]> git.saurik.com Git - apple/xnu.git/blobdiff - bsd/vfs/vfs_cluster.c
xnu-1699.22.81.tar.gz
[apple/xnu.git] / bsd / vfs / vfs_cluster.c
index 891852d2634f8f523a34e78563ca138d4ee61cd3..0e8bd67ddabfb1fa4b9550f12a700defd50730ea 100644 (file)
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2000-2007 Apple Inc. All rights reserved.
+ * Copyright (c) 2000-2008 Apple Inc. All rights reserved.
  *
  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
  * 
 #include <mach/memory_object_types.h>
 #include <mach/vm_map.h>
 #include <mach/upl.h>
+#include <kern/task.h>
 
 #include <vm/vm_kern.h>
 #include <vm/vm_map.h>
 #include <vm/vm_pageout.h>
 
 #include <sys/kdebug.h>
+#include <libkern/OSAtomic.h>  
+
+#include <sys/sdt.h>
+
+#if 0
+#undef KERNEL_DEBUG
+#define KERNEL_DEBUG KERNEL_DEBUG_CONSTANT
+#endif
+
 
 #define CL_READ                0x01
-#define CL_WRITE               0x02
+#define CL_WRITE       0x02
 #define CL_ASYNC       0x04
 #define CL_COMMIT      0x08
 #define CL_PAGEOUT     0x10
 #define CL_KEEPCACHED  0x800
 #define CL_DIRECT_IO   0x1000
 #define CL_PASSIVE     0x2000
+#define CL_IOSTREAMING 0x4000
+#define CL_CLOSE       0x8000
+#define        CL_ENCRYPTED    0x10000
+
+#define MAX_VECTOR_UPL_ELEMENTS        8
+#define MAX_VECTOR_UPL_SIZE    (2 * MAX_UPL_SIZE) * PAGE_SIZE
 
+extern upl_t vector_upl_create(vm_offset_t);
+extern boolean_t vector_upl_is_valid(upl_t);
+extern boolean_t vector_upl_set_subupl(upl_t,upl_t, u_int32_t);
+extern void vector_upl_set_pagelist(upl_t);
+extern void vector_upl_set_iostate(upl_t, upl_t, vm_offset_t, u_int32_t);
 
 struct clios {
+       lck_mtx_t io_mtxp;
         u_int  io_completed;       /* amount of io that has currently completed */
         u_int  io_issued;          /* amount of io that was successfully issued */
         int    io_error;           /* error code of first error encountered */
@@ -115,7 +137,7 @@ struct clios {
 static lck_grp_t       *cl_mtx_grp;
 static lck_attr_t      *cl_mtx_attr;
 static lck_grp_attr_t   *cl_mtx_grp_attr;
-static lck_mtx_t       *cl_mtxp;
+static lck_mtx_t       *cl_transaction_mtxp;
 
 
 #define        IO_UNKNOWN      0
@@ -138,11 +160,13 @@ static int cluster_io(vnode_t vp, upl_t upl, vm_offset_t upl_offset, off_t f_off
                      int flags, buf_t real_bp, struct clios *iostate, int (*)(buf_t, void *), void *callback_arg);
 static int cluster_iodone(buf_t bp, void *callback_arg);
 static int cluster_ioerror(upl_t upl, int upl_offset, int abort_size, int error, int io_flags);
-static int cluster_hard_throttle_on(vnode_t vp);
+static int cluster_hard_throttle_on(vnode_t vp, uint32_t);
+
+static void cluster_iostate_wait(struct clios *iostate, u_int target, const char *wait_name);
 
 static void cluster_syncup(vnode_t vp, off_t newEOF, int (*)(buf_t, void *), void *callback_arg);
 
-static void cluster_read_upl_release(upl_t upl, int start_pg, int last_pg, int flags);
+static void cluster_read_upl_release(upl_t upl, int start_pg, int last_pg, int take_reference);
 static int cluster_copy_ubc_data_internal(vnode_t vp, struct uio *uio, int *io_resid, int mark_dirty, int take_reference);
 
 static int cluster_read_copy(vnode_t vp, struct uio *uio, u_int32_t io_req_size,  off_t filesize, int flags,
@@ -166,33 +190,40 @@ static void       cluster_read_ahead(vnode_t vp, struct cl_extent *extent, off_t files
 
 static int     cluster_push_now(vnode_t vp, struct cl_extent *, off_t EOF, int flags, int (*)(buf_t, void *), void *callback_arg);
 
-static int     cluster_try_push(struct cl_writebehind *, vnode_t vp, off_t EOF, int push_flag, int (*)(buf_t, void *), void *callback_arg);
+static int     cluster_try_push(struct cl_writebehind *, vnode_t vp, off_t EOF, int push_flag, int flags, int (*)(buf_t, void *), void *callback_arg);
 
 static void    sparse_cluster_switch(struct cl_writebehind *, vnode_t vp, off_t EOF, int (*)(buf_t, void *), void *callback_arg);
-static void    sparse_cluster_push(struct cl_writebehind *, vnode_t vp, off_t EOF, int push_flag, int (*)(buf_t, void *), void *callback_arg);
-static void    sparse_cluster_add(struct cl_writebehind *, vnode_t vp, struct cl_extent *, off_t EOF, int (*)(buf_t, void *), void *callback_arg);
+static void    sparse_cluster_push(void **cmapp, vnode_t vp, off_t EOF, int push_flag, int io_flags, int (*)(buf_t, void *), void *callback_arg);
+static void    sparse_cluster_add(void **cmapp, vnode_t vp, struct cl_extent *, off_t EOF, int (*)(buf_t, void *), void *callback_arg);
 
 static kern_return_t vfs_drt_mark_pages(void **cmapp, off_t offset, u_int length, u_int *setcountp);
 static kern_return_t vfs_drt_get_cluster(void **cmapp, off_t *offsetp, u_int *lengthp);
 static kern_return_t vfs_drt_control(void **cmapp, int op_type);
 
-int    is_file_clean(vnode_t, off_t);
 
 /*
  * limit the internal I/O size so that we
  * can represent it in a 32 bit int
  */
-#define MAX_IO_REQUEST_SIZE    (1024 * 1024 * 256)
-#define MAX_IO_CONTIG_SIZE             (MAX_UPL_SIZE * PAGE_SIZE)
-#define MAX_VECTS                      16
+#define MAX_IO_REQUEST_SIZE    (1024 * 1024 * 512)
+#define MAX_IO_CONTIG_SIZE     (MAX_UPL_SIZE * PAGE_SIZE)
+#define MAX_VECTS              16
 #define MIN_DIRECT_WRITE_SIZE  (4 * PAGE_SIZE)
 
+#define WRITE_THROTTLE         6
+#define WRITE_THROTTLE_SSD     2
+#define WRITE_BEHIND           1
+#define WRITE_BEHIND_SSD       1
+#define PREFETCH               3
+#define PREFETCH_SSD           2
 
-#define MAX_CLUSTER_SIZE(vp)   (cluster_max_io_size(vp->v_mount, CL_WRITE))
-#define MAX_PREFETCH(vp)       (cluster_max_io_size(vp->v_mount, CL_READ) * 3);
-
+#define IO_SCALE(vp, base)             (vp->v_mount->mnt_ioscale * base)
+#define MAX_CLUSTER_SIZE(vp)           (cluster_max_io_size(vp->v_mount, CL_WRITE))
+#define MAX_PREFETCH(vp, size, is_ssd) (size * IO_SCALE(vp, (is_ssd && !ignore_is_ssd) ? PREFETCH_SSD : PREFETCH))
 
-int speculative_reads_disabled = 0;
+int    ignore_is_ssd = 0;
+int    speculative_reads_disabled = 0;
+uint32_t speculative_prefetch_max = (MAX_UPL_SIZE * 3);
 
 /*
  * throttle the number of async writes that
@@ -200,7 +231,7 @@ int speculative_reads_disabled = 0;
  * before we issue a synchronous write 
  */
 #define HARD_THROTTLE_MAXCNT   0
-#define HARD_THROTTLE_MAXSIZE  (64 * 1024)
+#define HARD_THROTTLE_MAXSIZE  (32 * 1024)
 
 int hard_throttle_on_root = 0;
 struct timeval priority_IO_timestamp_for_root;
@@ -219,39 +250,35 @@ cluster_init(void) {
         */
        cl_mtx_attr = lck_attr_alloc_init();
 
-       /*
-        * allocate and initialize mutex's used to protect updates and waits
-        * on the cluster_io context
-        */
-       cl_mtxp = lck_mtx_alloc_init(cl_mtx_grp, cl_mtx_attr);
+       cl_transaction_mtxp = lck_mtx_alloc_init(cl_mtx_grp, cl_mtx_attr);
 
-       if (cl_mtxp == NULL)
-               panic("cluster_init: failed to allocate cl_mtxp");
+       if (cl_transaction_mtxp == NULL)
+               panic("cluster_init: failed to allocate cl_transaction_mtxp");
 }
 
 
 uint32_t
 cluster_max_io_size(mount_t mp, int type)
 {
-       uint32_t        max_io_size;
-       uint32_t        segcnt;
-       uint32_t        maxcnt;
-       switch(type) {
-
-       case CL_READ:
-               segcnt = mp->mnt_segreadcnt;
-               maxcnt = mp->mnt_maxreadcnt;
-               break;
-       case CL_WRITE:
-               segcnt = mp->mnt_segwritecnt;
-               maxcnt = mp->mnt_maxwritecnt;
-               break;
-       default:
-               segcnt = min(mp->mnt_segreadcnt, mp->mnt_segwritecnt);
-               maxcnt = min(mp->mnt_maxreadcnt, mp->mnt_maxwritecnt);
-               break;
-       }
+       uint32_t        max_io_size;
+       uint32_t        segcnt;
+       uint32_t        maxcnt;
+
+       switch(type) {
+
+       case CL_READ:
+               segcnt = mp->mnt_segreadcnt;
+               maxcnt = mp->mnt_maxreadcnt;
+               break;
+       case CL_WRITE:
+               segcnt = mp->mnt_segwritecnt;
+               maxcnt = mp->mnt_maxwritecnt;
+               break;
+       default:
+               segcnt = min(mp->mnt_segreadcnt, mp->mnt_segwritecnt);
+               maxcnt = min(mp->mnt_maxreadcnt, mp->mnt_maxwritecnt);
+               break;
+       }
        if (segcnt > MAX_UPL_SIZE) {
               /*
                * don't allow a size beyond the max UPL size we can create
@@ -391,7 +418,7 @@ cluster_syncup(vnode_t vp, off_t newEOF, int (*callback)(buf_t, void *), void *c
                if (wbp->cl_number) {
                        lck_mtx_lock(&wbp->cl_lockw);
 
-                       cluster_try_push(wbp, vp, newEOF, PUSH_ALL | PUSH_SYNC, callback, callback_arg);
+                       cluster_try_push(wbp, vp, newEOF, PUSH_ALL | PUSH_SYNC, 0, callback, callback_arg);
 
                        lck_mtx_unlock(&wbp->cl_lockw);
                }
@@ -400,26 +427,56 @@ cluster_syncup(vnode_t vp, off_t newEOF, int (*callback)(buf_t, void *), void *c
 
 
 static int 
-cluster_hard_throttle_on(vnode_t vp)
+cluster_hard_throttle_on(vnode_t vp, uint32_t hard_throttle)
 {
-        static struct timeval hard_throttle_maxelapsed = { 0, 200000 };
+       struct uthread  *ut;
 
-       if (vp->v_mount->mnt_kern_flag & MNTK_ROOTDEV) {
-               struct timeval elapsed;
+       if (hard_throttle) {
+               static struct timeval hard_throttle_maxelapsed = { 0, 200000 };
 
-               if (hard_throttle_on_root)
-                       return(1);
+               if (vp->v_mount->mnt_kern_flag & MNTK_ROOTDEV) {
+                       struct timeval elapsed;
 
-               microuptime(&elapsed);
-               timevalsub(&elapsed, &priority_IO_timestamp_for_root);
+                       if (hard_throttle_on_root)
+                               return(1);
 
-               if (timevalcmp(&elapsed, &hard_throttle_maxelapsed, <))
-                       return(1);
+                       microuptime(&elapsed);
+                       timevalsub(&elapsed, &priority_IO_timestamp_for_root);
+
+                       if (timevalcmp(&elapsed, &hard_throttle_maxelapsed, <))
+                               return(1);
+               }
+       }
+       if (throttle_get_io_policy(&ut) == IOPOL_THROTTLE) {
+               if (throttle_io_will_be_throttled(-1, vp->v_mount)) {
+                       return(1);
+               }
        }
        return(0);
 }
 
 
+static void
+cluster_iostate_wait(struct clios *iostate, u_int target, const char *wait_name)
+{
+
+       lck_mtx_lock(&iostate->io_mtxp);
+
+       while ((iostate->io_issued - iostate->io_completed) > target) {
+
+               KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 95)) | DBG_FUNC_START,
+                            iostate->io_issued, iostate->io_completed, target, 0, 0);
+
+               iostate->io_wanted = 1;
+               msleep((caddr_t)&iostate->io_wanted, &iostate->io_mtxp, PRIBIO + 1, wait_name, NULL);
+
+               KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 95)) | DBG_FUNC_END,
+                            iostate->io_issued, iostate->io_completed, target, 0, 0);
+       }       
+       lck_mtx_unlock(&iostate->io_mtxp);
+}
+
+
 static int
 cluster_ioerror(upl_t upl, int upl_offset, int abort_size, int error, int io_flags)
 {
@@ -427,7 +484,7 @@ cluster_ioerror(upl_t upl, int upl_offset, int abort_size, int error, int io_fla
        int page_in  = 0;
        int page_out = 0;
 
-       if (io_flags & B_PHYS)
+       if ((io_flags & (B_PHYS | B_CACHE)) == (B_PHYS | B_CACHE))
                /*
                 * direct write of any flavor, or a direct read that wasn't aligned
                 */
@@ -484,28 +541,49 @@ cluster_iodone(buf_t bp, void *callback_arg)
        cbp_head = (buf_t)(bp->b_trans_head);
 
        KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 20)) | DBG_FUNC_START,
-                    (int)cbp_head, bp->b_lblkno, bp->b_bcount, bp->b_flags, 0);
+                    cbp_head, bp->b_lblkno, bp->b_bcount, bp->b_flags, 0);
 
-       for (cbp = cbp_head; cbp; cbp = cbp->b_trans_next) {
-               /*
-                * all I/O requests that are part of this transaction
-                * have to complete before we can process it
-                */
-               if ( !(cbp->b_flags & B_DONE)) {
+       if (cbp_head->b_trans_next || !(cbp_head->b_flags & B_EOT)) {
+               boolean_t       need_wakeup = FALSE;
 
-                       KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 20)) | DBG_FUNC_END,
-                                    (int)cbp_head, (int)cbp, cbp->b_bcount, cbp->b_flags, 0);
+               lck_mtx_lock_spin(cl_transaction_mtxp);
 
-                       return 0;
+               bp->b_flags |= B_TDONE;
+               
+               if (bp->b_flags & B_TWANTED) {
+                       CLR(bp->b_flags, B_TWANTED);
+                       need_wakeup = TRUE;
                }
-               if (cbp->b_flags & B_EOT)
-                       transaction_complete = TRUE;
-       }
-       if (transaction_complete == FALSE) {
-               KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 20)) | DBG_FUNC_END,
-                            (int)cbp_head, 0, 0, 0, 0);
+               for (cbp = cbp_head; cbp; cbp = cbp->b_trans_next) {
+                       /*
+                        * all I/O requests that are part of this transaction
+                        * have to complete before we can process it
+                        */
+                       if ( !(cbp->b_flags & B_TDONE)) {
+
+                               KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 20)) | DBG_FUNC_END,
+                                            cbp_head, cbp, cbp->b_bcount, cbp->b_flags, 0);
+
+                               lck_mtx_unlock(cl_transaction_mtxp);
+
+                               if (need_wakeup == TRUE)
+                                       wakeup(bp);
+
+                               return 0;
+                       }
+                       if (cbp->b_flags & B_EOT)
+                               transaction_complete = TRUE;
+               }
+               lck_mtx_unlock(cl_transaction_mtxp);
+
+               if (need_wakeup == TRUE)
+                       wakeup(bp);
 
-               return 0;
+               if (transaction_complete == FALSE) {
+                       KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 20)) | DBG_FUNC_END,
+                                    cbp_head, 0, 0, 0, 0);
+                       return 0;
+               }
        }
        error       = 0;
        total_size  = 0;
@@ -569,7 +647,7 @@ cluster_iodone(buf_t bp, void *callback_arg)
                 * someone has issued multiple I/Os asynchrounsly
                 * and is waiting for them to complete (streaming)
                 */
-               lck_mtx_lock_spin(cl_mtxp);
+               lck_mtx_lock_spin(&iostate->io_mtxp);
 
                if (error && iostate->io_error == 0)
                        iostate->io_error = error;
@@ -584,7 +662,7 @@ cluster_iodone(buf_t bp, void *callback_arg)
                        iostate->io_wanted = 0;
                        need_wakeup = 1;
                }
-               lck_mtx_unlock(cl_mtxp);
+               lck_mtx_unlock(&iostate->io_mtxp);
 
                if (need_wakeup)
                        wakeup((caddr_t)&iostate->io_wanted);
@@ -609,7 +687,7 @@ cluster_iodone(buf_t bp, void *callback_arg)
                        ubc_upl_commit_range(upl, upl_offset - pg_offset, commit_size, upl_flags);
                }
        }
-       if ((b_flags & B_NEED_IODONE) && real_bp) {
+       if (real_bp) {
                if (error) {
                        real_bp->b_flags |= B_ERROR;
                        real_bp->b_error = error;
@@ -619,18 +697,29 @@ cluster_iodone(buf_t bp, void *callback_arg)
                buf_biodone(real_bp);
        }
        KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 20)) | DBG_FUNC_END,
-                    (int)upl, upl_offset - pg_offset, commit_size, (error << 24) | upl_flags, 0);
+                    upl, upl_offset - pg_offset, commit_size, (error << 24) | upl_flags, 0);
 
        return (error);
 }
 
 
+uint32_t
+cluster_hard_throttle_limit(vnode_t vp, uint32_t *limit, uint32_t hard_throttle)
+{
+       if (cluster_hard_throttle_on(vp, hard_throttle)) {
+               *limit = HARD_THROTTLE_MAXSIZE;
+               return 1;
+       }
+       return 0;   
+}
+
+
 void
-cluster_zero(upl_t upl, vm_offset_t upl_offset, int size, buf_t bp)
+cluster_zero(upl_t upl, upl_offset_t upl_offset, int size, buf_t bp)
 {
 
        KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 23)) | DBG_FUNC_START,
-                    upl_offset, size, (int)bp, 0, 0);
+                    upl_offset, size, bp, 0, 0);
 
        if (bp == NULL || bp->b_datap == 0) {
                upl_page_info_t *pl;
@@ -684,27 +773,36 @@ cluster_wait_IO(buf_t cbp_head, int async)
                /*
                 * async callback completion will not normally
                 * generate a wakeup upon I/O completion...
-                * by setting BL_WANTED, we will force a wakeup
+                * by setting B_TWANTED, we will force a wakeup
                 * to occur as any outstanding I/Os complete... 
-                * I/Os already completed will have BL_CALLDONE already
-                * set and we won't block in buf_biowait_callback..
+                * I/Os already completed will have B_TDONE already
+                * set and we won't cause us to block
                 * note that we're actually waiting for the bp to have
                 * completed the callback function... only then
                 * can we safely take back ownership of the bp
-                * need the main buf mutex in order to safely
-                * update b_lflags
                 */
-               buf_list_lock();
+               lck_mtx_lock_spin(cl_transaction_mtxp);
 
                for (cbp = cbp_head; cbp; cbp = cbp->b_trans_next)
-                     cbp->b_lflags |= BL_WANTED;
+                     cbp->b_flags |= B_TWANTED;
 
-               buf_list_unlock();
+               lck_mtx_unlock(cl_transaction_mtxp);
        }
        for (cbp = cbp_head; cbp; cbp = cbp->b_trans_next) {
-               if (async)
-                       buf_biowait_callback(cbp);
-               else
+
+               if (async) {
+                       while (!ISSET(cbp->b_flags, B_TDONE)) {
+
+                               lck_mtx_lock_spin(cl_transaction_mtxp);
+
+                               if (!ISSET(cbp->b_flags, B_TDONE)) {
+                                       DTRACE_IO1(wait__start, buf_t, cbp);
+                                       (void) msleep(cbp, cl_transaction_mtxp, PDROP | (PRIBIO+1), "cluster_wait_IO", NULL);
+                                       DTRACE_IO1(wait__done, buf_t, cbp);
+                               } else
+                                       lck_mtx_unlock(cl_transaction_mtxp);
+                       }
+               } else
                        buf_biowait(cbp);
        }
 }
@@ -724,6 +822,14 @@ cluster_complete_transaction(buf_t *cbp_head, void *callback_arg, int *retval, i
                for (cbp = *cbp_head; cbp; cbp = cbp->b_trans_next)
                        buf_biowait(cbp);
        }
+       /*
+        * we've already waited on all of the I/Os in this transaction,
+        * so mark all of the buf_t's in this transaction as B_TDONE
+        * so that cluster_iodone sees the transaction as completed
+        */
+       for (cbp = *cbp_head; cbp; cbp = cbp->b_trans_next)
+               cbp->b_flags |= B_TDONE;
+
        error = cluster_iodone(*cbp_head, callback_arg);
 
        if ( !(flags & CL_ASYNC) && error && *retval == 0) {
@@ -841,30 +947,37 @@ cluster_io(vnode_t vp, upl_t upl, vm_offset_t upl_offset, off_t f_offset, int no
                max_iosize = PAGE_SIZE;
 
        if (flags & CL_THROTTLE) {
-               if ( !(flags & CL_PAGEOUT) && cluster_hard_throttle_on(vp)) {
+               if ( !(flags & CL_PAGEOUT) && cluster_hard_throttle_on(vp, 1)) {
                        if (max_iosize > HARD_THROTTLE_MAXSIZE)
                                max_iosize = HARD_THROTTLE_MAXSIZE;
                        async_throttle = HARD_THROTTLE_MAXCNT;
                } else {
                        if ( (flags & CL_DEV_MEMORY) )
-                               async_throttle = VNODE_ASYNC_THROTTLE;
+                               async_throttle = IO_SCALE(vp, VNODE_ASYNC_THROTTLE);
                        else {
                                u_int max_cluster;
                                u_int max_cluster_size;
-                               u_int max_prefetch;
+                               u_int scale;
 
                                max_cluster_size = MAX_CLUSTER_SIZE(vp);
-                               max_prefetch = MAX_PREFETCH(vp);
-                               
+
                                if (max_iosize > max_cluster_size)
-                                       max_cluster = max_cluster_size;
+                                       max_cluster = max_cluster_size;
                                else
                                        max_cluster = max_iosize;
 
                                if (size < max_cluster)
                                        max_cluster = size;
+                               
+                               if ((vp->v_mount->mnt_kern_flag & MNTK_SSD) && !ignore_is_ssd)
+                                       scale = WRITE_THROTTLE_SSD;
+                               else
+                                       scale = WRITE_THROTTLE;
+
+                               if (flags & CL_CLOSE)
+                                       scale += MAX_CLUSTERS;
 
-                               async_throttle = min(VNODE_ASYNC_THROTTLE, (max_prefetch / max_cluster) - 1);
+                               async_throttle = min(IO_SCALE(vp, VNODE_ASYNC_THROTTLE), ((scale * max_cluster_size) / max_cluster) - 1);
                        }
                }
        }
@@ -872,14 +985,18 @@ cluster_io(vnode_t vp, upl_t upl, vm_offset_t upl_offset, off_t f_offset, int no
                io_flags |= B_AGE;
        if (flags & (CL_PAGEIN | CL_PAGEOUT))
                io_flags |= B_PAGEIO;
+       if (flags & (CL_IOSTREAMING))
+               io_flags |= B_IOSTREAMING;
        if (flags & CL_COMMIT)
                io_flags |= B_COMMIT_UPL;
-       if (flags & CL_PRESERVE)
+       if (flags & CL_DIRECT_IO)
                io_flags |= B_PHYS;
-       if (flags & CL_KEEPCACHED)
-               io_flags |= B_CACHE;
+       if (flags & (CL_PRESERVE | CL_KEEPCACHED))
+               io_flags |= B_CACHE;
        if (flags & CL_PASSIVE)
                io_flags |= B_PASSIVE;
+       if (flags & CL_ENCRYPTED)
+               io_flags |= B_ENCRYPTED_IO;     
        if (vp->v_flag & VSYSTEM)
                io_flags |= B_META;
 
@@ -897,6 +1014,7 @@ cluster_io(vnode_t vp, upl_t upl, vm_offset_t upl_offset, off_t f_offset, int no
                daddr64_t blkno;
                daddr64_t lblkno;
                u_int   io_size_wanted;
+               size_t  io_size_tmp;
 
                if (size > max_iosize)
                        io_size = max_iosize;
@@ -904,12 +1022,15 @@ cluster_io(vnode_t vp, upl_t upl, vm_offset_t upl_offset, off_t f_offset, int no
                        io_size = size;
 
                io_size_wanted = io_size;
+               io_size_tmp = (size_t)io_size;
                
-               if ((error = VNOP_BLOCKMAP(vp, f_offset, io_size, &blkno, (size_t *)&io_size, NULL, bmap_flags, NULL)))
+               if ((error = VNOP_BLOCKMAP(vp, f_offset, io_size, &blkno, &io_size_tmp, NULL, bmap_flags, NULL)))
                        break;
 
-               if (io_size > io_size_wanted)
+               if (io_size_tmp > io_size_wanted)
                        io_size = io_size_wanted;
+               else
+                       io_size = (u_int)io_size_tmp;
 
                if (real_bp && (real_bp->b_blkno == real_bp->b_lblkno))
                        real_bp->b_blkno = blkno;
@@ -932,6 +1053,8 @@ cluster_io(vnode_t vp, upl_t upl, vm_offset_t upl_offset, off_t f_offset, int no
                        off_t   e_offset;
                        int     pageout_flags;
 
+                       if (upl_get_internal_vectorupl(upl))
+                               panic("Vector UPLs should not take this code-path\n");
                        /*
                         * we're writing into a 'hole'
                         */
@@ -1037,7 +1160,6 @@ cluster_io(vnode_t vp, upl_t upl, vm_offset_t upl_offset, off_t f_offset, int no
                        }
                        if (vnode_pageout(vp, upl, trunc_page(upl_offset), trunc_page_64(f_offset), PAGE_SIZE, pageout_flags, NULL) != PAGER_SUCCESS) {
                                error = EINVAL;
-                               break;
                        }
                        e_offset = round_page_64(f_offset + 1);
                        io_size = e_offset - f_offset;
@@ -1066,6 +1188,11 @@ cluster_io(vnode_t vp, upl_t upl, vm_offset_t upl_offset, off_t f_offset, int no
                                 */
                                size = 0;
                        }
+                       if (error) {
+                               if (size == 0)
+                                       flags &= ~CL_COMMIT;
+                               break;
+                       }
                        continue;
                }
                lblkno = (daddr64_t)(f_offset / PAGE_SIZE_64);
@@ -1303,10 +1430,8 @@ cluster_io(vnode_t vp, upl_t upl, vm_offset_t upl_offset, off_t f_offset, int no
                        cbp_head = cbp;
                        cbp_tail = cbp;
 
-                       if ( (cbp_head->b_real_bp = real_bp) ) {
-                               cbp_head->b_flags |= B_NEED_IODONE;
+                       if ( (cbp_head->b_real_bp = real_bp) )
                                real_bp = (buf_t)NULL;
-                       }
                }
                *(buf_t *)(&cbp->b_trans_head) = cbp_head;
 
@@ -1412,7 +1537,7 @@ cluster_io(vnode_t vp, upl_t upl, vm_offset_t upl_offset, off_t f_offset, int no
                         * since we never really issued the io
                         * just go ahead and adjust it back
                         */
-                       lck_mtx_lock_spin(cl_mtxp);
+                       lck_mtx_lock_spin(&iostate->io_mtxp);
 
                        if (iostate->io_error == 0)
                                iostate->io_error = error;
@@ -1426,7 +1551,7 @@ cluster_io(vnode_t vp, upl_t upl, vm_offset_t upl_offset, off_t f_offset, int no
                                iostate->io_wanted = 0;
                                need_wakeup = 1;
                        }
-                       lck_mtx_unlock(cl_mtxp);
+                       lck_mtx_unlock(&iostate->io_mtxp);
 
                        if (need_wakeup)
                                wakeup((caddr_t)&iostate->io_wanted);
@@ -1440,7 +1565,7 @@ cluster_io(vnode_t vp, upl_t upl, vm_offset_t upl_offset, off_t f_offset, int no
                        upl_flags = cluster_ioerror(upl, upl_offset - pg_offset, abort_size, error, io_flags);
                        
                        KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 28)) | DBG_FUNC_NONE,
-                                    (int)upl, upl_offset - pg_offset, abort_size, (error << 24) | upl_flags, 0);
+                                    upl, upl_offset - pg_offset, abort_size, (error << 24) | upl_flags, 0);
                }
                if (retval == 0)
                        retval = error;
@@ -1464,6 +1589,24 @@ cluster_io(vnode_t vp, upl_t upl, vm_offset_t upl_offset, off_t f_offset, int no
        return (retval);
 }
 
+#define reset_vector_run_state()                                                                               \
+       issueVectorUPL = vector_upl_offset = vector_upl_index = vector_upl_iosize = vector_upl_size = 0;        
+
+static int
+vector_cluster_io(vnode_t vp, upl_t vector_upl, vm_offset_t vector_upl_offset, off_t v_upl_uio_offset, int vector_upl_iosize,
+          int io_flag, buf_t real_bp, struct clios *iostate, int (*callback)(buf_t, void *), void *callback_arg)
+{
+       vector_upl_set_pagelist(vector_upl);
+
+       if(io_flag & CL_READ) { 
+               if(vector_upl_offset == 0 && ((vector_upl_iosize & PAGE_MASK)==0))
+                               io_flag &= ~CL_PRESERVE; /*don't zero fill*/
+               else
+                               io_flag |= CL_PRESERVE; /*zero fill*/
+       }       
+       return (cluster_io(vp, vector_upl, vector_upl_offset, v_upl_uio_offset, vector_upl_iosize, io_flag, real_bp, iostate, callback, callback_arg));
+
+}
 
 static int
 cluster_read_prefetch(vnode_t vp, off_t f_offset, u_int size, off_t filesize, int (*callback)(buf_t, void *), void *callback_arg, int bflag)
@@ -1499,7 +1642,7 @@ cluster_read_ahead(vnode_t vp, struct cl_extent *extent, off_t filesize, struct
        daddr64_t       r_addr;
        off_t           f_offset;
        int             size_of_prefetch;
-       u_int           max_prefetch;
+       u_int           max_prefetch;
 
 
        KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 48)) | DBG_FUNC_START,
@@ -1519,8 +1662,16 @@ cluster_read_ahead(vnode_t vp, struct cl_extent *extent, off_t filesize, struct
 
                return;
        }
-       max_prefetch = MAX_PREFETCH(vp);
+       max_prefetch = MAX_PREFETCH(vp, cluster_max_io_size(vp->v_mount, CL_READ), (vp->v_mount->mnt_kern_flag & MNTK_SSD));
 
+       if ((max_prefetch / PAGE_SIZE) > speculative_prefetch_max)
+               max_prefetch = (speculative_prefetch_max * PAGE_SIZE);
+
+       if (max_prefetch <= PAGE_SIZE) {
+               KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 48)) | DBG_FUNC_END,
+                            rap->cl_ralen, (int)rap->cl_maxra, (int)rap->cl_lastr, 6, 0);
+               return;
+       }
        if (extent->e_addr < rap->cl_maxra) {
                if ((rap->cl_maxra - extent->e_addr) > ((max_prefetch / PAGE_SIZE) / 4)) {
 
@@ -1565,7 +1716,7 @@ cluster_read_ahead(vnode_t vp, struct cl_extent *extent, off_t filesize, struct
 
 
 int
-cluster_pageout(vnode_t vp, upl_t upl, vm_offset_t upl_offset, off_t f_offset,
+cluster_pageout(vnode_t vp, upl_t upl, upl_offset_t upl_offset, off_t f_offset,
                int size, off_t filesize, int flags)
 {
         return cluster_pageout_ext(vp, upl, upl_offset, f_offset, size, filesize, flags, NULL, NULL);
@@ -1574,7 +1725,7 @@ cluster_pageout(vnode_t vp, upl_t upl, vm_offset_t upl_offset, off_t f_offset,
 
 
 int
-cluster_pageout_ext(vnode_t vp, upl_t upl, vm_offset_t upl_offset, off_t f_offset,
+cluster_pageout_ext(vnode_t vp, upl_t upl, upl_offset_t upl_offset, off_t f_offset,
                int size, off_t filesize, int flags, int (*callback)(buf_t, void *), void *callback_arg)
 {
        int           io_size;
@@ -1582,18 +1733,7 @@ cluster_pageout_ext(vnode_t vp, upl_t upl, vm_offset_t upl_offset, off_t f_offse
         off_t         max_size;
        int           local_flags;
 
-       if (vp->v_mount->mnt_kern_flag & MNTK_VIRTUALDEV)
-               /*
-                * if we know we're issuing this I/O to a virtual device (i.e. disk image)
-                * then we don't want to enforce this throttle... if we do, we can 
-                * potentially deadlock since we're stalling the pageout thread at a time
-                * when the disk image might need additional memory (which won't be available
-                * if the pageout thread can't run)... instead we'll just depend on the throttle
-                * that the pageout thread now has in place to deal with external files
-                */
-               local_flags = CL_PAGEOUT;
-       else
-               local_flags = CL_PAGEOUT | CL_THROTTLE;
+       local_flags = CL_PAGEOUT | CL_THROTTLE;
 
        if ((flags & UPL_IOSYNC) == 0) 
                local_flags |= CL_ASYNC;
@@ -1601,8 +1741,8 @@ cluster_pageout_ext(vnode_t vp, upl_t upl, vm_offset_t upl_offset, off_t f_offse
                local_flags |= CL_COMMIT;
        if ((flags & UPL_KEEPCACHED))
                local_flags |= CL_KEEPCACHED;
-       if (flags & IO_PASSIVE) 
-               local_flags |= CL_PASSIVE;
+       if (flags & UPL_PAGING_ENCRYPTED)
+               local_flags |= CL_ENCRYPTED;
 
