Add the lseek SEEK_DATA/SEEK_HOLE support into xfs_io.
The result from the lseek() call will be printed to the output.
For example:
xfs_io> lseek -h 609k
Type Offset
hole 630784
Signed-off-by: Mark Tinguely <tinguely@xxxxxxx>
---
v1 -> v2 Add "-a" and "-r" options.
Simplify the output.
v2 -> v3 Refactor for configure.in -> configure.ac change.
SEEK_DATA with -1 offset behaves badly on older Linux.
Display error message as "ERR <errno>".
v3 -> v4 Change command name to "seek"
Modified detection of first data/hole.
Separate output routine.
Single loop to handle each data/hole item.
configure.ac | 1
include/builddefs.in | 1
io/Makefile | 5 +
io/init.c | 1
io/io.h | 6 +
io/seek.c | 164 ++++++++++++++++++++++++++++++++++++++++++++++++++
m4/package_libcdev.m4 | 15 ++++
man/man8/xfs_io.8 | 35 ++++++++++
8 files changed, 228 insertions(+)
Index: seek_xfsprogs/configure.ac
===================================================================
--- seek_xfsprogs.orig/configure.ac
+++ seek_xfsprogs/configure.ac
@@ -110,6 +110,7 @@ AC_HAVE_GETMNTINFO
AC_HAVE_FALLOCATE
AC_HAVE_FIEMAP
AC_HAVE_PREADV
+AC_HAVE_SEEK_DATA
AC_HAVE_SYNC_FILE_RANGE
AC_HAVE_BLKID_TOPO($enable_blkid)
Index: seek_xfsprogs/include/builddefs.in
===================================================================
--- seek_xfsprogs.orig/include/builddefs.in
+++ seek_xfsprogs/include/builddefs.in
@@ -102,6 +102,7 @@ HAVE_GETMNTINFO = @have_getmntinfo@
HAVE_FALLOCATE = @have_fallocate@
HAVE_FIEMAP = @have_fiemap@
HAVE_PREADV = @have_preadv@
+HAVE_SEEK_DATA = @have_seek_data@
HAVE_SYNC_FILE_RANGE = @have_sync_file_range@
GCCFLAGS = -funsigned-char -fno-strict-aliasing -Wall
Index: seek_xfsprogs/io/Makefile
===================================================================
--- seek_xfsprogs.orig/io/Makefile
+++ seek_xfsprogs/io/Makefile
@@ -80,6 +80,11 @@ ifeq ($(HAVE_PREADV),yes)
LCFLAGS += -DHAVE_PREADV -DHAVE_PWRITEV
endif
+ifeq ($(HAVE_SEEK_DATA),yes)
+LCFLAGS += -DHAVE_SEEK_DATA
+CFILES += seek.c
+endif
+
default: depend $(LTCOMMAND)
include $(BUILDRULES)
Index: seek_xfsprogs/io/init.c
===================================================================
--- seek_xfsprogs.orig/io/init.c
+++ seek_xfsprogs/io/init.c
@@ -64,6 +64,7 @@ init_commands(void)
help_init();
imap_init();
inject_init();
+ seek_init();
madvise_init();
mincore_init();
mmap_init();
Index: seek_xfsprogs/io/io.h
===================================================================
--- seek_xfsprogs.orig/io/io.h
+++ seek_xfsprogs/io/io.h
@@ -108,6 +108,12 @@ extern void quit_init(void);
extern void shutdown_init(void);
extern void truncate_init(void);
+#ifdef HAVE_SEEK_DATA
+extern void seek_init(void);
+#else
+#define seek_init() do { } while (0)
+#endif
+
#ifdef HAVE_FADVISE
extern void fadvise_init(void);
#else
Index: seek_xfsprogs/io/seek.c
===================================================================
--- /dev/null
+++ seek_xfsprogs/io/seek.c
@@ -0,0 +1,174 @@
+/*
+ * Copyright (c) 2012 SGI
+ * All Rights Reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it would be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <libxfs.h>
+#include <linux/fs.h>
+
+#include <sys/uio.h>
+#include <xfs/xfs.h>
+#include <xfs/command.h>
+#include <xfs/input.h>
+#include <ctype.h>
+#include "init.h"
+#include "io.h"
+
+static cmdinfo_t seek_cmd;
+
+static void
+seek_help(void)
+{
+ printf(_(
+"\n"
+" returns the next hole and/or data offset at or after the specified offset\n"
+"\n"
+" Example:\n"
+" 'seek -d 512' - offset of data at or following offset 512\n"
+" 'seek -a -r 0' - offsets of all data and hole in entire file\n"
+"\n"
+" Returns the offset of the next data and/or hole. There is an implied hole\n"
+" at the end of file. If the specified offset is past end of file, or there\n"
+" is no data past the specied offset, EOF is returned.\n"
+" -a -- return the next data and hole starting at the specified offset.\n"
+" -d -- return the next data starting at the specified offset.\n"
+" -h -- return the next hole starting at the specified offset.\n"
+" -r -- return all remaining type(s) starting at the specified offset.\n"
+"\n"));
+}
+
+#define SEEK_DFLAG (1 << 0)
