tux3: Fix timestamp update for special files

Special files are updating timestamps without locking and
change_begin/end now.  This means, tux3 crashes at
tux3_mark_inode_dirty() because of no change_begin().

So, this adds ->update_time() handler to special files.

[FIXME: maybe, we should add lock for timestamp.]

And additionally, dir/symlink updates timestamps i_*time directly
(except i_atime), so this adds assertion in ->update_time() of
dir/symlink for debugging.

Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>

3 files changed, 58 insertions, 2 deletions

diff --git a/fs/tux3/inode.c b/fs/tux3/inode.c
index 1bfb28f3f5c18..ef9ceeb629b28 100644
--- a/fs/tux3/inode.c
+++ b/fs/tux3/inode.c
@@ -846,6 +846,9 @@ int tux3_setattr(struct dentry *dentry, struct iattr *iattr)
 	return err;
 }
 
+/*
+ * Timestamp handler for regular file.
+ */
 static int tux3_file_update_time(struct inode *inode, struct timespec *time,
 				 int flags)
 {
@@ -866,6 +869,55 @@ static int tux3_file_update_time(struct inode *inode, struct timespec *time,
 	return 0;
 }
 
+/*
+ * Timestamp handler for directory/symlink. Timestamp is updated by
+ * directly, so this should not be called except atime.
+ */
+int tux3_no_update_time(struct inode *inode, struct timespec *time, int flags)
+{
+	/* FIXME: atime is not supported yet */
+	if (flags & S_ATIME)
+		inode->i_atime = *time;
+	if (!(flags & ~S_ATIME))
+		return 0;
+
+	WARN(1, "update_time is called for inum %Lu, i_mode %x\n",
+	     tux_inode(inode)->inum, inode->i_mode);
+
+	return 0;
+}
+
+/*
+ * Timestamp handler for special file.  This is not called under
+ * change_{begin,end}() or ->i_mutex.
+ *
+ * FIXME: special file should also handle timestamp as transaction?
+ */
+static int tux3_special_update_time(struct inode *inode, struct timespec *time,
+				    int flags)
+{
+	struct sb *sb = tux_sb(inode->i_sb);
+
+	/* FIXME: atime is not supported yet */
+	if (flags & S_ATIME)
+		inode->i_atime = *time;
+	if (!(flags & ~S_ATIME))
+		return 0;
+
+	/* FIXME: no i_mutex, so this is racy */
+	change_begin(sb);
+	if (flags & S_VERSION)
+		inode_inc_iversion(inode);
+	if (flags & S_CTIME)
+		inode->i_ctime = *time;
+	if (flags & S_MTIME)
+		inode->i_mtime = *time;
+	mark_inode_dirty_sync(inode);
+	change_end(sb);
+
+	return 0;
+}
+
 #include "inode_vfslib.c"
 
 static const struct file_operations tux_file_fops = {
@@ -903,13 +955,14 @@ static const struct inode_operations tux_file_iops = {
 static const struct inode_operations tux_special_iops = {
 //	.permission	= ext4_permission,
 	.setattr	= tux3_setattr,
-	.getattr	= tux3_getattr
+	.getattr	= tux3_getattr,
 #ifdef CONFIG_EXT4DEV_FS_XATTR
 //	.setxattr	= generic_setxattr,
 //	.getxattr	= generic_getxattr,
 //	.listxattr	= ext4_listxattr,
 //	.removexattr	= generic_removexattr,
 #endif
+	.update_time	= tux3_special_update_time,
 };
 
 const struct inode_operations tux_symlink_iops = {
@@ -924,6 +977,7 @@ const struct inode_operations tux_symlink_iops = {
 //	.listxattr	= ext4_listxattr,
 //	.removexattr	= generic_removexattr,
 #endif
+	.update_time	= tux3_no_update_time,
 };
 
 static void tux_setup_inode(struct inode *inode)
diff --git a/fs/tux3/namei.c b/fs/tux3/namei.c
index 853c60377f166..4a7e9bf1ad318 100644
--- a/fs/tux3/namei.c
+++ b/fs/tux3/namei.c
@@ -358,7 +358,7 @@ const struct inode_operations tux_dir_iops = {
 	.mknod		= tux3_mknod,
 	.rename		= tux3_rename,
 	.setattr	= tux3_setattr,
-	.getattr	= tux3_getattr
+	.getattr	= tux3_getattr,
 //	.setxattr	= generic_setxattr,
 //	.getxattr	= generic_getxattr,
 //	.listxattr	= ext3_listxattr,
@@ -368,5 +368,6 @@ const struct inode_operations tux_dir_iops = {
 	/* FIXME: why doesn't ext4 support this for directory? */
 //	.fallocate	= ext4_fallocate,
 //	.fiemap		= ext4_fiemap,
+	.update_time	= tux3_no_update_time,
 };
 #endif /* !__KERNEL__ */
diff --git a/fs/tux3/tux3.h b/fs/tux3/tux3.h
index 002d6d47c38ea..a6bb78d161ab6 100644
--- a/fs/tux3/tux3.h
+++ b/fs/tux3/tux3.h
@@ -687,6 +687,7 @@ extern const struct address_space_operations tux_vol_aops;
 int tux3_sync_file(struct file *file, loff_t start, loff_t end, int datasync);
 int tux3_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat);
 int tux3_setattr(struct dentry *dentry, struct iattr *iattr);
+int tux3_no_update_time(struct inode *inode, struct timespec *time, int flags);
 
 /* symlink.c */
 extern const struct inode_operations tux_symlink_iops;