[XFS] 929045 567344 This mod re-organizes some of the in-core file extent

code to prepare for an upcoming mod which will introduce multi-level
in-core extent allocations. Although the in-core extent management is
using a new code path in this mod, the functionality remains the same. 
Major changes include:	- Introduce 10 new subroutines which re-orgainze
the existing code but	do NOT change functionality:	    
xfs_iext_get_ext()	   xfs_iext_insert()	     xfs_iext_add()	  
 xfs_iext_remove()	   xfs_iext_remove_inline()	   
xfs_iext_remove_direct()	 xfs_iext_realloc_direct()	  
xfs_iext_direct_to_inline()	    xfs_iext_inline_to_direct()        
xfs_iext_destroy() - Remove 2 subroutines (functionality moved to new
subroutines above):	    xfs_iext_realloc() -replaced by xfs_iext_add()
and xfs_iext_remove()	      xfs_bmap_insert_exlist() - replaced by
xfs_iext_insert()	  xfs_bmap_delete_exlist() - replaced by
xfs_iext_remove() - Replace all hard-coded (indexed) extent assignments
with a call to	 xfs_iext_get_ext() - Replace all extent record pointer
arithmetic (ep++, ep--, base + lastx,..)   with calls to
xfs_iext_get_ext() - Update comments to remove the idea of a single
"extent list" and   introduce "extent record" terminology instead

SGI-PV: 928864
SGI-Modid: xfs-linux-melb:xfs-kern:207390a

Signed-off-by: Mandy Kirkconnell <alkirkco@sgi.com>
Signed-off-by: Nathan Scott <nathans@sgi.com>

1 files changed, 351 insertions, 119 deletions

diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index 1d7f5a7e063e..6459395a0e40 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -76,16 +76,18 @@ STATIC int xfs_iformat_btree(xfs_inode_t *, xfs_dinode_t *, int);
  */
 STATIC void
 xfs_validate_extents(
-        xfs_bmbt_rec_t          *ep,
+        xfs_ifork_t             *ifp,
         int                     nrecs,
         int                     disk,
         xfs_exntfmt_t           fmt)
 {
+        xfs_bmbt_rec_t          *ep;
         xfs_bmbt_irec_t         irec;
         xfs_bmbt_rec_t          rec;
         int                     i;
 
         for (i = 0; i < nrecs; i++) {
+                ep = xfs_iext_get_ext(ifp, i);
                 rec.l0 = get_unaligned((__uint64_t*)&ep->l0);
                 rec.l1 = get_unaligned((__uint64_t*)&ep->l1);
                 if (disk)
@@ -94,11 +96,10 @@ xfs_validate_extents(
                         xfs_bmbt_get_all(&rec, &irec);
                 if (fmt == XFS_EXTFMT_NOSTATE)
                         ASSERT(irec.br_state == XFS_EXT_NORM);
-                ep++;
         }
 }
 #else /* DEBUG */
-#define xfs_validate_extents(ep, nrecs, disk, fmt)
+#define xfs_validate_extents(ifp, nrecs, disk, fmt)
 #endif /* DEBUG */
 
 /*
@@ -597,7 +598,6 @@ xfs_iformat_extents(
         xfs_bmbt_rec_t  *ep, *dp;
         xfs_ifork_t     *ifp;
         int             nex;
-        int             real_size;
         int             size;
         int             i;
 
@@ -619,23 +619,20 @@ xfs_iformat_extents(
                 return XFS_ERROR(EFSCORRUPTED);
         }
 