 
        KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 52)) | DBG_FUNC_NONE,
@@ -1653,7 +1793,7 @@ cluster_pageout_ext(vnode_t vp, upl_t upl, vm_offset_t upl_offset, off_t f_offse
 
 
 int
-cluster_pagein(vnode_t vp, upl_t upl, vm_offset_t upl_offset, off_t f_offset,
+cluster_pagein(vnode_t vp, upl_t upl, upl_offset_t upl_offset, off_t f_offset,
               int size, off_t filesize, int flags)
 {
         return cluster_pagein_ext(vp, upl, upl_offset, f_offset, size, filesize, flags, NULL, NULL);
@@ -1661,7 +1801,7 @@ cluster_pagein(vnode_t vp, upl_t upl, vm_offset_t upl_offset, off_t f_offset,
 
 
 int
-cluster_pagein_ext(vnode_t vp, upl_t upl, vm_offset_t upl_offset, off_t f_offset,
+cluster_pagein_ext(vnode_t vp, upl_t upl, upl_offset_t upl_offset, off_t f_offset,
               int size, off_t filesize, int flags, int (*callback)(buf_t, void *), void *callback_arg)
 {
        u_int         io_size;
@@ -1677,8 +1817,10 @@ cluster_pagein_ext(vnode_t vp, upl_t upl, vm_offset_t upl_offset, off_t f_offset
                local_flags |= CL_ASYNC;
        if ((flags & UPL_NOCOMMIT) == 0) 
                local_flags |= CL_COMMIT;
-       if (flags & IO_PASSIVE) 
-               local_flags |= CL_PASSIVE;
+       if (flags & UPL_IOSTREAMING)
+               local_flags |= CL_IOSTREAMING;
+       if (flags & UPL_PAGING_ENCRYPTED)
+               local_flags |= CL_ENCRYPTED;
 
 
        KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 56)) | DBG_FUNC_NONE,
@@ -1730,7 +1872,7 @@ cluster_bp_ext(buf_t bp, int (*callback)(buf_t, void *), void *callback_arg)
        int    flags;
 
        KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 19)) | DBG_FUNC_START,
-                    (int)bp, (int)bp->b_lblkno, bp->b_bcount, bp->b_flags, 0);
+                    bp, (int)bp->b_lblkno, bp->b_bcount, bp->b_flags, 0);
 
        if (bp->b_flags & B_READ)
                flags = CL_ASYNC | CL_READ;
@@ -1768,9 +1910,9 @@ cluster_write_ext(vnode_t vp, struct uio *uio, off_t oldEOF, off_t newEOF, off_t
        flags = xflags;
 
        if (flags & IO_PASSIVE)
-           bflag = CL_PASSIVE;
+               bflag = CL_PASSIVE;
        else
-           bflag = 0;
+               bflag = 0;
 
        if (vp->v_flag & VNOCACHE_DATA)
                flags |= IO_NOCACHE;
@@ -1786,12 +1928,12 @@ cluster_write_ext(vnode_t vp, struct uio *uio, off_t oldEOF, off_t newEOF, off_t
        }
         /*
          * do a write through the cache if one of the following is true....
-         *   NOCACHE is not true and
+         *   NOCACHE is not true or NODIRECT is true
          *   the uio request doesn't target USERSPACE
          * otherwise, find out if we want the direct or contig variant for
          * the first vector in the uio request
          */
-        if ( (flags & IO_NOCACHE) && UIO_SEG_IS_USER_SPACE(uio->uio_segflg) )
+       if ( ((flags & (IO_NOCACHE | IO_NODIRECT)) == IO_NOCACHE) && UIO_SEG_IS_USER_SPACE(uio->uio_segflg) )
                retval = cluster_io_type(uio, &write_type, &write_length, MIN_DIRECT_WRITE_SIZE);
 
         if ( (flags & (IO_TAILZEROFILL | IO_HEADZEROFILL)) && write_type == IO_DIRECT)
@@ -1873,6 +2015,18 @@ cluster_write_ext(vnode_t vp, struct uio *uio, off_t oldEOF, off_t newEOF, off_t
                        retval = cluster_io_type(uio, &write_type, &write_length, MIN_DIRECT_WRITE_SIZE);
                        break;
                }
+               /*
+                * in case we end up calling cluster_write_copy (from cluster_write_direct)
+                * multiple times to service a multi-vector request that is not aligned properly
+                * we need to update the oldEOF so that we
+                * don't zero-fill the head of a page if we've successfully written
+                * data to that area... 'cluster_write_copy' will zero-fill the head of a
+                * page that is beyond the oldEOF if the write is unaligned... we only
+                * want that to happen for the very first page of the cluster_write, 
+                * NOT the first page of each vector making up a multi-vector write.
+                */
+               if (uio->uio_offset > oldEOF)
+                       oldEOF = uio->uio_offset;
        }
        return (retval);
 }
@@ -1885,13 +2039,13 @@ cluster_write_direct(vnode_t vp, struct uio *uio, off_t oldEOF, off_t newEOF, in
        upl_t            upl;
        upl_page_info_t  *pl;
        vm_offset_t      upl_offset;
+       vm_offset_t      vector_upl_offset = 0;
        u_int32_t        io_req_size;
        u_int32_t        offset_in_file;
        u_int32_t        offset_in_iovbase;
-       u_int32_t        io_size;
-       int              io_flag;
-       int              bflag;
-       vm_size_t        upl_size;
+       u_int32_t        io_size;
+       int              io_flag = 0;
+       upl_size_t       upl_size, vector_upl_size = 0;
        vm_size_t        upl_needed_size;
        mach_msg_type_number_t  pages_in_pl;
        int              upl_flags;
@@ -1904,15 +2058,14 @@ cluster_write_direct(vnode_t vp, struct uio *uio, off_t oldEOF, off_t newEOF, in
        user_addr_t      iov_base;
        u_int32_t        mem_alignment_mask;
        u_int32_t        devblocksize;
-       u_int32_t        max_upl_size;
+       u_int32_t        max_upl_size;
 
+       u_int32_t        vector_upl_iosize = 0;
+       int              issueVectorUPL = 0,useVectorUPL = (uio->uio_iovcnt > 1);
+       off_t            v_upl_uio_offset = 0;
+       int              vector_upl_index=0;
+       upl_t            vector_upl = NULL;
 
-       max_upl_size = cluster_max_io_size(vp->v_mount, CL_WRITE);
-
-       if (flags & IO_PASSIVE)
-               bflag = CL_PASSIVE;
-       else
-               bflag = 0;
 
        /*
         * When we enter this routine, we know
@@ -1921,11 +2074,20 @@ cluster_write_direct(vnode_t vp, struct uio *uio, off_t oldEOF, off_t newEOF, in
        KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 75)) | DBG_FUNC_START,
                     (int)uio->uio_offset, *write_length, (int)newEOF, 0, 0);
 
+       max_upl_size = cluster_max_io_size(vp->v_mount, CL_WRITE);
+
+       io_flag = CL_ASYNC | CL_PRESERVE | CL_COMMIT | CL_THROTTLE | CL_DIRECT_IO;
+
+       if (flags & IO_PASSIVE)
+               io_flag |= CL_PASSIVE;
+
        iostate.io_completed = 0;
        iostate.io_issued = 0;
        iostate.io_error = 0;
        iostate.io_wanted = 0;
 
+       lck_mtx_init(&iostate.io_mtxp, cl_mtx_grp, cl_mtx_attr);
+
        mem_alignment_mask = (u_int32_t)vp->v_mount->mnt_alignmentmask;
        devblocksize = (u_int32_t)vp->v_mount->mnt_devblocksize;
 
@@ -1978,6 +2140,23 @@ next_dwrite:
                if (io_size > max_upl_size)
                        io_size = max_upl_size;
 
+               if(useVectorUPL && (iov_base & PAGE_MASK)) {
+                       /*
+                        * We have an iov_base that's not page-aligned.
+                        * Issue all I/O's that have been collected within 
+                        * this Vectored UPL.
+                        */
+                       if(vector_upl_index) {
+                               retval = vector_cluster_io(vp, vector_upl, vector_upl_offset, v_upl_uio_offset, vector_upl_iosize, io_flag, (buf_t)NULL, &iostate, callback, callback_arg);
+                               reset_vector_run_state();
+                       }
+                       
+                      /*
+                       * After this point, if we are using the Vector UPL path and the base is
+                       * not page-aligned then the UPL with that base will be the first in the vector UPL.
+                       */
+               }
+
                upl_offset = (vm_offset_t)((u_int32_t)iov_base & PAGE_MASK);
                upl_needed_size = (upl_offset + io_size + (PAGE_SIZE -1)) & ~PAGE_MASK;
 
@@ -2062,6 +2241,18 @@ next_dwrite:
                         */
                        goto wait_for_dwrites;
                }
+               
+               if(useVectorUPL) {
+                       vm_offset_t end_off = ((iov_base + io_size) & PAGE_MASK);
+                       if(end_off)
+                               issueVectorUPL = 1;
+                       /*
+                        * After this point, if we are using a vector UPL, then
+                        * either all the UPL elements end on a page boundary OR
+                        * this UPL is the last element because it does not end
+                        * on a page boundary.
+                        */
+               }
 
                /*
                 * Now look for pages already in the cache
@@ -2077,20 +2268,8 @@ next_dwrite:
                 * if there are already too many outstanding writes
                 * wait until some complete before issuing the next
                 */
-               lck_mtx_lock(cl_mtxp);
-
-               while ((iostate.io_issued - iostate.io_completed) > (2 * max_upl_size)) {
-
-                       KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 95)) | DBG_FUNC_START,
-                                       iostate.io_issued, iostate.io_completed, 2 * max_upl_size, 0, 0);
-
-                       iostate.io_wanted = 1;
-                       msleep((caddr_t)&iostate.io_wanted, cl_mtxp, PRIBIO + 1, "cluster_write_direct", NULL);
-
-                       KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 95)) | DBG_FUNC_END,
-                                       iostate.io_issued, iostate.io_completed, 2 * max_upl_size, 0, 0);
-               }       
-               lck_mtx_unlock(cl_mtxp);
+               if (iostate.io_issued > iostate.io_completed)
+                       cluster_iostate_wait(&iostate, max_upl_size * IO_SCALE(vp, 2), "cluster_write_direct");
 
                if (iostate.io_error) {
                        /*
@@ -2104,20 +2283,51 @@ next_dwrite:
 
                        goto wait_for_dwrites;
                }
-               io_flag = CL_ASYNC | CL_PRESERVE | CL_COMMIT | CL_THROTTLE | CL_DIRECT_IO | bflag;
 
                KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 77)) | DBG_FUNC_START,
                             (int)upl_offset, (int)uio->uio_offset, io_size, io_flag, 0);
 
-               retval = cluster_io(vp, upl, upl_offset, uio->uio_offset,
+               if(!useVectorUPL)
+                       retval = cluster_io(vp, upl, upl_offset, uio->uio_offset,
                                   io_size, io_flag, (buf_t)NULL, &iostate, callback, callback_arg);
 
+               else {
+                       if(!vector_upl_index) {
+                               vector_upl = vector_upl_create(upl_offset);
+                               v_upl_uio_offset = uio->uio_offset;
+                               vector_upl_offset = upl_offset;
+                       }
+
+                       vector_upl_set_subupl(vector_upl,upl,upl_size);
+                       vector_upl_set_iostate(vector_upl, upl, vector_upl_size, upl_size);
+                       vector_upl_index++;
+                       vector_upl_iosize += io_size;
+                       vector_upl_size += upl_size;
+
+                       if(issueVectorUPL || vector_upl_index ==  MAX_VECTOR_UPL_ELEMENTS || vector_upl_size >= MAX_VECTOR_UPL_SIZE) {
+                               retval = vector_cluster_io(vp, vector_upl, vector_upl_offset, v_upl_uio_offset, vector_upl_iosize, io_flag, (buf_t)NULL, &iostate, callback, callback_arg);
+                               reset_vector_run_state();
+                       }
+               }       
+
                /*
                 * update the uio structure to
                 * reflect the I/O that we just issued
                 */
                uio_update(uio, (user_size_t)io_size);
 
+               /*
+                * in case we end up calling through to cluster_write_copy to finish
+                * the tail of this request, we need to update the oldEOF so that we
+                * don't zero-fill the head of a page if we've successfully written
+                * data to that area... 'cluster_write_copy' will zero-fill the head of a
+                * page that is beyond the oldEOF if the write is unaligned... we only
+                * want that to happen for the very first page of the cluster_write, 
+                * NOT the first page of each vector making up a multi-vector write.
+                */
+               if (uio->uio_offset > oldEOF)
+                       oldEOF = uio->uio_offset;
+
                io_req_size -= io_size;
 
                KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 77)) | DBG_FUNC_END,
@@ -2139,28 +2349,24 @@ next_dwrite:
         }
 
 wait_for_dwrites:
-       if (iostate.io_issued) {
+
+       if (retval == 0 && iostate.io_error == 0 && useVectorUPL && vector_upl_index) {
+               retval = vector_cluster_io(vp, vector_upl, vector_upl_offset, v_upl_uio_offset, vector_upl_iosize, io_flag, (buf_t)NULL, &iostate, callback, callback_arg);
+               reset_vector_run_state();       
+       }
+
+       if (iostate.io_issued > iostate.io_completed) {
                /*
                 * make sure all async writes issued as part of this stream
                 * have completed before we return
                 */
-               lck_mtx_lock(cl_mtxp);
-
-               while (iostate.io_issued != iostate.io_completed) {
-                       KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 95)) | DBG_FUNC_START,
-                                       iostate.io_issued, iostate.io_completed, 0, 0, 0);
-
-                       iostate.io_wanted = 1;
-                       msleep((caddr_t)&iostate.io_wanted, cl_mtxp, PRIBIO + 1, "cluster_write_direct", NULL);
-
-                       KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 95)) | DBG_FUNC_END,
-                                       iostate.io_issued, iostate.io_completed, 0, 0, 0);
-               }       
-               lck_mtx_unlock(cl_mtxp);
+               cluster_iostate_wait(&iostate, 0, "cluster_write_direct");
        }
        if (iostate.io_error)
                retval = iostate.io_error;
 
+       lck_mtx_destroy(&iostate.io_mtxp, cl_mtx_grp);
+
        if (io_req_size && retval == 0) {
                /*
                 * we couldn't handle the tail of this request in DIRECT mode
@@ -2169,6 +2375,9 @@ wait_for_dwrites:
                 * note that flags will never have IO_HEADZEROFILL or IO_TAILZEROFILL set
                 * so we can just pass 0 in for the headOff and tailOff
                 */
+               if (uio->uio_offset > oldEOF)
+                       oldEOF = uio->uio_offset;
+
                retval = cluster_write_copy(vp, uio, io_req_size, oldEOF, newEOF, (off_t)0, (off_t)0, flags, callback, callback_arg);
 
                *write_type = IO_UNKNOWN;
@@ -2191,7 +2400,7 @@ cluster_write_contig(vnode_t vp, struct uio *uio, off_t newEOF, int *write_type,
        u_int32_t        tail_size = 0;
        u_int32_t        io_size;
        u_int32_t        xsize;
-       vm_size_t        upl_size;
+       upl_size_t       upl_size;
        vm_size_t        upl_needed_size;
        mach_msg_type_number_t  pages_in_pl;
        int              upl_flags;
@@ -2220,6 +2429,8 @@ cluster_write_contig(vnode_t vp, struct uio *uio, off_t newEOF, int *write_type,
         iostate.io_error = 0;
         iostate.io_wanted = 0;
 
+       lck_mtx_init(&iostate.io_mtxp, cl_mtx_grp, cl_mtx_attr);
+
 next_cwrite:
        io_size = *write_length;
 
@@ -2308,22 +2519,9 @@ next_cwrite:
                 * if there are already too many outstanding writes
                 * wait until some have completed before issuing the next
                 */
-               if (iostate.io_issued) {
-                       lck_mtx_lock(cl_mtxp);
+               if (iostate.io_issued > iostate.io_completed)
+                       cluster_iostate_wait(&iostate, MAX_IO_CONTIG_SIZE * IO_SCALE(vp, 2), "cluster_write_contig");
 
-                       while ((iostate.io_issued - iostate.io_completed) > (2 * MAX_IO_CONTIG_SIZE)) {
-
-                               KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 95)) | DBG_FUNC_START,
-                                               iostate.io_issued, iostate.io_completed, 2 * MAX_IO_CONTIG_SIZE, 0, 0);
-
-                               iostate.io_wanted = 1;
-                               msleep((caddr_t)&iostate.io_wanted, cl_mtxp, PRIBIO + 1, "cluster_write_contig", NULL);
-
-                               KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 95)) | DBG_FUNC_END,
-                                               iostate.io_issued, iostate.io_completed, 2 * MAX_IO_CONTIG_SIZE, 0, 0);
-                       }
-                       lck_mtx_unlock(cl_mtxp);
-               }
                 if (iostate.io_error) {
                         /*
                          * one of the earlier writes we issued ran into a hard error
@@ -2367,23 +2565,14 @@ wait_for_cwrites:
          * make sure all async writes that are part of this stream
          * have completed before we proceed
          */
-        lck_mtx_lock(cl_mtxp);
-
-        while (iostate.io_issued != iostate.io_completed) {
-               KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 95)) | DBG_FUNC_START,
-                               iostate.io_issued, iostate.io_completed, 0, 0, 0);
-
-               iostate.io_wanted = 1;
-               msleep((caddr_t)&iostate.io_wanted, cl_mtxp, PRIBIO + 1, "cluster_write_contig", NULL);
-
-               KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 95)) | DBG_FUNC_END,
-                               iostate.io_issued, iostate.io_completed, 0, 0, 0);
-        }
-        lck_mtx_unlock(cl_mtxp);
+       if (iostate.io_issued > iostate.io_completed)
+               cluster_iostate_wait(&iostate, 0, "cluster_write_contig");
 
         if (iostate.io_error)
                error = iostate.io_error;
 
