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Subject[PATCH] f2fs: fix data corruption issue with hardware encryption
Date
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@codeaurora.org>
---
fs/f2fs/data.c | 12 ++++++++++++
1 file changed, 12 insertions(+)

diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 9ef6f1f..7b2fef0 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -1028,6 +1028,12 @@ int f2fs_map_blocks(struct inode *inode, struct f2fs_map_blocks *map,
map->m_pblk = ei.blk + pgofs - ei.fofs;
map->m_len = min((pgoff_t)maxblocks, ei.fofs + ei.len - pgofs);
map->m_flags = F2FS_MAP_MAPPED;
+ /* for HW encryption, but to avoid potential issue in future */
+ if (flag == F2FS_GET_BLOCK_DIO) {
+ blkaddr = map->m_pblk;
+ for (; blkaddr < map->m_pblk + map->m_len; blkaddr++)
+ f2fs_wait_on_block_writeback(sbi, blkaddr);
+ }
if (map->m_next_extent)
*map->m_next_extent = pgofs + map->m_len;
goto out;
@@ -1188,6 +1194,12 @@ 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) {
+ blkaddr = map->m_pblk;
+ for (; blkaddr < map->m_pblk + map->m_len; blkaddr++)
+ f2fs_wait_on_block_writeback(sbi, blkaddr);
+ }
if (flag == F2FS_GET_BLOCK_PRECACHE) {
if (map->m_flags & F2FS_MAP_MAPPED) {
unsigned int ofs = start_pgofs - map->m_lblk;
--
Qualcomm India Private Limited, on behalf of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project.
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