]> git.saurik.com Git - apple/xnu.git/blobdiff - bsd/vfs/vfs_bio.c
xnu-2782.40.9.tar.gz
[apple/xnu.git] / bsd / vfs / vfs_bio.c
index 7f4ee03e561b4c18ddb8eb233329f6f2a9dbdb06..c6e919d9e806e19ca306a9c397a5da52a2207649 100644 (file)
@@ -1,31 +1,29 @@
 /*
- * Copyright (c) 2006 Apple Computer, Inc. All Rights Reserved.
+ * Copyright (c) 2000-2014 Apple Inc. All rights reserved.
+ *
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
  * 
- * @APPLE_LICENSE_OSREFERENCE_HEADER_START@
+ * This file contains Original Code and/or Modifications of Original Code
+ * as defined in and that are subject to the Apple Public Source License
+ * Version 2.0 (the 'License'). You may not use this file except in
+ * compliance with the License. The rights granted to you under the License
+ * may not be used to create, or enable the creation or redistribution of,
+ * unlawful or unlicensed copies of an Apple operating system, or to
+ * circumvent, violate, or enable the circumvention or violation of, any
+ * terms of an Apple operating system software license agreement.
  * 
- * This file contains Original Code and/or Modifications of Original Code 
- * as defined in and that are subject to the Apple Public Source License 
- * Version 2.0 (the 'License'). You may not use this file except in 
- * compliance with the License.  The rights granted to you under the 
- * License may not be used to create, or enable the creation or 
- * redistribution of, unlawful or unlicensed copies of an Apple operating 
- * system, or to circumvent, violate, or enable the circumvention or 
- * violation of, any terms of an Apple operating system software license 
- * agreement.
- *
- * Please obtain a copy of the License at 
- * http://www.opensource.apple.com/apsl/ and read it before using this 
- * file.
- *
- * The Original Code and all software distributed under the License are 
- * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER 
- * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, 
- * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, 
- * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. 
- * Please see the License for the specific language governing rights and 
+ * Please obtain a copy of the License at
+ * http://www.opensource.apple.com/apsl/ and read it before using this file.
+ * 
+ * The Original Code and all software distributed under the License are
+ * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
+ * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
+ * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
+ * Please see the License for the specific language governing rights and
  * limitations under the License.
- *
- * @APPLE_LICENSE_OSREFERENCE_HEADER_END@
+ * 
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  */
 /* Copyright (c) 1995 NeXT Computer, Inc. All Rights Reserved */
 /*-
 #endif /* DIAGNOSTIC */
 #include <kern/task.h>
 #include <kern/zalloc.h>
-#include <kern/lock.h>
+#include <kern/locks.h>
+#include <kern/thread.h>
+
+#include <sys/fslog.h>         /* fslog_io_error() */
+
+#include <mach/mach_types.h>
+#include <mach/memory_object_types.h>
+#include <kern/sched_prim.h>   /* thread_block() */
 
 #include <vm/vm_kern.h>
+#include <vm/vm_pageout.h>
 
 #include <sys/kdebug.h>
-#include <machine/spl.h>
 
-#if BALANCE_QUEUES
-static __inline__ void bufqinc(int q);
-static __inline__ void bufqdec(int q);
-#endif
+#include <libkern/OSAtomic.h>
+#include <libkern/OSDebug.h>
+#include <sys/ubc_internal.h>
+
+#include <sys/sdt.h>
+#include <sys/cprotect.h>
 
-static int     bcleanbuf(buf_t bp);
+int    bcleanbuf(buf_t bp, boolean_t discard);
 static int     brecover_data(buf_t bp);
 static boolean_t incore(vnode_t vp, daddr64_t blkno);
-static buf_t   incore_locked(vnode_t vp, daddr64_t blkno);
 /* timeout is in msecs */
 static buf_t   getnewbuf(int slpflag, int slptimeo, int *queue);
 static void    bremfree_locked(buf_t bp);
@@ -116,6 +122,13 @@ static void        buf_reassign(buf_t bp, vnode_t newvp);
 static errno_t buf_acquire_locked(buf_t bp, int flags, int slpflag, int slptimeo);
 static int     buf_iterprepare(vnode_t vp, struct buflists *, int flags);
 static void    buf_itercomplete(vnode_t vp, struct buflists *, int flags);
+static boolean_t buffer_cache_gc(int);
+static buf_t   buf_brelse_shadow(buf_t bp);
+static void    buf_free_meta_store(buf_t bp);
+
+static buf_t   buf_create_shadow_internal(buf_t bp, boolean_t force_copy,
+                                          uintptr_t external_storage, void (*iodone)(buf_t, void *), void *arg, int priv);
+
 
 __private_extern__ int  bdwrite_internal(buf_t, int);
 
@@ -136,13 +149,17 @@ static int        buf_hdr_count;
 LIST_HEAD(bufhashhdr, buf) *bufhashtbl, invalhash;
 u_long bufhash;
 
+static buf_t   incore_locked(vnode_t vp, daddr64_t blkno, struct bufhashhdr *dp);
+
 /* Definitions for the buffer stats. */
 struct bufstats bufstats;
 
 /* Number of delayed write buffers */
-int nbdwrite = 0;
+long nbdwrite = 0;
 int blaundrycnt = 0;
+static int boot_nbuf_headers = 0;
 
+static TAILQ_HEAD(delayqueue, buf) delaybufqueue;
 
 static TAILQ_HEAD(ioqueue, buf) iobufqueue;
 static TAILQ_HEAD(bqueues, buf) bufqueues[BQUEUES];
@@ -155,6 +172,8 @@ static lck_grp_attr_t   *buf_mtx_grp_attr;
 static lck_mtx_t       *iobuffer_mtxp;
 static lck_mtx_t       *buf_mtxp;
 
+static int buf_busycount;
+
 static __inline__ int
 buf_timestamp(void)
 {
@@ -166,38 +185,17 @@ buf_timestamp(void)
 /*
  * Insq/Remq for the buffer free lists.
  */
-#if BALANCE_QUEUES
 #define        binsheadfree(bp, dp, whichq)    do { \
                                    TAILQ_INSERT_HEAD(dp, bp, b_freelist); \
-                                       bufqinc((whichq));      \
-                                       (bp)->b_whichq = whichq; \
-                                   (bp)->b_timestamp = buf_timestamp(); \
                                } while (0)
 
 #define        binstailfree(bp, dp, whichq)    do { \
                                    TAILQ_INSERT_TAIL(dp, bp, b_freelist); \
-                                       bufqinc((whichq));      \
-                                       (bp)->b_whichq = whichq; \
-                                   (bp)->b_timestamp = buf_timestamp(); \
                                } while (0)
-#else
-#define        binsheadfree(bp, dp, whichq)    do { \
-                                   TAILQ_INSERT_HEAD(dp, bp, b_freelist); \
-                                       (bp)->b_whichq = whichq; \
-                                   (bp)->b_timestamp = buf_timestamp(); \
-                               } while (0)
-
-#define        binstailfree(bp, dp, whichq)    do { \
-                                   TAILQ_INSERT_TAIL(dp, bp, b_freelist); \
-                                       (bp)->b_whichq = whichq; \
-                                   (bp)->b_timestamp = buf_timestamp(); \
-                               } while (0)
-#endif
-
 
 #define BHASHENTCHECK(bp)      \
        if ((bp)->b_hash.le_prev != (struct buf **)0xdeadbeef)  \
-               panic("%x: b_hash.le_prev is not deadbeef", (bp));
+               panic("%p: b_hash.le_prev is not deadbeef", (bp));
 
 #define BLISTNONE(bp)  \
        (bp)->b_hash.le_next = (struct buf *)0; \
@@ -224,7 +222,7 @@ int lru_is_stale = LRU_IS_STALE;
 int age_is_stale = AGE_IS_STALE;
 int meta_is_stale = META_IS_STALE;
 
-
+#define MAXLAUNDRY     10
 
 /* LIST_INSERT_HEAD() with assertions */
 static __inline__ void
@@ -241,15 +239,19 @@ blistenterhead(struct bufhashhdr * head, buf_t bp)
 static __inline__ void 
 binshash(buf_t bp, struct bufhashhdr *dp)
 {
+#if DIAGNOSTIC
        buf_t   nbp;
+#endif /* DIAGNOSTIC */
 
        BHASHENTCHECK(bp);
 
+#if DIAGNOSTIC
        nbp = dp->lh_first;
        for(; nbp != NULL; nbp = nbp->b_hash.le_next) {
                if(nbp == bp) 
                        panic("buf already in hashlist");
        }
+#endif /* DIAGNOSTIC */
 
        blistenterhead(dp, bp);
 }
@@ -267,7 +269,28 @@ bremhash(buf_t     bp)
        *bp->b_hash.le_prev = (bp)->b_hash.le_next;
 }
 
+/*
+ * buf_mtxp held.
+ */
+static __inline__ void
+bmovelaundry(buf_t bp)
+{
+       bp->b_whichq = BQ_LAUNDRY;
+       bp->b_timestamp = buf_timestamp();
+       binstailfree(bp, &bufqueues[BQ_LAUNDRY], BQ_LAUNDRY);
+       blaundrycnt++;
+}
 
+static __inline__ void
+buf_release_credentials(buf_t bp)
+{
+       if (IS_VALID_CRED(bp->b_rcred)) {
+               kauth_cred_unref(&bp->b_rcred);
+       }
+       if (IS_VALID_CRED(bp->b_wcred)) {
+               kauth_cred_unref(&bp->b_wcred);
+       }
+}
 
 
 int
@@ -295,8 +318,24 @@ buf_markinvalid(buf_t bp) {
 void
 buf_markdelayed(buf_t bp) {
   
-        SET(bp->b_flags, B_DELWRI);
-       buf_reassign(bp, bp->b_vp);
+       if (!ISSET(bp->b_flags, B_DELWRI)) {
+               SET(bp->b_flags, B_DELWRI);
+
+               OSAddAtomicLong(1, &nbdwrite);
+               buf_reassign(bp, bp->b_vp);
+       }
+        SET(bp->b_flags, B_DONE);
+}
+
+void
+buf_markclean(buf_t bp) {
+
+       if (ISSET(bp->b_flags, B_DELWRI)) {
+               CLR(bp->b_flags, B_DELWRI);
+
+               OSAddAtomicLong(-1, &nbdwrite);
+               buf_reassign(bp, bp->b_vp);
+       }
 }
 
 void
@@ -305,12 +344,207 @@ buf_markeintr(buf_t bp) {
         SET(bp->b_flags, B_EINTR);
 }
 
+
 void
 buf_markaged(buf_t bp) {
   
         SET(bp->b_flags, B_AGE);
 }
 
+int
+buf_fua(buf_t bp) {
+
+        if ((bp->b_flags & B_FUA) == B_FUA)
+               return 1;
+       return 0;
+}
+
+void 
+buf_markfua(buf_t bp) {
+
+        SET(bp->b_flags, B_FUA);
+}
+
+#if CONFIG_PROTECT
+void
+buf_setcpaddr(buf_t bp, struct cprotect *entry) {
+       bp->b_attr.ba_cpentry = entry;
+}
+
+void
+buf_setcpoff (buf_t bp, uint64_t foffset) {
+       bp->b_attr.ba_cp_file_off = foffset;
+}
+
+void *
+bufattr_cpaddr(bufattr_t bap) {
+       return (bap->ba_cpentry);
+}
+
+uint64_t
+bufattr_cpoff(bufattr_t bap) {
+       return (bap->ba_cp_file_off);
+}
+
+void
+bufattr_setcpaddr(bufattr_t bap, void *cp_entry_addr) {
+        bap->ba_cpentry = cp_entry_addr;
+}
+
+void
+bufattr_setcpoff(bufattr_t bap, uint64_t foffset) {
+        bap->ba_cp_file_off = foffset;
+}
+
+#else
+void *
+bufattr_cpaddr(bufattr_t bap __unused) {
+        return NULL;
+}
+
+uint64_t
+bufattr_cpoff(bufattr_t bap __unused) {
+       return 0;
+}
+
+void
+bufattr_setcpaddr(bufattr_t bap __unused, void *cp_entry_addr __unused) {
+}
+
+void
+bufattr_setcpoff(__unused bufattr_t bap, __unused uint64_t foffset) {
+       return;
+}
+#endif /* CONFIG_PROTECT */
+
+bufattr_t
+bufattr_alloc() {
+       bufattr_t bap;
+       MALLOC(bap, bufattr_t, sizeof(struct bufattr), M_TEMP, M_WAITOK);
+       if (bap == NULL)
+               return NULL;
+
+       bzero(bap, sizeof(struct bufattr));
+       return bap;
+}
+
+void
+bufattr_free(bufattr_t bap) {
+       if (bap)
+               FREE(bap, M_TEMP);
+}
+
+bufattr_t
+bufattr_dup(bufattr_t bap) {
+       bufattr_t new_bufattr;
+       MALLOC(new_bufattr, bufattr_t, sizeof(struct bufattr), M_TEMP, M_WAITOK);
+       if (new_bufattr == NULL)
+               return NULL;
+
+       /* Copy the provided one into the new copy */
+       memcpy (new_bufattr, bap, sizeof(struct bufattr));
+       return new_bufattr;
+}
+
+int
+bufattr_rawencrypted(bufattr_t bap) {
+       if ( (bap->ba_flags & BA_RAW_ENCRYPTED_IO) )
+               return 1;
+       return 0;
+}
+
+int
+bufattr_throttled(bufattr_t bap) {
+       return (GET_BUFATTR_IO_TIER(bap));
+}
+
+int
+bufattr_passive(bufattr_t bap) {
+       if ( (bap->ba_flags & BA_PASSIVE) )
+               return 1;
+       return 0;
+}
+
+int
+bufattr_nocache(bufattr_t bap) {
+       if ( (bap->ba_flags & BA_NOCACHE) )
+               return 1;
+       return 0;
+}
+
+int
+bufattr_meta(bufattr_t bap) {
+       if ( (bap->ba_flags & BA_META) )
+               return 1;
+       return 0;
+}
+
+void
+bufattr_markmeta(bufattr_t bap) {
+       SET(bap->ba_flags,  BA_META);
+}
+
+int
+bufattr_delayidlesleep(bufattr_t bap) 
+{
+       if ( (bap->ba_flags & BA_DELAYIDLESLEEP) )
+               return 1;
+       return 0;
+}
+
+bufattr_t
+buf_attr(buf_t bp) {
+       return &bp->b_attr;
+}
+
+void 
+buf_markstatic(buf_t bp __unused) {
+       SET(bp->b_flags, B_STATICCONTENT);
+}
+
+int
+buf_static(buf_t bp) {
+    if ( (bp->b_flags & B_STATICCONTENT) )
+        return 1;
+    return 0;
+}
+
+void 
+bufattr_markgreedymode(bufattr_t bap) {
+       SET(bap->ba_flags, BA_GREEDY_MODE);
+}
+
+int
+bufattr_greedymode(bufattr_t bap) {
+    if ( (bap->ba_flags & BA_GREEDY_MODE) )
+        return 1;
+    return 0;
+}
+
+void 
+bufattr_markisochronous(bufattr_t bap) {
+       SET(bap->ba_flags, BA_ISOCHRONOUS);
+}
+
+int
+bufattr_isochronous(bufattr_t bap) {
+    if ( (bap->ba_flags & BA_ISOCHRONOUS) )
+        return 1;
+    return 0;
+}
+
+void 
+bufattr_markquickcomplete(bufattr_t bap) {
+       SET(bap->ba_flags, BA_QUICK_COMPLETE);
+}
+
+int
+bufattr_quickcomplete(bufattr_t bap) {
+    if ( (bap->ba_flags & BA_QUICK_COMPLETE) )
+        return 1;
+    return 0;
+}
+
 errno_t
 buf_error(buf_t bp) {
         
@@ -347,7 +581,7 @@ buf_flags(buf_t bp) {
 void
 buf_reset(buf_t bp, int32_t io_flags) {
         
-        CLR(bp->b_flags, (B_READ | B_WRITE | B_ERROR | B_DONE | B_INVAL | B_ASYNC | B_NOCACHE));
+        CLR(bp->b_flags, (B_READ | B_WRITE | B_ERROR | B_DONE | B_INVAL | B_ASYNC | B_NOCACHE | B_FUA));
        SET(bp->b_flags, (io_flags & (B_ASYNC | B_READ | B_WRITE | B_NOCACHE)));
 
        bp->b_error = 0;
@@ -441,8 +675,6 @@ buf_setvnode(buf_t bp, vnode_t vp) {
 void *
 buf_callback(buf_t bp)
 {
-        if ( !(bp->b_lflags & BL_IOBUF) )
-               return ((void *) NULL);
         if ( !(bp->b_flags & B_CALL) )
                return ((void *) NULL);
 
@@ -453,10 +685,6 @@ buf_callback(buf_t bp)
 errno_t
 buf_setcallback(buf_t bp, void (*callback)(buf_t, void *), void *transaction)
 {
-
-        if ( !(bp->b_lflags & BL_IOBUF) )
-               return (EINVAL);
-       
        if (callback)
                bp->b_flags |= (B_CALL | B_ASYNC);
        else
@@ -504,7 +732,7 @@ buf_clone(buf_t bp, int io_offset, int io_size, void (*iodone)(buf_t, void *), v
        }
        io_bp = alloc_io_buf(bp->b_vp, 0);
 
-       io_bp->b_flags = bp->b_flags & (B_COMMIT_UPL | B_META | B_PAGEIO | B_CLUSTER | B_PHYS | B_ASYNC | B_READ);
+       io_bp->b_flags = bp->b_flags & (B_COMMIT_UPL | B_META | B_PAGEIO | B_CLUSTER | B_PHYS | B_RAW | B_ASYNC | B_READ | B_FUA);
 
        if (iodone) {
                io_bp->b_transaction = arg;
@@ -523,19 +751,186 @@ buf_clone(buf_t bp, int io_offset, int io_size, void (*iodone)(buf_t, void *), v
 }
 
