libvtreefs: API changes/extensions, part 2

- rename start_vtreefs to run_vtreefs, since the function returns upon
  termination these days;
- add get_inode_slots function to retrieve the number of indexed slots;
- add support for extra per-inode data for arbitrary storage.

Change-Id: If2d365d7b478a1cecc9e20fb2b3e70c1a1cf7243

minix/drivers/system/gpio/gpio.c

@@ -283,8 +283,8 @@ main(int argc, char **argv)
 	root_stat.size = 0;
 	root_stat.dev = NO_DEV;
 
-	/* limit the number of indexed entries */
-	start_vtreefs(&hooks, 30, &root_stat, 0, DATA_SIZE);
+	/* run VTreeFS */
+	run_vtreefs(&hooks, 30, 0, &root_stat, 0, DATA_SIZE);
 
 	return EXIT_SUCCESS;
 }

minix/fs/procfs/main.c

@@ -87,8 +87,9 @@ int main(void)
 	stat.size 	= 0;
 	stat.dev 	= NO_DEV;
 
-	/* Start VTreeFS. */
-	start_vtreefs(&hooks, NR_INODES, &stat, NR_PROCS + NR_TASKS, BUF_SIZE);
+	/* Run VTreeFS. */
+	run_vtreefs(&hooks, NR_INODES, 0, &stat, NR_PROCS + NR_TASKS,
+	    BUF_SIZE);
 
 	return 0;
 }

minix/include/minix/vtreefs.h

@@ -44,7 +44,7 @@ struct fs_hooks {
 
 extern struct inode *add_inode(struct inode *parent, const char *name,
 	index_t index, const struct inode_stat *stat,
-	index_t nr_indexed_entries, cbdata_t cbdata);
+	index_t nr_indexed_slots, cbdata_t cbdata);
 extern void delete_inode(struct inode *inode);
 
 extern struct inode *get_inode_by_name(const struct inode *parent,
@@ -54,7 +54,9 @@ extern struct inode *get_inode_by_index(const struct inode *parent,
 
 extern const char *get_inode_name(const struct inode *inode);
 extern index_t get_inode_index(const struct inode *inode);
+extern index_t get_inode_slots(const struct inode *inode);
 extern cbdata_t get_inode_cbdata(const struct inode *inode);
+extern void *get_inode_extra(const struct inode *inode);
 
 extern struct inode *get_root_inode(void);
 extern struct inode *get_parent_inode(const struct inode *inode);
@@ -64,7 +66,8 @@ extern struct inode *get_next_inode(const struct inode *previous);
 extern void get_inode_stat(const struct inode *inode, struct inode_stat *stat);
 extern void set_inode_stat(struct inode *inode, struct inode_stat *stat);
 
-extern void start_vtreefs(struct fs_hooks *hooks, unsigned int nr_inodes,
-	struct inode_stat *stat, index_t nr_indexed_entries, size_t buf_size);
+extern void run_vtreefs(struct fs_hooks *hooks, unsigned int nr_inodes,
+	size_t inode_extra, struct inode_stat *stat, index_t nr_indexed_slots,
+	size_t buf_size);
 
 #endif /* _MINIX_VTREEFS_H */

minix/lib/libvtreefs/Makefile

@@ -7,6 +7,7 @@ CPPFLAGS+= -D_MINIX_SYSTEM
 LIB=	vtreefs
 
 SRCS=	\
+	extra.c \
 	file.c \
 	inode.c \
 	link.c \

minix/lib/libvtreefs/extra.c

@@ -0,0 +1,56 @@
+/* VTreeFS - extra.c - per-inode storage of arbitrary extra data */
+
+#include "inc.h"
+
+/*
+ * Right now, we maintain the extra data (if requested) as a separate buffer,
+ * so that we don't have to make the inode structure variable in size.  Later,
+ * if for example the maximum node name length becomes a runtime setting, we
+ * could reconsider this.
+ */
+static char *extra_ptr = NULL;
+static size_t extra_size = 0; /* per inode */
+
+/*
+ * Initialize memory to store extra data.
+ */
+int
+init_extra(unsigned int nr_inodes, size_t inode_extra)
+{
+
+	if (extra_size == 0)
+		return OK;
+
+	if ((extra_ptr = malloc(nr_inodes * inode_extra)) == NULL)
+		return ENOMEM;
+
+	extra_size = inode_extra;
+
+	return OK;
+}
+
+/*
+ * Initialize the extra data for the given inode to zero.
+ */
+void
+clear_inode_extra(struct inode * node)
+{
+
+	if (extra_size == 0)
+		return;
+
+	memset(&extra_ptr[node->i_num * extra_size], 0, extra_size);
+}
+
+/*
+ * Retrieve a pointer to the extra data for the given inode.
+ */
+void *
+get_inode_extra(const struct inode * node)
+{
+
+	if (extra_size == 0)
+		return NULL;
+
+	return (void *)&extra_ptr[node->i_num * extra_size];
+}

minix/lib/libvtreefs/inode.c

@@ -19,6 +19,7 @@ static LIST_HEAD(index_head, inode) *parent_index_head;
 #define CHECK_INODE(node)						\
 	do {								\
 		assert(node >= &inode[0] && node < &inode[nr_inodes]);	\
+		assert((unsigned int)(node - &inode[0]) == node->i_num);\
 		assert(node == &inode[0] || node->i_parent != NULL ||	\
 		    (node->i_flags & I_DELETED));			\
 	} while (0);
@@ -68,7 +69,7 @@ init_inodes(unsigned int inodes, struct inode_stat * stat,
 	/* Add free inodes to the unused/free list.  Skip the root inode. */
 	for (i = 1; i < nr_inodes; i++) {
 		node = &inode[i];
-
+		node->i_num = i;
 		node->i_parent = NULL;
 		node->i_count = 0;
 		TAILQ_INIT(&node->i_children);
@@ -83,6 +84,7 @@ init_inodes(unsigned int inodes, struct inode_stat * stat,
 
