linux-kernel - [PATCH 12/12] Unionfs: lock parent dentry branch config in write

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Message-Id: <12091619542355-git-send-email-ezk@cs.sunysb.edu>
Date:	Fri, 25 Apr 2008 18:19:08 -0400
From:	Erez Zadok <ezk@...sunysb.edu>
To:	akpm@...ux-foundation.org
Cc:	linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org,
	viro@....linux.org.uk, hch@...radead.org,
	Erez Zadok <ezk@...sunysb.edu>
Subject: [PATCH 12/12] Unionfs: lock parent dentry branch config in write

Ensure that branch configuration is available to file_revalidate should a
copyup be required.

Signed-off-by: Erez Zadok <ezk@...sunysb.edu>
---
 fs/unionfs/file.c |    6 +++++-
 1 files changed, 5 insertions(+), 1 deletions(-)

diff --git a/fs/unionfs/file.c b/fs/unionfs/file.c
index 09f594d..9b5fc58 100644
--- a/fs/unionfs/file.c
+++ b/fs/unionfs/file.c
@@ -55,7 +55,9 @@ static ssize_t unionfs_write(struct file *file, const char __user *buf,
 
 	unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_PARENT);
 	unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
-	err = unionfs_file_revalidate(file, true);
+	if (dentry != dentry->d_parent)
+		unionfs_lock_dentry(dentry->d_parent, UNIONFS_DMUTEX_PARENT);
+	err = unionfs_file_revalidate_locked(file, true);
 	if (unlikely(err))
 		goto out;
 
@@ -72,6 +74,8 @@ static ssize_t unionfs_write(struct file *file, const char __user *buf,
 	}
 
 out:
+	if (dentry != dentry->d_parent)
+		unionfs_unlock_dentry(dentry->d_parent);
 	unionfs_unlock_dentry(dentry);
 	unionfs_read_unlock(dentry->d_sb);
 	return err;
-- 
1.5.2.2

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