1 files changed, 366 insertions, 0 deletions
diff --git a/fs/aufs/branch.h b/fs/aufs/branch.h
new file mode 100644
index 000000000000..594c8bd674b2
--- /dev/null
+++ b/fs/aufs/branch.h
@@ -0,0 +1,366 @@
+/* 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/>.
+ */
+
+/*
+ * branch filesystems and xino for them
+ */
+
+#ifndef __AUFS_BRANCH_H__
+#define __AUFS_BRANCH_H__
+
+#ifdef __KERNEL__
+
+#include <linux/mount.h>
+#include "dirren.h"
+#include "dynop.h"
+#include "lcnt.h"
+#include "rwsem.h"
+#include "super.h"
+
+/* ---------------------------------------------------------------------- */
+
+/* a xino file */
+struct au_xino {
+	struct file		**xi_file;
+	unsigned int		xi_nfile;
+
+	struct {
+		spinlock_t		spin;
+		ino_t			*array;
+		int			total;
+		/* reserved for future use */
+		/* unsigned long	*bitmap; */
+		wait_queue_head_t	wqh;
+	} xi_nondir;
+
+	struct mutex		xi_mtx;	/* protects xi_file array */
+	struct hlist_bl_head	xi_writing;
+
+	atomic_t		xi_truncating;
+
+	struct kref		xi_kref;
+};
+
+/* File-based Hierarchical Storage Management */
+struct au_br_fhsm {
+#ifdef CONFIG_AUFS_FHSM
+	struct mutex		bf_lock;
+	unsigned long		bf_jiffy;
+	struct aufs_stfs	bf_stfs;
+	int			bf_readable;
+#endif
+};
+
+/* members for writable branch only */
+enum {AuBrWh_BASE, AuBrWh_PLINK, AuBrWh_ORPH, AuBrWh_Last};
+struct au_wbr {
+	struct au_rwsem		wbr_wh_rwsem;
+	struct dentry		*wbr_wh[AuBrWh_Last];
+	atomic_t		wbr_wh_running;
+#define wbr_whbase		wbr_wh[AuBrWh_BASE]	/* whiteout base */
+#define wbr_plink		wbr_wh[AuBrWh_PLINK]	/* pseudo-link dir */
+#define wbr_orph		wbr_wh[AuBrWh_ORPH]	/* dir for orphans */
+
+	/* mfs mode */
+	unsigned long long	wbr_bytes;
+};
+
+/* ext2 has 3 types of operations at least, ext3 has 4 */
+#define AuBrDynOp (AuDyLast * 4)
+
+#ifdef CONFIG_AUFS_HFSNOTIFY
+/* support for asynchronous destruction */
+struct au_br_hfsnotify {
+	struct fsnotify_group	*hfsn_group;
+};
+#endif
+
+/* sysfs entries */
+struct au_brsysfs {
+	char			name[16];
+	struct attribute	attr;
+};
+
+enum {
+	AuBrSysfs_BR,
+	AuBrSysfs_BRID,
+	AuBrSysfs_Last
+};
+
+/* protected by superblock rwsem */
+struct au_branch {
+	struct au_xino		*br_xino;
+
+	aufs_bindex_t		br_id;
+
+	int			br_perm;
+	struct path		br_path;
+	spinlock_t		br_dykey_lock;
+	struct au_dykey		*br_dykey[AuBrDynOp];
+	au_lcnt_t		br_nfiles;	/* opened files */
+	au_lcnt_t		br_count;	/* in-use for other */
+
+	struct au_wbr		*br_wbr;
+	struct au_br_fhsm	*br_fhsm;
+
+#ifdef CONFIG_AUFS_HFSNOTIFY
+	struct au_br_hfsnotify	*br_hfsn;
+#endif
+
+#ifdef CONFIG_SYSFS
+	/* entries under sysfs per mount-point */
+	struct au_brsysfs	br_sysfs[AuBrSysfs_Last];
+#endif
+
+#ifdef CONFIG_DEBUG_FS
+	struct dentry		 *br_dbgaufs; /* xino */
+#endif
+
+	struct au_dr_br		br_dirren;
+};
+
+/* ---------------------------------------------------------------------- */
+
+static inline struct vfsmount *au_br_mnt(struct au_branch *br)
+{
+	return br->br_path.mnt;
+}
+
+static inline struct dentry *au_br_dentry(struct au_branch *br)
