xfs: remove ATTR_KERNOVAL

We can just pass down the Linux convention of a zero valuelen to just
query for the existance of an attribute to the low-level code instead.
The use in the legacy xfs_attr_list code only used by the ioctl
interface was already dead code, as the callers check that the flag
is not present.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Chandan Rajendra <chandanrlinux@gmail.com>
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

@@ -94,9 +94,9 @@ xfs_attr_get_ilocked(
 /*
  * Retrieve an extended attribute by name, and its value if requested.
  *
- * If ATTR_KERNOVAL is set in args->flags, then the caller does not want the
- * value, just an indication whether the attribute exists and the size of the
- * value if it exists. The size is returned in args.valuelen.
+ * If args->valuelen is zero, then the caller does not want the value, just an
+ * indication whether the attribute exists and the size of the value if it
+ * exists. The size is returned in args.valuelen.
  *
  * If the attribute is found, but exceeds the size limit set by the caller in
  * args->valuelen, return -ERANGE with the size of the attribute that was found
@@ -115,7 +115,7 @@ xfs_attr_get(
 	uint			lock_mode;
 	int			error;
 
-	ASSERT((args->flags & (ATTR_ALLOC | ATTR_KERNOVAL)) || args->value);
+	ASSERT((args->flags & ATTR_ALLOC) || !args->valuelen || args->value);
 
 	XFS_STATS_INC(args->dp->i_mount, xs_attr_get);
 

fs/xfs/libxfs/xfs_attr.h

@@ -34,12 +34,11 @@ struct xfs_attr_list_context;
 #define ATTR_REPLACE	0x0020	/* pure set: fail if attr does not exist */
 
 #define ATTR_KERNOTIME	0x1000	/* [kernel] don't update inode timestamps */
-#define ATTR_KERNOVAL	0x2000	/* [kernel] get attr size only, not value */
 
 #define ATTR_ALLOC	0x8000	/* [kernel] allocate xattr buffer on demand */
 
 #define ATTR_KERNEL_FLAGS \
-	(ATTR_KERNOTIME | ATTR_KERNOVAL | ATTR_ALLOC)
+	(ATTR_KERNOTIME | ATTR_ALLOC)
 
 #define XFS_ATTR_FLAGS \
 	{ ATTR_DONTFOLLOW, 	"DONTFOLLOW" }, \
@@ -49,7 +48,6 @@ struct xfs_attr_list_context;
 	{ ATTR_CREATE,		"CREATE" }, \
 	{ ATTR_REPLACE,		"REPLACE" }, \
 	{ ATTR_KERNOTIME,	"KERNOTIME" }, \
-	{ ATTR_KERNOVAL,	"KERNOVAL" }, \
 	{ ATTR_ALLOC,		"ALLOC" }
 
 /*

fs/xfs/libxfs/xfs_attr_leaf.c

@@ -464,7 +464,7 @@ xfs_attr_copy_value(
 	/*
 	 * No copy if all we have to do is get the length
 	 */
-	if (args->flags & ATTR_KERNOVAL) {
+	if (!args->valuelen) {
 		args->valuelen = valuelen;
 		return 0;
 	}
@@ -830,9 +830,9 @@ xfs_attr_shortform_lookup(xfs_da_args_t *args)
 /*
  * Retrieve the attribute value and length.
  *
- * If ATTR_KERNOVAL is specified, only the length needs to be returned.
- * Unlike a lookup, we only return an error if the attribute does not
- * exist or we can't retrieve the value.
+ * If args->valuelen is zero, only the length needs to be returned.  Unlike a
+ * lookup, we only return an error if the attribute does not exist or we can't
+ * retrieve the value.
  */
 int
 xfs_attr_shortform_getvalue(
@@ -2444,9 +2444,9 @@ xfs_attr3_leaf_lookup_int(
  * Get the value associated with an attribute name from a leaf attribute
  * list structure.
  *
- * If ATTR_KERNOVAL is specified, only the length needs to be returned.
- * Unlike a lookup, we only return an error if the attribute does not
- * exist or we can't retrieve the value.
+ * If args->valuelen is zero, only the length needs to be returned.  Unlike a
+ * lookup, we only return an error if the attribute does not exist or we can't
+ * retrieve the value.
  */
 int
 xfs_attr3_leaf_getvalue(

fs/xfs/libxfs/xfs_attr_remote.c

@@ -397,7 +397,7 @@ xfs_attr_rmtval_get(
 
 	trace_xfs_attr_rmtval_get(args);
 
-	ASSERT(!(args->flags & ATTR_KERNOVAL));
+	ASSERT(args->valuelen != 0);
 	ASSERT(args->rmtvaluelen == args->valuelen);
 
 	valuelen = args->rmtvaluelen;

fs/xfs/xfs_attr_list.c

@@ -568,7 +568,6 @@ xfs_attr_put_listent(
 	int arraytop;
 
 	ASSERT(!context->seen_enough);
-	ASSERT(!(context->flags & ATTR_KERNOVAL));
 	ASSERT(context->count >= 0);
 	ASSERT(context->count < (ATTR_MAX_VALUELEN/8));
 	ASSERT(context->firstu >= sizeof(*alist));
@@ -637,8 +636,6 @@ xfs_attr_list(
 	 */
 	if (((long)buffer) & (sizeof(int)-1))
 		return -EFAULT;
-	if (flags & ATTR_KERNOVAL)
-		bufsize = 0;
 
 	/*
 	 * Initialize the output buffer.

fs/xfs/xfs_xattr.c

@@ -33,10 +33,6 @@ xfs_xattr_get(const struct xattr_handler *handler, struct dentry *unused,
 	};
 	int			error;
 
-	/* Convert Linux syscall to XFS internal ATTR flags */
-	if (!size)
-		args.flags |= ATTR_KERNOVAL;
-
 	error = xfs_attr_get(&args);
 	if (error)
 		return error;