Merge branch 'misc' of master.kernel.org:/pub/scm/linux/kernel/git/galak/powerpc...
[sfrench/cifs-2.6.git] / fs / xfs / xfs_inode.c
index 1d7f5a7e063eb3d34266919d538c3b1d53df41d7..94b60dd03801ba4ef4638ab0ffe50219a0170338 100644 (file)
@@ -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 */
 
 /*
@@ -159,7 +160,7 @@ xfs_inotobp(
        xfs_dinode_t    *dip;
 
        /*
-        * Call the space managment code to find the location of the
+        * Call the space management code to find the location of the
         * inode on disk.
         */
        imap.im_blkno = 0;
@@ -252,7 +253,8 @@ xfs_itobp(
        xfs_inode_t     *ip,
        xfs_dinode_t    **dipp,
        xfs_buf_t       **bpp,
-       xfs_daddr_t     bno)
+       xfs_daddr_t     bno,
+       uint            imap_flags)
 {
        xfs_buf_t       *bp;
        int             error;
@@ -268,10 +270,9 @@ xfs_itobp(
                 * inode on disk.
                 */
                imap.im_blkno = bno;
-               error = xfs_imap(mp, tp, ip->i_ino, &imap, XFS_IMAP_LOOKUP);
-               if (error != 0) {
+               if ((error = xfs_imap(mp, tp, ip->i_ino, &imap,
+                                       XFS_IMAP_LOOKUP | imap_flags)))
                        return error;
-               }
 
                /*
                 * If the inode number maps to a block outside the bounds
@@ -335,9 +336,10 @@ xfs_itobp(
         * (if DEBUG kernel) or the first inode in the buffer, otherwise.
         */
 #ifdef DEBUG
-       ni = BBTOB(imap.im_len) >> mp->m_sb.sb_inodelog;
+       ni = (imap_flags & XFS_IMAP_BULKSTAT) ? 0 :
+               (BBTOB(imap.im_len) >> mp->m_sb.sb_inodelog);
 #else
-       ni = 1;
+       ni = (imap_flags & XFS_IMAP_BULKSTAT) ? 0 : 1;
 #endif
        for (i = 0; i < ni; i++) {
                int             di_ok;
@@ -504,7 +506,7 @@ xfs_iformat(
        switch (INT_GET(dip->di_core.di_aformat, ARCH_CONVERT)) {
        case XFS_DINODE_FMT_LOCAL:
                atp = (xfs_attr_shortform_t *)XFS_DFORK_APTR(dip);
-               size = (int)INT_GET(atp->hdr.totsize, ARCH_CONVERT);
+               size = be16_to_cpu(atp->hdr.totsize);
                error = xfs_iformat_local(ip, dip, XFS_ATTR_FORK, size);
                break;
        case XFS_DINODE_FMT_EXTENTS:
@@ -597,7 +599,6 @@ xfs_iformat_extents(
        xfs_bmbt_rec_t  *ep, *dp;
        xfs_ifork_t     *ifp;
        int             nex;
-       int             real_size;
        int             size;
        int             i;
 
@@ -619,23 +620,20 @@ 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 +644,7 @@ 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);
@@ -839,7 +837,7 @@ xfs_dic2xflags(
 
 /*
  * Given a mount structure and an inode number, return a pointer
- * to a newly allocated in-core inode coresponding to the given
+ * to a newly allocated in-core inode corresponding to the given
  * inode number.
  *
  * Initialize the inode's attributes and extent pointers if it
@@ -871,9 +869,8 @@ xfs_iread(
         * return NULL as well.  Set i_blkno to 0 so that xfs_itobp() will
         * know that this is a new incore inode.
         */
-       error = xfs_itobp(mp, tp, ip, &dip, &bp, bno);
-
-       if (error != 0) {
+       error = xfs_itobp(mp, tp, ip, &dip, &bp, bno, 0);
+       if (error) {
                kmem_zone_free(xfs_inode_zone, ip);
                return error;
        }
@@ -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;
 }
 
@@ -1376,10 +1372,10 @@ xfs_itrunc_trace(
                     (void*)(unsigned long)((toss_finish >> 32) & 0xffffffff),
                     (void*)(unsigned long)(toss_finish & 0xffffffff),
                     (void*)(unsigned long)current_cpu(),
-                    (void*)0,
-                    (void*)0,
-                    (void*)0,
-                    (void*)0);
+                    (void*)(unsigned long)current_pid(),
+                    (void*)NULL,
+                    (void*)NULL,
+                    (void*)NULL);
 }
 #else
 #define        xfs_itrunc_trace(tag, ip, flag, new_size, toss_start, toss_finish)
@@ -1397,6 +1393,16 @@ xfs_itrunc_trace(
  * calling into the buffer/page cache code and we can't hold the
  * inode lock when we do so.
  *
+ * We need to wait for any direct I/Os in flight to complete before we
+ * proceed with the truncate. This is needed to prevent the extents
+ * being read or written by the direct I/Os from being removed while the
+ * I/O is in flight as there is no other method of synchronising
+ * direct I/O with the truncate operation.  Also, because we hold
+ * the IOLOCK in exclusive mode, we prevent new direct I/Os from being
+ * started until the truncate completes and drops the lock. Essentially,
+ * the vn_iowait() call forms an I/O barrier that provides strict ordering
+ * between direct I/Os and the truncate operation.
