On Mon, 2024-07-08 at 11:47 -0700, Darrick J. Wong wrote: > On Mon, Jul 08, 2024 at 11:53:39AM -0400, Jeff Layton wrote: > > Enable multigrain timestamps, which should ensure that there is an > > apparent change to the timestamp whenever it has been written after > > being actively observed via getattr. > > > > Also, anytime the mtime changes, the ctime must also change, and those > > are now the only two options for xfs_trans_ichgtime. Have that function > > unconditionally bump the ctime, and ASSERT that XFS_ICHGTIME_CHG is > > always set. > > > > Finally, stop setting STATX_CHANGE_COOKIE in getattr, since the ctime > > should give us better semantics now. > > > > Signed-off-by: Jeff Layton <jlay...@kernel.org> > > --- > > fs/xfs/libxfs/xfs_trans_inode.c | 6 +++--- > > fs/xfs/xfs_iops.c | 10 +++------- > > fs/xfs/xfs_super.c | 2 +- > > 3 files changed, 7 insertions(+), 11 deletions(-) > > > > diff --git a/fs/xfs/libxfs/xfs_trans_inode.c > > b/fs/xfs/libxfs/xfs_trans_inode.c > > index 69fc5b981352..1f3639bbf5f0 100644 > > --- a/fs/xfs/libxfs/xfs_trans_inode.c > > +++ b/fs/xfs/libxfs/xfs_trans_inode.c > > @@ -62,12 +62,12 @@ xfs_trans_ichgtime( > > ASSERT(tp); > > xfs_assert_ilocked(ip, XFS_ILOCK_EXCL); > > > > - tv = current_time(inode); > > + /* If the mtime changes, then ctime must also change */ > > + ASSERT(flags & XFS_ICHGTIME_CHG); > > > > + tv = inode_set_ctime_current(inode); > > if (flags & XFS_ICHGTIME_MOD) > > inode_set_mtime_to_ts(inode, tv); > > - if (flags & XFS_ICHGTIME_CHG) > > - inode_set_ctime_to_ts(inode, tv); > > if (flags & XFS_ICHGTIME_CREATE) > > ip->i_crtime = tv; > > } > > diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c > > index a00dcbc77e12..d25872f818fa 100644 > > --- a/fs/xfs/xfs_iops.c > > +++ b/fs/xfs/xfs_iops.c > > @@ -592,8 +592,9 @@ xfs_vn_getattr( > > stat->gid = vfsgid_into_kgid(vfsgid); > > stat->ino = ip->i_ino; > > stat->atime = inode_get_atime(inode); > > - stat->mtime = inode_get_mtime(inode); > > - stat->ctime = inode_get_ctime(inode); > > + > > + fill_mg_cmtime(stat, request_mask, inode); > > Sooo... for setting up a commit-range operation[1], XFS_IOC_START_COMMIT > could populate its freshness data by calling: > > struct kstat dummy; > > fill_mg_ctime(&dummy, STATX_CTIME | STATX_MTIME, inode); > > and then using dummy.[cm]time to populate the freshness data that it > gives to userspace, right? Having set QUERIED, a write to the file > immediately afterwards will cause a (tiny) increase in ctime_nsec which > will cause the XFS_IOC_COMMIT_RANGE to reject the commit[2]. Right? >
Yes. Once you call fill_mg_ctime, the first write after that point should cause the kernel to ensure that there is a distinct change in the ctime. IOW, I think this should alleviate the concerns I had before with using timestamps with the XFS_IOC_COMMIT_RANGE interface. > --D > > [1] https://lore.kernel.org/linux-xfs/20240227174649.GL6184@frogsfrogsfrogs/ > [2] > https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux.git/commit/?h=atomic-file-commits&id=0520d89c2698874c1f56ddf52ec4b8a3595baa14 > > > + > > stat->blocks = XFS_FSB_TO_BB(mp, ip->i_nblocks + ip->i_delayed_blks); > > > > if (xfs_has_v3inodes(mp)) { > > @@ -603,11 +604,6 @@ xfs_vn_getattr( > > } > > } > > > > - if ((request_mask & STATX_CHANGE_COOKIE) && IS_I_VERSION(inode)) { > > - stat->change_cookie = inode_query_iversion(inode); > > - stat->result_mask |= STATX_CHANGE_COOKIE; > > - } > > - > > /* > > * Note: If you add another clause to set an attribute flag, please > > * update attributes_mask below. > > diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c > > index 27e9f749c4c7..210481b03fdb 100644 > > --- a/fs/xfs/xfs_super.c > > +++ b/fs/xfs/xfs_super.c > > @@ -2052,7 +2052,7 @@ static struct file_system_type xfs_fs_type = { > > .init_fs_context = xfs_init_fs_context, > > .parameters = xfs_fs_parameters, > > .kill_sb = xfs_kill_sb, > > - .fs_flags = FS_REQUIRES_DEV | FS_ALLOW_IDMAP, > > + .fs_flags = FS_REQUIRES_DEV | FS_ALLOW_IDMAP | FS_MGTIME, > > }; > > MODULE_ALIAS_FS("xfs"); > > > > > > -- > > 2.45.2 > > > > -- Jeff Layton <jlay...@kernel.org>
