Merge branch 'fallocate-insert-range' into for-next

fs/open.c

@@ -231,8 +231,7 @@ int vfs_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
 		return -EINVAL;
 
 	/* Return error if mode is not supported */
-	if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE |
-		     FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_ZERO_RANGE))
+	if (mode & ~FALLOC_FL_SUPPORTED_MASK)
 		return -EOPNOTSUPP;
 
 	/* Punch hole and zero range are mutually exclusive */
@@ -250,6 +249,11 @@ int vfs_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
 	    (mode & ~FALLOC_FL_COLLAPSE_RANGE))
 		return -EINVAL;
 
+	/* Insert range should only be used exclusively. */
+	if ((mode & FALLOC_FL_INSERT_RANGE) &&
+	    (mode & ~FALLOC_FL_INSERT_RANGE))
+		return -EINVAL;
+
 	if (!(file->f_mode & FMODE_WRITE))
 		return -EBADF;
 

fs/xfs/libxfs/xfs_bmap.c

@@ -5486,52 +5486,92 @@ xfs_bmse_shift_one(
 	int				*current_ext,
 	struct xfs_bmbt_rec_host	*gotp,
 	struct xfs_btree_cur		*cur,
-	int				*logflags)
+	int				*logflags,
+	enum shift_direction		direction)
 {
 	struct xfs_ifork		*ifp;
 	struct xfs_mount		*mp;
 	xfs_fileoff_t			startoff;
-	struct xfs_bmbt_rec_host	*leftp;
+	struct xfs_bmbt_rec_host	*adj_irecp;
 	struct xfs_bmbt_irec		got;
-	struct xfs_bmbt_irec		left;
+	struct xfs_bmbt_irec		adj_irec;
 	int				error;
 	int				i;
+	int				total_extents;
 
 	mp = ip->i_mount;
 	ifp = XFS_IFORK_PTR(ip, whichfork);
+	total_extents = ifp->if_bytes / sizeof(xfs_bmbt_rec_t);
 
 	xfs_bmbt_get_all(gotp, &got);
-	startoff = got.br_startoff - offset_shift_fsb;
 
 	/* delalloc extents should be prevented by caller */
 	XFS_WANT_CORRUPTED_RETURN(mp, !isnullstartblock(got.br_startblock));
 
-	/*
-	 * Check for merge if we've got an extent to the left, otherwise make
-	 * sure there's enough room at the start of the file for the shift.
-	 */
-	if (*current_ext) {
-		/* grab the left extent and check for a large enough hole */
-		leftp = xfs_iext_get_ext(ifp, *current_ext - 1);
-		xfs_bmbt_get_all(leftp, &left);
+	if (direction == SHIFT_LEFT) {
+		startoff = got.br_startoff - offset_shift_fsb;
+
+		/*
+		 * Check for merge if we've got an extent to the left,
+		 * otherwise make sure there's enough room at the start
+		 * of the file for the shift.
+		 */
+		if (!*current_ext) {
+			if (got.br_startoff < offset_shift_fsb)
+				return -EINVAL;
+			goto update_current_ext;
+		}
+		/*
+		 * grab the left extent and check for a large
+		 * enough hole.
+		 */
+		adj_irecp = xfs_iext_get_ext(ifp, *current_ext - 1);
+		xfs_bmbt_get_all(adj_irecp, &adj_irec);
 
-		if (startoff < left.br_startoff + left.br_blockcount)
+		if (startoff <
+		    adj_irec.br_startoff + adj_irec.br_blockcount)
 			return -EINVAL;
 