-        real_size = 0;
+        ifp->if_real_bytes = 0;
         if (nex == 0)
                 ifp->if_u1.if_extents = NULL;
         else if (nex <= XFS_INLINE_EXTS)
                 ifp->if_u1.if_extents = ifp->if_u2.if_inline_ext;
-        else {
-                ifp->if_u1.if_extents = kmem_alloc(size, KM_SLEEP);
-                ASSERT(ifp->if_u1.if_extents != NULL);
-                real_size = size;
-        }
+        else
+                xfs_iext_add(ifp, 0, nex);
+
         ifp->if_bytes = size;
-        ifp->if_real_bytes = real_size;
         if (size) {
                 dp = (xfs_bmbt_rec_t *) XFS_DFORK_PTR(dip, whichfork);
-                xfs_validate_extents(dp, nex, 1, XFS_EXTFMT_INODE(ip));
-                ep = ifp->if_u1.if_extents;
-                for (i = 0; i < nex; i++, ep++, dp++) {
+                xfs_validate_extents(ifp, nex, 1, XFS_EXTFMT_INODE(ip));
+                for (i = 0; i < nex; i++, dp++) {
+                        ep = xfs_iext_get_ext(ifp, i);
                         ep->l0 = INT_GET(get_unaligned((__uint64_t*)&dp->l0),
                                                                 ARCH_CONVERT);
                         ep->l1 = INT_GET(get_unaligned((__uint64_t*)&dp->l1),
@@ -646,7 +643,7 @@ xfs_iformat_extents(
                 if (whichfork != XFS_DATA_FORK ||
                         XFS_EXTFMT_INODE(ip) == XFS_EXTFMT_NOSTATE)
                                 if (unlikely(xfs_check_nostate_extents(
-                                    ifp->if_u1.if_extents, nex))) {
+                                    ifp, 0, nex))) {
                                         XFS_ERROR_REPORT("xfs_iformat_extents(2)",
                                                          XFS_ERRLEVEL_LOW,
                                                          ip->i_mount);
@@ -1015,6 +1012,7 @@ xfs_iread_extents(
 {
         int             error;
         xfs_ifork_t     *ifp;
+        xfs_extnum_t    nextents;
         size_t          size;
 
         if (unlikely(XFS_IFORK_FORMAT(ip, whichfork) != XFS_DINODE_FMT_BTREE)) {
@@ -1022,26 +1020,24 @@ xfs_iread_extents(
                                  ip->i_mount);
                 return XFS_ERROR(EFSCORRUPTED);
         }
-        size = XFS_IFORK_NEXTENTS(ip, whichfork) * (uint)sizeof(xfs_bmbt_rec_t);
+        nextents = XFS_IFORK_NEXTENTS(ip, whichfork);
+        size = nextents * sizeof(xfs_bmbt_rec_t);
         ifp = XFS_IFORK_PTR(ip, whichfork);
+
         /*
          * We know that the size is valid (it's checked in iformat_btree)
          */
-        ifp->if_u1.if_extents = kmem_alloc(size, KM_SLEEP);
-        ASSERT(ifp->if_u1.if_extents != NULL);
         ifp->if_lastex = NULLEXTNUM;
-        ifp->if_bytes = ifp->if_real_bytes = (int)size;
+        ifp->if_bytes = ifp->if_real_bytes = 0;
         ifp->if_flags |= XFS_IFEXTENTS;
+        xfs_iext_add(ifp, 0, nextents);
         error = xfs_bmap_read_extents(tp, ip, whichfork);
         if (error) {
-                kmem_free(ifp->if_u1.if_extents, size);
-                ifp->if_u1.if_extents = NULL;
-                ifp->if_bytes = ifp->if_real_bytes = 0;
+                xfs_iext_destroy(ifp);
                 ifp->if_flags &= ~XFS_IFEXTENTS;
                 return error;
         }
-        xfs_validate_extents((xfs_bmbt_rec_t *)ifp->if_u1.if_extents,
-                XFS_IFORK_NEXTENTS(ip, whichfork), 0, XFS_EXTFMT_INODE(ip));
+        xfs_validate_extents(ifp, nextents, 0, XFS_EXTFMT_INODE(ip));
         return 0;
 }
 
