[PATCH] f2fs: fix data corruption issue with hardware encryption

[Sahitya Tummala]

Direct IO can be used in case of hardware encryption. The following
scenario results into data corruption issue in this path -

Thread A -                          Thread B-
-> write file#1 in direct IO
                                    -> GC gets kicked in
                                    -> GC submitted bio on meta mapping
				       for file#1, but pending completion
-> write file#1 again with new data
   in direct IO
                                    -> GC bio gets completed now
                                    -> GC writes old data to the new
                                       location and thus file#1 is
				       corrupted.

Fix this by submitting and waiting for pending io on meta mapping
for direct IO case in f2fs_map_blocks().

Signed-off-by: Sahitya Tummala <stummala@xxxxxxxxxxxxxx>
Signed-off-by: Jaegeuk Kim <jaegeuk@xxxxxxxxxx>
---
 fs/f2fs/data.c    | 11 +++++++++++
 fs/f2fs/f2fs.h    |  2 ++
 fs/f2fs/segment.c |  7 +++++++
 3 files changed, 20 insertions(+)

diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index be19257d9e36..8952f2d610a6 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -1030,6 +1030,11 @@ int f2fs_map_blocks(struct inode *inode, struct f2fs_map_blocks *map,
 		map->m_flags = F2FS_MAP_MAPPED;
 		if (map->m_next_extent)
 			*map->m_next_extent = pgofs + map->m_len;
+
+		/* for hardware encryption, but to avoid potential issue in future */
+		if (flag == F2FS_GET_BLOCK_DIO)
+			f2fs_wait_on_block_writeback_range(inode,
+						map->m_pblk, map->m_len);
 		goto out;
 	}
 
@@ -1188,6 +1193,12 @@ int f2fs_map_blocks(struct inode *inode, struct f2fs_map_blocks *map,
 	goto next_dnode;
 
 sync_out:
+
+	/* for hardware encryption, but to avoid potential issue in future */
+	if (flag == F2FS_GET_BLOCK_DIO && map->m_flags & F2FS_MAP_MAPPED)
+		f2fs_wait_on_block_writeback_range(inode,
+						map->m_pblk, map->m_len);
+
 	if (flag == F2FS_GET_BLOCK_PRECACHE) {
 		if (map->m_flags & F2FS_MAP_MAPPED) {
 			unsigned int ofs = start_pgofs - map->m_lblk;
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 7693b1a2072e..4a608a71c360 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -2986,6 +2986,8 @@ void f2fs_allocate_data_block(struct f2fs_sb_info *sbi, struct page *page,
 void f2fs_wait_on_page_writeback(struct page *page,
 			enum page_type type, bool ordered);
 void f2fs_wait_on_block_writeback(struct inode *inode, block_t blkaddr);
+void f2fs_wait_on_block_writeback_range(struct inode *inode, block_t blkaddr,
+								block_t len);
 void f2fs_write_data_summaries(struct f2fs_sb_info *sbi, block_t start_blk);
 void f2fs_write_node_summaries(struct f2fs_sb_info *sbi, block_t start_blk);
 int f2fs_lookup_journal_in_cursum(struct f2fs_journal *journal, int type,
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 805c8310d7b0..2a75eb961982 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -3301,6 +3301,13 @@ void f2fs_wait_on_block_writeback(struct inode *inode, block_t blkaddr)
 	}
 }
 
+void f2fs_wait_on_block_writeback_range(struct inode *inode, block_t blkaddr,
+								block_t len)
+{
+	for (; blkaddr < blkaddr + len; blkaddr++)
+		f2fs_wait_on_block_writeback(inode, blkaddr);
+}
+
 static int read_compacted_summaries(struct f2fs_sb_info *sbi)
 {
 	struct f2fs_checkpoint *ckpt = F2FS_CKPT(sbi);
-- 
2.19.0.605.g01d371f741-goog