linux-kernel - [PATCH 3/4] kill-the-bkl/reiserfs: fix recursive reiserfs write lock in reiserfs_commit

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Date:	Tue, 25 Aug 2009 04:32:49 +0200
From:	Frederic Weisbecker <fweisbec@...il.com>
To:	LKML <linux-kernel@...r.kernel.org>
Cc:	LKML <linux-kernel@...r.kernel.org>,
	Frederic Weisbecker <fweisbec@...il.com>,
	Chris Mason <chris.mason@...cle.com>,
	Roland Dreier <rdreier@...co.com>, Ingo Molnar <mingo@...e.hu>,
	Andi Kleen <andi@...stfloor.org>,
	Jeff Mahoney <jeffm@...e.com>,
	Alexander Beregalov <a.beregalov@...il.com>,
	Bron Gondwana <brong@...tmail.fm>,
	Reiserfs <reiserfs-devel@...r.kernel.org>,
	Al Viro <viro@...iv.linux.org.uk>,
	Andrea Gelmini <andrea.gelmini@...il.com>,
	"Trenton D. Adams" <trenton.d.adams@...il.com>,
	Thomas Meyer <thomas@...3r.de>,
	Alessio Igor Bogani <abogani@...ware.it>,
	Marcel Hilzinger <mhilzinger@...uxnewmedia.de>,
	Edward Shishkin <edward.shishkin@...il.com>,
	Laurent Riffard <laurent.riffard@...e.fr>
Subject: [PATCH 3/4] kill-the-bkl/reiserfs: fix recursive reiserfs write lock in reiserfs_commit_write()

reiserfs_commit_write() is always called with the write lock held.
Thus the current calls to reiserfs_write_lock() in this function are
acquiring the lock recursively.
We can safely drop them.

This also solves further assumptions for this lock to be really
released while calling reiserfs_write_unlock().

Signed-off-by: Frederic Weisbecker <fweisbec@...il.com>
Cc: Jeff Mahoney <jeffm@...e.com>
Cc: Chris Mason <chris.mason@...cle.com>
Cc: Ingo Molnar <mingo@...e.hu>
Cc: Alexander Beregalov <a.beregalov@...il.com>
Cc: Laurent Riffard <laurent.riffard@...e.fr>
---
 fs/reiserfs/inode.c |   11 ++---------
 1 files changed, 2 insertions(+), 9 deletions(-)

diff --git a/fs/reiserfs/inode.c b/fs/reiserfs/inode.c
index 853f4f6..965c8ea 100644
--- a/fs/reiserfs/inode.c
+++ b/fs/reiserfs/inode.c
@@ -2795,7 +2795,6 @@ int reiserfs_commit_write(struct file *f, struct page *page,
 	 */
 	if (pos > inode->i_size) {
 		struct reiserfs_transaction_handle myth;
-		reiserfs_write_lock(inode->i_sb);
 		/* If the file have grown beyond the border where it
 		   can have a tail, unmark it as needing a tail
 		   packing */
@@ -2806,10 +2805,9 @@ int reiserfs_commit_write(struct file *f, struct page *page,
 			REISERFS_I(inode)->i_flags &= ~i_pack_on_close_mask;
 
 		ret = journal_begin(&myth, inode->i_sb, 1);
-		if (ret) {
-			reiserfs_write_unlock(inode->i_sb);
+		if (ret)
 			goto journal_error;
-		}
+
 		reiserfs_update_inode_transaction(inode);
 		inode->i_size = pos;
 		/*
@@ -2821,16 +2819,13 @@ int reiserfs_commit_write(struct file *f, struct page *page,
 		reiserfs_update_sd(&myth, inode);
 		update_sd = 1;
 		ret = journal_end(&myth, inode->i_sb, 1);
-		reiserfs_write_unlock(inode->i_sb);
 		if (ret)
 			goto journal_error;
 	}
 	if (th) {
-		reiserfs_write_lock(inode->i_sb);
 		if (!update_sd)
 			mark_inode_dirty(inode);
 		ret = reiserfs_end_persistent_transaction(th);
-		reiserfs_write_unlock(inode->i_sb);
 		if (ret)
 			goto out;
 	}
@@ -2840,11 +2835,9 @@ int reiserfs_commit_write(struct file *f, struct page *page,
 
       journal_error:
 	if (th) {
-		reiserfs_write_lock(inode->i_sb);
 		if (!update_sd)
 			reiserfs_update_sd(th, inode);
 		ret = reiserfs_end_persistent_transaction(th);
-		reiserfs_write_unlock(inode->i_sb);
 	}
 
 	return ret;
-- 
1.6.2.3

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