 		/* check whether to merge the extent or shift it down */
-		if (xfs_bmse_can_merge(&left, &got, offset_shift_fsb)) {
+		if (xfs_bmse_can_merge(&adj_irec, &got,
+				       offset_shift_fsb)) {
 			return xfs_bmse_merge(ip, whichfork, offset_shift_fsb,
-					      *current_ext, gotp, leftp, cur,
-					      logflags);
+					      *current_ext, gotp, adj_irecp,
+					      cur, logflags);
 		}
-	} else if (got.br_startoff < offset_shift_fsb)
-		return -EINVAL;
-
+	} else {
+		startoff = got.br_startoff + offset_shift_fsb;
+		/* nothing to move if this is the last extent */
+		if (*current_ext >= (total_extents - 1))
+			goto update_current_ext;
+		/*
+		 * If this is not the last extent in the file, make sure there
+		 * is enough room between current extent and next extent for
+		 * accommodating the shift.
+		 */
+		adj_irecp = xfs_iext_get_ext(ifp, *current_ext + 1);
+		xfs_bmbt_get_all(adj_irecp, &adj_irec);
+		if (startoff + got.br_blockcount > adj_irec.br_startoff)
+			return -EINVAL;
+		/*
+		 * Unlike a left shift (which involves a hole punch),
+		 * a right shift does not modify extent neighbors
+		 * in any way. We should never find mergeable extents
+		 * in this scenario. Check anyways and warn if we
+		 * encounter two extents that could be one.
+		 */
+		if (xfs_bmse_can_merge(&got, &adj_irec, offset_shift_fsb))
+			WARN_ON_ONCE(1);
+	}
 	/*
 	 * Increment the extent index for the next iteration, update the start
 	 * offset of the in-core extent and update the btree if applicable.
 	 */
-	(*current_ext)++;
+update_current_ext:
+	if (direction == SHIFT_LEFT)
+		(*current_ext)++;
+	else
+		(*current_ext)--;
 	xfs_bmbt_set_startoff(gotp, startoff);
 	*logflags |= XFS_ILOG_CORE;
 	if (!cur) {
@@ -5547,14 +5587,14 @@ xfs_bmse_shift_one(
 
 	got.br_startoff = startoff;
 	return xfs_bmbt_update(cur, got.br_startoff, got.br_startblock,
-				got.br_blockcount, got.br_state);
+			       got.br_blockcount, got.br_state);
 }
 
 /*
- * Shift extent records to the left to cover a hole.
+ * Shift extent records to the left/right to cover/create a hole.
  *
  * The maximum number of extents to be shifted in a single operation is
- * @num_exts. @start_fsb specifies the file offset to start the shift and the
+ * @num_exts. @stop_fsb specifies the file offset at which to stop shift and the
  * file offset where we've left off is returned in @next_fsb. @offset_shift_fsb
  * is the length by which each extent is shifted. If there is no hole to shift
  * the extents into, this will be considered invalid operation and we abort
@@ -5564,12 +5604,13 @@ int
 xfs_bmap_shift_extents(
 	struct xfs_trans	*tp,
 	struct xfs_inode	*ip,
-	xfs_fileoff_t		start_fsb,
+	xfs_fileoff_t		*next_fsb,
 	xfs_fileoff_t		offset_shift_fsb,
 	int			*done,
-	xfs_fileoff_t		*next_fsb,
+	xfs_fileoff_t		stop_fsb,
 	xfs_fsblock_t		*firstblock,
 	struct xfs_bmap_free	*flist,
+	enum shift_direction	direction,
 	int			num_exts)
 {
 	struct xfs_btree_cur		*cur = NULL;
@@ -5579,10 +5620,11 @@ xfs_bmap_shift_extents(
 	struct xfs_ifork		*ifp;
 	xfs_extnum_t			nexts = 0;
 	xfs_extnum_t			current_ext;
+	xfs_extnum_t			total_extents;
+	xfs_extnum_t			stop_extent;
 	int				error = 0;
 	int				whichfork = XFS_DATA_FORK;
 	int				logflags = 0;
-	int				total_extents;
 
 	if (unlikely(XFS_TEST_ERROR(
 	    (XFS_IFORK_FORMAT(ip, whichfork) != XFS_DINODE_FMT_EXTENTS &&
@@ -5598,6 +5640,8 @@ xfs_bmap_shift_extents(
 