 
+int
+buf_shadow(buf_t bp)
+{
+       if (bp->b_lflags & BL_SHADOW)
+               return 1;
+       return 0;
+}
+
+
+buf_t
+buf_create_shadow_priv(buf_t bp, boolean_t force_copy, uintptr_t external_storage, void (*iodone)(buf_t, void *), void *arg)
+{
+       return (buf_create_shadow_internal(bp, force_copy, external_storage, iodone, arg, 1));
+}
+
+buf_t
+buf_create_shadow(buf_t bp, boolean_t force_copy, uintptr_t external_storage, void (*iodone)(buf_t, void *), void *arg)
+{
+       return (buf_create_shadow_internal(bp, force_copy, external_storage, iodone, arg, 0));
+}
+
+
+static buf_t
+buf_create_shadow_internal(buf_t bp, boolean_t force_copy, uintptr_t external_storage, void (*iodone)(buf_t, void *), void *arg, int priv)
+{
+        buf_t  io_bp;
+
+       KERNEL_DEBUG(0xbbbbc000 | DBG_FUNC_START, bp, 0, 0, 0, 0);
+
+       if ( !(bp->b_flags & B_META) || (bp->b_lflags & BL_IOBUF)) {
+
+               KERNEL_DEBUG(0xbbbbc000 | DBG_FUNC_END, bp, 0, 0, 0, 0);
+               return (NULL);
+       }
+#ifdef BUF_MAKE_PRIVATE
+       if (bp->b_shadow_ref && bp->b_data_ref == 0 && external_storage == 0)
+               panic("buf_create_shadow: %p is in the private state (%d, %d)", bp, bp->b_shadow_ref, bp->b_data_ref);
+#endif
+       io_bp = alloc_io_buf(bp->b_vp, priv);
+
+       io_bp->b_flags = bp->b_flags & (B_META | B_ZALLOC | B_ASYNC | B_READ | B_FUA);
+       io_bp->b_blkno = bp->b_blkno;
+       io_bp->b_lblkno = bp->b_lblkno;
+
+       if (iodone) {
+               io_bp->b_transaction = arg;
+               io_bp->b_iodone = iodone;
+               io_bp->b_flags |= B_CALL;
+       }
+       if (force_copy == FALSE) {
+               io_bp->b_bcount = bp->b_bcount;
+               io_bp->b_bufsize = bp->b_bufsize;
+
+               if (external_storage) {
+                       io_bp->b_datap = external_storage;
+#ifdef BUF_MAKE_PRIVATE
+                       io_bp->b_data_store = NULL;
+#endif
+               } else {
+                       io_bp->b_datap = bp->b_datap;
+#ifdef BUF_MAKE_PRIVATE
+                       io_bp->b_data_store = bp;
+#endif
+               }
+               *(buf_t *)(&io_bp->b_orig) = bp;
+
+               lck_mtx_lock_spin(buf_mtxp);
+
+               io_bp->b_lflags |= BL_SHADOW;
+               io_bp->b_shadow = bp->b_shadow;
+               bp->b_shadow = io_bp;
+               bp->b_shadow_ref++;
+
+#ifdef BUF_MAKE_PRIVATE
+               if (external_storage)
+                       io_bp->b_lflags |= BL_EXTERNAL;
+               else
+                       bp->b_data_ref++;
+#endif
+               lck_mtx_unlock(buf_mtxp);
+       } else {
+               if (external_storage) {
+#ifdef BUF_MAKE_PRIVATE
+                       io_bp->b_lflags |= BL_EXTERNAL;
+#endif
+                       io_bp->b_bcount = bp->b_bcount;
+                       io_bp->b_bufsize = bp->b_bufsize;
+                       io_bp->b_datap = external_storage;
+               } else {
+                       allocbuf(io_bp, bp->b_bcount);
+
+                       io_bp->b_lflags |= BL_IOBUF_ALLOC;
+               }
+               bcopy((caddr_t)bp->b_datap, (caddr_t)io_bp->b_datap, bp->b_bcount);
+
+#ifdef BUF_MAKE_PRIVATE
+               io_bp->b_data_store = NULL;
+#endif
+       }
+       KERNEL_DEBUG(0xbbbbc000 | DBG_FUNC_END, bp, bp->b_shadow_ref, 0, io_bp, 0);
+
+       return (io_bp);
+}
+
+
+#ifdef BUF_MAKE_PRIVATE
+errno_t
+buf_make_private(buf_t bp)
+{
+       buf_t   ds_bp;
+       buf_t   t_bp;
+       struct buf my_buf;
+
+       KERNEL_DEBUG(0xbbbbc004 | DBG_FUNC_START, bp, bp->b_shadow_ref, 0, 0, 0);
+
+       if (bp->b_shadow_ref == 0 || bp->b_data_ref == 0 || ISSET(bp->b_lflags, BL_SHADOW)) {
+
+               KERNEL_DEBUG(0xbbbbc004 | DBG_FUNC_END, bp, bp->b_shadow_ref, 0, EINVAL, 0);
+               return (EINVAL);
+       }
+       my_buf.b_flags = B_META;
+       my_buf.b_datap = (uintptr_t)NULL;
+       allocbuf(&my_buf, bp->b_bcount);
+
+       bcopy((caddr_t)bp->b_datap, (caddr_t)my_buf.b_datap, bp->b_bcount);
+
+       lck_mtx_lock_spin(buf_mtxp);
+
+       for (t_bp = bp->b_shadow; t_bp; t_bp = t_bp->b_shadow) {
+               if ( !ISSET(bp->b_lflags, BL_EXTERNAL))
+                       break;
+       }
+       ds_bp = t_bp;
+
+       if (ds_bp == NULL && bp->b_data_ref)
+               panic("buf_make_private: b_data_ref != 0 && ds_bp == NULL");
+
+       if (ds_bp && (bp->b_data_ref == 0 || bp->b_shadow_ref == 0))
+               panic("buf_make_private: ref_count == 0 && ds_bp != NULL");
+
+       if (ds_bp == NULL) {
+               lck_mtx_unlock(buf_mtxp);
+
+               buf_free_meta_store(&my_buf);
+
+               KERNEL_DEBUG(0xbbbbc004 | DBG_FUNC_END, bp, bp->b_shadow_ref, 0, EINVAL, 0);
+               return (EINVAL);
+       }
+       for (t_bp = bp->b_shadow; t_bp; t_bp = t_bp->b_shadow) {
+               if ( !ISSET(t_bp->b_lflags, BL_EXTERNAL))
+                       t_bp->b_data_store = ds_bp;
+       }
+       ds_bp->b_data_ref = bp->b_data_ref;
+
+       bp->b_data_ref = 0;
+       bp->b_datap = my_buf.b_datap;
+
+       lck_mtx_unlock(buf_mtxp);
+
+       KERNEL_DEBUG(0xbbbbc004 | DBG_FUNC_END, bp, bp->b_shadow_ref, 0, 0, 0);
+       return (0);
+}
+#endif
+
 
 void
 buf_setfilter(buf_t bp, void (*filter)(buf_t, void *), void *transaction,
-             void **old_iodone, void **old_transaction)
+                         void (**old_iodone)(buf_t, void *), void **old_transaction)
 {
-        if (old_iodone)
-               *old_iodone = (void *)(bp->b_iodone);
+       if (old_iodone)
+               *old_iodone = bp->b_iodone;
        if (old_transaction)
-               *old_transaction = (void *)(bp->b_transaction);
+               *old_transaction = bp->b_transaction;
 
        bp->b_transaction = transaction;
        bp->b_iodone = filter;
-       bp->b_flags |= B_FILTER;
+       if (filter)
+               bp->b_flags |= B_FILTER;
+       else
+               bp->b_flags &= ~B_FILTER;
 }
 
 
@@ -604,13 +999,13 @@ buf_setfsprivate(buf_t bp, void *fsprivate) {
         bp->b_fsprivate = fsprivate;
 }
 
-ucred_t
+kauth_cred_t
 buf_rcred(buf_t bp) {
 
         return (bp->b_rcred);
 }
 
-ucred_t
+kauth_cred_t
 buf_wcred(buf_t bp) {
 
         return (bp->b_wcred);
@@ -639,7 +1034,7 @@ errno_t
 buf_map(buf_t bp, caddr_t *io_addr)
 {
         buf_t          real_bp;
-       vm_offset_t     vaddr;
+        vm_offset_t    vaddr;
         kern_return_t  kret;
 
         if ( !(bp->b_flags & B_CLUSTER)) {
@@ -662,7 +1057,7 @@ buf_map(buf_t bp, caddr_t *io_addr)
        kret = ubc_upl_map(bp->b_upl, &vaddr);    /* Map it in */
 
        if (kret != KERN_SUCCESS) {
-               *io_addr = 0;
+               *io_addr = NULL;
 
                return(ENOMEM);
        }
@@ -689,8 +1084,13 @@ buf_unmap(buf_t bp)
        if (real_bp && real_bp->b_datap)
                return (0);
 
-       if (bp->b_lflags & BL_IOBUF) {
+       if ((bp->b_lflags & BL_IOBUF) &&
+           ((bp->b_flags & (B_PAGEIO | B_READ)) != (B_PAGEIO | B_READ))) {
                /*
+                * ignore pageins... the 'right' thing will
+                * happen due to the way we handle speculative
+                * clusters...
+                *
                 * when we commit these pages, we'll hit
                 * it with UPL_COMMIT_INACTIVE which
                 * will clear the reference bit that got
@@ -717,8 +1117,6 @@ buf_clear(buf_t bp) {
        bp->b_resid = 0;
 }
 
-
-
 /*
  * Read or write a buffer that is not contiguous on disk.
  * buffer is marked done/error at the conclusion
@@ -776,9 +1174,14 @@ buf_strategy_fragmented(vnode_t devvp, buf_t bp, off_t f_offset, size_t contig_b
                        io_bp->b_blkno   = io_blkno;
 
                        buf_reset(io_bp, io_direction);
+
                        /*
-                        * Call the device to do the I/O and wait for it
+                        * Call the device to do the I/O and wait for it.  Make sure the appropriate party is charged for write
                         */
+
+                       if (!ISSET(bp->b_flags, B_READ))
+                               OSAddAtomic(1, &devvp->v_numoutput);
+
                        if ((error = VNOP_STRATEGY(io_bp)))
                                break;
                        if ((error = (int)buf_biowait(io_bp)))
@@ -825,6 +1228,13 @@ buf_strategy(vnode_t devvp, void *ap)
        vnode_t vp = bp->b_vp;
        int     bmap_flags;
         errno_t error;
+#if CONFIG_DTRACE
+       int dtrace_io_start_flag = 0;    /* We only want to trip the io:::start
+                                         * probe once, with the true physical
+                                         * block in place (b_blkno)
+                                         */
+
+#endif 
 
        if (vp == NULL || vp->v_type == VCHR || vp->v_type == VBLK)
                panic("buf_strategy: b_vp == NULL || vtype == VCHR | VBLK\n");
@@ -849,43 +1259,101 @@ buf_strategy(vnode_t devvp, void *ap)
                         * to deal with filesystem block sizes
                         * that aren't equal to the page size
                         */
+                       DTRACE_IO1(start, buf_t, bp);
                        return (cluster_bp(bp));
                }
                if (bp->b_blkno == bp->b_lblkno) {
-                       off_t   f_offset;
+                   off_t       f_offset;
                        size_t  contig_bytes;
                  
                        if ((error = VNOP_BLKTOOFF(vp, bp->b_lblkno, &f_offset))) {
+                               DTRACE_IO1(start, buf_t, bp);
                                buf_seterror(bp, error);
                                buf_biodone(bp);
 
-                               return (error);
+                           return (error);
                        }
-                       if ((error = VNOP_BLOCKMAP(vp, f_offset, bp->b_bcount, &bp->b_blkno, &contig_bytes, NULL, bmap_flags, NULL))) {
+
+               if ((error = VNOP_BLOCKMAP(vp, f_offset, bp->b_bcount, &bp->b_blkno, &contig_bytes, NULL, bmap_flags, NULL))) {
+                               DTRACE_IO1(start, buf_t, bp);
                                buf_seterror(bp, error);
                                buf_biodone(bp);
 
                                return (error);
                        }
-                       if (bp->b_blkno == -1)
+
+                       DTRACE_IO1(start, buf_t, bp);
+#if CONFIG_DTRACE
+                       dtrace_io_start_flag = 1;
+#endif /* CONFIG_DTRACE */                     
+
+                       if ((bp->b_blkno == -1) || (contig_bytes == 0)) {
+                               /* Set block number to force biodone later */
+                               bp->b_blkno = -1;
                                buf_clear(bp);
-                       else if ((long)contig_bytes < bp->b_bcount)
+                       }
+                       else if ((long)contig_bytes < bp->b_bcount) {
                                return (buf_strategy_fragmented(devvp, bp, f_offset, contig_bytes));
+                       }
+               }
+               
+#if CONFIG_DTRACE
+               if (dtrace_io_start_flag == 0) {
+                       DTRACE_IO1(start, buf_t, bp);
+                       dtrace_io_start_flag = 1;
                }
+#endif /* CONFIG_DTRACE */
+               
                if (bp->b_blkno == -1) {
                        buf_biodone(bp);
                        return (0);
                }
        }
+
+#if CONFIG_DTRACE
+       if (dtrace_io_start_flag == 0)
+               DTRACE_IO1(start, buf_t, bp);
+#endif /* CONFIG_DTRACE */
+       
+#if CONFIG_PROTECT
+       /* Capture f_offset in the bufattr*/
+       if (bp->b_attr.ba_cpentry != 0) {
+               /* No need to go here for older EAs */
+               if(bp->b_attr.ba_cpentry->cp_flags & CP_OFF_IV_ENABLED) {
+                       off_t f_offset;
+                       if ((error = VNOP_BLKTOOFF(bp->b_vp, bp->b_lblkno, &f_offset)))
+                               return error;
+
+                       /* 
+                        * Attach the file offset to this buffer.  The
+                        * bufattr attributes will be passed down the stack
+                        * until they reach IOFlashStorage.  IOFlashStorage
+                        * will retain the offset in a local variable when it
+                        * issues its I/Os to the NAND controller.       
+                        * 
+                        * Note that LwVM may end up splitting this I/O 
+                        * into sub-I/Os if it crosses a chunk boundary.  In this
+                        * case, LwVM will update this field when it dispatches
+                        * each I/O to IOFlashStorage.  But from our perspective
+                        * we have only issued a single I/O.
+                        */
+                       bufattr_setcpoff (&(bp->b_attr), (u_int64_t)f_offset);
+                       CP_DEBUG((CPDBG_OFFSET_IO | DBG_FUNC_NONE), (uint32_t) f_offset, (uint32_t) bp->b_lblkno, (uint32_t) bp->b_blkno, (uint32_t) bp->b_bcount, 0);
+               }
+       }
+#endif
+
        /*
         * we can issue the I/O because...
         * either B_CLUSTER is set which
         * means that the I/O is properly set
         * up to be a multiple of the page size, or
         * we were able to successfully set up the
-        * phsyical block mapping
+        * physical block mapping
         */
-       return (VOCALL(devvp->v_op, VOFFSET(vnop_strategy), ap));
+       error = VOCALL(devvp->v_op, VOFFSET(vnop_strategy), ap);
+       DTRACE_FSINFO(strategy, vnode_t, vp);
+       return (error);
 }
 
 
@@ -903,58 +1371,98 @@ buf_free(buf_t bp) {
 }
 
 
+/*
+ * iterate buffers for the specified vp. 
+ *   if BUF_SCAN_DIRTY is set, do the dirty list
+ *   if BUF_SCAN_CLEAN is set, do the clean list
+ *   if neither flag is set, default to BUF_SCAN_DIRTY
+ *   if BUF_NOTIFY_BUSY is set, call the callout function using a NULL bp for busy pages
+ */
+
+struct buf_iterate_info_t {
+       int flag;
+       struct buflists *listhead;
+};
 
 void
-buf_iterate(vnode_t vp, int (*callout)(buf_t, void *), int flags, void *arg) {
+buf_iterate(vnode_t vp, int (*callout)(buf_t, void *), int flags, void *arg)
+{
        buf_t   bp;
        int     retval;
        struct  buflists local_iterblkhd;
        int     lock_flags = BAC_NOWAIT | BAC_REMOVE;
+       int     notify_busy = flags & BUF_NOTIFY_BUSY;
+       struct buf_iterate_info_t list[2];
+       int     num_lists, i;
 
        if (flags & BUF_SKIP_LOCKED)
                lock_flags |= BAC_SKIP_LOCKED;
        if (flags & BUF_SKIP_NONLOCKED)
                lock_flags |= BAC_SKIP_NONLOCKED;
 
-       lck_mtx_lock(buf_mtxp);
-       
-       if (buf_iterprepare(vp, &local_iterblkhd, VBI_DIRTY))  {
-               lck_mtx_unlock(buf_mtxp);
-               return;
+       if ( !(flags & (BUF_SCAN_DIRTY | BUF_SCAN_CLEAN)))
+               flags |= BUF_SCAN_DIRTY;
+
+       num_lists = 0;
+
+       if (flags & BUF_SCAN_DIRTY) {
+               list[num_lists].flag = VBI_DIRTY;
+               list[num_lists].listhead = &vp->v_dirtyblkhd;
+               num_lists++;
+       }
+       if (flags & BUF_SCAN_CLEAN) {
+               list[num_lists].flag = VBI_CLEAN;
+               list[num_lists].listhead = &vp->v_cleanblkhd;
+               num_lists++;
        }
-       while (!LIST_EMPTY(&local_iterblkhd)) {
-               bp = LIST_FIRST(&local_iterblkhd);
-               LIST_REMOVE(bp, b_vnbufs);
-               LIST_INSERT_HEAD(&vp->v_dirtyblkhd, bp, b_vnbufs);
 
