#include "xfs_trace.h"
-#ifdef DEBUG
-STATIC void
-xfs_bmap_check_leaf_extents(xfs_btree_cur_t *cur, xfs_inode_t *ip, int whichfork);
-#endif
-
kmem_zone_t *xfs_bmap_free_item_zone;
/*
* Prototypes for internal bmap routines.
*/
+#ifdef DEBUG
+STATIC void
+xfs_bmap_check_leaf_extents(
+ struct xfs_btree_cur *cur,
+ struct xfs_inode *ip,
+ int whichfork);
+#else
+#define xfs_bmap_check_leaf_extents(cur, ip, whichfork) do { } while (0)
+#endif
+
/*
* Called from xfs_bmap_add_attrfork to handle extents format files.
xfs_bmap_free_t *flist, /* blocks to free at commit */
int *flags); /* inode logging flags */
-/*
- * Called by xfs_bmap_add_extent to handle cases converting a delayed
- * allocation to a real allocation.
- */
-STATIC int /* error */
-xfs_bmap_add_extent_delay_real(
- struct xfs_trans *tp, /* transaction pointer */
- xfs_inode_t *ip, /* incore inode pointer */
- xfs_extnum_t *idx, /* extent number to update/insert */
- xfs_btree_cur_t **curp, /* if *curp is null, not a btree */
- xfs_bmbt_irec_t *new, /* new data to add to file extents */
- xfs_filblks_t *dnew, /* new delayed-alloc indirect blocks */
- xfs_fsblock_t *first, /* pointer to firstblock variable */
- xfs_bmap_free_t *flist, /* list of extents to be freed */
- int *logflagsp); /* inode logging flags */
-
-/*
- * Called by xfs_bmap_add_extent to handle cases converting a hole
- * to a real allocation.
- */
-STATIC int /* error */
-xfs_bmap_add_extent_hole_real(
- xfs_inode_t *ip, /* incore inode pointer */
- xfs_extnum_t *idx, /* extent number to update/insert */
- xfs_btree_cur_t *cur, /* if null, not a btree */
- xfs_bmbt_irec_t *new, /* new data to add to file extents */
- int *logflagsp, /* inode logging flags */
- int whichfork); /* data or attr fork */
-
-/*
- * Called by xfs_bmap_add_extent to handle cases converting an unwritten
- * allocation to a real allocation or vice versa.
- */
-STATIC int /* error */
-xfs_bmap_add_extent_unwritten_real(
- xfs_inode_t *ip, /* incore inode pointer */
- xfs_extnum_t *idx, /* extent number to update/insert */
- xfs_btree_cur_t **curp, /* if *curp is null, not a btree */
- xfs_bmbt_irec_t *new, /* new data to add to file extents */
- int *logflagsp); /* inode logging flags */
-
/*
* xfs_bmap_alloc is called by xfs_bmapi to allocate an extent for a file.
* It figures out where to ask the underlying allocator to put the new extent.
}
/*
- * Update file extent records and the btree after allocating space.
- */
-STATIC int /* error */
-xfs_bmap_add_extent(
- struct xfs_trans *tp, /* transaction pointer */
- xfs_inode_t *ip, /* incore inode pointer */
- xfs_extnum_t *idx, /* extent number to update/insert */
- xfs_btree_cur_t **curp, /* if *curp is null, not a btree */
- xfs_bmbt_irec_t *new, /* new data to add to file extents */
- xfs_fsblock_t *first, /* pointer to firstblock variable */
- xfs_bmap_free_t *flist, /* list of extents to be freed */
- int *logflagsp, /* inode logging flags */
- int whichfork) /* data or attr fork */
-{
- xfs_btree_cur_t *cur; /* btree cursor or null */
- xfs_filblks_t da_new; /* new count del alloc blocks used */
- xfs_filblks_t da_old; /* old count del alloc blocks used */
- int error; /* error return value */
- xfs_ifork_t *ifp; /* inode fork ptr */
- int logflags; /* returned value */
- xfs_extnum_t nextents; /* number of extents in file now */
-
- XFS_STATS_INC(xs_add_exlist);
-
- cur = *curp;
- ifp = XFS_IFORK_PTR(ip, whichfork);
- nextents = ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t);
- da_old = da_new = 0;
- error = 0;
-
- ASSERT(*idx >= 0);
- ASSERT(*idx <= nextents);
- ASSERT(!isnullstartblock(new->br_startblock));
-
- /*
- * Real allocation off the end of the file.