+       lck_mtx_destroy(&iostate.io_mtxp, cl_mtx_grp);
+
        if (error == 0 && tail_size)
                error = cluster_align_phys_io(vp, uio, src_paddr, tail_size, 0, callback, callback_arg);
 
@@ -2398,6 +2587,42 @@ wait_for_cwrites:
 }
 
 
+/*
+ * need to avoid a race between an msync of a range of pages dirtied via mmap
+ * vs a filesystem such as HFS deciding to write a 'hole' to disk via cluster_write's
+ * zerofill mechanism before it has seen the VNOP_PAGEOUTs for the pages being msync'd
+ *
+ * we should never force-zero-fill pages that are already valid in the cache...
+ * the entire page contains valid data (either from disk, zero-filled or dirtied
+ * via an mmap) so we can only do damage by trying to zero-fill
+ *
+ */
+static int
+cluster_zero_range(upl_t upl, upl_page_info_t *pl, int flags, int io_offset, off_t zero_off, off_t upl_f_offset, int bytes_to_zero)
+{
+       int zero_pg_index;
+       boolean_t need_cluster_zero = TRUE;
+
+        if ((flags & (IO_NOZEROVALID | IO_NOZERODIRTY))) {
+
+               bytes_to_zero = min(bytes_to_zero, PAGE_SIZE - (int)(zero_off & PAGE_MASK_64));
+               zero_pg_index = (int)((zero_off - upl_f_offset) / PAGE_SIZE_64);
+
+               if (upl_valid_page(pl, zero_pg_index)) {
+                       /*
+                        * never force zero valid pages - dirty or clean
+                        * we'll leave these in the UPL for cluster_write_copy to deal with
+                        */
+                       need_cluster_zero = FALSE;
+               } 
+       }
+       if (need_cluster_zero == TRUE)
+               cluster_zero(upl, io_offset, bytes_to_zero, NULL);
+
+       return (bytes_to_zero);
+}
+
+
 static int
 cluster_write_copy(vnode_t vp, struct uio *uio, u_int32_t io_req_size, off_t oldEOF, off_t newEOF, off_t headOff,
                   off_t tailOff, int flags, int (*callback)(buf_t, void *), void *callback_arg)
@@ -2422,17 +2647,14 @@ cluster_write_copy(vnode_t vp, struct uio *uio, u_int32_t io_req_size, off_t old
        off_t            zero_off;
        long long        zero_cnt1;
        off_t            zero_off1;
+       off_t            write_off = 0;
+       int              write_cnt = 0;
+       boolean_t        first_pass = FALSE;
        struct cl_extent cl;
-        int              intersection;
        struct cl_writebehind *wbp;
        int              bflag;
-       u_int            max_cluster_pgcount;
-       u_int            max_io_size;
-
-       if (flags & IO_PASSIVE)
-               bflag = CL_PASSIVE;
-       else
-               bflag = 0;
+       u_int            max_cluster_pgcount;
+       u_int            max_io_size;
 
        if (uio) {
                KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 40)) | DBG_FUNC_START,
@@ -2445,6 +2667,11 @@ cluster_write_copy(vnode_t vp, struct uio *uio, u_int32_t io_req_size, off_t old
 
                io_resid = 0;
        }
+       if (flags & IO_PASSIVE)
+               bflag = CL_PASSIVE;
+       else
+               bflag = 0;
+
        zero_cnt  = 0;
        zero_cnt1 = 0;
        zero_off  = 0;
@@ -2470,6 +2697,16 @@ cluster_write_copy(vnode_t vp, struct uio *uio, u_int32_t io_req_size, off_t old
                        zero_cnt = newEOF - headOff;
                        zero_off = headOff;
                }
+       } else {
+               if (uio && uio->uio_offset > oldEOF) {
+                       zero_off = uio->uio_offset & ~PAGE_MASK_64;
+
+                       if (zero_off >= oldEOF) {
+                               zero_cnt = uio->uio_offset - zero_off;
+
+                               flags |= IO_HEADZEROFILL;
+                       }
+               }
        }
        if (flags & IO_TAILZEROFILL) {
                if (uio) {
@@ -2478,13 +2715,32 @@ cluster_write_copy(vnode_t vp, struct uio *uio, u_int32_t io_req_size, off_t old
                        if (zero_off1 < tailOff)
                                zero_cnt1 = tailOff - zero_off1;
                }       
+       } else {
+               if (uio && newEOF > oldEOF) {
+                       zero_off1 = uio->uio_offset + io_req_size;
+
+                       if (zero_off1 == newEOF && (zero_off1 & PAGE_MASK_64)) {
+                               zero_cnt1 = PAGE_SIZE_64 - (zero_off1 & PAGE_MASK_64);
+
+                               flags |= IO_TAILZEROFILL;
+                       }
+               }
        }
        if (zero_cnt == 0 && uio == (struct uio *) 0) {
                KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 40)) | DBG_FUNC_END,
                             retval, 0, 0, 0, 0);
                return (0);
        }
-
+       if (uio) {
+               write_off = uio->uio_offset;
+               write_cnt = uio_resid(uio);
+               /*
+                * delay updating the sequential write info
+                * in the control block until we've obtained
+                * the lock for it
+                */
+               first_pass = TRUE;
+       }
        while ((total_size = (io_resid + zero_cnt + zero_cnt1)) && retval == 0) {
                /*
                 * for this iteration of the loop, figure out where our starting point is
@@ -2513,11 +2769,11 @@ cluster_write_copy(vnode_t vp, struct uio *uio, u_int32_t io_req_size, off_t old
                         * because IO_HEADZEROFILL and IO_TAILZEROFILL not set
                         */
                        if ((start_offset + total_size) > max_io_size)
-                               total_size -= start_offset;
+                               total_size = max_io_size - start_offset;
                        xfer_resid = total_size;
 
                        retval = cluster_copy_ubc_data_internal(vp, uio, &xfer_resid, 1, 1);
-                       
+
                        if (retval)
                                break;
 
@@ -2575,14 +2831,14 @@ cluster_write_copy(vnode_t vp, struct uio *uio, u_int32_t io_req_size, off_t old
                                      upl_size,
                                      &upl,
                                      &pl,
-                                     UPL_SET_LITE | UPL_WILL_MODIFY);
+                                     UPL_SET_LITE | (( uio!=NULL && (uio->uio_flags & UIO_FLAGS_IS_COMPRESSED_FILE)) ? 0 : UPL_WILL_MODIFY));
                if (kret != KERN_SUCCESS)
                        panic("cluster_write_copy: failed to get pagelist");
 
                KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 41)) | DBG_FUNC_END,
-                       (int)upl, (int)upl_f_offset, start_offset, 0, 0);
+                       upl, (int)upl_f_offset, start_offset, 0, 0);
 
-               if (start_offset && !upl_valid_page(pl, 0)) {
+               if (start_offset && upl_f_offset < oldEOF && !upl_valid_page(pl, 0)) {
                        int   read_size;
 
                        /*
@@ -2592,8 +2848,8 @@ cluster_write_copy(vnode_t vp, struct uio *uio, u_int32_t io_req_size, off_t old
                         */
                        read_size = PAGE_SIZE;
 
-                       if ((upl_f_offset + read_size) > newEOF)
-                               read_size = newEOF - upl_f_offset;
+                       if ((upl_f_offset + read_size) > oldEOF)
+                               read_size = oldEOF - upl_f_offset;
 
                        retval = cluster_io(vp, upl, 0, upl_f_offset, read_size,
                                            CL_READ | bflag, (buf_t)NULL, (struct clios *)NULL, callback, callback_arg);
@@ -2604,13 +2860,13 @@ cluster_write_copy(vnode_t vp, struct uio *uio, u_int32_t io_req_size, off_t old
                                 * to release the rest of the pages in the upl without modifying
                                 * there state and mark the failed page in error
                                 */
-                               ubc_upl_abort_range(upl, 0, PAGE_SIZE, UPL_ABORT_DUMP_PAGES);
+                               ubc_upl_abort_range(upl, 0, PAGE_SIZE, UPL_ABORT_DUMP_PAGES|UPL_ABORT_FREE_ON_EMPTY);
 
                                if (upl_size > PAGE_SIZE)
                                        ubc_upl_abort_range(upl, 0, upl_size, UPL_ABORT_FREE_ON_EMPTY);
 
                                KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 45)) | DBG_FUNC_NONE,
-                                            (int)upl, 0, 0, retval, 0);
+                                            upl, 0, 0, retval, 0);
                                break;
                        }
                }
@@ -2628,8 +2884,8 @@ cluster_write_copy(vnode_t vp, struct uio *uio, u_int32_t io_req_size, off_t old
 
                                read_size = PAGE_SIZE;
 
-                               if ((upl_f_offset + upl_offset + read_size) > newEOF)
-                                       read_size = newEOF - (upl_f_offset + upl_offset);
+                               if ((off_t)(upl_f_offset + upl_offset + read_size) > oldEOF)
+                                       read_size = oldEOF - (upl_f_offset + upl_offset);
 
                                retval = cluster_io(vp, upl, upl_offset, upl_f_offset + upl_offset, read_size,
                                                    CL_READ | bflag, (buf_t)NULL, (struct clios *)NULL, callback, callback_arg);
@@ -2640,13 +2896,13 @@ cluster_write_copy(vnode_t vp, struct uio *uio, u_int32_t io_req_size, off_t old
                                         * need to release the rest of the pages in the upl without
                                         * modifying there state and mark the failed page in error
                                         */
-                                       ubc_upl_abort_range(upl, upl_offset, PAGE_SIZE, UPL_ABORT_DUMP_PAGES);
+                                       ubc_upl_abort_range(upl, upl_offset, PAGE_SIZE, UPL_ABORT_DUMP_PAGES|UPL_ABORT_FREE_ON_EMPTY);
 
                                        if (upl_size > PAGE_SIZE)
                                                ubc_upl_abort_range(upl, 0, upl_size, UPL_ABORT_FREE_ON_EMPTY);
 
                                        KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 45)) | DBG_FUNC_NONE,
-                                                    (int)upl, 0, 0, retval, 0);
+                                                    upl, 0, 0, retval, 0);
                                        break;
                                }
                        }
@@ -2661,22 +2917,8 @@ cluster_write_copy(vnode_t vp, struct uio *uio, u_int32_t io_req_size, off_t old
                        else
                                bytes_to_zero = xfer_resid;
 
-                       if ( !(flags & (IO_NOZEROVALID | IO_NOZERODIRTY))) {
-                               cluster_zero(upl, io_offset, bytes_to_zero, NULL);
-                       } else {
-                               int zero_pg_index;
-
-                               bytes_to_zero = min(bytes_to_zero, PAGE_SIZE - (int)(zero_off & PAGE_MASK_64));
-                               zero_pg_index = (int)((zero_off - upl_f_offset) / PAGE_SIZE_64);
-
-                               if ( !upl_valid_page(pl, zero_pg_index)) {
-                                       cluster_zero(upl, io_offset, bytes_to_zero, NULL); 
+                       bytes_to_zero = cluster_zero_range(upl, pl, flags, io_offset, zero_off, upl_f_offset, bytes_to_zero);
 
-                               } else if ((flags & (IO_NOZERODIRTY | IO_NOZEROVALID)) == IO_NOZERODIRTY &&
-                                          !upl_dirty_page(pl, zero_pg_index)) {
-                                       cluster_zero(upl, io_offset, bytes_to_zero, NULL); 
-                               }
-                       }
                        xfer_resid -= bytes_to_zero;
                        zero_cnt   -= bytes_to_zero;
                        zero_off   += bytes_to_zero;
@@ -2691,11 +2933,10 @@ cluster_write_copy(vnode_t vp, struct uio *uio, u_int32_t io_req_size, off_t old
                        retval = cluster_copy_upl_data(uio, upl, io_offset, (int *)&io_requested);
 
                        if (retval) {
-
                                ubc_upl_abort_range(upl, 0, upl_size, UPL_ABORT_DUMP_PAGES | UPL_ABORT_FREE_ON_EMPTY);
 
                                KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 45)) | DBG_FUNC_NONE,
-                                            (int)upl, 0, 0, retval, 0);
+                                            upl, 0, 0, retval, 0);
                        } else {
                                io_resid   -= bytes_to_move;
                                xfer_resid -= bytes_to_move;
@@ -2709,27 +2950,13 @@ cluster_write_copy(vnode_t vp, struct uio *uio, u_int32_t io_req_size, off_t old
                        else
                                bytes_to_zero = xfer_resid;
 
-                       if ( !(flags & (IO_NOZEROVALID | IO_NOZERODIRTY))) {
-                               cluster_zero(upl, io_offset, bytes_to_zero, NULL); 
-                       } else {
-                               int zero_pg_index;
-                       
-                               bytes_to_zero = min(bytes_to_zero, PAGE_SIZE - (int)(zero_off1 & PAGE_MASK_64));
-                               zero_pg_index = (int)((zero_off1 - upl_f_offset) / PAGE_SIZE_64);
-
-                               if ( !upl_valid_page(pl, zero_pg_index)) {
-                                       cluster_zero(upl, io_offset, bytes_to_zero, NULL); 
-                               } else if ((flags & (IO_NOZERODIRTY | IO_NOZEROVALID)) == IO_NOZERODIRTY &&
-                                          !upl_dirty_page(pl, zero_pg_index)) {
-                                       cluster_zero(upl, io_offset, bytes_to_zero, NULL); 
-                               }
-                       }
+                       bytes_to_zero = cluster_zero_range(upl, pl, flags, io_offset, zero_off1, upl_f_offset, bytes_to_zero);
+
                        xfer_resid -= bytes_to_zero;
                        zero_cnt1  -= bytes_to_zero;
                        zero_off1  += bytes_to_zero;
                        io_offset  += bytes_to_zero;
                }
-
                if (retval == 0) {
                        int cl_index;
                        int ret_cluster_try_push;
@@ -2745,43 +2972,55 @@ cluster_write_copy(vnode_t vp, struct uio *uio, u_int32_t io_req_size, off_t old
                                 */
                                cluster_zero(upl, io_size, upl_size - io_size, NULL); 
                        }
-                       if (flags & IO_SYNC)
+                       /*
+                        * release the upl now if we hold one since...
+                        * 1) pages in it may be present in the sparse cluster map
+                        *    and may span 2 separate buckets there... if they do and 
+                        *    we happen to have to flush a bucket to make room and it intersects
+                        *    this upl, a deadlock may result on page BUSY
+                        * 2) we're delaying the I/O... from this point forward we're just updating
+                        *    the cluster state... no need to hold the pages, so commit them
+                        * 3) IO_SYNC is set...
+                        *    because we had to ask for a UPL that provides currenty non-present pages, the
+                        *    UPL has been automatically set to clear the dirty flags (both software and hardware)
+                        *    upon committing it... this is not the behavior we want since it's possible for
+                        *    pages currently present as part of a mapped file to be dirtied while the I/O is in flight.
+                        *    we'll pick these pages back up later with the correct behavior specified.
+                        * 4) we don't want to hold pages busy in a UPL and then block on the cluster lock... if a flush
+                        *    of this vnode is in progress, we will deadlock if the pages being flushed intersect the pages
+                        *    we hold since the flushing context is holding the cluster lock.
+                        */
+                       ubc_upl_commit_range(upl, 0, upl_size,
+                                            UPL_COMMIT_SET_DIRTY | UPL_COMMIT_INACTIVATE | UPL_COMMIT_FREE_ON_EMPTY);
+check_cluster:
+                       /*
+                        * calculate the last logical block number 
+                        * that this delayed I/O encompassed
+                        */
+                       cl.e_addr = (daddr64_t)((upl_f_offset + (off_t)upl_size) / PAGE_SIZE_64);
+
+                       if (flags & IO_SYNC) {
                                /*
                                 * if the IO_SYNC flag is set than we need to 
                                 * bypass any clusters and immediately issue
                                 * the I/O
                                 */
                                goto issue_io;
-check_cluster:
+                       }
                        /*
                         * take the lock to protect our accesses
                         * of the writebehind and sparse cluster state
                         */
                        wbp = cluster_get_wbp(vp, CLW_ALLOCATE | CLW_RETURNLOCKED);
 
-                       /*
-                        * calculate the last logical block number 
-                        * that this delayed I/O encompassed
-                        */
-                       cl.e_addr = (daddr64_t)((upl_f_offset + (off_t)upl_size) / PAGE_SIZE_64);
-
                        if (wbp->cl_scmap) {
 
                                if ( !(flags & IO_NOCACHE)) {
                                        /*
                                         * we've fallen into the sparse
                                         * cluster method of delaying dirty pages
-                                        * first, we need to release the upl if we hold one
-                                        * since pages in it may be present in the sparse cluster map
-                                        * and may span 2 separate buckets there... if they do and 
-                                        * we happen to have to flush a bucket to make room and it intersects
-                                        * this upl, a deadlock may result on page BUSY
                                         */
-                                       if (upl_size)
-                                               ubc_upl_commit_range(upl, 0, upl_size,
-                                                                    UPL_COMMIT_SET_DIRTY | UPL_COMMIT_INACTIVATE | UPL_COMMIT_FREE_ON_EMPTY);
-
-                                       sparse_cluster_add(wbp, vp, &cl, newEOF, callback, callback_arg);
+                                       sparse_cluster_add(&(wbp->cl_scmap), vp, &cl, newEOF, callback, callback_arg);
 
                                        lck_mtx_unlock(&wbp->cl_lockw);
 
