9p fid refcount: cleanup p9_fid_put calls

Simplify p9_fid_put cleanup path in many 9p functions since the function
is noop on null or error fids.

Also make the *_add_fid() helpers "steal" the fid by nulling its
pointer, so put after them will be noop.

This should lead to no change of behaviour

Link: https://lkml.kernel.org/r/20220612085330.1451496-7-asmadeus@codewreck.org
Reviewed-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 d792499..289a85e 100644 (file)
--- a/fs/9p/fid.c
+++ b/fs/9p/fid.c
@@ -31,11 +31,15 @@ static inline void __add_fid(struct dentry *dentry, struct p9_fid *fid)
  * @fid: fid to add
  *
  */
-void v9fs_fid_add(struct dentry *dentry, struct p9_fid *fid)
+void v9fs_fid_add(struct dentry *dentry, struct p9_fid **pfid)
 {
+       struct p9_fid *fid = *pfid;
+
        spin_lock(&dentry->d_lock);
        __add_fid(dentry, fid);
        spin_unlock(&dentry->d_lock);
+
+       *pfid = NULL;
 }
 
 /**
@@ -72,11 +76,15 @@ static struct p9_fid *v9fs_fid_find_inode(struct inode *inode, kuid_t uid)
  *
  */
 
-void v9fs_open_fid_add(struct inode *inode, struct p9_fid *fid)
+void v9fs_open_fid_add(struct inode *inode, struct p9_fid **pfid)
 {
+       struct p9_fid *fid = *pfid;
+
        spin_lock(&inode->i_lock);
        hlist_add_head(&fid->ilist, (struct hlist_head *)&inode->i_private);
        spin_unlock(&inode->i_lock);
+
+       *pfid = NULL;
 }
 
 
@@ -189,13 +197,13 @@ static struct p9_fid *v9fs_fid_lookup_with_uid(struct dentry *dentry,
                else
                        uname = v9ses->uname;
 
-               root_fid = p9_client_attach(v9ses->clnt, NULL, uname, uid,
-                                           v9ses->aname);
-               if (IS_ERR(root_fid))
-                       return root_fid;
+               fid = p9_client_attach(v9ses->clnt, NULL, uname, uid,
+                                      v9ses->aname);
+               if (IS_ERR(fid))
+                       return fid;
 
-               p9_fid_get(root_fid);
-               v9fs_fid_add(dentry->d_sb->s_root, root_fid);
+               root_fid = p9_fid_get(fid);
+               v9fs_fid_add(dentry->d_sb->s_root, &fid);
        }
        /* If we are root ourself just return that */
        if (dentry->d_sb->s_root == dentry)

diff --git a/fs/9p/fid.h b/fs/9p/fid.h
index 3168dfa..8a4e8cd 100644 (file)
--- a/fs/9p/fid.h
+++ b/fs/9p/fid.h
@@ -13,9 +13,9 @@ static inline struct p9_fid *v9fs_parent_fid(struct dentry *dentry)
 {
        return v9fs_fid_lookup(dentry->d_parent);
 }
-void v9fs_fid_add(struct dentry *dentry, struct p9_fid *fid);
+void v9fs_fid_add(struct dentry *dentry, struct p9_fid **fid);
 struct p9_fid *v9fs_writeback_fid(struct dentry *dentry);
-void v9fs_open_fid_add(struct inode *inode, struct p9_fid *fid);
+void v9fs_open_fid_add(struct inode *inode, struct p9_fid **fid);
 static inline struct p9_fid *clone_fid(struct p9_fid *fid)
 {
        return IS_ERR(fid) ? fid :  p9_client_walk(fid, 0, NULL, 1);

diff --git a/fs/9p/vfs_file.c b/fs/9p/vfs_file.c
index 8276f3a..aec43ba 100644 (file)
--- a/fs/9p/vfs_file.c
+++ b/fs/9p/vfs_file.c
@@ -69,9 +69,10 @@ int v9fs_file_open(struct inode *inode, struct file *file)
                if ((file->f_flags & O_APPEND) &&
                        (!v9fs_proto_dotu(v9ses) && !v9fs_proto_dotl(v9ses)))
                        generic_file_llseek(file, 0, SEEK_END);
+
+               file->private_data = fid;
        }
 