- */
- if (*idx == nextents) {
- if (cur)
- ASSERT((cur->bc_private.b.flags &
- XFS_BTCUR_BPRV_WASDEL) == 0);
- error = xfs_bmap_add_extent_hole_real(ip, idx, cur, new,
- &logflags, whichfork);
- } else {
- xfs_bmbt_irec_t prev; /* old extent at offset idx */
-
- /*
- * Get the record referred to by idx.
- */
- xfs_bmbt_get_all(xfs_iext_get_ext(ifp, *idx), &prev);
- /*
- * If it's a real allocation record, and the new allocation ends
- * after the start of the referred to record, then we're filling
- * in a delayed or unwritten allocation with a real one, or
- * converting real back to unwritten.
- */
- if (!isnullstartblock(new->br_startblock) &&
- new->br_startoff + new->br_blockcount > prev.br_startoff) {
- if (prev.br_state != XFS_EXT_UNWRITTEN &&
- isnullstartblock(prev.br_startblock)) {
- da_old = startblockval(prev.br_startblock);
- if (cur)
- ASSERT(cur->bc_private.b.flags &
- XFS_BTCUR_BPRV_WASDEL);
- error = xfs_bmap_add_extent_delay_real(tp, ip,
- idx, &cur, new, &da_new,
- first, flist, &logflags);
- } else {
- ASSERT(new->br_state == XFS_EXT_NORM ||
- new->br_state == XFS_EXT_UNWRITTEN);
-
- error = xfs_bmap_add_extent_unwritten_real(ip,
- idx, &cur, new, &logflags);
- if (error)
- goto done;
- }
- }
- /*
- * Otherwise we're filling in a hole with an allocation.
- */
- else {
- if (cur)
- ASSERT((cur->bc_private.b.flags &
- XFS_BTCUR_BPRV_WASDEL) == 0);
- error = xfs_bmap_add_extent_hole_real(ip, idx, cur,
- new, &logflags, whichfork);
- }
- }
-
- if (error)
- goto done;
- ASSERT(*curp == cur || *curp == NULL);
-
- /*
- * Convert to a btree if necessary.
- */
- if (XFS_IFORK_FORMAT(ip, whichfork) == XFS_DINODE_FMT_EXTENTS &&
- XFS_IFORK_NEXTENTS(ip, whichfork) > ifp->if_ext_max) {
- int tmp_logflags; /* partial log flag return val */
-
- ASSERT(cur == NULL);
- error = xfs_bmap_extents_to_btree(tp, ip, first,
- flist, &cur, da_old > 0, &tmp_logflags, whichfork);
- logflags |= tmp_logflags;
- if (error)
- goto done;
- }
- /*
- * Adjust for changes in reserved delayed indirect blocks.
- * Nothing to do for disk quotas here.
- */
- if (da_old || da_new) {
- xfs_filblks_t nblks;
-
- nblks = da_new;
- if (cur)
- nblks += cur->bc_private.b.allocated;
- ASSERT(nblks <= da_old);
- if (nblks < da_old)
- xfs_icsb_modify_counters(ip->i_mount, XFS_SBS_FDBLOCKS,
- (int64_t)(da_old - nblks), 0);
- }
- /*
- * Clear out the allocated field, done with it now in any case.
- */
- if (cur) {
- cur->bc_private.b.allocated = 0;
- *curp = cur;
- }
-done:
-#ifdef DEBUG
- if (!error)
- xfs_bmap_check_leaf_extents(*curp, ip, whichfork);
-#endif
- *logflagsp = logflags;
- return error;
-}
-
-/*
- * Called by xfs_bmap_add_extent to handle cases converting a delayed
- * allocation to a real allocation.
+ * Convert a delayed allocation to a real allocation.
