On Sun, May 10, 2020 at 09:24:04AM +0200, Christoph Hellwig wrote:
> Move freeing the dynamically allocated attr and COW fork, as well
> as zeroing the pointers where actually needed into the callers, and
> just pass the xfs_ifork structure to xfs_idestroy_fork. Simplify
> the kmem_free calls by not checking for NULL first, and not zeroing
> the pointers in structure that are about to be freed (either the
> ifork or the containing inode in case of the data fork).
>
> Signed-off-by: Christoph Hellwig <hch@xxxxxx>
> ---
> fs/xfs/libxfs/xfs_attr_leaf.c | 7 +++----
> fs/xfs/libxfs/xfs_inode_buf.c | 2 +-
> fs/xfs/libxfs/xfs_inode_fork.c | 36 +++++++++-------------------------
> fs/xfs/libxfs/xfs_inode_fork.h | 2 +-
> fs/xfs/xfs_attr_inactive.c | 7 +++++--
> fs/xfs/xfs_icache.c | 15 ++++++++------
> 6 files changed, 28 insertions(+), 41 deletions(-)
>
...
> diff --git a/fs/xfs/libxfs/xfs_inode_fork.c b/fs/xfs/libxfs/xfs_inode_fork.c
> index 6562f2bcd15cc..577cc20e03170 100644
> --- a/fs/xfs/libxfs/xfs_inode_fork.c
> +++ b/fs/xfs/libxfs/xfs_inode_fork.c
> @@ -495,38 +495,20 @@ xfs_idata_realloc(
>
> void
> xfs_idestroy_fork(
> - xfs_inode_t *ip,
> - int whichfork)
> + struct xfs_ifork *ifp)
> {
> - struct xfs_ifork *ifp;
> -
> - ifp = XFS_IFORK_PTR(ip, whichfork);
> - if (ifp->if_broot != NULL) {
> - kmem_free(ifp->if_broot);
> - ifp->if_broot = NULL;
> - }
> + kmem_free(ifp->if_broot);
I think this function should still reset the pointers within the ifp
that it frees (if_broot and if_data below), particularly as long as
there are multiple callers that pass the data fork because it is not
immediately/independently freed. IOW, it's not clear if something
happens to reset i_mode between when xfs_inode_from_disk() might fail
and destroy the data fork, and when the inode is ultimately freed and we
look at i_mode to determine whether to destroy the data fork.
Brian
>
> /*
> - * If the format is local, then we can't have an extents
> - * array so just look for an inline data array. If we're
> - * not local then we may or may not have an extents list,
> - * so check and free it up if we do.
> + * If the format is local, then we can't have an extents array so just
> + * look for an inline data array. If we're not local then we may or may
> + * not have an extents list, so check and free it up if we do.
> */
> if (ifp->if_format == XFS_DINODE_FMT_LOCAL) {
> - if (ifp->if_u1.if_data != NULL) {
> - kmem_free(ifp->if_u1.if_data);
> - ifp->if_u1.if_data = NULL;
> - }
> - } else if ((ifp->if_flags & XFS_IFEXTENTS) && ifp->if_height) {
> - xfs_iext_destroy(ifp);
> - }
> -
> - if (whichfork == XFS_ATTR_FORK) {
> - kmem_cache_free(xfs_ifork_zone, ip->i_afp);
> - ip->i_afp = NULL;
> - } else if (whichfork == XFS_COW_FORK) {
> - kmem_cache_free(xfs_ifork_zone, ip->i_cowfp);
> - ip->i_cowfp = NULL;
> + kmem_free(ifp->if_u1.if_data);
> + } else if (ifp->if_flags & XFS_IFEXTENTS) {
> + if (ifp->if_height)
> + xfs_iext_destroy(ifp);
> }
> }
>
> diff --git a/fs/xfs/libxfs/xfs_inode_fork.h b/fs/xfs/libxfs/xfs_inode_fork.h
> index d849cca103edd..a4953e95c4f3f 100644
> --- a/fs/xfs/libxfs/xfs_inode_fork.h
> +++ b/fs/xfs/libxfs/xfs_inode_fork.h
> @@ -86,7 +86,7 @@ int xfs_iformat_data_fork(struct xfs_inode *, struct xfs_dinode *);
> int xfs_iformat_attr_fork(struct xfs_inode *, struct xfs_dinode *);
> void xfs_iflush_fork(struct xfs_inode *, struct xfs_dinode *,
> struct xfs_inode_log_item *, int);
> -void xfs_idestroy_fork(struct xfs_inode *, int);
> +void xfs_idestroy_fork(struct xfs_ifork *ifp);
> void xfs_idata_realloc(struct xfs_inode *ip, int64_t byte_diff,
> int whichfork);
> void xfs_iroot_realloc(struct xfs_inode *, int, int);
> diff --git a/fs/xfs/xfs_attr_inactive.c b/fs/xfs/xfs_attr_inactive.c
> index 00ffc46c0bf71..bfad669e6b2f8 100644
> --- a/fs/xfs/xfs_attr_inactive.c
> +++ b/fs/xfs/xfs_attr_inactive.c
> @@ -388,8 +388,11 @@ xfs_attr_inactive(
> xfs_trans_cancel(trans);
> out_destroy_fork:
> /* kill the in-core attr fork before we drop the inode lock */
> - if (dp->i_afp)
> - xfs_idestroy_fork(dp, XFS_ATTR_FORK);
> + if (dp->i_afp) {
> + xfs_idestroy_fork(dp->i_afp);
> + kmem_cache_free(xfs_ifork_zone, dp->i_afp);
> + dp->i_afp = NULL;
> + }
> if (lock_mode)
> xfs_iunlock(dp, lock_mode);
> return error;
> diff --git a/fs/xfs/xfs_icache.c b/fs/xfs/xfs_icache.c
> index c09b3e9eab1da..d806d3bfa8936 100644
> --- a/fs/xfs/xfs_icache.c
> +++ b/fs/xfs/xfs_icache.c
> @@ -87,15 +87,18 @@ xfs_inode_free_callback(
> case S_IFREG:
> case S_IFDIR:
> case S_IFLNK:
> - xfs_idestroy_fork(ip, XFS_DATA_FORK);
> + xfs_idestroy_fork(&ip->i_df);
> break;
> }
>
> - if (ip->i_afp)
> - xfs_idestroy_fork(ip, XFS_ATTR_FORK);
> - if (ip->i_cowfp)
> - xfs_idestroy_fork(ip, XFS_COW_FORK);
> -
> + if (ip->i_afp) {
> + xfs_idestroy_fork(ip->i_afp);
> + kmem_cache_free(xfs_ifork_zone, ip->i_afp);
> + }
> + if (ip->i_cowfp) {
> + xfs_idestroy_fork(ip->i_cowfp);
> + kmem_cache_free(xfs_ifork_zone, ip->i_cowfp);
> + }
> if (ip->i_itemp) {
> ASSERT(!test_bit(XFS_LI_IN_AIL,
> &ip->i_itemp->ili_item.li_flags));
> --
> 2.26.2
>
