xfs: fix misuse of the XFS_ATTR_INCOMPLETE flag

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

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;

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) {

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.

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 */