-               if (buf_acquire_locked(bp, lock_flags, 0, 0))
-                       continue;
+       for (i = 0; i < num_lists; i++) {
+               lck_mtx_lock(buf_mtxp);
+       
+               if (buf_iterprepare(vp, &local_iterblkhd, list[i].flag))  {
+                       lck_mtx_unlock(buf_mtxp);
+                       continue;
+               }
+               while (!LIST_EMPTY(&local_iterblkhd)) {
+                       bp = LIST_FIRST(&local_iterblkhd);
+                       LIST_REMOVE(bp, b_vnbufs);
+                       LIST_INSERT_HEAD(list[i].listhead, bp, b_vnbufs);
 
-               lck_mtx_unlock(buf_mtxp);
+                       if (buf_acquire_locked(bp, lock_flags, 0, 0)) {
+                               if (notify_busy) {
+                                       bp = NULL;
+                               } else {
+                                       continue;
+                               }
+                       }
 
-               retval = callout(bp, arg);
+                       lck_mtx_unlock(buf_mtxp);
 
-               switch (retval) {
-               case BUF_RETURNED:
-                       buf_brelse(bp);
-                       break;
-               case BUF_CLAIMED:
-                       break;
-               case BUF_RETURNED_DONE:
-                       buf_brelse(bp);
-                       lck_mtx_lock(buf_mtxp);
-                       goto out;
-               case BUF_CLAIMED_DONE:
-                       lck_mtx_lock(buf_mtxp);
-                       goto out;
-               }
-               lck_mtx_lock(buf_mtxp);
-       }
-out:
-       buf_itercomplete(vp, &local_iterblkhd, VBI_DIRTY);
+                       retval = callout(bp, arg);
 
-       lck_mtx_unlock(buf_mtxp);
-}
+                       switch (retval) {
+                       case BUF_RETURNED:
+                               if (bp)
+                                       buf_brelse(bp);
+                               break;
+                       case BUF_CLAIMED:
+                               break;
+                       case BUF_RETURNED_DONE:
+                               if (bp)
+                                       buf_brelse(bp);
+                               lck_mtx_lock(buf_mtxp);
+                               goto out;
+                       case BUF_CLAIMED_DONE:
+                               lck_mtx_lock(buf_mtxp);
+                               goto out;
+                       }
+                       lck_mtx_lock(buf_mtxp);
+               } /* while list has more nodes */
+         out:
+               buf_itercomplete(vp, &local_iterblkhd, list[i].flag);
+               lck_mtx_unlock(buf_mtxp);
+       } /* for each list */
+} /* buf_iterate */
 
 
 /*
@@ -964,10 +1472,15 @@ int
 buf_invalidateblks(vnode_t vp, int flags, int slpflag, int slptimeo)
 {
        buf_t   bp;
+       int     aflags;
        int     error = 0;
        int     must_rescan = 1;
        struct  buflists local_iterblkhd;
 
+
+       if (LIST_EMPTY(&vp->v_cleanblkhd) && LIST_EMPTY(&vp->v_dirtyblkhd))
+               return (0);
+
        lck_mtx_lock(buf_mtxp);
 
        for (;;) {
@@ -990,6 +1503,7 @@ buf_invalidateblks(vnode_t vp, int flags, int slpflag, int slptimeo)
                        goto try_dirty_list;
                }
                while (!LIST_EMPTY(&local_iterblkhd)) {
+
                        bp = LIST_FIRST(&local_iterblkhd);
 
                        LIST_REMOVE(bp, b_vnbufs);
@@ -1001,7 +1515,12 @@ buf_invalidateblks(vnode_t vp, int flags, int slpflag, int slptimeo)
                        if ((flags & BUF_SKIP_META) && (bp->b_lblkno < 0 || ISSET(bp->b_flags, B_META)))
                                continue;
 
-                       if ( (error = (int)buf_acquire_locked(bp, BAC_REMOVE | BAC_SKIP_LOCKED, slpflag, slptimeo)) ) {
+                       aflags = BAC_REMOVE;
+
+                       if ( !(flags & BUF_INVALIDATE_LOCKED) )
+                               aflags |= BAC_SKIP_LOCKED;
+
+                       if ( (error = (int)buf_acquire_locked(bp, aflags, slpflag, slptimeo)) ) {
                                if (error == EDEADLK)
                                        /*      
                                         * this buffer was marked B_LOCKED... 
@@ -1029,6 +1548,10 @@ buf_invalidateblks(vnode_t vp, int flags, int slpflag, int slptimeo)
                        }
                        lck_mtx_unlock(buf_mtxp);
 
+                       if (bp->b_flags & B_LOCKED)
+                               KERNEL_DEBUG(0xbbbbc038, bp, 0, 0, 0, 0);
+
+                       CLR(bp->b_flags, B_LOCKED);
                        SET(bp->b_flags, B_INVAL);
                        buf_brelse(bp);
 
@@ -1063,7 +1586,12 @@ try_dirty_list:
                        if ((flags & BUF_SKIP_META) && (bp->b_lblkno < 0 || ISSET(bp->b_flags, B_META)))
                                continue;
 
-                       if ( (error = (int)buf_acquire_locked(bp, BAC_REMOVE | BAC_SKIP_LOCKED, slpflag, slptimeo)) ) {
+                       aflags = BAC_REMOVE;
+
+                       if ( !(flags & BUF_INVALIDATE_LOCKED) )
+                               aflags |= BAC_SKIP_LOCKED;
+
+                       if ( (error = (int)buf_acquire_locked(bp, aflags, slpflag, slptimeo)) ) {
                                if (error == EDEADLK)
                                        /*      
                                         * this buffer was marked B_LOCKED... 
@@ -1091,6 +1619,10 @@ try_dirty_list:
                        }
                        lck_mtx_unlock(buf_mtxp);
 
+                       if (bp->b_flags & B_LOCKED)
+                               KERNEL_DEBUG(0xbbbbc038, bp, 0, 0, 1, 0);
+
+                       CLR(bp->b_flags, B_LOCKED);
                        SET(bp->b_flags, B_INVAL);
 
                        if (ISSET(bp->b_flags, B_DELWRI) && (flags & BUF_WRITE_DATA))
@@ -1115,13 +1647,21 @@ try_dirty_list:
 }
 
 void
-buf_flushdirtyblks(vnode_t vp, int wait, int flags, char *msg) {
+buf_flushdirtyblks(vnode_t vp, int wait, int flags, const char *msg) {
+
+       (void) buf_flushdirtyblks_skipinfo(vp, wait, flags, msg);
+       return;
+}
+
+int
+buf_flushdirtyblks_skipinfo(vnode_t vp, int wait, int flags, const char *msg) {
        buf_t   bp;
        int     writes_issued = 0;
        errno_t error;
        int     busy = 0;
        struct  buflists local_iterblkhd;
        int     lock_flags = BAC_NOWAIT | BAC_REMOVE;
+       int any_locked = 0;
 
        if (flags & BUF_SKIP_LOCKED)
                lock_flags |= BAC_SKIP_LOCKED;
@@ -1135,11 +1675,26 @@ loop:
                        bp = LIST_FIRST(&local_iterblkhd);
                        LIST_REMOVE(bp, b_vnbufs);
                        LIST_INSERT_HEAD(&vp->v_dirtyblkhd, bp, b_vnbufs);
-                       
-                       if ((error = buf_acquire_locked(bp, lock_flags, 0, 0)) == EBUSY)
-                               busy++;
-                       if (error)
-                               continue;
+
+                       if ((error = buf_acquire_locked(bp, lock_flags, 0, 0)) == EBUSY) {
+                               busy++;
+                       }
+                       if (error) {
+                               /* 
+                                * If we passed in BUF_SKIP_LOCKED or BUF_SKIP_NONLOCKED,
+                                * we may want to do somethign differently if a locked or unlocked
+                                * buffer was encountered (depending on the arg specified).
+                                * In this case, we know that one of those two was set, and the
+                                * buf acquisition failed above.  
+                                * 
+                                * If it failed with EDEADLK, then save state which can be emitted
+                                * later on to the caller.  Most callers should not care.
+                                */
+                               if (error == EDEADLK) {
+                                       any_locked++;
+                               }
+                               continue;
+                       }
                        lck_mtx_unlock(buf_mtxp);
 
                        bp->b_flags &= ~B_LOCKED;
@@ -1185,6 +1740,8 @@ loop:
                        goto loop;
                }
        }
+
+       return any_locked;
 }
 
 
@@ -1204,7 +1761,7 @@ buf_iterprepare(vnode_t vp, struct buflists *iterheadp, int flags)
                
        while (vp->v_iterblkflags & VBI_ITER)   {
                vp->v_iterblkflags |= VBI_ITERWANT;
-               msleep(&vp->v_iterblkflags, buf_mtxp, 0, "buf_iterprepare", 0); 
+               msleep(&vp->v_iterblkflags, buf_mtxp, 0, "buf_iterprepare", NULL);      
        }
        if (LIST_EMPTY(listheadp)) {
                LIST_INIT(iterheadp);
@@ -1252,8 +1809,20 @@ static void
 bremfree_locked(buf_t bp)
 {
        struct bqueues *dp = NULL;
-       int whichq = -1;
+       int whichq;
+
+       whichq = bp->b_whichq;
 
+       if (whichq == -1) {
+               if (bp->b_shadow_ref == 0)
+                       panic("bremfree_locked: %p not on freelist", bp);
+               /*
+                * there are clones pointing to 'bp'...
+                * therefore, it was not put on a freelist
+                * when buf_brelse was last called on 'bp'
+                */
+               return;
+       }
        /*
         * We only calculate the head of the freelist when removing
         * the last element of the list as that is the only time that
@@ -1262,30 +1831,31 @@ bremfree_locked(buf_t bp)
         * NB: This makes an assumption about how tailq's are implemented.
         */
        if (bp->b_freelist.tqe_next == NULL) {
-               for (dp = bufqueues; dp < &bufqueues[BQUEUES]; dp++)
-                       if (dp->tqh_last == &bp->b_freelist.tqe_next)
-                               break;
-               if (dp == &bufqueues[BQUEUES])
+               dp = &bufqueues[whichq];
+
+               if (dp->tqh_last != &bp->b_freelist.tqe_next)
                        panic("bremfree: lost tail");
        }
        TAILQ_REMOVE(dp, bp, b_freelist);
-       whichq = bp->b_whichq;
-#if BALANCE_QUEUES
-       bufqdec(whichq);
-#endif
+
+       if (whichq == BQ_LAUNDRY)
+               blaundrycnt--;
+
        bp->b_whichq = -1;
        bp->b_timestamp = 0; 
+       bp->b_shadow = 0;
 }
 
 /*
  * Associate a buffer with a vnode.
+ * buf_mtxp must be locked on entry
  */
 static void
-bgetvp(vnode_t vp, buf_t bp)
+bgetvp_locked(vnode_t vp, buf_t bp)
 {
 
        if (bp->b_vp != vp)
-               panic("bgetvp: not free");
+               panic("bgetvp_locked: not free");
 
        if (vp->v_type == VBLK || vp->v_type == VCHR)
                bp->b_dev = vp->v_rdev;
@@ -1294,28 +1864,21 @@ bgetvp(vnode_t vp, buf_t bp)
        /*
         * Insert onto list for new vnode.
         */
-       lck_mtx_lock(buf_mtxp);
        bufinsvn(bp, &vp->v_cleanblkhd);
-       lck_mtx_unlock(buf_mtxp);
 }
 
 /*
  * Disassociate a buffer from a vnode.
+ * buf_mtxp must be locked on entry
  */
 static void
-brelvp(buf_t bp)
+brelvp_locked(buf_t bp)
 {
-       vnode_t vp;
-
-       if ((vp = bp->b_vp) == (vnode_t)NULL)
-               panic("brelvp: NULL vp");
        /*
         * Delete from old vnode list, if on one.
         */
-       lck_mtx_lock(buf_mtxp);
        if (bp->b_vnbufs.le_next != NOLIST)
                bufremvn(bp);
-       lck_mtx_unlock(buf_mtxp);
 
        bp->b_vp = (vnode_t)NULL;
 }
@@ -1328,13 +1891,13 @@ brelvp(buf_t bp)
 static void
 buf_reassign(buf_t bp, vnode_t newvp)
 {
-       register struct buflists *listheadp;
+       struct buflists *listheadp;
 
        if (newvp == NULL) {
                printf("buf_reassign: NULL");
                return;
        }
-       lck_mtx_lock(buf_mtxp);
+       lck_mtx_lock_spin(buf_mtxp);
 
        /*
         * Delete from old vnode list, if on one.
@@ -1371,59 +1934,55 @@ bufhdrinit(buf_t bp)
  * Initialize buffers and hash links for buffers.
  */
 __private_extern__ void
-bufinit()
+bufinit(void)
 {
        buf_t   bp;
        struct bqueues *dp;
        int     i;
-       int     metabuf;
-       long    whichq;
 
+       nbuf_headers = 0;
        /* Initialize the buffer queues ('freelists') and the hash table */
        for (dp = bufqueues; dp < &bufqueues[BQUEUES]; dp++)
                TAILQ_INIT(dp);
-       bufhashtbl = hashinit(nbuf, M_CACHE, &bufhash);
+       bufhashtbl = hashinit(nbuf_hashelements, M_CACHE, &bufhash);
 
-       metabuf = nbuf/8; /* reserved for meta buf */
+       buf_busycount = 0;
 
        /* Initialize the buffer headers */
-       for (i = 0; i < nbuf; i++) {
-               bp = &buf[i];
+       for (i = 0; i < max_nbuf_headers; i++) {
+               nbuf_headers++;
+               bp = &buf_headers[i];
                bufhdrinit(bp);
 
-               /*
-                * metabuf buffer headers on the meta-data list and
-                * rest of the buffer headers on the empty list
-                */
-               if (--metabuf) 
-                       whichq = BQ_META;
-               else 
-                       whichq = BQ_EMPTY;
-
                BLISTNONE(bp);
-               dp = &bufqueues[whichq];
-               binsheadfree(bp, dp, whichq);
+               dp = &bufqueues[BQ_EMPTY];
+               bp->b_whichq = BQ_EMPTY;
+               bp->b_timestamp = buf_timestamp();
+               binsheadfree(bp, dp, BQ_EMPTY);
                binshash(bp, &invalhash);
        }
+       boot_nbuf_headers = nbuf_headers;
 
-       for (; i < nbuf + niobuf; i++) {
-               bp = &buf[i];
+       TAILQ_INIT(&iobufqueue);
+       TAILQ_INIT(&delaybufqueue);
+
+       for (; i < nbuf_headers + niobuf_headers; i++) {
+               bp = &buf_headers[i];
                bufhdrinit(bp);
+               bp->b_whichq = -1;
                binsheadfree(bp, &iobufqueue, -1);
        }
 
-        /*
+       /*
         * allocate lock group attribute and group
         */
-        buf_mtx_grp_attr = lck_grp_attr_alloc_init();
-       //lck_grp_attr_setstat(buf_mtx_grp_attr);
+       buf_mtx_grp_attr = lck_grp_attr_alloc_init();
        buf_mtx_grp = lck_grp_alloc_init("buffer cache", buf_mtx_grp_attr);
                
        /*
         * allocate the lock attribute
         */
        buf_mtx_attr = lck_attr_alloc_init();
-       //lck_attr_setdebug(buf_mtx_attr);
 
        /*
         * allocate and initialize mutex's for the buffer and iobuffer pools
@@ -1443,7 +2002,7 @@ bufinit()
        cluster_init();
 
        printf("using %d buffer headers and %d cluster IO buffer headers\n",
-               nbuf, niobuf);
+               nbuf_headers, niobuf_headers);
 
        /* Set up zones used by the buffer cache */
        bufzoneinit();
@@ -1451,17 +2010,76 @@ bufinit()
        /* start the bcleanbuf() thread */
        bcleanbuf_thread_init();
 
-#if BALANCE_QUEUES
-       {
-       static void bufq_balance_thread_init();
-       /* create a thread to do dynamic buffer queue balancing */
-       bufq_balance_thread_init();
+       /* Register a callout for relieving vm pressure */
+       if (vm_set_buffer_cleanup_callout(buffer_cache_gc) != KERN_SUCCESS) {
+               panic("Couldn't register buffer cache callout for vm pressure!\n");
+       }
+
+}
+
+/*
+ * Zones for the meta data buffers
+ */
+
+#define MINMETA 512
+#define MAXMETA 8192
+
+struct meta_zone_entry {
+       zone_t mz_zone;
+       vm_size_t mz_size;
+       vm_size_t mz_max;
+       const char *mz_name;
+};
+
+struct meta_zone_entry meta_zones[] = {
+       {NULL, (MINMETA * 1), 128 * (MINMETA * 1), "buf.512" },
+       {NULL, (MINMETA * 2),  64 * (MINMETA * 2), "buf.1024" },
+       {NULL, (MINMETA * 4),  16 * (MINMETA * 4), "buf.2048" },
+       {NULL, (MINMETA * 8), 512 * (MINMETA * 8), "buf.4096" },
+       {NULL, (MINMETA * 16), 512 * (MINMETA * 16), "buf.8192" },
+       {NULL, 0, 0, "" } /* End */
+};
+
+/*
+ * Initialize the meta data zones
+ */
+static void
+bufzoneinit(void)
+{
+       int i;
+
+       for (i = 0; meta_zones[i].mz_size != 0; i++) {
+               meta_zones[i].mz_zone = 
+                               zinit(meta_zones[i].mz_size,
+                                       meta_zones[i].mz_max,
+                                       PAGE_SIZE,
+                                       meta_zones[i].mz_name);
+               zone_change(meta_zones[i].mz_zone, Z_CALLERACCT, FALSE);
+       }
+       buf_hdr_zone = zinit(sizeof(struct buf), 32, PAGE_SIZE, "buf headers");
+       zone_change(buf_hdr_zone, Z_CALLERACCT, FALSE);
+}
+
+static __inline__ zone_t
+getbufzone(size_t size)
+{
+       int i;
+
+       if ((size % 512) || (size < MINMETA) || (size > MAXMETA))
+               panic("getbufzone: incorect size = %lu", size);
+
+       for (i = 0; meta_zones[i].mz_size != 0; i++) {
+               if (meta_zones[i].mz_size >= size)
+                       break;
        }
-#endif /* notyet */
+
+       return (meta_zones[i].mz_zone);
 }
 
