Messages in this thread Patch in this message | | | Date | Tue, 23 May 2006 15:31:29 +0800 | From | Akinobu Mita <> | Subject | [PATCH] loop: online resize support |
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This patch introduces new ioctl command LOOP_UPDATE_SIZE which enables to resize online mounted loop device.
EXAMPLE ======= # Make 10MB disk image # dd if=/dev/zero of=image bs=1k count=10k # mkfs.ext3 -j -F image
# Mount # mkdir loop # mount -o loop=/dev/loop/0,debug -t ext3 image loop
# Check disk size # df -h loop Filesystem Size Used Avail Use% Mounted on /home/mita/looback-test/image 9.7M 1.1M 8.2M 12% /home/mita/looback-test/loop
# Extend disk image to 20MB # dd if=/dev/zero of=appendix bs=1k count=10k # cat appendix >> image
# Resize # gcc -o loop-update loop-update.c # ./loop-update /dev/loop/0 # ext2online -d -v image
# Check disk size again # df -h loop Filesystem Size Used Avail Use% Mounted on /home/mita/looback-test/image 20M 1.1M 18M 6% /home/mita/looback-test/loop
loop-update.c ============= #include <stdlib.h> #include <stdio.h> #include <unistd.h> #include <sys/ioctl.h> #include <sys/types.h> #include <sys/stat.h> #include <fcntl.h>
#define LOOP_UPDATE_SIZE 0x4C07
int main(int argc, char **argv) { int fd; int err;
if (argc < 2) { fprintf(stderr, "usage: loop-update loop_device\n"); exit(1); }
fd = open(argv[1], O_RDWR); if (fd < 0) { perror(argv[1]); exit(1); }
err = ioctl(fd, LOOP_UPDATE_SIZE, NULL); if (err) { perror(argv[1]); exit(1); } }
CC: Jens Axboe <axboe@suse.de> CC: "Theodore Ts'o" <tytso@mit.edu> Signed-off-by: Akinobu Mita <mita@miraclelinux.com>
--- 2.6-mm/include/linux/loop.h.orig 2006-05-23 12:52:54.000000000 +0800 +++ 2.6-mm/include/linux/loop.h 2006-05-23 12:59:14.000000000 +0800 @@ -158,5 +158,6 @@ int loop_unregister_transfer(int number) #define LOOP_SET_STATUS64 0x4C04 #define LOOP_GET_STATUS64 0x4C05 #define LOOP_CHANGE_FD 0x4C06 +#define LOOP_UPDATE_SIZE 0x4C07 #endif --- 2.6-mm/drivers/block/loop.c.orig 2006-05-23 12:51:11.000000000 +0800 +++ 2.6-mm/drivers/block/loop.c 2006-05-23 13:50:58.000000000 +0800 @@ -1108,7 +1108,8 @@ loop_set_status64(struct loop_device *lo } static int -loop_get_status_old(struct loop_device *lo, struct loop_info __user *arg) { +loop_get_status_old(struct loop_device *lo, struct loop_info __user *arg) +{ struct loop_info info; struct loop_info64 info64; int err = 0; @@ -1126,7 +1127,8 @@ loop_get_status_old(struct loop_device * } static int -loop_get_status64(struct loop_device *lo, struct loop_info64 __user *arg) { +loop_get_status64(struct loop_device *lo, struct loop_info64 __user *arg) +{ struct loop_info64 info64; int err = 0; @@ -1140,6 +1142,17 @@ loop_get_status64(struct loop_device *lo return err; } +static int loop_update_size(struct loop_device *lo) +{ + int err = figure_loop_size(lo); + + if (!err) + i_size_write(lo->lo_device->bd_inode, + (loff_t) get_capacity(disks[lo->lo_number]) << 9); + + return err; +} + static int lo_ioctl(struct inode * inode, struct file * file, unsigned int cmd, unsigned long arg) { @@ -1169,6 +1182,9 @@ static int lo_ioctl(struct inode * inode case LOOP_GET_STATUS64: err = loop_get_status64(lo, (struct loop_info64 __user *) arg); break; + case LOOP_UPDATE_SIZE: + err = loop_update_size(lo); + break; default: err = lo->ioctl ? lo->ioctl(lo, cmd, arg) : -EINVAL; } - 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/
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