1 files changed, 288 insertions, 0 deletions
diff --git a/fs/aufs/hfsnotify.c b/fs/aufs/hfsnotify.c
new file mode 100644
index 000000000000..cb4eeb1e6069
--- /dev/null
+++ b/fs/aufs/hfsnotify.c
@@ -0,0 +1,288 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2005-2020 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 <http://www.gnu.org/licenses/>.
+ */
+
+/*
+ * fsnotify for the lower directories
+ */
+
+#include "aufs.h"
+
+/* FS_IN_IGNORED is unnecessary */
+static const __u32 AuHfsnMask = (FS_MOVED_TO | FS_MOVED_FROM | FS_DELETE
+				 | FS_CREATE | FS_EVENT_ON_CHILD);
+static DECLARE_WAIT_QUEUE_HEAD(au_hfsn_wq);
+static __cacheline_aligned_in_smp atomic64_t au_hfsn_ifree = ATOMIC64_INIT(0);
+
+static void au_hfsn_free_mark(struct fsnotify_mark *mark)
+{
+	struct au_hnotify *hn = container_of(mark, struct au_hnotify,
+					     hn_mark);
+	/* AuDbg("here\n"); */
+	au_cache_free_hnotify(hn);
+	smp_mb__before_atomic(); /* for atomic64_dec */
+	if (atomic64_dec_and_test(&au_hfsn_ifree))
+		wake_up(&au_hfsn_wq);
+}
+
+static int au_hfsn_alloc(struct au_hinode *hinode)
+{
+	int err;
+	struct au_hnotify *hn;
+	struct super_block *sb;
+	struct au_branch *br;
+	struct fsnotify_mark *mark;
+	aufs_bindex_t bindex;
+
+	hn = hinode->hi_notify;
+	sb = hn->hn_aufs_inode->i_sb;
+	bindex = au_br_index(sb, hinode->hi_id);
+	br = au_sbr(sb, bindex);
+	AuDebugOn(!br->br_hfsn);
+
+	mark = &hn->hn_mark;
+	fsnotify_init_mark(mark, br->br_hfsn->hfsn_group);
+	mark->mask = AuHfsnMask;
+	/*
+	 * by udba rename or rmdir, aufs assign a new inode to the known
+	 * h_inode, so specify 1 to allow dups.
+	 */
+	lockdep_off();
+	err = fsnotify_add_inode_mark(mark, hinode->hi_inode, /*allow_dups*/1);
+	lockdep_on();
+
+	return err;
+}
+
+static int au_hfsn_free(struct au_hinode *hinode, struct au_hnotify *hn)
+{
+	struct fsnotify_mark *mark;
+	unsigned long long ull;
+	struct fsnotify_group *group;
+
+	ull = atomic64_inc_return(&au_hfsn_ifree);
+	BUG_ON(!ull);
+
+	mark = &hn->hn_mark;
+	spin_lock(&mark->lock);
+	group = mark->group;
+	fsnotify_get_group(group);
+	spin_unlock(&mark->lock);
+	lockdep_off();
+	fsnotify_destroy_mark(mark, group);
+	fsnotify_put_mark(mark);
+	fsnotify_put_group(group);
+	lockdep_on();
+
+	/* free hn by myself */
+	return 0;
+}
+
+/* ---------------------------------------------------------------------- */
+
+static void au_hfsn_ctl(struct au_hinode *hinode, int do_set)
+{
+	struct fsnotify_mark *mark;
+
+	mark = &hinode->hi_notify->hn_mark;
+	spin_lock(&mark->lock);
+	if (do_set) {
+		AuDebugOn(mark->mask & AuHfsnMask);
+		mark->mask |= AuHfsnMask;
+	} else {
+		AuDebugOn(!(mark->mask & AuHfsnMask));
+		mark->mask &= ~AuHfsnMask;
+	}
+	spin_unlock(&mark->lock);
+	/* fsnotify_recalc_inode_mask(hinode->hi_inode); */
+}
+
+/* ---------------------------------------------------------------------- */
+
+/* #define AuDbgHnotify */
+#ifdef AuDbgHnotify
+static char *au_hfsn_name(u32 mask)
+{
+#ifdef CONFIG_AUFS_DEBUG
+#define test_ret(flag)				\
+	do {					\
+		if (mask & flag)		\
+			return #flag;		\
+	} while (0)
+	test_ret(FS_ACCESS);
+	test_ret(FS_MODIFY);
+	test_ret(FS_ATTRIB);
+	test_ret(FS_CLOSE_WRITE);
+	test_ret(FS_CLOSE_NOWRITE);
+	test_ret(FS_OPEN);
+	test_ret(FS_MOVED_FROM);
+	test_ret(FS_MOVED_TO);
