A simple user space utility to resize an existing partition. It tries to read the start of partiton from sysfs. This is a real quick dirty patch I used for my testing. I am sure there are better and faster ways of getting to partition "start" from device and partition number. Signed-off-by: Vivek Goyal --- disk-utils/Makemodule.am | 7 +++- disk-utils/partx.h | 19 +++++++++ disk-utils/resizepart.8 | 38 ++++++++++++++++++ disk-utils/resizepart.c | 98 ++++++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 161 insertions(+), 1 deletions(-) create mode 100644 disk-utils/resizepart.8 create mode 100644 disk-utils/resizepart.c diff --git a/disk-utils/Makemodule.am b/disk-utils/Makemodule.am index 830e8f7..b544e87 100644 --- a/disk-utils/Makemodule.am +++ b/disk-utils/Makemodule.am @@ -113,7 +113,7 @@ endif # LINUX if BUILD_PARTX -usrsbin_exec_PROGRAMS += partx addpart delpart +usrsbin_exec_PROGRAMS += partx addpart delpart resizepart dist_man_MANS += \ disk-utils/addpart.8 \ disk-utils/delpart.8 \ @@ -130,6 +130,11 @@ delpart_SOURCES = \ disk-utils/partx.h delpart_LDADD = $(LDADD) libcommon.la +resizepart_SOURCES = \ + disk-utils/resizepart.c \ + disk-utils/partx.h +resizepart_LDADD = $(LDADD) libcommon.la + partx_SOURCES = \ disk-utils/partx.c \ disk-utils/partx.h diff --git a/disk-utils/partx.h b/disk-utils/partx.h index ed0fd0a..02e273e 100644 --- a/disk-utils/partx.h +++ b/disk-utils/partx.h @@ -41,4 +41,23 @@ static inline int partx_add_partition(int fd, int partno, return ioctl(fd, BLKPG, &a); } +static inline int partx_resize_partition(int fd, int partno, + long long start, long long size) +{ + struct blkpg_ioctl_arg a; + struct blkpg_partition p; + + p.pno = partno; + p.start = start << 9; + p.length = size << 9; + p.devname[0] = 0; + p.volname[0] = 0; + a.op = BLKPG_RESIZE_PARTITION; + a.flags = 0; + a.datalen = sizeof(p); + a.data = &p; + + return ioctl(fd, BLKPG, &a); +} + #endif /* UTIL_LINUX_PARTX_H */ diff --git a/disk-utils/resizepart.8 b/disk-utils/resizepart.8 new file mode 100644 index 0000000..c009cc3 --- /dev/null +++ b/disk-utils/resizepart.8 @@ -0,0 +1,38 @@ +.\" resizepart.8 -- +.\" Copyright 2012 Vivek Goyal +.\" Copyright 2012 Red Hat, Inc. +.\" May be distributed under the GNU General Public License +.TH RESIZEPART 8 "February 2012" "util-linux" "System Administration" +.SH NAME +resizepart \- +simple wrapper around the "resize partition" ioctl +.SH SYNOPSIS +.B resizepart +.I device partition length +.SH DESCRIPTION +.B resizepart +is a program that informs the Linux kernel of new partition size. + +This command doesn't manipulate partitions on hard drive. + +.SH PARAMETERS +.TP +.I device +Specify the disk device. +.TP +.I partition +Specify the partition number. +.TP +.I length +Specify the length of the partition (in 512-byte sectors). + +.SH SEE ALSO +.BR addpart (8), +.BR delpart (8), +.BR fdisk (8), +.BR parted (8), +.BR partprobe (8), +.BR partx (8) +.SH AVAILABILITY +The resizepart command is part of the util-linux package and is available from +ftp://ftp.kernel.org/pub/linux/utils/util-linux/. diff --git a/disk-utils/resizepart.c b/disk-utils/resizepart.c new file mode 100644 index 0000000..4f9e9ce --- /dev/null +++ b/disk-utils/resizepart.c @@ -0,0 +1,98 @@ +#include +#include +#include +#include +#include "canonicalize.h" +#include "sysfs.h" +#include "partx.h" + +char * +get_devname_from_canonical_path(char *path) +{ + struct sysfs_cxt cxt; + dev_t devno; + char name[PATH_MAX]; + char *devname; + + devno = sysfs_devname_to_devno(path, NULL); + if (!devno) { + fprintf(stderr, "failed to read devno. \n"); + exit(1); + } + + if (sysfs_init(&cxt, devno, NULL)) { + fprintf(stderr, "failed to initialize sysfs. \n"); + exit(1); + } + devname = sysfs_get_devname(&cxt, name, sizeof(name)); + return strdup(devname); +} + +char * +get_partname_from_devname(char *devname, int partno) +{ + char partname[PATH_MAX]; + + if (isdigit(devname[strlen(devname) - 1])) + snprintf(partname, PATH_MAX, "%sp%d", devname, partno); + else + snprintf(partname, PATH_MAX, "%s%d", devname, partno); + + return strdup(partname); +} + + +int +main(int argc, char **argv) +{ + int fd; + char *real_path, *devname, *partname, *pstart; + char part_sysfs_path[PATH_MAX], part_start[30]; + FILE *fp; + + if (argc != 4) { + fprintf(stderr, + "usage: %s diskdevice partitionnr length\n", + argv[0]); + exit(1); + } + if ((fd = open(argv[1], O_RDONLY)) < 0) { + perror(argv[1]); + exit(1); + } + + real_path = canonicalize_path(argv[1]); + + if (real_path == NULL) { + fprintf(stderr, "canonicalize_path(%s) failed. \n", argv[1]); + exit(1); + } + + devname = get_devname_from_canonical_path(real_path); + partname = get_partname_from_devname(devname, atoi(argv[2])); + + snprintf(part_sysfs_path, PATH_MAX, "/sys/block/%s/%s/start", + devname, partname); + + fp = fopen(part_sysfs_path, "r"); + + if (!fp) { + perror("BLKPG"); + exit(1); + } + + pstart = fgets(part_start, 30, fp); + + if (!pstart) { + perror("BLKPG"); + exit(1); + } + + if (partx_resize_partition(fd, atoi(argv[2]), atoll(pstart), + atoll(argv[3]))) { + perror("BLKPG"); + exit(1); + } + + return 0; +} -- 1.7.7.6 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/