C++ au_sbi函数代码示例

int au_wkq_nowait(au_wkq_func_t func, void *args, struct super_block *sb)
{
	int err;
	struct au_wkinfo *wkinfo;

	atomic_inc(&au_sbi(sb)->si_nowait.nw_len);

	/*
	 * wkq_func() must free this wkinfo.
	 * it highly depends upon the implementation of workqueue.
	 */
	err = 0;
	wkinfo = kmalloc(sizeof(*wkinfo), GFP_NOFS);
	if (wkinfo) {
		wkinfo->sb = sb;
		wkinfo->flags = !AuWkq_WAIT;
		wkinfo->func = func;
		wkinfo->args = args;
		wkinfo->comp = NULL;
		kobject_get(&au_sbi(sb)->si_kobj);
		__module_get(THIS_MODULE);

		au_wkq_run(wkinfo);
	} else {
		err = -ENOMEM;
		atomic_dec(&au_sbi(sb)->si_nowait.nw_len);
	}

	return err;
}

int au_xigen_inc(struct inode *inode)
{
	int err;
	loff_t pos;
	ssize_t sz;
	__u32 igen;
	struct super_block *sb;
	struct au_sbinfo *sbinfo;

	LKTRTrace("i%lu\n", (unsigned long)inode->i_ino);

	err = 0;
	sb = inode->i_sb;
	if (unlikely(!au_opt_test_xino(au_mntflags(sb))))
		goto out;

	pos = inode->i_ino;
	pos *= sizeof(igen);
	igen = inode->i_generation + 1;
	sbinfo = au_sbi(sb);
	sz = xino_fwrite(sbinfo->si_xwrite, sbinfo->si_xigen, &igen,
			 sizeof(igen), &pos);
	if (sz == sizeof(igen))
		goto out; /* success */

	err = sz;
	if (unlikely(sz >= 0)) {
		err = -EIO;
		AuIOErr("xigen error (%zd)\n", sz);
	}

 out:
	AuTraceErr(err);
	return err;
}

static void sysrq_sb(struct super_block *sb)
{
	char *plevel;
	struct au_sbinfo *sbinfo;
	struct file *file;

	plevel = au_plevel;
	au_plevel = KERN_WARNING;
	au_debug(1);

	sbinfo = au_sbi(sb);
	pr_warning("si=%lx\n", sysaufs_si_id(sbinfo));
	pr_warning(AUFS_NAME ": superblock\n");
	au_dpri_sb(sb);
	pr_warning(AUFS_NAME ": root dentry\n");
	au_dpri_dentry(sb->s_root);
	pr_warning(AUFS_NAME ": root inode\n");
	au_dpri_inode(sb->s_root->d_inode);
#if 0
	struct inode *i;
	pr_warning(AUFS_NAME ": isolated inode\n");
	list_for_each_entry(i, &sb->s_inodes, i_sb_list)
		if (list_empty(&i->i_dentry))
			au_dpri_inode(i);
#endif
	pr_warning(AUFS_NAME ": files\n");
	list_for_each_entry(file, &sb->s_files, f_u.fu_list)
		if (!special_file(file->f_dentry->d_inode->i_mode))
			au_dpri_file(file);

	au_plevel = plevel;
	au_debug(0);
}

int au_do_open_nondir(struct file *file, int flags)
{
	int err;
	aufs_bindex_t bindex;
	struct file *h_file;
	struct dentry *dentry;
	struct au_finfo *finfo;

	FiMustWriteLock(file);

	err = 0;
	dentry = file->f_dentry;
	finfo = au_fi(file);
	memset(&finfo->fi_htop, 0, sizeof(finfo->fi_htop));
	atomic_set(&finfo->fi_mmapped, 0);
	bindex = au_dbstart(dentry);
	h_file = au_h_open(dentry, bindex, flags, file, /*force_wr*/0);
	if (IS_ERR(h_file))
		err = PTR_ERR(h_file);
	else {
		au_set_fbstart(file, bindex);
		au_set_h_fptr(file, bindex, h_file);
		au_update_figen(file);
		finfo->fi_file = file;
		au_sphl_add(&finfo->fi_hlist, &au_sbi(dentry->d_sb)->si_files);
		/* todo: necessary? */
		/* file->f_ra = h_file->f_ra; */
	}