+	test_ret(FS_CREATE);
+	test_ret(FS_DELETE);
+	test_ret(FS_DELETE_SELF);
+	test_ret(FS_MOVE_SELF);
+	test_ret(FS_UNMOUNT);
+	test_ret(FS_Q_OVERFLOW);
+	test_ret(FS_IN_IGNORED);
+	test_ret(FS_ISDIR);
+	test_ret(FS_IN_ONESHOT);
+	test_ret(FS_EVENT_ON_CHILD);
+	return "";
+#undef test_ret
+#else
+	return "??";
+#endif
+}
+#endif
+
+/* ---------------------------------------------------------------------- */
+
+static void au_hfsn_free_group(struct fsnotify_group *group)
+{
+	struct au_br_hfsnotify *hfsn = group->private;
+
+	/* AuDbg("here\n"); */
+	au_kfree_try_rcu(hfsn);
+}
+
+static int au_hfsn_handle_event(struct fsnotify_group *group,
+				struct inode *inode,
+				u32 mask, const void *data, int data_type,
+				const struct qstr *file_name, u32 cookie,
+				struct fsnotify_iter_info *iter_info)
+{
+	int err;
+	struct au_hnotify *hnotify;
+	struct inode *h_dir, *h_inode;
+	struct fsnotify_mark *inode_mark;
+
+	AuDebugOn(data_type != FSNOTIFY_EVENT_INODE);
+
+	err = 0;
+	/* if FS_UNMOUNT happens, there must be another bug */
+	AuDebugOn(mask & FS_UNMOUNT);
+	if (mask & (FS_IN_IGNORED | FS_UNMOUNT))
+		goto out;
+
+	h_dir = inode;
+	h_inode = NULL;
+#ifdef AuDbgHnotify
+	au_debug_on();
+	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_off();
+#endif
+
+	inode_mark = fsnotify_iter_inode_mark(iter_info);
+	AuDebugOn(!inode_mark);
+	hnotify = container_of(inode_mark, struct au_hnotify, hn_mark);
+	err = au_hnotify(h_dir, hnotify, mask, file_name, h_inode);
+
+out:
+	return err;
+}
+
+static struct fsnotify_ops au_hfsn_ops = {
+	.handle_event		= au_hfsn_handle_event,
+	.free_group_priv	= au_hfsn_free_group,
+	.free_mark		= au_hfsn_free_mark
+};
+
+/* ---------------------------------------------------------------------- */
+
+static void au_hfsn_fin_br(struct au_branch *br)
+{
+	struct au_br_hfsnotify *hfsn;
+
+	hfsn = br->br_hfsn;
+	if (hfsn) {
+		lockdep_off();
+		fsnotify_put_group(hfsn->hfsn_group);
+		lockdep_on();
+	}
+}
+
+static int au_hfsn_init_br(struct au_branch *br, int perm)
+{
+	int err;
+	struct fsnotify_group *group;
+	struct au_br_hfsnotify *hfsn;
+
+	err = 0;
+	br->br_hfsn = NULL;
+	if (!au_br_hnotifyable(perm))
+		goto out;
+
+	err = -ENOMEM;
+	hfsn = kmalloc(sizeof(*hfsn), GFP_NOFS);
+	if (unlikely(!hfsn))
+		goto out;
+
+	err = 0;
+	group = fsnotify_alloc_group(&au_hfsn_ops);
+	if (IS_ERR(group)) {
+		err = PTR_ERR(group);
+		pr_err("fsnotify_alloc_group() failed, %d\n", err);
+		goto out_hfsn;
+	}
+
+	group->private = hfsn;
+	hfsn->hfsn_group = group;
+	br->br_hfsn = hfsn;
+	goto out; /* success */
+
+out_hfsn:
+	au_kfree_try_rcu(hfsn);
+out:
+	return err;
+}
+
+static int au_hfsn_reset_br(unsigned int udba, struct au_branch *br, int perm)
+{
+	int err;
+
+	err = 0;
+	if (!br->br_hfsn)
+		err = au_hfsn_init_br(br, perm);
+
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+static void au_hfsn_fin(void)
+{
+	AuDbg("au_hfsn_ifree %lld\n", (long long)atomic64_read(&au_hfsn_ifree));
+	wait_event(au_hfsn_wq, !atomic64_read(&au_hfsn_ifree));
+}
+
+const struct au_hnotify_op au_hnotify_op = {
+	.ctl		= au_hfsn_ctl,
+	.alloc		= au_hfsn_alloc,
+	.free		= au_hfsn_free,
+
+	.fin		= au_hfsn_fin,
+
+	.reset_br	= au_hfsn_reset_br,
+	.fin_br		= au_hfsn_fin_br,
+	.init_br	= au_hfsn_init_br
+};