aufs: remount 4/5, refresh the internal branch array

Maintain the internal array including corresponding XINO file and sysfs
entries.
Signed-off-by: J. R. Okajima <hooanon05g@gmail.com>

fs/aufs/branch.c

@@ -181,7 +181,7 @@ out:
  * plus: success, it is already unified, the caller should ignore it
  * minus: error
  */
-static int test_add(struct super_block *sb, struct au_opt_add *add)
+static int test_add(struct super_block *sb, struct au_opt_add *add, int remount)
 {
 	int err;
 	aufs_bindex_t bbot, bindex;
@@ -192,8 +192,11 @@ static int test_add(struct super_block *sb, struct au_opt_add *add)
 	bbot = au_sbbot(sb);
 	if (unlikely(bbot >= 0
 		     && au_find_dbindex(root, add->path.dentry) >= 0)) {
-		err = -EINVAL;
-		pr_err("%s duplicated\n", add->pathname);
+		err = 1;
+		if (!remount) {
+			err = -EINVAL;
+			pr_err("%s duplicated\n", add->pathname);
+		}
 		goto out;
 	}
 
@@ -452,7 +455,7 @@ static void au_br_do_add(struct super_block *sb, struct au_branch *br,
 	au_set_h_iptr(root_inode, bindex, au_igrab(h_inode), /*flags*/0);
 }
 
-int au_br_add(struct super_block *sb, struct au_opt_add *add)
+int au_br_add(struct super_block *sb, struct au_opt_add *add, int remount)
 {
 	int err;
 	aufs_bindex_t bbot, add_bindex;
@@ -464,7 +467,7 @@ int au_br_add(struct super_block *sb, struct au_opt_add *add)
 	root_inode = d_inode(root);
 	IMustLock(root_inode);
 	IiMustWriteLock(root_inode);
-	err = test_add(sb, add);
+	err = test_add(sb, add, remount);
 	if (unlikely(err < 0))
 		goto out;
 	if (err) {
@@ -485,7 +488,9 @@ int au_br_add(struct super_block *sb, struct au_opt_add *add)
 	}
 
 	add_bindex = add->bindex;
+	sysaufs_brs_del(sb, add_bindex);	/* remove successors */
 	au_br_do_add(sb, add_branch, add_bindex);
+	sysaufs_brs_add(sb, add_bindex);	/* append successors */
 
 	h_dentry = add->path.dentry;
 	if (!add_bindex) {

fs/aufs/branch.h

@@ -177,7 +177,7 @@ struct au_sbinfo;
 void au_br_free(struct au_sbinfo *sinfo);
 int au_br_index(struct super_block *sb, aufs_bindex_t br_id);
 struct au_opt_add;
-int au_br_add(struct super_block *sb, struct au_opt_add *add);
+int au_br_add(struct super_block *sb, struct au_opt_add *add, int remount);
 
 /* xino.c */
 static const loff_t au_loff_max = LLONG_MAX;
@@ -212,7 +212,7 @@ struct file *au_xino_file1(struct au_xino *xi);
 
 struct au_opt_xino;
 void au_xino_clr(struct super_block *sb);
-int au_xino_set(struct super_block *sb, struct au_opt_xino *xiopt);
+int au_xino_set(struct super_block *sb, struct au_opt_xino *xiopt, int remount);
 struct file *au_xino_def(struct super_block *sb);
 int au_xino_init_br(struct super_block *sb, struct au_branch *br, ino_t hino,
 		    struct path *base);

fs/aufs/dcsub.h

@@ -40,6 +40,12 @@ int au_test_subdir(struct dentry *d1, struct dentry *d2);
 