@@ -2793,21 +3032,10 @@ check_cluster:
                                 * to uncached writes on the file, so go ahead
                                 * and push whatever's in the sparse map
                                 * and switch back to normal clustering
-                                *
-                                * see the comment above concerning a possible deadlock...
                                 */
-                               if (upl_size) {
-                                       ubc_upl_commit_range(upl, 0, upl_size,
-                                                            UPL_COMMIT_SET_DIRTY | UPL_COMMIT_INACTIVATE | UPL_COMMIT_FREE_ON_EMPTY);
-                                       /*
-                                        * setting upl_size to 0 keeps us from committing a
-                                        * second time in the start_new_cluster path
-                                        */
-                                       upl_size = 0;
-                               }
-                               sparse_cluster_push(wbp, vp, newEOF, PUSH_ALL, callback, callback_arg);
-
                                wbp->cl_number = 0;
+
+                               sparse_cluster_push(&(wbp->cl_scmap), vp, newEOF, PUSH_ALL, 0, callback, callback_arg);
                                /*
                                 * no clusters of either type present at this point
                                 * so just go directly to start_new_cluster since
@@ -2816,9 +3044,17 @@ check_cluster:
                                 * to avoid the deadlock with sparse_cluster_push
                                 */
                                goto start_new_cluster;
-                       }                   
-                       upl_offset = 0;
+                       }
+                       if (first_pass) {
+                               if (write_off == wbp->cl_last_write)
+                                       wbp->cl_seq_written += write_cnt;
+                               else
+                                       wbp->cl_seq_written = write_cnt;
 
+                               wbp->cl_last_write = write_off + write_cnt;
+
+                               first_pass = FALSE;
+                       }
                        if (wbp->cl_number == 0)
                                /*
                                 * no clusters currently present
@@ -2862,21 +3098,6 @@ check_cluster:
                                                 */
                                                wbp->cl_clusters[cl_index].e_addr = wbp->cl_clusters[cl_index].b_addr + max_cluster_pgcount;
 
-                                               if (upl_size) {
-                                                       daddr64_t start_pg_in_upl;
-
-                                                       start_pg_in_upl = (daddr64_t)(upl_f_offset / PAGE_SIZE_64);
-                                                       
-                                                       if (start_pg_in_upl < wbp->cl_clusters[cl_index].e_addr) {
-                                                               intersection = (int)((wbp->cl_clusters[cl_index].e_addr - start_pg_in_upl) * PAGE_SIZE);
-
-                                                               ubc_upl_commit_range(upl, upl_offset, intersection,
-                                                                                    UPL_COMMIT_SET_DIRTY | UPL_COMMIT_INACTIVATE | UPL_COMMIT_FREE_ON_EMPTY);
-                                                               upl_f_offset += intersection;
-                                                               upl_offset   += intersection;
-                                                               upl_size     -= intersection;
-                                                       }
-                                               }
                                                cl.b_addr = wbp->cl_clusters[cl_index].e_addr;
                                        }
                                        /*
@@ -2930,21 +3151,6 @@ check_cluster:
                                                 */
                                                wbp->cl_clusters[cl_index].b_addr = wbp->cl_clusters[cl_index].e_addr - max_cluster_pgcount;
 
-                                               if (upl_size) {
-                                                       intersection = (int)((cl.e_addr - wbp->cl_clusters[cl_index].b_addr) * PAGE_SIZE);
-
-                                                       if ((u_int)intersection > upl_size)
-                                                               /*
-                                                                * because the current write may consist of a number of pages found in the cache
-                                                                * which are not part of the UPL, we may have an intersection that exceeds
-                                                                * the size of the UPL that is also part of this write
-                                                                */
-                                                               intersection = upl_size;
-
-                                                       ubc_upl_commit_range(upl, upl_offset + (upl_size - intersection), intersection,
-                                                                            UPL_COMMIT_SET_DIRTY | UPL_COMMIT_INACTIVATE | UPL_COMMIT_FREE_ON_EMPTY);
-                                                       upl_size -= intersection;
-                                               }
                                                cl.e_addr = wbp->cl_clusters[cl_index].b_addr;
                                        }
                                        /*
@@ -2963,14 +3169,27 @@ check_cluster:
                                 */
                                goto delay_io;
 
-                       if (wbp->cl_number < MAX_CLUSTERS)
+                       if (!((unsigned int)vfs_flags(vp->v_mount) & MNT_DEFWRITE) &&
+                           wbp->cl_number == MAX_CLUSTERS &&
+                           wbp->cl_seq_written >= (MAX_CLUSTERS * (max_cluster_pgcount * PAGE_SIZE))) {
+                               uint32_t        n;
+
+                               if (vp->v_mount->mnt_kern_flag & MNTK_SSD)
+                                       n = WRITE_BEHIND_SSD;
+                               else
+                                       n = WRITE_BEHIND;
+
+                               while (n--)
+                                       cluster_try_push(wbp, vp, newEOF, 0, 0, callback, callback_arg);
+                       }
+                       if (wbp->cl_number < MAX_CLUSTERS) {
                                /*
                                 * we didn't find an existing cluster to
                                 * merge into, but there's room to start
                                 * a new one
                                 */
                                goto start_new_cluster;
-
+                       }
                        /*
                         * no exisitng cluster to merge with and no
                         * room to start a new one... we'll try 
@@ -2988,7 +3207,7 @@ check_cluster:
                         */
                        if (!((unsigned int)vfs_flags(vp->v_mount) & MNT_DEFWRITE)) {
                                
-                               ret_cluster_try_push = cluster_try_push(wbp, vp, newEOF, (flags & IO_NOCACHE) ? 0 : PUSH_DELAY, callback, callback_arg);
+                               ret_cluster_try_push = cluster_try_push(wbp, vp, newEOF, (flags & IO_NOCACHE) ? 0 : PUSH_DELAY, 0, callback, callback_arg);
                        }
 
                        /*
@@ -2999,35 +3218,14 @@ check_cluster:
                                 * no more room in the normal cluster mechanism
                                 * so let's switch to the more expansive but expensive
                                 * sparse mechanism....
-                                * first, we need to release the upl if we hold one
-                                * since pages in it may be present in the sparse cluster map (after the cluster_switch)
-                                * and may span 2 separate buckets there... if they do and 
-                                * we happen to have to flush a bucket to make room and it intersects
-                                * this upl, a deadlock may result on page BUSY
                                 */
-                               if (upl_size)
-                                       ubc_upl_commit_range(upl, upl_offset, upl_size,
-                                                            UPL_COMMIT_SET_DIRTY | UPL_COMMIT_INACTIVATE | UPL_COMMIT_FREE_ON_EMPTY);
-
                                sparse_cluster_switch(wbp, vp, newEOF, callback, callback_arg);
-                               sparse_cluster_add(wbp, vp, &cl, newEOF, callback, callback_arg);
+                               sparse_cluster_add(&(wbp->cl_scmap), vp, &cl, newEOF, callback, callback_arg);
 
                                lck_mtx_unlock(&wbp->cl_lockw);
 
                                continue;
                        }
-                       /*
-                        * we pushed one cluster successfully, so we must be sequentially writing this file
-                        * otherwise, we would have failed and fallen into the sparse cluster support
-                        * so let's take the opportunity to push out additional clusters...
-                        * this will give us better I/O locality if we're in a copy loop
-                        * (i.e.  we won't jump back and forth between the read and write points
-                        */
-                       if (!((unsigned int)vfs_flags(vp->v_mount) & MNT_DEFWRITE)) {
-                               while (wbp->cl_number)
-                                       cluster_try_push(wbp, vp, newEOF, 0, callback, callback_arg);
-                       }
-
 start_new_cluster:
                        wbp->cl_clusters[wbp->cl_number].b_addr = cl.b_addr;
                        wbp->cl_clusters[wbp->cl_number].e_addr = cl.e_addr;
@@ -3042,33 +3240,19 @@ start_new_cluster:
 
                        wbp->cl_number++;
 delay_io:
-                       if (upl_size)
-                               ubc_upl_commit_range(upl, upl_offset, upl_size,
-                                                    UPL_COMMIT_SET_DIRTY | UPL_COMMIT_INACTIVATE | UPL_COMMIT_FREE_ON_EMPTY);
-
                        lck_mtx_unlock(&wbp->cl_lockw);
 
                        continue;
 issue_io:
                        /*
-                        * we don't hold the vnode lock at this point
+                        * we don't hold the lock at this point
                         *
-                        * because we had to ask for a UPL that provides currenty non-present pages, the
-                        * UPL has been automatically set to clear the dirty flags (both software and hardware)
-                        * upon committing it... this is not the behavior we want since it's possible for
-                        * pages currently present as part of a mapped file to be dirtied while the I/O is in flight.
-                        * in order to maintain some semblance of coherency with mapped writes
-                        * we need to drop the current upl and pick it back up with COPYOUT_FROM set
+                        * we've already dropped the current upl, so pick it back up with COPYOUT_FROM set
                         * so that we correctly deal with a change in state of the hardware modify bit...
                         * we do this via cluster_push_now... by passing along the IO_SYNC flag, we force
                         * cluster_push_now to wait until all the I/Os have completed... cluster_push_now is also
                         * responsible for generating the correct sized I/O(s)
                         */
-                       ubc_upl_commit_range(upl, 0, upl_size,
-                                            UPL_COMMIT_SET_DIRTY | UPL_COMMIT_INACTIVATE | UPL_COMMIT_FREE_ON_EMPTY);
-
-                       cl.e_addr = (upl_f_offset + (off_t)upl_size) / PAGE_SIZE_64;
-
                        retval = cluster_push_now(vp, &cl, newEOF, flags, callback, callback_arg);
                }
        }
@@ -3150,13 +3334,13 @@ cluster_read_ext(vnode_t vp, struct uio *uio, off_t filesize, int xflags, int (*
 
 
 static void
-cluster_read_upl_release(upl_t upl, int start_pg, int last_pg, int flags)
+cluster_read_upl_release(upl_t upl, int start_pg, int last_pg, int take_reference)
 {
        int range;
        int abort_flags = UPL_ABORT_FREE_ON_EMPTY;
 
        if ((range = last_pg - start_pg)) {
-               if ( !(flags & IO_NOCACHE))
+               if (take_reference)
                        abort_flags |= UPL_ABORT_REFERENCE;
 
                ubc_upl_abort_range(upl, start_pg * PAGE_SIZE, range * PAGE_SIZE, abort_flags);
@@ -3170,7 +3354,7 @@ cluster_read_copy(vnode_t vp, struct uio *uio, u_int32_t io_req_size, off_t file
        upl_page_info_t *pl;
        upl_t            upl;
        vm_offset_t      upl_offset;
-       u_int32_t        upl_size;
+       u_int32_t        upl_size;
        off_t            upl_f_offset;
        int              start_offset;
        int              start_pg;
@@ -3187,8 +3371,8 @@ cluster_read_copy(vnode_t vp, struct uio *uio, u_int32_t io_req_size, off_t file
        u_int32_t        xsize;
        u_int32_t        io_size;
        u_int32_t        max_rd_size;
-       u_int32_t        max_io_size;
-       u_int32_t        max_prefetch;
+       u_int32_t        max_io_size;
+       u_int32_t        max_prefetch;
        u_int            rd_ahead_enabled = 1;
        u_int            prefetch_enabled = 1;
        struct cl_readahead *   rap;
@@ -3196,51 +3380,63 @@ cluster_read_copy(vnode_t vp, struct uio *uio, u_int32_t io_req_size, off_t file
        struct cl_extent        extent;
        int              bflag;
        int              take_reference = 1;
+#if CONFIG_EMBEDDED
        struct uthread  *ut;
+#endif /* CONFIG_EMBEDDED */
        int              policy = IOPOL_DEFAULT;
+       boolean_t        iolock_inited = FALSE;
 
+       KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 32)) | DBG_FUNC_START,
+                    (int)uio->uio_offset, io_req_size, (int)filesize, flags, 0);
+                        
+#if !CONFIG_EMBEDDED
+       policy = proc_get_task_selfdiskacc();
+#else /* !CONFIG_EMBEDDED */
        policy = current_proc()->p_iopol_disk;
 
        ut = get_bsdthread_info(current_thread());
 
        if (ut->uu_iopol_disk != IOPOL_DEFAULT)
                policy = ut->uu_iopol_disk;
+#endif /* !CONFIG_EMBEDDED */
 
-       if (policy == IOPOL_THROTTLE)
+       if (policy == IOPOL_THROTTLE || (flags & IO_NOCACHE))
                take_reference = 0;
 
        if (flags & IO_PASSIVE)
                bflag = CL_PASSIVE;
        else
-               bflag = 0;
+               bflag = 0;
 
-       max_prefetch = MAX_PREFETCH(vp);
-       max_rd_size = max_prefetch;
-       max_io_size = cluster_max_io_size(vp->v_mount, CL_READ);
+       max_io_size = cluster_max_io_size(vp->v_mount, CL_READ);
+       max_prefetch = MAX_PREFETCH(vp, max_io_size, (vp->v_mount->mnt_kern_flag & MNTK_SSD));
+       max_rd_size = max_prefetch;
 
-       KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 32)) | DBG_FUNC_START,
-                    (int)uio->uio_offset, io_req_size, (int)filesize, flags, 0);
-                        
        last_request_offset = uio->uio_offset + io_req_size;
 
+       if (last_request_offset > filesize)
+               last_request_offset = filesize;
+
        if ((flags & (IO_RAOFF|IO_NOCACHE)) || ((last_request_offset & ~PAGE_MASK_64) == (uio->uio_offset & ~PAGE_MASK_64))) {
                rd_ahead_enabled = 0;
                rap = NULL;
        } else {
-               if (cluster_hard_throttle_on(vp)) {
+               if (cluster_hard_throttle_on(vp, 1)) {
                        rd_ahead_enabled = 0;
                        prefetch_enabled = 0;
 
                        max_rd_size = HARD_THROTTLE_MAXSIZE;
+               } else if (policy == IOPOL_THROTTLE) {
+                       rd_ahead_enabled = 0;
+                       prefetch_enabled = 0;
                }
                if ((rap = cluster_get_rap(vp)) == NULL)
                        rd_ahead_enabled = 0;
+               else {
+                       extent.b_addr = uio->uio_offset / PAGE_SIZE_64;
+                       extent.e_addr = (last_request_offset - 1) / PAGE_SIZE_64;
+               }
        }
-       if (last_request_offset > filesize)
-               last_request_offset = filesize;
-       extent.b_addr = uio->uio_offset / PAGE_SIZE_64;
-        extent.e_addr = (last_request_offset - 1) / PAGE_SIZE_64;
-
        if (rap != NULL && rap->cl_ralen && (rap->cl_lastr == extent.b_addr || (rap->cl_lastr + 1) == extent.b_addr)) {
                /*
                 * determine if we already have a read-ahead in the pipe courtesy of the
@@ -3259,17 +3455,8 @@ cluster_read_copy(vnode_t vp, struct uio *uio, u_int32_t io_req_size, off_t file
                last_ioread_offset = (off_t)0;
 
        while (io_req_size && uio->uio_offset < filesize && retval == 0) {
-               /*
-                * compute the size of the upl needed to encompass
-                * the requested read... limit each call to cluster_io
-                * to the maximum UPL size... cluster_io will clip if
-                * this exceeds the maximum io_size for the device,
-                * make sure to account for 
-                * a starting offset that's not page aligned
-                */
-               start_offset = (int)(uio->uio_offset & PAGE_MASK_64);
-               upl_f_offset = uio->uio_offset - (off_t)start_offset;
-               max_size     = filesize - uio->uio_offset;
+
+               max_size = filesize - uio->uio_offset;
 
                if ((off_t)(io_req_size) < max_size)
                        io_size = io_req_size;
@@ -3336,7 +3523,7 @@ cluster_read_copy(vnode_t vp, struct uio *uio, u_int32_t io_req_size, off_t file
                                         */
                                        break;
                                
-                               if ((io_size == 0 || last_ioread_offset == last_request_offset) && rd_ahead_enabled) {
+                               if (rd_ahead_enabled && (io_size == 0 || last_ioread_offset == last_request_offset)) {
                                        /*
                                         * we're already finished the I/O for this read request
                                         * let's see if we should do a read-ahead
@@ -3354,10 +3541,23 @@ cluster_read_copy(vnode_t vp, struct uio *uio, u_int32_t io_req_size, off_t file
                                }
                                break;
                        }
-                       start_offset = (int)(uio->uio_offset & PAGE_MASK_64);
-                       upl_f_offset = uio->uio_offset - (off_t)start_offset;
-                       max_size     = filesize - uio->uio_offset;
+                       /*
+                        * recompute max_size since cluster_copy_ubc_data_internal
+                        * may have advanced uio->uio_offset
+                        */
+                       max_size = filesize - uio->uio_offset;
                }
+               /*
+                * compute the size of the upl needed to encompass
+                * the requested read... limit each call to cluster_io
+                * to the maximum UPL size... cluster_io will clip if
+                * this exceeds the maximum io_size for the device,
+                * make sure to account for 
+                * a starting offset that's not page aligned
+                */
+               start_offset = (int)(uio->uio_offset & PAGE_MASK_64);
+               upl_f_offset = uio->uio_offset - (off_t)start_offset;
+
                if (io_size > max_rd_size)
                        io_size = max_rd_size;
 
@@ -3373,7 +3573,7 @@ cluster_read_copy(vnode_t vp, struct uio *uio, u_int32_t io_req_size, off_t file
                pages_in_upl = upl_size / PAGE_SIZE;
 
                KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 33)) | DBG_FUNC_START,
-                            (int)upl, (int)upl_f_offset, upl_size, start_offset, 0);
+                            upl, (int)upl_f_offset, upl_size, start_offset, 0);
 
                kret = ubc_create_upl(vp, 
                                      upl_f_offset,
@@ -3385,7 +3585,7 @@ cluster_read_copy(vnode_t vp, struct uio *uio, u_int32_t io_req_size, off_t file
                        panic("cluster_read_copy: failed to get pagelist");
 
                KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 33)) | DBG_FUNC_END,
-                            (int)upl, (int)upl_f_offset, upl_size, start_offset, 0);
+                            upl, (int)upl_f_offset, upl_size, start_offset, 0);
 
                /*
                 * scan from the beginning of the upl looking for the first
@@ -3420,10 +3620,15 @@ cluster_read_copy(vnode_t vp, struct uio *uio, u_int32_t io_req_size, off_t file
                         * we may have to clip the size of it to keep from reading past
                         * the end of the last physical block associated with the file
                         */
+                       if (iolock_inited == FALSE) {
+                               lck_mtx_init(&iostate.io_mtxp, cl_mtx_grp, cl_mtx_attr);
+
+                               iolock_inited = TRUE;
+                       }
                        upl_offset = start_pg * PAGE_SIZE;
                        io_size    = (last_pg - start_pg) * PAGE_SIZE;
 
-                       if ((upl_f_offset + upl_offset + io_size) > filesize)
+                       if ((off_t)(upl_f_offset + upl_offset + io_size) > filesize)
                                io_size = filesize - (upl_f_offset + upl_offset);
 
                        /*
@@ -3432,6 +3637,18 @@ cluster_read_copy(vnode_t vp, struct uio *uio, u_int32_t io_req_size, off_t file
 
                        error = cluster_io(vp, upl, upl_offset, upl_f_offset + upl_offset,
                                           io_size, CL_READ | CL_ASYNC | bflag, (buf_t)NULL, &iostate, callback, callback_arg);
+
+                       if (rap) {
+                                if (extent.e_addr < rap->cl_maxra) {
+                                       /*
+                                        * we've just issued a read for a block that should have been
+                                        * in the cache courtesy of the read-ahead engine... something
+                                        * has gone wrong with the pipeline, so reset the read-ahead
+                                        * logic which will cause us to restart from scratch
+                                        */
+                                        rap->cl_maxra = 0;
+                               }
+                        }
                }
                if (error == 0) {
                        /*
@@ -3510,19 +3727,8 @@ cluster_read_copy(vnode_t vp, struct uio *uio, u_int32_t io_req_size, off_t file
                                        rap->cl_lastr = extent.e_addr;
                                }
                        }
-                       lck_mtx_lock(cl_mtxp);
-
-                       while (iostate.io_issued != iostate.io_completed) {
-                               KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 95)) | DBG_FUNC_START,
-                                               iostate.io_issued, iostate.io_completed, 0, 0, 0);
-
-                               iostate.io_wanted = 1;
-                               msleep((caddr_t)&iostate.io_wanted, cl_mtxp, PRIBIO + 1, "cluster_read_copy", NULL);
-
-                               KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 95)) | DBG_FUNC_END,
-                                               iostate.io_issued, iostate.io_completed, 0, 0, 0);
-                       }       
-                       lck_mtx_unlock(cl_mtxp);
+                       if (iostate.io_issued > iostate.io_completed)
+                               cluster_iostate_wait(&iostate, 0, "cluster_read_copy");
 
                        if (iostate.io_error)
                                error = iostate.io_error;
@@ -3535,6 +3741,9 @@ cluster_read_copy(vnode_t vp, struct uio *uio, u_int32_t io_req_size, off_t file
                                
                                io_req_size -= (val_size - io_requested);
                        }
+               } else {
+                       if (iostate.io_issued > iostate.io_completed)
+                               cluster_iostate_wait(&iostate, 0, "cluster_read_copy");
                }
                if (start_pg < last_pg) {
                        /*
@@ -3545,16 +3754,22 @@ cluster_read_copy(vnode_t vp, struct uio *uio, u_int32_t io_req_size, off_t file
                         */
                        io_size = (last_pg - start_pg) * PAGE_SIZE;
 
-                       KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 35)) | DBG_FUNC_START, (int)upl, start_pg * PAGE_SIZE, io_size, error, 0);
+                       KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 35)) | DBG_FUNC_START, upl, start_pg * PAGE_SIZE, io_size, error, 0);
 
                        if (error || (flags & IO_NOCACHE))
                                ubc_upl_abort_range(upl, start_pg * PAGE_SIZE, io_size,
                                                    UPL_ABORT_DUMP_PAGES | UPL_ABORT_FREE_ON_EMPTY);
-                       else
-                               ubc_upl_commit_range(upl, start_pg * PAGE_SIZE, io_size, 
-                                                    UPL_COMMIT_CLEAR_DIRTY | UPL_COMMIT_FREE_ON_EMPTY | UPL_COMMIT_INACTIVATE);
+                       else {
+                               int     commit_flags = UPL_COMMIT_CLEAR_DIRTY | UPL_COMMIT_FREE_ON_EMPTY;
 
-                       KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 35)) | DBG_FUNC_END, (int)upl, start_pg * PAGE_SIZE, io_size, error, 0);
+                               if (take_reference)
+                                       commit_flags |= UPL_COMMIT_INACTIVATE;
+                               else
+                                       commit_flags |= UPL_COMMIT_SPECULATE;
+
+                               ubc_upl_commit_range(upl, start_pg * PAGE_SIZE, io_size, commit_flags);
+                       }
+                       KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 35)) | DBG_FUNC_END, upl, start_pg * PAGE_SIZE, io_size, error, 0);
                }
                if ((last_pg - start_pg) < pages_in_upl) {
                        /*
@@ -3567,28 +3782,28 @@ cluster_read_copy(vnode_t vp, struct uio *uio, u_int32_t io_req_size, off_t file
                        else {
 
                                KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 35)) | DBG_FUNC_START,
-                                            (int)upl, -1, pages_in_upl - (last_pg - start_pg), 0, 0);
+                                            upl, -1, pages_in_upl - (last_pg - start_pg), 0, 0);
 
                                /*
                                 * handle any valid pages at the beginning of
                                 * the upl... release these appropriately
                                 */
-                               cluster_read_upl_release(upl, 0, start_pg, flags);
+                               cluster_read_upl_release(upl, 0, start_pg, take_reference);
 
                                /*
                                 * handle any valid pages immediately after the
                                 * pages we issued I/O for... ... release these appropriately
                                 */
-                               cluster_read_upl_release(upl, last_pg, uio_last, flags);
+                               cluster_read_upl_release(upl, last_pg, uio_last, take_reference);
 
-                               KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 35)) | DBG_FUNC_END, (int)upl, -1, -1, 0, 0);
+                               KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 35)) | DBG_FUNC_END, upl, -1, -1, 0, 0);
                        }
                }
                if (retval == 0)
                        retval = error;
 
                if (io_req_size) {
-                       if (cluster_hard_throttle_on(vp)) {
+                       if (cluster_hard_throttle_on(vp, 1)) {
                                rd_ahead_enabled = 0;
                                prefetch_enabled = 0;
 
@@ -3598,16 +3813,31 @@ cluster_read_copy(vnode_t vp, struct uio *uio, u_int32_t io_req_size, off_t file
                                        /*
                                         * coming out of throttled state
                                         */
-                                       if (rap != NULL)
-                                               rd_ahead_enabled = 1;
-                                       prefetch_enabled = 1;
-
+                                       if (policy != IOPOL_THROTTLE) {
+                                               if (rap != NULL)
+                                                       rd_ahead_enabled = 1;
+                                               prefetch_enabled = 1;
+                                       }
                                        max_rd_size = max_prefetch;
                                        last_ioread_offset = 0;
                                }
                        }
                }
        }
+       if (iolock_inited == TRUE) {
+               if (iostate.io_issued > iostate.io_completed) {
+                       /*
+                        * cluster_io returned an error after it
+                        * had already issued some I/O.  we need
+                        * to wait for that I/O to complete before
+                        * we can destroy the iostate mutex...
+                        * 'retval' already contains the early error
+                        * so no need to pick it up from iostate.io_error
+                        */
+                       cluster_iostate_wait(&iostate, 0, "cluster_read_copy");
+               }
+               lck_mtx_destroy(&iostate.io_mtxp, cl_mtx_grp);
+       }
        if (rap != NULL) {
                KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 32)) | DBG_FUNC_END,
                             (int)uio->uio_offset, io_req_size, rap->cl_lastr, retval, 0);
@@ -3629,18 +3859,16 @@ cluster_read_direct(vnode_t vp, struct uio *uio, off_t filesize, int *read_type,
        upl_t            upl;
        upl_page_info_t  *pl;
         off_t           max_io_size;
-       vm_offset_t      upl_offset;
-       vm_size_t        upl_size;
+       vm_offset_t      upl_offset, vector_upl_offset = 0;
+       upl_size_t       upl_size, vector_upl_size = 0;
        vm_size_t        upl_needed_size;
        unsigned int     pages_in_pl;
        int              upl_flags;
-       int              bflag;
        kern_return_t    kret;
        unsigned int     i;
        int              force_data_sync;
        int              retval = 0;
        int              no_zero_fill = 0;
-       int              abort_flag = 0;
        int              io_flag = 0;
        int              misaligned = 0;
        struct clios     iostate;
@@ -3653,30 +3881,37 @@ cluster_read_direct(vnode_t vp, struct uio *uio, off_t filesize, int *read_type,
         u_int32_t       xsize;
        u_int32_t        devblocksize;
        u_int32_t        mem_alignment_mask;
-       u_int32_t        max_upl_size;
-       u_int32_t        max_rd_size;
-       u_int32_t        max_rd_ahead;
+       u_int32_t        max_upl_size;
+       u_int32_t        max_rd_size;
+       u_int32_t        max_rd_ahead;
+       boolean_t        strict_uncached_IO = FALSE;
 
-       max_upl_size = cluster_max_io_size(vp->v_mount, CL_READ);
+       u_int32_t        vector_upl_iosize = 0;
+       int              issueVectorUPL = 0,useVectorUPL = (uio->uio_iovcnt > 1);
+       off_t            v_upl_uio_offset = 0;
+       int              vector_upl_index=0;
+       upl_t            vector_upl = NULL;
 
-       max_rd_size = max_upl_size;
-       max_rd_ahead = max_rd_size * 2;
+       KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 70)) | DBG_FUNC_START,
+                    (int)uio->uio_offset, (int)filesize, *read_type, *read_length, 0);
 
+       max_upl_size = cluster_max_io_size(vp->v_mount, CL_READ);
 
-       if (flags & IO_PASSIVE)
-               bflag = CL_PASSIVE;
-       else
-               bflag = 0;
+       max_rd_size = max_upl_size;
+       max_rd_ahead = max_rd_size * IO_SCALE(vp, 2);
 
-       KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 70)) | DBG_FUNC_START,
-                    (int)uio->uio_offset, (int)filesize, *read_type, *read_length, 0);
+       io_flag = CL_COMMIT | CL_READ | CL_ASYNC | CL_NOZERO | CL_DIRECT_IO;
+
+       if (flags & IO_PASSIVE)
+               io_flag |= CL_PASSIVE;
 
        iostate.io_completed = 0;
        iostate.io_issued = 0;
        iostate.io_error = 0;
        iostate.io_wanted = 0;
 
+       lck_mtx_init(&iostate.io_mtxp, cl_mtx_grp, cl_mtx_attr);
+
        devblocksize = (u_int32_t)vp->v_mount->mnt_devblocksize;
        mem_alignment_mask = (u_int32_t)vp->v_mount->mnt_alignmentmask;
 
@@ -3696,6 +3931,9 @@ cluster_read_direct(vnode_t vp, struct uio *uio, off_t filesize, int *read_type,
                 */
                devblocksize = PAGE_SIZE;
        }
+
+       strict_uncached_IO = ubc_strict_uncached_IO(vp);
+
 next_dread:
        io_req_size = *read_length;
        iov_base = uio_curriovbase(uio);
@@ -3731,12 +3969,12 @@ next_dread:
        while (io_req_size && retval == 0) {
                u_int32_t io_start;
 
-               if (cluster_hard_throttle_on(vp)) {
+               if (cluster_hard_throttle_on(vp, 1)) {
                        max_rd_size  = HARD_THROTTLE_MAXSIZE;
                        max_rd_ahead = HARD_THROTTLE_MAXSIZE - 1;
                } else {
                        max_rd_size  = max_upl_size;
-                       max_rd_ahead = max_rd_size * 2;
+                       max_rd_ahead = max_rd_size * IO_SCALE(vp, 2);
                }
                io_start = io_size = io_req_size;
 
@@ -3747,8 +3985,9 @@ next_dread:
                 * cluster_copy_ubc_data returns the resid
                 * in io_size
                 */
-               retval = cluster_copy_ubc_data_internal(vp, uio, (int *)&io_size, 0, 0);
-                       
+               if (strict_uncached_IO == FALSE) {
+                       retval = cluster_copy_ubc_data_internal(vp, uio, (int *)&io_size, 0, 0);
+               }
                /*
                 * calculate the number of bytes actually copied
                 * starting size - residual
@@ -3757,6 +3996,27 @@ next_dread:
 
                io_req_size -= xsize;
 
+               if(useVectorUPL && (xsize || (iov_base & PAGE_MASK))) {
+                       /*
+                        * We found something in the cache or we have an iov_base that's not
+                        * page-aligned.
+                        * 
+                        * Issue all I/O's that have been collected within this Vectored UPL.
+                        */
+                       if(vector_upl_index) {
+                               retval = vector_cluster_io(vp, vector_upl, vector_upl_offset, v_upl_uio_offset, vector_upl_iosize, io_flag, (buf_t)NULL, &iostate, callback, callback_arg);
+                               reset_vector_run_state();
+                       }
+                       
+                       if(xsize)
+                               useVectorUPL = 0;
+
+                      /*
+                       * After this point, if we are using the Vector UPL path and the base is
+                       * not page-aligned then the UPL with that base will be the first in the vector UPL.
+                       */
+               }
+
                /*
                 * check to see if we are finished with this request...
                 */
@@ -3804,21 +4064,26 @@ next_dread:
                         */
                        goto wait_for_dreads;
                }
-               if ((xsize = io_size) > max_rd_size)
-                       xsize = max_rd_size;
 
-               io_size = 0;
+               if (strict_uncached_IO == FALSE) {
 
-               ubc_range_op(vp, uio->uio_offset, uio->uio_offset + xsize, UPL_ROP_ABSENT, (int *)&io_size);
+                       if ((xsize = io_size) > max_rd_size)
+                               xsize = max_rd_size;
 
-               if (io_size == 0) {
-                       /*
-                        * a page must have just come into the cache
-                        * since the first page in this range is no
-                        * longer absent, go back and re-evaluate
-                        */
-                       continue;
+                       io_size = 0;
+
+                       ubc_range_op(vp, uio->uio_offset, uio->uio_offset + xsize, UPL_ROP_ABSENT, (int *)&io_size);
+
+                       if (io_size == 0) {
+                               /*
+                                * a page must have just come into the cache
+                                * since the first page in this range is no
+                                * longer absent, go back and re-evaluate
+                                */
+                               continue;
+                       }
                }
+
                iov_base = uio_curriovbase(uio);
 
                upl_offset = (vm_offset_t)((u_int32_t)iov_base & PAGE_MASK);
@@ -3827,13 +4092,11 @@ next_dread:
                KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 72)) | DBG_FUNC_START,
                             (int)upl_offset, upl_needed_size, (int)iov_base, io_size, 0);
 
-               if (upl_offset == 0 && ((io_size & PAGE_MASK) == 0)) {
+               if (upl_offset == 0 && ((io_size & PAGE_MASK) == 0))
                        no_zero_fill = 1;
-                       abort_flag = UPL_ABORT_DUMP_PAGES | UPL_ABORT_FREE_ON_EMPTY;
-               } else {
+               else
                        no_zero_fill = 0;
-                       abort_flag = UPL_ABORT_FREE_ON_EMPTY;
-               }
+
                for (force_data_sync = 0; force_data_sync < 3; force_data_sync++) {
                        pages_in_pl = 0;
                        upl_size = upl_needed_size;
@@ -3864,13 +4127,13 @@ next_dread:
                        pl = UPL_GET_INTERNAL_PAGE_LIST(upl);
 
                        for (i = 0; i < pages_in_pl; i++) {
-                               if (!upl_valid_page(pl, i))
+                               if (!upl_page_present(pl, i))
                                        break;            
                        }
                        if (i == pages_in_pl)
                                break;
 
-                       ubc_upl_abort(upl, abort_flag);
+                       ubc_upl_abort(upl, 0);
                }
                if (force_data_sync >= 3) {
                        KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 72)) | DBG_FUNC_END,
@@ -3888,32 +4151,33 @@ next_dread:
                                io_size = 0;
                }
                if (io_size == 0) {
-                       ubc_upl_abort(upl, abort_flag);
+                       ubc_upl_abort(upl, 0);
                        goto wait_for_dreads;
                }
                KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 72)) | DBG_FUNC_END,
                             (int)upl_offset, upl_size, io_size, kret, 0);
 
