aufs: branch management, delete 3/3, mount option

Implement the user interface.
Since users often wonder "Why I cannot delete this branch?", 'verbose'
option was introduced.

You may think aufs should not hold several strings for the variation of
the option, and the mount helper (/sbin/mount.aufs) can convert all
variations to a single fixed string, and in kernel space aufs should
contain this only one string.
I agree, but in our real world, many users don't install
/sbin/mount.aufs. To be convenient, aufs contains these variations.
Signed-off-by: J. R. Okajima <hooanon05g@gmail.com>

fs/aufs/branch.c

@@ -560,6 +560,12 @@ static void au_farray_free(struct file **a, unsigned long long max)
  * delete a branch
  */
 
+/* to show the line number, do not make it inlined function */
+#define AuVerbose(do_info, fmt, ...) do { \
+	if (do_info) \
+		pr_info(fmt, ##__VA_ARGS__); \
+} while (0)
+
 static int au_test_ibusy(struct inode *inode, aufs_bindex_t btop,
 			 aufs_bindex_t bbot)
 {
@@ -576,7 +582,7 @@ static int au_test_dbusy(struct dentry *dentry, aufs_bindex_t btop,
  * test if the branch is deletable or not.
  */
 static int test_dentry_busy(struct dentry *root, aufs_bindex_t bindex,
-			    unsigned int sigen)
+			    unsigned int sigen, const unsigned int verbose)
 {
 	int err, i, j, ndentry;
 	aufs_bindex_t btop, bbot;
@@ -626,6 +632,7 @@ static int test_dentry_busy(struct dentry *root, aufs_bindex_t bindex,
 			    && au_h_dptr(d, bindex)
 			    && au_test_dbusy(d, btop, bbot)) {
 				err = -EBUSY;
+				AuVerbose(verbose, "busy %pd\n", d);
 				AuDbgDentry(d);
 			}
 			di_read_unlock(d, AuLock_IR);
@@ -639,7 +646,7 @@ out:
 }
 
 static int test_inode_busy(struct super_block *sb, aufs_bindex_t bindex,
-			   unsigned int sigen)
+			   unsigned int sigen, const unsigned int verbose)
 {
 	int err;
 	unsigned long long max, ull;
@@ -682,6 +689,7 @@ static int test_inode_busy(struct super_block *sb, aufs_bindex_t bindex,
 		    && au_h_iptr(i, bindex)
 		    && au_test_ibusy(i, btop, bbot)) {
 			err = -EBUSY;
+			AuVerbose(verbose, "busy i%lu\n", i->i_ino);
 			AuDbgInode(i);
 		}
 		ii_read_unlock(i);
@@ -692,7 +700,8 @@ out:
 	return err;
 }
 
-static int test_children_busy(struct dentry *root, aufs_bindex_t bindex)
+static int test_children_busy(struct dentry *root, aufs_bindex_t bindex,
+			      const unsigned int verbose)
 {
 	int err;
 	unsigned int sigen;
@@ -701,9 +710,9 @@ static int test_children_busy(struct dentry *root, aufs_bindex_t bindex)
 	DiMustNoWaiters(root);
 	IiMustNoWaiters(d_inode(root));
 	di_write_unlock(root);
-	err = test_dentry_busy(root, bindex, sigen);
+	err = test_dentry_busy(root, bindex, sigen, verbose);
 	if (!err)
-		err = test_inode_busy(root->d_sb, bindex, sigen);
+		err = test_inode_busy(root->d_sb, bindex, sigen, verbose);
 	di_write_lock_child(root); /* aufs_write_lock() calls ..._child() */
 
 	return err;
@@ -941,7 +950,7 @@ int au_br_del(struct super_block *sb, struct au_opt_del *del, int remount)
 	unsigned long long opened;
 	unsigned int mnt_flags;
 	aufs_bindex_t bindex, bbot, br_id;
-	unsigned char do_wh;
+	unsigned char do_wh, verbose;
 	struct au_branch *br;
 	struct au_wbr *wbr;
 	struct dentry *root;
@@ -963,13 +972,19 @@ int au_br_del(struct super_block *sb, struct au_opt_del *del, int remount)
 
 	err = -EBUSY;
 	mnt_flags = au_mntflags(sb);
+	verbose = !!au_opt_test(mnt_flags, VERBOSE);
 	bbot = au_sbbot(sb);
-	if (unlikely(!bbot))
+	if (unlikely(!bbot)) {
+		AuVerbose(verbose, "no more branches left\n");
 		goto out;
+	}
+
 	br = au_sbr(sb, bindex);
 	AuDebugOn(!path_equal(&br->br_path, &del->h_path));
-	if (unlikely(au_lcnt_read(&br->br_count, /*do_rev*/1)))
+	if (unlikely(au_lcnt_read(&br->br_count, /*do_rev*/1))) {
+		AuVerbose(verbose, "br %pd2 is busy now\n", del->h_path.dentry);
 		goto out;
+	}
 
 	br_id = br->br_id;
 	opened = au_lcnt_read(&br->br_nfiles, /*do_rev*/1);
@@ -980,9 +995,11 @@ int au_br_del(struct super_block *sb, struct au_opt_del *del, int remount)
 			goto out;
 
 		err = test_file_busy(sb, br_id, to_free, opened);
-		if (unlikely(err))
+		if (unlikely(err)) {
+			AuVerbose(verbose, "%llu file(s) opened\n", opened);
 			goto out;
 		}
+	}
 
 	wbr = br->br_wbr;
 	do_wh = wbr && (wbr->wbr_whbase || wbr->wbr_plink || wbr->wbr_orph);
@@ -995,7 +1012,7 @@ int au_br_del(struct super_block *sb, struct au_opt_del *del, int remount)
 		}
 	}
 
