diff --git a/fs/inode.c b/fs/inode.c index 04536ebc5ac4..bf21dc6d0dbd 100644 --- a/fs/inode.c +++ b/fs/inode.c @@ -1177,13 +1177,27 @@ void touch_atime(struct vfsmount *mnt, struct dentry *dentry) return; if ((mnt->mnt_flags & MNT_NODIRATIME) && S_ISDIR(inode->i_mode)) return; + + 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) + return; + } } now = current_fs_time(inode->i_sb); - if (!timespec_equal(&inode->i_atime, &now)) { - inode->i_atime = now; - mark_inode_dirty_sync(inode); - } + if (timespec_equal(&inode->i_atime, &now)) + return; + + inode->i_atime = now; + mark_inode_dirty_sync(inode); } EXPORT_SYMBOL(touch_atime); diff --git a/fs/namespace.c b/fs/namespace.c index fde8553faa76..5ef336c1103c 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -368,6 +368,7 @@ static int show_vfsmnt(struct seq_file *m, void *v) { MNT_NOEXEC, ",noexec" }, { MNT_NOATIME, ",noatime" }, { MNT_NODIRATIME, ",nodiratime" }, + { MNT_RELATIME, ",relatime" }, { 0, NULL } }; struct proc_fs_info *fs_infop; @@ -1405,9 +1406,11 @@ 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; flags &= ~(MS_NOSUID | MS_NOEXEC | MS_NODEV | MS_ACTIVE | - MS_NOATIME | MS_NODIRATIME); + MS_NOATIME | MS_NODIRATIME | MS_RELATIME); /* ... and get the mountpoint */ retval = path_lookup(dir_name, LOOKUP_FOLLOW, &nd); diff --git a/include/linux/fs.h b/include/linux/fs.h index adce6e1d70c2..186da813541e 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -120,6 +120,7 @@ extern int dir_notify_enable; #define MS_PRIVATE (1<<18) /* change to private */ #define MS_SLAVE (1<<19) /* change to slave */ #define MS_SHARED (1<<20) /* change to shared */ +#define MS_RELATIME (1<<21) /* Update atime relative to mtime/ctime. */ #define MS_ACTIVE (1<<30) #define MS_NOUSER (1<<31) diff --git a/include/linux/mount.h b/include/linux/mount.h index e357dc86a4de..1b7e178b0d84 100644 --- a/include/linux/mount.h +++ b/include/linux/mount.h @@ -27,6 +27,7 @@ struct mnt_namespace; #define MNT_NOEXEC 0x04 #define MNT_NOATIME 0x08 #define MNT_NODIRATIME 0x10 +#define MNT_RELATIME 0x20 #define MNT_SHRINKABLE 0x100