 	ASSERT(xfs_isilocked(ip, XFS_IOLOCK_EXCL));
 	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
+	ASSERT(direction == SHIFT_LEFT || direction == SHIFT_RIGHT);
+	ASSERT(*next_fsb != NULLFSBLOCK || direction == SHIFT_RIGHT);
 
 	ifp = XFS_IFORK_PTR(ip, whichfork);
 	if (!(ifp->if_flags & XFS_IFEXTENTS)) {
@@ -5614,44 +5658,84 @@ xfs_bmap_shift_extents(
 		cur->bc_private.b.flags = 0;
 	}
 
+	/*
+	 * There may be delalloc extents in the data fork before the range we
+	 * are collapsing out, so we cannot use the count of real extents here.
+	 * Instead we have to calculate it from the incore fork.
+	 */
+	total_extents = ifp->if_bytes / sizeof(xfs_bmbt_rec_t);
+	if (total_extents == 0) {
+		*done = 1;
+		goto del_cursor;
+	}
+
+	/*
+	 * In case of first right shift, we need to initialize next_fsb
+	 */
+	if (*next_fsb == NULLFSBLOCK) {
+		gotp = xfs_iext_get_ext(ifp, total_extents - 1);
+		xfs_bmbt_get_all(gotp, &got);
+		*next_fsb = got.br_startoff;
+		if (stop_fsb > *next_fsb) {
+			*done = 1;
+			goto del_cursor;
+		}
+	}
+
+	/* Lookup the extent index at which we have to stop */
+	if (direction == SHIFT_RIGHT) {
+		gotp = xfs_iext_bno_to_ext(ifp, stop_fsb, &stop_extent);
+		/* Make stop_extent exclusive of shift range */
+		stop_extent--;
+	} else
+		stop_extent = total_extents;
+
 	/*
 	 * Look up the extent index for the fsb where we start shifting. We can
 	 * henceforth iterate with current_ext as extent list changes are locked
 	 * out via ilock.
 	 *
 	 * gotp can be null in 2 cases: 1) if there are no extents or 2)
-	 * start_fsb lies in a hole beyond which there are no extents. Either
+	 * *next_fsb lies in a hole beyond which there are no extents. Either
 	 * way, we are done.
 	 */
-	gotp = xfs_iext_bno_to_ext(ifp, start_fsb, &current_ext);
+	gotp = xfs_iext_bno_to_ext(ifp, *next_fsb, &current_ext);
 	if (!gotp) {
 		*done = 1;
 		goto del_cursor;
 	}
 
-	/*
-	 * There may be delalloc extents in the data fork before the range we
-	 * are collapsing out, so we cannot use the count of real extents here.
-	 * Instead we have to calculate it from the incore fork.
-	 */
-	total_extents = ifp->if_bytes / sizeof(xfs_bmbt_rec_t);
-	while (nexts++ < num_exts && current_ext < total_extents) {
+	/* some sanity checking before we finally start shifting extents */
+	if ((direction == SHIFT_LEFT && current_ext >= stop_extent) ||
+	     (direction == SHIFT_RIGHT && current_ext <= stop_extent)) {
+		error = -EIO;
+		goto del_cursor;
+	}
+
+	while (nexts++ < num_exts) {
 		error = xfs_bmse_shift_one(ip, whichfork, offset_shift_fsb,
-					&current_ext, gotp, cur, &logflags);
+					   &current_ext, gotp, cur, &logflags,
+					   direction);
 		if (error)
 			goto del_cursor;
+		/*
+		 * If there was an extent merge during the shift, the extent
+		 * count can change. Update the total and grade the next record.
+		 */
+		if (direction == SHIFT_LEFT) {
+			total_extents = ifp->if_bytes / sizeof(xfs_bmbt_rec_t);
+			stop_extent = total_extents;
+		}
 
