On 2018/10/11 11:05, Jaegeuk Kim wrote: > On 10/10, Jaegeuk Kim wrote: >> On 10/11, Sahitya Tummala wrote: >>> On Wed, Oct 10, 2018 at 02:34:02PM -0700, Jaegeuk Kim wrote: >>>> On 10/10, Sahitya Tummala wrote: >>>>> 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 <stumm...@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); >>>> >>>> Do we need this? IIRC, DIO would give create=1. >>> >>> Yes, we need it. When we are overwriting an existing file, DIO calls >>> f2fs_map_blocks() with create=0. From the DIO code, I see that this happens >>> because blockdev_direct_IO() passes this dio flag DIO_SKIP_HOLES. And then >>> in get_more_blocks(), below code updates create=0, when we are overwriting >>> an existing file. >>> >>> create = dio->op == REQ_OP_WRITE; >>> if (dio->flags & DIO_SKIP_HOLES) { >>> if (fs_startblk <= ((i_size_read(dio->inode) - 1) >> >>> i_blkbits)) >>> create = 0; >>> } >>> >>> ret = (*sdio->get_block)(dio->inode, fs_startblk, >>> map_bh, create); >>> >> >> Got it. >> How about this? >> > > Sorry, this is v2. > >>From b78dd7b2e0317be18716b9496269e9792829f63e Mon Sep 17 00:00:00 2001 > From: Sahitya Tummala <stumm...@codeaurora.org> > Date: Wed, 10 Oct 2018 10:56:22 +0530 > Subject: [PATCH] f2fs: fix data corruption issue with hardware encryption > > 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 <stumm...@codeaurora.org> > Signed-off-by: Jaegeuk Kim <jaeg...@kernel.org>
Nice catch! Reviewed-by: Chao Yu <yuch...@huawei.com> Thanks, _______________________________________________ Linux-f2fs-devel mailing list Linux-f2fs-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel