[PATCH] ovl: make consistent use of OVL_FS()
From: Andrea Righi
Date: Sat May 20 2023 - 08:05:42 EST
Always use OVL_FS() to retrieve the corresponding struct ovl_fs from a
struct super_block and make sure that it is exclusively used with an
overlayfs superblock (otherwise, trigger a BUG).
Signed-off-by: Andrea Righi <andrea.righi@xxxxxxxxxxxxx>
---
fs/overlayfs/copy_up.c | 2 +-
fs/overlayfs/export.c | 10 +++++-----
fs/overlayfs/inode.c | 8 ++++----
fs/overlayfs/namei.c | 2 +-
fs/overlayfs/ovl_entry.h | 4 ++++
fs/overlayfs/super.c | 10 +++++-----
fs/overlayfs/util.c | 18 +++++++++---------
7 files changed, 29 insertions(+), 25 deletions(-)
diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c
index f658cc8ea492..60aa615820e7 100644
--- a/fs/overlayfs/copy_up.c
+++ b/fs/overlayfs/copy_up.c
@@ -905,7 +905,7 @@ static int ovl_do_copy_up(struct ovl_copy_up_ctx *c)
static bool ovl_need_meta_copy_up(struct dentry *dentry, umode_t mode,
int flags)
{
- struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
+ struct ovl_fs *ofs = OVL_FS(dentry->d_sb);
if (!ofs->config.metacopy)
return false;
diff --git a/fs/overlayfs/export.c b/fs/overlayfs/export.c
index defd4e231ad2..f5f0ef8e3ce8 100644
--- a/fs/overlayfs/export.c
+++ b/fs/overlayfs/export.c
@@ -182,7 +182,7 @@ static int ovl_connect_layer(struct dentry *dentry)
*/
static int ovl_check_encode_origin(struct dentry *dentry)
{
- struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
+ struct ovl_fs *ofs = OVL_FS(dentry->d_sb);
/* Upper file handle for pure upper */
if (!ovl_dentry_lower(dentry))
@@ -434,7 +434,7 @@ static struct dentry *ovl_lookup_real_inode(struct super_block *sb,
struct dentry *real,
const struct ovl_layer *layer)
{
- struct ovl_fs *ofs = sb->s_fs_info;
+ struct ovl_fs *ofs = OVL_FS(sb);
struct dentry *index = NULL;
struct dentry *this = NULL;
struct inode *inode;
@@ -655,7 +655,7 @@ static struct dentry *ovl_get_dentry(struct super_block *sb,
struct ovl_path *lowerpath,
struct dentry *index)
{
- struct ovl_fs *ofs = sb->s_fs_info;
+ struct ovl_fs *ofs = OVL_FS(sb);
const struct ovl_layer *layer = upper ? &ofs->layers[0] : lowerpath->layer;
struct dentry *real = upper ?: (index ?: lowerpath->dentry);
@@ -680,7 +680,7 @@ static struct dentry *ovl_get_dentry(struct super_block *sb,
static struct dentry *ovl_upper_fh_to_d(struct super_block *sb,
struct ovl_fh *fh)
{
- struct ovl_fs *ofs = sb->s_fs_info;
+ struct ovl_fs *ofs = OVL_FS(sb);
struct dentry *dentry;
struct dentry *upper;
@@ -700,7 +700,7 @@ static struct dentry *ovl_upper_fh_to_d(struct super_block *sb,
static struct dentry *ovl_lower_fh_to_d(struct super_block *sb,
struct ovl_fh *fh)
{
- struct ovl_fs *ofs = sb->s_fs_info;
+ struct ovl_fs *ofs = OVL_FS(sb);
struct ovl_path origin = { };
struct ovl_path *stack = &origin;
struct dentry *dentry = NULL;
diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
index 541cf3717fc2..c27823f6e7aa 100644
--- a/fs/overlayfs/inode.c
+++ b/fs/overlayfs/inode.c
@@ -334,7 +334,7 @@ static const char *ovl_get_link(struct dentry *dentry,
bool ovl_is_private_xattr(struct super_block *sb, const char *name)
{
