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Message-Id: <1243551665-23596-22-git-send-email-ebiederm@xmission.com>
Date: Thu, 28 May 2009 16:01:03 -0700
From: "Eric W. Biederman" <ebiederm@...ssion.com>
To: Andrew Morton <akpm@...ux-foundation.org>,
Greg Kroah-Hartman <gregkh@...e.de>
Cc: <linux-kernel@...r.kernel.org>, Tejun Heo <tj@...nel.org>,
Cornelia Huck <cornelia.huck@...ibm.com>,
<linux-fsdevel@...r.kernel.org>,
Kay Sievers <kay.sievers@...y.org>, Greg KH <greg@...ah.com>,
"Eric W. Biederman" <ebiederm@...ssion.com>,
"Eric W. Biederman" <ebiederm@...stanetworks.com>
Subject: [PATCH 22/24] sysfs: Make sysfs_rename_link atomic
From: Eric W. Biederman <ebiederm@...ssion.com>
Use the existing sysfs_rename to make sysfs_rename_link an atomic
operation that does less work. While I am at add additional sanity
checking to ensure it is a symlink I am renaming.
Acked-by: Kay Sievers <kay.sievers@...y.org>
Signed-off-by: Eric W. Biederman <ebiederm@...stanetworks.com>
---
fs/sysfs/symlink.c | 26 ++++++++++++++++++++++++--
1 files changed, 24 insertions(+), 2 deletions(-)
diff --git a/fs/sysfs/symlink.c b/fs/sysfs/symlink.c
index fc5fc86..39d050b 100644
--- a/fs/sysfs/symlink.c
+++ b/fs/sysfs/symlink.c
@@ -106,8 +106,30 @@ void sysfs_remove_link(struct kobject * kobj, const char * name)
int sysfs_rename_link(struct kobject *kobj, struct kobject *targ,
const char *old, const char *new)
{
- sysfs_remove_link(kobj, old);
- return sysfs_create_link(kobj, targ, new);
+ struct sysfs_dirent *parent_sd, *sd = NULL;
+ int result;
+
+ if (!kobj)
+ parent_sd = &sysfs_root;
+ else
+ parent_sd = kobj->sd;
+
+ result = -ENOENT;
+ sd = sysfs_get_dirent(parent_sd, old);
+ if (!sd)
+ goto out;
+
+ result = -EINVAL;
+ if (sysfs_type(sd) != SYSFS_KOBJ_LINK)
+ goto out;
+ if (sd->s_symlink.target_sd->s_dir.kobj != targ)
+ goto out;
+
+ result = sysfs_rename(sd, parent_sd, new);
+
+out:
+ sysfs_put(sd);
+ return result;
}
static int sysfs_get_target_path(struct sysfs_dirent *parent_sd,
--
1.6.3.1.54.g99dd.dirty
--
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