C++ AuDbg函数代码示例

/*
 * decide if a new whiteout for @dentry is necessary or not.
 * when it is necessary, prepare the parent dir for the upper branch whose
 * branch index is @bcpup for creation. the actual creation of the whiteout will
 * be done by caller.
 * return value:
 * 0: wh is unnecessary
 * plus: wh is necessary
 * minus: error
 */
int au_wr_dir_need_wh(struct dentry *dentry, int isdir, aufs_bindex_t *bcpup)
{
	int need_wh, err;
	aufs_bindex_t bstart;
	struct super_block *sb;

	sb = dentry->d_sb;
	bstart = au_dbstart(dentry);
	if (*bcpup < 0) {
		*bcpup = bstart;
		if (au_test_ro(sb, bstart, dentry->d_inode)) {
			err = AuWbrCopyup(au_sbi(sb), dentry);
			*bcpup = err;
			if (unlikely(err < 0))
				goto out;
		}
	} else
		AuDebugOn(bstart < *bcpup
			  || au_test_ro(sb, *bcpup, dentry->d_inode));
	AuDbg("bcpup %d, bstart %d\n", *bcpup, bstart);

	if (*bcpup != bstart) {
		err = au_cpup_dirs(dentry, *bcpup);
		if (unlikely(err))
			goto out;
		need_wh = 1;
	} else {
		aufs_bindex_t old_bend, new_bend, bdiropq = -1;

		old_bend = au_dbend(dentry);
		if (isdir) {
			bdiropq = au_dbdiropq(dentry);
			au_set_dbdiropq(dentry, -1);
		}
		need_wh = au_lkup_dentry(dentry, bstart + 1, /*type*/0,
					 /*nd*/NULL);
		err = need_wh;
		if (isdir)
			au_set_dbdiropq(dentry, bdiropq);
		if (unlikely(err < 0))
			goto out;
		new_bend = au_dbend(dentry);
		if (!need_wh && old_bend != new_bend) {
			au_set_h_dptr(dentry, new_bend, NULL);
			au_set_dbend(dentry, old_bend);
		}
	}
	AuDbg("need_wh %d\n", need_wh);
	err = need_wh;

 out:
	return err;
}

static void aufs_inotify(struct inotify_watch *watch, u32 wd __maybe_unused,
			 u32 mask, u32 cookie __maybe_unused,
			 const char *h_child_name, struct inode *h_child_inode)
{
	struct au_hnotify *hnotify;
	struct qstr h_child_qstr = {
		.name = h_child_name
	};

	/* if IN_UNMOUNT happens, there must be another bug */
	AuDebugOn(mask & IN_UNMOUNT);
	if (mask & (IN_IGNORED | IN_UNMOUNT)) {
		put_inotify_watch(watch);
		return;
	}

#ifdef AuDbgHnotify
	au_debug(1);
	if (1 || !h_child_name || strcmp(h_child_name, AUFS_XINO_FNAME)) {
		AuDbg("i%lu, wd %d, mask 0x%x %s, cookie 0x%x, hcname %s,"
		      " hi%lu\n",
		      watch->inode->i_ino, wd, mask, in_name(mask), cookie,
		      h_child_name ? h_child_name : "",
		      h_child_inode ? h_child_inode->i_ino : 0);
		WARN_ON(1);
	}
	au_debug(0);
#endif

	if (h_child_name)
		h_child_qstr.len = strlen(h_child_name);
	hnotify = container_of(watch, struct au_hnotify, hn_watch);
	au_hnotify(watch->inode, hnotify, mask, &h_child_qstr, h_child_inode);
}

static int au_conv_oflags(int flags)
{
	int mask = 0;

#ifdef CONFIG_IMA
	fmode_t fmode;

	/* mask = MAY_OPEN; */
	fmode = OPEN_FMODE(flags);
	if (fmode & FMODE_READ)
		mask |= MAY_READ;
	if ((fmode & FMODE_WRITE)
	    || (flags & O_TRUNC))
		mask |= MAY_WRITE;
	/*
	 * if (flags & O_APPEND)
	 *	mask |= MAY_APPEND;
	 */
	if (flags & vfsub_fmode_to_uint(FMODE_EXEC))
		mask |= MAY_EXEC;

	AuDbg("flags 0x%x, mask 0x%x\n", flags, mask);
#endif

	return mask;
}

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 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_dbg_verify_dinode(struct dentry *dentry, const char *func, int line)
{
	struct inode *h_inode, *inode = dentry->d_inode;
	struct dentry *h_dentry;
	aufs_bindex_t bindex, bend, bi;

	if (!inode /* || au_di(dentry)->di_lsc == AuLsc_DI_TMP */)
		return;

	bend = au_dbend(dentry);
	bi = au_ibend(inode);
	if (bi < bend)
		bend = bi;
	bindex = au_dbstart(dentry);
	bi = au_ibstart(inode);
	if (bi > bindex)
		bindex = bi;

	for (; bindex <= bend; bindex++) {
		h_dentry = au_h_dptr(dentry, bindex);
		if (!h_dentry)
			continue;
		h_inode = au_h_iptr(inode, bindex);
		if (unlikely(h_inode != h_dentry->d_inode)) {
			au_debug_on();
			AuDbg("b%d, %s:%d\n", bindex, func, line);
			AuDbgDentry(dentry);
			AuDbgInode(inode);
			au_debug_off();
			BUG();
		}
	}
}

