/* SPDX-License-Identifier: GPL-2.0 */
/*
* Copyright (C) 2005-2019 Junjiro R. Okajima
*
* This program, aufs is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see .
*/
/*
* super_block operations
*/
#ifndef __AUFS_SUPER_H__
#define __AUFS_SUPER_H__
#ifdef __KERNEL__
#include
#include
#include "hbl.h"
#include "lcnt.h"
#include "rwsem.h"
#include "wkq.h"
/* policies to select one among multiple writable branches */
struct au_wbr_copyup_operations {
int (*copyup)(struct dentry *dentry);
};
#define AuWbr_DIR 1 /* target is a dir */
#define AuWbr_PARENT (1 << 1) /* always require a parent */
#define au_ftest_wbr(flags, name) ((flags) & AuWbr_##name)
#define au_fset_wbr(flags, name) { (flags) |= AuWbr_##name; }
#define au_fclr_wbr(flags, name) { (flags) &= ~AuWbr_##name; }
struct au_wbr_create_operations {
int (*create)(struct dentry *dentry, unsigned int flags);
int (*init)(struct super_block *sb);
int (*fin)(struct super_block *sb);
};
struct au_wbr_mfs {
struct mutex mfs_lock; /* protect this structure */
unsigned long mfs_jiffy;
unsigned long mfs_expire;
aufs_bindex_t mfs_bindex;
unsigned long long mfsrr_bytes;
unsigned long long mfsrr_watermark;
};
#define AuPlink_NHASH 100
static inline int au_plink_hash(ino_t ino)
{
return ino % AuPlink_NHASH;
}
/* File-based Hierarchical Storage Management */
struct au_fhsm {
#ifdef CONFIG_AUFS_FHSM
/* allow only one process who can receive the notification */
spinlock_t fhsm_spin;
pid_t fhsm_pid;
wait_queue_head_t fhsm_wqh;
atomic_t fhsm_readable;
/* these are protected by si_rwsem */
unsigned long fhsm_expire;
aufs_bindex_t fhsm_bottom;
#endif
};
struct au_branch;
struct au_sbinfo {
/* nowait tasks in the system-wide workqueue */
struct au_nowait_tasks si_nowait;
/*
* tried sb->s_umount, but failed due to the dependency between i_mutex.
* rwsem for au_sbinfo is necessary.
*/
struct au_rwsem si_rwsem;
/*
* dirty approach to protect sb->sb_inodes and ->s_files (gone) from
* remount.
*/
au_lcnt_t si_ninodes, si_nfiles;
/* branch management */
unsigned int si_generation;
/* see AuSi_ flags */
unsigned char au_si_status;
aufs_bindex_t si_bbot;
/* dirty trick to keep br_id plus */
unsigned int si_last_br_id :
sizeof(aufs_bindex_t) * BITS_PER_BYTE - 1;
struct au_branch **si_branch;
/* policy to select a writable branch */
unsigned char si_wbr_copyup;
unsigned char si_wbr_create;
struct au_wbr_copyup_operations *si_wbr_copyup_ops;
struct au_wbr_create_operations *si_wbr_create_ops;
/* round robin */
atomic_t si_wbr_rr_next;
/* most free space */
struct au_wbr_mfs si_wbr_mfs;
/* File-based Hierarchical Storage Management */
struct au_fhsm si_fhsm;
/* mount flags */
/* include/asm-ia64/siginfo.h defines a macro named si_flags */
unsigned int si_mntflags;
/* external inode number (bitmap and translation table) */
vfs_readf_t si_xread;
vfs_writef_t si_xwrite;
loff_t si_ximaxent; /* max entries in a xino */
struct file *si_xib;
struct mutex si_xib_mtx; /* protect xib members */
unsigned long *si_xib_buf;
unsigned long si_xib_last_pindex;
int si_xib_next_bit;
unsigned long si_xino_jiffy;
unsigned long si_xino_expire;
/* reserved for future use */
/* unsigned long long si_xib_limit; */ /* Max xib file size */
#ifdef CONFIG_AUFS_EXPORT
/* i_generation */
/* todo: make xigen file an array to support many inode numbers */
struct file *si_xigen;
atomic_t si_xigen_next;
#endif
/* dirty trick to support atomic_open */
struct hlist_bl_head si_aopen;
/* vdir parameters */
unsigned long si_rdcache; /* max cache time in jiffies */
unsigned int si_rdblk; /* deblk size */
unsigned int si_rdhash; /* hash size */
/*
* If the number of whiteouts are larger than si_dirwh, leave all of
* them after au_whtmp_ren to reduce the cost of rmdir(2).