+{
+	return br->br_path.dentry;
+}
+
+static inline struct super_block *au_br_sb(struct au_branch *br)
+{
+	return au_br_mnt(br)->mnt_sb;
+}
+
+static inline int au_br_rdonly(struct au_branch *br)
+{
+	return (sb_rdonly(au_br_sb(br))
+		|| !au_br_writable(br->br_perm))
+		? -EROFS : 0;
+}
+
+static inline int au_br_hnotifyable(int brperm __maybe_unused)
+{
+#ifdef CONFIG_AUFS_HNOTIFY
+	return !(brperm & AuBrPerm_RR);
+#else
+	return 0;
+#endif
+}
+
+static inline int au_br_test_oflag(int oflag, struct au_branch *br)
+{
+	int err, exec_flag;
+
+	err = 0;
+	exec_flag = oflag & __FMODE_EXEC;
+	if (unlikely(exec_flag && path_noexec(&br->br_path)))
+		err = -EACCES;
+
+	return err;
+}
+
+static inline void au_xino_get(struct au_branch *br)
+{
+	struct au_xino *xi;
+
+	xi = br->br_xino;
+	if (xi)
+		kref_get(&xi->xi_kref);
+}
+
+static inline int au_xino_count(struct au_branch *br)
+{
+	int v;
+	struct au_xino *xi;
+
+	v = 0;
+	xi = br->br_xino;
+	if (xi)
+		v = kref_read(&xi->xi_kref);
+
+	return v;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/* branch.c */
+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 remount);
+struct au_opt_del;
+int au_br_del(struct super_block *sb, struct au_opt_del *del, int remount);
+long au_ibusy_ioctl(struct file *file, unsigned long arg);
+#ifdef CONFIG_COMPAT
+long au_ibusy_compat_ioctl(struct file *file, unsigned long arg);
+#endif
+struct au_opt_mod;
+int au_br_mod(struct super_block *sb, struct au_opt_mod *mod, int remount,
+	      int *do_refresh);
+struct aufs_stfs;
+int au_br_stfs(struct au_branch *br, struct aufs_stfs *stfs);
+
+/* xino.c */
+static const loff_t au_loff_max = LLONG_MAX;
+
+aufs_bindex_t au_xi_root(struct super_block *sb, struct dentry *dentry);
+struct file *au_xino_create(struct super_block *sb, char *fpath, int silent,
+			    int wbrtop);
+struct file *au_xino_create2(struct super_block *sb, struct path *base,
+			     struct file *copy_src);
+struct au_xi_new {
+	struct au_xino *xi;	/* switch between xino and xigen */
+	int idx;
+	struct path *base;
+	struct file *copy_src;
+};
+struct file *au_xi_new(struct super_block *sb, struct au_xi_new *xinew);
+
+int au_xino_read(struct super_block *sb, aufs_bindex_t bindex, ino_t h_ino,
+		 ino_t *ino);
+int au_xino_write(struct super_block *sb, aufs_bindex_t bindex, ino_t h_ino,
+		  ino_t ino);
+ssize_t xino_fread(vfs_readf_t func, struct file *file, void *buf, size_t size,
+		   loff_t *pos);
+ssize_t xino_fwrite(vfs_writef_t func, struct file *file, void *buf,
+		    size_t size, loff_t *pos);
+
+int au_xib_trunc(struct super_block *sb);
+int au_xino_trunc(struct super_block *sb, aufs_bindex_t bindex, int idx_begin);
+
+struct au_xino *au_xino_alloc(unsigned int nfile);
+int au_xino_put(struct au_branch *br);
+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 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);
+
+ino_t au_xino_new_ino(struct super_block *sb);
+void au_xino_delete_inode(struct inode *inode, const int unlinked);