+
+
 static struct buf *
-bio_doread(vnode_t vp, daddr64_t blkno, int size, ucred_t cred, int async, int queuetype)
+bio_doread(vnode_t vp, daddr64_t blkno, int size, kauth_cred_t cred, int async, int queuetype)
 {
        buf_t   bp;
 
@@ -1479,7 +2097,7 @@ bio_doread(vnode_t vp, daddr64_t blkno, int size, ucred_t cred, int async, int q
 
                /* Start I/O for the buffer (keeping credentials). */
                SET(bp->b_flags, B_READ | async);
-               if (cred != NOCRED && bp->b_rcred == NOCRED) {
+               if (IS_VALID_CRED(cred) && !IS_VALID_CRED(bp->b_rcred)) {
                        kauth_cred_ref(cred);
                        bp->b_rcred = cred;
                }
@@ -1489,8 +2107,9 @@ bio_doread(vnode_t vp, daddr64_t blkno, int size, ucred_t cred, int async, int q
                trace(TR_BREADMISS, pack(vp, size), blkno);
 
                /* Pay for the read. */
-               if (p && p->p_stats) 
-                       p->p_stats->p_ru.ru_inblock++;          /* XXX */
+               if (p && p->p_stats) { 
+                       OSIncrementAtomicLong(&p->p_stats->p_ru.ru_inblock);            /* XXX */
+               }
 
                if (async) {
                        /*
@@ -1517,7 +2136,7 @@ bio_doread(vnode_t vp, daddr64_t blkno, int size, ucred_t cred, int async, int q
  */
 static errno_t
 do_breadn_for_type(vnode_t vp, daddr64_t blkno, int size, daddr64_t *rablks, int *rasizes, 
-                  int nrablks, ucred_t cred, buf_t *bpp, int queuetype)
+                  int nrablks, kauth_cred_t cred, buf_t *bpp, int queuetype)
 {
        buf_t   bp;
        int     i;
@@ -1546,7 +2165,7 @@ do_breadn_for_type(vnode_t vp, daddr64_t blkno, int size, daddr64_t *rablks, int
  * This algorithm described in Bach (p.54).
  */
 errno_t
-buf_bread(vnode_t vp, daddr64_t blkno, int size, ucred_t cred, buf_t *bpp)
+buf_bread(vnode_t vp, daddr64_t blkno, int size, kauth_cred_t cred, buf_t *bpp)
 {
        buf_t   bp;
 
@@ -1562,7 +2181,7 @@ buf_bread(vnode_t vp, daddr64_t blkno, int size, ucred_t cred, buf_t *bpp)
  * This algorithm described in Bach (p.54).
  */
 errno_t
-buf_meta_bread(vnode_t vp, daddr64_t blkno, int size, ucred_t cred, buf_t *bpp)
+buf_meta_bread(vnode_t vp, daddr64_t blkno, int size, kauth_cred_t cred, buf_t *bpp)
 {
        buf_t   bp;
 
@@ -1577,7 +2196,7 @@ buf_meta_bread(vnode_t vp, daddr64_t blkno, int size, ucred_t cred, buf_t *bpp)
  * Read-ahead multiple disk blocks. The first is sync, the rest async.
  */
 errno_t
-buf_breadn(vnode_t vp, daddr64_t blkno, int size, daddr64_t *rablks, int *rasizes, int nrablks, ucred_t cred, buf_t *bpp)
+buf_breadn(vnode_t vp, daddr64_t blkno, int size, daddr64_t *rablks, int *rasizes, int nrablks, kauth_cred_t cred, buf_t *bpp)
 {
        return (do_breadn_for_type(vp, blkno, size, rablks, rasizes, nrablks, cred, bpp, BLK_READ));
 }
@@ -1587,7 +2206,7 @@ buf_breadn(vnode_t vp, daddr64_t blkno, int size, daddr64_t *rablks, int *rasize
  * [buf_breadn() for meta-data]
  */
 errno_t
-buf_meta_breadn(vnode_t vp, daddr64_t blkno, int size, daddr64_t *rablks, int *rasizes, int nrablks, ucred_t cred, buf_t *bpp)
+buf_meta_breadn(vnode_t vp, daddr64_t blkno, int size, daddr64_t *rablks, int *rasizes, int nrablks, kauth_cred_t cred, buf_t *bpp)
 {
        return (do_breadn_for_type(vp, blkno, size, rablks, rasizes, nrablks, cred, bpp, BLK_META));
 }
@@ -1613,7 +2232,7 @@ buf_bwrite(buf_t bp)
        CLR(bp->b_flags, (B_READ | B_DONE | B_ERROR | B_DELWRI));
 
        if (wasdelayed)
-               OSAddAtomic(-1, &nbdwrite);
+               OSAddAtomicLong(-1, &nbdwrite);
 
        if (!sync) {
                /*
@@ -1624,9 +2243,10 @@ buf_bwrite(buf_t bp)
                 */
                if (wasdelayed)
                        buf_reassign(bp, vp);
-               else
-               if (p && p->p_stats) 
-                       p->p_stats->p_ru.ru_oublock++;          /* XXX */
+               else 
+                       if (p && p->p_stats) {
+                               OSIncrementAtomicLong(&p->p_stats->p_ru.ru_oublock);    /* XXX */
+                       }
        }
        trace(TR_BUFWRITE, pack(vp, bp->b_bcount), bp->b_lblkno);
 
@@ -1650,8 +2270,9 @@ buf_bwrite(buf_t bp)
                if (wasdelayed)
                        buf_reassign(bp, vp);
                else
-               if (p && p->p_stats) 
-                       p->p_stats->p_ru.ru_oublock++;          /* XXX */
+                       if (p && p->p_stats) { 
+                               OSIncrementAtomicLong(&p->p_stats->p_ru.ru_oublock);    /* XXX */
+                       }
 
                /* Release the buffer. */
                // XXXdbg - only if the unused bit is set
@@ -1668,8 +2289,7 @@ buf_bwrite(buf_t bp)
 }
 
 int
-vn_bwrite(ap)
-       struct vnop_bwrite_args *ap;
+vn_bwrite(struct vnop_bwrite_args *ap)
 {
        return (buf_bwrite(ap->a_bp));
 }
@@ -1687,11 +2307,11 @@ vn_bwrite(ap)
  *
  * Described in Leffler, et al. (pp. 208-213).
  *
- * Note: With the abilitty to allocate additional buffer
+ * Note: With the ability to allocate additional buffer
  * headers, we can get in to the situation where "too" many 
  * buf_bdwrite()s can create situation where the kernel can create
  * buffers faster than the disks can service. Doing a buf_bawrite() in
- * cases were we have "too many" outstanding buf_bdwrite()s avoids that.
+ * cases where we have "too many" outstanding buf_bdwrite()s avoids that.
  */
 __private_extern__ int
 bdwrite_internal(buf_t bp, int return_error)
@@ -1707,18 +2327,13 @@ bdwrite_internal(buf_t bp, int return_error)
         */
        if (!ISSET(bp->b_flags, B_DELWRI)) {
                SET(bp->b_flags, B_DELWRI);
-               if (p && p->p_stats) 
-                       p->p_stats->p_ru.ru_oublock++;          /* XXX */
-               OSAddAtomic(1, &nbdwrite);
+               if (p && p->p_stats) { 
+                       OSIncrementAtomicLong(&p->p_stats->p_ru.ru_oublock);    /* XXX */
+               }
+               OSAddAtomicLong(1, &nbdwrite);
                buf_reassign(bp, vp);
        }
 
-       /* If this is a tape block, write it the block now. */
-       if (ISSET(bp->b_flags, B_TAPE)) {
-               VNOP_BWRITE(bp);
-               return (0);
-       }
-
        /*
         * if we're not LOCKED, but the total number of delayed writes
         * has climbed above 75% of the total buffers in the system
@@ -1733,14 +2348,14 @@ bdwrite_internal(buf_t bp, int return_error)
         * buffer is part of a transaction and can't go to disk until
         * the LOCKED bit is cleared.
         */
-       if (!ISSET(bp->b_flags, B_LOCKED) && nbdwrite > ((nbuf/4)*3)) {
+       if (!ISSET(bp->b_flags, B_LOCKED) && nbdwrite > ((nbuf_headers/4)*3)) {
                if (return_error)
                        return (EAGAIN);
                /*
                 * If the vnode has "too many" write operations in progress
                 * wait for them to finish the IO
                 */
-               (void)vnode_waitforwrites(vp, VNODE_ASYNC_THROTTLE, 0, 0, (char *)"buf_bdwrite");
+               (void)vnode_waitforwrites(vp, VNODE_ASYNC_THROTTLE, 0, 0, "buf_bdwrite");
 
                return (buf_bawrite(bp));
        }
@@ -1799,6 +2414,126 @@ buf_bawrite(buf_t bp)
 }
 
 
+
+static void
+buf_free_meta_store(buf_t bp)
+{
+       if (bp->b_bufsize) {
+               if (ISSET(bp->b_flags, B_ZALLOC)) {
+                       zone_t z;
+
+                       z = getbufzone(bp->b_bufsize);
+                       zfree(z, (void *)bp->b_datap);
+               } else
+                       kmem_free(kernel_map, bp->b_datap, bp->b_bufsize); 
+
+               bp->b_datap = (uintptr_t)NULL;
+               bp->b_bufsize = 0;
+       }
+}
+
+
+static buf_t
+buf_brelse_shadow(buf_t bp)
+{
+       buf_t   bp_head;
+       buf_t   bp_temp;
+       buf_t   bp_return = NULL;
+#ifdef BUF_MAKE_PRIVATE
+       buf_t   bp_data;
+       int     data_ref = 0;
+#endif
+       int need_wakeup = 0;
+
+       lck_mtx_lock_spin(buf_mtxp);
+
+       bp_head = (buf_t)bp->b_orig;
+
+       if (bp_head->b_whichq != -1)
+               panic("buf_brelse_shadow: bp_head on freelist %d\n", bp_head->b_whichq);
+
+#ifdef BUF_MAKE_PRIVATE
+       if (bp_data = bp->b_data_store) {
+               bp_data->b_data_ref--;
+               /*
+                * snapshot the ref count so that we can check it 
+                * outside of the lock... we only want the guy going
+                * from 1 -> 0 to try and release the storage
+                */
+               data_ref = bp_data->b_data_ref;
+       }
+#endif
+       KERNEL_DEBUG(0xbbbbc008 | DBG_FUNC_START, bp, bp_head, bp_head->b_shadow_ref, 0, 0);
+
+       bp_head->b_shadow_ref--;
+
+       for (bp_temp = bp_head; bp_temp && bp != bp_temp->b_shadow; bp_temp = bp_temp->b_shadow);
+
+       if (bp_temp == NULL)
+               panic("buf_brelse_shadow: bp not on list %p", bp_head);
+
+       bp_temp->b_shadow = bp_temp->b_shadow->b_shadow;
+
+#ifdef BUF_MAKE_PRIVATE
+       /*
+        * we're about to free the current 'owner' of the data buffer and
+        * there is at least one other shadow buf_t still pointing at it
+        * so transfer it to the first shadow buf left in the chain
+        */
+       if (bp == bp_data && data_ref) {
+               if ((bp_data = bp_head->b_shadow) == NULL)
+                       panic("buf_brelse_shadow: data_ref mismatch bp(%p)", bp);
+
+               for (bp_temp = bp_data; bp_temp; bp_temp = bp_temp->b_shadow)
+                       bp_temp->b_data_store = bp_data;
+               bp_data->b_data_ref = data_ref;
+       }
+#endif
+       if (bp_head->b_shadow_ref == 0 && bp_head->b_shadow)
+               panic("buf_relse_shadow: b_shadow != NULL && b_shadow_ref == 0  bp(%p)", bp); 
+       if (bp_head->b_shadow_ref && bp_head->b_shadow == 0)
+               panic("buf_relse_shadow: b_shadow == NULL && b_shadow_ref != 0  bp(%p)", bp); 
+
+       if (bp_head->b_shadow_ref == 0) {
+               if (!ISSET(bp_head->b_lflags, BL_BUSY)) {
+
+                       CLR(bp_head->b_flags, B_AGE);
+                       bp_head->b_timestamp = buf_timestamp();
+
+                       if (ISSET(bp_head->b_flags, B_LOCKED)) {
+                               bp_head->b_whichq = BQ_LOCKED;
+                               binstailfree(bp_head, &bufqueues[BQ_LOCKED], BQ_LOCKED);
+                       } else {
+                               bp_head->b_whichq = BQ_META;
+                               binstailfree(bp_head, &bufqueues[BQ_META], BQ_META);
+                       }
+               } else if (ISSET(bp_head->b_lflags, BL_WAITSHADOW)) {
+                       CLR(bp_head->b_lflags, BL_WAITSHADOW);
+
+                       bp_return = bp_head;
+               }
+               if (ISSET(bp_head->b_lflags, BL_WANTED_REF)) {
+                       CLR(bp_head->b_lflags, BL_WANTED_REF);
+                       need_wakeup = 1;
+               }
+       }
+       lck_mtx_unlock(buf_mtxp);
+
+       if (need_wakeup)
+               wakeup(bp_head);
+
+#ifdef BUF_MAKE_PRIVATE        
+       if (bp == bp_data && data_ref == 0)
+               buf_free_meta_store(bp);
+
+       bp->b_data_store = NULL;
+#endif
+       KERNEL_DEBUG(0xbbbbc008 | DBG_FUNC_END, bp, 0, 0, 0, 0);
+
+       return (bp_return);
+}
+
+
 /*
  * Release a buffer on to the free lists.
  * Described in Bach (p. 46).
@@ -1814,26 +2549,32 @@ buf_brelse(buf_t bp)
 
 
        if (bp->b_whichq != -1 || !(bp->b_lflags & BL_BUSY))
-               panic("buf_brelse: bad buffer = %x\n", bp);
+               panic("buf_brelse: bad buffer = %p\n", bp);
 
 #ifdef JOE_DEBUG
-       bp->b_stackbrelse[0] = __builtin_return_address(0);
-       bp->b_stackbrelse[1] = __builtin_return_address(1);
-       bp->b_stackbrelse[2] = __builtin_return_address(2);
-       bp->b_stackbrelse[3] = __builtin_return_address(3);
-       bp->b_stackbrelse[4] = __builtin_return_address(4);
-       bp->b_stackbrelse[5] = __builtin_return_address(5);
+       (void) OSBacktrace(&bp->b_stackbrelse[0], 6);
 
        bp->b_lastbrelse = current_thread();
        bp->b_tag = 0;
 #endif
        if (bp->b_lflags & BL_IOBUF) {
+               buf_t   shadow_master_bp = NULL;
+
+               if (ISSET(bp->b_lflags, BL_SHADOW))
+                       shadow_master_bp = buf_brelse_shadow(bp);
+               else if (ISSET(bp->b_lflags, BL_IOBUF_ALLOC))
+                        buf_free_meta_store(bp);
                free_io_buf(bp);
+
+               if (shadow_master_bp) {
+                       bp = shadow_master_bp;
+                       goto finish_shadow_master;
+               }
                return;
        }
 
        KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 388)) | DBG_FUNC_START,
-                    bp->b_lblkno * PAGE_SIZE, (int)bp, (int)bp->b_datap,
+                    bp->b_lblkno * PAGE_SIZE, bp, bp->b_datap,
                     bp->b_flags, 0);
 
        trace(TR_BRELSE, pack(bp->b_vp, bp->b_bufsize), bp->b_lblkno);
@@ -1848,14 +2589,14 @@ buf_brelse(buf_t bp)
        if (ISSET(bp->b_flags, B_META) && ISSET(bp->b_flags, B_INVAL)) {
                if (ISSET(bp->b_flags, B_FILTER)) {     /* if necessary, call out */
                        void    (*iodone_func)(struct buf *, void *) = bp->b_iodone;
-                       void    *arg = (void *)bp->b_transaction;
+                       void    *arg = bp->b_transaction;
 
                        CLR(bp->b_flags, B_FILTER);     /* but note callout done */
                        bp->b_iodone = NULL;
                        bp->b_transaction = NULL;
 
                        if (iodone_func == NULL) {
-                               panic("brelse: bp @ 0x%x has NULL b_iodone!\n", bp);
+                               panic("brelse: bp @ %p has NULL b_iodone!\n", bp);
                        }
                        (*iodone_func)(bp, arg);
                }
@@ -1869,7 +2610,7 @@ buf_brelse(buf_t bp)
                kern_return_t kret;
                int           upl_flags;
 
-               if ( (upl == NULL) ) {
+               if (upl == NULL) {
                        if ( !ISSET(bp->b_flags, B_INVAL)) {
                                kret = ubc_create_upl(bp->b_vp, 
                                                      ubc_blktooff(bp->b_vp, bp->b_lblkno),
@@ -1880,8 +2621,8 @@ buf_brelse(buf_t bp)
 
