On Wed 08-09-21 10:46:05, Chenyuan Mi wrote:
> After successfully creating handle by __ext4_journal_start_sb(),
> the function forgets to decrease the refcount of handle in several
> paths, causing refcount leak.
>
> Fix this issue by recording a flag when successfully getting handle
> by __ext4_journal_start_sb(), and decrease the refcount of handle
> when exiting this function if holding the flag.
>
> Signed-off-by: Chenyuan Mi <cymi20@xxxxxxxxxxxx>
> Signed-off-by: Xiyu Yang <xiyuyang19@xxxxxxxxxxxx>
> Signed-off-by: Xin Tan <tanxin.ctf@xxxxxxxxx>
I'm sorry but this patch is wrong. We are expected to return with handle
running from __ext4_new_inode(). Please have a look into callers of
ext4_new_inode() and ext4_new_inode_start_handle() how they use and then
stop the handle. And similarly as for the second patch I'd note that even a
small amount of testing would show you that this patch does not work.
Honza
>
> ---
> fs/ext4/ialloc.c | 7 ++++++-
> 1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
> index f73e5eb43eae..7563b892c64f 100644
> --- a/fs/ext4/ialloc.c
> +++ b/fs/ext4/ialloc.c
> @@ -944,6 +944,7 @@ struct inode *__ext4_new_inode(struct user_namespace *mnt_userns,
> ext4_group_t flex_group;
> struct ext4_group_info *grp = NULL;
> bool encrypt = false;
> + bool create_handle = false;
>
> /* Cannot create files in a deleted directory */
> if (!dir || !dir->i_nlink)
> @@ -1085,6 +1086,7 @@ struct inode *__ext4_new_inode(struct user_namespace *mnt_userns,
> ext4_std_error(sb, err);
> goto out;
> }
> + create_handle = true;
> }
> BUFFER_TRACE(inode_bitmap_bh, "get_write_access");
> err = ext4_journal_get_write_access(handle, sb, inode_bitmap_bh,
> @@ -1345,7 +1347,8 @@ struct inode *__ext4_new_inode(struct user_namespace *mnt_userns,
> ext4_std_error(sb, err);
> goto fail_free_drop;
> }
> -
> + if (create_handle)
> + ext4_journal_stop(handle);
> ext4_debug("allocating inode %lu\n", inode->i_ino);
> trace_ext4_allocate_inode(inode, dir, mode);
> brelse(inode_bitmap_bh);
> @@ -1357,6 +1360,8 @@ struct inode *__ext4_new_inode(struct user_namespace *mnt_userns,
> clear_nlink(inode);
> unlock_new_inode(inode);
> out:
> + if (create_handle)
> + ext4_journal_stop(handle);
> dquot_drop(inode);
> inode->i_flags |= S_NOQUOTA;
> iput(inode);
> --
> 2.17.1
>
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR
