On 2022/10/20 15:27, zhangqilong via Linux-f2fs-devel wrote:
On 2022/10/18 10:45, Zhang Qilong wrote:
In the following case:
process 1 process 2
->open A
->mmap
->read # the first time
->ioctl w/h F2FS_IOC_MOVE_RANGE
# (range A->B)
->read # the second time
How about checking B as well? Previous mapped data can still be accessed
after F2FS_IOC_MOVE_RANGE?
Hi
I have checked B as well. Previous mapped data can't be accessed after
F2FS_IOC_MOVE_RANGE.
I doubt that we didn't call flush_dcache_page() in below branch, so user may
see stall data after F2FS_IOC_MOVE_RANGE? Am I missing something?
__clone_blkaddrs()
{
...
} else {
struct page *psrc, *pdst;
psrc = f2fs_get_lock_data_page(src_inode,
src + i, true);
if (IS_ERR(psrc))
return PTR_ERR(psrc);
pdst = f2fs_get_new_data_page(dst_inode, NULL, dst + i,
true);
if (IS_ERR(pdst)) {
f2fs_put_page(psrc, 1);
return PTR_ERR(pdst);
}
memcpy_page(pdst, 0, psrc, 0, PAGE_SIZE);
set_page_dirty(pdst);
f2fs_put_page(pdst, 1);
f2fs_put_page(psrc, 1);
ret = f2fs_truncate_hole(src_inode,
src + i, src + i + 1);
if (ret)
return ret;
i++;
}
...
}
Thanks,
In addition, this patch could be applied to mainline if possible?
Thanks
Thanks,
We will read old data at the second time. The root cause is that user
still can see the previous source data after being moved. We fix it by
adding truncating after __exchange_data_block.
Fixes: 4dd6f977fc77 ("f2fs: support an ioctl to move a range of data
blocks")
Signed-off-by: Zhang Qilong <zhangqilo...@huawei.com>
---
v2:
- moving truncating to the range of f2fs_lock_op()
v3:
- modify the title and commit message
---
fs/f2fs/file.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c index
82cda1258227..e9dfa41baf9e 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -2824,6 +2824,7 @@ static int f2fs_move_file_range(struct file *file_in,
loff_t pos_in,
goto out_src;
}
+ filemap_invalidate_lock(src->i_mapping);
f2fs_lock_op(sbi);
ret = __exchange_data_block(src, dst, pos_in >> F2FS_BLKSIZE_BITS,
pos_out >> F2FS_BLKSIZE_BITS,
@@ -2835,7 +2836,9 @@ static int f2fs_move_file_range(struct file *file_in,
loff_t pos_in,
else if (dst_osize != dst->i_size)
f2fs_i_size_write(dst, dst_osize);
}
+ truncate_pagecache_range(src, pos_in, pos_in + len - 1);
f2fs_unlock_op(sbi);
+ filemap_invalidate_unlock(src->i_mapping);
if (src != dst)
f2fs_up_write(&F2FS_I(dst)->i_gc_rwsem[WRITE]);
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