 /* ---------------------------------------------------------------------- */
 
+static inline int au_qstreq(struct qstr *a, struct qstr *b)
+{
+	return a->len == b->len
+		&& !memcmp(a->name, b->name, a->len);
+}
+
 /*
  * by the commit
  * 360f547 2015-01-25 dcache: let the dentry count go down to zero without

fs/aufs/opts.c

@@ -1020,10 +1020,11 @@ static int au_opt_br(struct super_block *sb, struct au_opt *opt,
 	err = 0;
 	switch (opt->type) {
 	case Opt_add:
-		err = au_br_add(sb, &opt->add);
+		err = au_br_add(sb, &opt->add,
+				au_ftest_opts(opts->flags, REMOUNT));
 		if (!err) {
 			err = 1;
-			/* au_fset_opts(opts->flags, REFRESH); re-commit later */
+			au_fset_opts(opts->flags, REFRESH);
 		}
 		break;
 	}
@@ -1039,7 +1040,8 @@ static int au_opt_xino(struct super_block *sb, struct au_opt *opt,
 	err = 0;
 	switch (opt->type) {
 	case Opt_xino:
-		err = au_xino_set(sb, &opt->xino);
+		err = au_xino_set(sb, &opt->xino,
+				  !!au_ftest_opts(opts->flags, REMOUNT));
 		if (unlikely(err))
 			break;
 
@@ -1205,7 +1207,7 @@ int au_opts_mount(struct super_block *sb, struct au_opts *opts)
 		if (IS_ERR(xino.file))
 			goto out;
 
-		err = au_xino_set(sb, &xino);
+		err = au_xino_set(sb, &xino, /*remount*/0);
 		fput(xino.file);
 		if (unlikely(err))
 			goto out;
@@ -1233,6 +1235,54 @@ out:
 	return err;
 }
 
+int au_opts_remount(struct super_block *sb, struct au_opts *opts)
+{
+	int err, rerr;
+	struct inode *dir;
+	struct au_opt_xino *opt_xino;
+	struct au_opt *opt;
+	struct au_sbinfo *sbinfo;
+
+	SiMustWriteLock(sb);
+
+	err = 0;
+	dir = d_inode(sb->s_root);
+	sbinfo = au_sbi(sb);
+	opt_xino = NULL;
+	opt = opts->opt;
+	while (err >= 0 && opt->type != Opt_tail) {
+		err = au_opt_simple(sb, opt, opts);
+		if (!err)
+			err = au_opt_br(sb, opt, opts);
+		if (!err)
+			err = au_opt_xino(sb, opt, &opt_xino, opts);
+		opt++;
+	}
+	if (err > 0)
+		err = 0;
+	AuTraceErr(err);
+	/* go on even err */
+
+	rerr = au_opts_verify(sb, opts->sb_flags, /*pending*/0);
+	if (unlikely(rerr && !err))
+		err = rerr;
+
+	if (au_ftest_opts(opts->flags, TRUNC_XIB)) {
+		rerr = au_xib_trunc(sb);
+		if (unlikely(rerr && !err))
+			err = rerr;
+	}
+
+	/* will be handled by the caller */
+	if (!au_ftest_opts(opts->flags, REFRESH)
+	    && (opts->given_udba || au_opt_test(sbinfo->si_mntflags, XINO)))
+		au_fset_opts(opts->flags, REFRESH);
+
+	AuDbg("status 0x%x\n", opts->flags);
+
+	return err;
+}
+
 /* ---------------------------------------------------------------------- */
 
 unsigned int au_opt_udba(struct super_block *sb)

fs/aufs/opts.h

@@ -131,6 +131,8 @@ struct au_opt {
 };
 
 /* opts flags */
+#define AuOpts_REMOUNT		1
+#define AuOpts_REFRESH		(1 << 1)
 #define AuOpts_TRUNC_XIB	(1 << 2)
 #define AuOpts_REFRESH_DYAOP	(1 << 3)
 #define au_ftest_opts(flags, name)	((flags) & AuOpts_##name)
@@ -162,6 +164,7 @@ int au_opts_parse(struct super_block *sb, char *str, struct au_opts *opts);
 int au_opts_verify(struct super_block *sb, unsigned long sb_flags,
 		   unsigned int pending);
 int au_opts_mount(struct super_block *sb, struct au_opts *opts);
+int au_opts_remount(struct super_block *sb, struct au_opts *opts);
 
 unsigned int au_opt_udba(struct super_block *sb);
 

fs/aufs/sysaufs.h

@@ -60,6 +60,7 @@ ssize_t sysaufs_si_show(struct kobject *kobj, struct attribute *attr,
 
 void sysaufs_br_init(struct au_branch *br);
 void sysaufs_brs_add(struct super_block *sb, aufs_bindex_t bindex);
+void sysaufs_brs_del(struct super_block *sb, aufs_bindex_t bindex);
 