* future fsck.aufs or kernel thread will remove them later.
* Otherwise, remove all whiteouts and the dir in rmdir(2).
*/
unsigned int si_dirwh;
/* pseudo_link list */
struct hlist_bl_head si_plink[AuPlink_NHASH];
wait_queue_head_t si_plink_wq;
spinlock_t si_plink_maint_lock;
pid_t si_plink_maint_pid;
/* file list */
struct hlist_bl_head si_files;
/* with/without getattr, brother of sb->s_d_op */
const struct inode_operations *si_iop_array;
/*
* sysfs and lifetime management.
* this is not a small structure and it may be a waste of memory in case
* of sysfs is disabled, particularly when many aufs-es are mounted.
* but using sysfs is majority.
*/
struct kobject si_kobj;
#ifdef CONFIG_DEBUG_FS
struct dentry *si_dbgaufs;
struct dentry *si_dbgaufs_plink;
struct dentry *si_dbgaufs_xib;
#ifdef CONFIG_AUFS_EXPORT
struct dentry *si_dbgaufs_xigen;
#endif
#endif
#ifdef CONFIG_AUFS_SBILIST
struct hlist_bl_node si_list;
#endif
/* dirty, necessary for unmounting, sysfs and sysrq */
struct super_block *si_sb;
};
/* sbinfo status flags */
/*
* set true when refresh_dirs() failed at remount time.
* then try refreshing dirs at access time again.
* if it is false, refreshing dirs at access time is unnecessary
*/
#define AuSi_FAILED_REFRESH_DIR 1
#define AuSi_FHSM (1 << 1) /* fhsm is active now */
#define AuSi_NO_DREVAL (1 << 2) /* disable all d_revalidate */
#ifndef CONFIG_AUFS_FHSM
#undef AuSi_FHSM
#define AuSi_FHSM 0
#endif
static inline unsigned char au_do_ftest_si(struct au_sbinfo *sbi,
unsigned int flag)
{
AuRwMustAnyLock(&sbi->si_rwsem);
return sbi->au_si_status & flag;
}
#define au_ftest_si(sbinfo, name) au_do_ftest_si(sbinfo, AuSi_##name)
#define au_fset_si(sbinfo, name) do { \
AuRwMustWriteLock(&(sbinfo)->si_rwsem); \
(sbinfo)->au_si_status |= AuSi_##name; \
} while (0)
#define au_fclr_si(sbinfo, name) do { \
AuRwMustWriteLock(&(sbinfo)->si_rwsem); \
(sbinfo)->au_si_status &= ~AuSi_##name; \
} while (0)
/* ---------------------------------------------------------------------- */
/* policy to select one among writable branches */
#define AuWbrCopyup(sbinfo, ...) \
((sbinfo)->si_wbr_copyup_ops->copyup(__VA_ARGS__))
#define AuWbrCreate(sbinfo, ...) \
((sbinfo)->si_wbr_create_ops->create(__VA_ARGS__))
/* flags for si_read_lock()/aufs_read_lock()/di_read_lock() */
#define AuLock_DW 1 /* write-lock dentry */
#define AuLock_IR (1 << 1) /* read-lock inode */
#define AuLock_IW (1 << 2) /* write-lock inode */
#define AuLock_FLUSH (1 << 3) /* wait for 'nowait' tasks */
#define AuLock_DIRS (1 << 4) /* target is a pair of dirs */
/* except RENAME_EXCHANGE */
#define AuLock_NOPLM (1 << 5) /* return err in plm mode */
#define AuLock_NOPLMW (1 << 6) /* wait for plm mode ends */
#define AuLock_GEN (1 << 7) /* test digen/iigen */
#define au_ftest_lock(flags, name) ((flags) & AuLock_##name)
