xfs: Add xfs_has_attr and subroutines

This patch adds a new functions to check for the existence of an
attribute. Subroutines are also added to handle the cases of leaf
blocks, nodes or shortform. Common code that appears in existing attr
add and remove functions have been factored out to help reduce the
appearance of duplicated code.  We will need these routines later for
delayed attributes since delayed operations cannot return error codes.

Signed-off-by: Allison Collins <[email protected]>
Reviewed-by: Chandan Rajendra <[email protected]>
Reviewed-by: Brian Foster <[email protected]>
Reviewed-by: Darrick J. Wong <[email protected]>
[darrick: fix a leak-on-error bug reported by Dan Carpenter]
[darrick: fix unused variable warning reported by 0day]
Signed-off-by: Darrick J. Wong <[email protected]>
Acked-by: Dave Chinner <[email protected]>
Reported-by: [email protected]
Reported-by: kernel test robot <[email protected]>

Author: allisonhenderson

fs/xfs/libxfs/xfs_attr.c

@@ -46,13 +46,16 @@ STATIC int xfs_attr_shortform_addname(xfs_da_args_t *args);
 STATIC int xfs_attr_leaf_get(xfs_da_args_t *args);
 STATIC int xfs_attr_leaf_addname(xfs_da_args_t *args);
 STATIC int xfs_attr_leaf_removename(xfs_da_args_t *args);
+STATIC int xfs_attr_leaf_hasname(struct xfs_da_args *args, struct xfs_buf **bp);
 
 /*
  * Internal routines when attribute list is more than one block.
  */
 STATIC int xfs_attr_node_get(xfs_da_args_t *args);
 STATIC int xfs_attr_node_addname(xfs_da_args_t *args);
 STATIC int xfs_attr_node_removename(xfs_da_args_t *args);
+STATIC int xfs_attr_node_hasname(xfs_da_args_t *args,
+				 struct xfs_da_state **state);
 STATIC int xfs_attr_fillstate(xfs_da_state_t *state);
 STATIC int xfs_attr_refillstate(xfs_da_state_t *state);
 
@@ -260,6 +263,37 @@ xfs_attr_set_args(
 	return error;
 }
 
+/*
+ * Return EEXIST if attr is found, or ENOATTR if not
+ */
+int
+xfs_has_attr(
+	struct xfs_da_args	*args)
+{
+	struct xfs_inode	*dp = args->dp;
+	struct xfs_buf		*bp = NULL;
+	int			error;
+
+	if (!xfs_inode_hasattr(dp))
+		return -ENOATTR;
+
+	if (dp->i_afp->if_format == XFS_DINODE_FMT_LOCAL) {
+		ASSERT(dp->i_afp->if_flags & XFS_IFINLINE);
+		return xfs_attr_sf_findname(args, NULL, NULL);
+	}
+
+	if (xfs_bmap_one_block(dp, XFS_ATTR_FORK)) {
+		error = xfs_attr_leaf_hasname(args, &bp);
+
+		if (bp)
+			xfs_trans_brelse(args->trans, bp);
+
+		return error;
+	}
+
+	return xfs_attr_node_hasname(args, NULL);
+}
+
 /*
  * Remove the attribute specified in @args.
  */
@@ -469,26 +503,19 @@ STATIC int
 xfs_attr_leaf_addname(
 	struct xfs_da_args	*args)
 {
-	struct xfs_inode	*dp;
 	struct xfs_buf		*bp;
 	int			retval, error, forkoff;
+	struct xfs_inode	*dp = args->dp;
 
 	trace_xfs_attr_leaf_addname(args);
 
