+
+/*
+ * Splits an extent into two extents at split_fsb block such that it is
+ * the first block of the current_ext. @current_ext is a target extent
+ * to be split. @split_fsb is a block where the extents is split.
+ * If split_fsb lies in a hole or the first block of extents, just return 0.
+ */
+STATIC int
+xfs_bmap_split_extent_at(
+ struct xfs_trans *tp,
+ struct xfs_inode *ip,
+ xfs_fileoff_t split_fsb,
+ xfs_fsblock_t *firstfsb,
+ struct xfs_bmap_free *free_list)
+{
+ int whichfork = XFS_DATA_FORK;
+ struct xfs_btree_cur *cur = NULL;
+ struct xfs_bmbt_rec_host *gotp;
+ struct xfs_bmbt_irec got;
+ struct xfs_bmbt_irec new; /* split extent */
+ struct xfs_mount *mp = ip->i_mount;
+ struct xfs_ifork *ifp;
+ xfs_fsblock_t gotblkcnt; /* new block count for got */
+ xfs_extnum_t current_ext;
+ int error = 0;
+ int logflags = 0;
+ int i = 0;
+
+ if (unlikely(XFS_TEST_ERROR(
+ (XFS_IFORK_FORMAT(ip, whichfork) != XFS_DINODE_FMT_EXTENTS &&
+ XFS_IFORK_FORMAT(ip, whichfork) != XFS_DINODE_FMT_BTREE),
+ mp, XFS_ERRTAG_BMAPIFORMAT, XFS_RANDOM_BMAPIFORMAT))) {
+ XFS_ERROR_REPORT("xfs_bmap_split_extent_at",
+ XFS_ERRLEVEL_LOW, mp);
+ return -EFSCORRUPTED;
+ }
+
+ if (XFS_FORCED_SHUTDOWN(mp))
+ return -EIO;
+
+ ifp = XFS_IFORK_PTR(ip, whichfork);
+ if (!(ifp->if_flags & XFS_IFEXTENTS)) {
+ /* Read in all the extents */
+ error = xfs_iread_extents(tp, ip, whichfork);
+ if (error)
+ return error;
+ }
+
+ /*
+ * gotp can be null in 2 cases: 1) if there are no extents
+ * or 2) split_fsb lies in a hole beyond which there are
+ * no extents. Either way, we are done.
+ */
+ gotp = xfs_iext_bno_to_ext(ifp, split_fsb, ¤t_ext);
+ if (!gotp)
+ return 0;
+
+ xfs_bmbt_get_all(gotp, &got);
+
+ /*
+ * Check split_fsb lies in a hole or the start boundary offset
+ * of the extent.
+ */
+ if (got.br_startoff >= split_fsb)
+ return 0;
+
+ gotblkcnt = split_fsb - got.br_startoff;
+ new.br_startoff = split_fsb;
+ new.br_startblock = got.br_startblock + gotblkcnt;
+ new.br_blockcount = got.br_blockcount - gotblkcnt;
+ new.br_state = got.br_state;
+
+ if (ifp->if_flags & XFS_IFBROOT) {
+ cur = xfs_bmbt_init_cursor(mp, tp, ip, whichfork);
+ cur->bc_private.b.firstblock = *firstfsb;
+ cur->bc_private.b.flist = free_list;
+ cur->bc_private.b.flags = 0;
+ error = xfs_bmbt_lookup_eq(cur, got.br_startoff,
+ got.br_startblock,
+ got.br_blockcount,
+ &i);
+ if (error)
+ goto del_cursor;
+ XFS_WANT_CORRUPTED_GOTO(mp, i == 1, del_cursor);
+ }
+
+ xfs_bmbt_set_blockcount(gotp, gotblkcnt);
+ got.br_blockcount = gotblkcnt;
+
+ logflags = XFS_ILOG_CORE;
+ if (cur) {
+ error = xfs_bmbt_update(cur, got.br_startoff,
+ got.br_startblock,
+ got.br_blockcount,
+ got.br_state);
+ if (error)
+ goto del_cursor;
+ } else
+ logflags |= XFS_ILOG_DEXT;
+
+ /* Add new extent */
+ current_ext++;
+ xfs_iext_insert(ip, current_ext, 1, &new, 0);
+ XFS_IFORK_NEXT_SET(ip, whichfork,
+ XFS_IFORK_NEXTENTS(ip, whichfork) + 1);
+
+ if (cur) {
+ error = xfs_bmbt_lookup_eq(cur, new.br_startoff,
+ new.br_startblock, new.br_blockcount,
+ &i);
+ if (error)
+ goto del_cursor;
+ XFS_WANT_CORRUPTED_GOTO(mp, i == 0, del_cursor);
+ cur->bc_rec.b.br_state = new.br_state;
+
+ error = xfs_btree_insert(cur, &i);
+ if (error)
+ goto del_cursor;
+ XFS_WANT_CORRUPTED_GOTO(mp, i == 1, del_cursor);
+ }
+
+ /*
+ * Convert to a btree if necessary.
+ */
+ if (xfs_bmap_needs_btree(ip, whichfork)) {
+ int tmp_logflags; /* partial log flag return val */
+
+ ASSERT(cur == NULL);
+ error = xfs_bmap_extents_to_btree(tp, ip, firstfsb, free_list,
+ &cur, 0, &tmp_logflags, whichfork);
+ logflags |= tmp_logflags;
+ }
+
+del_cursor:
+ if (cur) {
+ cur->bc_private.b.allocated = 0;
+ xfs_btree_del_cursor(cur,
+ error ? XFS_BTREE_ERROR : XFS_BTREE_NOERROR);
+ }
+
+ if (logflags)
+ xfs_trans_log_inode(tp, ip, logflags);
+ return error;
+}
+
+int
+xfs_bmap_split_extent(
+ struct xfs_inode *ip,
+ xfs_fileoff_t split_fsb)
+{
+ struct xfs_mount *mp = ip->i_mount;
+ struct xfs_trans *tp;
+ struct xfs_bmap_free free_list;
+ xfs_fsblock_t firstfsb;
+ int committed;
+ int error;
+
+ tp = xfs_trans_alloc(mp, XFS_TRANS_DIOSTRAT);
+ error = xfs_trans_reserve(tp, &M_RES(mp)->tr_write,
+ XFS_DIOSTRAT_SPACE_RES(mp, 0), 0);
+ if (error) {
+ xfs_trans_cancel(tp, 0);
+ return error;
+ }
+
+ xfs_ilock(ip, XFS_ILOCK_EXCL);
+ xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
+
+ xfs_bmap_init(&free_list, &firstfsb);
+
+ error = xfs_bmap_split_extent_at(tp, ip, split_fsb,
+ &firstfsb, &free_list);
+ if (error)
+ goto out;
+
+ error = xfs_bmap_finish(&tp, &free_list, &committed);
+ if (error)
+ goto out;
+
+ return xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES);
+
+
+out:
+ xfs_trans_cancel(tp, XFS_TRANS_RELEASE_LOG_RES | XFS_TRANS_ABORT);
+ return error;
+}