1 files changed, 55 insertions, 24 deletions

diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
index d48fcf11cc35..510ca6974604 100644
--- a/fs/xfs/libxfs/xfs_attr.c
+++ b/fs/xfs/libxfs/xfs_attr.c
@@ -97,7 +97,10 @@ xfs_inode_hasattr(
  * Overall external interface routines.
  *========================================================================*/
 
-/* Retrieve an extended attribute and its value.  Must have ilock. */
+/*
+ * Retrieve an extended attribute and its value.  Must have ilock.
+ * Returns 0 on successful retrieval, otherwise an error.
+ */
 int
 xfs_attr_get_ilocked(
 	struct xfs_inode	*ip,
@@ -115,12 +118,28 @@ xfs_attr_get_ilocked(
 		return xfs_attr_node_get(args);
 }
 
-/* Retrieve an extended attribute by name, and its value. */
+/*
+ * Retrieve an extended attribute by name, and its value if requested.
+ *
+ * If ATTR_KERNOVAL is set in @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 @valuelenp,
+ *
+ * If the attribute is found, but exceeds the size limit set by the caller in
+ * @valuelenp, return -ERANGE with the size of the attribute that was found in
+ * @valuelenp.
+ *
+ * If ATTR_ALLOC is set in @flags, allocate the buffer for the value after
+ * existence of the attribute has been determined. On success, return that
+ * buffer to the caller and leave them to free it. On failure, free any
+ * allocated buffer and ensure the buffer pointer returned to the caller is
+ * null.
+ */
 int
 xfs_attr_get(
 	struct xfs_inode	*ip,
 	const unsigned char	*name,
-	unsigned char		*value,
+	unsigned char		**value,
 	int			*valuelenp,
 	int			flags)
 {
@@ -128,6 +147,8 @@ xfs_attr_get(
 	uint			lock_mode;
 	int			error;
 
+	ASSERT((flags & (ATTR_ALLOC | ATTR_KERNOVAL)) || *value);
+
 	XFS_STATS_INC(ip->i_mount, xs_attr_get);
 
 	if (XFS_FORCED_SHUTDOWN(ip->i_mount))
@@ -137,17 +158,29 @@ xfs_attr_get(
 	if (error)
 		return error;
 
-	args.value = value;
-	args.valuelen = *valuelenp;
 	/* Entirely possible to look up a name which doesn't exist */
 	args.op_flags = XFS_DA_OP_OKNOENT;
+	if (flags & ATTR_ALLOC)
+		args.op_flags |= XFS_DA_OP_ALLOCVAL;
+	else
+		args.value = *value;
+	args.valuelen = *valuelenp;
 
 	lock_mode = xfs_ilock_attr_map_shared(ip);
 	error = xfs_attr_get_ilocked(ip, &args);
 	xfs_iunlock(ip, lock_mode);
-
 	*valuelenp = args.valuelen;
-	return error == -EEXIST ? 0 : error;
+
+	/* on error, we have to clean up allocated value buffers */
+	if (error) {
+		if (flags & ATTR_ALLOC) {
+			kmem_free(args.value);
+			*value = NULL;
+		}
+		return error;
+	}
+	*value = args.value;
+	return 0;
 }
 
 /*
@@ -768,6 +801,8 @@ xfs_attr_leaf_removename(
  *
  * This leaf block cannot have a "remote" value, we only call this routine
  * if bmap_one_block() says there is only one block (ie: no remote blks).
+ *
+ * Returns 0 on successful retrieval, otherwise an error.
  */
 STATIC int
 xfs_attr_leaf_get(xfs_da_args_t *args)
@@ -789,9 +824,6 @@ xfs_attr_leaf_get(xfs_da_args_t *args)
 	}
 	error = xfs_attr3_leaf_getvalue(bp, args);
 	xfs_trans_brelse(args->trans, bp);
-	if (!error && (args->rmtblkno > 0) && !(args->flags & ATTR_KERNOVAL)) {
-		error = xfs_attr_rmtval_get(args);
-	}
 	return error;
 }
 
@@ -1268,11 +1300,13 @@ xfs_attr_refillstate(xfs_da_state_t *state)
 }
 
 /*
- * Look up a filename in a node attribute list.
+ * Retrieve the attribute data from a node attribute list.
  *
  * This routine gets called for any attribute fork that has more than one
  * block, ie: both true Btree attr lists and for single-leaf-blocks with
  * "remote" values taking up more blocks.
+ *
+ * Returns 0 on successful retrieval, otherwise an error.
  */
 STATIC int
 xfs_attr_node_get(xfs_da_args_t *args)
@@ -1294,24 +1328,21 @@ xfs_attr_node_get(xfs_da_args_t *args)
 	error = xfs_da3_node_lookup_int(state, &retval);
 	if (error) {
 		retval = error;
-	} else if (retval == -EEXIST) {
-		blk = &state->path.blk[ state->path.active-1 ];
-		ASSERT(blk->bp != NULL);
-		ASSERT(blk->magic == XFS_ATTR_LEAF_MAGIC);
-
-		/*
-		 * Get the value, local or "remote"
-		 */
-		retval = xfs_attr3_leaf_getvalue(blk->bp, args);
-		if (!retval && (args->rmtblkno > 0)
-		    && !(args->flags & ATTR_KERNOVAL)) {
-			retval = xfs_attr_rmtval_get(args);
-		}
+		goto out_release;
 	}
+	if (retval != -EEXIST)
+		goto out_release;
+
+	/*
+	 * Get the value, local or "remote"
+	 */
+	blk = &state->path.blk[state->path.active - 1];
+	retval = xfs_attr3_leaf_getvalue(blk->bp, args);
 
 	/*
 	 * If not in a transaction, we have to release all the buffers.
 	 */
+out_release:
 	for (i = 0; i < state->path.active; i++) {
 		xfs_trans_brelse(args->trans, state->path.blk[i].bp);
 		state->path.blk[i].bp = NULL;