+ *
  * The flags parameter can have either the value XFS_ITRUNC_DEFINITE
  * or XFS_ITRUNC_MAYBE.  The XFS_ITRUNC_MAYBE value should be used
  * in the case that the caller is locking things out of order and
@@ -1424,6 +1430,9 @@ xfs_itruncate_start(
 
        mp = ip->i_mount;
        vp = XFS_ITOV(ip);
+
+       vn_iowait(vp);  /* wait for the completion of any pending DIOs */
+       
        /*
         * Call VOP_TOSS_PAGES() or VOP_FLUSHINVAL_PAGES() to get rid of pages and buffers
         * overlapping the region being removed.  We have to use
@@ -1899,7 +1908,7 @@ xfs_iunlink(
                 * Here we put the head pointer into our next pointer,
                 * and then we fall through to point the head at us.
                 */
-               error = xfs_itobp(mp, tp, ip, &dip, &ibp, 0);
+               error = xfs_itobp(mp, tp, ip, &dip, &ibp, 0, 0);
                if (error) {
                        return error;
                }
@@ -2008,7 +2017,7 @@ xfs_iunlink_remove(
                 * of dealing with the buffer when there is no need to
                 * change it.
                 */
-               error = xfs_itobp(mp, tp, ip, &dip, &ibp, 0);
+               error = xfs_itobp(mp, tp, ip, &dip, &ibp, 0, 0);
                if (error) {
                        cmn_err(CE_WARN,
                                "xfs_iunlink_remove: xfs_itobp()  returned an error %d on %s.  Returning error.",
@@ -2070,7 +2079,7 @@ xfs_iunlink_remove(
                 * Now last_ibp points to the buffer previous to us on
                 * the unlinked list.  Pull us from the list.
                 */
-               error = xfs_itobp(mp, tp, ip, &dip, &ibp, 0);
+               error = xfs_itobp(mp, tp, ip, &dip, &ibp, 0, 0);
                if (error) {
                        cmn_err(CE_WARN,
                                "xfs_iunlink_remove: xfs_itobp()  returned an error %d on %s.  Returning error.",
@@ -2475,92 +2484,6 @@ 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
@@ -2720,12 +2643,11 @@ xfs_idestroy_fork(
                        ifp->if_real_bytes = 0;
                }
        } else if ((ifp->if_flags & XFS_IFEXTENTS) &&
-                  (ifp->if_u1.if_extents != NULL) &&
-                  (ifp->if_u1.if_extents != ifp->if_u2.if_inline_ext)) {
+                  ((ifp->if_flags & XFS_IFEXTIREC) ||
+                   ((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);
@@ -2801,7 +2723,7 @@ xfs_ipin(
 /*
  * Decrement the pin count of the given inode, and wake up
  * anyone in xfs_iwait_unpin() if the count goes to 0.  The
- * inode must have been previoulsy pinned with a call to xfs_ipin().
+ * inode must have been previously pinned with a call to xfs_ipin().
  */
 void
 xfs_iunpin(
@@ -2810,16 +2732,29 @@ xfs_iunpin(
        ASSERT(atomic_read(&ip->i_pincount) > 0);
 
        if (atomic_dec_and_test(&ip->i_pincount)) {
-               vnode_t *vp = XFS_ITOV_NULL(ip);
+               /*
+                * If the inode is currently being reclaimed, the
+                * linux inode _and_ the xfs vnode may have been
+                * freed so we cannot reference either of them safely.
+                * Hence we should not try to do anything to them
+                * if the xfs inode is currently in the reclaim
+                * path.
+                *
+                * However, we still need to issue the unpin wakeup
+                * call as the inode reclaim may be blocked waiting for
+                * the inode to become unpinned.
+                */
+               if (!(ip->i_flags & (XFS_IRECLAIM|XFS_IRECLAIMABLE))) {
+                       vnode_t *vp = XFS_ITOV_NULL(ip);
 
-               /* make sync come back and flush this inode */
-               if (vp) {
-                       struct inode    *inode = LINVFS_GET_IP(vp);
+                       /* make sync come back and flush this inode */
+                       if (vp) {
+                               struct inode    *inode = vn_to_inode(vp);
 
-                       if (!(inode->i_state & I_NEW))
-                               mark_inode_dirty_sync(inode);
+                               if (!(inode->i_state & I_NEW))
+                                       mark_inode_dirty_sync(inode);
+                       }
                }
-
                wake_up(&ip->i_ipin_wait);
        }
 }
@@ -2902,16 +2837,15 @@ 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 +2855,10 @@ 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 +2928,10 @@ 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);
@@ -3114,8 +3049,8 @@ xfs_iflush(
        /*
         * Get the buffer containing the on-disk inode.
