Re: [PATCH-v4 1/7] vfs: split update_time() into update_time() and write_time()

["Theodore Ts'o" <tytso@mit.edu>]

Christoph, can you take a quick look at this?  I'm not sure I got the
xfs inode transaction logging correct.

Thanks!!

						- Ted

commit cd58addfa340c9cf88b1f9b2d31a42e2e65c7252
Author: Theodore Ts'o <tytso@mit.edu>
Date:   Thu Nov 27 10:14:27 2014 -0500

    vfs: split update_time() into update_time() and write_time()
    
    In preparation for adding support for the lazytime mount option, we
    need to be able to separate out the update_time() and write_time()
    inode operations.  Previously, only btrfs and xfs uses update_time().
    
    With this patch, btrfs only needs write_time(), and xfs uses
    update_time() to synchronize its on-disk and in-memory timestamps.
    
    Signed-off-by: Theodore Ts'o <tytso@mit.edu>
    Cc: xfs@oss.sgi.com
    Cc: linux-btrfs@vger.kernel.org
    Acked-by: David Sterba <dsterba@suse.cz>

diff --git a/include/linux/fs.h b/include/linux/fs.h
index f4b0ecd..befd5d2 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1545,7 +1545,8 @@ struct inode_operations {
 	int (*fiemap)(struct inode *, struct fiemap_extent_info *, u64 start,
 		      u64 len);
 	int (*is_readonly)(struct inode *);
-	int (*update_time)(struct inode *, struct timespec *, int);
+	void (*update_time)(struct inode *);
+	int (*write_time)(struct inode *);
 	int (*atomic_open)(struct inode *, struct dentry *,
 			   struct file *, unsigned open_flag,
 			   umode_t create_mode, int *opened);
diff --git a/fs/inode.c b/fs/inode.c
index 53f0173..94bc908 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -1506,9 +1506,6 @@ static int update_time(struct inode *inode, struct timespec *time, int flags)
  		if (ret)
  			return ret;
 	}
-	if (inode->i_op->update_time)
-		return inode->i_op->update_time(inode, time, flags);
-
 	if (flags & S_ATIME)
 		inode->i_atime = *time;
 	if (flags & S_VERSION)
@@ -1517,6 +1514,10 @@ static int update_time(struct inode *inode, struct timespec *time, int flags)
 		inode->i_ctime = *time;
 	if (flags & S_MTIME)
 		inode->i_mtime = *time;
+	if (inode->i_op->update_time)
+		inode->i_op->update_time(inode);
+	if (inode->i_op->write_time)
+		return inode->i_op->write_time(inode);
 	mark_inode_dirty_sync(inode);
 	return 0;
 }
diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c
index ec6dcdc..b69493d 100644
--- a/fs/xfs/xfs_iops.c
+++ b/fs/xfs/xfs_iops.c
@@ -983,42 +983,42 @@ xfs_vn_setattr(
 	return error;
 }
 
-STATIC int
+STATIC void
 xfs_vn_update_time(
-	struct inode		*inode,
-	struct timespec		*now,
-	int			flags)
+	struct inode		*inode)
+{
+	struct xfs_inode	*ip = XFS_I(inode);
+
+	trace_xfs_update_time(ip);
+	xfs_ilock(ip, XFS_ILOCK_EXCL);
+	ip->i_d.di_ctime.t_sec = (__int32_t) inode->i_ctime.tv_sec;
+	ip->i_d.di_ctime.t_nsec = (__int32_t) inode->i_ctime.tv_nsec;
+
+	ip->i_d.di_mtime.t_sec = (__int32_t)inode->i_mtime.tv_sec;
+	ip->i_d.di_mtime.t_nsec = (__int32_t) inode->i_mtime.tv_nsec;
+
+	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;
+	xfs_iunlock(ip, XFS_ILOCK_EXCL);
+}
+
+STATIC int
+xfs_vn_write_time(
+	struct inode		*inode)
 {
 	struct xfs_inode	*ip = XFS_I(inode);
 	struct xfs_mount	*mp = ip->i_mount;
 	struct xfs_trans	*tp;
 	int			error;
 