-       file->private_data = fid;
        mutex_lock(&v9inode->v_mutex);
        if ((v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE) &&
            !v9inode->writeback_fid &&
@@ -95,7 +96,7 @@ int v9fs_file_open(struct inode *inode, struct file *file)
        if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
                fscache_use_cookie(v9fs_inode_cookie(v9inode),
                                   file->f_mode & FMODE_WRITE);
-       v9fs_open_fid_add(inode, fid);
+       v9fs_open_fid_add(inode, &fid);
        return 0;
 out_error:
        p9_fid_put(file->private_data);

diff --git a/fs/9p/vfs_inode.c b/fs/9p/vfs_inode.c
index bde1877..4d1a4a8 100644 (file)
--- a/fs/9p/vfs_inode.c
+++ b/fs/9p/vfs_inode.c
@@ -399,10 +399,8 @@ void v9fs_evict_inode(struct inode *inode)
 
        fscache_relinquish_cookie(v9fs_inode_cookie(v9inode), false);
        /* clunk the fid stashed in writeback_fid */
-       if (v9inode->writeback_fid) {
-               p9_fid_put(v9inode->writeback_fid);
-               v9inode->writeback_fid = NULL;
-       }
+       p9_fid_put(v9inode->writeback_fid);
+       v9inode->writeback_fid = NULL;
 }
 
 static int v9fs_test_inode(struct inode *inode, void *data)
@@ -633,14 +631,12 @@ v9fs_create(struct v9fs_session_info *v9ses, struct inode *dir,
        if (IS_ERR(ofid)) {
                err = PTR_ERR(ofid);
                p9_debug(P9_DEBUG_VFS, "p9_client_walk failed %d\n", err);
-               p9_fid_put(dfid);
-               return ERR_PTR(err);
+               goto error;
        }
 
        err = p9_client_fcreate(ofid, name, perm, mode, extension);
        if (err < 0) {
                p9_debug(P9_DEBUG_VFS, "p9_client_fcreate failed %d\n", err);
-               p9_fid_put(dfid);
                goto error;
        }
 
@@ -651,8 +647,6 @@ v9fs_create(struct v9fs_session_info *v9ses, struct inode *dir,
                        err = PTR_ERR(fid);
                        p9_debug(P9_DEBUG_VFS,
                                   "p9_client_walk failed %d\n", err);
-                       fid = NULL;
-                       p9_fid_put(dfid);
                        goto error;
                }
                /*
@@ -663,21 +657,17 @@ v9fs_create(struct v9fs_session_info *v9ses, struct inode *dir,
                        err = PTR_ERR(inode);
                        p9_debug(P9_DEBUG_VFS,
                                   "inode creation failed %d\n", err);
-                       p9_fid_put(dfid);
                        goto error;
                }
-               v9fs_fid_add(dentry, fid);
+               v9fs_fid_add(dentry, &fid);
                d_instantiate(dentry, inode);
        }
        p9_fid_put(dfid);
        return ofid;
 error:
-       if (ofid)
-               p9_fid_put(ofid);
-
-       if (fid)
-               p9_fid_put(fid);
-
+       p9_fid_put(dfid);
+       p9_fid_put(ofid);
+       p9_fid_put(fid);
        return ERR_PTR(err);
 }
 
@@ -804,9 +794,9 @@ struct dentry *v9fs_vfs_lookup(struct inode *dir, struct dentry *dentry,
        res = d_splice_alias(inode, dentry);
        if (!IS_ERR(fid)) {
                if (!res)
-                       v9fs_fid_add(dentry, fid);
+                       v9fs_fid_add(dentry, &fid);
                else if (!IS_ERR(res))
-                       v9fs_fid_add(res, fid);
+                       v9fs_fid_add(res, &fid);
                else
                        p9_fid_put(fid);
        }
@@ -847,7 +837,6 @@ v9fs_vfs_atomic_open(struct inode *dir, struct dentry *dentry,
                                                v9fs_proto_dotu(v9ses)));
        if (IS_ERR(fid)) {
                err = PTR_ERR(fid);
-               fid = NULL;
                goto error;
        }
 