*/
STATIC int /* error */
xfs_bmap_add_extent_delay_real(
xfs_extnum_t *idx, /* extent number to update/insert */
xfs_btree_cur_t **curp, /* if *curp is null, not a btree */
xfs_bmbt_irec_t *new, /* new data to add to file extents */
- xfs_filblks_t *dnew, /* new delayed-alloc indirect blocks */
xfs_fsblock_t *first, /* pointer to firstblock variable */
xfs_bmap_free_t *flist, /* list of extents to be freed */
int *logflagsp) /* inode logging flags */
/* left is 0, right is 1, prev is 2 */
int rval=0; /* return value (logging flags) */
int state = 0;/* state bits, accessed thru macros */
- xfs_filblks_t temp=0; /* value for dnew calculations */
- xfs_filblks_t temp2=0;/* value for dnew calculations */
+ xfs_filblks_t da_new; /* new count del alloc blocks used */
+ xfs_filblks_t da_old; /* old count del alloc blocks used */
+ xfs_filblks_t temp=0; /* value for da_new calculations */
+ xfs_filblks_t temp2=0;/* value for da_new calculations */
int tmp_rval; /* partial logging flags */
+ ifp = XFS_IFORK_PTR(ip, XFS_DATA_FORK);
+ cur = *curp;
+
+ ASSERT(*idx >= 0);
+ ASSERT(*idx <= ifp->if_bytes / sizeof(struct xfs_bmbt_rec));
+ ASSERT(!isnullstartblock(new->br_startblock));
+ ASSERT(!cur || (cur->bc_private.b.flags & XFS_BTCUR_BPRV_WASDEL));
+
+ XFS_STATS_INC(xs_add_exlist);
+
+ *logflagsp = 0;
+
#define LEFT r[0]
#define RIGHT r[1]
#define PREV r[2]
/*
* Set up a bunch of variables to make the tests simpler.
*/
- cur = *curp;
- ifp = XFS_IFORK_PTR(ip, XFS_DATA_FORK);
ep = xfs_iext_get_ext(ifp, *idx);
xfs_bmbt_get_all(ep, &PREV);
new_endoff = new->br_startoff + new->br_blockcount;
ASSERT(PREV.br_startoff <= new->br_startoff);
ASSERT(PREV.br_startoff + PREV.br_blockcount >= new_endoff);
+ da_old = startblockval(PREV.br_startblock);
+ da_new = 0;
+
/*
* Set flags determining what part of the previous delayed allocation
* extent is being replaced by a real allocation.
RIGHT.br_blockcount, LEFT.br_state)))
goto done;
}
- *dnew = 0;
break;
case BMAP_LEFT_FILLING | BMAP_RIGHT_FILLING | BMAP_LEFT_CONTIG:
PREV.br_blockcount, LEFT.br_state)))
goto done;
}
- *dnew = 0;
break;
case BMAP_LEFT_FILLING | BMAP_RIGHT_FILLING | BMAP_RIGHT_CONTIG:
RIGHT.br_blockcount, PREV.br_state)))
goto done;
}
-
- *dnew = 0;
break;
case BMAP_LEFT_FILLING | BMAP_RIGHT_FILLING:
goto done;
XFS_WANT_CORRUPTED_GOTO(i == 1, done);
}
-
- *dnew = 0;
break;
case BMAP_LEFT_FILLING | BMAP_LEFT_CONTIG:
LEFT.br_state)))
goto done;
}
- temp = XFS_FILBLKS_MIN(xfs_bmap_worst_indlen(ip, temp),
+ da_new = XFS_FILBLKS_MIN(xfs_bmap_worst_indlen(ip, temp),
startblockval(PREV.br_startblock));
- xfs_bmbt_set_startblock(ep, nullstartblock((int)temp));
+ xfs_bmbt_set_startblock(ep, nullstartblock(da_new));
trace_xfs_bmap_post_update(ip, *idx, state, _THIS_IP_);
--*idx;
- *dnew = temp;
break;
case BMAP_LEFT_FILLING:
if (error)
goto done;
}
- temp = XFS_FILBLKS_MIN(xfs_bmap_worst_indlen(ip, temp),
+ da_new = XFS_FILBLKS_MIN(xfs_bmap_worst_indlen(ip, temp),
startblockval(PREV.br_startblock) -
(cur ? cur->bc_private.b.allocated : 0));
ep = xfs_iext_get_ext(ifp, *idx + 1);
- xfs_bmbt_set_startblock(ep, nullstartblock((int)temp));
+ xfs_bmbt_set_startblock(ep, nullstartblock(da_new));
trace_xfs_bmap_post_update(ip, *idx + 1, state, _THIS_IP_);
-
- *dnew = temp;
break;
case BMAP_RIGHT_FILLING | BMAP_RIGHT_CONTIG:
goto done;
}
- temp = XFS_FILBLKS_MIN(xfs_bmap_worst_indlen(ip, temp),
+ da_new = XFS_FILBLKS_MIN(xfs_bmap_worst_indlen(ip, temp),
startblockval(PREV.br_startblock));
trace_xfs_bmap_pre_update(ip, *idx, state, _THIS_IP_);
- xfs_bmbt_set_startblock(ep, nullstartblock((int)temp));
+ xfs_bmbt_set_startblock(ep, nullstartblock(da_new));
trace_xfs_bmap_post_update(ip, *idx, state, _THIS_IP_);
++*idx;
- *dnew = temp;
break;
case BMAP_RIGHT_FILLING:
if (error)
goto done;
}
- temp = XFS_FILBLKS_MIN(xfs_bmap_worst_indlen(ip, temp),
+ da_new = XFS_FILBLKS_MIN(xfs_bmap_worst_indlen(ip, temp),
startblockval(PREV.br_startblock) -
(cur ? cur->bc_private.b.allocated : 0));
ep = xfs_iext_get_ext(ifp, *idx);
- xfs_bmbt_set_startblock(ep, nullstartblock((int)temp));
+ xfs_bmbt_set_startblock(ep, nullstartblock(da_new));
trace_xfs_bmap_post_update(ip, *idx, state, _THIS_IP_);
++*idx;
- *dnew = temp;
break;
case 0:
trace_xfs_bmap_post_update(ip, *idx + 2, state, _THIS_IP_);
++*idx;
- *dnew = temp + temp2;
+ da_new = temp + temp2;
break;
case BMAP_LEFT_FILLING | BMAP_LEFT_CONTIG | BMAP_RIGHT_CONTIG:
*/
ASSERT(0);
}
- *curp = cur;
+
+ /* convert to a btree if necessary */
+ if (XFS_IFORK_FORMAT(ip, XFS_DATA_FORK) == XFS_DINODE_FMT_EXTENTS &&
+ XFS_IFORK_NEXTENTS(ip, XFS_DATA_FORK) > ifp->if_ext_max) {
+ int tmp_logflags; /* partial log flag return val */
+
+ ASSERT(cur == NULL);
+ error = xfs_bmap_extents_to_btree(tp, ip, first, flist, &cur,
+ da_old > 0, &tmp_logflags, XFS_DATA_FORK);
+ *logflagsp |= tmp_logflags;
+ if (error)
+ goto done;
+ }
+
+ /* adjust for changes in reserved delayed indirect blocks */
+ if (da_old || da_new) {
+ temp = da_new;
+ if (cur)
+ temp += cur->bc_private.b.allocated;
+ ASSERT(temp <= da_old);
+ if (temp < da_old)
+ xfs_icsb_modify_counters(ip->i_mount, XFS_SBS_FDBLOCKS,
+ (int64_t)(da_old - temp), 0);
+ }
+
+ /* clear out the allocated field, done with it now in any case. */
+ if (cur) {
+ cur->bc_private.b.allocated = 0;
+ *curp = cur;
+ }
+ xfs_bmap_check_leaf_extents(cur, ip, XFS_DATA_FORK);
done:
- *logflagsp = rval;
+ *logflagsp |= rval;
return error;
#undef LEFT
#undef RIGHT
}
/*
- * Called by xfs_bmap_add_extent to handle cases converting an unwritten
- * allocation to a real allocation or vice versa.
+ * Convert an unwritten allocation to a real allocation or vice versa.
