[PATCH] per-mountpoint noatime/nodiratime

Turn noatime and nodiratime into per-mount instead of per-sb flags.

After all the preparations this is a rather trivial patch.  The mount code
needs to treat the two options as per-mount instead of per-superblock, and
touch_atime needs to be changed to check the new MNT_ flags in addition to
the MS_ flags that are kept for filesystems that are always
noatime/nodiratime but not user settable anymore.  Besides that core code
only nfs needed an update because it's leaving atime updates to the server
and thus sets the S_NOATIME flag on every inode, but needs to know whether
it's a real noatime mount for an getattr optimization.

While we're at it I've killed the IS_NOATIME/IS_NODIRATIME macros that were
only used by touch_atime.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

4 files changed, 38 insertions, 11 deletions

diff --git a/fs/inode.c b/fs/inode.c
index 76980a9..108138d 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -22,6 +22,7 @@
 #include <linux/cdev.h>
 #include <linux/bootmem.h>
 #include <linux/inotify.h>
+#include <linux/mount.h>
 
 /*
  * This is needed for the following functions:
@@ -1189,12 +1190,20 @@ void touch_atime(struct vfsmount *mnt, struct dentry *dentry)
 	struct inode *inode = dentry->d_inode;
 	struct timespec now;
 
-	/* per-mountpoint checks will go here */
-	if (IS_NOATIME(inode))
+	if (IS_RDONLY(inode))
 		return;
-	if (IS_NODIRATIME(inode) && S_ISDIR(inode->i_mode))
+
+	if ((inode->i_flags & S_NOATIME) ||
+	    (inode->i_sb->s_flags & MS_NOATIME) ||
+	    ((inode->i_sb->s_flags & MS_NODIRATIME) && S_ISDIR(inode->i_mode)))
 		return;
-	if (IS_RDONLY(inode))
+
+	/*
+	 * We may have a NULL vfsmount when coming from NFSD
+	 */
+	if (mnt &&
+	    ((mnt->mnt_flags & MNT_NOATIME) ||
+	     ((mnt->mnt_flags & MNT_NODIRATIME) && S_ISDIR(inode->i_mode))))
 		return;
 
 	now = current_fs_time(inode->i_sb);
diff --git a/fs/namespace.c b/fs/namespace.c
index f0e353f..2ca6145 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -355,14 +355,14 @@ static int show_vfsmnt(struct seq_file *m, void *v)
 		{ MS_SYNCHRONOUS, ",sync" },
 		{ MS_DIRSYNC, ",dirsync" },
 		{ MS_MANDLOCK, ",mand" },
-		{ MS_NOATIME, ",noatime" },
-		{ MS_NODIRATIME, ",nodiratime" },
 		{ 0, NULL }
 	};
 	static struct proc_fs_info mnt_info[] = {
 		{ MNT_NOSUID, ",nosuid" },
 		{ MNT_NODEV, ",nodev" },
 		{ MNT_NOEXEC, ",noexec" },
+		{ MNT_NOATIME, ",noatime" },
+		{ MNT_NODIRATIME, ",nodiratime" },
 		{ 0, NULL }
 	};
 	struct proc_fs_info *fs_infop;
@@ -1286,7 +1286,13 @@ long do_mount(char *dev_name, char *dir_name, char *type_page,
 		mnt_flags |= MNT_NODEV;
 	if (flags & MS_NOEXEC)
 		mnt_flags |= MNT_NOEXEC;
-	flags &= ~(MS_NOSUID | MS_NOEXEC | MS_NODEV | MS_ACTIVE);
+	if (flags & MS_NOATIME)
+		mnt_flags |= MNT_NOATIME;
+	if (flags & MS_NODIRATIME)
+		mnt_flags |= MNT_NODIRATIME;
+
+	flags &= ~(MS_NOSUID | MS_NOEXEC | MS_NODEV | MS_ACTIVE |
+		   MS_NOATIME | MS_NODIRATIME);
 
 	/* ... and get the mountpoint */
 	retval = path_lookup(dir_name, LOOKUP_FOLLOW, &nd);
diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index 3e4ba9c..a77ee95 100644
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -950,11 +950,20 @@ int nfs_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
 
 	/* Flush out writes to the server in order to update c/mtime */
 	nfs_sync_inode(inode, 0, 0, FLUSH_WAIT|FLUSH_NOCOMMIT);
-	if (__IS_FLG(inode, MS_NOATIME))
-		need_atime = 0;
-	else if (__IS_FLG(inode, MS_NODIRATIME) && S_ISDIR(inode->i_mode))
+
+	/*
+	 * We may force a getattr if the user cares about atime.
+	 *
+	 * Note that we only have to check the vfsmount flags here:
+	 *  - NFS always sets S_NOATIME by so checking it would give a
+	 *    bogus result
+	 *  - NFS never sets MS_NOATIME or MS_NODIRATIME so there is
+	 *    no point in checking those.
+	 */
+ 	if ((mnt->mnt_flags & MNT_NOATIME) ||
+ 	    ((mnt->mnt_flags & MNT_NODIRATIME) && S_ISDIR(inode->i_mode)))
 		need_atime = 0;
-	/* We may force a getattr if the user cares about atime */
+
 	if (need_atime)
 		err = __nfs_revalidate_inode(NFS_SERVER(inode), inode);
 	else
diff --git a/fs/xfs/linux-2.6/xfs_iops.c b/fs/xfs/linux-2.6/xfs_iops.c
index 41c478b..97fb147 100644
--- a/fs/xfs/linux-2.6/xfs_iops.c
+++ b/fs/xfs/linux-2.6/xfs_iops.c
@@ -54,6 +54,9 @@
 #include <linux/xattr.h>
 #include <linux/namei.h>
 
+#define IS_NOATIME(inode) ((inode->i_sb->s_flags & MS_NOATIME) ||	\
+	(S_ISDIR(inode->i_mode) && inode->i_sb->s_flags & MS_NODIRATIME))
+
 /*
  * Change the requested timestamp in the given inode.
  * We don't lock across timestamp updates, and we don't log them but