@@ -2476,92 +2472,6 @@ xfs_iroot_realloc(
 
 
 /*
- * This is called when the amount of space needed for if_extents
- * is increased or decreased.  The change in size is indicated by
- * the number of extents that need to be added or deleted in the
- * ext_diff parameter.
- *
- * If the amount of space needed has decreased below the size of the
- * inline buffer, then switch to using the inline buffer.  Otherwise,
- * use kmem_realloc() or kmem_alloc() to adjust the size of the buffer
- * to what is needed.
- *
- * ip -- the inode whose if_extents area is changing
- * ext_diff -- the change in the number of extents, positive or negative,
- *       requested for the if_extents array.
- */
-void
-xfs_iext_realloc(
-        xfs_inode_t     *ip,
-        int             ext_diff,
-        int             whichfork)
-{
-        int             byte_diff;
-        xfs_ifork_t     *ifp;
-        int             new_size;
-        uint            rnew_size;
-
-        if (ext_diff == 0) {
-                return;
-        }
-
-        ifp = XFS_IFORK_PTR(ip, whichfork);
-        byte_diff = ext_diff * (uint)sizeof(xfs_bmbt_rec_t);
-        new_size = (int)ifp->if_bytes + byte_diff;
-        ASSERT(new_size >= 0);
-
-        if (new_size == 0) {
-                if (ifp->if_u1.if_extents != ifp->if_u2.if_inline_ext) {
-                        ASSERT(ifp->if_real_bytes != 0);
-                        kmem_free(ifp->if_u1.if_extents, ifp->if_real_bytes);
-                }
-                ifp->if_u1.if_extents = NULL;
-                rnew_size = 0;
-        } else if (new_size <= sizeof(ifp->if_u2.if_inline_ext)) {
-                /*
-                 * If the valid extents can fit in if_inline_ext,
-                 * copy them from the malloc'd vector and free it.
-                 */
-                if (ifp->if_u1.if_extents != ifp->if_u2.if_inline_ext) {
-                        /*
-                         * For now, empty files are format EXTENTS,
-                         * so the if_extents pointer is null.
-                         */
-                        if (ifp->if_u1.if_extents) {
-                                memcpy(ifp->if_u2.if_inline_ext,
-                                        ifp->if_u1.if_extents, new_size);
-                                kmem_free(ifp->if_u1.if_extents,
-                                          ifp->if_real_bytes);
-                        }
-                        ifp->if_u1.if_extents = ifp->if_u2.if_inline_ext;
-                }
-                rnew_size = 0;
-        } else {
-                rnew_size = new_size;
-                if ((rnew_size & (rnew_size - 1)) != 0)
-                        rnew_size = xfs_iroundup(rnew_size);
-                /*
-                 * Stuck with malloc/realloc.
-                 */
-                if (ifp->if_u1.if_extents == ifp->if_u2.if_inline_ext) {
-                        ifp->if_u1.if_extents = (xfs_bmbt_rec_t *)
-                                kmem_alloc(rnew_size, KM_SLEEP);
-                        memcpy(ifp->if_u1.if_extents, ifp->if_u2.if_inline_ext,
-                              sizeof(ifp->if_u2.if_inline_ext));
-                } else if (rnew_size != ifp->if_real_bytes) {
-                        ifp->if_u1.if_extents = (xfs_bmbt_rec_t *)
-                          kmem_realloc(ifp->if_u1.if_extents,
-                                        rnew_size,
-                                        ifp->if_real_bytes,
-                                        KM_NOFS);
-                }
-        }
-        ifp->if_real_bytes = rnew_size;
-        ifp->if_bytes = new_size;
-}
-
-
-/*
  * This is called when the amount of space needed for if_data
  * is increased or decreased.  The change in size is indicated by
  * the number of bytes that need to be added or deleted in the
@@ -2723,9 +2633,7 @@ xfs_idestroy_fork(
                    (ifp->if_u1.if_extents != NULL) &&
                    (ifp->if_u1.if_extents != ifp->if_u2.if_inline_ext)) {
                 ASSERT(ifp->if_real_bytes != 0);
-                kmem_free(ifp->if_u1.if_extents, ifp->if_real_bytes);
-                ifp->if_u1.if_extents = NULL;
-                ifp->if_real_bytes = 0;
+                xfs_iext_destroy(ifp);
         }
         ASSERT(ifp->if_u1.if_extents == NULL ||
                ifp->if_u1.if_extents == ifp->if_u2.if_inline_ext);
@@ -2902,16 +2810,15 @@ xfs_iextents_copy(
          * the delayed ones.  There must be at least one
          * non-delayed extent.
          */
-        ep = ifp->if_u1.if_extents;
         dest_ep = buffer;
         copied = 0;
         for (i = 0; i < nrecs; i++) {
+                ep = xfs_iext_get_ext(ifp, i);
                 start_block = xfs_bmbt_get_startblock(ep);
                 if (ISNULLSTARTBLOCK(start_block)) {
                         /*
                          * It's a delayed allocation extent, so skip it.
                          */
-                        ep++;
                         continue;
                 }
 