@@ -882,7 +871,7 @@ v9fs_vfs_atomic_open(struct inode *dir, struct dentry *dentry,
        if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
                fscache_use_cookie(v9fs_inode_cookie(v9inode),
                                   file->f_mode & FMODE_WRITE);
-       v9fs_open_fid_add(inode, fid);
+       v9fs_open_fid_add(inode, &fid);
 
        file->f_mode |= FMODE_CREATED;
 out:
@@ -890,8 +879,7 @@ out:
        return err;
 
 error:
-       if (fid)
-               p9_fid_put(fid);
+       p9_fid_put(fid);
        goto out;
 }
 
@@ -939,9 +927,9 @@ v9fs_vfs_rename(struct user_namespace *mnt_userns, struct inode *old_dir,
        struct inode *old_inode;
        struct inode *new_inode;
        struct v9fs_session_info *v9ses;
-       struct p9_fid *oldfid, *dfid;
-       struct p9_fid *olddirfid;
-       struct p9_fid *newdirfid;
+       struct p9_fid *oldfid = NULL, *dfid = NULL;
+       struct p9_fid *olddirfid = NULL;
+       struct p9_fid *newdirfid = NULL;
        struct p9_wstat wstat;
 
        if (flags)
@@ -958,21 +946,22 @@ v9fs_vfs_rename(struct user_namespace *mnt_userns, struct inode *old_dir,
 
        dfid = v9fs_parent_fid(old_dentry);
        olddirfid = clone_fid(dfid);
-       if (dfid && !IS_ERR(dfid))
-               p9_fid_put(dfid);
+       p9_fid_put(dfid);
+       dfid = NULL;
 
        if (IS_ERR(olddirfid)) {
                retval = PTR_ERR(olddirfid);
-               goto done;
+               goto error;
        }
 
        dfid = v9fs_parent_fid(new_dentry);
        newdirfid = clone_fid(dfid);
        p9_fid_put(dfid);
+       dfid = NULL;
 
        if (IS_ERR(newdirfid)) {
                retval = PTR_ERR(newdirfid);
-               goto clunk_olddir;
+               goto error;
        }
 
        down_write(&v9ses->rename_sem);
@@ -983,7 +972,7 @@ v9fs_vfs_rename(struct user_namespace *mnt_userns, struct inode *old_dir,
                        retval = p9_client_rename(oldfid, newdirfid,
                                                  new_dentry->d_name.name);
                if (retval != -EOPNOTSUPP)
-                       goto clunk_newdir;
+                       goto error_locked;
        }
        if (old_dentry->d_parent != new_dentry->d_parent) {
                /*
@@ -992,14 +981,14 @@ v9fs_vfs_rename(struct user_namespace *mnt_userns, struct inode *old_dir,
 
                p9_debug(P9_DEBUG_ERROR, "old dir and new dir are different\n");
                retval = -EXDEV;
-               goto clunk_newdir;
+               goto error_locked;
        }
        v9fs_blank_wstat(&wstat);
        wstat.muid = v9ses->uname;
        wstat.name = new_dentry->d_name.name;
        retval = p9_client_wstat(oldfid, &wstat);
 
-clunk_newdir:
+error_locked:
        if (!retval) {
                if (new_inode) {
                        if (S_ISDIR(new_inode->i_mode))
@@ -1020,12 +1009,10 @@ clunk_newdir:
                d_move(old_dentry, new_dentry);
        }
        up_write(&v9ses->rename_sem);
-       p9_fid_put(newdirfid);
 
-clunk_olddir:
+error:
+       p9_fid_put(newdirfid);
        p9_fid_put(olddirfid);
-
-done:
        p9_fid_put(oldfid);
        return retval;
 }

diff --git a/fs/9p/vfs_inode_dotl.c b/fs/9p/vfs_inode_dotl.c
index 09b124f..5cfa4b4 100644 (file)
--- a/fs/9p/vfs_inode_dotl.c
+++ b/fs/9p/vfs_inode_dotl.c
@@ -238,7 +238,7 @@ v9fs_vfs_atomic_open_dotl(struct inode *dir, struct dentry *dentry,
        struct inode *inode;
        struct p9_fid *fid = NULL;
        struct v9fs_inode *v9inode;
-       struct p9_fid *dfid, *ofid, *inode_fid;
+       struct p9_fid *dfid = NULL, *ofid = NULL, *inode_fid = NULL;
        struct v9fs_session_info *v9ses;
        struct posix_acl *pacl = NULL, *dacl = NULL;
        struct dentry *res = NULL;
@@ -274,7 +274,6 @@ v9fs_vfs_atomic_open_dotl(struct inode *dir, struct dentry *dentry,
        if (IS_ERR(ofid)) {
                err = PTR_ERR(ofid);
                p9_debug(P9_DEBUG_VFS, "p9_client_walk failed %d\n", err);
-               p9_fid_put(dfid);
                goto out;
        }
 