- struct ovl_fs *ofs = sb->s_fs_info;
+ struct ovl_fs *ofs = OVL_FS(sb);
if (ofs->config.userxattr)
return strncmp(name, OVL_XATTR_USER_PREFIX,
@@ -689,7 +689,7 @@ int ovl_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
int ovl_update_time(struct inode *inode, struct timespec64 *ts, int flags)
{
if (flags & S_ATIME) {
- struct ovl_fs *ofs = inode->i_sb->s_fs_info;
+ struct ovl_fs *ofs = OVL_FS(inode->i_sb);
struct path upperpath = {
.mnt = ovl_upper_mnt(ofs),
.dentry = ovl_upperdentry_dereference(OVL_I(inode)),
@@ -952,7 +952,7 @@ static inline void ovl_lockdep_annotate_inode_mutex_key(struct inode *inode)
static void ovl_next_ino(struct inode *inode)
{
- struct ovl_fs *ofs = inode->i_sb->s_fs_info;
+ struct ovl_fs *ofs = OVL_FS(inode->i_sb);
inode->i_ino = atomic_long_inc_return(&ofs->last_ino);
if (unlikely(!inode->i_ino))
@@ -1284,7 +1284,7 @@ struct inode *ovl_get_trap_inode(struct super_block *sb, struct dentry *dir)
static bool ovl_hash_bylower(struct super_block *sb, struct dentry *upper,
struct dentry *lower, bool index)
{
- struct ovl_fs *ofs = sb->s_fs_info;
+ struct ovl_fs *ofs = OVL_FS(sb);
/* No, if pure upper */
if (!lower)
diff --git a/fs/overlayfs/namei.c b/fs/overlayfs/namei.c
index cfb3420b7df0..d0f196b85541 100644
--- a/fs/overlayfs/namei.c
+++ b/fs/overlayfs/namei.c
@@ -832,7 +832,7 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
{
struct ovl_entry *oe;
const struct cred *old_cred;
- struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
+ struct ovl_fs *ofs = OVL_FS(dentry->d_sb);
struct ovl_entry *poe = dentry->d_parent->d_fsdata;
struct ovl_entry *roe = dentry->d_sb->s_root->d_fsdata;
struct ovl_path *stack = NULL, *origin_path = NULL;
diff --git a/fs/overlayfs/ovl_entry.h b/fs/overlayfs/ovl_entry.h
index fd11fe6d6d45..b91b3694ae26 100644
--- a/fs/overlayfs/ovl_entry.h
+++ b/fs/overlayfs/ovl_entry.h
@@ -5,6 +5,8 @@
* Copyright (C) 2016 Red Hat, Inc.
*/
+#include <uapi/linux/magic.h>
+
struct ovl_config {
char *lowerdir;
char *upperdir;
@@ -97,6 +99,8 @@ static inline struct mnt_idmap *ovl_upper_mnt_idmap(struct ovl_fs *ofs)
static inline struct ovl_fs *OVL_FS(struct super_block *sb)
{
+ /* Make sure OVL_FS() is always used with an overlayfs superblock */
+ BUG_ON(sb->s_magic != OVERLAYFS_SUPER_MAGIC);
return (struct ovl_fs *)sb->s_fs_info;
}
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index f97ad8b40dbb..879d601ba61e 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -259,7 +259,7 @@ static void ovl_free_fs(struct ovl_fs *ofs)
static void ovl_put_super(struct super_block *sb)
{
- struct ovl_fs *ofs = sb->s_fs_info;
+ struct ovl_fs *ofs = OVL_FS(sb);
ovl_free_fs(ofs);
}
@@ -267,7 +267,7 @@ static void ovl_put_super(struct super_block *sb)
/* Sync real dirty inodes in upper filesystem (if it exists) */
static int ovl_sync_fs(struct super_block *sb, int wait)
{
- struct ovl_fs *ofs = sb->s_fs_info;
+ struct ovl_fs *ofs = OVL_FS(sb);
struct super_block *upper_sb;
int ret;
@@ -315,7 +315,7 @@ static int ovl_sync_fs(struct super_block *sb, int wait)
*/
static int ovl_statfs(struct dentry *dentry, struct kstatfs *buf)
{
- struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
+ struct ovl_fs *ofs = OVL_FS(dentry->d_sb);
struct dentry *root_dentry = dentry->d_sb->s_root;
struct path path;
int err;
@@ -364,7 +364,7 @@ static inline int ovl_xino_def(void)
static int ovl_show_options(struct seq_file *m, struct dentry *dentry)
{
struct super_block *sb = dentry->d_sb;
- struct ovl_fs *ofs = sb->s_fs_info;
+ struct ovl_fs *ofs = OVL_FS(sb);
seq_show_option(m, "lowerdir", ofs->config.lowerdir);
if (ofs->config.upperdir) {
@@ -396,7 +396,7 @@ static int ovl_show_options(struct seq_file *m, struct dentry *dentry)
static int ovl_remount(struct super_block *sb, int *flags, char *data)
{
- struct ovl_fs *ofs = sb->s_fs_info;
+ struct ovl_fs *ofs = OVL_FS(sb);
struct super_block *upper_sb;
int ret = 0;
diff --git a/fs/overlayfs/util.c b/fs/overlayfs/util.c
index 923d66d131c1..2425240ef139 100644
--- a/fs/overlayfs/util.c
+++ b/fs/overlayfs/util.c
@@ -18,25 +18,25 @@
int ovl_want_write(struct dentry *dentry)
{
- struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
+ struct ovl_fs *ofs = OVL_FS(dentry->d_sb);
return mnt_want_write(ovl_upper_mnt(ofs));
}
void ovl_drop_write(struct dentry *dentry)
{
- struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
+ struct ovl_fs *ofs = OVL_FS(dentry->d_sb);
mnt_drop_write(ovl_upper_mnt(ofs));
}
struct dentry *ovl_workdir(struct dentry *dentry)
{
- struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
+ struct ovl_fs *ofs = OVL_FS(dentry->d_sb);
return ofs->workdir;
}
const struct cred *ovl_override_creds(struct super_block *sb)
{
- struct ovl_fs *ofs = sb->s_fs_info;
+ struct ovl_fs *ofs = OVL_FS(sb);
return override_creds(ofs->creator_cred);
}
@@ -62,7 +62,7 @@ int ovl_can_decode_fh(struct super_block *sb)
struct dentry *ovl_indexdir(struct super_block *sb)
{
- struct ovl_fs *ofs = sb->s_fs_info;
+ struct ovl_fs *ofs = OVL_FS(sb);
return ofs->indexdir;
}
@@ -70,7 +70,7 @@ struct dentry *ovl_indexdir(struct super_block *sb)
/* Index all files on copy up. For now only enabled for NFS export */
bool ovl_index_all(struct super_block *sb)
{
- struct ovl_fs *ofs = sb->s_fs_info;
+ struct ovl_fs *ofs = OVL_FS(sb);
return ofs->config.nfs_export && ofs->config.index;
}
@@ -78,7 +78,7 @@ bool ovl_index_all(struct super_block *sb)
/* Verify lower origin on lookup. For now only enabled for NFS export */
bool ovl_verify_lower(struct super_block *sb)
{
- struct ovl_fs *ofs = sb->s_fs_info;
+ struct ovl_fs *ofs = OVL_FS(sb);
return ofs->config.nfs_export && ofs->config.index;
}
@@ -152,7 +152,7 @@ enum ovl_path_type ovl_path_type(struct dentry *dentry)
void ovl_path_upper(struct dentry *dentry, struct path *path)
{
- struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
+ struct ovl_fs *ofs = OVL_FS(dentry->d_sb);
path->mnt = ovl_upper_mnt(ofs);
path->dentry = ovl_dentry_upper(dentry);
@@ -415,7 +415,7 @@ bool ovl_dentry_needs_data_copy_up(struct dentry *dentry, int flags)
bool ovl_redirect_dir(struct super_block *sb)
{
- struct ovl_fs *ofs = sb->s_fs_info;
+ struct ovl_fs *ofs = OVL_FS(sb);
return ofs->config.redirect_dir && !ofs->noxattr;
}
--
2.39.2