VFS: Provide empty name qstr

Provide an empty name (ie. "") qstr for general use.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

6 files changed, 15 insertions, 10 deletions

diff --git a/fs/dcache.c b/fs/dcache.c
index a9f995f6859e..95efb7b2bf84 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -90,6 +90,11 @@ EXPORT_SYMBOL(rename_lock);
 
 static struct kmem_cache *dentry_cache __read_mostly;
 
+const struct qstr empty_name = QSTR_INIT("", 0);
+EXPORT_SYMBOL(empty_name);
+const struct qstr slash_name = QSTR_INIT("/", 1);
+EXPORT_SYMBOL(slash_name);
+
 /*
  * This is the single most critical data structure when it comes
  * to the dcache: the hashtable for lookups. Somebody should try
@@ -1578,8 +1583,7 @@ struct dentry *__d_alloc(struct super_block *sb, const struct qstr *name)
          */
         dentry->d_iname[DNAME_INLINE_LEN-1] = 0;
         if (unlikely(!name)) {
-                static const struct qstr anon = QSTR_INIT("/", 1);
-                name = &anon;
+                name = &slash_name;
                 dname = dentry->d_iname;
         } else if (name->len > DNAME_INLINE_LEN-1) {
                 size_t size = offsetof(struct external_name, name[1]);
diff --git a/fs/gfs2/dir.c b/fs/gfs2/dir.c
index 79113219be5f..a5dfff6a033e 100644
--- a/fs/gfs2/dir.c
+++ b/fs/gfs2/dir.c
@@ -872,7 +872,6 @@ static struct gfs2_leaf *new_leaf(struct inode *inode, struct buffer_head **pbh,
         struct buffer_head *bh;
         struct gfs2_leaf *leaf;
         struct gfs2_dirent *dent;
-        struct qstr name = { .name = "" };
         struct timespec tv = current_time(inode);
 
         error = gfs2_alloc_blocks(ip, &bn, &n, 0, NULL);
@@ -896,7 +895,7 @@ static struct gfs2_leaf *new_leaf(struct inode *inode, struct buffer_head **pbh,
         leaf->lf_sec = cpu_to_be64(tv.tv_sec);
         memset(leaf->lf_reserved2, 0, sizeof(leaf->lf_reserved2));
         dent = (struct gfs2_dirent *)(leaf+1);
-        gfs2_qstr2dirent(&name, bh->b_size - sizeof(struct gfs2_leaf), dent);
+        gfs2_qstr2dirent(&empty_name, bh->b_size - sizeof(struct gfs2_leaf), dent);
         *pbh = bh;
         return leaf;
 }
diff --git a/fs/namei.c b/fs/namei.c
index 6571a5f5112e..0d35760fee00 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -3400,7 +3400,6 @@ out:
 
 struct dentry *vfs_tmpfile(struct dentry *dentry, umode_t mode, int open_flag)
 {
-        static const struct qstr name = QSTR_INIT("/", 1);
         struct dentry *child = NULL;
         struct inode *dir = dentry->d_inode;
         struct inode *inode;
@@ -3414,7 +3413,7 @@ struct dentry *vfs_tmpfile(struct dentry *dentry, umode_t mode, int open_flag)
         if (!dir->i_op->tmpfile)
                 goto out_err;
         error = -ENOMEM;
-        child = d_alloc(dentry, &name);
+        child = d_alloc(dentry, &slash_name);
         if (unlikely(!child))
                 goto out_err;
         error = dir->i_op->tmpfile(dir, child, mode);
diff --git a/fs/nsfs.c b/fs/nsfs.c
index f3db56e83dd2..08127a2b8559 100644
--- a/fs/nsfs.c
+++ b/fs/nsfs.c
@@ -53,7 +53,6 @@ static void nsfs_evict(struct inode *inode)
 static void *__ns_get_path(struct path *path, struct ns_common *ns)
 {
         struct vfsmount *mnt = nsfs_mnt;
-        struct qstr qname = { .name = "", };
         struct dentry *dentry;
         struct inode *inode;
         unsigned long d;
@@ -85,7 +84,7 @@ slow:
         inode->i_fop = &ns_file_operations;
         inode->i_private = ns;
 
-        dentry = d_alloc_pseudo(mnt->mnt_sb, &qname);
+        dentry = d_alloc_pseudo(mnt->mnt_sb, &empty_name);
         if (!dentry) {
                 iput(inode);
                 return ERR_PTR(-ENOMEM);
diff --git a/fs/pipe.c b/fs/pipe.c
index 73b84baf58f8..97e5be897753 100644
--- a/fs/pipe.c
+++ b/fs/pipe.c
@@ -739,13 +739,12 @@ int create_pipe_files(struct file **res, int flags)
         struct inode *inode = get_pipe_inode();
         struct file *f;
         struct path path;
-        static struct qstr name = { .name = "" };
 
         if (!inode)
                 return -ENFILE;
 
         err = -ENOMEM;
-        path.dentry = d_alloc_pseudo(pipe_mnt->mnt_sb, &name);
+        path.dentry = d_alloc_pseudo(pipe_mnt->mnt_sb, &empty_name);
         if (!path.dentry)
                 goto err_inode;
         path.mnt = mntget(pipe_mnt);
diff --git a/include/linux/dcache.h b/include/linux/dcache.h
index d2e38dc6172c..3f65a4fa72ed 100644
--- a/include/linux/dcache.h
+++ b/include/linux/dcache.h
@@ -55,6 +55,11 @@ struct qstr {
 
 #define QSTR_INIT(n,l) { { { .len = l } }, .name = n }
 
+extern const char empty_string[];
+extern const struct qstr empty_name;
+extern const char slash_string[];
+extern const struct qstr slash_name;
+
 struct dentry_stat_t {
         long nr_dentry;
         long nr_unused;