hostfs: simplify locking

Remove dcache_lock locking from hostfs filesystem, and move it into dcache
helpers. All that is required is a coherent path name. Protection from
concurrent modification of the namespace after path name generation is not
provided in current code, because dcache_lock is dropped before the path is
used.

Signed-off-by: Nick Piggin <npiggin@kernel.dk>

1 files changed, 10 insertions, 14 deletions

diff --git a/fs/hostfs/hostfs_kern.c b/fs/hostfs/hostfs_kern.c
index cfe8bc7de511..39dc505ed273 100644
--- a/fs/hostfs/hostfs_kern.c
+++ b/fs/hostfs/hostfs_kern.c
@@ -92,12 +92,10 @@ __uml_setup("hostfs=", hostfs_args,
 
 static char *__dentry_name(struct dentry *dentry, char *name)
 {
-        char *p = __dentry_path(dentry, name, PATH_MAX);
+        char *p = dentry_path_raw(dentry, name, PATH_MAX);
         char *root;
         size_t len;
 
-        spin_unlock(&dcache_lock);
-
         root = dentry->d_sb->s_fs_info;
         len = strlen(root);
         if (IS_ERR(p)) {
@@ -123,25 +121,23 @@ static char *dentry_name(struct dentry *dentry)
         if (!name)
                 return NULL;
 
-        spin_lock(&dcache_lock);
         return __dentry_name(dentry, name); /* will unlock */
 }
 
 static char *inode_name(struct inode *ino)
 {
         struct dentry *dentry;
-        char *name = __getname();
-        if (!name)
-                return NULL;
+        char *name;
 
-        spin_lock(&dcache_lock);
-        if (list_empty(&ino->i_dentry)) {
-                spin_unlock(&dcache_lock);
-                __putname(name);
+        dentry = d_find_alias(ino);
+        if (!dentry)
                 return NULL;
-        }
-        dentry = list_first_entry(&ino->i_dentry, struct dentry, d_alias);
-        return __dentry_name(dentry, name); /* will unlock */
+
+        name = dentry_name(dentry);
+
+        dput(dentry);
+
+        return name;
 }
 
 static char *follow_link(char *link)