 	/* Initialize the root inode. */
 	node = &inode[0];
+	node->i_num = 0;
 	node->i_parent = NULL;
 	node->i_count = 0;
 	TAILQ_INIT(&node->i_children);
@@ -114,15 +116,13 @@ cleanup_inodes(void)
 static int
 parent_name_hash(const struct inode * parent, const char *name)
 {
-	unsigned int name_hash, parent_hash;
-
-	/* The parent hash is a simple array entry; find its index. */
-	parent_hash = (unsigned int)(parent - &inode[0]);
+	unsigned int name_hash;
 
 	/* Use the sdbm algorithm to hash the name. */
 	name_hash = sdbm_hash(name, strlen(name));
 
-	return (parent_hash ^ name_hash) % nr_inodes;
+	/* The parent hash is a simple array entry. */
+	return (parent->i_num ^ name_hash) % nr_inodes;
 }
 
 /*
@@ -132,7 +132,7 @@ static int
 parent_index_hash(const struct inode * parent, index_t index)
 {
 
-	return ((int)(parent - &inode[0]) ^ index) % nr_inodes;
+	return (parent->i_num ^ index) % nr_inodes;
 }
 
 /*
@@ -217,6 +217,9 @@ add_inode(struct inode * parent, const char * name, index_t index,
 	newnode->i_cbdata = cbdata;
 	strlcpy(newnode->i_name, name, sizeof(newnode->i_name));
 
+	/* Clear the extra data for this inode, if present. */
+	clear_inode_extra(newnode);
+
 	/* Add the inode to the list of children inodes of the parent. */
 	TAILQ_INSERT_HEAD(&parent->i_children, newnode, i_siblings);
 
@@ -268,6 +271,18 @@ get_inode_index(const struct inode * node)
 	return node->i_index;
 }
 
+/*
+ * Return the number of indexed slots for the given (directory) inode.
+ */
+index_t
+get_inode_slots(const struct inode * node)
+{
+
+	CHECK_INODE(node);
+
+	return node->i_indexed;
+}
+
 /*
  * Return the callback data associated with the given inode.
  */
@@ -342,7 +357,7 @@ get_inode_number(const struct inode * node)
 
 	CHECK_INODE(node);
 
-	return (int)(node - &inode[0]) + 1;
+	return node->i_num + 1;
 }
 
 /*

minix/lib/libvtreefs/inode.h

@@ -16,6 +16,10 @@
  * unused inodes.
  */
 struct inode {
+	/* Inode identity */
+	unsigned int i_num;		/* index number into the inode array */
+	/* Note that the actual inode number (of type ino_t) is (i_num + 1). */
+
 	/* Inode metadata */
 	struct inode_stat i_stat;	/* POSIX attributes */
 	char i_name[PNAME_MAX + 1];	/* name of the inode in the parent */

minix/lib/libvtreefs/proto.h

@@ -1,6 +1,10 @@
 #ifndef _VTREEFS_PROTO_H
 #define _VTREEFS_PROTO_H
 
+/* extra.c */
+int init_extra(unsigned int inodes, size_t inode_extra);
+void clear_inode_extra(struct inode *node);
+
 /* file.c */
 int init_buf(size_t size);
 void cleanup_buf(void);

minix/lib/libvtreefs/vtreefs.c

@@ -6,6 +6,7 @@ static unsigned int inodes;
 static struct inode_stat *root_stat;
 static index_t root_entries;
 static size_t buf_size;
+static size_t extra_size;
 
 /*
  * Initialize internal state.  This is the only place where dynamic memory
@@ -20,6 +21,10 @@ init_server(int __unused type, sef_init_info_t * __unused info)
 	if ((r = init_inodes(inodes, root_stat, root_entries)) != OK)
 		panic("init_inodes failed: %d", r);
 
+	/* Initialize extra data. */
+	if ((r = init_extra(inodes, extra_size)) != OK)
+		panic("init_extra failed: %d", r);
+
 	/* Initialize the I/O buffer. */
 	if ((r = init_buf(buf_size)) != OK)
 		panic("init_buf failed: %d", r);
@@ -83,8 +88,9 @@ fs_other(const message * m_ptr, int ipc_status)
  * unmounted and the process is signaled to exit.
  */
 void
-start_vtreefs(struct fs_hooks * hooks, unsigned int nr_inodes,
-	struct inode_stat * stat, index_t nr_indexed_entries, size_t bufsize)
+run_vtreefs(struct fs_hooks * hooks, unsigned int nr_inodes,
+	size_t inode_extra, struct inode_stat * stat,
+	index_t nr_indexed_entries, size_t bufsize)
 {
 
 	/*
@@ -93,6 +99,7 @@ start_vtreefs(struct fs_hooks * hooks, unsigned int nr_inodes,
 	 */
 	vtreefs_hooks = hooks;
 	inodes = nr_inodes;
+	extra_size = inode_extra;
 	root_stat = stat;
 	root_entries = nr_indexed_entries;
 	buf_size = bufsize;

minix/servers/devman/main.c

@@ -85,8 +85,9 @@ int main (int argc, char* argv[])
 	root_stat.size 	= 0;
 	root_stat.dev 	= NO_DEV;
 
-	/* limit the number of indexed entries */
-	start_vtreefs(&hooks, 1024, &root_stat, 0, BUF_SIZE);
+	/* run VTreeFS */
+	run_vtreefs(&hooks, 1024, 0, &root_stat, 0, BUF_SIZE);
+
 	return 0;
 }