*/
STATIC int /* error */
xfs_bmap_add_extent_unwritten_real(
+ struct xfs_trans *tp,
xfs_inode_t *ip, /* incore inode pointer */
xfs_extnum_t *idx, /* extent number to update/insert */
xfs_btree_cur_t **curp, /* if *curp is null, not a btree */
xfs_bmbt_irec_t *new, /* new data to add to file extents */
+ xfs_fsblock_t *first, /* pointer to firstblock variable */
+ xfs_bmap_free_t *flist, /* list of extents to be freed */
int *logflagsp) /* inode logging flags */
{
xfs_btree_cur_t *cur; /* btree cursor */
int rval=0; /* return value (logging flags) */
int state = 0;/* state bits, accessed thru macros */
+ *logflagsp = 0;
+
+ cur = *curp;
+ ifp = XFS_IFORK_PTR(ip, XFS_DATA_FORK);
+
+ ASSERT(*idx >= 0);
+ ASSERT(*idx <= ifp->if_bytes / sizeof(struct xfs_bmbt_rec));
+ ASSERT(!isnullstartblock(new->br_startblock));
+
+ XFS_STATS_INC(xs_add_exlist);
+
#define LEFT r[0]
#define RIGHT r[1]
#define PREV r[2]
+
/*
* Set up a bunch of variables to make the tests simpler.
*/
error = 0;
- cur = *curp;
- ifp = XFS_IFORK_PTR(ip, XFS_DATA_FORK);
ep = xfs_iext_get_ext(ifp, *idx);
xfs_bmbt_get_all(ep, &PREV);
newext = new->br_state;
*/
ASSERT(0);
}
- *curp = cur;
+
+ /* convert to a btree if necessary */
+ if (XFS_IFORK_FORMAT(ip, XFS_DATA_FORK) == XFS_DINODE_FMT_EXTENTS &&
+ XFS_IFORK_NEXTENTS(ip, XFS_DATA_FORK) > ifp->if_ext_max) {
+ int tmp_logflags; /* partial log flag return val */
+
+ ASSERT(cur == NULL);
+ error = xfs_bmap_extents_to_btree(tp, ip, first, flist, &cur,
+ 0, &tmp_logflags, XFS_DATA_FORK);
+ *logflagsp |= tmp_logflags;
+ if (error)
+ goto done;
+ }
+
+ /* clear out the allocated field, done with it now in any case. */
+ if (cur) {
+ cur->bc_private.b.allocated = 0;
+ *curp = cur;
+ }
+
+ xfs_bmap_check_leaf_extents(*curp, ip, XFS_DATA_FORK);
done:
- *logflagsp = rval;
+ *logflagsp |= rval;
return error;
#undef LEFT
#undef RIGHT
}
/*
- * Called by xfs_bmap_add_extent to handle cases converting a hole
- * to a real allocation.
+ * Convert a hole to a real allocation.
*/
STATIC int /* error */
xfs_bmap_add_extent_hole_real(
+ struct xfs_trans *tp,
xfs_inode_t *ip, /* incore inode pointer */
xfs_extnum_t *idx, /* extent number to update/insert */
- xfs_btree_cur_t *cur, /* if null, not a btree */
+ xfs_btree_cur_t **curp, /* if null, not a btree */
xfs_bmbt_irec_t *new, /* new data to add to file extents */
+ xfs_fsblock_t *first, /* pointer to firstblock variable */
+ xfs_bmap_free_t *flist, /* list of extents to be freed */
int *logflagsp, /* inode logging flags */
int whichfork) /* data or attr fork */
{
int error; /* error return value */
int i; /* temp state */
+ xfs_btree_cur_t *cur; /* if null, not a btree */
xfs_ifork_t *ifp; /* inode fork pointer */
xfs_bmbt_irec_t left; /* left neighbor extent entry */
xfs_bmbt_irec_t right; /* right neighbor extent entry */
int rval=0; /* return value (logging flags) */
int state; /* state bits, accessed thru macros */
+ *logflagsp = 0;
+
ifp = XFS_IFORK_PTR(ip, whichfork);
- ASSERT(*idx <= ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t));
- state = 0;
+ cur = *curp;
+
+ ASSERT(*idx >= 0);
+ ASSERT(*idx <= ifp->if_bytes / sizeof(struct xfs_bmbt_rec));
+ ASSERT(!isnullstartblock(new->br_startblock));
+ ASSERT(!cur || !(cur->bc_private.b.flags & XFS_BTCUR_BPRV_WASDEL));
+