         */
-       error = xfs_itobp(mp, NULL, ip, &dip, &bp, 0);
-       if (error != 0) {
+       error = xfs_itobp(mp, NULL, ip, &dip, &bp, 0, 0);
+       if (error) {
                xfs_ifunlock(ip);
                return error;
        }
@@ -3610,7 +3545,7 @@ xfs_iaccess(
 {
        int             error;
        mode_t          orgmode = mode;
-       struct inode    *inode = LINVFS_GET_IP(XFS_ITOV(ip));
+       struct inode    *inode = vn_to_inode(XFS_ITOV(ip));
 
        if (mode & S_IWUSR) {
                umode_t         imode = inode->i_mode;
@@ -3704,3 +3639,1100 @@ 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_flags & XFS_IFEXTIREC) && (idx == 0)) {
+               return ifp->if_u1.if_ext_irec->er_extbuf;
+       } else if (ifp->if_flags & XFS_IFEXTIREC) {
+               xfs_ext_irec_t  *erp;           /* irec pointer */
+               int             erp_idx = 0;    /* irec index */
+               xfs_extnum_t    page_idx = idx; /* ext index in target list */
+
+               erp = xfs_iext_idx_to_irec(ifp, &page_idx, &erp_idx, 0);
+               return &erp->er_extbuf[page_idx];
+       } else 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)       /* number 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;
+               ifp->if_lastex = nextents + ext_diff;
+       }
+       /*
+        * 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 if (nextents + ext_diff <= XFS_LINEAR_EXTS) {
+               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);
+               }
+       }
+       /* Indirection array */
+       else {
+               xfs_ext_irec_t  *erp;
+               int             erp_idx = 0;
+               int             page_idx = idx;
+
+               ASSERT(nextents + ext_diff > XFS_LINEAR_EXTS);
+               if (ifp->if_flags & XFS_IFEXTIREC) {
+                       erp = xfs_iext_idx_to_irec(ifp, &page_idx, &erp_idx, 1);
+               } else {
+                       xfs_iext_irec_init(ifp);
+                       ASSERT(ifp->if_flags & XFS_IFEXTIREC);
+                       erp = ifp->if_u1.if_ext_irec;
+               }
+               /* Extents fit in target extent page */
+               if (erp && erp->er_extcount + ext_diff <= XFS_LINEAR_EXTS) {
+                       if (page_idx < erp->er_extcount) {
+                               memmove(&erp->er_extbuf[page_idx + ext_diff],
+                                       &erp->er_extbuf[page_idx],
+                                       (erp->er_extcount - page_idx) *
+                                       sizeof(xfs_bmbt_rec_t));
+                               memset(&erp->er_extbuf[page_idx], 0, byte_diff);
+                       }
+                       erp->er_extcount += ext_diff;
+                       xfs_iext_irec_update_extoffs(ifp, erp_idx + 1, ext_diff);
+               }
+               /* Insert a new extent page */
+               else if (erp) {
+                       xfs_iext_add_indirect_multi(ifp,
+                               erp_idx, page_idx, ext_diff);
+               }
+               /*
+                * If extent(s) are being appended to the last page in
+                * the indirection array and the new extent(s) don't fit
+                * in the page, then erp is NULL and erp_idx is set to
+                * the next index needed in the indirection array.
+                */
+               else {
+                       int     count = ext_diff;
+
+                       while (count) {
+                               erp = xfs_iext_irec_new(ifp, erp_idx);
+                               erp->er_extcount = count;
+                               count -= MIN(count, (int)XFS_LINEAR_EXTS);
+                               if (count) {
+                                       erp_idx++;
+                               }
+                       }
+               }
+       }
+       ifp->if_bytes = new_size;
+}
+
+/*
+ * This is called when incore extents are being added to the indirection
+ * array and the new extents do not fit in the target extent list. The
+ * erp_idx parameter contains the irec index for the target extent list
+ * in the indirection array, and the idx parameter contains the extent
+ * index within the list. The number of extents being added is stored
+ * in the count parameter.
+ *
+ *    |-------|   |-------|
+ *    |       |   |       |    idx - number of extents before idx
+ *    |  idx  |   | count |
+ *    |       |   |       |    count - number of extents being inserted at idx
+ *    |-------|   |-------|
+ *    | count |   | nex2  |    nex2 - number of extents after idx + count
+ *    |-------|   |-------|
+ */
+void
+xfs_iext_add_indirect_multi(
+       xfs_ifork_t     *ifp,                   /* inode fork pointer */
+       int             erp_idx,                /* target extent irec index */
+       xfs_extnum_t    idx,                    /* index within target list */
+       int             count)                  /* new extents being added */
+{
+       int             byte_diff;              /* new bytes being added */
+       xfs_ext_irec_t  *erp;                   /* pointer to irec entry */
+       xfs_extnum_t    ext_diff;               /* number of extents to add */
+       xfs_extnum_t    ext_cnt;                /* new extents still needed */
+       xfs_extnum_t    nex2;                   /* extents after idx + count */
+       xfs_bmbt_rec_t  *nex2_ep = NULL;        /* temp list for nex2 extents */
+       int             nlists;                 /* number of irec's (lists) */
+
+       ASSERT(ifp->if_flags & XFS_IFEXTIREC);
+       erp = &ifp->if_u1.if_ext_irec[erp_idx];
+       nex2 = erp->er_extcount - idx;
+       nlists = ifp->if_real_bytes / XFS_IEXT_BUFSZ;
+
+       /*
+        * Save second part of target extent list
+        * (all extents past */
+       if (nex2) {
+               byte_diff = nex2 * sizeof(xfs_bmbt_rec_t);
+               nex2_ep = (xfs_bmbt_rec_t *) kmem_alloc(byte_diff, KM_SLEEP);
+               memmove(nex2_ep, &erp->er_extbuf[idx], byte_diff);
+               erp->er_extcount -= nex2;
+               xfs_iext_irec_update_extoffs(ifp, erp_idx + 1, -nex2);
+               memset(&erp->er_extbuf[idx], 0, byte_diff);
+       }
+
+       /*
+        * Add the new extents to the end of the target
+        * list, then allocate new irec record(s) and
+        * extent buffer(s) as needed to store the rest
+        * of the new extents.
+        */
+       ext_cnt = count;
+       ext_diff = MIN(ext_cnt, (int)XFS_LINEAR_EXTS - erp->er_extcount);
+       if (ext_diff) {
+               erp->er_extcount += ext_diff;
+               xfs_iext_irec_update_extoffs(ifp, erp_idx + 1, ext_diff);
+               ext_cnt -= ext_diff;
+       }
+       while (ext_cnt) {
+               erp_idx++;
+               erp = xfs_iext_irec_new(ifp, erp_idx);
+               ext_diff = MIN(ext_cnt, (int)XFS_LINEAR_EXTS);
+               erp->er_extcount = ext_diff;
+               xfs_iext_irec_update_extoffs(ifp, erp_idx + 1, ext_diff);
+               ext_cnt -= ext_diff;
+       }
+
+       /* Add nex2 extents back to indirection array */
+       if (nex2) {
+               xfs_extnum_t    ext_avail;
+               int             i;
+
+               byte_diff = nex2 * sizeof(xfs_bmbt_rec_t);
+               ext_avail = XFS_LINEAR_EXTS - erp->er_extcount;
+               i = 0;
+               /*
+                * If nex2 extents fit in the current page, append
+                * nex2_ep after the new extents.
