[PATCH 13/25] ubifs: introduce a field named as budgeted to ubifs_inode

From: Dongsheng Yang <yangds.fnst@cn.fujitsu.com>
To: <dedekind1@gmail.com>, <richard.weinberger@gmail.com>, <jack@suse.com>
Cc: linux-fsdevel@vger.kernel.org,
	Dongsheng Yang <yangds.fnst@cn.fujitsu.com>,
	linux-mtd@lists.infradead.org
Subject: [PATCH 13/25] ubifs: introduce a field named as budgeted to ubifs_inode
Date: Tue, 21 Jul 2015 16:37:44 +0800	[thread overview]
Message-ID: <1437467876-22106-14-git-send-email-yangds.fnst@cn.fujitsu.com> (raw)
In-Reply-To: <1437467876-22106-1-git-send-email-yangds.fnst@cn.fujitsu.com>

There is a long-term pain in ubifs, we have to introduce a
ui_mutex in ubifs_inode to solve two problems below:

1: make some process atomic, such as ubifs_rename.
2: make sure we budget space for inode before dirting it.

About 1, it's true and we have to do it.

About 2, we can do it better.
	There is a ubifs_assert(mutex_is_locked(&ui->mutex)) in
ubifs_dirty_inode(). But there is probably some processes
are very long, and we can not make all of it into a pair of
lock/unlock ui->mutex.

E.g: dquot_disable().
	It would mark the quota files as dirty and write the
inode back. We can do a budget before this function, but we
can not make the whole dquot_disable() into mutex_lock/mutex_unlock.
Because we need to lock the ui_mutex in dquot_disable().

So, this commit introduce a ui->budgeted to allow us to make
budgeting and dirting in two different lock windows.

Result:
	ubifs_budget_space()
	mutex_lock();
	ui->budgeted = 1;
	mutex_unlock();
	...
	dquot_disable();

Signed-off-by: Dongsheng Yang <yangds.fnst@cn.fujitsu.com>
---
 fs/ubifs/file.c  |  7 +++++++
 fs/ubifs/ioctl.c |  1 +
 fs/ubifs/super.c | 14 +++++++++++++-
 fs/ubifs/ubifs.h |  1 +
 4 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/fs/ubifs/file.c b/fs/ubifs/file.c
index dc8bf0b..113c3a6 100644
--- a/fs/ubifs/file.c
+++ b/fs/ubifs/file.c
@@ -307,6 +307,7 @@ static int write_begin_slow(struct address_space *mapping,
 			 * budget we allocated.
 			 */
 			ubifs_release_dirty_inode_budget(c, ui);
+		ui->budgeted = 1;
 	}
 
 	*pagep = page;
@@ -357,6 +358,7 @@ static int allocate_budget(struct ubifs_info *c, struct page *page,
 		 * we need to budget the inode change.
 		 */
 		req.dirtied_ino = 1;
+		ui->budgeted = 1;
 	} else {
 		if (PageChecked(page))
 			/*
@@ -384,6 +386,7 @@ static int allocate_budget(struct ubifs_info *c, struct page *page,
 				 * needs a budget.
 				 */
 				req.dirtied_ino = 1;
+			ui->budgeted = 1;
 		}
 	}
 
@@ -1237,6 +1240,7 @@ static int do_setattr(struct ubifs_info *c, struct inode *inode,
 	do_attr_changes(inode, attr);
 
 	release = ui->dirty;
+	ui->budgeted = 1;
 	if (attr->ia_valid & ATTR_SIZE)
 		/*
 		 * Inode length changed, so we have to make sure
@@ -1397,6 +1401,7 @@ static int ubifs_update_time(struct inode *inode, struct timespec *time,
 		iflags |= I_DIRTY_SYNC;
 
 	release = ui->dirty;
+	ui->budgeted = 1;
 	__mark_inode_dirty(inode, iflags);
 	mutex_unlock(&ui->ui_mutex);
 	if (release)
@@ -1430,6 +1435,7 @@ static int update_mctime(struct inode *inode)
 		mutex_lock(&ui->ui_mutex);
 		inode->i_mtime = inode->i_ctime = ubifs_current_time(inode);
 		release = ui->dirty;
+		ui->budgeted = 1;
 		mark_inode_dirty_sync(inode);
 		mutex_unlock(&ui->ui_mutex);
 		if (release)
@@ -1556,6 +1562,7 @@ static int ubifs_vm_page_mkwrite(struct vm_area_struct *vma,
 		mutex_lock(&ui->ui_mutex);
 		inode->i_mtime = inode->i_ctime = ubifs_current_time(inode);
 		release = ui->dirty;
+		ui->budgeted = 1;
 		mark_inode_dirty_sync(inode);
 		mutex_unlock(&ui->ui_mutex);
 		if (release)
diff --git a/fs/ubifs/ioctl.c b/fs/ubifs/ioctl.c
index 3c7b29d..f015b81 100644
--- a/fs/ubifs/ioctl.c
+++ b/fs/ubifs/ioctl.c
@@ -128,6 +128,7 @@ static int setflags(struct inode *inode, int flags)
 	ubifs_set_inode_flags(inode);
 	inode->i_ctime = ubifs_current_time(inode);
 	release = ui->dirty;
+	ui->budgeted = 1;
 	mark_inode_dirty_sync(inode);
 	mutex_unlock(&ui->ui_mutex);
 
diff --git a/fs/ubifs/super.c b/fs/ubifs/super.c
index 2491fff..5fa21d6 100644
--- a/fs/ubifs/super.c
+++ b/fs/ubifs/super.c
@@ -331,6 +331,7 @@ static int ubifs_write_inode(struct inode *inode, struct writeback_control *wbc)
 	}
 
 	ui->dirty = 0;
+	ui->budgeted = 0;
 	mutex_unlock(&ui->ui_mutex);
 	ubifs_release_dirty_inode_budget(c, ui);
 	return err;
@@ -386,12 +387,23 @@ done:
 static void ubifs_dirty_inode(struct inode *inode, int flags)
 {
         struct ubifs_inode *ui = ubifs_inode(inode);
+	int need_unlock = 0;
 
-	ubifs_assert(mutex_is_locked(&ui->ui_mutex));
+	if (unlikely(!mutex_is_locked(&ui->ui_mutex))) {
+		/* We need to lock ui_mutex to access ui->budgeted */
+		mutex_lock(&ui->ui_mutex);
+		need_unlock = 1;
+	}
+
+	/* Check the budget for this inode */
+	ubifs_assert(ui->budgeted);
 	if (!ui->dirty) {
 		ui->dirty = 1;
 		dbg_gen("inode %lu",  inode->i_ino);
 	}
+
+	if (need_unlock)
+		mutex_unlock(&ui->ui_mutex);
 }
 
 static int ubifs_statfs(struct dentry *dentry, struct kstatfs *buf)
diff --git a/fs/ubifs/ubifs.h b/fs/ubifs/ubifs.h
index 9754bb6..28392a6 100644
--- a/fs/ubifs/ubifs.h
+++ b/fs/ubifs/ubifs.h
@@ -410,6 +410,7 @@ struct ubifs_inode {
 	unsigned int xattr_cnt;
 	unsigned int xattr_names;
 	unsigned int dirty:1;
+	unsigned int budgeted:1;
 	unsigned int xattr:1;
 	unsigned int bulk_read:1;
 	unsigned int compr_type:2;
-- 
1.8.4.2


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