLAG_L2CACHE		= 1 << 5,	/* cache in L2ARC */
+	ARC_FLAG_L2COMPRESS		= 1 << 6,	/* compress in L2ARC */
+
+	/*
+	 * Private ARC flags.  These flags are private ARC only flags that
+	 * will show up in b_flags in the arc_hdr_buf_t. These flags should
+	 * only be set by ARC code.
+	 */
+	ARC_FLAG_IN_HASH_TABLE		= 1 << 7,	/* buffer is hashed */
+	ARC_FLAG_IO_IN_PROGRESS		= 1 << 8,	/* I/O in progress */
+	ARC_FLAG_IO_ERROR		= 1 << 9,	/* I/O failed for buf */
+	ARC_FLAG_FREED_IN_READ		= 1 << 10,	/* freed during read */
+	ARC_FLAG_BUF_AVAILABLE		= 1 << 11,	/* block not in use */
+	ARC_FLAG_INDIRECT		= 1 << 12,	/* indirect block */
+	ARC_FLAG_FREE_IN_PROGRESS	= 1 << 13,	/*  about to be freed */
+	ARC_FLAG_L2_WRITING		= 1 << 14,	/* write in progress */
+	ARC_FLAG_L2_EVICTED		= 1 << 15,	/* evicted during I/O */
+	ARC_FLAG_L2_WRITE_HEAD		= 1 << 16,	/* head of write list */
+} arc_flags_t;
+
 struct arc_buf {
 	arc_buf_hdr_t		*b_hdr;
 	arc_buf_t		*b_next;
@@ -160,7 +190,7 @@ int arc_referenced(arc_buf_t *buf);
 
 int arc_read(zio_t *pio, spa_t *spa, const blkptr_t *bp,
     arc_done_func_t *done, void *private, zio_priority_t priority, int flags,
-    uint32_t *arc_flags, const zbookmark_phys_t *zb);
+    arc_flags_t *arc_flags, const zbookmark_phys_t *zb);
 zio_t *arc_write(zio_t *pio, spa_t *spa, uint64_t txg,
     blkptr_t *bp, arc_buf_t *buf, boolean_t l2arc, boolean_t l2arc_compress,
     const zio_prop_t *zp, arc_done_func_t *ready, arc_done_func_t *physdone,

include/sys/arc_impl.h

@@ -107,7 +107,7 @@ struct arc_buf_hdr {
 
 	arc_buf_hdr_t		*b_hash_next;
 	arc_buf_t		*b_buf;
-	uint32_t		b_flags;
+	arc_flags_t		b_flags;
 	uint32_t		b_datacnt;
 
 	arc_callback_t		*b_acb;