Revise the patch to be available to the latest linux-2.6.git tree. ---------------------------------------------------------------------- Add the ability to 'resize' the loop device on the fly. This may be practically very useful. One practical application is a loop file with XFS filesystem, already mounted: You can easily enlarge the file (append some bytes) and then call ioctl(fd, LOOP_SET_CAPACITY, new); The loop driver will learn about the new size and you can use xfs_growfs later on, which will allow you to use full capacity of the loop file without the need to unmount. Signed-off-by: J. R. Okajima <hooanon05@xxxxxxxxxxx> Signed-off-by: Tomas Matejicek <tomas@xxxxxxxx> --- drivers/block/loop.c | 26 ++++++++++++++++++++++++++ include/linux/loop.h | 1 + 2 files changed, 27 insertions(+), 0 deletions(-) diff --git a/drivers/block/loop.c b/drivers/block/loop.c index 5c4ee70..a034bf9 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -1137,6 +1137,28 @@ loop_get_status64(struct loop_device *lo, struct loop_info64 __user *arg) { return err; } +static int loop_set_capacity(struct loop_device *lo, struct block_device *bdev) +{ + int err; + sector_t sec; + loff_t sz; + + err = -ENXIO; + if (unlikely(lo->lo_state != Lo_bound)) + goto out; + err = figure_loop_size(lo); + if (unlikely(err)) + goto out; + sec = get_capacity(lo->lo_disk); + sz = sec << 9; + mutex_lock(&bdev->bd_mutex); + bd_set_size(bdev, sz); + mutex_unlock(&bdev->bd_mutex); + + out: + return err; +} + static int lo_ioctl(struct block_device *bdev, fmode_t mode, unsigned int cmd, unsigned long arg) { @@ -1166,6 +1188,9 @@ static int lo_ioctl(struct block_device *bdev, fmode_t mode, case LOOP_GET_STATUS64: err = loop_get_status64(lo, (struct loop_info64 __user *) arg); break; + case LOOP_SET_CAPACITY: + err = loop_set_capacity(lo, bdev); + break; default: err = lo->ioctl ? lo->ioctl(lo, cmd, arg) : -EINVAL; } @@ -1311,6 +1336,7 @@ static int lo_compat_ioctl(struct block_device *bdev, fmode_t mode, lo, (struct compat_loop_info __user *) arg); mutex_unlock(&lo->lo_ctl_mutex); break; + case LOOP_SET_CAPACITY: case LOOP_CLR_FD: case LOOP_GET_STATUS64: case LOOP_SET_STATUS64: diff --git a/include/linux/loop.h b/include/linux/loop.h index 46169a7..e9e002a 100644 --- a/include/linux/loop.h +++ b/include/linux/loop.h @@ -160,5 +160,6 @@ int loop_unregister_transfer(int number); #define LOOP_SET_STATUS64 0x4C04 #define LOOP_GET_STATUS64 0x4C05 #define LOOP_CHANGE_FD 0x4C06 +#define LOOP_SET_CAPACITY 0x4C07 #endif -- -- To unsubscribe from this list: send the line "unsubscribe util-linux-ng" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html