On 9/10/25 21:58, wangzijie wrote:
> When the data layout is like this:
> dnode1: dnode2:
> [0] A [0] NEW_ADDR
> [1] A+1 [1] 0x0
> ... ....
> [1016] A+1016
> [1017] B (B!=A+1017) [1017] 0x0
>
> We can build this kind of layout by following steps(with i_extra_isize:36):
> ./f2fs_io write 1 0 1881 rand dsync testfile
> ./f2fs_io write 1 1881 1 rand buffered testfile
> ./f2fs_io fallocate 0 7708672 4096 testfile
>
> And when we map first data block in dnode2, we will get wrong extent_info
> data:
> map->m_len = 1
> ofs = start_pgofs - map->m_lblk = 1882 - 1881 = 1
>
> ei.fofs = start_pgofs = 1882
> ei.len = map->m_len - ofs = 1 - 1 = 0
>
> Fix it by skipping updating this kind of extent info.
>
> Signed-off-by: wangzijie <wangzij...@honor.com>
> ---
> fs/f2fs/data.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> index 7961e0ddf..b8bb71852 100644
> --- a/fs/f2fs/data.c
> +++ b/fs/f2fs/data.c
> @@ -1649,6 +1649,9 @@ int f2fs_map_blocks(struct inode *inode, struct
> f2fs_map_blocks *map, int flag)
>
> switch (flag) {
> case F2FS_GET_BLOCK_PRECACHE:
> + if (__is_valid_data_blkaddr(map->m_pblk) &&
> + start_pgofs - map->m_lblk == map->m_len)
> + map->m_flags &= ~F2FS_MAP_MAPPED;
It looks we missed to reset value for map variable in f2fs_precache_extents(),
what do you think of this?
---
fs/f2fs/file.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 1aae4361d0a8..2b14151d4130 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -3599,7 +3599,7 @@ static int f2fs_ioc_io_prio(struct file *filp, unsigned
long arg)
int f2fs_precache_extents(struct inode *inode)
{
struct f2fs_inode_info *fi = F2FS_I(inode);
- struct f2fs_map_blocks map;
+ struct f2fs_map_blocks map = { 0 };
pgoff_t m_next_extent;
loff_t end;
int err;
@@ -3617,6 +3617,8 @@ int f2fs_precache_extents(struct inode *inode)
while (map.m_lblk < end) {
map.m_len = end - map.m_lblk;
+ map.m_pblk = 0;
+ map.m_flags = 0;
f2fs_down_write(&fi->i_gc_rwsem[WRITE]);
err = f2fs_map_blocks(inode, &map, F2FS_GET_BLOCK_PRECACHE);
--
2.49.0
Thanks,
> goto sync_out;
> case F2FS_GET_BLOCK_BMAP:
> map->m_pblk = 0;
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