@@ -2921,11 +2828,10 @@ xfs_iextents_copy(
                 put_unaligned(INT_GET(ep->l1, ARCH_CONVERT),
                               (__uint64_t*)&dest_ep->l1);
                 dest_ep++;
-                ep++;
                 copied++;
         }
         ASSERT(copied != 0);
-        xfs_validate_extents(buffer, copied, 1, XFS_EXTFMT_INODE(ip));
+        xfs_validate_extents(ifp, copied, 1, XFS_EXTFMT_INODE(ip));
 
         return (copied * (uint)sizeof(xfs_bmbt_rec_t));
 }
@@ -2995,8 +2901,10 @@ xfs_iflush_fork(
         case XFS_DINODE_FMT_EXTENTS:
                 ASSERT((ifp->if_flags & XFS_IFEXTENTS) ||
                        !(iip->ili_format.ilf_fields & extflag[whichfork]));
-                ASSERT((ifp->if_u1.if_extents != NULL) || (ifp->if_bytes == 0));
-                ASSERT((ifp->if_u1.if_extents == NULL) || (ifp->if_bytes > 0));
+                ASSERT((xfs_iext_get_ext(ifp, 0) != NULL) ||
+                        (ifp->if_bytes == 0));
+                ASSERT((xfs_iext_get_ext(ifp, 0) == NULL) ||
+                        (ifp->if_bytes > 0));
                 if ((iip->ili_format.ilf_fields & extflag[whichfork]) &&
                     (ifp->if_bytes > 0)) {
                         ASSERT(XFS_IFORK_NEXTENTS(ip, whichfork) > 0);
@@ -3704,3 +3612,327 @@ xfs_ilock_trace(xfs_inode_t *ip, int lock, unsigned int lockflags, inst_t *ra)
                      NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL);
 }
 #endif
+
+/*
+ * Return a pointer to the extent record at file index idx.
+ */
+xfs_bmbt_rec_t *
+xfs_iext_get_ext(
+        xfs_ifork_t     *ifp,           /* inode fork pointer */
+        xfs_extnum_t    idx)            /* index of target extent */
+{
+        ASSERT(idx >= 0);
+        if (ifp->if_bytes) {
+                return &ifp->if_u1.if_extents[idx];
+        } else {
+                return NULL;
+        }
+}
+
+/*
+ * Insert new item(s) into the extent records for incore inode
+ * fork 'ifp'.  'count' new items are inserted at index 'idx'.
+ */
+void
+xfs_iext_insert(
+        xfs_ifork_t     *ifp,           /* inode fork pointer */
+        xfs_extnum_t    idx,            /* starting index of new items */
+        xfs_extnum_t    count,          /* number of inserted items */
+        xfs_bmbt_irec_t *new)           /* items to insert */
+{
+        xfs_bmbt_rec_t  *ep;            /* extent record pointer */
+        xfs_extnum_t    i;              /* extent record index */
+
+        ASSERT(ifp->if_flags & XFS_IFEXTENTS);
+        xfs_iext_add(ifp, idx, count);
+        for (i = idx; i < idx + count; i++, new++) {
+                ep = xfs_iext_get_ext(ifp, i);
+                xfs_bmbt_set_all(ep, new);
+        }
+}
+
+/*
+ * This is called when the amount of space required for incore file
+ * extents needs to be increased. The ext_diff parameter stores the
+ * number of new extents being added and the idx parameter contains
+ * the extent index where the new extents will be added. If the new
+ * extents are being appended, then we just need to (re)allocate and
+ * initialize the space. Otherwise, if the new extents are being
+ * inserted into the middle of the existing entries, a bit more work
+ * is required to make room for the new extents to be inserted. The
+ * caller is responsible for filling in the new extent entries upon
+ * return.
+ */
+void
+xfs_iext_add(
+        xfs_ifork_t     *ifp,           /* inode fork pointer */
+        xfs_extnum_t    idx,            /* index to begin adding exts */
+        int             ext_diff)       /* nubmer of extents to add */
+{
