9p: Track the root fid with its own variable during lookups

Improve readability by using a new variable when dealing with the root
fid. The root fid requires special handling in comparison to other fids
used during fid lookup.

Link: https://lkml.kernel.org/r/20220527000003.355812-3-tyhicks@linux.microsoft.com
Signed-off-by: Tyler Hicks <tyhicks@linux.microsoft.com>
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>

diff --git a/fs/9p/fid.c b/fs/9p/fid.c
index baf2b152229e3787191fa20d2ec0ad57c2ca2b0a..056b2a7e19641113ab0d9986eaffe4419c17d0ba 100644 (file)
--- a/fs/9p/fid.c
+++ b/fs/9p/fid.c
@@ -152,7 +152,7 @@ static struct p9_fid *v9fs_fid_lookup_with_uid(struct dentry *dentry,
        const unsigned char **wnames, *uname;
        int i, n, l, clone, access;
        struct v9fs_session_info *v9ses;
-       struct p9_fid *fid, *old_fid;
+       struct p9_fid *fid, *root_fid, *old_fid;
 
        v9ses = v9fs_dentry2v9ses(dentry);
        access = v9ses->flags & V9FS_ACCESS_MASK;
@@ -178,8 +178,8 @@ static struct p9_fid *v9fs_fid_lookup_with_uid(struct dentry *dentry,
        up_read(&v9ses->rename_sem);
 
        /* start from the root and try to do a lookup */
-       fid = v9fs_fid_find(dentry->d_sb->s_root, uid, any);
-       if (!fid) {
+       root_fid = v9fs_fid_find(dentry->d_sb->s_root, uid, any);
+       if (!root_fid) {
                /* the user is not attached to the fs yet */
                if (access == V9FS_ACCESS_SINGLE)
                        return ERR_PTR(-EPERM);
@@ -189,17 +189,18 @@ static struct p9_fid *v9fs_fid_lookup_with_uid(struct dentry *dentry,
                else
                        uname = v9ses->uname;
 
-               fid = p9_client_attach(v9ses->clnt, NULL, uname, uid,
-                                      v9ses->aname);
-               if (IS_ERR(fid))
-                       return fid;
+               root_fid = p9_client_attach(v9ses->clnt, NULL, uname, uid,
+                                           v9ses->aname);
+               if (IS_ERR(root_fid))
+                       return root_fid;
 
-               refcount_inc(&fid->count);
-               v9fs_fid_add(dentry->d_sb->s_root, fid);
+               refcount_inc(&root_fid->count);
+               v9fs_fid_add(dentry->d_sb->s_root, root_fid);
        }
        /* If we are root ourself just return that */
        if (dentry->d_sb->s_root == dentry)
-               return fid;
+               return root_fid;
+
        /*
         * Do a multipath walk with attached root.
         * When walking parent we need to make sure we
@@ -211,7 +212,8 @@ static struct p9_fid *v9fs_fid_lookup_with_uid(struct dentry *dentry,
                fid = ERR_PTR(n);
                goto err_out;
        }
-       old_fid = fid;
+       fid = root_fid;
+       old_fid = root_fid;
        clone = 1;
        i = 0;
        while (i < n) {
@@ -220,7 +222,7 @@ static struct p9_fid *v9fs_fid_lookup_with_uid(struct dentry *dentry,
                 * We need to hold rename lock when doing a multipath
                 * walk to ensure none of the patch component change
                 */
-               fid = p9_client_walk(fid, l, &wnames[i], clone);
+               fid = p9_client_walk(old_fid, l, &wnames[i], clone);
                /* non-cloning walk will return the same fid */
                if (fid != old_fid) {
                        p9_client_clunk(old_fid);