-	trace_xfs_update_time(ip);
-
+	trace_xfs_write_time(ip);
 	tp = xfs_trans_alloc(mp, XFS_TRANS_FSYNC_TS);
 	error = xfs_trans_reserve(tp, &M_RES(mp)->tr_fsyncts, 0, 0);
 	if (error) {
 		xfs_trans_cancel(tp, 0);
 		return error;
 	}
-
 	xfs_ilock(ip, XFS_ILOCK_EXCL);
-	if (flags & S_CTIME) {
-		inode->i_ctime = *now;
-		ip->i_d.di_ctime.t_sec = (__int32_t)now->tv_sec;
-		ip->i_d.di_ctime.t_nsec = (__int32_t)now->tv_nsec;
-	}
-	if (flags & S_MTIME) {
-		inode->i_mtime = *now;
-		ip->i_d.di_mtime.t_sec = (__int32_t)now->tv_sec;
-		ip->i_d.di_mtime.t_nsec = (__int32_t)now->tv_nsec;
-	}
-	if (flags & S_ATIME) {
-		inode->i_atime = *now;
-		ip->i_d.di_atime.t_sec = (__int32_t)now->tv_sec;
-		ip->i_d.di_atime.t_nsec = (__int32_t)now->tv_nsec;
-	}
 	xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
 	xfs_trans_log_inode(tp, ip, XFS_ILOG_TIMESTAMP);
 	return xfs_trans_commit(tp, 0);
@@ -1130,6 +1130,7 @@ static const struct inode_operations xfs_inode_operations = {
 	.listxattr		= xfs_vn_listxattr,
 	.fiemap			= xfs_vn_fiemap,
 	.update_time		= xfs_vn_update_time,
+	.write_time		= xfs_vn_write_time,
 };
 
 static const struct inode_operations xfs_dir_inode_operations = {
@@ -1157,6 +1158,7 @@ static const struct inode_operations xfs_dir_inode_operations = {
 	.removexattr		= generic_removexattr,
 	.listxattr		= xfs_vn_listxattr,
 	.update_time		= xfs_vn_update_time,
+	.write_time		= xfs_vn_write_time,
 	.tmpfile		= xfs_vn_tmpfile,
 };
 
@@ -1185,6 +1187,7 @@ static const struct inode_operations xfs_dir_ci_inode_operations = {
 	.removexattr		= generic_removexattr,
 	.listxattr		= xfs_vn_listxattr,
 	.update_time		= xfs_vn_update_time,
+	.write_time		= xfs_vn_write_time,
 	.tmpfile		= xfs_vn_tmpfile,
 };
 
@@ -1199,6 +1202,7 @@ static const struct inode_operations xfs_symlink_inode_operations = {
 	.removexattr		= generic_removexattr,
 	.listxattr		= xfs_vn_listxattr,
 	.update_time		= xfs_vn_update_time,
+	.write_time		= xfs_vn_write_time,
 };
 
 STATIC void
diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h
index 51372e3..09d261c 100644
--- a/fs/xfs/xfs_trace.h
+++ b/fs/xfs/xfs_trace.h
@@ -677,6 +677,7 @@ DEFINE_INODE_EVENT(xfs_file_fsync);
 DEFINE_INODE_EVENT(xfs_destroy_inode);
 DEFINE_INODE_EVENT(xfs_evict_inode);
 DEFINE_INODE_EVENT(xfs_update_time);
+DEFINE_INODE_EVENT(xfs_write_time);
 