	return err;
}

static int au_wbr_create_mfs(struct dentry *dentry, int isdir __maybe_unused)
{
	int err;
	struct super_block *sb;
	struct au_wbr_mfs *mfs;

	err = au_wbr_create_exp(dentry);
	if (err >= 0)
		goto out;

	sb = dentry->d_sb;
	mfs = &au_sbi(sb)->si_wbr_mfs;
	mutex_lock(&mfs->mfs_lock);
	if (time_after(jiffies, mfs->mfs_jiffy + mfs->mfs_expire)
	    || mfs->mfs_bindex < 0
	    || au_br_rdonly(au_sbr(sb, mfs->mfs_bindex)))
		au_mfs(dentry);
	mutex_unlock(&mfs->mfs_lock);
	err = mfs->mfs_bindex;

	if (err >= 0)
		err = au_wbr_nonopq(dentry, err);

out:
	AuDbg("b%d\n", err);
	return err;
}

void au_fhsm_wrote(struct super_block *sb, aufs_bindex_t bindex, int force)
{
	int err;
	struct au_sbinfo *sbinfo;
	struct au_fhsm *fhsm;
	struct au_branch *br;
	struct au_br_fhsm *bf;

	AuDbg("b%d, force %d\n", bindex, force);
	SiMustAnyLock(sb);

	sbinfo = au_sbi(sb);
	fhsm = &sbinfo->si_fhsm;
	if (!au_ftest_si(sbinfo, FHSM)
	    || fhsm->fhsm_bottom == bindex)
		return;

	br = au_sbr(sb, bindex);
	bf = br->br_fhsm;
	AuDebugOn(!bf);
	mutex_lock(&bf->bf_lock);
	if (force
	    || au_fhsm_pid(fhsm)
	    || au_fhsm_test_jiffy(sbinfo, br))
		err = au_fhsm_stfs(sb, bindex, /*rstfs*/NULL, /*do_lock*/0,
				  /*do_notify*/1);
	mutex_unlock(&bf->bf_lock);
}

/*
 * decide the branch and the parent dir where we will create a new entry.
 * returns new bindex or an error.
 * copyup the parent dir if needed.
 */
int au_wr_dir(struct dentry *dentry, struct dentry *src_dentry,
	      struct au_wr_dir_args *args)
{
	int err;
	aufs_bindex_t bcpup, bstart, src_bstart;
	const unsigned char add_entry = !!au_ftest_wrdir(args->flags,
							 ADD_ENTRY);
	struct super_block *sb;
	struct dentry *parent;
	struct au_sbinfo *sbinfo;

	sb = dentry->d_sb;
	sbinfo = au_sbi(sb);
	parent = dget_parent(dentry);
	bstart = au_dbstart(dentry);
	bcpup = bstart;
	if (args->force_btgt < 0) {
		if (src_dentry) {
			src_bstart = au_dbstart(src_dentry);
			if (src_bstart < bstart)
				bcpup = src_bstart;
		} else if (add_entry) {
			err = AuWbrCreate(sbinfo, dentry,
					  au_ftest_wrdir(args->flags, ISDIR));
			bcpup = err;
		}

		if (bcpup < 0 || au_test_ro(sb, bcpup, dentry->d_inode)) {
			if (add_entry)
				err = AuWbrCopyup(sbinfo, dentry);
			else {
				if (!IS_ROOT(dentry)) {
					di_read_lock_parent(parent, !AuLock_IR);
					err = AuWbrCopyup(sbinfo, dentry);
					di_read_unlock(parent, !AuLock_IR);
				} else
					err = AuWbrCopyup(sbinfo, dentry);
			}
			bcpup = err;
			if (unlikely(err < 0))
				goto out;
		}
	} else {
		bcpup = args->force_btgt;
		AuDebugOn(au_test_ro(sb, bcpup, dentry->d_inode));
	}
	AuDbg("bstart %d, bcpup %d\n", bstart, bcpup);
	err = bcpup;
	if (bcpup == bstart)
		goto out; /* success */
	else if (bstart < bcpup)
		au_update_dbrange(dentry, /*do_put_zero*/1);