@@ -286,38 +285,34 @@ v9fs_vfs_atomic_open_dotl(struct inode *dir, struct dentry *dentry,
        if (err) {
                p9_debug(P9_DEBUG_VFS, "Failed to get acl values in creat %d\n",
                         err);
-               p9_fid_put(dfid);
-               goto error;
+               goto out;
        }
        err = p9_client_create_dotl(ofid, name, v9fs_open_to_dotl_flags(flags),
                                    mode, gid, &qid);
        if (err < 0) {
                p9_debug(P9_DEBUG_VFS, "p9_client_open_dotl failed in creat %d\n",
                         err);
-               p9_fid_put(dfid);
-               goto error;
+               goto out;
        }
        v9fs_invalidate_inode_attr(dir);
 
        /* instantiate inode and assign the unopened fid to the dentry */
        fid = p9_client_walk(dfid, 1, &name, 1);
-       p9_fid_put(dfid);
        if (IS_ERR(fid)) {
                err = PTR_ERR(fid);
                p9_debug(P9_DEBUG_VFS, "p9_client_walk failed %d\n", err);
-               fid = NULL;
-               goto error;
+               goto out;
        }
        inode = v9fs_get_new_inode_from_fid(v9ses, fid, dir->i_sb);
        if (IS_ERR(inode)) {
                err = PTR_ERR(inode);
                p9_debug(P9_DEBUG_VFS, "inode creation failed %d\n", err);
-               goto error;
+               goto out;
        }
        /* Now set the ACL based on the default value */
        v9fs_set_create_acl(inode, fid, dacl, pacl);
 
-       v9fs_fid_add(dentry, fid);
+       v9fs_fid_add(dentry, &fid);
        d_instantiate(dentry, inode);
 
        v9inode = V9FS_I(inode);
@@ -336,7 +331,7 @@ v9fs_vfs_atomic_open_dotl(struct inode *dir, struct dentry *dentry,
                if (IS_ERR(inode_fid)) {
                        err = PTR_ERR(inode_fid);
                        mutex_unlock(&v9inode->v_mutex);
-                       goto err_clunk_old_fid;
+                       goto out;
                }
                v9inode->writeback_fid = (void *) inode_fid;
        }
@@ -344,25 +339,20 @@ v9fs_vfs_atomic_open_dotl(struct inode *dir, struct dentry *dentry,
        /* Since we are opening a file, assign the open fid to the file */
        err = finish_open(file, dentry, generic_file_open);
        if (err)
-               goto err_clunk_old_fid;
+               goto out;
        file->private_data = ofid;
        if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
                fscache_use_cookie(v9fs_inode_cookie(v9inode),
                                   file->f_mode & FMODE_WRITE);
-       v9fs_open_fid_add(inode, ofid);
+       v9fs_open_fid_add(inode, &ofid);
        file->f_mode |= FMODE_CREATED;
 out:
+       p9_fid_put(dfid);
+       p9_fid_put(ofid);
+       p9_fid_put(fid);
        v9fs_put_acl(dacl, pacl);
        dput(res);
        return err;
-
-error:
-       if (fid)
-               p9_fid_put(fid);
-err_clunk_old_fid:
-       if (ofid)
-               p9_fid_put(ofid);
-       goto out;
 }
 
 /**
@@ -400,7 +390,6 @@ static int v9fs_vfs_mkdir_dotl(struct user_namespace *mnt_userns,
        if (IS_ERR(dfid)) {
                err = PTR_ERR(dfid);
                p9_debug(P9_DEBUG_VFS, "fid lookup failed %d\n", err);
-               dfid = NULL;
                goto error;
        }
 
@@ -422,7 +411,6 @@ static int v9fs_vfs_mkdir_dotl(struct user_namespace *mnt_userns,
                err = PTR_ERR(fid);
                p9_debug(P9_DEBUG_VFS, "p9_client_walk failed %d\n",
                         err);
-               fid = NULL;
                goto error;
        }
 