+                */
+               if (nex2 <= ext_avail) {
+                       i = erp->er_extcount;
+               }
+               /*
+                * Otherwise, check if space is available in the
+                * next page.
+                */
+               else if ((erp_idx < nlists - 1) &&
+                        (nex2 <= (ext_avail = XFS_LINEAR_EXTS -
+                         ifp->if_u1.if_ext_irec[erp_idx+1].er_extcount))) {
+                       erp_idx++;
+                       erp++;
+                       /* Create a hole for nex2 extents */
+                       memmove(&erp->er_extbuf[nex2], erp->er_extbuf,
+                               erp->er_extcount * sizeof(xfs_bmbt_rec_t));
+               }
+               /*
+                * Final choice, create a new extent page for
+                * nex2 extents.
+                */
+               else {
+                       erp_idx++;
+                       erp = xfs_iext_irec_new(ifp, erp_idx);
+               }
+               memmove(&erp->er_extbuf[i], nex2_ep, byte_diff);
+               kmem_free(nex2_ep, byte_diff);
+               erp->er_extcount += nex2;
+               xfs_iext_irec_update_extoffs(ifp, erp_idx + 1, nex2);
+       }
+}
+
+/*
+ * 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.
+ *
+ * If the amount of space needed has decreased below the linear
+ * limit, XFS_IEXT_BUFSZ, then switch to using the contiguous
+ * extent array.  Otherwise, use kmem_realloc() to adjust the
+ * size to what is needed.
+ */
+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_flags & XFS_IFEXTIREC) {
+               xfs_iext_remove_indirect(ifp, idx, ext_diff);
+       } 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(!(ifp->if_flags & XFS_IFEXTIREC));
+       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 */
+
+       ASSERT(!(ifp->if_flags & XFS_IFEXTIREC));
+       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;
+}
+
+/*
+ * This is called when incore extents are being removed from the
+ * indirection array and the extents being removed span multiple extent
+ * buffers. The idx parameter contains the file extent index where we
+ * want to begin removing extents, and the count parameter contains
+ * how many extents need to be removed.
+ *
+ *    |-------|   |-------|
+ *    | nex1  |   |       |    nex1 - number of extents before idx
+ *    |-------|   | count |
+ *    |       |   |       |    count - number of extents being removed at idx
+ *    | count |   |-------|
+ *    |       |   | nex2  |    nex2 - number of extents after idx + count
+ *    |-------|   |-------|
+ */
+void
+xfs_iext_remove_indirect(
+       xfs_ifork_t     *ifp,           /* inode fork pointer */
+       xfs_extnum_t    idx,            /* index to begin removing extents */
+       int             count)          /* number of extents to remove */
+{
+       xfs_ext_irec_t  *erp;           /* indirection array pointer */
+       int             erp_idx = 0;    /* indirection array index */
+       xfs_extnum_t    ext_cnt;        /* extents left to remove */
+       xfs_extnum_t    ext_diff;       /* extents to remove in current list */
+       xfs_extnum_t    nex1;           /* number of extents before idx */
+       xfs_extnum_t    nex2;           /* extents after idx + count */
+       int             nlists;         /* entries in indirection array */
+       int             page_idx = idx; /* index in target extent list */
+
+       ASSERT(ifp->if_flags & XFS_IFEXTIREC);
+       erp = xfs_iext_idx_to_irec(ifp,  &page_idx, &erp_idx, 0);
+       ASSERT(erp != NULL);
+       nlists = ifp->if_real_bytes / XFS_IEXT_BUFSZ;
+       nex1 = page_idx;
+       ext_cnt = count;
+       while (ext_cnt) {
+               nex2 = MAX((erp->er_extcount - (nex1 + ext_cnt)), 0);
+               ext_diff = MIN(ext_cnt, (erp->er_extcount - nex1));
+               /*
+                * Check for deletion of entire list;
+                * xfs_iext_irec_remove() updates extent offsets.
+                */
+               if (ext_diff == erp->er_extcount) {
+                       xfs_iext_irec_remove(ifp, erp_idx);
+                       ext_cnt -= ext_diff;
+                       nex1 = 0;
+                       if (ext_cnt) {
+                               ASSERT(erp_idx < ifp->if_real_bytes /
+                                       XFS_IEXT_BUFSZ);
+                               erp = &ifp->if_u1.if_ext_irec[erp_idx];
+                               nex1 = 0;
+                               continue;
+                       } else {
+                               break;
+                       }
+               }
+               /* Move extents up (if needed) */
+               if (nex2) {
+                       memmove(&erp->er_extbuf[nex1],
+                               &erp->er_extbuf[nex1 + ext_diff],
+                               nex2 * sizeof(xfs_bmbt_rec_t));
+               }
+               /* Zero out rest of page */
+               memset(&erp->er_extbuf[nex1 + nex2], 0, (XFS_IEXT_BUFSZ -
+                       ((nex1 + nex2) * sizeof(xfs_bmbt_rec_t))));
+               /* Update remaining counters */
+               erp->er_extcount -= ext_diff;
+               xfs_iext_irec_update_extoffs(ifp, erp_idx + 1, -ext_diff);
+               ext_cnt -= ext_diff;
+               nex1 = 0;
+               erp_idx++;
+               erp++;
+       }
+       ifp->if_bytes -= count * sizeof(xfs_bmbt_rec_t);
+       xfs_iext_irec_compact(ifp);
+}
+
+/*
+ * 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;
+
+       ASSERT(!(ifp->if_flags & XFS_IFEXTIREC) ||
+               ((new_size >= 0) && (new_size <= XFS_IEXT_BUFSZ) &&
+                (new_size != ifp->if_real_bytes)));
+
+       /* 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;
+}
+
+/*
+ * Resize an extent indirection array to new_size bytes.