	/* copyup the new parent into the branch we process */
	err = au_wr_dir_cpup(dentry, parent, add_entry, bcpup, bstart);

 out:
	dput(parent);
	return err;
}

static void au_br_do_del(struct super_block *sb, aufs_bindex_t bindex,
			 struct au_branch *br)
{
	aufs_bindex_t bend;
	struct au_sbinfo *sbinfo;
	struct dentry *root, *h_root;
	struct inode *inode, *h_inode;
	struct au_hinode *hinode;

	SiMustWriteLock(sb);

	root = sb->s_root;
	inode = root->d_inode;
	sbinfo = au_sbi(sb);
	bend = sbinfo->si_bend;

	h_root = au_h_dptr(root, bindex);
	hinode = au_hi(inode, bindex);
	h_inode = au_igrab(hinode->hi_inode);
	au_hiput(hinode);

	au_sbilist_lock();
	au_br_do_del_brp(sbinfo, bindex, bend);
	au_br_do_del_hdp(au_di(root), bindex, bend);
	au_br_do_del_hip(au_ii(inode), bindex, bend);
	au_sbilist_unlock();

	dput(h_root);
	iput(h_inode);
	au_br_do_free(br);
}

static char *au_build_path(struct dentry *h_parent, struct path *h_rootpath,
			   char *buf, int len, struct super_block *sb)
{
	char *p;
	int n;

	AuTraceEnter();

	p = d_path(h_rootpath->dentry, h_rootpath->mnt, buf, len);
	if (IS_ERR(p))
		goto out;
	n = strlen(p);

	p = d_path(h_parent, h_rootpath->mnt, buf, len);
	if (IS_ERR(p))
		goto out;
	LKTRTrace("%s\n", p);
	if (n != 1)
		p += n;
	LKTRTrace("%p, %s, %ld\n",
		  p, p, (long)(p - buf));

	p = d_path(sb->s_root, au_sbi(sb)->si_mnt, buf, len - strlen(p));
	if (IS_ERR(p))
		goto out;
	if (n != 1)
		p[strlen(p)] = '/';
	LKTRTrace("%s\n", p);

 out:
	AuTraceErrPtr(p);
	return p;
}

/* cf. aufs_rmdir() */
static int au_ren_del_whtmp(struct au_ren_args *a)
{
	int err;
	struct inode *dir;

	dir = a->dst_dir;
	SiMustAnyLock(dir->i_sb);
	if (!au_nhash_test_longer_wh(&a->whlist, a->btgt,
				     au_sbi(dir->i_sb)->si_dirwh)
	    || au_test_fs_remote(a->h_dst->d_sb)) {
		err = au_whtmp_rmdir(dir, a->btgt, a->h_dst, &a->whlist);
		if (unlikely(err))
			pr_warning("failed removing whtmp dir %.*s (%d), "
				   "ignored.\n", AuDLNPair(a->h_dst), err);
	} else {
		au_nhash_wh_free(&a->thargs->whlist);
		a->thargs->whlist = a->whlist;
		a->whlist.nh_num = 0;
		au_whtmp_kick_rmdir(dir, a->btgt, a->h_dst, a->thargs);
		dput(a->h_dst);
		a->thargs = NULL;
	}

	return 0;
}

static /* noinline_for_stack */
struct dentry *decode_by_dir_ino(struct super_block *sb, ino_t ino,
				 ino_t dir_ino, struct au_nfsd_si_lock *nsi_lock)
{
	struct dentry *dentry, *parent;
	struct path path;

