[PATCH] xfs_io: implement 'inode' command V5

[Carlos Maiolino]

Implements a new xfs_io command, named 'inode', which is supposed to be
used to query information about inode's existence and its physical size
in the filesystem.

Supported options:

Default:     -- Return true(1) or false(0) if any inode greater than
                32bits has been found in the filesystem
-v           -- verbose mode
                Display the number and the physical size (in bits)
                of the largest inode in the filesystem
[num]        -- Return true(1) or false(0) if the inode [num] is in use
-n [num]     -- Return the next valid inode after [num]

No manpage sent because there were changes in the supported options and its
descriptions.
I'll send the manpage after the options and descriptions are reviewed.

- Changelog

V3:
	- Merge all 3 patches from the V2 together in a single patch
	- Rework of '-n [num]' and 'num' only arguments algorithm
	- Argument -n now relies on bulkreq.count to check for next inodes, not
	  on bstat.bs_ino anymore.
	- for loop in ret_lsize or ret_largest case, now relies on count being 0
	  to break the loop

V4:
	- Refactor inode_f function to reduce its size and easier logic
	- Implement error handlers for invalid command combination (hopefully
	  all invalid combinations).
	- use a single xfs_inogrp array for keep track of inodes
	- Fix missing newline in inode_help()
	- Rewrite help message in inode_help()
	- Fix indentation

V5:
	- Reduce the amount of options
	- remove igrp_rec variable, and use igroup[lastgrp] directly to get
	  information from the last inode groups returned by ioctl

Signed-off-by: Carlos Maiolino <cmaiolino at redhat.com>
---
 io/open.c | 143 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 143 insertions(+)

diff --git a/io/open.c b/io/open.c
index ac5a5e0..1e38ea8 100644
--- a/io/open.c
+++ b/io/open.c
@@ -20,6 +20,7 @@
 #include "input.h"
 #include "init.h"
 #include "io.h"
+#include "libxfs.h"
 
 #ifndef __O_TMPFILE
 #if defined __alpha__
@@ -44,6 +45,7 @@ static cmdinfo_t statfs_cmd;
 static cmdinfo_t chproj_cmd;
 static cmdinfo_t lsproj_cmd;
 static cmdinfo_t extsize_cmd;
+static cmdinfo_t inode_cmd;
 static prid_t prid;
 static long extsize;
 
@@ -750,6 +752,136 @@ statfs_f(
 	return 0;
 }
 
+static void
+inode_help(void)
+{
+	printf(_(
+"\n"
+"Query physical information about the inode"
+"\n"
+" Default:	-- Return true(1) or false(0) if any inode greater than\n"
+"		   32bits has been found in the filesystem\n"
+" -v		-- verbose mode\n"
+"		   Display the number and the physical size (in bits)\n"
+"		   of the largest inode in the filesystem\n"
+"[num]		-- Return true(1) or false(0) if the inode [num] is in use\n"
+" -n [num]	-- Return the next valid inode after [num]\n"
+"\n"));
+}
+
+static int
+inode_f(
+	  int			argc,
+	  char			**argv)
+{
+	__s32			count = 0;
+	__s32			lastgrp = 0;
+	__u64			last = 0;
+	__u64			lastino = 0;
+	__u64			userino = 0;
+	char			*p;
+	int			c;
+	int			verbose = 0;
+	int			ret_next = 0;
+	int			cmd = 0;
+	struct xfs_inogrp	igroup[1024];
+	struct xfs_fsop_bulkreq	bulkreq;
+	struct xfs_bstat	bstat;
+
+	while ((c = getopt(argc, argv, "nv")) != EOF) {
+		switch (c) {
+		case 'v':
+			verbose = 1;
+			break;
+		case 'n':
+			ret_next = 1;
+			break;
+		default:
+			return command_usage(&inode_cmd);
+		}
+	}
+
+	if (ret_next && verbose)
+		return command_usage(&inode_cmd);
+
+	if (optind < argc) {
+		if (verbose)
+			return command_usage(&inode_cmd);
+
+		if (ret_next) {
+			cmd = XFS_IOC_FSBULKSTAT;
+		} else {
+			if (argc > 2)
+				return command_usage(&inode_cmd);
+			else
+				cmd = XFS_IOC_FSBULKSTAT_SINGLE;
+		}
+
+		userino = strtoull(argv[optind], &p, 10);
+		if ((*p != '\0')) {
+			printf(_("[num] must be a numeric value\n"));
+			exitcode = 1;
+			return 0;
+		}
+
+		bulkreq.lastip = &userino;
+		bulkreq.icount = 1;
+		bulkreq.ubuffer = &bstat;
+		bulkreq.ocount = &count;
+
+		if (xfsctl(file->name, file->fd, cmd, &bulkreq)) {
+			if (errno == EINVAL) {
+				if (!ret_next)
+					printf("0\n");
+			} else {
+				perror("xfsctl");
+			}
+			exitcode = 1;
+			return 0;
+		}
+
+		if (ret_next) {
+			printf("%llu\n", bstat.bs_ino);
+			return 0;
+		} else {
+			/* Inode number used*/
+			printf("1\n");
+			return 0;
+		}
+	}
+
+	bulkreq.lastip = &last;
+	bulkreq.icount = 1024; /* User-defined maybe!? */
+	bulkreq.ubuffer = &igroup;
+	bulkreq.ocount = &count;
+
+	for (;;) {
+		if (xfsctl(file->name, file->fd, XFS_IOC_FSINUMBERS,
+				&bulkreq)) {
+			perror("XFS_IOC_FSINUMBERS");
+			exitcode = 1;
+			return 0;
+		}
+
+		if (count == 0)
+			break;
+
+		lastgrp = count;
+	}
+
+	lastgrp--;
+	lastino = igroup[lastgrp].xi_startino +
+		  xfs_highbit64(igroup[lastgrp].xi_allocmask);
+
+	if (verbose)
+		printf("%llu:%d\n", lastino,
+			lastino > XFS_MAXINUMBER_32 ? 64 : 32);
+	else
+		printf("%d\n", lastino > XFS_MAXINUMBER_32 ? 1 : 0);
+
+	return 0;
+}
+
 void
 open_init(void)
 {
@@ -815,6 +947,16 @@ open_init(void)
 		_("get/set preferred extent size (in bytes) for the open file");
 	extsize_cmd.help = extsize_help;
 
+	inode_cmd.name = "inode";
+	inode_cmd.cfunc = inode_f;
+	inode_cmd.args = _("[-n | -v] [num]");
+	inode_cmd.argmin = 0;
+	inode_cmd.argmax = 2;
+	inode_cmd.flags = CMD_NOMAP_OK;
+	inode_cmd.oneline =
+		_("Query inode number usage in the filesystem");
+	inode_cmd.help = inode_help;
+
 	add_command(&open_cmd);
 	add_command(&stat_cmd);
 	add_command(&close_cmd);
@@ -822,4 +964,5 @@ open_init(void)
 	add_command(&chproj_cmd);
 	add_command(&lsproj_cmd);
 	add_command(&extsize_cmd);
+	add_command(&inode_cmd);
 }
-- 
2.4.3