Re: [PATCH 04/33] xfs: fix misuse of the XFS_ATTR_INCOMPLETE flag

["Darrick J. Wong" <darrick.wong@oracle.com>]

On Thu, Dec 12, 2019 at 11:54:04AM +0100, Christoph Hellwig wrote:
> XFS_ATTR_INCOMPLETE is a flag in the on-disk attribute format, and thus
> in a different namespace as the ATTR_* flags in xfs_da_args.flags.
> Switch to using a XFS_DA_OP_INCOMPLETE flag in op_flags instead.  Without
> this users might be able to inject this flag into operations using the
> attr by handle ioctl.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>

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

--D

> ---
>  fs/xfs/libxfs/xfs_attr.c      | 2 +-
>  fs/xfs/libxfs/xfs_attr_leaf.c | 4 ++--
>  fs/xfs/libxfs/xfs_da_btree.h  | 4 +++-
>  fs/xfs/libxfs/xfs_da_format.h | 2 --
>  4 files changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
> index 0d7fcc983b3d..2368a1bfe7e8 100644
> --- a/fs/xfs/libxfs/xfs_attr.c
> +++ b/fs/xfs/libxfs/xfs_attr.c
> @@ -1007,7 +1007,7 @@ xfs_attr_node_addname(
>  		 * The INCOMPLETE flag means that we will find the "old"
>  		 * attr, not the "new" one.
>  		 */
> -		args->flags |= XFS_ATTR_INCOMPLETE;
> +		args->op_flags |= XFS_DA_OP_INCOMPLETE;
>  		state = xfs_da_state_alloc();
>  		state->args = args;
>  		state->mp = mp;
> diff --git a/fs/xfs/libxfs/xfs_attr_leaf.c b/fs/xfs/libxfs/xfs_attr_leaf.c
> index 08d4b10ae2d5..fed537a4353d 100644
> --- a/fs/xfs/libxfs/xfs_attr_leaf.c
> +++ b/fs/xfs/libxfs/xfs_attr_leaf.c
> @@ -2403,8 +2403,8 @@ xfs_attr3_leaf_lookup_int(
>  		 * If we are looking for INCOMPLETE entries, show only those.
>  		 * If we are looking for complete entries, show only those.
>  		 */
> -		if ((args->flags & XFS_ATTR_INCOMPLETE) !=
> -		    (entry->flags & XFS_ATTR_INCOMPLETE)) {
> +		if (!!(args->op_flags & XFS_DA_OP_INCOMPLETE) !=
> +		    !!(entry->flags & XFS_ATTR_INCOMPLETE)) {
>  			continue;
>  		}
>  		if (entry->flags & XFS_ATTR_LOCAL) {
> diff --git a/fs/xfs/libxfs/xfs_da_btree.h b/fs/xfs/libxfs/xfs_da_btree.h
> index e16610d1c14f..0f4fbb0889ff 100644
> --- a/fs/xfs/libxfs/xfs_da_btree.h
> +++ b/fs/xfs/libxfs/xfs_da_btree.h
> @@ -89,6 +89,7 @@ typedef struct xfs_da_args {
>  #define XFS_DA_OP_OKNOENT	0x0008	/* lookup/add op, ENOENT ok, else die */
>  #define XFS_DA_OP_CILOOKUP	0x0010	/* lookup to return CI name if found */
>  #define XFS_DA_OP_ALLOCVAL	0x0020	/* lookup to alloc buffer if found  */
> +#define XFS_DA_OP_INCOMPLETE	0x0040	/* lookup INCOMPLETE attr keys */
>  
>  #define XFS_DA_OP_FLAGS \
>  	{ XFS_DA_OP_JUSTCHECK,	"JUSTCHECK" }, \
> @@ -96,7 +97,8 @@ typedef struct xfs_da_args {
>  	{ XFS_DA_OP_ADDNAME,	"ADDNAME" }, \
>  	{ XFS_DA_OP_OKNOENT,	"OKNOENT" }, \
>  	{ XFS_DA_OP_CILOOKUP,	"CILOOKUP" }, \
> -	{ XFS_DA_OP_ALLOCVAL,	"ALLOCVAL" }
> +	{ XFS_DA_OP_ALLOCVAL,	"ALLOCVAL" }, \
> +	{ XFS_DA_OP_INCOMPLETE,	"INCOMPLETE" }
>  
>  /*
>   * Storage for holding state during Btree searches and split/join ops.
> diff --git a/fs/xfs/libxfs/xfs_da_format.h b/fs/xfs/libxfs/xfs_da_format.h
> index 3dee33043e09..05615d1f4113 100644
> --- a/fs/xfs/libxfs/xfs_da_format.h
> +++ b/fs/xfs/libxfs/xfs_da_format.h
> @@ -683,8 +683,6 @@ struct xfs_attr3_leafblock {
>  
>  /*
>   * Flags used in the leaf_entry[i].flags field.
> - * NOTE: the INCOMPLETE bit must not collide with the flags bits specified
> - * on the system call, they are "or"ed together for various operations.
>   */
>  #define	XFS_ATTR_LOCAL_BIT	0	/* attr is stored locally */
>  #define	XFS_ATTR_ROOT_BIT	1	/* limit access to trusted attrs */
> -- 
> 2.20.1
>