-		/* update total extent count and grab the next record */
-		total_extents = ifp->if_bytes / sizeof(xfs_bmbt_rec_t);
-		if (current_ext >= total_extents)
+		if (current_ext == stop_extent) {
+			*done = 1;
+			*next_fsb = NULLFSBLOCK;
 			break;
+		}
 		gotp = xfs_iext_get_ext(ifp, current_ext);
 	}
 
-	/* Check if we are done */
-	if (current_ext == total_extents) {
-		*done = 1;
-	} else if (next_fsb) {
+	if (!*done) {
 		xfs_bmbt_get_all(gotp, &got);
 		*next_fsb = got.br_startoff;
 	}
@@ -5666,3 +5750,189 @@ xfs_bmap_shift_extents(
 
 	return error;
 }
+
+/*
+ * 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, &current_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;
+}

fs/xfs/libxfs/xfs_bmap.h

@@ -166,6 +166,11 @@ static inline void xfs_bmap_init(xfs_bmap_free_t *flp, xfs_fsblock_t *fbp)
  */
 #define XFS_BMAP_MAX_SHIFT_EXTENTS	1
 
+enum shift_direction {
+	SHIFT_LEFT = 0,
+	SHIFT_RIGHT,
+};
+
 #ifdef DEBUG
 void	xfs_bmap_trace_exlist(struct xfs_inode *ip, xfs_extnum_t cnt,
 		int whichfork, unsigned long caller_ip);
@@ -211,8 +216,10 @@ int	xfs_check_nostate_extents(struct xfs_ifork *ifp, xfs_extnum_t idx,
 		xfs_extnum_t num);
 uint	xfs_default_attroffset(struct xfs_inode *ip);
 int	xfs_bmap_shift_extents(struct xfs_trans *tp, struct xfs_inode *ip,
-		xfs_fileoff_t start_fsb, xfs_fileoff_t offset_shift_fsb,
-		int *done, xfs_fileoff_t *next_fsb, xfs_fsblock_t *firstblock,
-		struct xfs_bmap_free *flist, int num_exts);
+		xfs_fileoff_t *next_fsb, xfs_fileoff_t offset_shift_fsb,
+		int *done, xfs_fileoff_t stop_fsb, xfs_fsblock_t *firstblock,
+		struct xfs_bmap_free *flist, enum shift_direction direction,
+		int num_exts);
+int	xfs_bmap_split_extent(struct xfs_inode *ip, xfs_fileoff_t split_offset);
 
 #endif	/* __XFS_BMAP_H__ */

fs/xfs/xfs_bmap_util.c

@@ -1376,22 +1376,19 @@ xfs_zero_file_space(
 }
 
 /*
- * xfs_collapse_file_space()
- *	This routine frees disk space and shift extent for the given file.
- *	The first thing we do is to free data blocks in the specified range
- *	by calling xfs_free_file_space(). It would also sync dirty data
- *	and invalidate page cache over the region on which collapse range
- *	is working. And Shift extent records to the left to cover a hole.
- * RETURNS:
- *	0 on success
- *	errno on error
- *
+ * @next_fsb will keep track of the extent currently undergoing shift.
+ * @stop_fsb will keep track of the extent at which we have to stop.
+ * If we are shifting left, we will start with block (offset + len) and
+ * shift each extent till last extent.
+ * If we are shifting right, we will start with last extent inside file space
+ * and continue until we reach the block corresponding to offset.
  */
 int
-xfs_collapse_file_space(
-	struct xfs_inode	*ip,
-	xfs_off_t		offset,
-	xfs_off_t		len)
+xfs_shift_file_space(
+	struct xfs_inode        *ip,
+	xfs_off_t               offset,
+	xfs_off_t               len,
+	enum shift_direction	direction)
 {
 	int			done = 0;
 	struct xfs_mount	*mp = ip->i_mount;
@@ -1400,21 +1397,26 @@ xfs_collapse_file_space(
 	struct xfs_bmap_free	free_list;
 	xfs_fsblock_t		first_block;
 	int			committed;
-	xfs_fileoff_t		start_fsb;
+	xfs_fileoff_t		stop_fsb;
 	xfs_fileoff_t		next_fsb;
 	xfs_fileoff_t		shift_fsb;
 