+ */
+void
+xfs_iext_realloc_indirect(
+       xfs_ifork_t     *ifp,           /* inode fork pointer */
+       int             new_size)       /* new indirection array size */
+{
+       int             nlists;         /* number of irec's (ex lists) */
+       int             size;           /* current indirection array size */
+
+       ASSERT(ifp->if_flags & XFS_IFEXTIREC);
+       nlists = ifp->if_real_bytes / XFS_IEXT_BUFSZ;
+       size = nlists * sizeof(xfs_ext_irec_t);
+       ASSERT(ifp->if_real_bytes);
+       ASSERT((new_size >= 0) && (new_size != size));
+       if (new_size == 0) {
+               xfs_iext_destroy(ifp);
+       } else {
+               ifp->if_u1.if_ext_irec = (xfs_ext_irec_t *)
+                       kmem_realloc(ifp->if_u1.if_ext_irec,
+                               new_size, size, KM_SLEEP);
+       }
+}
+
+/*
+ * Switch from indirection array to linear (direct) extent allocations.
+ */
+void
+xfs_iext_indirect_to_direct(
+        xfs_ifork_t    *ifp)           /* inode fork pointer */
+{
+       xfs_bmbt_rec_t  *ep;            /* extent record pointer */
+       xfs_extnum_t    nextents;       /* number of extents in file */
+       int             size;           /* size of file extents */
+
+       ASSERT(ifp->if_flags & XFS_IFEXTIREC);
+       nextents = ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t);
+       ASSERT(nextents <= XFS_LINEAR_EXTS);
+       size = nextents * sizeof(xfs_bmbt_rec_t);
+
+       xfs_iext_irec_compact_full(ifp);
+       ASSERT(ifp->if_real_bytes == XFS_IEXT_BUFSZ);
+
+       ep = ifp->if_u1.if_ext_irec->er_extbuf;
+       kmem_free(ifp->if_u1.if_ext_irec, sizeof(xfs_ext_irec_t));
+       ifp->if_flags &= ~XFS_IFEXTIREC;
+       ifp->if_u1.if_extents = ep;
+       ifp->if_bytes = size;
+       if (nextents < XFS_LINEAR_EXTS) {
+               xfs_iext_realloc_direct(ifp, size);
+       }
+}
+
+/*
+ * Free incore file extents.
+ */
+void
+xfs_iext_destroy(
+       xfs_ifork_t     *ifp)           /* inode fork pointer */
+{
+       if (ifp->if_flags & XFS_IFEXTIREC) {
+               int     erp_idx;
+               int     nlists;
+
+               nlists = ifp->if_real_bytes / XFS_IEXT_BUFSZ;
+               for (erp_idx = nlists - 1; erp_idx >= 0 ; erp_idx--) {
+                       xfs_iext_irec_remove(ifp, erp_idx);
+               }
+               ifp->if_flags &= ~XFS_IFEXTIREC;
+       } else 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;
+}
+
+/*
+ * Return a pointer to the extent record for file system block bno.
+ */
+xfs_bmbt_rec_t *                       /* pointer to found extent record */
+xfs_iext_bno_to_ext(
+       xfs_ifork_t     *ifp,           /* inode fork pointer */
+       xfs_fileoff_t   bno,            /* block number to search for */
+       xfs_extnum_t    *idxp)          /* index of target extent */
+{
+       xfs_bmbt_rec_t  *base;          /* pointer to first extent */
+       xfs_filblks_t   blockcount = 0; /* number of blocks in extent */
+       xfs_bmbt_rec_t  *ep = NULL;     /* pointer to target extent */
+       xfs_ext_irec_t  *erp = NULL;    /* indirection array pointer */
+       int             high;           /* upper boundary in search */
+       xfs_extnum_t    idx = 0;        /* index of target extent */
+       int             low;            /* lower boundary in search */
+       xfs_extnum_t    nextents;       /* number of file extents */
+       xfs_fileoff_t   startoff = 0;   /* start offset of extent */
+
+       nextents = ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t);
+       if (nextents == 0) {
+               *idxp = 0;
+               return NULL;
+       }
+       low = 0;
+       if (ifp->if_flags & XFS_IFEXTIREC) {
+               /* Find target extent list */
+               int     erp_idx = 0;
+               erp = xfs_iext_bno_to_irec(ifp, bno, &erp_idx);
+               base = erp->er_extbuf;
+               high = erp->er_extcount - 1;
+       } else {
+               base = ifp->if_u1.if_extents;
+               high = nextents - 1;
+       }
+       /* Binary search extent records */
+       while (low <= high) {
+               idx = (low + high) >> 1;
+               ep = base + idx;
+               startoff = xfs_bmbt_get_startoff(ep);
+               blockcount = xfs_bmbt_get_blockcount(ep);
+               if (bno < startoff) {
+                       high = idx - 1;
+               } else if (bno >= startoff + blockcount) {
+                       low = idx + 1;
+               } else {
+                       /* Convert back to file-based extent index */
+                       if (ifp->if_flags & XFS_IFEXTIREC) {
+                               idx += erp->er_extoff;
+                       }
+                       *idxp = idx;
+                       return ep;
+               }
+       }
+       /* Convert back to file-based extent index */
+       if (ifp->if_flags & XFS_IFEXTIREC) {
+               idx += erp->er_extoff;
+       }
+       if (bno >= startoff + blockcount) {
+               if (++idx == nextents) {
+                       ep = NULL;
+               } else {
+                       ep = xfs_iext_get_ext(ifp, idx);
+               }
+       }
+       *idxp = idx;
+       return ep;
+}
+
+/*
+ * Return a pointer to the indirection array entry containing the
+ * extent record for filesystem block bno. Store the index of the
+ * target irec in *erp_idxp.
