From: Arnd Bergmann <arnd@xxxxxxxx> Subject: shmem: use monotonic time for i_generation get_seconds() is deprecated because it will lead to a 32-bit overflow in 2038 or 2106. We don't need the i_generation to be strictly monotonic anyway, and other file systems like ext4 and xfs just use prandom_u32(), so let's use the same one here. If this is considered too slow, we could also use ktime_get_seconds() or ktime_get_real_seconds() to keep the previous behavior. Both of these return a time64_t and are not deprecated, but only return a unique value once per second, and are predictable. Link: http://lkml.kernel.org/r/20180620082556.581543-1-arnd@xxxxxxxx Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx> Reviewed-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Cc: Hugh Dickins <hughd@xxxxxxxxxx> Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx> Cc: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/shmem.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/mm/shmem.c~shmem-use-monotonic-time-for-i_generation +++ a/mm/shmem.c @@ -29,6 +29,7 @@ #include <linux/pagemap.h> #include <linux/file.h> #include <linux/mm.h> +#include <linux/random.h> #include <linux/sched/signal.h> #include <linux/export.h> #include <linux/swap.h> @@ -2188,7 +2189,7 @@ static struct inode *shmem_get_inode(str inode_init_owner(inode, dir, mode); inode->i_blocks = 0; inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode); - inode->i_generation = get_seconds(); + inode->i_generation = prandom_u32(); info = SHMEM_I(inode); memset(info, 0, (char *)inode - (char *)info); spin_lock_init(&info->lock); _
