linux-kernel - [PATCH 17/30] Unionfs: remove unnecessary locking in follow-link

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Message-Id: <1198874593425-git-send-email-ezk@cs.sunysb.edu>
Date:	Fri, 28 Dec 2007 15:42:51 -0500
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 17/30] Unionfs: remove unnecessary locking in follow-link

Signed-off-by: Erez Zadok <ezk@...sunysb.edu>
---
 fs/unionfs/inode.c |    6 ++----
 1 files changed, 2 insertions(+), 4 deletions(-)

diff --git a/fs/unionfs/inode.c b/fs/unionfs/inode.c
index 37258c8..7ec9c1b 100644
--- a/fs/unionfs/inode.c
+++ b/fs/unionfs/inode.c
@@ -851,7 +851,8 @@ out:
  * nor do we need to revalidate it either.  It is safe to not lock our
  * dentry here, nor revalidate it, because unionfs_follow_link does not do
  * anything (prior to calling ->readlink) which could become inconsistent
- * due to branch management.
+ * due to branch management.  We also don't need to lock our super because
+ * this function isn't affected by branch-management.
  */
 static void *unionfs_follow_link(struct dentry *dentry, struct nameidata *nd)
 {
@@ -859,8 +860,6 @@ static void *unionfs_follow_link(struct dentry *dentry, struct nameidata *nd)
 	int len = PAGE_SIZE, err;
 	mm_segment_t old_fs;
 
-	unionfs_read_lock(dentry->d_sb);
-
 	/* This is freed by the put_link method assuming a successful call. */
 	buf = kmalloc(len, GFP_KERNEL);
 	if (unlikely(!buf)) {
@@ -885,7 +884,6 @@ static void *unionfs_follow_link(struct dentry *dentry, struct nameidata *nd)
 out:
 	unionfs_check_dentry(dentry);
 	unionfs_check_nd(nd);
-	unionfs_read_unlock(dentry->d_sb);
 	return ERR_PTR(err);
 }
 
-- 
1.5.2.2

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