-	err = test_children_busy(root, bindex);
+	err = test_children_busy(root, bindex, verbose);
 	if (unlikely(err)) {
 		if (do_wh)
 			goto out_wh;

fs/aufs/cpup.c

@@ -210,9 +210,7 @@ int cpup_iattr(struct dentry *dst, aufs_bindex_t bindex, struct dentry *h_src,
 	icex = br->br_perm & AuBrAttr_ICEX;
 	if (!err) {
 		mnt_flags = au_mntflags(dst->d_sb);
-		/* re-commit later */
-		/* verbose = !!au_opt_test(mnt_flags, VERBOSE); */
-		verbose = 0;
+		verbose = !!au_opt_test(mnt_flags, VERBOSE);
 		err = au_cpup_xattr(h_path.dentry, h_src, icex, verbose);
 	}
 

fs/aufs/opts.c

@@ -16,7 +16,8 @@
 
 enum {
 	Opt_br,
-	Opt_add, Opt_append, Opt_prepend,
+	Opt_add, Opt_del, Opt_append, Opt_prepend,
+	Opt_idel,
 	Opt_rdcache, Opt_rdblk, Opt_rdhash,
 	Opt_rdblk_def, Opt_rdhash_def,
 	Opt_xino, Opt_noxino,
@@ -27,6 +28,7 @@ enum {
 	Opt_udba,
 	Opt_dio, Opt_nodio,
 	Opt_wbr_copyup, Opt_wbr_create,
+	Opt_verbose, Opt_noverbose,
 	Opt_acl, Opt_noacl,
 	Opt_tail, Opt_ignore, Opt_ignore_silent, Opt_err
 };
@@ -44,6 +46,10 @@ static match_table_t options = {
 	{Opt_prepend, "prepend=%s"},
 	{Opt_prepend, "prepend:%s"},
 
+	{Opt_del, "del=%s"},
+	{Opt_del, "del:%s"},
+	/* {Opt_idel, "idel:%d"}, */
+
 	{Opt_xino, "xino=%s"},
 	{Opt_noxino, "noxino"},
 	{Opt_trunc_xino, "trunc_xino"},
@@ -72,6 +78,13 @@ static match_table_t options = {
 	{Opt_dio, "dio"},
 	{Opt_nodio, "nodio"},
 
+	{Opt_verbose, "verbose"},
+	{Opt_verbose, "v"},
+	{Opt_noverbose, "noverbose"},
+	{Opt_noverbose, "quiet"},
+	{Opt_noverbose, "q"},
+	{Opt_noverbose, "silent"},
+
 	{Opt_rdcache, "rdcache=%d"},
 	{Opt_rdblk, "rdblk=%d"},
 	{Opt_rdblk_def, "rdblk=def"},
@@ -457,6 +470,7 @@ static void dump_opts(struct au_opts *opts)
 	/* reduce stack space */
 	union {
 		struct au_opt_add *add;
+		struct au_opt_del *del;
 		struct au_opt_xino *xino;
 		struct au_opt_xino_itrunc *xino_itrunc;
 		struct au_opt_wbr_create *create;
@@ -472,6 +486,12 @@ static void dump_opts(struct au_opts *opts)
 				  u.add->bindex, u.add->pathname, u.add->perm,
 				  u.add->path.dentry);
 			break;
+		case Opt_del:
+		case Opt_idel:
+			u.del = &opt->del;
+			AuDbg("del {%s, %p}\n",
+			      u.del->pathname, u.del->h_path.dentry);
+			break;
 		case Opt_append:
 			u.add = &opt->add;
 			AuDbg("append {b%d, %s, 0x%x, %p}\n",
@@ -542,6 +562,12 @@ static void dump_opts(struct au_opts *opts)
 		case Opt_nodio:
 			AuLabel(nodio);
 			break;
+		case Opt_verbose:
+			AuLabel(verbose);
+			break;
+		case Opt_noverbose:
+			AuLabel(noverbose);
+			break;
 		case Opt_wbr_create:
 			u.create = &opt->wbr_create;
 			AuDbg("create %d, %s\n", u.create->wbr_create,
@@ -595,6 +621,10 @@ void au_opts_free(struct au_opts *opts)
 		case Opt_prepend:
 			path_put(&opt->add.path);
 			break;
+		case Opt_del:
+		case Opt_idel:
+			path_put(&opt->del.h_path);
+			break;
 		case Opt_xino:
 			fput(opt->xino.file);
 			break;
@@ -639,6 +669,45 @@ out:
 	return err;
 }
 