/*
 * 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;
}

/* make sure the parent dir is fine */
static int au_mvd_args_parent(const unsigned char dmsg,
                              struct au_mvd_args *a)
{
    int err;
    aufs_bindex_t bindex;

    err = 0;
    if (unlikely(au_alive_dir(a->parent))) {
        err = -ENOENT;
        AU_MVD_PR(dmsg, "parent dir is dead\n");
        goto out;
    }

    a->bopq = au_dbdiropq(a->parent);
    bindex = au_wbr_nonopq(a->dentry, a->mvd_bdst);
    AuDbg("b%d\n", bindex);
    if (unlikely((bindex >= 0 && bindex < a->mvd_bdst)
                 || (a->bopq != -1 && a->bopq < a->mvd_bdst))) {
        err = -EINVAL;
        a->mvd_errno = EAU_MVDOWN_OPAQUE;
        AU_MVD_PR(dmsg, "ancestor is opaque b%d, b%d\n",
                  a->bopq, a->mvd_bdst);
    }

out:
    AuTraceErr(err);
    return err;
}

/*
 * initial procedure of adding a new entry.
 * prepare writable branch and the parent dir, lock it,
 * and lookup whiteout for the new entry.
 */
static struct dentry*
lock_hdir_lkup_wh(struct dentry *dentry, struct au_dtime *dt,
		  struct dentry *src_dentry, struct au_pin *pin,
		  struct au_wr_dir_args *wr_dir_args)
{
	struct dentry *wh_dentry, *h_parent;
	struct super_block *sb;
	struct au_branch *br;
	int err;
	unsigned int udba;
	aufs_bindex_t bcpup;

	AuDbg("%.*s\n", AuDLNPair(dentry));

	err = au_wr_dir(dentry, src_dentry, wr_dir_args);
	bcpup = err;
	wh_dentry = ERR_PTR(err);
	if (unlikely(err < 0))
		goto out;

	sb = dentry->d_sb;
	udba = au_opt_udba(sb);
	err = au_pin(pin, dentry, bcpup, udba,
		     AuPin_DI_LOCKED | AuPin_MNT_WRITE);
	wh_dentry = ERR_PTR(err);
	if (unlikely(err))
		goto out;

	h_parent = au_pinned_h_parent(pin);
	if (udba != AuOpt_UDBA_NONE
	    && au_dbstart(dentry) == bcpup)
		err = au_may_add(dentry, bcpup, h_parent,
				 au_ftest_wrdir(wr_dir_args->flags, ISDIR));
	else if (unlikely(dentry->d_name.len > AUFS_MAX_NAMELEN))
		err = -ENAMETOOLONG;
	wh_dentry = ERR_PTR(err);
	if (unlikely(err))
		goto out_unpin;

	br = au_sbr(sb, bcpup);
	if (dt) {
		struct path tmp = {
			.dentry	= h_parent,
			.mnt	= au_br_mnt(br)
		};
		au_dtime_store(dt, au_pinned_parent(pin), &tmp);
	}

	wh_dentry = NULL;
	if (bcpup != au_dbwh(dentry))
		goto out; /* success */

	wh_dentry = au_wh_lkup(h_parent, &dentry->d_name, br);

out_unpin:
	if (IS_ERR(wh_dentry))
		au_unpin(pin);
out:
	return wh_dentry;
}

static int noinline_for_stack
au_opts_parse_mod(struct au_opt_mod *mod, substring_t args[])
{
	int err;
	struct path path;
	char *p;

	err = -EINVAL;
	mod->path = args[0].from;
	p = strchr(mod->path, '=');
	if (unlikely(!p)) {
		pr_err("no permssion %s\n", args[0].from);
		goto out;
	}

	*p++ = 0;
	err = vfsub_kern_path(mod->path, lkup_dirflags, &path);
	if (unlikely(err)) {
		pr_err("lookup failed %s (%d)\n", mod->path, err);
		goto out;
	}

	mod->perm = br_perm_val(p);
	AuDbg("mod path %s, perm 0x%x, %s\n", mod->path, mod->perm, p);
	mod->h_root = dget(path.dentry);
	path_put(&path);

out:
	return err;
}

/*
 * the lifetime of branch is independent from the entry under sysfs.
 * sysfs handles the lifetime of the entry, and never call ->show() after it is
 * unlinked.
 */
static int sysaufs_si_br(struct seq_file *seq, struct super_block *sb,
			 aufs_bindex_t bindex)
{
	int err;
	struct path path;
	struct dentry *root;
	struct au_branch *br;
	char *perm;

