[XFS] fix, speedup and simplify atime handling let the VFS handle atime

updates and only sync back to the xfs inode when nessecary

SGI-PV: 946679
SGI-Modid: xfs-linux-melb:xfs-kern:203362a

Signed-off-by: Christoph Hellwig <hch@sgi.com>
Signed-off-by: Nathan Scott <nathans@sgi.com>

3 files changed, 24 insertions, 41 deletions

diff --git a/fs/xfs/linux-2.6/xfs_iops.c b/fs/xfs/linux-2.6/xfs_iops.c
index 97fb147..8fd274f 100644
--- a/fs/xfs/linux-2.6/xfs_iops.c
+++ b/fs/xfs/linux-2.6/xfs_iops.c
@@ -58,6 +58,24 @@
 	(S_ISDIR(inode->i_mode) && inode->i_sb->s_flags & MS_NODIRATIME))
 
 /*
+ * Bring the atime in the XFS inode uptodate.
+ * Used before logging the inode to disk or when the Linux inode goes away.
+ */
+void
+xfs_synchronize_atime(
+	xfs_inode_t	*ip)
+{
+	vnode_t		*vp;
+
+	vp = XFS_ITOV_NULL(ip);
+	if (vp) {
+		struct inode *inode = &vp->v_inode;
+		ip->i_d.di_atime.t_sec = (__int32_t)inode->i_atime.tv_sec;
+		ip->i_d.di_atime.t_nsec = (__int32_t)inode->i_atime.tv_nsec;
+	}
+}
+
+/*
  * Change the requested timestamp in the given inode.
  * We don't lock across timestamp updates, and we don't log them but
  * we do record the fact that there is dirty information in core.
@@ -76,23 +94,6 @@ xfs_ichgtime(
 	struct inode	*inode = LINVFS_GET_IP(XFS_ITOV(ip));
 	timespec_t	tv;
 
-	/*
-	 * We're not supposed to change timestamps in readonly-mounted
-	 * filesystems.  Throw it away if anyone asks us.
-	 */
-	if (unlikely(IS_RDONLY(inode)))
-		return;
-
-	/*
-	 * Don't update access timestamps on reads if mounted "noatime".
-	 * Throw it away if anyone asks us.
-	 */
-	if (unlikely(
-	    (ip->i_mount->m_flags & XFS_MOUNT_NOATIME || IS_NOATIME(inode)) &&
-	    (flags & (XFS_ICHGTIME_ACC|XFS_ICHGTIME_MOD|XFS_ICHGTIME_CHG)) ==
-			XFS_ICHGTIME_ACC))
-		return;
-
 	nanotime(&tv);
 	if (flags & XFS_ICHGTIME_MOD) {
 		inode->i_mtime = tv;
@@ -129,8 +130,6 @@ xfs_ichgtime(
  * Variant on the above which avoids querying the system clock
  * in situations where we know the Linux inode timestamps have
  * just been updated (and so we can update our inode cheaply).
- * We also skip the readonly and noatime checks here, they are
- * also catered for already.
  */
 void
 xfs_ichgtime_fast(
@@ -141,20 +140,16 @@ xfs_ichgtime_fast(
 	timespec_t	*tvp;
 
 	/*
-	 * We're not supposed to change timestamps in readonly-mounted
-	 * filesystems.  Throw it away if anyone asks us.
+	 * Atime updates for read() & friends are handled lazily now, and
+	 * explicit updates must go through xfs_ichgtime()
 	 */
-	if (unlikely(IS_RDONLY(inode)))
-		return;
+	ASSERT((flags & XFS_ICHGTIME_ACC) == 0);
 
 	/*
-	 * Don't update access timestamps on reads if mounted "noatime".
-	 * Throw it away if anyone asks us.
+	 * We're not supposed to change timestamps in readonly-mounted
+	 * filesystems.  Throw it away if anyone asks us.
 	 */
-	if (unlikely(
-	    (ip->i_mount->m_flags & XFS_MOUNT_NOATIME || IS_NOATIME(inode)) &&
-	    ((flags & (XFS_ICHGTIME_ACC|XFS_ICHGTIME_MOD|XFS_ICHGTIME_CHG)) ==
-			XFS_ICHGTIME_ACC)))
+	if (unlikely(IS_RDONLY(inode)))
 		return;
 
 	if (flags & XFS_ICHGTIME_MOD) {
@@ -162,11 +157,6 @@ xfs_ichgtime_fast(
 		ip->i_d.di_mtime.t_sec = (__int32_t)tvp->tv_sec;
 		ip->i_d.di_mtime.t_nsec = (__int32_t)tvp->tv_nsec;
 	}
-	if (flags & XFS_ICHGTIME_ACC) {
-		tvp = &inode->i_atime;
-		ip->i_d.di_atime.t_sec = (__int32_t)tvp->tv_sec;
-		ip->i_d.di_atime.t_nsec = (__int32_t)tvp->tv_nsec;
-	}
 	if (flags & XFS_ICHGTIME_CHG) {
 		tvp = &inode->i_ctime;
 		ip->i_d.di_ctime.t_sec = (__int32_t)tvp->tv_sec;
diff --git a/fs/xfs/linux-2.6/xfs_lrw.c b/fs/xfs/linux-2.6/xfs_lrw.c
index c73d3c1..563cb9e 100644
--- a/fs/xfs/linux-2.6/xfs_lrw.c
+++ b/fs/xfs/linux-2.6/xfs_lrw.c
@@ -281,9 +281,6 @@ xfs_read(
 
 	xfs_iunlock(ip, XFS_IOLOCK_SHARED);
 
-	if (likely(!(ioflags & IO_INVIS)))
-		xfs_ichgtime_fast(ip, inode, XFS_ICHGTIME_ACC);
-
 unlock_isem:
 	if (unlikely(ioflags & IO_ISDIRECT))
 		mutex_unlock(&inode->i_mutex);
@@ -346,9 +343,6 @@ xfs_sendfile(
 	if (ret > 0)
 		XFS_STATS_ADD(xs_read_bytes, ret);
 
-	if (likely(!(ioflags & IO_INVIS)))
-		xfs_ichgtime_fast(ip, LINVFS_GET_IP(vp), XFS_ICHGTIME_ACC);
-
 	return ret;
 }
 
diff --git a/fs/xfs/linux-2.6/xfs_vnode.c b/fs/xfs/linux-2.6/xfs_vnode.c
index e9bbcb4..260dd84 100644
--- a/fs/xfs/linux-2.6/xfs_vnode.c
+++ b/fs/xfs/linux-2.6/xfs_vnode.c
@@ -106,7 +106,6 @@ vn_revalidate_core(
 	inode->i_blocks	    = vap->va_nblocks;
 	inode->i_mtime	    = vap->va_mtime;
 	inode->i_ctime	    = vap->va_ctime;
-	inode->i_atime	    = vap->va_atime;
 	inode->i_blksize    = vap->va_blocksize;
 	if (vap->va_xflags & XFS_XFLAG_IMMUTABLE)
 		inode->i_flags |= S_IMMUTABLE;