-	/*
-	 * Read the (only) block in the attribute list in.
-	 */
-	dp = args->dp;
-	args->blkno = 0;
-	error = xfs_attr3_leaf_read(args->trans, args->dp, args->blkno, &bp);
-	if (error)
-		return error;
-
 	/*
 	 * Look up the given attribute in the leaf block.  Figure out if
 	 * the given flags produce an error or call for an atomic rename.
 	 */
-	retval = xfs_attr3_leaf_lookup_int(bp, args);
+	retval = xfs_attr_leaf_hasname(args, &bp);
+	if (retval != -ENOATTR && retval != -EEXIST)
+		return retval;
 	if (retval == -ENOATTR && (args->attr_flags & XATTR_REPLACE))
 		goto out_brelse;
 	if (retval == -EEXIST) {
@@ -639,6 +666,27 @@ xfs_attr_leaf_addname(
 	return retval;
 }
 
+/*
+ * Return EEXIST if attr is found, or ENOATTR if not
+ */
+STATIC int
+xfs_attr_leaf_hasname(
+	struct xfs_da_args	*args,
+	struct xfs_buf		**bp)
+{
+	int                     error = 0;
+
+	error = xfs_attr3_leaf_read(args->trans, args->dp, 0, bp);
+	if (error)
+		return error;
+
+	error = xfs_attr3_leaf_lookup_int(*bp, args);
+	if (error != -ENOATTR && error != -EEXIST)
+		xfs_trans_brelse(args->trans, *bp);
+
+	return error;
+}
+
 /*
  * Remove a name from the leaf attribute list structure
  *
@@ -659,16 +707,14 @@ xfs_attr_leaf_removename(
 	 * Remove the attribute.
 	 */
 	dp = args->dp;
-	args->blkno = 0;
-	error = xfs_attr3_leaf_read(args->trans, args->dp, args->blkno, &bp);
-	if (error)
-		return error;
 
-	error = xfs_attr3_leaf_lookup_int(bp, args);
+	error = xfs_attr_leaf_hasname(args, &bp);
+
 	if (error == -ENOATTR) {
 		xfs_trans_brelse(args->trans, bp);
 		return error;
-	}
+	} else if (error != -EEXIST)
+		return error;
 
 	xfs_attr3_leaf_remove(bp, args);
 
@@ -703,21 +749,53 @@ xfs_attr_leaf_get(xfs_da_args_t *args)
 
 	trace_xfs_attr_leaf_get(args);
 
-	args->blkno = 0;
-	error = xfs_attr3_leaf_read(args->trans, args->dp, args->blkno, &bp);
-	if (error)
-		return error;
+	error = xfs_attr_leaf_hasname(args, &bp);
 
-	error = xfs_attr3_leaf_lookup_int(bp, args);
-	if (error != -EEXIST)  {
+	if (error == -ENOATTR)  {
 		xfs_trans_brelse(args->trans, bp);
 		return error;
-	}
+	} else if (error != -EEXIST)
+		return error;
+
+
 	error = xfs_attr3_leaf_getvalue(bp, args);
 	xfs_trans_brelse(args->trans, bp);
 	return error;
 }
 
+/*
+ * Return EEXIST if attr is found, or ENOATTR if not
+ * statep: If not null is set to point at the found state.  Caller will
+ *         be responsible for freeing the state in this case.
+ */
+STATIC int
+xfs_attr_node_hasname(
+	struct xfs_da_args	*args,
+	struct xfs_da_state	**statep)
+{
+	struct xfs_da_state	*state;
+	int			retval, error;
+
+	state = xfs_da_state_alloc(args);
+	if (statep != NULL)
+		*statep = NULL;
+
+	/*
+	 * Search to see if name exists, and get back a pointer to it.
+	 */
+	error = xfs_da3_node_lookup_int(state, &retval);
+	if (error) {
+		xfs_da_state_free(state);
+		return error;
+	}
+
+	if (statep != NULL)
+		*statep = state;
+	else
+		xfs_da_state_free(state);
+	return retval;
+}
+
 /*========================================================================
  * External routines when attribute list size > geo->blksize
  *========================================================================*/
@@ -748,15 +826,14 @@ xfs_attr_node_addname(
 	 */
 	dp = args->dp;
 restart:
-	state = xfs_da_state_alloc(args);
-
 	/*
 	 * Search to see if name already exists, and get back a pointer
 	 * to where it should go.
 	 */
-	error = xfs_da3_node_lookup_int(state, &retval);
-	if (error)
+	retval = xfs_attr_node_hasname(args, &state);
+	if (retval != -ENOATTR && retval != -EEXIST)
 		goto out;
+
 	blk = &state->path.blk[ state->path.active-1 ];
 	ASSERT(blk->magic == XFS_ATTR_LEAF_MAGIC);
 	if (retval == -ENOATTR && (args->attr_flags & XATTR_REPLACE))
@@ -960,27 +1037,15 @@ xfs_attr_node_removename(
 {
 	struct xfs_da_state	*state;
 	struct xfs_da_state_blk	*blk;
-	struct xfs_inode	*dp;
 	struct xfs_buf		*bp;
 	int			retval, error, forkoff;
+	struct xfs_inode	*dp = args->dp;
 
