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>

1 files changed, 77 insertions, 40 deletions

diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index be5450dd6387..51d0035ff07e 100644
--- 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);
 }
 
 /*