ext4: propagate errors from ext4_find_extent() in ext4_insert_range()

Even though ext4_find_extent() returns an error, ext4_insert_range() still
returns 0. This may confuse the user as to why fallocate returns success,
but the contents of the file are not as expected. So propagate the error
returned by ext4_find_extent() to avoid inconsistencies.

Fixes: 331573f ("ext4: Add support FALLOC_FL_INSERT_RANGE for fallocate")
Cc: [email protected]
Signed-off-by: Baokun Li <[email protected]>
Reviewed-by: Jan Kara <[email protected]>
Reviewed-by: Ojaswin Mujoo <[email protected]>
Tested-by: Ojaswin Mujoo <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Theodore Ts'o <[email protected]>

Author: LiBaokun96

fs/ext4/extents.c

@@ -5541,6 +5541,7 @@ static int ext4_insert_range(struct file *file, loff_t offset, loff_t len)
 	path = ext4_find_extent(inode, offset_lblk, NULL, 0);
 	if (IS_ERR(path)) {
 		up_write(&EXT4_I(inode)->i_data_sem);
+		ret = PTR_ERR(path);
 		goto out_stop;
 	}