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, 13 insertions, 2 deletions

diff --git a/fs/dcache.c b/fs/dcache.c
index 6f59f375ed9d..61beb40dd6bf 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -2171,7 +2171,7 @@ char *dynamic_dname(struct dentry *dentry, char *buffer, int buflen,
 /*
  * Write full pathname from the root of the filesystem into the buffer.
  */
-char *__dentry_path(struct dentry *dentry, char *buf, int buflen)
+static char *__dentry_path(struct dentry *dentry, char *buf, int buflen)
 {
         char *end = buf + buflen;
         char *retval;
@@ -2198,7 +2198,18 @@ char *__dentry_path(struct dentry *dentry, char *buf, int buflen)
 Elong:
         return ERR_PTR(-ENAMETOOLONG);
 }
-EXPORT_SYMBOL(__dentry_path);
+
+char *dentry_path_raw(struct dentry *dentry, char *buf, int buflen)
+{
+        char *retval;
+
+        spin_lock(&dcache_lock);
+        retval = __dentry_path(dentry, buf, buflen);
+        spin_unlock(&dcache_lock);
+
+        return retval;
+}
+EXPORT_SYMBOL(dentry_path_raw);
 
 char *dentry_path(struct dentry *dentry, char *buf, int buflen)
 {