= Problem = = Plan = === 1.Plan for VFS === || Milestone || # of patches || Status || Targeted Kernel release || || Infrastructure patches for vfs_time and granularity fields 1.4.1 and 1.4.2 || 2 || Done || 4.7- rc1 || || Test time ranges beyond y2038 support, in memory timestamps match with on disk -1.3.1 and 1.3.2 || Xfs tests || In progress || 5/28/16 || || Replace CURRENT_TIME and CURRENT_TIME_SEC – 1.2.1 || ~60 || In Progress, waiting for 4.7 rc1 and repost previous. || 4.8 || || Vfs_time patches – 1.4.3 || ~40 || In Progress, waiting for 4.7-rc1 || 4.8 || || Fill in right granularities and ranges for FS – 1.2.2 and 1.2.3 || ~40 || Yet to start || 4.8 || || Expose FS granularities and ranges – 1.4.5 and 1.4.6 || ~5 || Yet to start || 4.8 || || Tests to check the granularities and ranges – 1.3.3 and 1.3.4 || Xfs tests || Yet to start || 6/10/16 || || Add policy for wrong granularities - 1.4.7 || RFC for 4.9 || Yet to start || || || Stat and utime changes – 1.4.8 || RFC for 4.9 || Yet to start || || || Tests for I_DIRTY_* flags and mount options -1.3.5 and 1.3.6 || Xfs tests || Yet to start || 6/30/16 || || Transition vfs to 64 bit – 1.4.4 || 2 || Ready, wait for other patches to merge || 4.10 || === 1.2 Cleanup === There are many clean up tasks that must precede the transitioning of VFS to use 64 bit timestamps. These help streamline the main series. '''1.2.1 Replace current_time and current_time_sec''' This patch series is aimed at getting rid of CURRENT_TIME and CURRENT_TIME_SEC macros. The macros: CURRENT_TIME and CURRENT_TIME_SEC are primarily used for filesystem timestamps. to the granularity as required by the filesystem. There will also be another series to add range checks and clamping to filesystem time functions that are meant to substitute the above macros: {{{ struct timespec current_fs_time(struct super_block *sb)}}} {{{ struct timespec current_fs_time_sec(struct super_block *sb)}}} These time functions will also be transitioned along with VFS to use struct timespec64 instead of struct timespec. Any use of these macros outside of filesystem timestamps will be replaced by ktime_get*/ get_seconds functions. Links to posted patches: 1. http://thread.gmane.org/gmane.linux.file-systems/106912 (Infrastructure patch) 1. https://lkml.org/lkml/2016/2/3/34 1. https://lkml.org/lkml/2016/2/22/506 '''1.2.2 Fill in right granularities ''' The series is aimed at filling in right granularities in the s_time_gran field of struct super_block. The filed is used to determine the right granularity for nanosecond portion of inode timestamps. Some filesystems, for instance FAT do not initialize granularity fields since they only care about the seconds portion of the timestamps. This will lead to inconsistencies in the in memory timestamps compared to on disk ones as the filesystem uses VFS generic_update_time() which does not clear nanosecond field before updating the inode timestamps. Similar patches need to be submitted for other filesystems with similar issues. '''1.2.3 Fill in right ranges''' The time ranges supported by filesystems vary according to their on disk formats. The in memory version of the inode timestamps need to match the on disk version. The plan is for VFS to truncate filesystem timestamps according to their limits. Links posted: 1. http://www.spinics.net/lists/linux-fsdevel/msg96564.html (Infrastructure patch)[http://www.spinics.net/lists/linux-fsdevel/msg96564.html ] === 1.3 Test === '''1.3.1 Test time written on disk and in memory are same''' '''1.3.2 Test time ranges beyond y2038''' '''1.3.3''' T'''est time granularities are what the fs