+ */
+xfs_ext_irec_t *                       /* pointer to found extent record */
+xfs_iext_bno_to_irec(
+       xfs_ifork_t     *ifp,           /* inode fork pointer */
+       xfs_fileoff_t   bno,            /* block number to search for */
+       int             *erp_idxp)      /* irec index of target ext list */
+{
+       xfs_ext_irec_t  *erp = NULL;    /* indirection array pointer */
+       xfs_ext_irec_t  *erp_next;      /* next indirection array entry */
+       int             erp_idx;        /* indirection array index */
+       int             nlists;         /* number of extent irec's (lists) */
+       int             high;           /* binary search upper limit */
+       int             low;            /* binary search lower limit */
+
+       ASSERT(ifp->if_flags & XFS_IFEXTIREC);
+       nlists = ifp->if_real_bytes / XFS_IEXT_BUFSZ;
+       erp_idx = 0;
+       low = 0;
+       high = nlists - 1;
+       while (low <= high) {
+               erp_idx = (low + high) >> 1;
+               erp = &ifp->if_u1.if_ext_irec[erp_idx];
+               erp_next = erp_idx < nlists - 1 ? erp + 1 : NULL;
+               if (bno < xfs_bmbt_get_startoff(erp->er_extbuf)) {
+                       high = erp_idx - 1;
+               } else if (erp_next && bno >=
+                          xfs_bmbt_get_startoff(erp_next->er_extbuf)) {
+                       low = erp_idx + 1;
+               } else {
+                       break;
+               }
+       }
+       *erp_idxp = erp_idx;
+       return erp;
+}
+
+/*
+ * Return a pointer to the indirection array entry containing the
+ * extent record at file extent index *idxp. Store the index of the
+ * target irec in *erp_idxp and store the page index of the target
+ * extent record in *idxp.
+ */
+xfs_ext_irec_t *
+xfs_iext_idx_to_irec(
+       xfs_ifork_t     *ifp,           /* inode fork pointer */
+       xfs_extnum_t    *idxp,          /* extent index (file -> page) */
+       int             *erp_idxp,      /* pointer to target irec */
+       int             realloc)        /* new bytes were just added */
+{
+       xfs_ext_irec_t  *prev;          /* pointer to previous irec */
+       xfs_ext_irec_t  *erp = NULL;    /* pointer to current irec */
+       int             erp_idx;        /* indirection array index */
+       int             nlists;         /* number of irec's (ex lists) */
+       int             high;           /* binary search upper limit */
+       int             low;            /* binary search lower limit */
+       xfs_extnum_t    page_idx = *idxp; /* extent index in target list */
+
+       ASSERT(ifp->if_flags & XFS_IFEXTIREC);
+       ASSERT(page_idx >= 0 && page_idx <=
+               ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t));
+       nlists = ifp->if_real_bytes / XFS_IEXT_BUFSZ;
+       erp_idx = 0;
+       low = 0;
+       high = nlists - 1;
+
+       /* Binary search extent irec's */
+       while (low <= high) {
+               erp_idx = (low + high) >> 1;
+               erp = &ifp->if_u1.if_ext_irec[erp_idx];
+               prev = erp_idx > 0 ? erp - 1 : NULL;
+               if (page_idx < erp->er_extoff || (page_idx == erp->er_extoff &&
+                    realloc && prev && prev->er_extcount < XFS_LINEAR_EXTS)) {
+                       high = erp_idx - 1;
+               } else if (page_idx > erp->er_extoff + erp->er_extcount ||
+                          (page_idx == erp->er_extoff + erp->er_extcount &&
+                           !realloc)) {
+                       low = erp_idx + 1;
+               } else if (page_idx == erp->er_extoff + erp->er_extcount &&
+                          erp->er_extcount == XFS_LINEAR_EXTS) {
+                       ASSERT(realloc);
+                       page_idx = 0;
+                       erp_idx++;
+                       erp = erp_idx < nlists ? erp + 1 : NULL;
+                       break;
+               } else {
+                       page_idx -= erp->er_extoff;
+                       break;
+               }
+       }
+       *idxp = page_idx;
+       *erp_idxp = erp_idx;
+       return(erp);
+}
+
+/*
+ * Allocate and initialize an indirection array once the space needed
+ * for incore extents increases above XFS_IEXT_BUFSZ.
+ */
+void
+xfs_iext_irec_init(
+       xfs_ifork_t     *ifp)           /* inode fork pointer */
+{
+       xfs_ext_irec_t  *erp;           /* indirection array pointer */
+       xfs_extnum_t    nextents;       /* number of extents in file */
+
+       ASSERT(!(ifp->if_flags & XFS_IFEXTIREC));
+       nextents = ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t);
+       ASSERT(nextents <= XFS_LINEAR_EXTS);
+
+       erp = (xfs_ext_irec_t *)
+               kmem_alloc(sizeof(xfs_ext_irec_t), KM_SLEEP);
+
+       if (nextents == 0) {
+               ifp->if_u1.if_extents = (xfs_bmbt_rec_t *)
+                       kmem_alloc(XFS_IEXT_BUFSZ, KM_SLEEP);
+       } else if (!ifp->if_real_bytes) {
+               xfs_iext_inline_to_direct(ifp, XFS_IEXT_BUFSZ);
+       } else if (ifp->if_real_bytes < XFS_IEXT_BUFSZ) {
+               xfs_iext_realloc_direct(ifp, XFS_IEXT_BUFSZ);
+       }
+       erp->er_extbuf = ifp->if_u1.if_extents;
+       erp->er_extcount = nextents;
+       erp->er_extoff = 0;
+
+       ifp->if_flags |= XFS_IFEXTIREC;
+       ifp->if_real_bytes = XFS_IEXT_BUFSZ;
+       ifp->if_bytes = nextents * sizeof(xfs_bmbt_rec_t);
+       ifp->if_u1.if_ext_irec = erp;
+
+       return;
+}
+
+/*
+ * Allocate and initialize a new entry in the indirection array.