 	trace_xfs_attr_node_removename(args);
 
-	/*
-	 * Tie a string around our finger to remind us where we are.
-	 */
-	dp = args->dp;
-	state = xfs_da_state_alloc(args);
-
-	/*
-	 * Search to see if name exists, and get back a pointer to it.
-	 */
-	error = xfs_da3_node_lookup_int(state, &retval);
-	if (error || (retval != -EEXIST)) {
-		if (error == 0)
-			error = retval;
+	error = xfs_attr_node_hasname(args, &state);
+	if (error != -EEXIST)
 		goto out;
-	}
 
 	/*
 	 * If there is an out-of-line value, de-allocate the blocks.
@@ -1075,7 +1140,8 @@ xfs_attr_node_removename(
 	error = 0;
 
 out:
-	xfs_da_state_free(state);
+	if (state)
+		xfs_da_state_free(state);
 	return error;
 }
 
@@ -1191,45 +1257,41 @@ xfs_attr_refillstate(xfs_da_state_t *state)
  * Returns 0 on successful retrieval, otherwise an error.
  */
 STATIC int
-xfs_attr_node_get(xfs_da_args_t *args)
+xfs_attr_node_get(
+	struct xfs_da_args	*args)
 {
-	xfs_da_state_t *state;
-	xfs_da_state_blk_t *blk;
-	int error, retval;
-	int i;
+	struct xfs_da_state	*state;
+	struct xfs_da_state_blk	*blk;
+	int			i;
+	int			error;
 
 	trace_xfs_attr_node_get(args);
 
-	state = xfs_da_state_alloc(args);
-
 	/*
 	 * Search to see if name exists, and get back a pointer to it.
 	 */
-	error = xfs_da3_node_lookup_int(state, &retval);
-	if (error) {
-		retval = error;
-		goto out_release;
-	}
-	if (retval != -EEXIST)
+	error = xfs_attr_node_hasname(args, &state);
+	if (error != -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);
+	error = 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++) {
+	for (i = 0; state != NULL && i < state->path.active; i++) {
 		xfs_trans_brelse(args->trans, state->path.blk[i].bp);
 		state->path.blk[i].bp = NULL;
 	}
 
-	xfs_da_state_free(state);
-	return retval;
+	if (state)
+		xfs_da_state_free(state);
+	return error;
 }
 
 /* Returns true if the attribute entry name is valid. */

fs/xfs/libxfs/xfs_attr.h

@@ -89,6 +89,7 @@ int xfs_attr_get_ilocked(struct xfs_da_args *args);
 int xfs_attr_get(struct xfs_da_args *args);
 int xfs_attr_set(struct xfs_da_args *args);
 int xfs_attr_set_args(struct xfs_da_args *args);
+int xfs_has_attr(struct xfs_da_args *args);
 int xfs_attr_remove_args(struct xfs_da_args *args);
 bool xfs_attr_namecheck(const void *name, size_t length);