xfs: fix timestamp handling in xfs_setattr

We currently have some rather odd code in xfs_setattr for updating the a/c/mtime timestampts:

- first we do a non-transaction update if all three are updated together
- second we implicitly update the ctime for various changes instead of relying on the ATTR_CTIME flag
- third we set the timestamps to the current time instead of the arguments in the iattr structure in many cases.

This patch makes sure we update it in a consistant way:

- always transactional
- ctime is only updated if ATTR_CTIME is set or we do a size update, which is a special case
- always to the times passed in from the caller instead of the current time

The only non-size caller of xfs_setattr that doesn't come from the VFS is updated to set ATTR_CTIME and pass in a valid ctime value.

Reported-by Eric Blake <[email protected]>

Signed-off-by Christoph Hellwig <[email protected]>

Index: linux-2.6/fs/xfs/xfs_vnodeops.c
===================================================================

fs/xfs/xfs_vnodeops.c +40 -55

@@ -70,7 +70,6 @@ xfs_setattr(
 	uint			commit_flags=0;
 	uid_t			uid=0, iuid=0;
 	gid_t			gid=0, igid=0;
-	int			timeflags = 0;
 	struct xfs_dquot	*udqp, *gdqp, *olddquot1, *olddquot2;
 	int			need_iolock = 1;
 

@@ -135,16 +134,13 @@ xfs_setattr(
 	if (flags & XFS_ATTR_NOLOCK)
 		need_iolock = 0;
 	if (!(mask & ATTR_SIZE)) {
-		if ((mask != (ATTR_CTIME|ATTR_ATIME|ATTR_MTIME)) ||
-		    (mp->m_flags & XFS_MOUNT_WSYNC)) {
-			tp = xfs_trans_alloc(mp, XFS_TRANS_SETATTR_NOT_SIZE);
-			commit_flags = 0;
-			if ((code = xfs_trans_reserve(tp, 0,
-						     XFS_ICHANGE_LOG_RES(mp), 0,
-						     0, 0))) {
-				lock_flags = 0;
-				goto error_return;
-			}
+		tp = xfs_trans_alloc(mp, XFS_TRANS_SETATTR_NOT_SIZE);
+		commit_flags = 0;
+		code = xfs_trans_reserve(tp, 0, XFS_ICHANGE_LOG_RES(mp),
+					 0, 0, 0);
+		if (code) {
+			lock_flags = 0;
+			goto error_return;
 		}
 	} else {
 		if (DM_EVENT_ENABLED(ip, DM_EVENT_TRUNCATE) &&

@@ -295,15 +291,23 @@ xfs_setattr(
 		 * or we are explicitly asked to change it. This handles
 		 * the semantic difference between truncate() and ftruncate()
 		 * as implemented in the VFS.
-		 */
-		if (iattr->ia_size != ip->i_size || (mask & ATTR_CTIME))
-			timeflags |= XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG;
+		 *
+		 * The regular truncate() case without ATTR_CTIME and ATTR_MTIME
+		 * is a special case where we need to update the times despite
+		 * not having these flags set.  For all other operations the
+		 * VFS set these flags explicitly if it wants a timestamp
+		 * update.
+		 */
+		if (iattr->ia_size != ip->i_size &&
+		    (!(mask & (ATTR_CTIME | ATTR_MTIME)))) {
+			iattr->ia_ctime = iattr->ia_mtime =
+				current_fs_time(inode->i_sb);
+			mask |= ATTR_CTIME | ATTR_MTIME;
+		}
 
 		if (iattr->ia_size > ip->i_size) {
 			ip->i_d.di_size = iattr->ia_size;
 			ip->i_size = iattr->ia_size;
-			if (!(flags & XFS_ATTR_DMI))
-				xfs_ichgtime(ip, XFS_ICHGTIME_CHG);
 			xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
 		} else if (iattr->ia_size <= ip->i_size ||
 			   (iattr->ia_size == 0 && ip->i_d.di_nextents)) {

@@ -374,9 +378,6 @@ xfs_setattr(
 			ip->i_d.di_gid = gid;
 			inode->i_gid = gid;
 		}
-
-		xfs_trans_log_inode (tp, ip, XFS_ILOG_CORE);
-		timeflags |= XFS_ICHGTIME_CHG;
 	}
 
 	/*

@@ -393,51 +394,37 @@ xfs_setattr(
 
 		inode->i_mode &= S_IFMT;
 		inode->i_mode |= mode & ~S_IFMT;
-
-		xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
-		timeflags |= XFS_ICHGTIME_CHG;
 	}
 