+
+void au_xinondir_leave(struct super_block *sb, aufs_bindex_t bindex,
+		       ino_t h_ino, int idx);
+int au_xinondir_enter(struct super_block *sb, aufs_bindex_t bindex, ino_t h_ino,
+		      int *idx);
+
+int au_xino_path(struct seq_file *seq, struct file *file);
+
+/* ---------------------------------------------------------------------- */
+
+/* @idx is signed to accept -1 meaning the first file */
+static inline struct file *au_xino_file(struct au_xino *xi, int idx)
+{
+	struct file *file;
+
+	file = NULL;
+	if (!xi)
+		goto out;
+
+	if (idx >= 0) {
+		if (idx < xi->xi_nfile)
+			file = xi->xi_file[idx];
+	} else
+		file = au_xino_file1(xi);
+
+out:
+	return file;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/* Superblock to branch */
+static inline
+aufs_bindex_t au_sbr_id(struct super_block *sb, aufs_bindex_t bindex)
+{
+	return au_sbr(sb, bindex)->br_id;
+}
+
+static inline
+struct vfsmount *au_sbr_mnt(struct super_block *sb, aufs_bindex_t bindex)
+{
+	return au_br_mnt(au_sbr(sb, bindex));
+}
+
+static inline
+struct super_block *au_sbr_sb(struct super_block *sb, aufs_bindex_t bindex)
+{
+	return au_br_sb(au_sbr(sb, bindex));
+}
+
+static inline int au_sbr_perm(struct super_block *sb, aufs_bindex_t bindex)
+{
+	return au_sbr(sb, bindex)->br_perm;
+}
+
+static inline int au_sbr_whable(struct super_block *sb, aufs_bindex_t bindex)
+{
+	return au_br_whable(au_sbr_perm(sb, bindex));
+}
+
+/* ---------------------------------------------------------------------- */
+
+#define wbr_wh_read_lock(wbr)	au_rw_read_lock(&(wbr)->wbr_wh_rwsem)
+#define wbr_wh_write_lock(wbr)	au_rw_write_lock(&(wbr)->wbr_wh_rwsem)
+#define wbr_wh_read_trylock(wbr)	au_rw_read_trylock(&(wbr)->wbr_wh_rwsem)
+#define wbr_wh_write_trylock(wbr) au_rw_write_trylock(&(wbr)->wbr_wh_rwsem)
+/*
+#define wbr_wh_read_trylock_nested(wbr) \
+	au_rw_read_trylock_nested(&(wbr)->wbr_wh_rwsem)
+#define wbr_wh_write_trylock_nested(wbr) \
+	au_rw_write_trylock_nested(&(wbr)->wbr_wh_rwsem)
+*/
+
+#define wbr_wh_read_unlock(wbr)	au_rw_read_unlock(&(wbr)->wbr_wh_rwsem)
+#define wbr_wh_write_unlock(wbr)	au_rw_write_unlock(&(wbr)->wbr_wh_rwsem)
+#define wbr_wh_downgrade_lock(wbr)	au_rw_dgrade_lock(&(wbr)->wbr_wh_rwsem)
+
+#define WbrWhMustNoWaiters(wbr)	AuRwMustNoWaiters(&(wbr)->wbr_wh_rwsem)
+#define WbrWhMustAnyLock(wbr)	AuRwMustAnyLock(&(wbr)->wbr_wh_rwsem)
+#define WbrWhMustWriteLock(wbr)	AuRwMustWriteLock(&(wbr)->wbr_wh_rwsem)
+
+/* ---------------------------------------------------------------------- */
+
+#ifdef CONFIG_AUFS_FHSM
+static inline void au_br_fhsm_init(struct au_br_fhsm *brfhsm)
+{
+	mutex_init(&brfhsm->bf_lock);
+	brfhsm->bf_jiffy = 0;
+	brfhsm->bf_readable = 0;
+}
+
+static inline void au_br_fhsm_fin(struct au_br_fhsm *brfhsm)
+{
+	mutex_destroy(&brfhsm->bf_lock);
+}
+#else
+AuStubVoid(au_br_fhsm_init, struct au_br_fhsm *brfhsm)
+AuStubVoid(au_br_fhsm_fin, struct au_br_fhsm *brfhsm)
+#endif
+
+#endif /* __KERNEL__ */
+#endif /* __AUFS_BRANCH_H__ */