+               if(useVectorUPL) {
+                       vm_offset_t end_off = ((iov_base + io_size) & PAGE_MASK);
+                       if(end_off) 
+                               issueVectorUPL = 1;
+                       /*
+                        * After this point, if we are using a vector UPL, then
+                        * either all the UPL elements end on a page boundary OR
+                        * this UPL is the last element because it does not end
+                        * on a page boundary.
+                        */
+               }
+
                /*
                 * request asynchronously so that we can overlap
                 * the preparation of the next I/O
                 * if there are already too many outstanding reads
                 * wait until some have completed before issuing the next read
                 */
-               lck_mtx_lock(cl_mtxp);
-
-               while ((iostate.io_issued - iostate.io_completed) > max_rd_ahead) {
-                       KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 95)) | DBG_FUNC_START,
-                                       iostate.io_issued, iostate.io_completed, max_rd_ahead, 0, 0);
+               if (iostate.io_issued > iostate.io_completed)
+                       cluster_iostate_wait(&iostate, max_rd_ahead, "cluster_read_direct");
 
-                       iostate.io_wanted = 1;
-                       msleep((caddr_t)&iostate.io_wanted, cl_mtxp, PRIBIO + 1, "cluster_read_direct", NULL);
-
-                       KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 95)) | DBG_FUNC_END,
-                                       iostate.io_issued, iostate.io_completed, max_rd_ahead, 0, 0);
-               }       
-               lck_mtx_unlock(cl_mtxp);
-                       
                if (iostate.io_error) {
                        /*
                         * one of the earlier reads we issued ran into a hard error
@@ -3922,20 +4186,41 @@ next_dread:
                         * go wait for any other reads to complete before
                         * returning the error to the caller
                         */
-                       ubc_upl_abort(upl, abort_flag);
+                       ubc_upl_abort(upl, 0);
 
                        goto wait_for_dreads;
                }
                KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 73)) | DBG_FUNC_START,
-                            (int)upl, (int)upl_offset, (int)uio->uio_offset, io_size, 0);
+                            upl, (int)upl_offset, (int)uio->uio_offset, io_size, 0);
 
-               if (no_zero_fill)
-                       io_flag = CL_COMMIT | CL_READ | CL_ASYNC | CL_NOZERO | CL_DIRECT_IO | bflag;
-               else
-                       io_flag = CL_COMMIT | CL_READ | CL_ASYNC | CL_NOZERO | CL_DIRECT_IO | CL_PRESERVE | bflag;
 
-               retval = cluster_io(vp, upl, upl_offset, uio->uio_offset, io_size, io_flag, (buf_t)NULL, &iostate, callback, callback_arg);
+               if(!useVectorUPL) {
+                       if (no_zero_fill)
+                               io_flag &= ~CL_PRESERVE;
+                       else
+                               io_flag |= CL_PRESERVE;
+               
+                       retval = cluster_io(vp, upl, upl_offset, uio->uio_offset, io_size, io_flag, (buf_t)NULL, &iostate, callback, callback_arg);
+
+               } else {
+
+                       if(!vector_upl_index) {
+                               vector_upl = vector_upl_create(upl_offset);
+                               v_upl_uio_offset = uio->uio_offset;
+                               vector_upl_offset = upl_offset;
+                       }
 
+                       vector_upl_set_subupl(vector_upl,upl, upl_size);
+                       vector_upl_set_iostate(vector_upl, upl, vector_upl_size, upl_size);
+                       vector_upl_index++;
+                       vector_upl_size += upl_size;
+                       vector_upl_iosize += io_size;
+                       
+                       if(issueVectorUPL || vector_upl_index ==  MAX_VECTOR_UPL_ELEMENTS || vector_upl_size >= MAX_VECTOR_UPL_SIZE) {
+                               retval = vector_cluster_io(vp, vector_upl, vector_upl_offset, v_upl_uio_offset, vector_upl_iosize,  io_flag, (buf_t)NULL, &iostate, callback, callback_arg);
+                               reset_vector_run_state();       
+                       }
+               }       
                /*
                 * update the uio structure
                 */
@@ -3944,7 +4229,7 @@ next_dread:
                io_req_size -= io_size;
 
                KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 73)) | DBG_FUNC_END,
-                            (int)upl, (int)uio->uio_offset, io_req_size, retval, 0);
+                            upl, (int)uio->uio_offset, io_req_size, retval, 0);
 
        } /* end while */
 
@@ -3962,29 +4247,23 @@ next_dread:
        }
 
 wait_for_dreads:
-       if (iostate.io_issued) {
-               /*
-                * make sure all async reads that are part of this stream
-                * have completed before we return
-                */
-               lck_mtx_lock(cl_mtxp);
-
-               while (iostate.io_issued != iostate.io_completed) {
-                       KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 95)) | DBG_FUNC_START,
-                                       iostate.io_issued, iostate.io_completed, 0, 0, 0);
 
-                       iostate.io_wanted = 1;
-                       msleep((caddr_t)&iostate.io_wanted, cl_mtxp, PRIBIO + 1, "cluster_read_direct", NULL);
-
-                       KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 95)) | DBG_FUNC_END,
-                                       iostate.io_issued, iostate.io_completed, 0, 0, 0);
-               }       
-               lck_mtx_unlock(cl_mtxp);
+       if(retval == 0 && iostate.io_error == 0 && useVectorUPL && vector_upl_index) {
+               retval = vector_cluster_io(vp, vector_upl, vector_upl_offset, v_upl_uio_offset, vector_upl_iosize,  io_flag, (buf_t)NULL, &iostate, callback, callback_arg);
+               reset_vector_run_state();
        }
+       /*
+        * make sure all async reads that are part of this stream
+        * have completed before we return
+        */
+       if (iostate.io_issued > iostate.io_completed)
+               cluster_iostate_wait(&iostate, 0, "cluster_read_direct");
 
        if (iostate.io_error)
                retval = iostate.io_error;
 
+       lck_mtx_destroy(&iostate.io_mtxp, cl_mtx_grp);
+
        if (io_req_size && retval == 0) {
                /*
                 * we couldn't handle the tail of this request in DIRECT mode
@@ -4011,7 +4290,7 @@ cluster_read_contig(vnode_t vp, struct uio *uio, off_t filesize, int *read_type,
        addr64_t         dst_paddr = 0;
        user_addr_t      iov_base;
        off_t            max_size;
-       vm_size_t        upl_size;
+       upl_size_t       upl_size;
        vm_size_t        upl_needed_size;
        mach_msg_type_number_t  pages_in_pl;
        int              upl_flags;
@@ -4029,9 +4308,9 @@ cluster_read_contig(vnode_t vp, struct uio *uio, off_t filesize, int *read_type,
        int              bflag;
 
        if (flags & IO_PASSIVE)
-               bflag = CL_PASSIVE;
+               bflag = CL_PASSIVE;
        else
-               bflag = 0;
+               bflag = 0;
 
        /*
         * When we enter this routine, we know
@@ -4048,6 +4327,8 @@ cluster_read_contig(vnode_t vp, struct uio *uio, off_t filesize, int *read_type,
        iostate.io_error = 0;
        iostate.io_wanted = 0;
 
+       lck_mtx_init(&iostate.io_mtxp, cl_mtx_grp, cl_mtx_attr);
+
 next_cread:
        io_size = *read_length;
 
@@ -4145,21 +4426,9 @@ next_cread:
                 * if there are already too many outstanding reads
                 * wait until some have completed before issuing the next
                 */
-               if (iostate.io_issued) {
-                       lck_mtx_lock(cl_mtxp);
+               if (iostate.io_issued > iostate.io_completed)
+                       cluster_iostate_wait(&iostate, MAX_IO_CONTIG_SIZE * IO_SCALE(vp, 2), "cluster_read_contig");
 
-                       while ((iostate.io_issued - iostate.io_completed) > (2 * MAX_IO_CONTIG_SIZE)) {
-                               KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 95)) | DBG_FUNC_START,
-                                               iostate.io_issued, iostate.io_completed, 2 * MAX_IO_CONTIG_SIZE, 0, 0);
-
-                               iostate.io_wanted = 1;
-                               msleep((caddr_t)&iostate.io_wanted, cl_mtxp, PRIBIO + 1, "cluster_read_contig", NULL);
-
-                               KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 95)) | DBG_FUNC_END,
-                                               iostate.io_issued, iostate.io_completed, 2 * MAX_IO_CONTIG_SIZE, 0, 0);
-                       }       
-                       lck_mtx_unlock(cl_mtxp);
-               }
                if (iostate.io_error) {
                        /*
                         * one of the earlier reads we issued ran into a hard error
@@ -4200,23 +4469,14 @@ wait_for_creads:
         * make sure all async reads that are part of this stream
         * have completed before we proceed
         */
-       lck_mtx_lock(cl_mtxp);
-
-       while (iostate.io_issued != iostate.io_completed) {
-               KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 95)) | DBG_FUNC_START,
-                               iostate.io_issued, iostate.io_completed, 0, 0, 0);
-
-               iostate.io_wanted = 1;
-               msleep((caddr_t)&iostate.io_wanted, cl_mtxp, PRIBIO + 1, "cluster_read_contig", NULL);
-
-               KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 95)) | DBG_FUNC_END,
-                               iostate.io_issued, iostate.io_completed, 0, 0, 0);
-       }       
-       lck_mtx_unlock(cl_mtxp);
+       if (iostate.io_issued > iostate.io_completed)
+               cluster_iostate_wait(&iostate, 0, "cluster_read_contig");
 
        if (iostate.io_error)
                error = iostate.io_error;
 
+       lck_mtx_destroy(&iostate.io_mtxp, cl_mtx_grp);
+
        if (error == 0 && tail_size)
                error = cluster_align_phys_io(vp, uio, dst_paddr, tail_size, CL_READ, callback, callback_arg);
 
@@ -4237,7 +4497,7 @@ cluster_io_type(struct uio *uio, int *io_type, u_int32_t *io_length, u_int32_t m
         user_size_t     iov_len;
        user_addr_t      iov_base = 0;
        upl_t            upl;
-       vm_size_t        upl_size;
+       upl_size_t       upl_size;
        int              upl_flags;
        int              retval = 0;
 
@@ -4248,7 +4508,7 @@ cluster_io_type(struct uio *uio, int *io_type, u_int32_t *io_length, u_int32_t m
 
        iov_len = uio_curriovlen(uio);
 
-       KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 94)) | DBG_FUNC_START, (int)uio, (int)iov_len, 0, 0, 0);
+       KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 94)) | DBG_FUNC_START, uio, (int)iov_len, 0, 0, 0);
 
        if (iov_len) {
                iov_base = uio_curriovbase(uio);
@@ -4290,7 +4550,7 @@ cluster_io_type(struct uio *uio, int *io_type, u_int32_t *io_length, u_int32_t m
                *io_length = 0;
                *io_type   = IO_UNKNOWN;
        }
-       KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 94)) | DBG_FUNC_END, (int)iov_base, *io_type, *io_length, retval, 0);
+       KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 94)) | DBG_FUNC_END, iov_base, *io_type, *io_length, retval, 0);
 
        return (retval);
 }
@@ -4312,7 +4572,7 @@ advisory_read_ext(vnode_t vp, off_t filesize, off_t f_offset, int resid, int (*c
        upl_page_info_t *pl;
        upl_t            upl;
        vm_offset_t      upl_offset;
-       int              upl_size;
+       int              upl_size;
        off_t            upl_f_offset;
        int              start_offset;
        int              start_pg;
@@ -4324,9 +4584,9 @@ advisory_read_ext(vnode_t vp, off_t filesize, off_t f_offset, int resid, int (*c
        int              retval = 0;
        int              issued_io;
        int              skip_range;
-       uint32_t         max_io_size;
-       
-       
+       uint32_t         max_io_size;
+
+
        if ( !UBCINFOEXISTS(vp))
                return(EINVAL);
 
@@ -4334,9 +4594,9 @@ advisory_read_ext(vnode_t vp, off_t filesize, off_t f_offset, int resid, int (*c
                return(EINVAL);
 
        max_io_size = cluster_max_io_size(vp->v_mount, CL_READ);
-       
+
        KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 60)) | DBG_FUNC_START,
-                       (int)f_offset, resid, (int)filesize, 0, 0);
+                    (int)f_offset, resid, (int)filesize, 0, 0);
 
        while (resid && f_offset < filesize && retval == 0) {
                /*
@@ -4390,7 +4650,7 @@ advisory_read_ext(vnode_t vp, off_t filesize, off_t f_offset, int resid, int (*c
                pages_in_upl = upl_size / PAGE_SIZE;
 
                KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 61)) | DBG_FUNC_START,
-                            (int)upl, (int)upl_f_offset, upl_size, start_offset, 0);
+                            upl, (int)upl_f_offset, upl_size, start_offset, 0);
 
                kret = ubc_create_upl(vp, 
                                      upl_f_offset,
@@ -4415,7 +4675,7 @@ advisory_read_ext(vnode_t vp, off_t filesize, off_t f_offset, int resid, int (*c
 
 
                KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 61)) | DBG_FUNC_END,
-                            (int)upl, (int)upl_f_offset, upl_size, start_offset, 0);
+                            upl, (int)upl_f_offset, upl_size, start_offset, 0);
 
 
                for (last_pg = 0; last_pg < pages_in_upl; ) {
@@ -4451,7 +4711,7 @@ advisory_read_ext(vnode_t vp, off_t filesize, off_t f_offset, int resid, int (*c
                                upl_offset = start_pg * PAGE_SIZE;
                                io_size    = (last_pg - start_pg) * PAGE_SIZE;
 
-                               if ((upl_f_offset + upl_offset + io_size) > filesize)
+                               if ((off_t)(upl_f_offset + upl_offset + io_size) > filesize)
                                        io_size = filesize - (upl_f_offset + upl_offset);
 
                                /*
@@ -4492,10 +4752,11 @@ int
 cluster_push_ext(vnode_t vp, int flags, int (*callback)(buf_t, void *), void *callback_arg)
 {
         int    retval;
+       int     my_sparse_wait = 0;
        struct  cl_writebehind *wbp;
 
        if ( !UBCINFOEXISTS(vp)) {
-               KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 53)) | DBG_FUNC_NONE, (int)vp, flags, 0, -1, 0);
+               KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 53)) | DBG_FUNC_NONE, vp, flags, 0, -1, 0);
                return (0);
        }
        /* return if deferred write is set */
@@ -4503,32 +4764,97 @@ cluster_push_ext(vnode_t vp, int flags, int (*callback)(buf_t, void *), void *ca
                return (0);
        }
        if ((wbp = cluster_get_wbp(vp, CLW_RETURNLOCKED)) == NULL) {
-               KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 53)) | DBG_FUNC_NONE, (int)vp, flags, 0, -2, 0);
+               KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 53)) | DBG_FUNC_NONE, vp, flags, 0, -2, 0);
                return (0);
        }
        if (wbp->cl_number == 0 && wbp->cl_scmap == NULL) {
                lck_mtx_unlock(&wbp->cl_lockw);
 
-               KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 53)) | DBG_FUNC_NONE, (int)vp, flags, 0, -3, 0);
+               KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 53)) | DBG_FUNC_NONE, vp, flags, 0, -3, 0);
                return(0);
        }
        KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 53)) | DBG_FUNC_START,
-                    (int)wbp->cl_scmap, wbp->cl_number, flags, 0, 0);
+                    wbp->cl_scmap, wbp->cl_number, flags, 0, 0);
+
+       /*
+        * if we have an fsync in progress, we don't want to allow any additional
+        * sync/fsync/close(s) to occur until it finishes.
+        * note that its possible for writes to continue to occur to this file
+        * while we're waiting and also once the fsync starts to clean if we're
+        * in the sparse map case
+        */
+       while (wbp->cl_sparse_wait) {
+               KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 97)) | DBG_FUNC_START, vp, 0, 0, 0, 0);
+
+               msleep((caddr_t)&wbp->cl_sparse_wait, &wbp->cl_lockw, PRIBIO + 1, "cluster_push_ext", NULL);
 
+               KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 97)) | DBG_FUNC_END, vp, 0, 0, 0, 0);
+       }
+       if (flags & IO_SYNC) {
+               my_sparse_wait = 1;
+               wbp->cl_sparse_wait = 1;
+
+               /*
+                * this is an fsync (or equivalent)... we must wait for any existing async
+                * cleaning operations to complete before we evaulate the current state
+                * and finish cleaning... this insures that all writes issued before this
+                * fsync actually get cleaned to the disk before this fsync returns
+                */
+               while (wbp->cl_sparse_pushes) {
+                       KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 98)) | DBG_FUNC_START, vp, 0, 0, 0, 0);
+
+                       msleep((caddr_t)&wbp->cl_sparse_pushes, &wbp->cl_lockw, PRIBIO + 1, "cluster_push_ext", NULL);
+
+                       KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 98)) | DBG_FUNC_END, vp, 0, 0, 0, 0);
+               }
+       }
        if (wbp->cl_scmap) {
-               sparse_cluster_push(wbp, vp, ubc_getsize(vp), PUSH_ALL | IO_PASSIVE, callback, callback_arg);
+               void    *scmap;
 
-               retval = 1;
-       } else 
-               retval = cluster_try_push(wbp, vp, ubc_getsize(vp), PUSH_ALL | IO_PASSIVE, callback, callback_arg);
+               if (wbp->cl_sparse_pushes < SPARSE_PUSH_LIMIT) {
+
+                       scmap = wbp->cl_scmap;
+                       wbp->cl_scmap = NULL;
+
+                       wbp->cl_sparse_pushes++;
+
+                       lck_mtx_unlock(&wbp->cl_lockw);
+
+                       sparse_cluster_push(&scmap, vp, ubc_getsize(vp), PUSH_ALL, flags | IO_PASSIVE, callback, callback_arg);
+
+                       lck_mtx_lock(&wbp->cl_lockw);
 
