[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>

fs/xfs/linux-2.6/xfs_iops.c

@@ -57,6 +57,24 @@
 #define IS_NOATIME(inode) ((inode->i_sb->s_flags & MS_NOATIME) ||	\
 	(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
@@ -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(
@@ -141,32 +140,23 @@ 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) {
 		tvp = &inode->i_mtime;
 		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;

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;
 }
 

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;

fs/xfs/xfs_inode.c

@@ -3364,6 +3364,11 @@ xfs_iflush_int(
 	ip->i_update_core = 0;
 	SYNCHRONIZE();
 
+	/*
+	 * Make sure to get the latest atime from the Linux inode.
+	 */
+	xfs_synchronize_atime(ip);
+
 	if (XFS_TEST_ERROR(INT_GET(dip->di_core.di_magic,ARCH_CONVERT) != XFS_DINODE_MAGIC,
 			       mp, XFS_ERRTAG_IFLUSH_1, XFS_RANDOM_IFLUSH_1)) {
 		xfs_cmn_err(XFS_PTAG_IFLUSH, CE_ALERT, mp,

fs/xfs/xfs_inode.h

@@ -436,6 +436,8 @@ void		xfs_ichgtime(xfs_inode_t *, int);
 xfs_fsize_t	xfs_file_last_byte(xfs_inode_t *);
 void		xfs_lock_inodes(xfs_inode_t **, int, int, uint);
 
+void		xfs_synchronize_atime(xfs_inode_t *);
+
 #define xfs_ipincount(ip)	((unsigned int) atomic_read(&ip->i_pincount))
 
 #ifdef DEBUG

fs/xfs/xfs_inode_item.c

@@ -271,6 +271,11 @@ xfs_inode_item_format(
 	if (ip->i_update_size)
 		ip->i_update_size = 0;
 
+	/*
+	 * Make sure to get the latest atime from the Linux inode.
+	 */
+	xfs_synchronize_atime(ip);
+
 	vecp->i_addr = (xfs_caddr_t)&ip->i_d;
 	vecp->i_len  = sizeof(xfs_dinode_core_t);
 	XLOG_VEC_SET_TYPE(vecp, XLOG_REG_TYPE_ICORE);

fs/xfs/xfs_itable.c

@@ -56,6 +56,7 @@ xfs_bulkstat_one_iget(
 {
 	xfs_dinode_core_t *dic;		/* dinode core info pointer */
 	xfs_inode_t	*ip;		/* incore inode pointer */
+	vnode_t		*vp;
 	int		error;
 
 	error = xfs_iget(mp, NULL, ino, 0, XFS_ILOCK_SHARED, &ip, bno);
@@ -72,6 +73,7 @@ xfs_bulkstat_one_iget(
 		goto out_iput;
 	}
 
+	vp = XFS_ITOV(ip);
 	dic = &ip->i_d;
 
 	/* xfs_iget returns the following without needing
@@ -84,8 +86,9 @@ xfs_bulkstat_one_iget(
 	buf->bs_uid = dic->di_uid;
 	buf->bs_gid = dic->di_gid;
 	buf->bs_size = dic->di_size;
-	buf->bs_atime.tv_sec = dic->di_atime.t_sec;
-	buf->bs_atime.tv_nsec = dic->di_atime.t_nsec;
+	/* atime is only kept uptodate in the Linux inode */
+	buf->bs_atime.tv_sec = vp->v_inode.i_atime.tv_sec;
+	buf->bs_atime.tv_nsec = vp->v_inode.i_atime.tv_nsec;
 	buf->bs_mtime.tv_sec = dic->di_mtime.t_sec;
 	buf->bs_mtime.tv_nsec = dic->di_mtime.t_nsec;
 	buf->bs_ctime.tv_sec = dic->di_ctime.t_sec;

fs/xfs/xfs_vnodeops.c

@@ -182,8 +182,8 @@ xfs_getattr(
 		break;
 	}
 
-	vap->va_atime.tv_sec = ip->i_d.di_atime.t_sec;
-	vap->va_atime.tv_nsec = ip->i_d.di_atime.t_nsec;
+	/* atime is only kept uptodate in the Linux inode */
+	vap->va_atime = vp->v_inode.i_atime;
 	vap->va_mtime.tv_sec = ip->i_d.di_mtime.t_sec;
 	vap->va_mtime.tv_nsec = ip->i_d.di_mtime.t_nsec;
 	vap->va_ctime.tv_sec = ip->i_d.di_ctime.t_sec;
@@ -982,10 +982,6 @@ xfs_readlink(
 		goto error_return;
 	}
 
-	if (!(ioflags & IO_INVIS)) {
-		xfs_ichgtime(ip, XFS_ICHGTIME_ACC);
-	}
-
 	/*
 	 * See if the symlink is stored inline.
 	 */
@@ -3226,7 +3222,6 @@ xfs_readdir(
 	xfs_trans_t	*tp = NULL;
 	int		error = 0;
 	uint		lock_mode;
-	xfs_off_t	start_offset;
 
 	vn_trace_entry(BHV_TO_VNODE(dir_bdp), __FUNCTION__,
 					       (inst_t *)__return_address);
@@ -3237,11 +3232,7 @@ xfs_readdir(
 	}
 
 	lock_mode = xfs_ilock_map_shared(dp);
-	start_offset = uiop->uio_offset;
 	error = XFS_DIR_GETDENTS(dp->i_mount, tp, dp, uiop, eofp);
-	if (start_offset != uiop->uio_offset) {
-		xfs_ichgtime(dp, XFS_ICHGTIME_ACC);
-	}
 	xfs_iunlock_map_shared(dp, lock_mode);
 	return error;
 }
@@ -3819,6 +3810,12 @@ xfs_reclaim(
 
 	ASSERT(XFS_FORCED_SHUTDOWN(ip->i_mount) || ip->i_delayed_blks == 0);
 
+	/*
+	 * Make sure the atime in the XFS inode is correct before freeing the
+	 * Linux inode.
+	 */
+	xfs_synchronize_atime(ip);
+
 	/* If we have nothing to flush with this inode then complete the
 	 * teardown now, otherwise break the link between the xfs inode
 	 * and the linux inode and clean up the xfs inode later. This