#define au_fset_lock(flags, name) \
do { (flags) |= AuLock_##name; } while (0)
#define au_fclr_lock(flags, name) \
do { (flags) &= ~AuLock_##name; } while (0)
/* ---------------------------------------------------------------------- */
/* super.c */
extern struct file_system_type aufs_fs_type;
struct inode *au_iget_locked(struct super_block *sb, ino_t ino);
typedef unsigned long long (*au_arraycb_t)(struct super_block *sb, void *array,
unsigned long long max, void *arg);
void *au_array_alloc(unsigned long long *hint, au_arraycb_t cb,
struct super_block *sb, void *arg);
struct inode **au_iarray_alloc(struct super_block *sb, unsigned long long *max);
void au_iarray_free(struct inode **a, unsigned long long max);
/* sbinfo.c */
void au_si_free(struct kobject *kobj);
int au_si_alloc(struct super_block *sb);
int au_sbr_realloc(struct au_sbinfo *sbinfo, int nbr, int may_shrink);
unsigned int au_sigen_inc(struct super_block *sb);
aufs_bindex_t au_new_br_id(struct super_block *sb);
int si_read_lock(struct super_block *sb, int flags);
int si_write_lock(struct super_block *sb, int flags);
int aufs_read_lock(struct dentry *dentry, int flags);
void aufs_read_unlock(struct dentry *dentry, int flags);
void aufs_write_lock(struct dentry *dentry);
void aufs_write_unlock(struct dentry *dentry);
int aufs_read_and_write_lock2(struct dentry *d1, struct dentry *d2, int flags);
void aufs_read_and_write_unlock2(struct dentry *d1, struct dentry *d2);
/* wbr_policy.c */
extern struct au_wbr_copyup_operations au_wbr_copyup_ops[];
extern struct au_wbr_create_operations au_wbr_create_ops[];
int au_cpdown_dirs(struct dentry *dentry, aufs_bindex_t bdst);
int au_wbr_nonopq(struct dentry *dentry, aufs_bindex_t bindex);
int au_wbr_do_copyup_bu(struct dentry *dentry, aufs_bindex_t btop);
/* mvdown.c */
int au_mvdown(struct dentry *dentry, struct aufs_mvdown __user *arg);
#ifdef CONFIG_AUFS_FHSM
/* fhsm.c */
static inline pid_t au_fhsm_pid(struct au_fhsm *fhsm)
{
pid_t pid;
spin_lock(&fhsm->fhsm_spin);
pid = fhsm->fhsm_pid;
spin_unlock(&fhsm->fhsm_spin);
return pid;
}
void au_fhsm_wrote(struct super_block *sb, aufs_bindex_t bindex, int force);
void au_fhsm_wrote_all(struct super_block *sb, int force);
int au_fhsm_fd(struct super_block *sb, int oflags);
int au_fhsm_br_alloc(struct au_branch *br);
void au_fhsm_set_bottom(struct super_block *sb, aufs_bindex_t bindex);
void au_fhsm_fin(struct super_block *sb);
void au_fhsm_init(struct au_sbinfo *sbinfo);
void au_fhsm_set(struct au_sbinfo *sbinfo, unsigned int sec);
void au_fhsm_show(struct seq_file *seq, struct au_sbinfo *sbinfo);
#else
AuStubVoid(au_fhsm_wrote, struct super_block *sb, aufs_bindex_t bindex,
int force)
AuStubVoid(au_fhsm_wrote_all, struct super_block *sb, int force)