+        int             byte_diff;      /* new bytes being added */
+        int             new_size;       /* size of extents after adding */
+        xfs_extnum_t    nextents;       /* number of extents in file */
+
+        nextents = ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t);
+        ASSERT((idx >= 0) && (idx <= nextents));
+        byte_diff = ext_diff * sizeof(xfs_bmbt_rec_t);
+        new_size = ifp->if_bytes + byte_diff;
+        /*
+         * If the new number of extents (nextents + ext_diff)
+         * fits inside the inode, then continue to use the inline
+         * extent buffer.
+         */
+        if (nextents + ext_diff <= XFS_INLINE_EXTS) {
+                if (idx < nextents) {
+                        memmove(&ifp->if_u2.if_inline_ext[idx + ext_diff],
+                                &ifp->if_u2.if_inline_ext[idx],
+                                (nextents - idx) * sizeof(xfs_bmbt_rec_t));
+                        memset(&ifp->if_u2.if_inline_ext[idx], 0, byte_diff);
+                }
+                ifp->if_u1.if_extents = ifp->if_u2.if_inline_ext;
+                ifp->if_real_bytes = 0;
+        }
+        /*
+         * Otherwise use a linear (direct) extent list.
+         * If the extents are currently inside the inode,
+         * xfs_iext_realloc_direct will switch us from
+         * inline to direct extent allocation mode.
+         */
+        else {
+                xfs_iext_realloc_direct(ifp, new_size);
+                if (idx < nextents) {
+                        memmove(&ifp->if_u1.if_extents[idx + ext_diff],
+                                &ifp->if_u1.if_extents[idx],
+                                (nextents - idx) * sizeof(xfs_bmbt_rec_t));
+                        memset(&ifp->if_u1.if_extents[idx], 0, byte_diff);
+                }
+        }
+        ifp->if_bytes = new_size;
+}
+
+/*
+ * This is called when the amount of space required for incore file
+ * extents needs to be decreased. The ext_diff parameter stores the
+ * number of extents to be removed and the idx parameter contains
+ * the extent index where the extents will be removed from.
+ */
+void
+xfs_iext_remove(
+        xfs_ifork_t     *ifp,           /* inode fork pointer */
+        xfs_extnum_t    idx,            /* index to begin removing exts */
+        int             ext_diff)       /* number of extents to remove */
+{
+        xfs_extnum_t    nextents;       /* number of extents in file */
+        int             new_size;       /* size of extents after removal */
+
+        ASSERT(ext_diff > 0);
+        nextents = ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t);
+        new_size = (nextents - ext_diff) * sizeof(xfs_bmbt_rec_t);
+
+        if (new_size == 0) {
+                xfs_iext_destroy(ifp);
+        } else if (ifp->if_real_bytes) {
+                xfs_iext_remove_direct(ifp, idx, ext_diff);
+        } else {
+                xfs_iext_remove_inline(ifp, idx, ext_diff);
+        }
+        ifp->if_bytes = new_size;
+}
+
+/*
+ * This removes ext_diff extents from the inline buffer, beginning
+ * at extent index idx.
+ */
+void
+xfs_iext_remove_inline(
+        xfs_ifork_t     *ifp,           /* inode fork pointer */
+        xfs_extnum_t    idx,            /* index to begin removing exts */
+        int             ext_diff)       /* number of extents to remove */
+{
+        int             nextents;       /* number of extents in file */
+
+        ASSERT(idx < XFS_INLINE_EXTS);
+        nextents = ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t);
+        ASSERT(((nextents - ext_diff) > 0) &&