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

	err = 0;
	root = sb->s_root;
	di_read_lock_parent(root, !AuLock_IR);
	br = au_sbr(sb, bindex);
	path.mnt = br->br_mnt;
	path.dentry = au_h_dptr(root, bindex);
	au_seq_path(seq, &path);
	di_read_unlock(root, !AuLock_IR);
	perm = au_optstr_br_perm(br->br_perm);
	if (perm) {
		err = seq_printf(seq, "=%s\n", perm);
		kfree(perm);
		if (err == -1)
			err = -E2BIG;
	} else
		err = -ENOMEM;
	return err;
}

static int au_do_h_d_reval(struct dentry *h_dentry, unsigned int flags,
			   struct dentry *dentry, aufs_bindex_t bindex)
{
	int err, valid;

	err = 0;
	if (!(h_dentry->d_flags & DCACHE_OP_REVALIDATE))
		goto out;

	AuDbg("b%d\n", bindex);
	/*
	 * gave up supporting LOOKUP_CREATE/OPEN for lower fs,
	 * due to whiteout and branch permission.
	 */
	flags &= ~(/*LOOKUP_PARENT |*/ LOOKUP_OPEN | LOOKUP_CREATE
		   | LOOKUP_FOLLOW | LOOKUP_EXCL);
	/* it may return tri-state */
	valid = h_dentry->d_op->d_revalidate(h_dentry, flags);

	if (unlikely(valid < 0))
		err = valid;
	else if (!valid)
		err = -EINVAL;

out:
	AuTraceErr(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);
}

static int au_rdu_verify(struct aufs_rdu *rdu)
{
	AuDbg("rdu{%llu, %p, %u | %u | %llu, %u, %u | "
	      "%llu, b%d, 0x%x, g%u}\n",
	      rdu->sz, rdu->ent.e, rdu->verify[AufsCtlRduV_SZ],
	      rdu->blk,
	      rdu->rent, rdu->shwh, rdu->full,
	      rdu->cookie.h_pos, rdu->cookie.bindex, rdu->cookie.flags,
	      rdu->cookie.generation);

	if (rdu->verify[AufsCtlRduV_SZ] == sizeof(*rdu))
		return 0;

	AuDbg("%u:%u\n",
	      rdu->verify[AufsCtlRduV_SZ], (unsigned int)sizeof(*rdu));
	return -EINVAL;
}

static int au_hfsn_handle_event(struct fsnotify_group *group,
				struct fsnotify_mark *inode_mark,
				struct fsnotify_mark *vfsmount_mark,
				struct fsnotify_event *event)
{
	int err;
	struct au_hnotify *hnotify;
	struct inode *h_dir, *h_inode;
	__u32 mask;
	struct qstr h_child_qstr = {
		.name	= event->file_name,
		.len	= event->name_len
	};

	AuDebugOn(event->data_type != FSNOTIFY_EVENT_INODE);

	err = 0;
	/* if FS_UNMOUNT happens, there must be another bug */
	mask = event->mask;
	AuDebugOn(mask & FS_UNMOUNT);
	if (mask & (FS_IN_IGNORED | FS_UNMOUNT))
		goto out;

	h_dir = event->to_tell;
	h_inode = event->inode;
#ifdef AuDbgHnotify
	au_debug(1);
	if (1 || h_child_qstr.len != sizeof(AUFS_XINO_FNAME) - 1
	    || strncmp(h_child_qstr.name, AUFS_XINO_FNAME, h_child_qstr.len)) {
		AuDbg("i%lu, mask 0x%x %s, hcname %.*s, hi%lu\n",
		      h_dir->i_ino, mask, au_hfsn_name(mask),
		      AuLNPair(&h_child_qstr), h_inode ? h_inode->i_ino : 0);
		/* WARN_ON(1); */
	}
	au_debug(0);
#endif

	AuDebugOn(!inode_mark);
	hnotify = container_of(inode_mark, struct au_hnotify, hn_mark);
	err = au_hnotify(h_dir, hnotify, mask, &h_child_qstr, h_inode);

out:
	return err;
}

/* isn't it waste to ask every registered 'group'? */
/* copied from linux/fs/notify/inotify/inotify_fsnotiry.c */
/* it should be exported to modules */
static bool au_hfsn_should_send_event(struct fsnotify_group *group,
				      struct inode *h_inode,
				      struct fsnotify_mark *inode_mark,
				      struct fsnotify_mark *vfsmount_mark,
				      __u32 mask, void *data, int data_type)
{
	mask = (mask & ~FS_EVENT_ON_CHILD);
	return inode_mark->mask & mask;
}