-	ASSERT(xfs_isilocked(ip, XFS_IOLOCK_EXCL));
+	ASSERT(direction == SHIFT_LEFT || direction == SHIFT_RIGHT);
 
-	trace_xfs_collapse_file_space(ip);
+	if (direction == SHIFT_LEFT) {
+		next_fsb = XFS_B_TO_FSB(mp, offset + len);
+		stop_fsb = XFS_B_TO_FSB(mp, VFS_I(ip)->i_size);
+	} else {
+		/*
+		 * If right shift, delegate the work of initialization of
+		 * next_fsb to xfs_bmap_shift_extent as it has ilock held.
+		 */
+		next_fsb = NULLFSBLOCK;
+		stop_fsb = XFS_B_TO_FSB(mp, offset);
+	}
 
-	next_fsb = XFS_B_TO_FSB(mp, offset + len);
 	shift_fsb = XFS_B_TO_FSB(mp, len);
 
-	error = xfs_free_file_space(ip, offset, len);
-	if (error)
-		return error;
-
 	/*
 	 * Trim eofblocks to avoid shifting uninitialized post-eof preallocation
 	 * into the accessible region of the file.
@@ -1427,20 +1429,28 @@ xfs_collapse_file_space(
 
 	/*
 	 * Writeback and invalidate cache for the remainder of the file as we're
-	 * about to shift down every extent from the collapse range to EOF. The
-	 * free of the collapse range above might have already done some of
-	 * this, but we shouldn't rely on it to do anything outside of the range
-	 * that was freed.
+	 * about to shift down every extent from offset to EOF.
 	 */
 	error = filemap_write_and_wait_range(VFS_I(ip)->i_mapping,
-					     offset + len, -1);
+					     offset, -1);
 	if (error)
 		return error;
 	error = invalidate_inode_pages2_range(VFS_I(ip)->i_mapping,
-					(offset + len) >> PAGE_CACHE_SHIFT, -1);
+					offset >> PAGE_CACHE_SHIFT, -1);
 	if (error)
 		return error;
 
+	/*
+	 * The extent shiting code works on extent granularity. So, if
+	 * stop_fsb is not the starting block of extent, we need to split
+	 * the extent at stop_fsb.
+	 */
+	if (direction == SHIFT_RIGHT) {
+		error = xfs_bmap_split_extent(ip, stop_fsb);
+		if (error)
+			return error;
+	}
+
 	while (!error && !done) {
 		tp = xfs_trans_alloc(mp, XFS_TRANS_DIOSTRAT);
 		/*
@@ -1464,7 +1474,7 @@ xfs_collapse_file_space(
 		if (error)
 			goto out;
 
-		xfs_trans_ijoin(tp, ip, 0);
+		xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
 
 		xfs_bmap_init(&free_list, &first_block);
 
@@ -1472,10 +1482,9 @@ xfs_collapse_file_space(
 		 * We are using the write transaction in which max 2 bmbt
 		 * updates are allowed
 		 */
-		start_fsb = next_fsb;
-		error = xfs_bmap_shift_extents(tp, ip, start_fsb, shift_fsb,
-				&done, &next_fsb, &first_block, &free_list,
-				XFS_BMAP_MAX_SHIFT_EXTENTS);
+		error = xfs_bmap_shift_extents(tp, ip, &next_fsb, shift_fsb,
+				&done, stop_fsb, &first_block, &free_list,
+				direction, XFS_BMAP_MAX_SHIFT_EXTENTS);
 		if (error)
 			goto out;
 