+ */
+xfs_ext_irec_t *
+xfs_iext_irec_new(
+       xfs_ifork_t     *ifp,           /* inode fork pointer */
+       int             erp_idx)        /* index for new irec */
+{
+       xfs_ext_irec_t  *erp;           /* indirection array pointer */
+       int             i;              /* loop counter */
+       int             nlists;         /* number of irec's (ex lists) */
+
+       ASSERT(ifp->if_flags & XFS_IFEXTIREC);
+       nlists = ifp->if_real_bytes / XFS_IEXT_BUFSZ;
+
+       /* Resize indirection array */
+       xfs_iext_realloc_indirect(ifp, ++nlists *
+                                 sizeof(xfs_ext_irec_t));
+       /*
+        * Move records down in the array so the
+        * new page can use erp_idx.
+        */
+       erp = ifp->if_u1.if_ext_irec;
+       for (i = nlists - 1; i > erp_idx; i--) {
+               memmove(&erp[i], &erp[i-1], sizeof(xfs_ext_irec_t));
+       }
+       ASSERT(i == erp_idx);
+
+       /* Initialize new extent record */
+       erp = ifp->if_u1.if_ext_irec;
+       erp[erp_idx].er_extbuf = (xfs_bmbt_rec_t *)
+               kmem_alloc(XFS_IEXT_BUFSZ, KM_SLEEP);
+       ifp->if_real_bytes = nlists * XFS_IEXT_BUFSZ;
+       memset(erp[erp_idx].er_extbuf, 0, XFS_IEXT_BUFSZ);
+       erp[erp_idx].er_extcount = 0;
+       erp[erp_idx].er_extoff = erp_idx > 0 ?
+               erp[erp_idx-1].er_extoff + erp[erp_idx-1].er_extcount : 0;
+       return (&erp[erp_idx]);
+}
+
+/*
+ * Remove a record from the indirection array.
+ */
+void
+xfs_iext_irec_remove(
+       xfs_ifork_t     *ifp,           /* inode fork pointer */
+       int             erp_idx)        /* irec index to remove */
+{
+       xfs_ext_irec_t  *erp;           /* indirection array pointer */
+       int             i;              /* loop counter */
+       int             nlists;         /* number of irec's (ex lists) */
+
+       ASSERT(ifp->if_flags & XFS_IFEXTIREC);
+       nlists = ifp->if_real_bytes / XFS_IEXT_BUFSZ;
+       erp = &ifp->if_u1.if_ext_irec[erp_idx];
+       if (erp->er_extbuf) {
+               xfs_iext_irec_update_extoffs(ifp, erp_idx + 1,
+                       -erp->er_extcount);
+               kmem_free(erp->er_extbuf, XFS_IEXT_BUFSZ);
+       }
+       /* Compact extent records */
+       erp = ifp->if_u1.if_ext_irec;
+       for (i = erp_idx; i < nlists - 1; i++) {
+               memmove(&erp[i], &erp[i+1], sizeof(xfs_ext_irec_t));
+       }
+       /*
+        * Manually free the last extent record from the indirection
+        * array.  A call to xfs_iext_realloc_indirect() with a size
+        * of zero would result in a call to xfs_iext_destroy() which
+        * would in turn call this function again, creating a nasty
+        * infinite loop.
+        */
+       if (--nlists) {
+               xfs_iext_realloc_indirect(ifp,
+                       nlists * sizeof(xfs_ext_irec_t));
+       } else {
+               kmem_free(ifp->if_u1.if_ext_irec,
+                       sizeof(xfs_ext_irec_t));
+       }
+       ifp->if_real_bytes = nlists * XFS_IEXT_BUFSZ;
+}
+
+/*
+ * This is called to clean up large amounts of unused memory allocated
+ * by the indirection array.  Before compacting anything though, verify
+ * that the indirection array is still needed and switch back to the
+ * linear extent list (or even the inline buffer) if possible.  The
+ * compaction policy is as follows:
+ *
+ *    Full Compaction: Extents fit into a single page (or inline buffer)
+ *    Full Compaction: Extents occupy less than 10% of allocated space
+ * Partial Compaction: Extents occupy > 10% and < 50% of allocated space
+ *      No Compaction: Extents occupy at least 50% of allocated space
+ */
+void
+xfs_iext_irec_compact(
+       xfs_ifork_t     *ifp)           /* inode fork pointer */
+{
+       xfs_extnum_t    nextents;       /* number of extents in file */
+       int             nlists;         /* number of irec's (ex lists) */
+
+       ASSERT(ifp->if_flags & XFS_IFEXTIREC);
+       nlists = ifp->if_real_bytes / XFS_IEXT_BUFSZ;
+       nextents = ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t);
+
+       if (nextents == 0) {
+               xfs_iext_destroy(ifp);
+       } else if (nextents <= XFS_INLINE_EXTS) {
+               xfs_iext_indirect_to_direct(ifp);
+               xfs_iext_direct_to_inline(ifp, nextents);
+       } else if (nextents <= XFS_LINEAR_EXTS) {
+               xfs_iext_indirect_to_direct(ifp);
+       } else if (nextents < (nlists * XFS_LINEAR_EXTS) >> 3) {
+               xfs_iext_irec_compact_full(ifp);
+       } else if (nextents < (nlists * XFS_LINEAR_EXTS) >> 1) {
+               xfs_iext_irec_compact_pages(ifp);
+       }
+}
+
+/*
+ * Combine extents from neighboring extent pages.
