3.15-stable review patch. If anyone has any objections, please let me know.
------------------ From: Minchan Kim <[email protected]> commit 2e32baea46ce542c561a519414c840295b229c8f upstream. Alexander reported mkswap on /dev/zram0 is failed if other process is opening the block device file. Step is as follows, 0. Reset the unused zram device. 1. Use a program that opens /dev/zram0 with O_RDWR and sleeps until killed. 2. While that program sleeps, echo the correct value to /sys/block/zram0/disksize. 3. Verify (e.g. in /proc/partitions) that the disk size is applied correctly. It is. 4. While that program still sleeps, attempt to mkswap /dev/zram0. This fails: mkswap: error: swap area needs to be at least 40 KiB When I investigated, the size get by ioctl(fd, BLKGETSIZE64, xxx) on mkswap to get a size of blockdev was zero although zram0 has right size by 2. The reason is zram didn't revalidate disk after changing capacity so that size of blockdev's inode is not uptodate until all of file is close. This patch should fix the BUG. Signed-off-by: Minchan Kim <[email protected]> Reported-by: Alexander E. Patrakov <[email protected]> Tested-by: Alexander E. Patrakov <[email protected]> Reviewed-by: Sergey Senozhatsky <[email protected]> Cc: Nitin Gupta <[email protected]> Acked-by: Jerome Marchand <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- drivers/block/zram/zram_drv.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) --- a/drivers/block/zram/zram_drv.c +++ b/drivers/block/zram/zram_drv.c @@ -622,8 +622,10 @@ static void zram_reset_device(struct zra memset(&zram->stats, 0, sizeof(zram->stats)); zram->disksize = 0; - if (reset_capacity) + if (reset_capacity) { set_capacity(zram->disk, 0); + revalidate_disk(zram->disk); + } up_write(&zram->init_lock); } @@ -664,6 +666,7 @@ static ssize_t disksize_store(struct dev zram->comp = comp; zram->disksize = disksize; set_capacity(zram->disk, zram->disksize >> SECTOR_SHIFT); + revalidate_disk(zram->disk); up_write(&zram->init_lock); return len; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