	LKTRTrace("i%lu, diri%lu\n",
		  (unsigned long)ino, (unsigned long)dir_ino);

	parent = sb->s_root;
	if (dir_ino != AUFS_ROOT_INO) {
		parent = decode_by_ino(sb, dir_ino, 0);
		dentry = parent;
		if (!parent)
			goto out;
		if (IS_ERR(parent))
			goto out;
		AuDebugOn(au_test_anon(parent));
	} else
		dget(parent);

	path.dentry = parent;
	path.mnt = au_sbi(sb)->si_mnt;
	dentry = au_lkup_by_ino(&path, ino, nsi_lock);
	dput(parent);

 out:
	AuTraceErrPtr(dentry);
	return dentry;
}

static int au_wbr_create_mfs(struct dentry *dentry, unsigned int flags)
{
	int err;
	struct dentry *parent;
	struct super_block *sb;
	struct au_wbr_mfs *mfs;

	err = au_wbr_create_exp(dentry);
	if (err >= 0)
		goto out;

	sb = dentry->d_sb;
	parent = NULL;
	if (au_ftest_wbr(flags, PARENT))
		parent = dget_parent(dentry);
	mfs = &au_sbi(sb)->si_wbr_mfs;
	mutex_lock(&mfs->mfs_lock);
	if (time_after(jiffies, mfs->mfs_jiffy + mfs->mfs_expire)
	    || mfs->mfs_bindex < 0
	    || au_br_rdonly(au_sbr(sb, mfs->mfs_bindex)))
		au_mfs(dentry, parent);
	mutex_unlock(&mfs->mfs_lock);
	err = mfs->mfs_bindex;
	dput(parent);

	if (err >= 0)
		err = au_wbr_nonopq(dentry, err);

out:
	AuDbg("b%d\n", err);
	return err;
}

static void au_do_dir_ts(void *arg)
{
	struct au_dir_ts_arg *a = arg;
	struct au_dtime dt;
	struct path h_path;
	struct inode *dir, *h_dir;
	struct super_block *sb;
	struct au_branch *br;
	struct au_hinode *hdir;
	int err;
	aufs_bindex_t btop, bindex;

	sb = a->dentry->d_sb;
	if (d_really_is_negative(a->dentry))
		goto out;
	/* no dir->i_mutex lock */
	aufs_read_lock(a->dentry, AuLock_DW); /* noflush */

	dir = d_inode(a->dentry);
	btop = au_ibtop(dir);
	bindex = au_br_index(sb, a->brid);
	if (bindex < btop)
		goto out_unlock;

	br = au_sbr(sb, bindex);
	h_path.dentry = au_h_dptr(a->dentry, bindex);
	if (!h_path.dentry)
		goto out_unlock;
	h_path.mnt = au_br_mnt(br);
	au_dtime_store(&dt, a->dentry, &h_path);

	br = au_sbr(sb, btop);
	if (!au_br_writable(br->br_perm))
		goto out_unlock;
	h_path.dentry = au_h_dptr(a->dentry, btop);
	h_path.mnt = au_br_mnt(br);
	err = vfsub_mnt_want_write(h_path.mnt);
	if (err)
		goto out_unlock;
	hdir = au_hi(dir, btop);
	au_hn_inode_lock_nested(hdir, AuLsc_I_PARENT);
	h_dir = au_h_iptr(dir, btop);
	if (h_dir->i_nlink
	    && timespec_compare(&h_dir->i_mtime, &dt.dt_mtime) < 0) {
		dt.dt_h_path = h_path;
		au_dtime_revert(&dt);
	}
	au_hn_inode_unlock(hdir);
	vfsub_mnt_drop_write(h_path.mnt);
	au_cpup_attr_timesizes(dir);

out_unlock:
	aufs_read_unlock(a->dentry, AuLock_DW);
out:
	dput(a->dentry);
	au_nwt_done(&au_sbi(sb)->si_nowait);
	kfree(arg);
}

/*
 * during a user process maintains the pseudo-links,
 * prohibit adding a new plink and branch manipulation.
 */
void au_plink_maint_block(struct super_block *sb)
{
	struct au_sbinfo *sbi = au_sbi(sb);

	SiMustAnyLock(sb);

	/* gave up wake_up_bit() */
	wait_event(sbi->si_plink_wq, !sbi->si_plink_maint);
}

/*
 * during a user process maintains the pseudo-links,
 * prohibit adding a new plink and branch manipulation.
 */
void au_plink_block_maintain(struct super_block *sb)
{
	struct au_sbinfo *sbi = au_sbi(sb);

	SiMustAnyLock(sb);

	/* gave up wake_up_bit() */
	wait_event(sbi->si_plink_wq, !au_ftest_si(sbi, MAINTAIN_PLINK));
}