Add inodes-since command

The kernel now has an ioctl to give us inode numbers with their sequence
number for every inode that's been modified since a given tree update
sequence number.

Update mkfs and print to the on-disk format changes and add a trivial
inodes-since command which calls the ioctl and prints the results.

Signed-off-by: Zach Brown <zab@versity.com>

utils/src/format.h

@@ -91,9 +91,14 @@ struct scoutfs_btree_block {
 	__le16 nr_items;
 } __packed;
 
+/*
+ * The item sequence number is set to the dirty block's sequence number
+ * when the item is modified.  It is not changed by splits or merges.
+ */
 struct scoutfs_btree_item {
 	struct scoutfs_key key;
 	struct scoutfs_treap_node tnode;
+	__le64 seq;
 	__le16 val_len;
 	char val[0];
 } __packed;

utils/src/ioctl.h

@@ -27,4 +27,23 @@ struct scoutfs_trace_record {
 #define SCOUTFS_IOC_GET_TRACE_RECORDS _IOW(SCOUTFS_IOCTL_MAGIC, 2, \
 					   struct scoutfs_ioctl_buf)
 
+struct scoutfs_ioctl_ino_seq {
+	__u64 ino;
+	__u64 seq;
+} __packed;
+
+struct scoutfs_ioctl_inodes_since {
+	__u64 first_ino;
+	__u64 last_ino;
+	__u64 seq;
+	struct scoutfs_ioctl_buf results;
+} __packed;
+
+/*
+ * Adds entries to the user's buffer for each inode whose sequence
+ * number is greater than or equal to the given seq.
+ */
+#define SCOUTFS_IOC_INODES_SINCE _IOW(SCOUTFS_IOCTL_MAGIC, 3, \
+				      struct scoutfs_ioctl_inodes_since)
+
 #endif

utils/src/mkfs.c

@@ -125,6 +125,7 @@ static int write_new_fs(char *path, int fd)
 	bt->nr_items = cpu_to_le16(1);
 
 	item = (void *)(bt + 1);
+	item->seq = cpu_to_le64(1);
 	item->key = root_key;
 	item->tnode.parent = 0;
 	item->tnode.left = 0;

utils/src/print.c

@@ -99,9 +99,10 @@ static void print_block_ref(struct scoutfs_block_ref *ref)
 static void print_btree_item(unsigned int off, struct scoutfs_btree_item *item,
 			     u8 level)
 {
-	printf("    item: key "SKF" val_len %u off %u tnode: parent %u left %u right %u "
+	printf("    item: key "SKF" seq %llu val_len %u off %u tnode: parent %u left %u right %u "
 	       "prio %x\n",
-		SKA(&item->key), le16_to_cpu(item->val_len), off,
+		SKA(&item->key), le64_to_cpu(item->seq),
+		le16_to_cpu(item->val_len), off,
 		le16_to_cpu(item->tnode.parent),
 		le16_to_cpu(item->tnode.left),
 		le16_to_cpu(item->tnode.right),

utils/src/since.c

@@ -0,0 +1,89 @@
+#include <unistd.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/ioctl.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <string.h>
+#include <limits.h>
+
+#include "sparse.h"
+#include "util.h"
+#include "ioctl.h"
+#include "cmd.h"
+
+static int since_cmd(int argc, char **argv)
+{
+	struct scoutfs_ioctl_inodes_since args;
+	struct scoutfs_ioctl_ino_seq *iseq;
+	int len = 4 * 1024 * 1024;
+	char *endptr;
+	u64 nrs[3];
+	void *ptr;
+	int ret;
+	int fd;
+	u64 n;
+	int i;
+
+	if (argc != 4) {
+		fprintf(stderr, "must specify seq and path\n");
+		return -EINVAL;
+	}
+
+	for (i = 0; i < array_size(nrs); i++) {
+		n = strtoull(argv[i], &endptr, 0);
+		if (*endptr != '\0' ||
+		    ((n == LLONG_MIN || n == LLONG_MAX) && errno == ERANGE)) {
+			fprintf(stderr, "error parsing 64bit value '%s'\n",
+			        argv[i]);
+			return -EINVAL;
+		}
+		nrs[i] = n;
+	}
+
+	fd = open(argv[3], O_RDONLY);
+	if (fd < 0) {
+		ret = -errno;
+		fprintf(stderr, "failed to open '%s': %s (%d)\n",
+			argv[3], strerror(errno), errno);
+		return ret;
+	}
+
+	ptr = malloc(len);
+	if (!ptr) {
+		fprintf(stderr, "must specify seq and path\n");
+		close(fd);
+		return -EINVAL;
+	}
+
+	args.first_ino = nrs[0];
+	args.last_ino = nrs[1];
+	args.seq = nrs[2];
+	args.results.ptr = (intptr_t)ptr;
+	args.results.len = len;
+
+	ret = ioctl(fd, SCOUTFS_IOC_INODES_SINCE, &args);
+	if (ret < 0) {
+		ret = -errno;
+		fprintf(stderr, "inodes_since ioctl failed: %s (%d)\n",
+			strerror(errno), errno);
+		goto out;
+	}
+
+	n = ret / sizeof(*iseq);
+	for (i = 0, iseq = ptr; i < n; i++, iseq++)
+		printf("ino %llu seq %llu\n", iseq->ino, iseq->seq);
+
+out:
+	free(ptr);
+	close(fd);
+	return ret;
+};
+
+static void __attribute__((constructor)) since_ctor(void)
+{
+	cmd_register("inodes-since", "<first> <last> <seq> <path>",
+		     "print inodes modified since seq #", since_cmd);
+}