+#define SEEK_HFLAG (1 << 1)
+#define SEEK_RFLAG (1 << 2)
+#define DATA 0
+#define HOLE 1
+
+struct seekinfo {
+ char *name;
+ int seektype;
+ int mask;
+} seekinfo[] = {
+ {"DATA", SEEK_DATA, SEEK_DFLAG},
+ {"HOLE", SEEK_HOLE, SEEK_HFLAG}
+};
+
+void
+seek_output(
+ char *name,
+ off64_t offset)
+{
+ if (offset == -1) {
+ if (errno == ENXIO)
+ printf("%s EOF\n", name);
+ else
+ printf("%s ERR %d\n", name, errno);
+ } else
+ printf("%s %ld\n", name, offset);
+}
+
+static int
+seek_f(
+ int argc,
+ char **argv)
+{
+ off64_t offset, result;
+ size_t fsblocksize, fssectsize;
+ int flag;
+ int type; /* specify data or hole */
+ int c;
+
+ flag = 0;
+ init_cvtnum(&fsblocksize, &fssectsize);
+
+ while ((c = getopt(argc, argv, "adhr")) != EOF) {
+ switch (c) {
+ case 'a':
+ flag |= (SEEK_HFLAG | SEEK_DFLAG);
+ break;
+ case 'd':
+ flag |= SEEK_DFLAG;
+ break;
+ case 'h':
+ flag |= SEEK_HFLAG;
+ break;
+ case 'r':
+ flag |= SEEK_RFLAG;
+ break;
+ default:
+ return command_usage(&seek_cmd);
+ }
+ }
+ /* must have hole or data specified and an offset */
+ if (!(flag & (SEEK_DFLAG | SEEK_HFLAG)) ||
+ optind != argc - 1)
+ return command_usage(&seek_cmd);
+
+ offset = cvtnum(fsblocksize, fssectsize, argv[optind]);
+
+ if (flag & SEEK_HFLAG) {
+ result = lseek64(file->fd, offset, SEEK_HOLE);
+ if ((result == offset) ||
+ !(flag & SEEK_DFLAG)) {
+ offset = result; /* in case it was EOF */
+ type = HOLE;
+ goto found_hole;
+ }
+ }
+
+ /* found data or both hole and data results in a -1 */
+ type = DATA;
+ offset = lseek64(file->fd, offset, SEEK_DATA);
+
+found_hole:
+ printf("Type offset\n");
+
+ /* loop to handle the data / hole entries in assending order. */
+ while (flag) {
+ if (flag & seekinfo[type].mask)
+ seek_output(seekinfo[type].name, offset);
+
+ /* stop on error or when the EOF has been detected */
+ if (offset == -1)
+ break;
+
+ /* For the case of display only a single data and/or hole
+ * item, mask off the item just displayed. The loop will
+ * end when all the requested items have been displayed.
+ */
+ if (!(flag & SEEK_RFLAG))
+ flag ^= seekinfo[type].mask;
+
+ type ^= 1; /* alternate between data and hole */
+ offset = lseek64(file->fd, offset, seekinfo[type].seektype);
+ }
+ return 0;
+}
+
+void
+seek_init(void)
+{
+ seek_cmd.name = "seek";
+ seek_cmd.altname = "seek";
+ seek_cmd.cfunc = seek_f;
+ seek_cmd.argmin = 2;
+ seek_cmd.argmax = 5;
+ seek_cmd.flags = CMD_NOMAP_OK | CMD_FOREIGN_OK;
+ seek_cmd.args = _("-a | -d | -h [-r] off");
+ seek_cmd.oneline = _("locate the next data and/or hole");
+ seek_cmd.help = seek_help;
+
+ add_command(&seek_cmd);
+}
Index: seek_xfsprogs/m4/package_libcdev.m4
===================================================================
--- seek_xfsprogs.orig/m4/package_libcdev.m4
+++ seek_xfsprogs/m4/package_libcdev.m4
@@ -153,6 +153,21 @@ AC_DEFUN([AC_HAVE_PREADV],
AC_SUBST(have_preadv)
])
+#
+# Check if we have a working fadvise system call
+#
+AC_DEFUN([AC_HAVE_SEEK_DATA],
+ [ AC_MSG_CHECKING([for lseek SEEK_DATA])
+ AC_TRY_COMPILE([
+#include <linux/fs.h>
+ ], [
+ lseek(0, 0, SEEK_DATA);
+ ], have_seek_data=yes
+ AC_MSG_RESULT(yes),
+ AC_MSG_RESULT(no))
+ AC_SUBST(have_seek_data)
+ ])
+
#
# Check if we have a sync_file_range libc call (Linux)
#
Index: seek_xfsprogs/man/man8/xfs_io.8
===================================================================
--- seek_xfsprogs.orig/man/man8/xfs_io.8
+++ seek_xfsprogs/man/man8/xfs_io.8
@@ -377,6 +377,41 @@ must be specified as another open file
.RB ( \-f )
or by path
.RB ( \-i ).
+.TP
+.BI "seek \-a | \-d | \-h [ \-r ] offset"
+On platforms that support the
+.BR lseek (2)
+.B SEEK_DATA
+and
+.B SEEK_HOLE
+options, display the offsets of the specified segments.
+.RS 1.0i
+.PD 0
+.TP 0.4i
+.B \-a
+Display both
+.B data
+and
+.B hole
+segments starting at the specified
+.B offset.
+.TP
+.B \-d
+Display the
+.B data
+segment starting at the specified
+.B offset.
+.TP
+.B \-h
+Display the
+.B hole
+segment starting at the specified
+.B offset.
+.TP
+.B \-r
+Recursively display all the specified segments starting at the specified
+.B offset.
+.TP
.SH MEMORY MAPPED I/O COMMANDS
.TP
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