                                if (kret != KERN_SUCCESS)
                                        panic("brelse: Failed to create UPL");
-#ifdef  UPL_DEBUG
-                               upl_ubc_alias_set(upl, bp, 5);
+#if  UPL_DEBUG
+                               upl_ubc_alias_set(upl, (uintptr_t) bp, (uintptr_t) 5);
 #endif /* UPL_DEBUG */
                        }
                } else {
@@ -1914,7 +2655,7 @@ buf_brelse(buf_t bp)
                }
        } else {
                if ( (upl) )
-                       panic("brelse: UPL set for non VREG; vp=%x", bp->b_vp);
+                       panic("brelse: UPL set for non VREG; vp=%p", bp->b_vp);
        }       
 
        /*
@@ -1928,33 +2669,61 @@ buf_brelse(buf_t bp)
        if (ISSET(bp->b_flags, (B_NOCACHE|B_ERROR)))
                SET(bp->b_flags, B_INVAL);
        
-       if ((bp->b_bufsize <= 0) || ISSET(bp->b_flags, B_INVAL)) {
+       if ((bp->b_bufsize <= 0) || 
+                       ISSET(bp->b_flags, B_INVAL) || 
+                       (ISSET(bp->b_lflags, BL_WANTDEALLOC) && !ISSET(bp->b_flags, B_DELWRI))) {
+
+               boolean_t       delayed_buf_free_meta_store = FALSE;
+
                /*
-                * If it's invalid or empty, dissociate it from its vnode
-                * and put on the head of the appropriate queue.
+                * If it's invalid or empty, dissociate it from its vnode,
+                * release its storage if B_META, and
+                * clean it up a bit and put it on the EMPTY queue
                 */
-               if (bp->b_vp)
-                       brelvp(bp);
-
                if (ISSET(bp->b_flags, B_DELWRI))
-                       OSAddAtomic(-1, &nbdwrite);
+                       OSAddAtomicLong(-1, &nbdwrite);
 
-               CLR(bp->b_flags, (B_DELWRI | B_LOCKED | B_AGE | B_ASYNC | B_NOCACHE));
+               if (ISSET(bp->b_flags, B_META)) {
+                       if (bp->b_shadow_ref)
+                               delayed_buf_free_meta_store = TRUE;
+                       else
+                               buf_free_meta_store(bp);
+               }
                /*
-                * Determine which queue the buffer should be on, then put it there.
+                * nuke any credentials we were holding
                 */
-               if (bp->b_bufsize <= 0)
-                       whichq = BQ_EMPTY;      /* no data */
-               else if (ISSET(bp->b_flags, B_META))
-                       whichq = BQ_META;               /* meta-data */
-               else
-                       whichq = BQ_AGE;        /* invalid data */
-               bufq = &bufqueues[whichq];
+               buf_release_credentials(bp);
 
-               lck_mtx_lock(buf_mtxp);
+               lck_mtx_lock_spin(buf_mtxp);
+
+               if (bp->b_shadow_ref) {
+                       SET(bp->b_lflags, BL_WAITSHADOW);
+                       
+                       lck_mtx_unlock(buf_mtxp);
+                       
+                       return;
+               }
+               if (delayed_buf_free_meta_store == TRUE) {
+
+                       lck_mtx_unlock(buf_mtxp);
+finish_shadow_master:
+                       buf_free_meta_store(bp);
+
+                       lck_mtx_lock_spin(buf_mtxp);
+               }
+               CLR(bp->b_flags, (B_META | B_ZALLOC | B_DELWRI | B_LOCKED | B_AGE | B_ASYNC | B_NOCACHE | B_FUA));
+
+               if (bp->b_vp)
+                       brelvp_locked(bp);
 
-               binsheadfree(bp, bufq, whichq);
+               bremhash(bp);
+               BLISTNONE(bp);
+               binshash(bp, &invalhash);
+
+               bp->b_whichq = BQ_EMPTY;
+               binsheadfree(bp, &bufqueues[BQ_EMPTY], BQ_EMPTY);
        } else {
+
                /*
                 * It has valid data.  Put it on the end of the appropriate
                 * queue, so that it'll stick around for as long as possible.
@@ -1969,11 +2738,32 @@ buf_brelse(buf_t bp)
                        whichq = BQ_LRU;                /* valid data */
                bufq = &bufqueues[whichq];
 
-               CLR(bp->b_flags, (B_AGE | B_ASYNC | B_NOCACHE));
+               bp->b_timestamp = buf_timestamp();
 
-               lck_mtx_lock(buf_mtxp);
-
-               binstailfree(bp, bufq, whichq);
+               lck_mtx_lock_spin(buf_mtxp);
+               
+               /*
+                * the buf_brelse_shadow routine doesn't take 'ownership'
+                * of the parent buf_t... it updates state that is protected by
+                * the buf_mtxp, and checks for BL_BUSY to determine whether to
+                * put the buf_t back on a free list.  b_shadow_ref is protected
+                * by the lock, and since we have not yet cleared B_BUSY, we need
+                * to check it while holding the lock to insure that one of us
+                * puts this buf_t back on a free list when it is safe to do so
+                */
+               if (bp->b_shadow_ref == 0) {
+                       CLR(bp->b_flags, (B_AGE | B_ASYNC | B_NOCACHE));
+                       bp->b_whichq = whichq;
+                       binstailfree(bp, bufq, whichq);
+               } else {
+                       /*
+                        * there are still cloned buf_t's pointing
+                        * at this guy... need to keep it off the
+                        * freelists until a buf_brelse is done on 
+                        * the last clone
+                        */
+                       CLR(bp->b_flags, (B_ASYNC | B_NOCACHE));
+               }
        }
        if (needbuffer) {
                /*
@@ -1996,6 +2786,7 @@ buf_brelse(buf_t bp)
         * Unlock the buffer.
         */
        CLR(bp->b_lflags, (BL_BUSY | BL_WANTED));
+       buf_busycount--;
 
        lck_mtx_unlock(buf_mtxp);
 
@@ -2012,7 +2803,7 @@ buf_brelse(buf_t bp)
                wakeup(bp);
        }
        KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 388)) | DBG_FUNC_END,
-                    (int)bp, (int)bp->b_datap, bp->b_flags, 0, 0);
+                    bp, bp->b_datap, bp->b_flags, 0, 0);
 }
 
 /*
@@ -2026,10 +2817,13 @@ static boolean_t
 incore(vnode_t vp, daddr64_t blkno)
 {
         boolean_t retval;
+       struct  bufhashhdr *dp;
 
-       lck_mtx_lock(buf_mtxp);
+       dp = BUFHASH(vp, blkno);
+
+       lck_mtx_lock_spin(buf_mtxp);
 
-       if (incore_locked(vp, blkno))
+       if (incore_locked(vp, blkno, dp))
                retval = TRUE;
        else
                retval = FALSE;
@@ -2040,23 +2834,45 @@ incore(vnode_t vp, daddr64_t blkno)
 
 
 static buf_t
-incore_locked(vnode_t vp, daddr64_t blkno)
+incore_locked(vnode_t vp, daddr64_t blkno, struct bufhashhdr *dp)
 {
        struct buf *bp;
 
-       bp = BUFHASH(vp, blkno)->lh_first;
-
        /* Search hash chain */
-       for (; bp != NULL; bp = bp->b_hash.le_next) {
+       for (bp = dp->lh_first; bp != NULL; bp = bp->b_hash.le_next) {
                if (bp->b_lblkno == blkno && bp->b_vp == vp &&
                    !ISSET(bp->b_flags, B_INVAL)) {
                        return (bp);
                }
        }
-       return (0);
+       return (NULL);
 }
 
 
+void
+buf_wait_for_shadow_io(vnode_t vp, daddr64_t blkno)
+{
+       buf_t bp;
+       struct  bufhashhdr *dp;
+
+       dp = BUFHASH(vp, blkno);
+
+       lck_mtx_lock_spin(buf_mtxp);
+
+       for (;;) {
+               if ((bp = incore_locked(vp, blkno, dp)) == NULL)
+                       break;
+
+               if (bp->b_shadow_ref == 0)
+                       break;
+
+               SET(bp->b_lflags, BL_WANTED_REF);
+
+               (void) msleep(bp, buf_mtxp, PSPIN | (PRIBIO+1), "buf_wait_for_shadow", NULL);
+       }
+       lck_mtx_unlock(buf_mtxp);
+}
+       
 /* XXX FIXME -- Update the comment to reflect the UBC changes (please) -- */
 /*
  * Get a block of requested size that is associated with
@@ -2077,16 +2893,18 @@ buf_getblk(vnode_t vp, daddr64_t blkno, int size, int slpflag, int slptimeo, int
        int ret_only_valid;
        struct timespec ts;
        int upl_flags;
+       struct  bufhashhdr *dp;
 
        KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 386)) | DBG_FUNC_START,
-                    (int)(blkno * PAGE_SIZE), size, operation, 0, 0);
+                    (uintptr_t)(blkno * PAGE_SIZE), size, operation, 0, 0);
 
        ret_only_valid = operation & BLK_ONLYVALID;
        operation &= ~BLK_ONLYVALID;
+       dp = BUFHASH(vp, blkno);
 start:
-       lck_mtx_lock(buf_mtxp);
-start_locked:
-       if ((bp = incore_locked(vp, blkno))) {
+       lck_mtx_lock_spin(buf_mtxp);
+
+       if ((bp = incore_locked(vp, blkno, dp))) {
                /*
                 * Found in the Buffer Cache
                 */
@@ -2108,6 +2926,9 @@ start_locked:
                                ts.tv_sec = (slptimeo/1000);
                                ts.tv_nsec = (slptimeo % 1000) * 10  * NSEC_PER_USEC * 1000;
 
+                               KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 396)) | DBG_FUNC_NONE,
+                                            (uintptr_t)blkno, size, operation, 0, 0);
+
                                err = msleep(bp, buf_mtxp, slpflag | PDROP | (PRIBIO + 1), "buf_getblk", &ts);
 
                                /*
@@ -2132,20 +2953,22 @@ start_locked:
                        /*
                         * buffer in core and not busy
                         */
-                       if ( (bp->b_upl) )
-                               panic("buffer has UPL, but not marked BUSY: %x", bp);
                        SET(bp->b_lflags, BL_BUSY);
                        SET(bp->b_flags, B_CACHE);
-#ifdef JOE_DEBUG
-                       bp->b_owner = current_thread();
-                       bp->b_tag   = 1;
-#endif
+                       buf_busycount++;
+
                        bremfree_locked(bp);
                        bufstats.bufs_incore++;
                        
                        lck_mtx_unlock(buf_mtxp);
+#ifdef JOE_DEBUG
+                       bp->b_owner = current_thread();
+                       bp->b_tag   = 1;
+#endif
+                       if ( (bp->b_upl) )
+                               panic("buffer has UPL, but not marked BUSY: %p", bp);
 
-                       if ( !ret_only_valid)
+                       if ( !ret_only_valid && bp->b_bufsize != size)
                                allocbuf(bp, size);
 
                        upl_flags = 0;
@@ -2179,7 +3002,7 @@ start_locked:
                                        } else 
                                                CLR(bp->b_flags, (B_DONE | B_CACHE | B_WASDIRTY | B_DELWRI));
 
-                                       kret = ubc_upl_map(upl, (vm_address_t *)&(bp->b_datap));
+                                       kret = ubc_upl_map(upl, (vm_offset_t*)&(bp->b_datap));
 
                                        if (kret != KERN_SUCCESS)
                                                panic("getblk: ubc_upl_map() failed with (%d)", kret);
@@ -2206,12 +3029,11 @@ start_locked:
                        lck_mtx_unlock(buf_mtxp);
                        return (NULL);
                }
-
-               if ((UBCINVALID(vp)) || !(UBCINFOEXISTS(vp)))
+               if ((vnode_isreg(vp) == 0) || (UBCINFOEXISTS(vp) == 0) /*|| (vnode_issystem(vp) == 1)*/)
                        operation = BLK_META;
 
                if ((bp = getnewbuf(slpflag, slptimeo, &queue)) == NULL)
-                       goto start_locked;
+                       goto start;
 
                /*
                 * getnewbuf may block for a number of different reasons...
@@ -2220,7 +3042,7 @@ start_locked:
                 * the hash... if we see it incore at this point we dump
                 * the buffer we were working on and start over
                 */
-               if (incore_locked(vp, blkno)) {
+               if (incore_locked(vp, blkno, dp)) {
                        SET(bp->b_flags, B_INVAL);
                        binshash(bp, &invalhash);
 
@@ -2249,9 +3071,9 @@ start_locked:
                 */
                binshash(bp, BUFHASH(vp, blkno)); 
 
-               lck_mtx_unlock(buf_mtxp);
+               bgetvp_locked(vp, bp);
 
-               bgetvp(vp, bp);
+               lck_mtx_unlock(buf_mtxp);
 
                allocbuf(bp, size);
 
@@ -2267,7 +3089,7 @@ start_locked:
                         * in bufstats are protected with either
                         * buf_mtxp or iobuffer_mtxp
                         */
-                       OSAddAtomic(1, &bufstats.bufs_miss);
+                       OSAddAtomicLong(1, &bufstats.bufs_miss);
                        break;
 
                case BLK_WRITE:
@@ -2283,7 +3105,7 @@ start_locked:
                        int     bmap_flags;
 
                        if ( (bp->b_upl) )
-                               panic("bp already has UPL: %x",bp);
+                               panic("bp already has UPL: %p",bp);
 
                        f_offset = ubc_blktooff(vp, blkno);
 
@@ -2297,8 +3119,8 @@ start_locked:
 
                        if (kret != KERN_SUCCESS)
                                panic("Failed to create UPL");
-#ifdef  UPL_DEBUG
-                       upl_ubc_alias_set(upl, bp, 4);
+#if  UPL_DEBUG
+                       upl_ubc_alias_set(upl, (uintptr_t) bp, (uintptr_t) 4);
 #endif /* UPL_DEBUG */
                        bp->b_upl = upl;
 
@@ -2311,7 +3133,7 @@ start_locked:
 
                                SET(bp->b_flags, B_CACHE | B_DONE);
 
-                               OSAddAtomic(1, &bufstats.bufs_vmhits);
+                               OSAddAtomicLong(1, &bufstats.bufs_vmhits);
 
                                bp->b_validoff = 0;
                                bp->b_dirtyoff = 0;
@@ -2342,9 +3164,9 @@ start_locked:
                                if ((long)contig_bytes < bp->b_bcount)
                                        bp->b_blkno = bp->b_lblkno;
                        } else {
-                               OSAddAtomic(1, &bufstats.bufs_miss);
+                               OSAddAtomicLong(1, &bufstats.bufs_miss);
                        }
-                       kret = ubc_upl_map(upl, (vm_address_t *)&(bp->b_datap));
+                       kret = ubc_upl_map(upl, (vm_offset_t *)&(bp->b_datap));
 
                        if (kret != KERN_SUCCESS)
                                panic("getblk: ubc_upl_map() failed with (%d)", kret);
@@ -2357,15 +3179,10 @@ start_locked:
                }
        }
        KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 386)) | DBG_FUNC_END,
-                    (int)bp, (int)bp->b_datap, bp->b_flags, 3, 0);
+                    bp, bp->b_datap, bp->b_flags, 3, 0);
 
 #ifdef JOE_DEBUG
-       bp->b_stackgetblk[0] = __builtin_return_address(0);
-       bp->b_stackgetblk[1] = __builtin_return_address(1);
-       bp->b_stackgetblk[2] = __builtin_return_address(2);
-       bp->b_stackgetblk[3] = __builtin_return_address(3);
-       bp->b_stackgetblk[4] = __builtin_return_address(4);
-       bp->b_stackgetblk[5] = __builtin_return_address(5);
+       (void) OSBacktrace(&bp->b_stackgetblk[0], 6);
 #endif
        return (bp);
 }
@@ -2374,16 +3191,17 @@ start_locked:
  * Get an empty, disassociated buffer of given size.
  */
 buf_t
-buf_geteblk(size)
-       int size;
+buf_geteblk(int size)
 {
-       buf_t   bp;
+       buf_t   bp = NULL;
        int queue = BQ_EMPTY;
 
-       lck_mtx_lock(buf_mtxp);
+       do {
+               lck_mtx_lock_spin(buf_mtxp);
+
+               bp = getnewbuf(0, 0, &queue);
+       } while (bp == NULL);
 
-       while ((bp = getnewbuf(0, 0, &queue)) == 0)
-               ;
        SET(bp->b_flags, (B_META|B_INVAL));
 
 #if DIAGNOSTIC
@@ -2401,60 +3219,96 @@ buf_geteblk(size)
        return (bp);
 }
 
-/*
- * Zones for the meta data buffers
- */
+uint32_t
+buf_redundancy_flags(buf_t bp)
+{
+       return bp->b_redundancy_flags;
+}
 
-#define MINMETA 512
-#define MAXMETA 4096
+void
+buf_set_redundancy_flags(buf_t bp, uint32_t flags)
+{
+       SET(bp->b_redundancy_flags, flags);
+}
 
-struct meta_zone_entry {
-       zone_t mz_zone;
-       vm_size_t mz_size;
-       vm_size_t mz_max;
-       char *mz_name;
-};
+void
+buf_clear_redundancy_flags(buf_t bp, uint32_t flags)
+{
+       CLR(bp->b_redundancy_flags, flags);
+}
 
-struct meta_zone_entry meta_zones[] = {
-       {NULL, (MINMETA * 1), 128 * (MINMETA * 1), "buf.512" },
-       {NULL, (MINMETA * 2),  64 * (MINMETA * 2), "buf.1024" },
-       {NULL, (MINMETA * 4),  16 * (MINMETA * 4), "buf.2048" },
-       {NULL, (MINMETA * 8), 512 * (MINMETA * 8), "buf.4096" },
-       {NULL, 0, 0, "" } /* End */
-};
 