@@ -1484,17 +1493,69 @@ xfs_collapse_file_space(
 			goto out;
 
 		error = xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES);
-		xfs_iunlock(ip, XFS_ILOCK_EXCL);
 	}
 
 	return error;
 
 out:
 	xfs_trans_cancel(tp, XFS_TRANS_RELEASE_LOG_RES | XFS_TRANS_ABORT);
-	xfs_iunlock(ip, XFS_ILOCK_EXCL);
 	return error;
 }
 
+/*
+ * xfs_collapse_file_space()
+ *	This routine frees disk space and shift extent for the given file.
+ *	The first thing we do is to free data blocks in the specified range
+ *	by calling xfs_free_file_space(). It would also sync dirty data
+ *	and invalidate page cache over the region on which collapse range
+ *	is working. And Shift extent records to the left to cover a hole.
+ * RETURNS:
+ *	0 on success
+ *	errno on error
+ *
+ */
+int
+xfs_collapse_file_space(
+	struct xfs_inode	*ip,
+	xfs_off_t		offset,
+	xfs_off_t		len)
+{
+	int error;
+
+	ASSERT(xfs_isilocked(ip, XFS_IOLOCK_EXCL));
+	trace_xfs_collapse_file_space(ip);
+
+	error = xfs_free_file_space(ip, offset, len);
+	if (error)
+		return error;
+
+	return xfs_shift_file_space(ip, offset, len, SHIFT_LEFT);
+}
+
+/*
+ * xfs_insert_file_space()
+ *	This routine create hole space by shifting extents for the given file.
+ *	The first thing we do is to sync dirty data and invalidate page cache
+ *	over the region on which insert range is working. And split an extent
+ *	to two extents at given offset by calling xfs_bmap_split_extent.
+ *	And shift all extent records which are laying between [offset,
+ *	last allocated extent] to the right to reserve hole range.
+ * RETURNS:
+ *	0 on success
+ *	errno on error
+ */
+int
+xfs_insert_file_space(
+	struct xfs_inode	*ip,
+	loff_t			offset,
+	loff_t			len)
+{
+	ASSERT(xfs_isilocked(ip, XFS_IOLOCK_EXCL));
+	trace_xfs_insert_file_space(ip);
+
+	return xfs_shift_file_space(ip, offset, len, SHIFT_RIGHT);
+}
+
 /*
  * We need to check that the format of the data fork in the temporary inode is
  * valid for the target inode before doing the swap. This is not a problem with

fs/xfs/xfs_bmap_util.h

@@ -63,6 +63,8 @@ int	xfs_zero_file_space(struct xfs_inode *ip, xfs_off_t offset,
 			    xfs_off_t len);
 int	xfs_collapse_file_space(struct xfs_inode *, xfs_off_t offset,
 				xfs_off_t len);
+int	xfs_insert_file_space(struct xfs_inode *, xfs_off_t offset,
+				xfs_off_t len);
 
 /* EOF block manipulation functions */
 bool	xfs_can_free_eofblocks(struct xfs_inode *ip, bool force);

fs/xfs/xfs_file.c

@@ -822,6 +822,11 @@ xfs_file_write_iter(
 	return ret;
 }
 
+#define	XFS_FALLOC_FL_SUPPORTED						\
+		(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE |		\
+		 FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_ZERO_RANGE |	\
+		 FALLOC_FL_INSERT_RANGE)
+
 STATIC long
 xfs_file_fallocate(
 	struct file		*file,
@@ -835,11 +840,11 @@ xfs_file_fallocate(
 	enum xfs_prealloc_flags	flags = 0;
 	uint			iolock = XFS_IOLOCK_EXCL;
 	loff_t			new_size = 0;
+	bool			do_file_insert = 0;
 
 	if (!S_ISREG(inode->i_mode))
 		return -EINVAL;
-	if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE |
-		     FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_ZERO_RANGE))
+	if (mode & ~XFS_FALLOC_FL_SUPPORTED)
 		return -EOPNOTSUPP;
 
