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authorSu Yue <glass.su@suse.com>2024-04-08 16:20:41 +0800
committerAndrew Morton <akpm@linux-foundation.org>2024-04-25 21:07:07 -0700
commitb8cb324277ee16f3eca3055b96fce4735a5a41c6 (patch)
tree19565ddcf8639ca9bfe33a82903ee0edd532585d
parent8c40984eeb8804cffcd28640f427f4fe829243fc (diff)
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ocfs2: use coarse time for new created files
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 more accurate 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. Link: https://lkml.kernel.org/r/20240408082041.20925-5-glass.su@suse.com Fixes: c62c38f6b91b ("ocfs2: replace CURRENT_TIME macro") Signed-off-by: Su Yue <glass.su@suse.com> Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com> Cc: Mark Fasheh <mark@fasheh.com> Cc: Joel Becker <jlbec@evilplan.org> Cc: Junxiao Bi <junxiao.bi@oracle.com> Cc: Changwei Ge <gechangwei@live.cn> Cc: Gang He <ghe@suse.com> Cc: Jun Piao <piaojun@huawei.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
-rw-r--r--fs/ocfs2/namei.c2
1 files changed, 1 insertions, 1 deletions
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 =