[PATCH 05/12] vfs: factor out lookup_mountpoint from new_mountpoint

From: Eric W. Biederman
Date: Tue Feb 25 2014 - 04:38:07 EST



I am shortly going to add a new user of struct mountpoint that
needs to look up existing entries but does not want to create
a struct mountpoint if one does not exist. Therefore to keep
the code simple and easy to read split out lookup_mountpoint
from new_mountpoint.

Signed-off-by: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
---
fs/namespace.c | 15 ++++++++++++---
1 files changed, 12 insertions(+), 3 deletions(-)

diff --git a/fs/namespace.c b/fs/namespace.c
index 32d380eabdac..f2f03082fe70 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -667,11 +667,10 @@ out:
return is_covered;
}

-static struct mountpoint *new_mountpoint(struct dentry *dentry)
+static struct mountpoint *lookup_mountpoint(struct dentry *dentry)
{
struct list_head *chain = mountpoint_hashtable + hash(NULL, dentry);
struct mountpoint *mp;
- int ret;

list_for_each_entry(mp, chain, m_hash) {
if (mp->m_dentry == dentry) {
@@ -682,6 +681,14 @@ static struct mountpoint *new_mountpoint(struct dentry *dentry)
return mp;
}
}
+ return NULL;
+}
+
+static struct mountpoint *new_mountpoint(struct dentry *dentry)
+{
+ struct list_head *chain = mountpoint_hashtable + hash(NULL, dentry);
+ struct mountpoint *mp;
+ int ret;

mp = kmalloc(sizeof(struct mountpoint), GFP_KERNEL);
if (!mp)
@@ -1702,7 +1709,9 @@ retry:
namespace_lock();
mnt = lookup_mnt(path);
if (likely(!mnt)) {
- struct mountpoint *mp = new_mountpoint(dentry);
+ struct mountpoint *mp = lookup_mountpoint(dentry);
+ if (!mp)
+ mp = new_mountpoint(dentry);
if (IS_ERR(mp)) {
namespace_unlock();
mutex_unlock(&dentry->d_inode->i_mutex);
--
1.7.5.4

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