 	xfs_ilock(ip, iolock);
@@ -876,6 +881,27 @@ xfs_file_fallocate(
 		error = xfs_collapse_file_space(ip, offset, len);
 		if (error)
 			goto out_unlock;
+	} else if (mode & FALLOC_FL_INSERT_RANGE) {
+		unsigned blksize_mask = (1 << inode->i_blkbits) - 1;
+
+		new_size = i_size_read(inode) + len;
+		if (offset & blksize_mask || len & blksize_mask) {
+			error = -EINVAL;
+			goto out_unlock;
+		}
+
+		/* check the new inode size does not wrap through zero */
+		if (new_size > inode->i_sb->s_maxbytes) {
+			error = -EFBIG;
+			goto out_unlock;
+		}
+
+		/* Offset should be less than i_size */
+		if (offset >= i_size_read(inode)) {
+			error = -EINVAL;
+			goto out_unlock;
+		}
+		do_file_insert = 1;
 	} else {
 		flags |= XFS_PREALLOC_SET;
 
@@ -910,8 +936,19 @@ xfs_file_fallocate(
 		iattr.ia_valid = ATTR_SIZE;
 		iattr.ia_size = new_size;
 		error = xfs_setattr_size(ip, &iattr);
+		if (error)
+			goto out_unlock;
 	}
 
+	/*
+	 * Perform hole insertion now that the file size has been
+	 * updated so that if we crash during the operation we don't
+	 * leave shifted extents past EOF and hence losing access to
+	 * the data that is contained within them.
+	 */
+	if (do_file_insert)
+		error = xfs_insert_file_space(ip, offset, len);
+
 out_unlock:
 	xfs_iunlock(ip, iolock);
 	return error;

fs/xfs/xfs_trace.h

@@ -664,6 +664,7 @@ DEFINE_INODE_EVENT(xfs_alloc_file_space);
 DEFINE_INODE_EVENT(xfs_free_file_space);
 DEFINE_INODE_EVENT(xfs_zero_file_space);
 DEFINE_INODE_EVENT(xfs_collapse_file_space);
+DEFINE_INODE_EVENT(xfs_insert_file_space);
 DEFINE_INODE_EVENT(xfs_readdir);
 #ifdef CONFIG_XFS_POSIX_ACL
 DEFINE_INODE_EVENT(xfs_get_acl);

include/linux/falloc.h

@@ -21,4 +21,10 @@ struct space_resv {
 #define FS_IOC_RESVSP		_IOW('X', 40, struct space_resv)
 #define FS_IOC_RESVSP64		_IOW('X', 42, struct space_resv)
 
+#define	FALLOC_FL_SUPPORTED_MASK	(FALLOC_FL_KEEP_SIZE |		\
+					 FALLOC_FL_PUNCH_HOLE |		\
+					 FALLOC_FL_COLLAPSE_RANGE |	\
+					 FALLOC_FL_ZERO_RANGE |		\
+					 FALLOC_FL_INSERT_RANGE)
+
 #endif /* _FALLOC_H_ */

include/uapi/linux/falloc.h

@@ -41,4 +41,21 @@
  */
 #define FALLOC_FL_ZERO_RANGE		0x10
 
+/*
+ * FALLOC_FL_INSERT_RANGE is use to insert space within the file size without
+ * overwriting any existing data. The contents of the file beyond offset are
+ * shifted towards right by len bytes to create a hole.  As such, this
+ * operation will increase the size of the file by len bytes.
+ *
+ * Different filesystems may implement different limitations on the granularity
+ * of the operation. Most will limit operations to filesystem block size
+ * boundaries, but this boundary may be larger or smaller depending on
+ * the filesystem and/or the configuration of the filesystem or file.
+ *
+ * Attempting to insert space using this flag at OR beyond the end of
+ * the file is considered an illegal operation - just use ftruncate(2) or
+ * fallocate(2) with mode 0 for such type of operations.
+ */
+#define FALLOC_FL_INSERT_RANGE		0x20
+
 #endif /* _UAPI_FALLOC_H_ */