AuStub(int, au_fhsm_fd, return -EOPNOTSUPP, struct super_block *sb, int oflags)
AuStub(pid_t, au_fhsm_pid, return 0, struct au_fhsm *fhsm)
AuStubInt0(au_fhsm_br_alloc, struct au_branch *br)
AuStubVoid(au_fhsm_set_bottom, struct super_block *sb, aufs_bindex_t bindex)
AuStubVoid(au_fhsm_fin, struct super_block *sb)
AuStubVoid(au_fhsm_init, struct au_sbinfo *sbinfo)
AuStubVoid(au_fhsm_set, struct au_sbinfo *sbinfo, unsigned int sec)
AuStubVoid(au_fhsm_show, struct seq_file *seq, struct au_sbinfo *sbinfo)
#endif
/* ---------------------------------------------------------------------- */
static inline struct au_sbinfo *au_sbi(struct super_block *sb)
{
return sb->s_fs_info;
}
/* ---------------------------------------------------------------------- */
#ifdef CONFIG_AUFS_EXPORT
int au_test_nfsd(void);
void au_export_init(struct super_block *sb);
void au_xigen_inc(struct inode *inode);
int au_xigen_new(struct inode *inode);
int au_xigen_set(struct super_block *sb, struct path *path);
void au_xigen_clr(struct super_block *sb);
static inline int au_busy_or_stale(void)
{
if (!au_test_nfsd())
return -EBUSY;
return -ESTALE;
}
#else
AuStubInt0(au_test_nfsd, void)
AuStubVoid(au_export_init, struct super_block *sb)
AuStubVoid(au_xigen_inc, struct inode *inode)
AuStubInt0(au_xigen_new, struct inode *inode)
AuStubInt0(au_xigen_set, struct super_block *sb, struct path *path)
AuStubVoid(au_xigen_clr, struct super_block *sb)
AuStub(int, au_busy_or_stale, return -EBUSY, void)
#endif /* CONFIG_AUFS_EXPORT */
/* ---------------------------------------------------------------------- */
#ifdef CONFIG_AUFS_SBILIST
/* module.c */
extern struct hlist_bl_head au_sbilist;
static inline void au_sbilist_init(void)
{
INIT_HLIST_BL_HEAD(&au_sbilist);
}
static inline void au_sbilist_add(struct super_block *sb)
{
au_hbl_add(&au_sbi(sb)->si_list, &au_sbilist);
}
static inline void au_sbilist_del(struct super_block *sb)
{
au_hbl_del(&au_sbi(sb)->si_list, &au_sbilist);
}
#ifdef CONFIG_AUFS_MAGIC_SYSRQ
static inline void au_sbilist_lock(void)
{
hlist_bl_lock(&au_sbilist);
}
static inline void au_sbilist_unlock(void)
{
hlist_bl_unlock(&au_sbilist);
}
#define AuGFP_SBILIST GFP_ATOMIC
#else
AuStubVoid(au_sbilist_lock, void)
AuStubVoid(au_sbilist_unlock, void)
#define AuGFP_SBILIST GFP_NOFS
#endif /* CONFIG_AUFS_MAGIC_SYSRQ */
#else
AuStubVoid(au_sbilist_init, void)
AuStubVoid(au_sbilist_add, struct super_block *sb)
AuStubVoid(au_sbilist_del, struct super_block *sb)
AuStubVoid(au_sbilist_lock, void)
AuStubVoid(au_sbilist_unlock, void)
#define AuGFP_SBILIST GFP_NOFS
#endif
/* ---------------------------------------------------------------------- */
static inline void dbgaufs_si_null(struct au_sbinfo *sbinfo)
{
/*
* This function is a dynamic '__init' function actually,
* so the tiny check for si_rwsem is unnecessary.