 #define sysaufs_brs_init()	do {} while (0)
 
@@ -71,6 +72,7 @@ AuStub(ssize_t, sysaufs_si_show, return 0, struct kobject *kobj,
        struct attribute *attr, char *buf)
 AuStubVoid(sysaufs_br_init, struct au_branch *br)
 AuStubVoid(sysaufs_brs_add, struct super_block *sb, aufs_bindex_t bindex)
+AuStubVoid(sysaufs_brs_del, struct super_block *sb, aufs_bindex_t bindex)
 
 static inline void sysaufs_brs_init(void)
 {

fs/aufs/sysfs.c

@@ -198,6 +198,29 @@ void sysaufs_br_init(struct au_branch *br)
 	}
 }
 
+void sysaufs_brs_del(struct super_block *sb, aufs_bindex_t bindex)
+{
+	struct au_branch *br;
+	struct kobject *kobj;
+	struct au_brsysfs *br_sysfs;
+	int i;
+	aufs_bindex_t bbot;
+
+	if (!sysaufs_brs)
+		return;
+
+	kobj = &au_sbi(sb)->si_kobj;
+	bbot = au_sbbot(sb);
+	for (; bindex <= bbot; bindex++) {
+		br = au_sbr(sb, bindex);
+		br_sysfs = br->br_sysfs;
+		for (i = 0; i < ARRAY_SIZE(br->br_sysfs); i++) {
+			sysfs_remove_file(kobj, &br_sysfs->attr);
+			br_sysfs++;
+		}
+	}
+}
+
 void sysaufs_brs_add(struct super_block *sb, aufs_bindex_t bindex)
 {
 	int err, i;

fs/aufs/xino.c

@@ -1564,12 +1564,14 @@ void au_xino_clr(struct super_block *sb)
 	au_opt_clr(sbinfo->si_mntflags, XINO);
 }
 
-int au_xino_set(struct super_block *sb, struct au_opt_xino *xiopt)
+int au_xino_set(struct super_block *sb, struct au_opt_xino *xiopt, int remount)
 {
-	int err;
-	struct dentry *dentry, *parent;
+	int err, skip;
+	struct dentry *dentry, *parent, *cur_dentry, *cur_parent;
+	struct qstr *dname, *cur_name;
+	struct file *cur_xino;
 	struct au_sbinfo *sbinfo;
-	struct path *path;
+	struct path *path, *cur_path;
 
 	SiMustWriteLock(sb);
 
@@ -1578,6 +1580,23 @@ int au_xino_set(struct super_block *sb, struct au_opt_xino *xiopt)
 	path = &xiopt->file->f_path;
 	dentry = path->dentry;
 	parent = dget_parent(dentry);
+	if (remount) {
+		skip = 0;
+		cur_xino = sbinfo->si_xib;
+		if (cur_xino) {
+			cur_path = &cur_xino->f_path;
+			cur_dentry = cur_path->dentry;
+			cur_parent = dget_parent(cur_dentry);
+			cur_name = &cur_dentry->d_name;
+			dname = &dentry->d_name;
+			skip = (cur_parent == parent
+				&& au_qstreq(dname, cur_name));
+			dput(cur_parent);
+		}
+		if (skip)
+			goto out;
+	}
+
 	au_opt_set(sbinfo->si_mntflags, XINO);
 	err = au_xino_set_xib(sb, path);
 	/* si_x{read,write} are set */