-/*
- * Initialize the meta data zones
- */
-static void
-bufzoneinit(void)
+
+static void *
+recycle_buf_from_pool(int nsize)
 {
-       int i;
+       buf_t   bp;
+       void    *ptr = NULL;
 
-       for (i = 0; meta_zones[i].mz_size != 0; i++) {
-               meta_zones[i].mz_zone = 
-                               zinit(meta_zones[i].mz_size,
-                                       meta_zones[i].mz_max,
-                                       PAGE_SIZE,
-                                       meta_zones[i].mz_name);
+       lck_mtx_lock_spin(buf_mtxp);
+
+       TAILQ_FOREACH(bp, &bufqueues[BQ_META], b_freelist) {
+               if (ISSET(bp->b_flags, B_DELWRI) || bp->b_bufsize != nsize)
+                       continue;
+               ptr = (void *)bp->b_datap;
+               bp->b_bufsize = 0;
+
+               bcleanbuf(bp, TRUE);
+               break;
        }
-       buf_hdr_zone = zinit(sizeof(struct buf), 32, PAGE_SIZE, "buf headers");
+       lck_mtx_unlock(buf_mtxp);
+
+       return (ptr);
 }
 
-static __inline__ zone_t
-getbufzone(size_t size)
+
+
+int zalloc_nopagewait_failed = 0;
+int recycle_buf_failed = 0;
+
+static void *
+grab_memory_for_meta_buf(int nsize)
 {
-       int i;
+       zone_t z;
+       void *ptr;
+       boolean_t was_vmpriv;
 
-       if ((size % 512) || (size < MINMETA) || (size > MAXMETA))
-               panic("getbufzone: incorect size = %d", size);
+       z = getbufzone(nsize);
 
-       for (i = 0; meta_zones[i].mz_size != 0; i++) {
-               if (meta_zones[i].mz_size >= size)
-                       break;
-       }
+       /*
+        * make sure we're NOT priviliged so that
+        * if a vm_page_grab is needed, it won't
+        * block if we're out of free pages... if
+        * it blocks, then we can't honor the
+        * nopagewait request
+        */
+       was_vmpriv = set_vm_privilege(FALSE);
 
-       return (meta_zones[i].mz_zone);
+       ptr = zalloc_nopagewait(z);
+
+       if (was_vmpriv == TRUE)
+               set_vm_privilege(TRUE);
+
+       if (ptr == NULL) {
+
+               zalloc_nopagewait_failed++;
+
+               ptr = recycle_buf_from_pool(nsize);
+
+               if (ptr == NULL) {
+
+                       recycle_buf_failed++;
+
+                       if (was_vmpriv == FALSE)
+                               set_vm_privilege(TRUE);
+
+                       ptr = zalloc(z);
+
+                       if (was_vmpriv == FALSE)
+                               set_vm_privilege(FALSE);
+               }
+       }
+       return (ptr);
 }
 
 /*
@@ -2482,7 +3336,6 @@ allocbuf(buf_t bp, int size)
                panic("allocbuf: buffer larger than MAXBSIZE requested");
 
        if (ISSET(bp->b_flags, B_META)) {
-               zone_t zprev, z;
                int    nsize = roundup(size, MINMETA);
 
                if (bp->b_datap) {
@@ -2490,16 +3343,19 @@ allocbuf(buf_t bp, int size)
 
                        if (ISSET(bp->b_flags, B_ZALLOC)) {
                                if (bp->b_bufsize < nsize) {
+                                       zone_t zprev;
+
                                        /* reallocate to a bigger size */
 
                                        zprev = getbufzone(bp->b_bufsize);
                                        if (nsize <= MAXMETA) {
                                                desired_size = nsize;
-                                               z = getbufzone(nsize);
-                                               bp->b_datap = (uintptr_t)zalloc(z);
+
+                                               /* b_datap not really a ptr */
+                                               *(void **)(&bp->b_datap) = grab_memory_for_meta_buf(nsize);
                                        } else {
                                                bp->b_datap = (uintptr_t)NULL;
-                                               kmem_alloc(kernel_map, (vm_offset_t *)&bp->b_datap, desired_size);
+                                               kmem_alloc_kobject(kernel_map, (vm_offset_t *)&bp->b_datap, desired_size);
                                                CLR(bp->b_flags, B_ZALLOC);
                                        }
                                        bcopy((void *)elem, (caddr_t)bp->b_datap, bp->b_bufsize);
@@ -2512,7 +3368,7 @@ allocbuf(buf_t bp, int size)
                                if ((vm_size_t)bp->b_bufsize < desired_size) {
                                        /* reallocate to a bigger size */
                                        bp->b_datap = (uintptr_t)NULL;
-                                       kmem_alloc(kernel_map, (vm_offset_t *)&bp->b_datap, desired_size);
+                                       kmem_alloc_kobject(kernel_map, (vm_offset_t *)&bp->b_datap, desired_size);
                                        bcopy((const void *)elem, (caddr_t)bp->b_datap, bp->b_bufsize);
                                        kmem_free(kernel_map, elem, bp->b_bufsize); 
                                } else {
@@ -2523,12 +3379,16 @@ allocbuf(buf_t bp, int size)
                        /* new allocation */
                        if (nsize <= MAXMETA) {
                                desired_size = nsize;
-                               z = getbufzone(nsize);
-                               bp->b_datap = (uintptr_t)zalloc(z);
+
+                               /* b_datap not really a ptr */
+                               *(void **)(&bp->b_datap) = grab_memory_for_meta_buf(nsize);
                                SET(bp->b_flags, B_ZALLOC);
                        } else
-                               kmem_alloc(kernel_map, (vm_offset_t *)&bp->b_datap, desired_size);
+                               kmem_alloc_kobject(kernel_map, (vm_offset_t *)&bp->b_datap, desired_size);
                }
+
+               if (bp->b_datap == 0)
+                       panic("allocbuf: NULL b_datap");
        }
        bp->b_bufsize = desired_size;
        bp->b_bcount = size;
@@ -2554,7 +3414,8 @@ allocbuf(buf_t bp, int size)
  *     on which it was found.
  *
  *     buf_mtxp is held upon entry
- *     returns with buf_mtxp locked
+ *     returns with buf_mtxp locked if new buf available
+ *     returns with buf_mtxp UNlocked if new buf NOT available
  */
 
 static buf_t
@@ -2572,19 +3433,30 @@ start:
        /*
         * invalid request gets empty queue
         */
-       if ((*queue > BQUEUES) || (*queue < 0)
+       if ((*queue >= BQUEUES) || (*queue < 0)
                || (*queue == BQ_LAUNDRY) || (*queue == BQ_LOCKED))
                *queue = BQ_EMPTY;
 
+
+       if (*queue == BQ_EMPTY && (bp = bufqueues[*queue].tqh_first))
+               goto found;
+
        /*
-        * (*queue == BQUEUES) means no preference
+        * need to grow number of bufs, add another one rather than recycling
         */
-       if (*queue != BQUEUES) {
-               /* Try for the requested queue first */
-               bp = bufqueues[*queue].tqh_first;
-               if (bp)
-                       goto found;
+       if (nbuf_headers < max_nbuf_headers) {
+               /*
+                * Increment  count now as lock 
+                * is dropped for allocation.
+                * That avoids over commits
+                */
+               nbuf_headers++;
+               goto add_newbufs;
        }
+       /* Try for the requested queue first */
+       bp = bufqueues[*queue].tqh_first;
+       if (bp)
+               goto found;
 
        /* Unable to use requested queue */
        age_bp = bufqueues[BQ_AGE].tqh_first;
@@ -2601,23 +3473,37 @@ start:
                        *queue = BQ_EMPTY;
                        goto found;
                }
+               /*
+                * We have seen is this is hard to trigger.
+                * This is an overcommit of nbufs but needed 
+                * in some scenarios with diskiamges
+                */
+
+add_newbufs:
                lck_mtx_unlock(buf_mtxp);
 
                /* Create a new temporary buffer header */
                bp = (struct buf *)zalloc(buf_hdr_zone);
-       
-               lck_mtx_lock(buf_mtxp);
-
+               
                if (bp) {
                        bufhdrinit(bp);
+                       bp->b_whichq = BQ_EMPTY;
+                       bp->b_timestamp = buf_timestamp();
                        BLISTNONE(bp);
-                       binshash(bp, &invalhash);
                        SET(bp->b_flags, B_HDRALLOC);
                        *queue = BQ_EMPTY;
+               }
+               lck_mtx_lock_spin(buf_mtxp);
+
+               if (bp) {
+                       binshash(bp, &invalhash);
                        binsheadfree(bp, &bufqueues[BQ_EMPTY], BQ_EMPTY);
                        buf_hdr_count++;
                        goto found;
                }
+               /* subtract already accounted bufcount */
+               nbuf_headers--;
+
                bufstats.bufs_sleeps++;
 
                /* wait for a free buffer of any kind */
@@ -2626,9 +3512,9 @@ start:
                ts.tv_sec = (slptimeo/1000);
                /* the hz value is 100; which leads to 10ms */
                ts.tv_nsec = (slptimeo % 1000) * NSEC_PER_USEC * 1000 * 10;
-               msleep(&needbuffer, buf_mtxp, slpflag|(PRIBIO+1), (char *)"getnewbuf", &ts);
 
-               return (0);
+               msleep(&needbuffer, buf_mtxp, slpflag | PDROP | (PRIBIO+1), "getnewbuf", &ts);
+               return (NULL);
        }
 
        /* Buffer available either on AGE or LRU or META */
@@ -2689,10 +3575,10 @@ start:
        }
 found:
        if (ISSET(bp->b_flags, B_LOCKED) || ISSET(bp->b_lflags, BL_BUSY))
-               panic("getnewbuf: bp @ 0x%x is LOCKED or BUSY! (flags 0x%x)\n", bp, bp->b_flags);
+               panic("getnewbuf: bp @ %p is LOCKED or BUSY! (flags 0x%x)\n", bp, bp->b_flags);
 
        /* Clean it */
-       if (bcleanbuf(bp)) {
+       if (bcleanbuf(bp, FALSE)) {
                /*
                 * moved to the laundry thread, buffer not ready
                 */
@@ -2705,24 +3591,19 @@ found:
 
 /* 
  * Clean a buffer.
- * Returns 0 is buffer is ready to use,
+ * Returns 0 if buffer is ready to use,
  * Returns 1 if issued a buf_bawrite() to indicate 
  * that the buffer is not ready.
  * 
  * buf_mtxp is held upon entry
  * returns with buf_mtxp locked
  */
-static int
-bcleanbuf(buf_t bp)
+int
+bcleanbuf(buf_t bp, boolean_t discard)
 {
-       ucred_t cred;
-
-
        /* Remove from the queue */
        bremfree_locked(bp);
 
-       /* Buffer is no longer on free lists. */
-       SET(bp->b_lflags, BL_BUSY);
 #ifdef JOE_DEBUG
        bp->b_owner = current_thread();
        bp->b_tag   = 2;
@@ -2732,84 +3613,93 @@ bcleanbuf(buf_t bp)
         * it on the LAUNDRY queue, and return 1
         */
        if (ISSET(bp->b_flags, B_DELWRI)) {
-               binstailfree(bp, &bufqueues[BQ_LAUNDRY], BQ_LAUNDRY);
-               blaundrycnt++;
+               if (discard) {
+                       SET(bp->b_lflags, BL_WANTDEALLOC);
+               }
+
+               bmovelaundry(bp);
 
                lck_mtx_unlock(buf_mtxp);
 
-               wakeup(&blaundrycnt);
-               /* and give it a chance to run */
+               wakeup(&bufqueues[BQ_LAUNDRY]);
+               /*
+                * and give it a chance to run
+                */
                (void)thread_block(THREAD_CONTINUE_NULL);
 
-               lck_mtx_lock(buf_mtxp);
+               lck_mtx_lock_spin(buf_mtxp);
+
                return (1);
        }
+#ifdef JOE_DEBUG
+       bp->b_owner = current_thread();
+       bp->b_tag   = 8;
+#endif
+       /*
+        * Buffer is no longer on any free list... we own it
+        */
+       SET(bp->b_lflags, BL_BUSY);
+       buf_busycount++;
+       
        bremhash(bp);
 
-       lck_mtx_unlock(buf_mtxp);
-
-       BLISTNONE(bp);
        /*
         * disassociate us from our vnode, if we had one...
         */
        if (bp->b_vp)
-               brelvp(bp);
+               brelvp_locked(bp);
 
-       if (ISSET(bp->b_flags, B_META)) {
-               vm_offset_t elem;
-
-               elem = (vm_offset_t)bp->b_datap;
-               bp->b_datap = (uintptr_t)0xdeadbeef;
+       lck_mtx_unlock(buf_mtxp);
 
-               if (ISSET(bp->b_flags, B_ZALLOC)) {
-                       zone_t z;
+       BLISTNONE(bp);
 
-                       z = getbufzone(bp->b_bufsize);
-                       zfree(z, (void *)elem);
-               } else
-                       kmem_free(kernel_map, elem, bp->b_bufsize); 
-       }
+       if (ISSET(bp->b_flags, B_META))
+               buf_free_meta_store(bp);
 
        trace(TR_BRELSE, pack(bp->b_vp, bp->b_bufsize), bp->b_lblkno);
 
-       /* clear out various other fields */
-       bp->b_bufsize = 0;
-       bp->b_datap = (uintptr_t)NULL;
-       bp->b_upl = (void *)NULL;
-       /*
-        * preserve the state of whether this buffer
-        * was allocated on the fly or not...
-        * the only other flag that should be set at
-        * this point is BL_BUSY...
-        */
+       buf_release_credentials(bp);
+       
+       bp->b_redundancy_flags = 0;
+
+       /* If discarding, just move to the empty queue */
+       if (discard) {
+               lck_mtx_lock_spin(buf_mtxp);
+               CLR(bp->b_flags, (B_META | B_ZALLOC | B_DELWRI | B_LOCKED | B_AGE | B_ASYNC | B_NOCACHE | B_FUA));
+               bp->b_whichq = BQ_EMPTY;
+               binshash(bp, &invalhash);
+               binsheadfree(bp, &bufqueues[BQ_EMPTY], BQ_EMPTY);
+               CLR(bp->b_lflags, BL_BUSY);
+               buf_busycount--;
+       } else {
+               /* Not discarding: clean up and prepare for reuse */
+               bp->b_bufsize = 0;
+               bp->b_datap = (uintptr_t)NULL;
+               bp->b_upl = (void *)NULL;
+               /*
+                * preserve the state of whether this buffer
+                * was allocated on the fly or not...
+                * the only other flag that should be set at
+                * this point is BL_BUSY...
+                */
 #ifdef JOE_DEBUG
-       bp->b_owner = current_thread();
-       bp->b_tag   = 3;
+               bp->b_owner = current_thread();
+               bp->b_tag   = 3;
 #endif
-       bp->b_lflags = BL_BUSY;
-       bp->b_flags = (bp->b_flags & B_HDRALLOC);
-       bp->b_dev = NODEV;
-       bp->b_blkno = bp->b_lblkno = 0;
-       bp->b_iodone = NULL;
-       bp->b_error = 0;
-       bp->b_resid = 0;
-       bp->b_bcount = 0;
-       bp->b_dirtyoff = bp->b_dirtyend = 0;
-       bp->b_validoff = bp->b_validend = 0;
-
-       /* nuke any credentials we were holding */
-       cred = bp->b_rcred;
-       if (cred != NOCRED) {
-               bp->b_rcred = NOCRED; 
-               kauth_cred_rele(cred);
-       }
-       cred = bp->b_wcred;
-       if (cred != NOCRED) {
-               bp->b_wcred = NOCRED;
-               kauth_cred_rele(cred);
+               bp->b_lflags = BL_BUSY;
+               bp->b_flags = (bp->b_flags & B_HDRALLOC);
+               bp->b_dev = NODEV;
+               bp->b_blkno = bp->b_lblkno = 0;
+               bp->b_iodone = NULL;
+               bp->b_error = 0;
+               bp->b_resid = 0;
+               bp->b_bcount = 0;
+               bp->b_dirtyoff = bp->b_dirtyend = 0;
+               bp->b_validoff = bp->b_validend = 0;
+               bzero(&bp->b_attr, sizeof(struct bufattr));
+
+               lck_mtx_lock_spin(buf_mtxp);
        }
-       lck_mtx_lock(buf_mtxp);
-
        return (0);
 }
 
@@ -2820,10 +3710,14 @@ buf_invalblkno(vnode_t vp, daddr64_t lblkno, int flags)
 {
         buf_t  bp;
        errno_t error;
+       struct bufhashhdr *dp;
+
+       dp = BUFHASH(vp, lblkno);
 
-       lck_mtx_lock(buf_mtxp);
 relook:        
-       if ((bp = incore_locked(vp, lblkno)) == (struct buf *)0) {
+       lck_mtx_lock_spin(buf_mtxp);
+
+       if ((bp = incore_locked(vp, lblkno, dp)) == (struct buf *)0) {
                lck_mtx_unlock(buf_mtxp);
                return (0);
        }
@@ -2834,15 +3728,17 @@ relook:
                }
                SET(bp->b_lflags, BL_WANTED);
 
-               error = msleep((caddr_t)bp, buf_mtxp, (PRIBIO + 1), (char *)"buf_invalblkno", 0);
+               error = msleep((caddr_t)bp, buf_mtxp, PDROP | (PRIBIO + 1), "buf_invalblkno", NULL);
 
-               if (error)
+               if (error) {
                        return (error);
+               }
                goto relook;
        }
        bremfree_locked(bp);
        SET(bp->b_lflags, BL_BUSY);
        SET(bp->b_flags, B_INVAL);
+       buf_busycount++;
 #ifdef JOE_DEBUG
        bp->b_owner = current_thread();
        bp->b_tag   = 4;
@@ -2859,7 +3755,7 @@ buf_drop(buf_t bp)
 {
         int need_wakeup = 0;
 
