1 files changed, 80 insertions, 34 deletions

diff --git a/fs/9p/fid.c b/fs/9p/fid.c
index b00223c99d70..cd63e002d826 100644
--- a/fs/9p/fid.c
+++ b/fs/9p/fid.c
@@ -125,46 +125,17 @@ err_out:
         return -ENOMEM;
 }
 
-/**
- * v9fs_fid_lookup - lookup for a fid, try to walk if not found
- * @dentry: dentry to look for fid in
- *
- * Look for a fid in the specified dentry for the current user.
- * If no fid is found, try to create one walking from a fid from the parent
- * dentry (if it has one), or the root dentry. If the user haven't accessed
- * the fs yet, attach now and walk from the root.
- */
-
-struct p9_fid *v9fs_fid_lookup(struct dentry *dentry)
+static struct p9_fid *v9fs_fid_lookup_with_uid(struct dentry *dentry,
+                                               uid_t uid, int any)
 {
-        int i, n, l, clone, any, access;
-        u32 uid;
-        struct p9_fid *fid, *old_fid = NULL;
         struct dentry *ds;
-        struct v9fs_session_info *v9ses;
         char **wnames, *uname;
+        int i, n, l, clone, access;
+        struct v9fs_session_info *v9ses;
+        struct p9_fid *fid, *old_fid = NULL;
 
         v9ses = v9fs_inode2v9ses(dentry->d_inode);
         access = v9ses->flags & V9FS_ACCESS_MASK;
-        switch (access) {
-        case V9FS_ACCESS_SINGLE:
-        case V9FS_ACCESS_USER:
-        case V9FS_ACCESS_CLIENT:
-                uid = current_fsuid();
-                any = 0;
-                break;
-
-        case V9FS_ACCESS_ANY:
-                uid = v9ses->uid;
-                any = 1;
-                break;
-
-        default:
-                uid = ~0;
-                any = 0;
-                break;
-        }
-
         fid = v9fs_fid_find(dentry, uid, any);
         if (fid)
                 return fid;
@@ -250,6 +221,45 @@ err_out:
         return fid;
 }
 
+/**
+ * v9fs_fid_lookup - lookup for a fid, try to walk if not found
+ * @dentry: dentry to look for fid in
+ *
+ * Look for a fid in the specified dentry for the current user.
+ * If no fid is found, try to create one walking from a fid from the parent
+ * dentry (if it has one), or the root dentry. If the user haven't accessed
+ * the fs yet, attach now and walk from the root.
+ */
+
+struct p9_fid *v9fs_fid_lookup(struct dentry *dentry)
+{
+        uid_t uid;
+        int  any, access;
+        struct v9fs_session_info *v9ses;
+
+        v9ses = v9fs_inode2v9ses(dentry->d_inode);
+        access = v9ses->flags & V9FS_ACCESS_MASK;
+        switch (access) {
+        case V9FS_ACCESS_SINGLE:
+        case V9FS_ACCESS_USER:
+        case V9FS_ACCESS_CLIENT:
+                uid = current_fsuid();
+                any = 0;
+                break;
+
+        case V9FS_ACCESS_ANY:
+                uid = v9ses->uid;
+                any = 1;
+                break;
+
+        default:
+                uid = ~0;
+                any = 0;
+                break;
+        }
+        return v9fs_fid_lookup_with_uid(dentry, uid, any);
+}
+
 struct p9_fid *v9fs_fid_clone(struct dentry *dentry)
 {
         struct p9_fid *fid, *ret;
@@ -261,3 +271,39 @@ struct p9_fid *v9fs_fid_clone(struct dentry *dentry)
         ret = p9_client_walk(fid, 0, NULL, 1);
         return ret;
 }
+
+static struct p9_fid *v9fs_fid_clone_with_uid(struct dentry *dentry, uid_t uid)
+{
+        struct p9_fid *fid, *ret;
+
+        fid = v9fs_fid_lookup_with_uid(dentry, uid, 0);
+        if (IS_ERR(fid))
+                return fid;
+
+        ret = p9_client_walk(fid, 0, NULL, 1);
+        return ret;
+}
+
+struct p9_fid *v9fs_writeback_fid(struct dentry *dentry)
+{
+        int err;
+        struct p9_fid *fid;
+
+        fid = v9fs_fid_clone_with_uid(dentry, 0);
+        if (IS_ERR(fid))
+                goto error_out;
+        /*
+         * writeback fid will only be used to write back the
+         * dirty pages. We always request for the open fid in read-write
+         * mode so that a partial page write which result in page
+         * read can work.
+         */
+        err = p9_client_open(fid, O_RDWR);
+        if (err < 0) {
+                p9_client_clunk(fid);
+                fid = ERR_PTR(err);
+                goto error_out;
+        }
+error_out:
+        return fid;
+}