@@ -435,10 +423,9 @@ static int v9fs_vfs_mkdir_dotl(struct user_namespace *mnt_userns,
                                 err);
                        goto error;
                }
-               v9fs_fid_add(dentry, fid);
+               v9fs_fid_add(dentry, &fid);
                v9fs_set_create_acl(inode, fid, dacl, pacl);
                d_instantiate(dentry, inode);
-               fid = NULL;
                err = 0;
        } else {
                /*
@@ -457,8 +444,7 @@ static int v9fs_vfs_mkdir_dotl(struct user_namespace *mnt_userns,
        inc_nlink(dir);
        v9fs_invalidate_inode_attr(dir);
 error:
-       if (fid)
-               p9_fid_put(fid);
+       p9_fid_put(fid);
        v9fs_put_acl(dacl, pacl);
        p9_fid_put(dfid);
        return err;
@@ -743,7 +729,6 @@ v9fs_vfs_symlink_dotl(struct user_namespace *mnt_userns, struct inode *dir,
                        err = PTR_ERR(fid);
                        p9_debug(P9_DEBUG_VFS, "p9_client_walk failed %d\n",
                                 err);
-                       fid = NULL;
                        goto error;
                }
 
@@ -755,9 +740,8 @@ v9fs_vfs_symlink_dotl(struct user_namespace *mnt_userns, struct inode *dir,
                                 err);
                        goto error;
                }
-               v9fs_fid_add(dentry, fid);
+               v9fs_fid_add(dentry, &fid);
                d_instantiate(dentry, inode);
-               fid = NULL;
                err = 0;
        } else {
                /* Not in cached mode. No need to populate inode with stat */
@@ -770,9 +754,7 @@ v9fs_vfs_symlink_dotl(struct user_namespace *mnt_userns, struct inode *dir,
        }
 
 error:
-       if (fid)
-               p9_fid_put(fid);
-
+       p9_fid_put(fid);
        p9_fid_put(dfid);
        return err;
 }
@@ -866,7 +848,6 @@ v9fs_vfs_mknod_dotl(struct user_namespace *mnt_userns, struct inode *dir,
        if (IS_ERR(dfid)) {
                err = PTR_ERR(dfid);
                p9_debug(P9_DEBUG_VFS, "fid lookup failed %d\n", err);
-               dfid = NULL;
                goto error;
        }
 
@@ -891,7 +872,6 @@ v9fs_vfs_mknod_dotl(struct user_namespace *mnt_userns, struct inode *dir,
                err = PTR_ERR(fid);
                p9_debug(P9_DEBUG_VFS, "p9_client_walk failed %d\n",
                         err);
-               fid = NULL;
                goto error;
        }
 
@@ -905,9 +885,8 @@ v9fs_vfs_mknod_dotl(struct user_namespace *mnt_userns, struct inode *dir,
                        goto error;
                }
                v9fs_set_create_acl(inode, fid, dacl, pacl);
-               v9fs_fid_add(dentry, fid);
+               v9fs_fid_add(dentry, &fid);
                d_instantiate(dentry, inode);
-               fid = NULL;
                err = 0;
        } else {
                /*
@@ -923,8 +902,7 @@ v9fs_vfs_mknod_dotl(struct user_namespace *mnt_userns, struct inode *dir,
                d_instantiate(dentry, inode);
        }
 error:
-       if (fid)
-               p9_fid_put(fid);
+       p9_fid_put(fid);
        v9fs_put_acl(dacl, pacl);
        p9_fid_put(dfid);
 

diff --git a/fs/9p/vfs_super.c b/fs/9p/vfs_super.c
index bf350fa..2d9ee07 100644 (file)
--- a/fs/9p/vfs_super.c
+++ b/fs/9p/vfs_super.c
@@ -184,7 +184,7 @@ static struct dentry *v9fs_mount(struct file_system_type *fs_type, int flags,
        retval = v9fs_get_acl(inode, fid);
        if (retval)
                goto release_sb;
-       v9fs_fid_add(root, fid);
+       v9fs_fid_add(root, &fid);
 
        p9_debug(P9_DEBUG_VFS, " simple set mount, return 0\n");
        return dget(sb->s_root);