 	/*
 	 * Change file access or modified times.
 	 */
-	if (mask & (ATTR_ATIME|ATTR_MTIME)) {
-		if (mask & ATTR_ATIME) {
-			inode->i_atime = iattr->ia_atime;
-			ip->i_d.di_atime.t_sec = iattr->ia_atime.tv_sec;
-			ip->i_d.di_atime.t_nsec = iattr->ia_atime.tv_nsec;
-			ip->i_update_core = 1;
-		}
-		if (mask & ATTR_MTIME) {
-			inode->i_mtime = iattr->ia_mtime;
-			ip->i_d.di_mtime.t_sec = iattr->ia_mtime.tv_sec;
-			ip->i_d.di_mtime.t_nsec = iattr->ia_mtime.tv_nsec;
-			timeflags &= ~XFS_ICHGTIME_MOD;
-			timeflags |= XFS_ICHGTIME_CHG;
-		}
-		if (tp && (mask & (ATTR_MTIME_SET|ATTR_ATIME_SET)))
-			xfs_trans_log_inode (tp, ip, XFS_ILOG_CORE);
+	if (mask & ATTR_ATIME) {
+		inode->i_atime = iattr->ia_atime;
+		ip->i_d.di_atime.t_sec = iattr->ia_atime.tv_sec;
+		ip->i_d.di_atime.t_nsec = iattr->ia_atime.tv_nsec;
+		ip->i_update_core = 1;
 	}
-
-	/*
-	 * Change file inode change time only if ATTR_CTIME set
-	 * AND we have been called by a DMI function.
-	 */
-
-	if ((flags & XFS_ATTR_DMI) && (mask & ATTR_CTIME)) {
+	if (mask & ATTR_CTIME) {
 		inode->i_ctime = iattr->ia_ctime;
 		ip->i_d.di_ctime.t_sec = iattr->ia_ctime.tv_sec;
 		ip->i_d.di_ctime.t_nsec = iattr->ia_ctime.tv_nsec;
 		ip->i_update_core = 1;
-		timeflags &= ~XFS_ICHGTIME_CHG;
+	}
+	if (mask & ATTR_MTIME) {
+		inode->i_mtime = iattr->ia_mtime;
+		ip->i_d.di_mtime.t_sec = iattr->ia_mtime.tv_sec;
+		ip->i_d.di_mtime.t_nsec = iattr->ia_mtime.tv_nsec;
+		ip->i_update_core = 1;
 	}
 
 	/*
-	 * Send out timestamp changes that need to be set to the
-	 * current time.  Not done when called by a DMI function.
+	 * And finally, log the inode core if any attribute in it
+	 * has been changed.
 	 */
-	if (timeflags && !(flags & XFS_ATTR_DMI))
-		xfs_ichgtime(ip, timeflags);
+	if (mask & (ATTR_UID|ATTR_GID|ATTR_MODE|
+		    ATTR_ATIME|ATTR_CTIME|ATTR_MTIME))
+		xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
 
 	XFS_STATS_INC(xs_ig_attrchg);
 

@@ -452,12 +439,10 @@ xfs_setattr(
 	 * mix so this probably isn't worth the trouble to optimize.
 	 */
 	code = 0;
-	if (tp) {
-		if (mp->m_flags & XFS_MOUNT_WSYNC)
-			xfs_trans_set_sync(tp);
+	if (mp->m_flags & XFS_MOUNT_WSYNC)
+		xfs_trans_set_sync(tp);
 
-		code = xfs_trans_commit(tp, commit_flags);
-	}
+	code = xfs_trans_commit(tp, commit_flags);
 
 	xfs_iunlock(ip, lock_flags);
 

Index: linux-2.6/fs/xfs/linux-2.6/xfs_acl.c
===================================================================

fs/xfs/linux-2.6/xfs_acl.c +2 -1

@@ -251,8 +251,9 @@ xfs_set_mode(struct inode *inode, mode_t
 	if (mode != inode->i_mode) {
 		struct iattr iattr;
 
-		iattr.ia_valid = ATTR_MODE;
+		iattr.ia_valid = ATTR_MODE | ATTR_CTIME;
 		iattr.ia_mode = mode;
+		iattr.ia_ctime = current_fs_time(inode->i_sb);
 
 		error = -xfs_setattr(XFS_I(inode), &iattr, XFS_ATTR_NOACL);
 	}

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This looks good to me, although I acknowledge I haven't worked through it 100%. Another reviewer would be good. But even better, I really want to see the gnulib timestamp unit tests into xfstests to verify the behavior either way (which you indicated you'd work on...). In fact, if you've made any headway on it I'd like to run the tests against this patch before committing it.