*/
/* AuRwMustWriteLock(&sbinfo->si_rwsem); */
#ifdef CONFIG_DEBUG_FS
sbinfo->si_dbgaufs = NULL;
sbinfo->si_dbgaufs_plink = NULL;
sbinfo->si_dbgaufs_xib = NULL;
#ifdef CONFIG_AUFS_EXPORT
sbinfo->si_dbgaufs_xigen = NULL;
#endif
#endif
}
/* ---------------------------------------------------------------------- */
/* current->atomic_flags */
/* this value should never corrupt the ones defined in linux/sched.h */
#define PFA_AUFS 7
TASK_PFA_TEST(AUFS, test_aufs) /* task_test_aufs */
TASK_PFA_SET(AUFS, aufs) /* task_set_aufs */
TASK_PFA_CLEAR(AUFS, aufs) /* task_clear_aufs */
static inline int si_pid_test(struct super_block *sb)
{
return !!task_test_aufs(current);
}
static inline void si_pid_clr(struct super_block *sb)
{
AuDebugOn(!task_test_aufs(current));
task_clear_aufs(current);
}
static inline void si_pid_set(struct super_block *sb)
{
AuDebugOn(task_test_aufs(current));
task_set_aufs(current);
}
/* ---------------------------------------------------------------------- */
/* lock superblock. mainly for entry point functions */
#define __si_read_lock(sb) au_rw_read_lock(&au_sbi(sb)->si_rwsem)
#define __si_write_lock(sb) au_rw_write_lock(&au_sbi(sb)->si_rwsem)
#define __si_read_trylock(sb) au_rw_read_trylock(&au_sbi(sb)->si_rwsem)
#define __si_write_trylock(sb) au_rw_write_trylock(&au_sbi(sb)->si_rwsem)
/*
#define __si_read_trylock_nested(sb) \
au_rw_read_trylock_nested(&au_sbi(sb)->si_rwsem)
#define __si_write_trylock_nested(sb) \
au_rw_write_trylock_nested(&au_sbi(sb)->si_rwsem)
*/
#define __si_read_unlock(sb) au_rw_read_unlock(&au_sbi(sb)->si_rwsem)
#define __si_write_unlock(sb) au_rw_write_unlock(&au_sbi(sb)->si_rwsem)
#define __si_downgrade_lock(sb) au_rw_dgrade_lock(&au_sbi(sb)->si_rwsem)
#define SiMustNoWaiters(sb) AuRwMustNoWaiters(&au_sbi(sb)->si_rwsem)
#define SiMustAnyLock(sb) AuRwMustAnyLock(&au_sbi(sb)->si_rwsem)
#define SiMustWriteLock(sb) AuRwMustWriteLock(&au_sbi(sb)->si_rwsem)
static inline void si_noflush_read_lock(struct super_block *sb)
{
__si_read_lock(sb);
si_pid_set(sb);
}
static inline int si_noflush_read_trylock(struct super_block *sb)
{
int locked;
locked = __si_read_trylock(sb);
if (locked)
si_pid_set(sb);
return locked;
}
static inline void si_noflush_write_lock(struct super_block *sb)
{
__si_write_lock(sb);
si_pid_set(sb);
}
static inline int si_noflush_write_trylock(struct super_block *sb)
{
int locked;
locked = __si_write_trylock(sb);
if (locked)
si_pid_set(sb);
return locked;
}
#if 0 /* reserved */
static inline int si_read_trylock(struct super_block *sb, int flags)
{
if (au_ftest_lock(flags, FLUSH))
au_nwt_flush(&au_sbi(sb)->si_nowait);
return si_noflush_read_trylock(sb);
}
#endif
static inline void si_read_unlock(struct super_block *sb)
{
si_pid_clr(sb);
__si_read_unlock(sb);
}
#if 0 /* reserved */
static inline int si_write_trylock(struct super_block *sb, int flags)
{
if (au_ftest_lock(flags, FLUSH))
au_nwt_flush(&au_sbi(sb)->si_nowait);
return si_noflush_write_trylock(sb);
}
#endif
static inline void si_write_unlock(struct super_block *sb)
{
si_pid_clr(sb);
__si_write_unlock(sb);
}
#if 0 /* reserved */
static inline void si_downgrade_lock(struct super_block *sb)
{
__si_downgrade_lock(sb);
}
#endif
/* ---------------------------------------------------------------------- */
static inline aufs_bindex_t au_sbbot(struct super_block *sb)
{
SiMustAnyLock(sb);
return au_sbi(sb)->si_bbot;
}
static inline unsigned int au_mntflags(struct super_block *sb)
{
SiMustAnyLock(sb);
return au_sbi(sb)->si_mntflags;
}
static inline unsigned int au_sigen(struct super_block *sb)
{
SiMustAnyLock(sb);
return au_sbi(sb)->si_generation;
}
static inline struct au_branch *au_sbr(struct super_block *sb,
aufs_bindex_t bindex)
{
SiMustAnyLock(sb);
return au_sbi(sb)->si_branch[0 + bindex];
}
static inline loff_t au_xi_maxent(struct super_block *sb)
{
SiMustAnyLock(sb);
return au_sbi(sb)->si_ximaxent;
}
#endif /* __KERNEL__ */
#endif /* __AUFS_SUPER_H__ */