2 files changed, 46 insertions, 12 deletions

diff --git a/fs/inode.c b/fs/inode.c
index 826fb0b9d1c3..6ac0cef6c5f5 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -1290,6 +1290,40 @@ sector_t bmap(struct inode * inode, sector_t block)
 }
 EXPORT_SYMBOL(bmap);
 
+/*
+ * With relative atime, only update atime if the previous atime is
+ * earlier than either the ctime or mtime or if at least a day has
+ * passed since the last atime update.
+ */
+static int relatime_need_update(struct vfsmount *mnt, struct inode *inode,
+                             struct timespec now)
+{
+
+        if (!(mnt->mnt_flags & MNT_RELATIME))
+                return 1;
+        /*
+         * Is mtime younger than atime? If yes, update atime:
+         */
+        if (timespec_compare(&inode->i_mtime, &inode->i_atime) >= 0)
+                return 1;
+        /*
+         * Is ctime younger than atime? If yes, update atime:
+         */
+        if (timespec_compare(&inode->i_ctime, &inode->i_atime) >= 0)
+                return 1;
+
+        /*
+         * Is the previous atime value older than a day? If yes,
+         * update atime:
+         */
+        if ((long)(now.tv_sec - inode->i_atime.tv_sec) >= 24*60*60)
+                return 1;
+        /*
+         * Good, we can skip the atime update:
+         */
+        return 0;
+}
+
 /**
  *      touch_atime     -       update the access time
  *      @mnt: mount the inode is accessed on
@@ -1317,17 +1351,12 @@ void touch_atime(struct vfsmount *mnt, struct dentry *dentry)
                 goto out;
         if ((mnt->mnt_flags & MNT_NODIRATIME) && S_ISDIR(inode->i_mode))
                 goto out;
-        if (mnt->mnt_flags & MNT_RELATIME) {
-                /*
-                 * With relative atime, only update atime if the previous
-                 * atime is earlier than either the ctime or mtime.
-                 */
-                if (timespec_compare(&inode->i_mtime, &inode->i_atime) < 0 &&
-                    timespec_compare(&inode->i_ctime, &inode->i_atime) < 0)
-                        goto out;
-        }
 
         now = current_fs_time(inode->i_sb);
+
+        if (!relatime_need_update(mnt, inode, now))
+                goto out;
+
         if (timespec_equal(&inode->i_atime, &now))
                 goto out;
 
diff --git a/fs/namespace.c b/fs/namespace.c
index 06f8e63f6cb1..f0e753097353 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -780,6 +780,7 @@ static void show_mnt_opts(struct seq_file *m, struct vfsmount *mnt)
                 { MNT_NOATIME, ",noatime" },
                 { MNT_NODIRATIME, ",nodiratime" },
                 { MNT_RELATIME, ",relatime" },
+                { MNT_STRICTATIME, ",strictatime" },
                 { 0, NULL }
         };
         const struct proc_fs_info *fs_infop;
@@ -1919,6 +1920,9 @@ long do_mount(char *dev_name, char *dir_name, char *type_page,
         if (data_page)
                 ((char *)data_page)[PAGE_SIZE - 1] = 0;
 
+        /* Default to relatime */
+        mnt_flags |= MNT_RELATIME;
+
         /* Separate the per-mountpoint flags */
         if (flags & MS_NOSUID)
                 mnt_flags |= MNT_NOSUID;
@@ -1930,13 +1934,14 @@ long do_mount(char *dev_name, char *dir_name, char *type_page,
                 mnt_flags |= MNT_NOATIME;
         if (flags & MS_NODIRATIME)
                 mnt_flags |= MNT_NODIRATIME;
-        if (flags & MS_RELATIME)
-                mnt_flags |= MNT_RELATIME;
+        if (flags & MS_STRICTATIME)
+                mnt_flags &= ~(MNT_RELATIME | MNT_NOATIME);
         if (flags & MS_RDONLY)
                 mnt_flags |= MNT_READONLY;
 
         flags &= ~(MS_NOSUID | MS_NOEXEC | MS_NODEV | MS_ACTIVE |
-                   MS_NOATIME | MS_NODIRATIME | MS_RELATIME| MS_KERNMOUNT);
+                   MS_NOATIME | MS_NODIRATIME | MS_RELATIME| MS_KERNMOUNT |
+                   MS_STRICTATIME);
 
         /* ... and get the mountpoint */
         retval = kern_path(dir_name, LOOKUP_FOLLOW, &path);