| Message ID | 20240402014651.13723-5-glass.su@suse.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | ocfs2 bugs fixes exposed by fstests | expand |
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 =
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. Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com> Signed-off-by: Su Yue <glass.su@suse.com> --- fs/ocfs2/namei.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)