+static int au_opts_parse_del(struct au_opt_del *del, substring_t args[])
+{
+	int err;
+
+	del->pathname = args[0].from;
+	AuDbg("del path %s\n", del->pathname);
+
+	err = vfsub_kern_path(del->pathname, lkup_dirflags, &del->h_path);
+	if (unlikely(err))
+		pr_err("lookup failed %s (%d)\n", del->pathname, err);
+
+	return err;
+}
+
+#if 0 /* reserved for future use */
+static int au_opts_parse_idel(struct super_block *sb, aufs_bindex_t bindex,
+			      struct au_opt_del *del, substring_t args[])
+{
+	int err;
+	struct dentry *root;
+
+	err = -EINVAL;
+	root = sb->s_root;
+	aufs_read_lock(root, AuLock_FLUSH);
+	if (bindex < 0 || au_sbbot(sb) < bindex) {
+		pr_err("out of bounds, %d\n", bindex);
+		goto out;
+	}
+
+	err = 0;
+	del->h_path.dentry = dget(au_h_dptr(root, bindex));
+	del->h_path.mnt = mntget(au_sbr_mnt(sb, bindex));
+
+out:
+	aufs_read_unlock(root, !AuLock_IR);
+	return err;
+}
+#endif
+
 static int au_opts_parse_xino(struct super_block *sb, struct au_opt_xino *xino,
 			      substring_t args[])
 {
@@ -774,7 +843,23 @@ int au_opts_parse(struct super_block *sb, char *str, struct au_opts *opts)
 			if (!err)
 				opt->type = token;
 			break;
-
+		case Opt_del:
+			err = au_opts_parse_del(&opt->del, a->args);
+			if (!err)
+				opt->type = token;
+			break;
+#if 0 /* reserved for future use */
+		case Opt_idel:
+			del->pathname = "(indexed)";
+			if (unlikely(match_int(&args[0], &n))) {
+				pr_err("bad integer in %s\n", opt_str);
+				break;
+			}
+			err = au_opts_parse_idel(sb, n, &opt->del, a->args);
+			if (!err)
+				opt->type = token;
+			break;
+#endif
 		case Opt_xino:
 			err = au_opts_parse_xino(sb, &opt->xino, a->args);
 			if (!err)
@@ -859,6 +944,8 @@ int au_opts_parse(struct super_block *sb, char *str, struct au_opts *opts)
 		case Opt_list_plink:
 		case Opt_dio:
 		case Opt_nodio:
+		case Opt_verbose:
+		case Opt_noverbose:
 		case Opt_rdblk_def:
 		case Opt_rdhash_def:
 		case Opt_acl:
@@ -1013,6 +1100,13 @@ static int au_opt_simple(struct super_block *sb, struct au_opt *opt,
 		au_fset_opts(opts->flags, REFRESH_DYAOP);
 		break;
 
+	case Opt_verbose:
+		au_opt_set(sbinfo->si_mntflags, VERBOSE);
+		break;
+	case Opt_noverbose:
+		au_opt_clr(sbinfo->si_mntflags, VERBOSE);
+		break;
+
 	case Opt_wbr_create:
 		err = au_opt_wbr_create(sb, &opt->wbr_create);
 		break;
@@ -1104,6 +1198,17 @@ static int au_opt_br(struct super_block *sb, struct au_opt *opt,
 			au_fset_opts(opts->flags, REFRESH);
 		}
 		break;
+
+	case Opt_del:
+	case Opt_idel:
+		err = au_br_del(sb, &opt->del,
+				au_ftest_opts(opts->flags, REMOUNT));
+		if (!err) {
+			err = 1;
+			au_fset_opts(opts->flags, TRUNC_XIB);
+			au_fset_opts(opts->flags, REFRESH);
+		}
+		break;
 	}
 	return err;
 }

fs/aufs/opts.h

@@ -26,6 +26,7 @@ struct file;
 #define AuOpt_UDBA_REVAL	(1 << 3)
 #define AuOpt_UDBA_HNOTIFY	(1 << 4)
 #define AuOpt_PLINK		(1 << 6)	/* pseudo-link */
+#define AuOpt_VERBOSE		(1 << 13)	/* print the cause of error */
 #define AuOpt_DIO		(1 << 14)	/* direct io */
 
 #ifndef CONFIG_AUFS_HNOTIFY
@@ -125,6 +126,7 @@ struct au_opt {
 		struct au_opt_xino	xino;
 		struct au_opt_xino_itrunc xino_itrunc;
 		struct au_opt_add	add;
+		struct au_opt_del	del;
 		int			rdcache;
 		unsigned int		rdblk;
 		unsigned int		rdhash;

fs/aufs/super.c

@@ -273,6 +273,8 @@ static int aufs_show_options(struct seq_file *m, struct dentry *dentry)
 	AuUInt(RDBLK, rdblk, sbinfo->si_rdblk);
 	AuUInt(RDHASH, rdhash, sbinfo->si_rdhash);
 
+	AuBool(VERBOSE, verbose);
+
 out:
 	/* be sure to print "br:" last */
 	if (!sysaufs_brs) {