+                (nextents - ext_diff) < XFS_INLINE_EXTS);
+
+        if (idx + ext_diff < nextents) {
+                memmove(&ifp->if_u2.if_inline_ext[idx],
+                        &ifp->if_u2.if_inline_ext[idx + ext_diff],
+                        (nextents - (idx + ext_diff)) *
+                         sizeof(xfs_bmbt_rec_t));
+                memset(&ifp->if_u2.if_inline_ext[nextents - ext_diff],
+                        0, ext_diff * sizeof(xfs_bmbt_rec_t));
+        } else {
+                memset(&ifp->if_u2.if_inline_ext[idx], 0,
+                        ext_diff * sizeof(xfs_bmbt_rec_t));
+        }
+}
+
+/*
+ * This removes ext_diff extents from a linear (direct) extent list,
+ * beginning at extent index idx. If the extents are being removed
+ * from the end of the list (ie. truncate) then we just need to re-
+ * allocate the list to remove the extra space. Otherwise, if the
+ * extents are being removed from the middle of the existing extent
+ * entries, then we first need to move the extent records beginning
+ * at idx + ext_diff up in the list to overwrite the records being
+ * removed, then remove the extra space via kmem_realloc.
+ */
+void
+xfs_iext_remove_direct(
+        xfs_ifork_t     *ifp,           /* inode fork pointer */
+        xfs_extnum_t    idx,            /* index to begin removing exts */
+        int             ext_diff)       /* number of extents to remove */
+{
+        xfs_extnum_t    nextents;       /* number of extents in file */
+        int             new_size;       /* size of extents after removal */
+
+        new_size = ifp->if_bytes -
+                (ext_diff * sizeof(xfs_bmbt_rec_t));
+        nextents = ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t);
+
+        if (new_size == 0) {
+                xfs_iext_destroy(ifp);
+                return;
+        }
+        /* Move extents up in the list (if needed) */
+        if (idx + ext_diff < nextents) {
+                memmove(&ifp->if_u1.if_extents[idx],
+                        &ifp->if_u1.if_extents[idx + ext_diff],
+                        (nextents - (idx + ext_diff)) *
+                         sizeof(xfs_bmbt_rec_t));
+        }
+        memset(&ifp->if_u1.if_extents[nextents - ext_diff],
+                0, ext_diff * sizeof(xfs_bmbt_rec_t));
+        /*
+         * Reallocate the direct extent list. If the extents
+         * will fit inside the inode then xfs_iext_realloc_direct
+         * will switch from direct to inline extent allocation
+         * mode for us.
+         */
+        xfs_iext_realloc_direct(ifp, new_size);
+        ifp->if_bytes = new_size;
+}
+
+/*
+ * Create, destroy, or resize a linear (direct) block of extents.
+ */
+void
+xfs_iext_realloc_direct(
+        xfs_ifork_t     *ifp,           /* inode fork pointer */
+        int             new_size)       /* new size of extents */
+{
+        int             rnew_size;      /* real new size of extents */
+
+        rnew_size = new_size;
+
+        /* Free extent records */
+        if (new_size == 0) {
+                xfs_iext_destroy(ifp);
+        }
+        /* Resize direct extent list and zero any new bytes */
+        else if (ifp->if_real_bytes) {
+                /* Check if extents will fit inside the inode */
+                if (new_size <= XFS_INLINE_EXTS * sizeof(xfs_bmbt_rec_t)) {
+                        xfs_iext_direct_to_inline(ifp, new_size /
+                                (uint)sizeof(xfs_bmbt_rec_t));
+                        ifp->if_bytes = new_size;
+                        return;
+                }
+                if ((new_size & (new_size - 1)) != 0) {
