[PATCH 06/06] 9p fid refcount: cleanup p9_fid_put calls

Dominique Martinet
2022-06-12T08:54:43Z

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

Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
---
fs/9p/fid.c | 24 +++++++++++------
fs/9p/fid.h | 4 +--
fs/9p/vfs_file.c | 5 ++--
fs/9p/vfs_inode.c | 61 +++++++++++++++++-------------------------
fs/9p/vfs_inode_dotl.c | 58 +++++++++++++--------------------------
fs/9p/vfs_super.c | 2 +-
6 files changed, 64 insertions(+), 90 deletions(-)

diff --git a/fs/9p/fid.c b/fs/9p/fid.c
index d792499349c4..289a85eae2ae 100644
--- 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 3168dfad510e..8a4e8cd12ca2 100644
--- 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 8276f3af35d7..aec43ba83799 100644
--- 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 38186d1a1440..1b11a92208fd 100644
--- a/fs/9p/vfs_inode.c
+++ b/fs/9p/vfs_inode.c
@@ -398,10 +398,8 @@ 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)
@@ -632,14 +630,12 @@ 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;
}

@@ -650,8 +646,6 @@ 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;
}
/*
@@ -662,21 +656,17 @@ 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);
}

@@ -803,9 +793,9 @@ 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);
}
@@ -846,7 +836,6 @@ 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;
}

@@ -881,7 +870,7 @@ 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:
@@ -889,8 +878,7 @@ v9fs_vfs_atomic_open(struct inode *dir, struct dentry *dentry,
return err;

error:
- if (fid)
- p9_fid_put(fid);
+ p9_fid_put(fid);
goto out;
}

@@ -938,9 +926,9 @@ 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)
@@ -957,21 +945,22 @@ 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);
@@ -982,7 +971,7 @@ 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) {
/*
@@ -991,14 +980,14 @@ 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))
@@ -1019,12 +1008,10 @@ v9fs_vfs_rename(struct user_namespace *mnt_userns, struct inode *old_dir,
d_move(old_dentry, new_dentry);
}
up_write(&v9ses->rename_sem);
+
+error:
p9_fid_put(newdirfid);
-
-clunk_olddir:
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 09b124fe349c..5cfa4b4f070f 100644
--- 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 bf350fad9500..2d9ee073d12c 100644
--- 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);
--
2.35.1