[PATCH] xfs_io: implement 'inode' command V6

[Carlos Maiolino <cmaiolino@redhat.com>]

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
[num]        -- Return inode number or 0 if the inode [num] is in use
-n [num]     -- Return the next valid inode after [num]
-v           -- verbose mode
                Display the inode number and its physical size according to the
		argument used

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

V6:
	- Re-use userino variable to reduce code duplication for command output
	- Use verbose option as an extension to another commands
	- report usage message when -n option is passed stand-alone
	- Refactor command outputs
	- Add a few comments to the code

Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com>
---
 io/open.c | 150 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 150 insertions(+)

diff --git a/io/open.c b/io/open.c
index 037843d..5e607f1 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 +752,143 @@ 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"
+"[num]		-- Return inode number [num] or 0 if the inode [num] is in use\n"
+"		   or not\n"
+" -n [num]	-- Return the next valid inode after [num]\n"
+" -v		-- verbose mode\n"
+"		   Display the inode number and its physical size (in bits)\n"
+"		   according to the argument used\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);
+		}
+	}
+
+	/*
+	 * Inode number can be passed with or without extra arguments, so we
+	 * should handle inode numbers passed by user out of getopt()
+	 */
+	if (optind < argc) {
+
+		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)
+			userino = bstat.bs_ino;
+
+		if (verbose)
+			printf("%llu:%d\n",
+			       userino,
+			       userino > XFS_MAXINUMBER_32 ? 64 : 32);
+		else
+			/* Inode in use */
+			printf("%llu\n", userino);
+		return 0;
+
+	/* -n option must not be used stand alone */
+	} else if (ret_next) {
+		return command_usage(&inode_cmd);
+	}
+
+	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 +954,16 @@ 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 +971,5 @@ open_init(void)
 	add_command(&chproj_cmd);
 	add_command(&lsproj_cmd);
 	add_command(&extsize_cmd);
+	add_command(&inode_cmd);
 }
-- 
2.4.3

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