-       lck_mtx_lock(buf_mtxp);
+       lck_mtx_lock_spin(buf_mtxp);
 
        if (ISSET(bp->b_lflags, BL_WANTED)) {
                /*      
@@ -2868,10 +3764,15 @@ buf_drop(buf_t bp)
                 */
                need_wakeup = 1;
        }
+#ifdef JOE_DEBUG
+       bp->b_owner = current_thread();
+       bp->b_tag   = 9;
+#endif
        /*
         * Unlock the buffer.
         */
        CLR(bp->b_lflags, (BL_BUSY | BL_WANTED));
+       buf_busycount--;
 
        lck_mtx_unlock(buf_mtxp);
 
@@ -2888,7 +3789,7 @@ errno_t
 buf_acquire(buf_t bp, int flags, int slpflag, int slptimeo) {
         errno_t error;
 
-        lck_mtx_lock(buf_mtxp);
+        lck_mtx_lock_spin(buf_mtxp);
 
        error = buf_acquire_locked(bp, flags, slpflag, slptimeo);
 
@@ -2913,7 +3814,7 @@ buf_acquire_locked(buf_t bp, int flags, int slpflag, int slptimeo)
        }
         if (ISSET(bp->b_lflags, BL_BUSY)) {
                /*      
-                * since the mutex_lock may block, the buffer
+                * since the lck_mtx_lock may block, the buffer
                 * may become BUSY, so we need to
                 * recheck for a NOWAIT request
                 */
@@ -2924,7 +3825,7 @@ buf_acquire_locked(buf_t bp, int flags, int slpflag, int slptimeo)
                /* the hz value is 100; which leads to 10ms */
                ts.tv_sec = (slptimeo/100);
                ts.tv_nsec = (slptimeo % 100) * 10  * NSEC_PER_USEC * 1000;
-               error = msleep((caddr_t)bp, buf_mtxp, slpflag | (PRIBIO + 1), (char *)"buf_acquire", &ts);
+               error = msleep((caddr_t)bp, buf_mtxp, slpflag | (PRIBIO + 1), "buf_acquire", &ts);
 
                if (error)
                        return (error);
@@ -2933,6 +3834,8 @@ buf_acquire_locked(buf_t bp, int flags, int slpflag, int slptimeo)
        if (flags & BAC_REMOVE)
                bremfree_locked(bp);
        SET(bp->b_lflags, BL_BUSY);
+       buf_busycount++;
+
 #ifdef JOE_DEBUG
        bp->b_owner = current_thread();
        bp->b_tag   = 5;
@@ -2948,13 +3851,17 @@ buf_acquire_locked(buf_t bp, int flags, int slpflag, int slptimeo)
 errno_t
 buf_biowait(buf_t bp)
 {
-       lck_mtx_lock(buf_mtxp);
+       while (!ISSET(bp->b_flags, B_DONE)) {
 
-       while (!ISSET(bp->b_flags, B_DONE))
-               (void) msleep(bp, buf_mtxp, (PRIBIO+1), (char *)"buf_biowait", 0);
+               lck_mtx_lock_spin(buf_mtxp);
 
-       lck_mtx_unlock(buf_mtxp);
-       
+               if (!ISSET(bp->b_flags, B_DONE)) {
+                       DTRACE_IO1(wait__start, buf_t, bp);
+                       (void) msleep(bp, buf_mtxp, PDROP | (PRIBIO+1), "buf_biowait", NULL);
+                       DTRACE_IO1(wait__done, buf_t, bp);
+               } else
+                       lck_mtx_unlock(buf_mtxp);
+       }
        /* check for interruption of I/O (e.g. via NFS), then errors. */
        if (ISSET(bp->b_flags, B_EINTR)) {
                CLR(bp->b_flags, B_EINTR);
@@ -2965,6 +3872,7 @@ buf_biowait(buf_t bp)
                return (0);
 }
 
+
 /*
  * Mark I/O complete on a buffer.
  *
@@ -2981,20 +3889,37 @@ buf_biowait(buf_t bp)
  * (for swap pager, that puts swap buffers on the free lists (!!!),
  * for the vn device, that puts malloc'd buffers on the free lists!)
  */
-extern struct timeval priority_IO_timestamp_for_root;
-extern int hard_throttle_on_root;
 
 void
 buf_biodone(buf_t bp)
 {
+       mount_t mp;
+       struct bufattr *bap;
+       
        KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 387)) | DBG_FUNC_START,
-                    (int)bp, (int)bp->b_datap, bp->b_flags, 0, 0);
+                    bp, bp->b_datap, bp->b_flags, 0, 0);
 
        if (ISSET(bp->b_flags, B_DONE))
                panic("biodone already");
 
-        if (kdebug_enable) {
-               int    code = DKIO_DONE;
+       bap = &bp->b_attr;
+
+       if (bp->b_vp && bp->b_vp->v_mount) {
+               mp = bp->b_vp->v_mount;
+       } else {
+               mp = NULL;
+       }
+       
+       if (mp && (bp->b_flags & B_READ) == 0) {
+               update_last_io_time(mp);
+               INCR_PENDING_IO(-(pending_io_t)buf_count(bp), mp->mnt_pending_write_size);
+       } else if (mp) {
+               INCR_PENDING_IO(-(pending_io_t)buf_count(bp), mp->mnt_pending_read_size);
+       }
+
+       if (kdebug_enable) {
+               int code    = DKIO_DONE;
+               int io_tier = GET_BUFATTR_IO_TIER(bap);
 
                if (bp->b_flags & B_READ)
                        code |= DKIO_READ;
@@ -3006,21 +3931,33 @@ buf_biodone(buf_t bp)
                else if (bp->b_flags & B_PAGEIO)
                        code |= DKIO_PAGING;
 
-               KERNEL_DEBUG_CONSTANT(FSDBG_CODE(DBG_DKRW, code) | DBG_FUNC_NONE,
-                                     (unsigned int)bp, (unsigned int)bp->b_vp,
-                                     bp->b_resid, bp->b_error, 0);
+               if (io_tier != 0)
+                       code |= DKIO_THROTTLE;
+
+               code |= ((io_tier << DKIO_TIER_SHIFT) & DKIO_TIER_MASK);
+
+               if (bp->b_flags & B_PASSIVE)
+                       code |= DKIO_PASSIVE;
+
+               if (bap->ba_flags & BA_NOCACHE)
+                       code |= DKIO_NOCACHE;
+
+               KERNEL_DEBUG_CONSTANT_IST(KDEBUG_COMMON, FSDBG_CODE(DBG_DKRW, code) | DBG_FUNC_NONE,
+                                         buf_kernel_addrperm_addr(bp), (uintptr_t)VM_KERNEL_ADDRPERM(bp->b_vp), bp->b_resid, bp->b_error, 0);
         }
-       if ((bp->b_vp != NULLVP) &&
-           ((bp->b_flags & (B_PAGEIO | B_READ)) == (B_PAGEIO | B_READ)) &&
-           (bp->b_vp->v_mount->mnt_kern_flag & MNTK_ROOTDEV)) {
-               microuptime(&priority_IO_timestamp_for_root);
-               hard_throttle_on_root = 0;
-       }
+
        /*
         * I/O was done, so don't believe
-        * the DIRTY state from VM anymore
+        * the DIRTY state from VM anymore...
+        * and we need to reset the THROTTLED/PASSIVE
+        * indicators
         */
-       CLR(bp->b_flags, B_WASDIRTY);
+       CLR(bp->b_flags, (B_WASDIRTY | B_PASSIVE));
+       CLR(bap->ba_flags, (BA_META | BA_NOCACHE | BA_DELAYIDLESLEEP));
+
+       SET_BUFATTR_IO_TIER(bap, 0);
+
+       DTRACE_IO1(done, buf_t, bp);
 
        if (!ISSET(bp->b_flags, B_READ) && !ISSET(bp->b_flags, B_RAW))
                /*
@@ -3032,26 +3969,28 @@ buf_biodone(buf_t bp)
 
        if (ISSET(bp->b_flags, (B_CALL | B_FILTER))) {  /* if necessary, call out */
                void    (*iodone_func)(struct buf *, void *) = bp->b_iodone;
-               void    *arg = (void *)bp->b_transaction;
+               void    *arg = bp->b_transaction;
                int     callout = ISSET(bp->b_flags, B_CALL);
 
+               if (iodone_func == NULL)
+                       panic("biodone: bp @ %p has NULL b_iodone!\n", bp);                     
+
                CLR(bp->b_flags, (B_CALL | B_FILTER));  /* filters and callouts are one-shot */
                bp->b_iodone = NULL;
                bp->b_transaction = NULL;
 
-               if (iodone_func == NULL) {
-                       panic("biodone: bp @ 0x%x has NULL b_iodone!\n", bp);                   
-               } else { 
-                       if (callout)
-                               SET(bp->b_flags, B_DONE);       /* note that it's done */
-                       (*iodone_func)(bp, arg);
-               }
                if (callout)
-                       /*
-                        * assumes that the call back function takes
+                       SET(bp->b_flags, B_DONE);       /* note that it's done */
+
+               (*iodone_func)(bp, arg);
+
+               if (callout) {
+                       /*
+                        * assumes that the callback function takes
                         * ownership of the bp and deals with releasing it if necessary
                         */
-                       goto biodone_done;
+                       goto biodone_done;
+               }
                /*
                 * in this case the call back function is acting
                 * strictly as a filter... it does not take
@@ -3079,7 +4018,7 @@ buf_biodone(buf_t bp)
                 * they do get to run, their going to re-set
                 * BL_WANTED and go back to sleep
                 */
-               lck_mtx_lock(buf_mtxp);
+               lck_mtx_lock_spin(buf_mtxp);
 
                CLR(bp->b_lflags, BL_WANTED);
                SET(bp->b_flags, B_DONE);               /* note that it's done */
@@ -3090,7 +4029,19 @@ buf_biodone(buf_t bp)
        }
 biodone_done:
        KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 387)) | DBG_FUNC_END,
-                    (int)bp, (int)bp->b_datap, bp->b_flags, 0, 0);
+                 (uintptr_t)bp, (uintptr_t)bp->b_datap, bp->b_flags, 0, 0);
+}
+
+/*
+ * Obfuscate buf pointers.
+ */
+vm_offset_t
+buf_kernel_addrperm_addr(void * addr)
+{
+       if ((vm_offset_t)addr == 0)
+               return 0;
+       else
+               return ((vm_offset_t)addr + buf_kernel_addrperm);
 }
 
 /*
@@ -3102,7 +4053,7 @@ count_lock_queue(void)
        buf_t   bp;
        int     n = 0;
 
-       lck_mtx_lock(buf_mtxp);
+       lck_mtx_lock_spin(buf_mtxp);
 
        for (bp = bufqueues[BQ_LOCKED].tqh_first; bp;
            bp = bp->b_freelist.tqe_next)
@@ -3114,17 +4065,12 @@ count_lock_queue(void)
 
 /*
  * Return a count of 'busy' buffers. Used at the time of shutdown.
+ * note: This is also called from the mach side in debug context in kdp.c
  */
 int
 count_busy_buffers(void)
 {
-       buf_t   bp;
-       int     nbusy = 0;
-
-       for (bp = &buf[nbuf]; --bp >= buf; )
-               if (!ISSET(bp->b_flags, B_INVAL) && ISSET(bp->b_lflags, BL_BUSY))
-                       nbusy++;
-       return (nbusy);
+       return buf_busycount + bufstats.bufs_iobufinuse;
 }
 
 #if DIAGNOSTIC
@@ -3137,8 +4083,8 @@ void
 vfs_bufstats()
 {
        int i, j, count;
-       register struct buf *bp;
-       register struct bqueues *dp;
+       struct buf *bp;
+       struct bqueues *dp;
        int counts[MAXBSIZE/CLBYTES+1];
        static char *bname[BQUEUES] =
                { "LOCKED", "LRU", "AGE", "EMPTY", "META", "LAUNDRY" };
@@ -3165,7 +4111,7 @@ vfs_bufstats()
 }
 #endif /* DIAGNOSTIC */
 
-#define        NRESERVEDIOBUFS 64
+#define        NRESERVEDIOBUFS 128
 
 
 buf_t
@@ -3173,14 +4119,14 @@ alloc_io_buf(vnode_t vp, int priv)
 {
        buf_t   bp;
 
-       lck_mtx_lock(iobuffer_mtxp);
+       lck_mtx_lock_spin(iobuffer_mtxp);
 
-       while (((niobuf - NRESERVEDIOBUFS < bufstats.bufs_iobufinuse) && !priv) || 
+       while (((niobuf_headers - NRESERVEDIOBUFS < bufstats.bufs_iobufinuse) && !priv) || 
               (bp = iobufqueue.tqh_first) == NULL) {
                bufstats.bufs_iobufsleeps++;
 
                need_iobuffer = 1;
-               (void) msleep(&need_iobuffer, iobuffer_mtxp, (PRIBIO+1), (const char *)"alloc_io_buf", 0);
+               (void) msleep(&need_iobuffer, iobuffer_mtxp, PSPIN | (PRIBIO+1), (const char *)"alloc_io_buf", NULL);
        }
        TAILQ_REMOVE(&iobufqueue, bp, b_freelist);
 
@@ -3202,6 +4148,7 @@ alloc_io_buf(vnode_t vp, int priv)
        bp->b_datap = 0;
        bp->b_flags = 0;
        bp->b_lflags = BL_BUSY | BL_IOBUF;
+       bp->b_redundancy_flags = 0;
        bp->b_blkno = bp->b_lblkno = 0;
 #ifdef JOE_DEBUG
        bp->b_owner = current_thread();
@@ -3214,6 +4161,7 @@ alloc_io_buf(vnode_t vp, int priv)
        bp->b_bufsize = 0;
        bp->b_upl = NULL;
        bp->b_vp = vp;
+       bzero(&bp->b_attr, sizeof(struct bufattr));
 
        if (vp && (vp->v_type == VBLK || vp->v_type == VCHR))
                bp->b_dev = vp->v_rdev;
@@ -3235,7 +4183,10 @@ free_io_buf(buf_t bp)
        bp->b_vp = NULL;
        bp->b_flags = B_INVAL;
 
-       lck_mtx_lock(iobuffer_mtxp);
+       /* Zero out the bufattr and its flags before relinquishing this iobuf */
+       bzero (&bp->b_attr, sizeof(struct bufattr));
+       
+       lck_mtx_lock_spin(iobuffer_mtxp);
 
        binsheadfree(bp, &iobufqueue, -1);
 
@@ -3252,6 +4203,9 @@ free_io_buf(buf_t bp)
                need_iobuffer = 0;
                need_wakeup = 1;
        }
+       if (bufstats.bufs_iobufinuse <= 0)
+               panic("free_io_buf: bp(%p) - bufstats.bufs_iobufinuse < 0", bp);
+
        bufstats.bufs_iobufinuse--;
 
        lck_mtx_unlock(iobuffer_mtxp);
@@ -3261,24 +4215,37 @@ free_io_buf(buf_t bp)
 }
 
 
+void
+buf_list_lock(void)
+{
+        lck_mtx_lock_spin(buf_mtxp);
+}
+
+void
+buf_list_unlock(void)
+{
+        lck_mtx_unlock(buf_mtxp);
+}
 
 /*
  * If getnewbuf() calls bcleanbuf() on the same thread
  * there is a potential for stack overrun and deadlocks.
  * So we always handoff the work to a worker thread for completion
  */
-#include <mach/mach_types.h>
-#include <mach/memory_object_types.h>
-#include <kern/sched_prim.h>
 
 
 static void
 bcleanbuf_thread_init(void)
 {
+       thread_t        thread = THREAD_NULL;
+
        /* create worker thread */
-       kernel_thread(kernel_task, bcleanbuf_thread);
+       kernel_thread_start((thread_continue_t)bcleanbuf_thread, NULL, &thread);
+       thread_deallocate(thread);
 }
 
+typedef int (*bcleanbufcontinuation)(int);
+
 static void
 bcleanbuf_thread(void)
 {
@@ -3287,17 +4254,27 @@ bcleanbuf_thread(void)
        int loopcnt = 0;
 
        for (;;) {
-               lck_mtx_lock(buf_mtxp);
-
-               while (blaundrycnt == 0)
-                       (void)msleep((void *)&blaundrycnt, buf_mtxp, PRIBIO, "blaundry", 0);
+               lck_mtx_lock_spin(buf_mtxp);
 
-               bp = TAILQ_FIRST(&bufqueues[BQ_LAUNDRY]);
+               while ( (bp = TAILQ_FIRST(&bufqueues[BQ_LAUNDRY])) == NULL) {
+                       (void)msleep0(&bufqueues[BQ_LAUNDRY], buf_mtxp, PRIBIO|PDROP, "blaundry", 0, (bcleanbufcontinuation)bcleanbuf_thread);
+               }
+               
                /*
                 * Remove from the queue
                 */
                bremfree_locked(bp);
-               blaundrycnt--;
+
+               /*
+                * Buffer is no longer on any free list
+                */
+               SET(bp->b_lflags, BL_BUSY);
+               buf_busycount++;
+
+#ifdef JOE_DEBUG
+               bp->b_owner = current_thread();
+               bp->b_tag   = 10;
+#endif
 
                lck_mtx_unlock(buf_mtxp);
                /*
@@ -3306,18 +4283,35 @@ bcleanbuf_thread(void)
                error = bawrite_internal(bp, 0);
 
                if (error) {
-                       lck_mtx_lock(buf_mtxp);
+                       bp->b_whichq = BQ_LAUNDRY;
+                       bp->b_timestamp = buf_timestamp();
+
+                       lck_mtx_lock_spin(buf_mtxp);
 
                        binstailfree(bp, &bufqueues[BQ_LAUNDRY], BQ_LAUNDRY);
                        blaundrycnt++;
 
