fat/msdos timestamps are stored on-disk with several different granularities, some of them lower resolution than timespec64_trunc() can provide. In addition, they are only truncated as they are written to disk, so the timestamps in-memory for new or modified files/directories may be different from the same timestamps after a remount, as the now-truncated times are re-read from the on-disk format. These patches allow finer granularity for the timestamps where possible and add fat-specific ->update_time inode operation and fat_truncate_time functions to truncate each timestamp correctly, giving consistent times across remounts. V4 changes corrected to use fat_truncate_time() and keep mark_inode_dirty() set s_time_gran to 1ns unconditionally add i_version support to update_time() fix atime bug with localtime Frank Sorenson (4): fat: create a function to calculate the timezone offest fat: add functions to update and truncate timestamps appropriately fat: change timestamp updates to use fat_truncate_time fat: truncate inode timestamp updates in setattr fs/fat/dir.c | 2 +- fs/fat/fat.h | 2 ++ fs/fat/file.c | 17 ++++++++-- fs/fat/inode.c | 9 ++++-- fs/fat/misc.c | 91 ++++++++++++++++++++++++++++++++++++++++++++++++---- fs/fat/namei_msdos.c | 17 +++++----- fs/fat/namei_vfat.c | 15 +++++---- 7 files changed, 126 insertions(+), 27 deletions(-) -- 2.14.4
