Hi Pengyang,
On 2016/5/16 18:40, Hou Pengyang wrote:
> When collecting data segment(gc_data_segment), there is a race condition
> between evict and phases of gc:
> 0) ra_node_page(dnode)
> 1) ra_node_page(inode)
> <--- evict the inode
> 2) f2fs_iget get the inode and add it to gc_list
> 3) move_data_page
>
> In step 2), f2fs_iget does NOT find the inode and allocs a new inode as
> result,
If inode was unlinked and then be evicted, f2fs_iget should fail when reading
inode's page as blkaddr of this node is null.
If inode still have non-zero nlink value and then be evicted, we should allow gc
thread to reference this inode for moving its data pages.
Thanks,
> which is not resonable.
>
> This patch changes f2fs_iget to ilookup. when no inode is found, no new inode
> is
> created.
>
> Signed-off-by: Hou Pengyang <houpengy...@huawei.com>
> ---
> fs/f2fs/gc.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
> index 38d56f6..6e73193 100644
> --- a/fs/f2fs/gc.c
> +++ b/fs/f2fs/gc.c
> @@ -717,8 +717,8 @@ next_step:
> ofs_in_node = le16_to_cpu(entry->ofs_in_node);
>
> if (phase == 2) {
> - inode = f2fs_iget(sb, dni.ino);
> - if (IS_ERR(inode) || is_bad_inode(inode))
> + inode = ilookup(sb, dni.ino);
> + if (!inode || IS_ERR(inode) || is_bad_inode(inode))
> continue;
>
> /* if encrypted inode, let's go phase 3 */
>