 DEFINE_INODE_EVENT(xfs_dquot_dqalloc);
 DEFINE_INODE_EVENT(xfs_dquot_dqdetach);
diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking
index b30753c..ee94a66 100644
--- a/Documentation/filesystems/Locking
+++ b/Documentation/filesystems/Locking
@@ -62,7 +62,8 @@ prototypes:
 	ssize_t (*listxattr) (struct dentry *, char *, size_t);
 	int (*removexattr) (struct dentry *, const char *);
 	int (*fiemap)(struct inode *, struct fiemap_extent_info *, u64 start, u64 len);
-	void (*update_time)(struct inode *, struct timespec *, int);
+	void (*update_time)(struct inode *);
+	void (*write_time)(struct inode *);
 	int (*atomic_open)(struct inode *, struct dentry *,
 				struct file *, unsigned open_flag,
 				umode_t create_mode, int *opened);
@@ -95,6 +96,7 @@ listxattr:	no
 removexattr:	yes
 fiemap:		no
 update_time:	no
+write_time:	no
 atomic_open:	yes
 tmpfile:	no
 dentry_open:	no
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index bd46a22..a81a0652 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -5563,26 +5563,8 @@ static int btrfs_is_readonly(struct inode *inode)
 	return 0;
 }
 
-/*
- * This is a copy of file_update_time.  We need this so we can return error on
- * ENOSPC for updating the inode in the case of file write and mmap writes.
- */
-static int btrfs_update_time(struct inode *inode, struct timespec *now,
-			     int flags)
+static int btrfs_write_time(struct inode *inode)
 {
-	struct btrfs_root *root = BTRFS_I(inode)->root;
-
-	if (btrfs_root_readonly(root))
-		return -EROFS;
-
-	if (flags & S_VERSION)
-		inode_inc_iversion(inode);
-	if (flags & S_CTIME)
-		inode->i_ctime = *now;
-	if (flags & S_MTIME)
-		inode->i_mtime = *now;
-	if (flags & S_ATIME)
-		inode->i_atime = *now;
 	return btrfs_dirty_inode(inode);
 }
 
@@ -9471,7 +9453,7 @@ static const struct inode_operations btrfs_dir_inode_operations = {
 	.get_acl	= btrfs_get_acl,
 	.set_acl	= btrfs_set_acl,
 	.is_readonly	= btrfs_is_readonly,
-	.update_time	= btrfs_update_time,
+	.write_time	= btrfs_write_time,
 	.tmpfile        = btrfs_tmpfile,
 };
 static const struct inode_operations btrfs_dir_ro_inode_operations = {
@@ -9480,7 +9462,7 @@ static const struct inode_operations btrfs_dir_ro_inode_operations = {
 	.get_acl	= btrfs_get_acl,
 	.set_acl	= btrfs_set_acl,
 	.is_readonly	= btrfs_is_readonly,
-	.update_time	= btrfs_update_time,
+	.write_time	= btrfs_write_time,
 };
 
 static const struct file_operations btrfs_dir_file_operations = {
@@ -9551,7 +9533,7 @@ static const struct inode_operations btrfs_file_inode_operations = {
 	.get_acl	= btrfs_get_acl,
 	.set_acl	= btrfs_set_acl,
 	.is_readonly	= btrfs_is_readonly,
-	.update_time	= btrfs_update_time,
+	.write_time	= btrfs_write_time,
 };
 static const struct inode_operations btrfs_special_inode_operations = {
 	.getattr	= btrfs_getattr,
@@ -9564,7 +9546,7 @@ static const struct inode_operations btrfs_special_inode_operations = {
 	.get_acl	= btrfs_get_acl,
 	.set_acl	= btrfs_set_acl,
 	.is_readonly	= btrfs_is_readonly,
-	.update_time	= btrfs_update_time,
+	.write_time	= btrfs_write_time,
 };
 static const struct inode_operations btrfs_symlink_inode_operations = {
 	.readlink	= generic_readlink,
@@ -9578,7 +9560,7 @@ static const struct inode_operations btrfs_symlink_inode_operations = {
 	.listxattr	= btrfs_listxattr,
 	.removexattr	= btrfs_removexattr,
 	.is_readonly	= btrfs_is_readonly,
-	.update_time	= btrfs_update_time,
+	.write_time	= btrfs_write_time,
 };
 
 const struct dentry_operations btrfs_dentry_operations = {