fuse: add fuse_lookup_name() helper

Add a new helper function which sends a LOOKUP request with the supplied
name.  This will be used by the next patch to send special LOOKUP requests
with "." and ".." as the name.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index be5450d..51d0035 100644 (file)
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -112,18 +112,16 @@ static void fuse_invalidate_entry(struct dentry *entry)
        fuse_invalidate_entry_cache(entry);
 }
 
-static void fuse_lookup_init(struct fuse_req *req, struct inode *dir,
-                            struct dentry *entry,
+static void fuse_lookup_init(struct fuse_conn *fc, struct fuse_req *req,
+                            u64 nodeid, struct qstr *name,
                             struct fuse_entry_out *outarg)
 {
-       struct fuse_conn *fc = get_fuse_conn(dir);
-
        memset(outarg, 0, sizeof(struct fuse_entry_out));
        req->in.h.opcode = FUSE_LOOKUP;
-       req->in.h.nodeid = get_node_id(dir);
+       req->in.h.nodeid = nodeid;
        req->in.numargs = 1;
-       req->in.args[0].size = entry->d_name.len + 1;
-       req->in.args[0].value = entry->d_name.name;
+       req->in.args[0].size = name->len + 1;
+       req->in.args[0].value = name->name;
        req->out.numargs = 1;
        if (fc->minor < 9)
                req->out.args[0].size = FUSE_COMPAT_ENTRY_OUT_SIZE;
@@ -189,7 +187,8 @@ static int fuse_dentry_revalidate(struct dentry *entry, struct nameidata *nd)
                attr_version = fuse_get_attr_version(fc);
 
                parent = dget_parent(entry);
-               fuse_lookup_init(req, parent->d_inode, entry, &outarg);
+               fuse_lookup_init(fc, req, get_node_id(parent->d_inode),
+                                &entry->d_name, &outarg);
                request_send(fc, req);
                dput(parent);
                err = req->out.h.error;
@@ -255,73 +254,111 @@ static struct dentry *fuse_d_add_directory(struct dentry *entry,
        return d_splice_alias(inode, entry);
 }
 
-static struct dentry *fuse_lookup(struct inode *dir, struct dentry *entry,
-                                 struct nameidata *nd)
+int fuse_lookup_name(struct super_block *sb, u64 nodeid, struct qstr *name,
+                    struct fuse_entry_out *outarg, struct inode **inode)
 {
-       int err;
-       struct fuse_entry_out outarg;
-       struct inode *inode = NULL;
-       struct dentry *newent;
-       struct fuse_conn *fc = get_fuse_conn(dir);
+       struct fuse_conn *fc = get_fuse_conn_super(sb);
        struct fuse_req *req;
        struct fuse_req *forget_req;
        u64 attr_version;
+       int err;
 
-       if (entry->d_name.len > FUSE_NAME_MAX)
-               return ERR_PTR(-ENAMETOOLONG);
+       *inode = NULL;
+       err = -ENAMETOOLONG;
+       if (name->len > FUSE_NAME_MAX)
+               goto out;
 
        req = fuse_get_req(fc);
+       err = PTR_ERR(req);
        if (IS_ERR(req))
-               return ERR_CAST(req);
+               goto out;
 
        forget_req = fuse_get_req(fc);
+       err = PTR_ERR(forget_req);
        if (IS_ERR(forget_req)) {
                fuse_put_request(fc, req);
-               return ERR_CAST(forget_req);
+               goto out;
        }
 
        attr_version = fuse_get_attr_version(fc);
 
-       fuse_lookup_init(req, dir, entry, &outarg);
+       fuse_lookup_init(fc, req, nodeid, name, outarg);
        request_send(fc, req);
        err = req->out.h.error;
        fuse_put_request(fc, req);
        /* Zero nodeid is same as -ENOENT, but with valid timeout */
-       if (!err && outarg.nodeid &&
-           (invalid_nodeid(outarg.nodeid) ||
-            !fuse_valid_type(outarg.attr.mode)))
-               err = -EIO;
-       if (!err && outarg.nodeid) {
-               inode = fuse_iget(dir->i_sb, outarg.nodeid, outarg.generation,
-                                 &outarg.attr, entry_attr_timeout(&outarg),
-                                 attr_version);
-               if (!inode) {
-                       fuse_send_forget(fc, forget_req, outarg.nodeid, 1);
-                       return ERR_PTR(-ENOMEM);
-               }
+       if (err || !outarg->nodeid)
+               goto out_put_forget;
+
+       err = -EIO;
+       if (!outarg->nodeid)
+               goto out_put_forget;
+       if (!fuse_valid_type(outarg->attr.mode))
+               goto out_put_forget;
+
+       *inode = fuse_iget(sb, outarg->nodeid, outarg->generation,
+                          &outarg->attr, entry_attr_timeout(outarg),
+                          attr_version);
+       err = -ENOMEM;
+       if (!*inode) {
+               fuse_send_forget(fc, forget_req, outarg->nodeid, 1);
+               goto out;
        }
+       err = 0;
+
+ out_put_forget:
        fuse_put_request(fc, forget_req);
-       if (err && err != -ENOENT)
-               return ERR_PTR(err);
+ out:
+       return err;
+}
+
+static struct dentry *fuse_lookup(struct inode *dir, struct dentry *entry,
+                                 struct nameidata *nd)
+{
+       int err;
+       struct fuse_entry_out outarg;
+       struct inode *inode;
+       struct dentry *newent;
+       struct fuse_conn *fc = get_fuse_conn(dir);
+       bool outarg_valid = true;
+
+       err = fuse_lookup_name(dir->i_sb, get_node_id(dir), &entry->d_name,
+                              &outarg, &inode);
+       if (err == -ENOENT) {
+               outarg_valid = false;
+               err = 0;
+       }
+       if (err)
+               goto out_err;
+
+       err = -EIO;
+       if (inode && get_node_id(inode) == FUSE_ROOT_ID)
+               goto out_iput;
 
        if (inode && S_ISDIR(inode->i_mode)) {
                mutex_lock(&fc->inst_mutex);
                newent = fuse_d_add_directory(entry, inode);
                mutex_unlock(&fc->inst_mutex);
-               if (IS_ERR(newent)) {
-                       iput(inode);
-                       return newent;
-               }
-       } else
+               err = PTR_ERR(newent);
+               if (IS_ERR(newent))
+                       goto out_iput;
+       } else {
                newent = d_splice_alias(inode, entry);
+       }
 
        entry = newent ? newent : entry;
        entry->d_op = &fuse_dentry_operations;
-       if (!err)
+       if (outarg_valid)
                fuse_change_entry_timeout(entry, &outarg);
        else
                fuse_invalidate_entry_cache(entry);
+
        return newent;
+
+ out_iput:
+       iput(inode);
+ out_err:
+       return ERR_PTR(err);
 }
 
 /*