+ XFS_STATS_INC(xs_add_exlist);
+ state = 0;
if (whichfork == XFS_ATTR_FORK)
state |= BMAP_ATTRFORK;
}
break;
}
+
+ /* convert to a btree if necessary */
+ if (XFS_IFORK_FORMAT(ip, whichfork) == XFS_DINODE_FMT_EXTENTS &&
+ XFS_IFORK_NEXTENTS(ip, whichfork) > ifp->if_ext_max) {
+ int tmp_logflags; /* partial log flag return val */
+
+ ASSERT(cur == NULL);
+ error = xfs_bmap_extents_to_btree(tp, ip, first,
+ flist, &cur, 0, &tmp_logflags, whichfork);
+ *logflagsp |= tmp_logflags;
+ if (error)
+ goto done;
+ }
+
+ /* clear out the allocated field, done with it now in any case. */
+ if (cur) {
+ cur->bc_private.b.allocated = 0;
+ *curp = cur;
+ }
+ xfs_bmap_check_leaf_extents(cur, ip, whichfork);
done:
- *logflagsp = rval;
+ *logflagsp |= rval;
return error;
}
xfs_sb_version_hasextflgbit(&mp->m_sb))
bma->gotp->br_state = XFS_EXT_UNWRITTEN;
- error = xfs_bmap_add_extent(bma->tp, bma->ip, lastx, cur, bma->gotp,
- firstblock, flist, logflags, whichfork);
+ if (bma->wasdel) {
+ error = xfs_bmap_add_extent_delay_real(bma->tp, bma->ip, lastx,
+ cur, bma->gotp, firstblock, flist, logflags);
+ } else {
+ error = xfs_bmap_add_extent_hole_real(bma->tp, bma->ip, lastx,
+ cur, bma->gotp, firstblock, flist, logflags,
+ whichfork);
+ }
+
if (error)
return error;
/*
- * Update our extent pointer, given that xfs_bmap_add_extent might
- * have merged it into one of the neighbouring ones.
+ * Update our extent pointer, given that xfs_bmap_add_extent_delay_real
+ * or xfs_bmap_add_extent_hole_real might have merged it into one of
+ * the neighbouring ones.
*/
xfs_bmbt_get_all(xfs_iext_get_ext(ifp, *lastx), bma->gotp);
mval->br_state = (mval->br_state == XFS_EXT_UNWRITTEN)
? XFS_EXT_NORM : XFS_EXT_UNWRITTEN;
- error = xfs_bmap_add_extent(bma->tp, bma->ip, lastx, cur, mval,
- firstblock, flist, logflags, whichfork);
+ error = xfs_bmap_add_extent_unwritten_real(bma->tp, bma->ip, lastx,
+ cur, mval, firstblock, flist, logflags);
if (error)
return error;
/*
- * Update our extent pointer, given that xfs_bmap_add_extent might
- * have merged it into one of the neighbouring ones.
+ * Update our extent pointer, given that
+ * xfs_bmap_add_extent_unwritten_real might have merged it into one
+ * of the neighbouring ones.
*/
xfs_bmbt_get_all(xfs_iext_get_ext(ifp, *lastx), bma->gotp);
del.br_blockcount = mod;
}
del.br_state = XFS_EXT_UNWRITTEN;
- error = xfs_bmap_add_extent(tp, ip, &lastx, &cur, &del,
- firstblock, flist, &logflags,
- XFS_DATA_FORK);
+ error = xfs_bmap_add_extent_unwritten_real(tp, ip,
+ &lastx, &cur, &del, firstblock, flist,
+ &logflags);
if (error)
goto error0;
goto nodelete;
}
prev.br_state = XFS_EXT_UNWRITTEN;
lastx--;
- error = xfs_bmap_add_extent(tp, ip, &lastx,
- &cur, &prev, firstblock, flist,
- &logflags, XFS_DATA_FORK);
+ error = xfs_bmap_add_extent_unwritten_real(tp,
+ ip, &lastx, &cur, &prev,
+ firstblock, flist, &logflags);
if (error)
goto error0;
goto nodelete;
} else {
ASSERT(del.br_state == XFS_EXT_NORM);
del.br_state = XFS_EXT_UNWRITTEN;
- error = xfs_bmap_add_extent(tp, ip, &lastx,
- &cur, &del, firstblock, flist,
- &logflags, XFS_DATA_FORK);
+ error = xfs_bmap_add_extent_unwritten_real(tp,
+ ip, &lastx, &cur, &del,
+ firstblock, flist, &logflags);
if (error)
goto error0;
goto nodelete;
git.openpandora.org / pandora-kernel.git / commitdiff