1 files changed, 132 insertions, 3 deletions

diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index cb002c067630..dbddc7935f33 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -765,6 +765,132 @@ static int punch_hole(struct inode *inode, loff_t offset, loff_t len)
 	return ret;
 }
 
+static int f2fs_do_collapse(struct inode *inode, pgoff_t start, pgoff_t end)
+{
+	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
+	struct dnode_of_data dn;
+	pgoff_t nrpages = (i_size_read(inode) + PAGE_SIZE - 1) / PAGE_SIZE;
+	int ret = 0;
+
+	f2fs_lock_op(sbi);
+
+	for (; end < nrpages; start++, end++) {
+		block_t new_addr, old_addr;
+
+		set_new_dnode(&dn, inode, NULL, NULL, 0);
+		ret = get_dnode_of_data(&dn, end, LOOKUP_NODE_RA);
+		if (ret && ret != -ENOENT) {
+			goto out;
+		} else if (ret == -ENOENT) {
+			new_addr = NULL_ADDR;
+		} else {
+			new_addr = dn.data_blkaddr;
+			truncate_data_blocks_range(&dn, 1);
+			f2fs_put_dnode(&dn);
+		}
+
+		if (new_addr == NULL_ADDR) {
+			set_new_dnode(&dn, inode, NULL, NULL, 0);
+			ret = get_dnode_of_data(&dn, start, LOOKUP_NODE_RA);
+			if (ret && ret != -ENOENT)
+				goto out;
+			else if (ret == -ENOENT)
+				continue;
+
+			if (dn.data_blkaddr == NULL_ADDR) {
+				f2fs_put_dnode(&dn);
+				continue;
+			} else {
+				truncate_data_blocks_range(&dn, 1);
+			}
+
+			f2fs_put_dnode(&dn);
+		} else {
+			struct page *ipage;
+
+			ipage = get_node_page(sbi, inode->i_ino);
+			if (IS_ERR(ipage)) {
+				ret = PTR_ERR(ipage);
+				goto out;
+			}
+
+			set_new_dnode(&dn, inode, ipage, NULL, 0);
+			ret = f2fs_reserve_block(&dn, start);
+			if (ret)
+				goto out;
+
+			old_addr = dn.data_blkaddr;
+			if (old_addr != NEW_ADDR && new_addr == NEW_ADDR) {
+				dn.data_blkaddr = NULL_ADDR;
+				f2fs_update_extent_cache(&dn);
+				invalidate_blocks(sbi, old_addr);
+
+				dn.data_blkaddr = new_addr;
+				set_data_blkaddr(&dn);
+			} else if (new_addr != NEW_ADDR) {
+				struct node_info ni;
+				struct f2fs_summary sum;
+
+				get_node_info(sbi, dn.nid, &ni);
+				set_summary(&sum, dn.nid, dn.ofs_in_node,
+								ni.version);
+
+				f2fs_replace_block(sbi, &sum, old_addr,
+								new_addr, true);
+
+				dn.data_blkaddr = new_addr;
+				set_data_blkaddr(&dn);
+				f2fs_update_extent_cache(&dn);
+			}
+
+			f2fs_put_dnode(&dn);
+		}
+	}
+	ret = 0;
+out:
+	f2fs_unlock_op(sbi);
+	return ret;
+}
+
+static int f2fs_collapse_range(struct inode *inode, loff_t offset, loff_t len)
+{
+	pgoff_t pg_start, pg_end;
+	loff_t new_size;
+	int ret;
+
+	if (!S_ISREG(inode->i_mode))
+		return -EINVAL;
+
+	if (offset + len >= i_size_read(inode))
+		return -EINVAL;
+
+	/* collapse range should be aligned to block size of f2fs. */
+	if (offset & (F2FS_BLKSIZE - 1) || len & (F2FS_BLKSIZE - 1))
+		return -EINVAL;
+
+	pg_start = offset >> PAGE_CACHE_SHIFT;
+	pg_end = (offset + len) >> PAGE_CACHE_SHIFT;
+
+	/* write out all dirty pages from offset */
+	ret = filemap_write_and_wait_range(inode->i_mapping, offset, LLONG_MAX);
+	if (ret)
+		return ret;
+
+	truncate_pagecache(inode, offset);
+
+	ret = f2fs_do_collapse(inode, pg_start, pg_end);
+	if (ret)
+		return ret;
+
+	new_size = i_size_read(inode) - len;
+
+	ret = truncate_blocks(inode, new_size, true);
+	if (!ret)
+		i_size_write(inode, new_size);
+
+	return ret;
+}
+
 static int expand_inode_data(struct inode *inode, loff_t offset,
 					loff_t len, int mode)
 {
@@ -832,7 +958,8 @@ static long f2fs_fallocate(struct file *file, int mode,
 	struct inode *inode = file_inode(file);
 	long ret = 0;
 
-	if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
+	if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE |
+			FALLOC_FL_COLLAPSE_RANGE))
 		return -EOPNOTSUPP;
 
 	mutex_lock(&inode->i_mutex);
@@ -842,9 +969,11 @@ static long f2fs_fallocate(struct file *file, int mode,
 			goto out;
 
 		ret = punch_hole(inode, offset, len);
-	}
-	else
+	} else if (mode & FALLOC_FL_COLLAPSE_RANGE) {
+		ret = f2fs_collapse_range(inode, offset, len);
+	} else {
 		ret = expand_inode_data(inode, offset, len, mode);
+	}
 
 	if (!ret) {
 		inode->i_mtime = inode->i_ctime = CURRENT_TIME;