Re: [PATCH 2/7] repair: Protect bad inode list with mutex

Darrick J. Wong
2020-10-22T05:45:21Z

On Thu, Oct 22, 2020 at 04:15:32PM +1100, Dave Chinner wrote:
> From: Dave Chinner <dchinner@redhat.com>
>
> To enable phase 6 parallelisation, we need to protect the bad inode
> list from concurrent modification and/or access. Wrap it with a
> mutex and clean up the nasty typedefs.
>
> Signed-off-by: Dave Chinner <dchinner@redhat.com>

/methinks the typedef removal ought to be a separate commit,
but otherwise:

Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>

--D

> ---
> repair/dir2.c | 32 +++++++++++++++++++++-----------
> 1 file changed, 21 insertions(+), 11 deletions(-)
>
> diff --git a/repair/dir2.c b/repair/dir2.c
> index eabdb4f2d497..23333e59a382 100644
> --- a/repair/dir2.c
> +++ b/repair/dir2.c
> @@ -20,40 +20,50 @@
> * Known bad inode list. These are seen when the leaf and node
> * block linkages are incorrect.
> */
> -typedef struct dir2_bad {
> +struct dir2_bad {
> xfs_ino_t ino;
> struct dir2_bad *next;
> -} dir2_bad_t;
> +};
>
> -static dir2_bad_t *dir2_bad_list;
> +static struct dir2_bad *dir2_bad_list;
> +pthread_mutex_t dir2_bad_list_lock = PTHREAD_MUTEX_INITIALIZER;
>
> static void
> dir2_add_badlist(
> xfs_ino_t ino)
> {
> - dir2_bad_t *l;
> + struct dir2_bad *l;
>
> - if ((l = malloc(sizeof(dir2_bad_t))) == NULL) {
> + l = malloc(sizeof(*l));
> + if (!l) {
> do_error(
> _("malloc failed (%zu bytes) dir2_add_badlist:ino %" PRIu64 "\n"),
> - sizeof(dir2_bad_t), ino);
> + sizeof(*l), ino);
> exit(1);
> }
> + pthread_mutex_lock(&dir2_bad_list_lock);
> l->next = dir2_bad_list;
> dir2_bad_list = l;
> l->ino = ino;
> + pthread_mutex_unlock(&dir2_bad_list_lock);
> }
>
> int
> dir2_is_badino(
> xfs_ino_t ino)
> {
> - dir2_bad_t *l;
> + struct dir2_bad *l;
> + int ret = 0;
>
> - for (l = dir2_bad_list; l; l = l->next)
> - if (l->ino == ino)
> - return 1;
> - return 0;
> + pthread_mutex_lock(&dir2_bad_list_lock);
> + for (l = dir2_bad_list; l; l = l->next) {
> + if (l->ino == ino) {
> + ret = 1;
> + break;
> + }
> + }
> + pthread_mutex_unlock(&dir2_bad_list_lock);
> + return ret;
> }
>
> /*
> --
> 2.28.0
>