+                       wbp->cl_sparse_pushes--;
+                       
+                       if (wbp->cl_sparse_wait && wbp->cl_sparse_pushes == 0)
+                               wakeup((caddr_t)&wbp->cl_sparse_pushes);
+               } else {
+                       sparse_cluster_push(&(wbp->cl_scmap), vp, ubc_getsize(vp), PUSH_ALL, flags | IO_PASSIVE, callback, callback_arg);
+               }
+               retval = 1;
+       } else  {
+               retval = cluster_try_push(wbp, vp, ubc_getsize(vp), PUSH_ALL, flags | IO_PASSIVE, callback, callback_arg);
+       }
        lck_mtx_unlock(&wbp->cl_lockw);
 
        if (flags & IO_SYNC)
                (void)vnode_waitforwrites(vp, 0, 0, 0, "cluster_push");
 
+       if (my_sparse_wait) {
+               /*
+                * I'm the owner of the serialization token
+                * clear it and wakeup anyone that is waiting
+                * for me to finish
+                */
+               lck_mtx_lock(&wbp->cl_lockw);
+
+               wbp->cl_sparse_wait = 0;
+               wakeup((caddr_t)&wbp->cl_sparse_wait);
+
+               lck_mtx_unlock(&wbp->cl_lockw);
+       }
        KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 53)) | DBG_FUNC_END,
-                    (int)wbp->cl_scmap, wbp->cl_number, retval, 0, 0);
+                    wbp->cl_scmap, wbp->cl_number, retval, 0, 0);
 
        return (retval);
 }
@@ -4542,12 +4868,12 @@ cluster_release(struct ubc_info *ubc)
 
        if ((wbp = ubc->cl_wbehind)) {
 
-               KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 81)) | DBG_FUNC_START, (int)ubc, (int)wbp->cl_scmap, wbp->cl_scdirty, 0, 0);
+               KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 81)) | DBG_FUNC_START, ubc, wbp->cl_scmap, 0, 0, 0);
 
                if (wbp->cl_scmap)
                        vfs_drt_control(&(wbp->cl_scmap), 0);
        } else {
-               KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 81)) | DBG_FUNC_START, (int)ubc, 0, 0, 0, 0);
+               KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 81)) | DBG_FUNC_START, ubc, 0, 0, 0, 0);
        }
 
        rap = ubc->cl_rahead;
@@ -4563,12 +4889,12 @@ cluster_release(struct ubc_info *ubc)
        ubc->cl_rahead  = NULL;
        ubc->cl_wbehind = NULL;
 
-       KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 81)) | DBG_FUNC_END, (int)ubc, (int)rap, (int)wbp, 0, 0);
+       KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 81)) | DBG_FUNC_END, ubc, rap, wbp, 0, 0);
 }
 
 
 static int
-cluster_try_push(struct cl_writebehind *wbp, vnode_t vp, off_t EOF, int push_flag, int (*callback)(buf_t, void *), void *callback_arg)
+cluster_try_push(struct cl_writebehind *wbp, vnode_t vp, off_t EOF, int push_flag, int io_flags, int (*callback)(buf_t, void *), void *callback_arg)
 {
         int cl_index;
        int cl_index1;
@@ -4576,10 +4902,10 @@ cluster_try_push(struct cl_writebehind *wbp, vnode_t vp, off_t EOF, int push_fla
         int cl_len;
        int cl_pushed = 0;
        struct cl_wextent l_clusters[MAX_CLUSTERS];
-       u_int  max_cluster_pgcount;
-       
-       max_cluster_pgcount = MAX_CLUSTER_SIZE(vp) / PAGE_SIZE;
+       u_int  max_cluster_pgcount;
+
+
+       max_cluster_pgcount = MAX_CLUSTER_SIZE(vp) / PAGE_SIZE;
        /*
         * the write behind context exists and has
         * already been locked...
@@ -4607,6 +4933,7 @@ cluster_try_push(struct cl_writebehind *wbp, vnode_t vp, off_t EOF, int push_fla
                }
                if (min_index == -1)
                        break;
+
                l_clusters[cl_index].b_addr = wbp->cl_clusters[min_index].b_addr;
                l_clusters[cl_index].e_addr = wbp->cl_clusters[min_index].e_addr;
                l_clusters[cl_index].io_flags = wbp->cl_clusters[min_index].io_flags;
@@ -4646,32 +4973,19 @@ cluster_try_push(struct cl_writebehind *wbp, vnode_t vp, off_t EOF, int push_fla
                                goto dont_try;
                }
        }
-       /*
-        * drop the lock while we're firing off the I/Os...
-        * this is safe since I'm working off of a private sorted copy
-        * of the clusters, and I'm going to re-evaluate the public
-        * state after I retake the lock
-        *
-        * we need to drop it to avoid a lock inversion when trying to
-        * grab pages into the UPL... another thread in 'write' may
-        * have these pages in its UPL and be blocked trying to
-        * gain the write-behind lock for this vnode
-        */
-       lck_mtx_unlock(&wbp->cl_lockw);
-
        for (cl_index = 0; cl_index < cl_len; cl_index++) {
                int     flags;
                struct  cl_extent cl;
 
+               flags = io_flags & (IO_PASSIVE|IO_CLOSE);
+
                /*
                 * try to push each cluster in turn...
                 */
                if (l_clusters[cl_index].io_flags & CLW_IONOCACHE)
-                       flags = IO_NOCACHE;
-               else
-                       flags = 0;
+                       flags |= IO_NOCACHE;
 
-               if ((l_clusters[cl_index].io_flags & CLW_IOPASSIVE) || (push_flag & IO_PASSIVE))
+               if (l_clusters[cl_index].io_flags & CLW_IOPASSIVE)
                        flags |= IO_PASSIVE;
 
                if (push_flag & PUSH_SYNC)
@@ -4690,8 +5004,6 @@ cluster_try_push(struct cl_writebehind *wbp, vnode_t vp, off_t EOF, int push_fla
                if ( !(push_flag & PUSH_ALL) )
                        break;
        }
-       lck_mtx_lock(&wbp->cl_lockw);
-
 dont_try:
        if (cl_len > cl_pushed) {
               /*
@@ -4778,9 +5090,9 @@ cluster_push_now(vnode_t vp, struct cl_extent *cl, off_t EOF, int flags, int (*c
        kern_return_t    kret;
 
        if (flags & IO_PASSIVE)
-           bflag = CL_PASSIVE;
+               bflag = CL_PASSIVE;
        else
-           bflag = 0;
+               bflag = 0;
 
        KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 51)) | DBG_FUNC_START,
                     (int)cl->b_addr, (int)cl->e_addr, (int)EOF, flags, 0);
@@ -4840,7 +5152,7 @@ cluster_push_now(vnode_t vp, struct cl_extent *cl, off_t EOF, int flags, int (*c
        if (kret != KERN_SUCCESS)
                panic("cluster_push: failed to get pagelist");
 
-       KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 41)) | DBG_FUNC_END, (int)upl, upl_f_offset, 0, 0, 0);
+       KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 41)) | DBG_FUNC_END, upl, upl_f_offset, 0, 0, 0);
 
        /*
         * since we only asked for the dirty pages back
@@ -4907,6 +5219,9 @@ cluster_push_now(vnode_t vp, struct cl_extent *cl, off_t EOF, int flags, int (*c
                if ( !(flags & IO_SYNC))
                        io_flags |= CL_ASYNC;
 
+               if (flags & IO_CLOSE)
+                       io_flags |= CL_CLOSE;
+
                retval = cluster_io(vp, upl, upl_offset, upl_f_offset + upl_offset, io_size,
                                    io_flags, (buf_t)NULL, (struct clios *)NULL, callback, callback_arg);
 
@@ -4929,10 +5244,7 @@ sparse_cluster_switch(struct cl_writebehind *wbp, vnode_t vp, off_t EOF, int (*c
 {
         int    cl_index;
 
-       KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 78)) | DBG_FUNC_START, (int)vp, (int)wbp->cl_scmap, wbp->cl_scdirty, 0, 0);
-
-       if (wbp->cl_scmap == NULL)
-               wbp->cl_scdirty = 0;
+       KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 78)) | DBG_FUNC_START, vp, wbp->cl_scmap, 0, 0, 0);
 
        for (cl_index = 0; cl_index < wbp->cl_number; cl_index++) {
                int       flags;
@@ -4944,62 +5256,47 @@ sparse_cluster_switch(struct cl_writebehind *wbp, vnode_t vp, off_t EOF, int (*c
                                if (flags & UPL_POP_DIRTY) {
                                        cl.e_addr = cl.b_addr + 1;
 
-                                       sparse_cluster_add(wbp, vp, &cl, EOF, callback, callback_arg);
+                                       sparse_cluster_add(&(wbp->cl_scmap), vp, &cl, EOF, callback, callback_arg);
                                }
                        }
                }
        }
        wbp->cl_number = 0;
 
-       KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 78)) | DBG_FUNC_END, (int)vp, (int)wbp->cl_scmap, wbp->cl_scdirty, 0, 0);
+       KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 78)) | DBG_FUNC_END, vp, wbp->cl_scmap, 0, 0, 0);
 }
 
 
 /*
- * sparse_cluster_push is called with the write behind lock held
+ * sparse_cluster_push must be called with the write-behind lock held if the scmap is
+ * still associated with the write-behind context... however, if the scmap has been disassociated
+ * from the write-behind context (the cluster_push case), the wb lock is not held
  */
 static void
-sparse_cluster_push(struct cl_writebehind *wbp, vnode_t vp, off_t EOF, int push_flag, int (*callback)(buf_t, void *), void *callback_arg)
+sparse_cluster_push(void **scmap, vnode_t vp, off_t EOF, int push_flag, int io_flags, int (*callback)(buf_t, void *), void *callback_arg)
 {
         struct cl_extent cl;
         off_t          offset;
        u_int           length;
 
-       KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 79)) | DBG_FUNC_START, (int)vp, (int)wbp->cl_scmap, wbp->cl_scdirty, push_flag, 0);
+       KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 79)) | DBG_FUNC_START, vp, (*scmap), 0, push_flag, 0);
 
        if (push_flag & PUSH_ALL)
-               vfs_drt_control(&(wbp->cl_scmap), 1);
+               vfs_drt_control(scmap, 1);
 
        for (;;) {
-               if (vfs_drt_get_cluster(&(wbp->cl_scmap), &offset, &length) != KERN_SUCCESS)
+               if (vfs_drt_get_cluster(scmap, &offset, &length) != KERN_SUCCESS)
                        break;
 
                cl.b_addr = (daddr64_t)(offset / PAGE_SIZE_64);
                cl.e_addr = (daddr64_t)((offset + length) / PAGE_SIZE_64);
 
-               wbp->cl_scdirty -= (int)(cl.e_addr - cl.b_addr);
-
-               /*
-                * drop the lock while we're firing off the I/Os...
-                * this is safe since I've already updated the state
-                * this lock is protecting and I'm going to re-evaluate
-                * the public state after I retake the lock
-                *
-                * we need to drop it to avoid a lock inversion when trying to
-                * grab pages into the UPL... another thread in 'write' may
-                * have these pages in its UPL and be blocked trying to
-                * gain the write-behind lock for this vnode
-                */
-               lck_mtx_unlock(&wbp->cl_lockw);
-
-               cluster_push_now(vp, &cl, EOF, push_flag & IO_PASSIVE, callback, callback_arg);
-
-               lck_mtx_lock(&wbp->cl_lockw);
+               cluster_push_now(vp, &cl, EOF, io_flags & (IO_PASSIVE|IO_CLOSE), callback, callback_arg);
 
                if ( !(push_flag & PUSH_ALL) )
                        break;
        }
-       KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 79)) | DBG_FUNC_END, (int)vp, (int)wbp->cl_scmap, wbp->cl_scdirty, 0, 0);
+       KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 79)) | DBG_FUNC_END, vp, (*scmap), 0, 0, 0);
 }
 
 
@@ -5007,33 +5304,29 @@ sparse_cluster_push(struct cl_writebehind *wbp, vnode_t vp, off_t EOF, int push_
  * sparse_cluster_add is called with the write behind lock held
  */
 static void
-sparse_cluster_add(struct cl_writebehind *wbp, vnode_t vp, struct cl_extent *cl, off_t EOF, int (*callback)(buf_t, void *), void *callback_arg)
+sparse_cluster_add(void **scmap, vnode_t vp, struct cl_extent *cl, off_t EOF, int (*callback)(buf_t, void *), void *callback_arg)
 {
         u_int  new_dirty;
        u_int   length;
        off_t   offset;
 
-       KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 80)) | DBG_FUNC_START, (int)wbp->cl_scmap, wbp->cl_scdirty, (int)cl->b_addr, (int)cl->e_addr, 0);
+       KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 80)) | DBG_FUNC_START, (*scmap), 0, cl->b_addr, (int)cl->e_addr, 0);
 
        offset = (off_t)(cl->b_addr * PAGE_SIZE_64);
        length = ((u_int)(cl->e_addr - cl->b_addr)) * PAGE_SIZE;
 
-       while (vfs_drt_mark_pages(&(wbp->cl_scmap), offset, length, &new_dirty) != KERN_SUCCESS) {
+       while (vfs_drt_mark_pages(scmap, offset, length, &new_dirty) != KERN_SUCCESS) {
                /*
                 * no room left in the map
                 * only a partial update was done
                 * push out some pages and try again
                 */
-               wbp->cl_scdirty += new_dirty;
-
-               sparse_cluster_push(wbp, vp, EOF, 0, callback, callback_arg);
+               sparse_cluster_push(scmap, vp, EOF, 0, 0, callback, callback_arg);
 
                offset += (new_dirty * PAGE_SIZE_64);
                length -= (new_dirty * PAGE_SIZE);
        }
-       wbp->cl_scdirty += new_dirty;
-
-       KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 80)) | DBG_FUNC_END, (int)vp, (int)wbp->cl_scmap, wbp->cl_scdirty, 0, 0);
+       KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 80)) | DBG_FUNC_END, vp, (*scmap), 0, 0, 0);
 }
 
 
@@ -5051,9 +5344,9 @@ cluster_align_phys_io(vnode_t vp, struct uio *uio, addr64_t usr_paddr, u_int32_t
        int              bflag;
 
        if (flags & IO_PASSIVE)
-           bflag = CL_PASSIVE;
+               bflag = CL_PASSIVE;
        else
-           bflag = 0;
+               bflag = 0;
 
        upl_flags = UPL_SET_LITE;
 
@@ -5167,17 +5460,10 @@ cluster_copy_upl_data(struct uio *uio, upl_t upl, int upl_offset, int *io_resid)
                uio->uio_segflg = UIO_PHYS_USERSPACE64;
                break;
 
-         case UIO_SYSSPACE32:
-               uio->uio_segflg = UIO_PHYS_SYSSPACE32;
-               break;
-
          case UIO_SYSSPACE:
                uio->uio_segflg = UIO_PHYS_SYSSPACE;
                break;
 
-         case UIO_SYSSPACE64:
-               uio->uio_segflg = UIO_PHYS_SYSSPACE64;
-               break;
        }
        pl = ubc_upl_pageinfo(upl);
 
@@ -5229,7 +5515,7 @@ cluster_copy_ubc_data_internal(vnode_t vp, struct uio *uio, int *io_resid, int m
        io_size = *io_resid;
 
        KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 34)) | DBG_FUNC_START,
-                    (int)uio->uio_offset, 0, io_size, 0, 0);
+                    (int)uio->uio_offset, io_size, mark_dirty, take_reference, 0);
 
        control = ubc_getobject(vp, UBC_FLAGS_NONE);
 
@@ -5253,14 +5539,6 @@ cluster_copy_ubc_data_internal(vnode_t vp, struct uio *uio, int *io_resid, int m
                uio->uio_segflg = UIO_PHYS_USERSPACE64;
                break;
 
-         case UIO_SYSSPACE32:
-               uio->uio_segflg = UIO_PHYS_SYSSPACE32;
-               break;
-
-         case UIO_SYSSPACE64:
-               uio->uio_segflg = UIO_PHYS_SYSSPACE64;
-               break;
-
          case UIO_USERSPACE:
          case UIO_USERISPACE:
                uio->uio_segflg = UIO_PHYS_USERSPACE;
@@ -5393,6 +5671,14 @@ is_file_clean(vnode_t vp, off_t filesize)
 #define DRT_HASH_SMALL_MODULUS 23
 #define DRT_HASH_LARGE_MODULUS 401
 
+/*
+ * Physical memory required before the large hash modulus is permitted.
+ *
+ * On small memory systems, the large hash modulus can lead to phsyical
+ * memory starvation, so we avoid using it there.
+ */
+#define DRT_HASH_LARGE_MEMORY_REQUIRED (1024LL * 1024LL * 1024LL)      /* 1GiB */
+
 #define DRT_SMALL_ALLOCATION   1024    /* 104 bytes spare */
 #define DRT_LARGE_ALLOCATION   16384   /* 344 bytes spare */
 
@@ -5535,8 +5821,12 @@ vfs_drt_alloc_map(struct vfs_drt_clustermap **cmapp)
                 * see whether we should grow to the large one.
                 */
                if (ocmap->scm_modulus == DRT_HASH_SMALL_MODULUS) {
-                       /* if the ring is nearly full */
-                       if (active_buckets > (DRT_HASH_SMALL_MODULUS - 5)) {
+                       /* 
+                        * If the ring is nearly full and we are allowed to
+                        * use the large modulus, upgrade.
+                        */
+                       if ((active_buckets > (DRT_HASH_SMALL_MODULUS - 5)) &&
+                           (max_mem >= DRT_HASH_LARGE_MEMORY_REQUIRED)) {
                                nsize = DRT_HASH_LARGE_MODULUS;
                        } else {
                                nsize = DRT_HASH_SMALL_MODULUS;