| Message ID | 20240331111744.7224-5-l@damenly.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | ocfs2 bugs fixes exposed by fstests | expand |
On 3/31/24 7:17 PM, Su Yue wrote: > From: Su Yue <glass.su@suse.com> > > The default atime related mount option is '-o realtime' > which means file atime should be updated if atime <= ctime > or atime <= mtime. atime should be updated in the > following scenario, but it is not: > ========================================================== > $ rm /mnt/testfile; > $ echo test > /mnt/testfile > $ stat -c "%X %Y %Z" /mnt/testfile > 1711881646 1711881646 1711881646 > $ sleep 5 > $ cat /mnt/testfile > /dev/null > $ stat -c "%X %Y %Z" /mnt/testfile > 1711881646 1711881646 1711881646 > ========================================================== > > And the reason the atime in the test is not updated is that > ocfs2 calls ktime_get_real_ts64() in __ocfs2_mknod_locked during > file creation. Then inode_set_ctime_current() is called in > inode_set_ctime_current() calls ktime_get_coarse_real_ts64() to > get current time. > ktime_get_real_ts64() is accurater than ktime_get_coarse_real_ts64(). > In my test box, I saw ctime set by ktime_get_coarse_real_ts64() is > less than ktime_get_real_ts64() even ctime is set later. > The ctime of the new inode is smaller than atime. > > The call trace is like: > > ocfs2_create > ocfs2_mknod > __ocfs2_mknod_locked > .... > > ktime_get_real_ts64 <------- set atime,ctime,mtime, more accurate > ocfs2_populate_inode > ... > ocfs2_init_acl > ocfs2_acl_set_mode > inode_set_ctime_current > current_time > ktime_get_coarse_real_ts64 <-------less accurate > > ocfs2_file_read_iter > ocfs2_inode_lock_atime > ocfs2_should_update_atime > atime <= ctime ? <-------- false, ctime < atime due to accuracy > > So here call ktime_get_coarse_real_ts64 to set inode time coarser while > creating new files. It may lower the accuracy of file times. But it's not > a big deal since we already use coarse time in other places like > ocfs2_update_inode_atime and inode_set_ctime_current. > > Signed-off-by: Su Yue <glass.su@suse.com> Looks reasonable. Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com> > --- > fs/ocfs2/namei.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/fs/ocfs2/namei.c b/fs/ocfs2/namei.c > index 55c9d90caaaf..4d1ea8703fcd 100644 > --- a/fs/ocfs2/namei.c > +++ b/fs/ocfs2/namei.c > @@ -566,7 +566,7 @@ static int __ocfs2_mknod_locked(struct inode *dir, > fe->i_last_eb_blk = 0; > strcpy(fe->i_signature, OCFS2_INODE_SIGNATURE); > fe->i_flags |= cpu_to_le32(OCFS2_VALID_FL); > - ktime_get_real_ts64(&ts); > + ktime_get_coarse_real_ts64(&ts); > fe->i_atime = fe->i_ctime = fe->i_mtime = > cpu_to_le64(ts.tv_sec); > fe->i_mtime_nsec = fe->i_ctime_nsec = fe->i_atime_nsec =
diff --git a/fs/ocfs2/namei.c b/fs/ocfs2/namei.c index 55c9d90caaaf..4d1ea8703fcd 100644 --- a/fs/ocfs2/namei.c +++ b/fs/ocfs2/namei.c @@ -566,7 +566,7 @@ static int __ocfs2_mknod_locked(struct inode *dir, fe->i_last_eb_blk = 0; strcpy(fe->i_signature, OCFS2_INODE_SIGNATURE); fe->i_flags |= cpu_to_le32(OCFS2_VALID_FL); - ktime_get_real_ts64(&ts); + ktime_get_coarse_real_ts64(&ts); fe->i_atime = fe->i_ctime = fe->i_mtime = cpu_to_le64(ts.tv_sec); fe->i_mtime_nsec = fe->i_ctime_nsec = fe->i_atime_nsec =