needs''' '''''' '''1.3.4''' '''Test time ranges supported are same as what fs reports''' '''1.3.5''' '''Perf tests''' '''1.3.6''' '''Test to check i_dirty_* flags are updating correctly''' '''1.3.7''' '''Test to check with different mount options like lazy atime etc.''' === 1.4 Kernel tasks to transition vfs to use 64 bit times === '''1.4.1''' '''Infrastructure patches for vfs_time approach''' '''1.4.3''' '''Change each fs to use vfs time patches ''' '''1.4.4''' '''Change vfs to use timespec64''' '''1.4.5''' '''Expose fs granularities''' '''1.4.6''' '''Expose fs ranges''' '''1.4.7''' '''Add vfs policy for handling wrong ranges and granularity''' '''1.4.8''' '''Stat and utime api changes''' === 1.5 Runtime library === '''1.5.1''' '''Make changes in one library''' '''1.5.2''' '''Make it part of some userspace and run it ''' == Overview of file systems == Each file system stores its file modification times in its own format on disk, and a lot of them have the same problem. || file system || time type || expiration year || || 9p (9P2000) || unsigned 32-bit seconds || 2106 || || file system || time type || expiration year || || 9p (9P2000) || unsigned 32-bit seconds || 2106 || || 9p (9P2000.L) || signed 64-bit seconds, ns || never || || adfs || 40-bit cs since 1900 || 2248 || || affs || u32 days/mins/(secs/50) || 11760870 || || afs || unsigned 32-bit seconds || 2106 || || befs || unsigned 48-bit seconds || never || || bfs || unsigned 32-bit seconds || 2106 || || btrfs || signed 64-bit seconds, 32-bit ns || never || || ceph || unsigned 32-bit second/ns || 2106 || || cifs (smb) || 7-bit years since 1980 || 2107 || || cifs (modern) || 64-bit 100ns since 1601 || 30328 || || coda || timespec ioctl || 2038 || || cramfs || fixed || 1970 || || efs || unsigned 32-bit seconds || 2106 || || exofs || signed 32-bit seconds || 2038 || || ext2 || signed 32-bit seconds || 2038 || || ext3 || signed 32-bit seconds || 2038 || || ext4 (good old inodes) || signed 32-bit seconds || 2038 || || ext4 (new inodes || 34 bit seconds / 30-bit ns || 2582 || || f2fs || 64-bit seconds / 32-bit ns || never || || fat || 7-bit years since 1980, 2s resolution || 2107 || || freevxfs || unsigned 32-bit seconds/u32 microseconds || 2106 || || fuse || 64-bit second/32-bit ns || never || || gfs2 || u64 seconds/u32 ns || never || || hfs || u32 seconds since 1904 || 2040 || || hfsplus || u32 seconds since 1904 || 2040 || || hostfs || timespec || 2038 || || hpfs || unsigned 32-bit seconds || 2106 || || isofs || 'char' year since 1900 (fixable) || 2028 || || jffs2 || unsigned 32-bit seconds || 2106 || || jfs || unsigned 32-bit seconds/ns || 2106 || || logfs || signed 64-bit ns || 2262 || || minix || unsigned 32-bit seconds || 2106 || || ncpfs || 7-bit year since 1980 || 2107 || || nfsv2,v3 || unsigned 32-bit seconds/ns || 2106 || || nfsv4 || u64 seconds/u32 ns || never || || nfsd || unsigned 32-bit seconds/ns || 2106 || || nilfs2 || u64 seconds/u32 ns || never || || ntfs || 64-bit 100ns since 1601 || 30828 || || ocfs2 || 34-bit seconds/30-bit ns || 2514 || || omfs || 64-bit milliseconds || never || || pstore || ascii seconds || 2106 || || qnx4 || unsigned 32-bit seconds || 2106 || || qnx6 || unsigned 32-bit seconds || 2106 || || reiserfs || unsigned 32-bit seconds || 2106 || || romfs || fixed || 1970 || || squashfs || unsigned 32-bit seconds || 2106 || || sysv || unsigned 32-bit seconds || 2106 || || ubifs || u64 second/u32 ns || never || || udf || u16 year || 2038 || || ufs1 || signed 32-bit seconds || 2038 || || ufs2 || signed 64-bit seconds/u32 ns || never || || xfs || signed 32-bit seconds/ns || 2106 ||