+ */
+void
+xfs_iext_irec_compact_pages(
+       xfs_ifork_t     *ifp)           /* inode fork pointer */
+{
+       xfs_ext_irec_t  *erp, *erp_next;/* pointers to irec entries */
+       int             erp_idx = 0;    /* indirection array index */
+       int             nlists;         /* number of irec's (ex lists) */
+
+       ASSERT(ifp->if_flags & XFS_IFEXTIREC);
+       nlists = ifp->if_real_bytes / XFS_IEXT_BUFSZ;
+       while (erp_idx < nlists - 1) {
+               erp = &ifp->if_u1.if_ext_irec[erp_idx];
+               erp_next = erp + 1;
+               if (erp_next->er_extcount <=
+                   (XFS_LINEAR_EXTS - erp->er_extcount)) {
+                       memmove(&erp->er_extbuf[erp->er_extcount],
+                               erp_next->er_extbuf, erp_next->er_extcount *
+                               sizeof(xfs_bmbt_rec_t));
+                       erp->er_extcount += erp_next->er_extcount;
+                       /*
+                        * Free page before removing extent record
+                        * so er_extoffs don't get modified in
+                        * xfs_iext_irec_remove.
+                        */
+                       kmem_free(erp_next->er_extbuf, XFS_IEXT_BUFSZ);
+                       erp_next->er_extbuf = NULL;
+                       xfs_iext_irec_remove(ifp, erp_idx + 1);
+                       nlists = ifp->if_real_bytes / XFS_IEXT_BUFSZ;
+               } else {
+                       erp_idx++;
+               }
+       }
+}
+
+/*
+ * Fully compact the extent records managed by the indirection array.
+ */
+void
+xfs_iext_irec_compact_full(
+       xfs_ifork_t     *ifp)                   /* inode fork pointer */
+{
+       xfs_bmbt_rec_t  *ep, *ep_next;          /* extent record pointers */
+       xfs_ext_irec_t  *erp, *erp_next;        /* extent irec pointers */
+       int             erp_idx = 0;            /* extent irec index */
+       int             ext_avail;              /* empty entries in ex list */
+       int             ext_diff;               /* number of exts to add */
+       int             nlists;                 /* number of irec's (ex lists) */
+
+       ASSERT(ifp->if_flags & XFS_IFEXTIREC);
+       nlists = ifp->if_real_bytes / XFS_IEXT_BUFSZ;
+       erp = ifp->if_u1.if_ext_irec;
+       ep = &erp->er_extbuf[erp->er_extcount];
+       erp_next = erp + 1;
+       ep_next = erp_next->er_extbuf;
+       while (erp_idx < nlists - 1) {
+               ext_avail = XFS_LINEAR_EXTS - erp->er_extcount;
+               ext_diff = MIN(ext_avail, erp_next->er_extcount);
+               memcpy(ep, ep_next, ext_diff * sizeof(xfs_bmbt_rec_t));
+               erp->er_extcount += ext_diff;
+               erp_next->er_extcount -= ext_diff;
+               /* Remove next page */
+               if (erp_next->er_extcount == 0) {
+                       /*
+                        * Free page before removing extent record
+                        * so er_extoffs don't get modified in
+                        * xfs_iext_irec_remove.
+                        */
+                       kmem_free(erp_next->er_extbuf,
+                               erp_next->er_extcount * sizeof(xfs_bmbt_rec_t));
+                       erp_next->er_extbuf = NULL;
+                       xfs_iext_irec_remove(ifp, erp_idx + 1);
+                       erp = &ifp->if_u1.if_ext_irec[erp_idx];
+                       nlists = ifp->if_real_bytes / XFS_IEXT_BUFSZ;
+               /* Update next page */
+               } else {
+                       /* Move rest of page up to become next new page */
+                       memmove(erp_next->er_extbuf, ep_next,
+                               erp_next->er_extcount * sizeof(xfs_bmbt_rec_t));
+                       ep_next = erp_next->er_extbuf;
+                       memset(&ep_next[erp_next->er_extcount], 0,
+                               (XFS_LINEAR_EXTS - erp_next->er_extcount) *
+                               sizeof(xfs_bmbt_rec_t));
+               }
+               if (erp->er_extcount == XFS_LINEAR_EXTS) {
+                       erp_idx++;
+                       if (erp_idx < nlists)
+                               erp = &ifp->if_u1.if_ext_irec[erp_idx];
+                       else
+                               break;
+               }
+               ep = &erp->er_extbuf[erp->er_extcount];
+               erp_next = erp + 1;
+               ep_next = erp_next->er_extbuf;
+       }
+}
+
+/*
+ * This is called to update the er_extoff field in the indirection
+ * array when extents have been added or removed from one of the
+ * extent lists. erp_idx contains the irec index to begin updating
+ * at and ext_diff contains the number of extents that were added
+ * or removed.
+ */
+void
+xfs_iext_irec_update_extoffs(
+       xfs_ifork_t     *ifp,           /* inode fork pointer */
+       int             erp_idx,        /* irec index to update */
+       int             ext_diff)       /* number of new extents */
+{
+       int             i;              /* loop counter */
+       int             nlists;         /* number of irec's (ex lists */
+
+       ASSERT(ifp->if_flags & XFS_IFEXTIREC);
+       nlists = ifp->if_real_bytes / XFS_IEXT_BUFSZ;
+       for (i = erp_idx; i < nlists; i++) {
+               ifp->if_u1.if_ext_irec[i].er_extoff += ext_diff;
+       }
+}