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/* SPDX-License-Identifier: GPL-2.0-only */
/*
*
* Copyright (C) 2011 Novell Inc.
* Copyright (C) 2016 Red Hat, Inc.
*/
struct ovl_config {
char *upperdir;
char *workdir;
bool default_permissions;
int redirect_mode;
int verity_mode;
bool index;
int uuid;
bool nfs_export;
int xino;
bool metacopy;
bool userxattr;
bool ovl_volatile;
};
struct ovl_sb {
struct super_block *sb;
dev_t pseudo_dev;
/* Unusable (conflicting) uuid */
bool bad_uuid;
/* Used as a lower layer (but maybe also as upper) */
bool is_lower;
};
struct ovl_layer {
/* ovl_free_fs() relies on @mnt being the first member! */
struct vfsmount *mnt;
/* Trap in ovl inode cache */
struct inode *trap;
struct ovl_sb *fs;
/* Index of this layer in fs root (upper idx == 0) */
int idx;
/* One fsid per unique underlying sb (upper fsid == 0) */
int fsid;
char *name;
};
/*
* ovl_free_fs() relies on @mnt being the first member when unmounting
* the private mounts created for each layer. Let's check both the
* offset and type.
*/
static_assert(offsetof(struct ovl_layer, mnt) == 0);
static_assert(__same_type(typeof_member(struct ovl_layer, mnt), struct vfsmount *));
struct ovl_path {
const struct ovl_layer *layer;
struct dentry *dentry;
};
struct ovl_entry {
unsigned int __numlower;
struct ovl_path __lowerstack[];
};
/* private information held for overlayfs's superblock */
struct ovl_fs {
unsigned int numlayer;
/* Number of unique fs among layers including upper fs */
unsigned int numfs;
/* Number of data-only lower layers */
unsigned int numdatalayer;
const struct ovl_layer *layers;
struct ovl_sb *fs;
/* workbasedir is the path at workdir= mount option */
struct dentry *workbasedir;
/* workdir is the 'work' directory under workbasedir */
struct dentry *workdir;
/* index directory listing overlay inodes by origin file handle */
struct dentry *indexdir;
long namelen;
/* pathnames of lower and upper dirs, for show_options */
struct ovl_config config;
/* creds of process who forced instantiation of super block */
const struct cred *creator_cred;
bool tmpfile;
bool noxattr;
bool nofh;
/* Did we take the inuse lock? */
bool upperdir_locked;
bool workdir_locked;
/* Traps in ovl inode cache */
struct inode *workbasedir_trap;
struct inode *workdir_trap;
struct inode *indexdir_trap;
/* -1: disabled, 0: same fs, 1..32: number of unused ino bits */
int xino_mode;
/* For allocation of non-persistent inode numbers */
atomic_long_t last_ino;
/* Shared whiteout cache */
struct dentry *whiteout;
bool no_shared_whiteout;
/* r/o snapshot of upperdir sb's only taken on volatile mounts */
errseq_t errseq;
};
/* Number of lower layers, not including data-only layers */
static inline unsigned int ovl_numlowerlayer(struct ovl_fs *ofs)
{
return ofs->numlayer - ofs->numdatalayer - 1;
}
static inline struct vfsmount *ovl_upper_mnt(struct ovl_fs *ofs)
{
return ofs->layers[0].mnt;
}
static inline struct mnt_idmap *ovl_upper_mnt_idmap(struct ovl_fs *ofs)
{
return mnt_idmap(ovl_upper_mnt(ofs));
}
extern struct file_system_type ovl_fs_type;
static inline struct ovl_fs *OVL_FS(struct super_block *sb)
{
if (IS_ENABLED(CONFIG_OVERLAY_FS_DEBUG))
WARN_ON_ONCE(sb->s_type != &ovl_fs_type);
return (struct ovl_fs *)sb->s_fs_info;
}
static inline bool ovl_should_sync(struct ovl_fs *ofs)
{
return !ofs->config.ovl_volatile;
}
static inline unsigned int ovl_numlower(struct ovl_entry *oe)
{
return oe ? oe->__numlower : 0;
}
static inline struct ovl_path *ovl_lowerstack(struct ovl_entry *oe)
{
return ovl_numlower(oe) ? oe->__lowerstack : NULL;
}
static inline struct ovl_path *ovl_lowerpath(struct ovl_entry *oe)
{
return ovl_lowerstack(oe);
}
static inline struct ovl_path *ovl_lowerdata(struct ovl_entry *oe)
{
struct ovl_path *lowerstack = ovl_lowerstack(oe);
return lowerstack ? &lowerstack[oe->__numlower - 1] : NULL;
}
/* May return NULL if lazy lookup of lowerdata is needed */
static inline struct dentry *ovl_lowerdata_dentry(struct ovl_entry *oe)
{
struct ovl_path *lowerdata = ovl_lowerdata(oe);
return lowerdata ? READ_ONCE(lowerdata->dentry) : NULL;
}
/* private information held for every overlayfs dentry */
static inline unsigned long *OVL_E_FLAGS(struct dentry *dentry)
{
return (unsigned long *) &dentry->d_fsdata;
}
struct ovl_inode {
union {
struct ovl_dir_cache *cache; /* directory */
const char *lowerdata_redirect; /* regular file */
};
const char *redirect;
u64 version;
unsigned long flags;
struct inode vfs_inode;
struct dentry *__upperdentry;
struct ovl_entry *oe;
/* synchronize copy up and more */
struct mutex lock;
};
static inline struct ovl_inode *OVL_I(struct inode *inode)
{
return container_of(inode, struct ovl_inode, vfs_inode);
}
static inline struct ovl_entry *OVL_I_E(struct inode *inode)
{
return inode ? OVL_I(inode)->oe : NULL;
}
static inline struct ovl_entry *OVL_E(struct dentry *dentry)
{
return OVL_I_E(d_inode(dentry));
}
static inline struct dentry *ovl_upperdentry_dereference(struct ovl_inode *oi)
{
return READ_ONCE(oi->__upperdentry);
}
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