-                       lck_mtx_unlock(buf_mtxp);
+                       /* we never leave a busy page on the laundry queue */
+                       CLR(bp->b_lflags, BL_BUSY);
+                       buf_busycount--;
+#ifdef JOE_DEBUG
+                       bp->b_owner = current_thread();
+                       bp->b_tag   = 11;
+#endif
 
-                       if (loopcnt > 10) {
-                               (void)tsleep((void *)&blaundrycnt, PRIBIO, "blaundry", 1);
+                       lck_mtx_unlock(buf_mtxp);
+                       
+                       if (loopcnt > MAXLAUNDRY) {
+                               /*
+                                * bawrite_internal() can return errors if we're throttled. If we've
+                                * done several I/Os and failed, give the system some time to unthrottle
+                                * the vnode
+                                */
+                               (void)tsleep((void *)&bufqueues[BQ_LAUNDRY], PRIBIO, "blaundry", 1);
                                loopcnt = 0;
                        } else {
-                               (void)thread_block(THREAD_CONTINUE_NULL);
+                               /* give other threads a chance to run */
+                               (void)thread_block(THREAD_CONTINUE_NULL);
                                loopcnt++;
                        }
                }
@@ -3367,7 +4361,7 @@ brecover_data(buf_t bp)
        }
        bp->b_upl = upl;
                                        
-       kret = ubc_upl_map(upl, (vm_address_t *)&(bp->b_datap));
+       kret = ubc_upl_map(upl, (vm_offset_t *)&(bp->b_datap));
 
        if (kret != KERN_SUCCESS)
                panic("getblk: ubc_upl_map() failed with (%d)", kret);
@@ -3381,6 +4375,137 @@ dump_buffer:
        return(0);
 }
 
+boolean_t 
+buffer_cache_gc(int all)
+{
+       buf_t bp;
+       boolean_t did_large_zfree = FALSE;
+       boolean_t need_wakeup = FALSE;
+       int now = buf_timestamp();
+       uint32_t found = 0;
+       struct bqueues privq;
+       int thresh_hold = BUF_STALE_THRESHHOLD;
+
+       if (all)
+               thresh_hold = 0;
+       /* 
+        * We only care about metadata (incore storage comes from zalloc()).
+        * Unless "all" is set (used to evict meta data buffers in preparation
+        * for deep sleep), we only evict up to BUF_MAX_GC_BATCH_SIZE buffers
+        * that have not been accessed in the last BUF_STALE_THRESHOLD seconds.
+        * BUF_MAX_GC_BATCH_SIZE controls both the hold time of the global lock
+        * "buf_mtxp" and the length of time we spend compute bound in the GC
+        * thread which calls this function
+        */
+       lck_mtx_lock(buf_mtxp);
+
+       do {
+               found = 0;
+               TAILQ_INIT(&privq);
+               need_wakeup = FALSE;
+
+               while (((bp = TAILQ_FIRST(&bufqueues[BQ_META]))) && 
+                               (now > bp->b_timestamp) &&
+                               (now - bp->b_timestamp > thresh_hold) && 
+                               (found < BUF_MAX_GC_BATCH_SIZE)) {
+
+                       /* Remove from free list */
+                       bremfree_locked(bp);
+                       found++;
+
+#ifdef JOE_DEBUG
+                       bp->b_owner = current_thread();
+                       bp->b_tag   = 12;
+#endif
+
+                       /* If dirty, move to laundry queue and remember to do wakeup */
+                       if (ISSET(bp->b_flags, B_DELWRI)) {
+                               SET(bp->b_lflags, BL_WANTDEALLOC);
+
+                               bmovelaundry(bp);
+                               need_wakeup = TRUE;
+
+                               continue;
+                       }
+
+                       /* 
+                        * Mark busy and put on private list.  We could technically get 
+                        * away without setting BL_BUSY here.
+                        */
+                       SET(bp->b_lflags, BL_BUSY);
+                       buf_busycount++;
+
+                       /* 
+                        * Remove from hash and dissociate from vp.
+                        */
+                       bremhash(bp);
+                       if (bp->b_vp) {
+                               brelvp_locked(bp);
+                       }
+
+                       TAILQ_INSERT_TAIL(&privq, bp, b_freelist);
+               }
+
+               if (found == 0) {
+                       break;
+               }
+
+               /* Drop lock for batch processing */
+               lck_mtx_unlock(buf_mtxp);
+
+               /* Wakeup and yield for laundry if need be */
+               if (need_wakeup) {
+                       wakeup(&bufqueues[BQ_LAUNDRY]);
+                       (void)thread_block(THREAD_CONTINUE_NULL);
+               }
+
+               /* Clean up every buffer on private list */
+               TAILQ_FOREACH(bp, &privq, b_freelist) {
+                       /* Take note if we've definitely freed at least a page to a zone */
+                       if ((ISSET(bp->b_flags, B_ZALLOC)) && (buf_size(bp) >= PAGE_SIZE)) {
+                               did_large_zfree = TRUE;
+                       }    
+
+                       trace(TR_BRELSE, pack(bp->b_vp, bp->b_bufsize), bp->b_lblkno);
+
+                       /* Free Storage */
+                       buf_free_meta_store(bp);
+
+                       /* Release credentials */
+                       buf_release_credentials(bp);
+
+                       /* Prepare for moving to empty queue */
+                       CLR(bp->b_flags, (B_META | B_ZALLOC | B_DELWRI | B_LOCKED 
+                                               | B_AGE | B_ASYNC | B_NOCACHE | B_FUA));
+                       bp->b_whichq = BQ_EMPTY;
+                       BLISTNONE(bp);
+               }
+               lck_mtx_lock(buf_mtxp);
+
+               /* Back under lock, move them all to invalid hash and clear busy */
+               TAILQ_FOREACH(bp, &privq, b_freelist) {
+                       binshash(bp, &invalhash);
+                       CLR(bp->b_lflags, BL_BUSY);
+                       buf_busycount--;
+
+#ifdef JOE_DEBUG
+                       if (bp->b_owner != current_thread()) {
+                               panic("Buffer stolen from buffer_cache_gc()");
+                       }
+                       bp->b_owner = current_thread();
+                       bp->b_tag   = 13;
+#endif
+               }
+
+               /* And do a big bulk move to the empty queue */
+               TAILQ_CONCAT(&bufqueues[BQ_EMPTY], &privq, b_freelist);
+
+       } while (all && (found == BUF_MAX_GC_BATCH_SIZE));
+
+       lck_mtx_unlock(buf_mtxp);
+
+       return did_large_zfree;
+}
 
 
 /*
@@ -3439,6 +4564,8 @@ bflushq(int whichq, mount_t mp)
                bp->b_tag   = 7;
 #endif
                SET(bp->b_lflags, BL_BUSY);
+               buf_busycount++;
+
                flush_table[buf_count] = bp;
                buf_count++;
                total_writes++;
@@ -3468,334 +4595,3 @@ bflushq(int whichq, mount_t mp)
        return (total_writes);
 }
 #endif
-
-
-#if BALANCE_QUEUES
-
-/* XXX move this to a separate file */
-
-/*
- * NOTE: THIS CODE HAS NOT BEEN UPDATED
- * WITH RESPECT TO THE NEW LOCKING MODEL
- */
-   
-
-/*
- * Dynamic Scaling of the Buffer Queues
- */
-
-typedef long long blsize_t;
-
-blsize_t MAXNBUF; /* initialize to (sane_size / PAGE_SIZE) */
-/* Global tunable limits */
-blsize_t nbufh;                        /* number of buffer headers */
-blsize_t nbuflow;              /* minimum number of buffer headers required */
-blsize_t nbufhigh;             /* maximum number of buffer headers allowed */
-blsize_t nbuftarget;   /* preferred number of buffer headers */
-
-/*
- * assertions:
- *
- * 1.  0 < nbuflow <= nbufh <= nbufhigh
- * 2.  nbufhigh <= MAXNBUF
- * 3.  0 < nbuflow <= nbuftarget <= nbufhigh
- * 4.  nbufh can not be set by sysctl().
- */
-
-/* Per queue tunable limits */
-
-struct bufqlim {
-       blsize_t        bl_nlow;        /* minimum number of buffer headers required */
-       blsize_t        bl_num;         /* number of buffer headers on the queue */
-       blsize_t        bl_nlhigh;      /* maximum number of buffer headers allowed */
-       blsize_t        bl_target;      /* preferred number of buffer headers */
-       long    bl_stale;       /* Seconds after which a buffer is considered stale */
-} bufqlim[BQUEUES];
-
-/*
- * assertions:
- *
- * 1.  0 <= bl_nlow <= bl_num <= bl_nlhigh
- * 2.  bl_nlhigh <= MAXNBUF
- * 3.  bufqlim[BQ_META].bl_nlow != 0
- * 4.  bufqlim[BQ_META].bl_nlow > (number of possible concurrent 
- *                                                                     file system IO operations)
- * 5.  bl_num can not be set by sysctl().
- * 6.  bl_nhigh <= nbufhigh
- */
-
-/*
- * Rationale:
- * ----------
- * Defining it blsize_t as long permits 2^31 buffer headers per queue.
- * Which can describe (2^31 * PAGE_SIZE) memory per queue.
- * 
- * These limits are exported to by means of sysctl().
- * It was decided to define blsize_t as a 64 bit quantity.
- * This will make sure that we will not be required to change it
- * as long as we do not exceed 64 bit address space for the kernel.
- * 
- * low and high numbers parameters initialized at compile time
- * and boot arguments can be used to override them. sysctl() 
- * would not change the value. sysctl() can get all the values 
- * but can set only target. num is the current level.
- *
- * Advantages of having a "bufqscan" thread doing the balancing are, 
- * Keep enough bufs on BQ_EMPTY.
- *     getnewbuf() by default will always select a buffer from the BQ_EMPTY.
- *             getnewbuf() perfoms best if a buffer was found there.
- *             Also this minimizes the possibility of starting IO
- *             from getnewbuf(). That's a performance win, too.
- *
- *     Localize complex logic [balancing as well as time aging]
- *             to balancebufq().
- *
- *     Simplify getnewbuf() logic by elimination of time aging code.
- */
-
-/* 
- * Algorithm:
- * -----------
- * The goal of the dynamic scaling of the buffer queues to to keep
- * the size of the LRU close to bl_target. Buffers on a queue would
- * be time aged.
- *
- * There would be a thread which will be responsible for "balancing"
- * the buffer cache queues.
- *
- * The scan order would be:    AGE, LRU, META, EMPTY.
- */
-
-long bufqscanwait = 0;
-
-static void bufqscan_thread();
-static int balancebufq(int q);
-static int btrimempty(int n);
-static __inline__ int initbufqscan(void);
-static __inline__ int nextbufq(int q);
-static void buqlimprt(int all);
-
-
-static __inline__ void
-bufqinc(int q)
-{
-       if ((q < 0) || (q >= BQUEUES))
-               return;
-
-       bufqlim[q].bl_num++;
-       return;
-}
-
-static __inline__ void
-bufqdec(int q)
-{
-       if ((q < 0) || (q >= BQUEUES))
-               return; 
-
-       bufqlim[q].bl_num--;
-       return;
-}
-
-static void
-bufq_balance_thread_init()
-{
-
-       if (bufqscanwait++ == 0) {
-
-               /* Initalize globals */
-               MAXNBUF = (sane_size / PAGE_SIZE);
-               nbufh = nbuf;
-               nbuflow = min(nbufh, 100);
-               nbufhigh = min(MAXNBUF, max(nbufh, 2048));
-               nbuftarget = (sane_size >> 5) / PAGE_SIZE;
-               nbuftarget = max(nbuflow, nbuftarget);
-               nbuftarget = min(nbufhigh, nbuftarget);
-
-               /*
-                * Initialize the bufqlim 
-                */ 
-
-               /* LOCKED queue */
-               bufqlim[BQ_LOCKED].bl_nlow = 0;
-               bufqlim[BQ_LOCKED].bl_nlhigh = 32;
-               bufqlim[BQ_LOCKED].bl_target = 0;
-               bufqlim[BQ_LOCKED].bl_stale = 30;
-
-               /* LRU queue */
-               bufqlim[BQ_LRU].bl_nlow = 0;
-               bufqlim[BQ_LRU].bl_nlhigh = nbufhigh/4;
-               bufqlim[BQ_LRU].bl_target = nbuftarget/4;
-               bufqlim[BQ_LRU].bl_stale = LRU_IS_STALE;
-
-               /* AGE queue */
-               bufqlim[BQ_AGE].bl_nlow = 0;
-               bufqlim[BQ_AGE].bl_nlhigh = nbufhigh/4;
-               bufqlim[BQ_AGE].bl_target = nbuftarget/4;
-               bufqlim[BQ_AGE].bl_stale = AGE_IS_STALE;
-
-               /* EMPTY queue */
-               bufqlim[BQ_EMPTY].bl_nlow = 0;
-               bufqlim[BQ_EMPTY].bl_nlhigh = nbufhigh/4;
-               bufqlim[BQ_EMPTY].bl_target = nbuftarget/4;
-               bufqlim[BQ_EMPTY].bl_stale = 600000;
-
-               /* META queue */
-               bufqlim[BQ_META].bl_nlow = 0;
-               bufqlim[BQ_META].bl_nlhigh = nbufhigh/4;
-               bufqlim[BQ_META].bl_target = nbuftarget/4;
-               bufqlim[BQ_META].bl_stale = META_IS_STALE;
-
-               /* LAUNDRY queue */
-               bufqlim[BQ_LOCKED].bl_nlow = 0;
-               bufqlim[BQ_LOCKED].bl_nlhigh = 32;
-               bufqlim[BQ_LOCKED].bl_target = 0;
-               bufqlim[BQ_LOCKED].bl_stale = 30;
-
-               buqlimprt(1);
-       }
-
-       /* create worker thread */
-       kernel_thread(kernel_task, bufqscan_thread);
-}
-
-/* The workloop for the buffer balancing thread */
-static void
-bufqscan_thread()
-{
-       int moretodo = 0;
-
-       for(;;) {
-               do {
-                       int q;  /* buffer queue to process */
-               
-                       q = initbufqscan();
-                       for (; q; ) {
-                               moretodo |= balancebufq(q);
-                               q = nextbufq(q);
-                       }
-               } while (moretodo);
-
-#if DIAGNOSTIC
-               vfs_bufstats();
-               buqlimprt(0);
-#endif
-               (void)tsleep((void *)&bufqscanwait, PRIBIO, "bufqscanwait", 60 * hz);
-               moretodo = 0;
-       }
-}
-
-/* Seed for the buffer queue balancing */
-static __inline__ int
-initbufqscan()
-{
-       /* Start with AGE queue */
-       return (BQ_AGE);
-}
-
-/* Pick next buffer queue to balance */
-static __inline__ int
-nextbufq(int q)
-{
-       int order[] = { BQ_AGE, BQ_LRU, BQ_META, BQ_EMPTY, 0 };
-       
-       q++;
-       q %= sizeof(order);
-       return (order[q]);
-}
-
-/* function to balance the buffer queues */
-static int
-balancebufq(int q)
-{
-       int moretodo = 0;
-       int s = splbio();
-       int n, t;
-       
-       /* reject invalid q */
-       if ((q < 0) || (q >= BQUEUES))
-               goto out;
-
-       /* LOCKED or LAUNDRY queue MUST not be balanced */
-       if ((q == BQ_LOCKED) || (q == BQ_LAUNDRY))
-               goto out;
-
-       n = (bufqlim[q].bl_num - bufqlim[q].bl_target);
-
-       /* If queue has less than target nothing more to do */
-       if (n < 0)
-               goto out;
-
-       if ( n > 8 ) {
-               /* Balance only a small amount (12.5%) at a time */
-               n >>= 3;
-       }
-
-       /* EMPTY queue needs special handling */
-       if (q == BQ_EMPTY) {
-               moretodo |= btrimempty(n);
-               goto out;
-       }
-
-       t = buf_timestamp():
-       
-       for (; n > 0; n--) {
-               struct buf *bp = bufqueues[q].tqh_first;
-               if (!bp)
-                       break;
-               
-               /* check if it's stale */
-               if ((t - bp->b_timestamp) > bufqlim[q].bl_stale) {
-                       if (bcleanbuf(bp)) {
-                               /* buf_bawrite() issued, bp not ready */
-                               moretodo = 1;
-                       } else {
-                               /* release the cleaned buffer to BQ_EMPTY */
-                               SET(bp->b_flags, B_INVAL);
-                               buf_brelse(bp);
-                       }
-               } else
-                       break;          
-       }
-
-out:
-       splx(s);
-       return (moretodo);              
-}
-
-static int
-btrimempty(int n)
-{
-       /*
-        * When struct buf are allocated dynamically, this would
-        * reclaim upto 'n' struct buf from the empty queue.
-        */
-        
-        return (0);
-}
-
-static void
-buqlimprt(int all)
-{
-       int i;
-    static char *bname[BQUEUES] =
-               { "LOCKED", "LRU", "AGE", "EMPTY", "META", "LAUNDRY" };
-
-       if (all)
-               for (i = 0; i < BQUEUES; i++) {
-                       printf("%s : ", bname[i]);
-                       printf("min = %ld, ", (long)bufqlim[i].bl_nlow);
-                       printf("cur = %ld, ", (long)bufqlim[i].bl_num);
-                       printf("max = %ld, ", (long)bufqlim[i].bl_nlhigh);
-                       printf("target = %ld, ", (long)bufqlim[i].bl_target);
-                       printf("stale after %ld seconds\n", bufqlim[i].bl_stale);
-               }
-       else
-               for (i = 0; i < BQUEUES; i++) {
-                       printf("%s : ", bname[i]);
-                       printf("cur = %ld, ", (long)bufqlim[i].bl_num);
-               }
-}
-
-#endif
-
-