+                        rnew_size = xfs_iroundup(new_size);
+                }
+                if (rnew_size != ifp->if_real_bytes) {
+                        ifp->if_u1.if_extents = (xfs_bmbt_rec_t *)
+                                kmem_realloc(ifp->if_u1.if_extents,
+                                                rnew_size,
+                                                ifp->if_real_bytes,
+                                                KM_SLEEP);
+                }
+                if (rnew_size > ifp->if_real_bytes) {
+                        memset(&ifp->if_u1.if_extents[ifp->if_bytes /
+                                (uint)sizeof(xfs_bmbt_rec_t)], 0,
+                                rnew_size - ifp->if_real_bytes);
+                }
+        }
+        /*
+         * Switch from the inline extent buffer to a direct
+         * extent list. Be sure to include the inline extent
+         * bytes in new_size.
+         */
+        else {
+                new_size += ifp->if_bytes;
+                if ((new_size & (new_size - 1)) != 0) {
+                        rnew_size = xfs_iroundup(new_size);
+                }
+                xfs_iext_inline_to_direct(ifp, rnew_size);
+        }
+        ifp->if_real_bytes = rnew_size;
+        ifp->if_bytes = new_size;
+}
+
+/*
+ * Switch from linear (direct) extent records to inline buffer.
+ */
+void
+xfs_iext_direct_to_inline(
+        xfs_ifork_t     *ifp,           /* inode fork pointer */
+        xfs_extnum_t    nextents)       /* number of extents in file */
+{
+        ASSERT(ifp->if_flags & XFS_IFEXTENTS);
+        ASSERT(nextents <= XFS_INLINE_EXTS);
+        /*
+         * The inline buffer was zeroed when we switched
+         * from inline to direct extent allocation mode,
+         * so we don't need to clear it here.
+         */
+        memcpy(ifp->if_u2.if_inline_ext, ifp->if_u1.if_extents,
+                nextents * sizeof(xfs_bmbt_rec_t));
+        kmem_free(ifp->if_u1.if_extents, KM_SLEEP);
+        ifp->if_u1.if_extents = ifp->if_u2.if_inline_ext;
+        ifp->if_real_bytes = 0;
+}
+
+/*
+ * Switch from inline buffer to linear (direct) extent records.
+ * new_size should already be rounded up to the next power of 2
+ * by the caller (when appropriate), so use new_size as it is.
+ * However, since new_size may be rounded up, we can't update
+ * if_bytes here. It is the caller's responsibility to update
+ * if_bytes upon return.
+ */
+void
+xfs_iext_inline_to_direct(
+        xfs_ifork_t     *ifp,           /* inode fork pointer */
+        int             new_size)       /* number of extents in file */
+{
+        ifp->if_u1.if_extents = (xfs_bmbt_rec_t *)
+                kmem_alloc(new_size, KM_SLEEP);
+        memset(ifp->if_u1.if_extents, 0, new_size);
+        if (ifp->if_bytes) {
+                memcpy(ifp->if_u1.if_extents, ifp->if_u2.if_inline_ext,
+                        ifp->if_bytes);
+                memset(ifp->if_u2.if_inline_ext, 0, XFS_INLINE_EXTS *
+                        sizeof(xfs_bmbt_rec_t));
+        }
+        ifp->if_real_bytes = new_size;
+}
+
+/*
+ * Free incore file extents.
+ */
+void
+xfs_iext_destroy(
+        xfs_ifork_t     *ifp)           /* inode fork pointer */
+{
+        if (ifp->if_real_bytes) {
+                kmem_free(ifp->if_u1.if_extents, ifp->if_real_bytes);
+        } else if (ifp->if_bytes) {
+                memset(ifp->if_u2.if_inline_ext, 0, XFS_INLINE_EXTS *
+                        sizeof(xfs_bmbt_rec_t));
+        }
+        ifp->if_u1.if_extents = NULL;
+        ifp->if_real_bytes = 0;
+        ifp->if_bytes = 0;
+}