Merge branch 'for-next/fs-dentry-cache'

7 files changed, 279 insertions, 59 deletions

diff --git a/include/dirent.h b/include/dirent.h
index 5ee4c2063e..1df5d90452 100644
--- a/include/dirent.h
+++ b/include/dirent.h
@@ -1,6 +1,8 @@
 #ifndef __DIRENT_H
 #define __DIRENT_H
 
+#include <linux/list.h>
+
 struct dirent {
 	char d_name[256];
 };
@@ -11,6 +13,7 @@ typedef struct dir {
 	struct node_d *node;
 	struct dirent d;
 	void *priv; /* private data for the fs driver */
+	struct list_head entries;
 } DIR;
 
 DIR *opendir(const char *pathname);
diff --git a/include/fs.h b/include/fs.h
index e6fcd044dd..181318f404 100644
--- a/include/fs.h
+++ b/include/fs.h
@@ -31,14 +31,15 @@ typedef struct filep {
 	/* private fields. Mapping between FILE and filedescriptor number     */
 	int no;
 	char in_use;
+
+	struct inode *f_inode;
+	struct dentry *dentry;
 } FILE;
 
 #define FS_DRIVER_NO_DEV	1
 
 struct fs_driver_d {
 	int (*probe) (struct device_d *dev);
-	int (*mkdir)(struct device_d *dev, const char *pathname);
-	int (*rmdir)(struct device_d *dev, const char *pathname);
 
 	/* create a file. The file is guaranteed to not exist */
 	int (*create)(struct device_d *dev, const char *pathname, mode_t mode);
@@ -47,11 +48,6 @@ struct fs_driver_d {
 	/* Truncate a file to given size */
 	int (*truncate)(struct device_d *dev, FILE *f, ulong size);
 
-	int (*symlink)(struct device_d *dev, const char *pathname,
-		       const char *newpath);
-	int (*readlink)(struct device_d *dev, const char *pathname, char *name,
-			size_t size);
-
 	int (*open)(struct device_d *dev, FILE *f, const char *pathname);
 	int (*close)(struct device_d *dev, FILE *f);
 	int (*read)(struct device_d *dev, FILE *f, void *buf, size_t size);
@@ -59,11 +55,6 @@ struct fs_driver_d {
 	int (*flush)(struct device_d *dev, FILE *f);
 	loff_t (*lseek)(struct device_d *dev, FILE *f, loff_t pos);
 
-	struct dir* (*opendir)(struct device_d *dev, const char *pathname);
-	struct dirent* (*readdir)(struct device_d *dev, struct dir *dir);
-	int (*closedir)(struct device_d *dev, DIR *dir);
-	int (*stat)(struct device_d *dev, const char *file, struct stat *stat);
-
 	int (*ioctl)(struct device_d *dev, FILE *f, int request, void *buf);
 	int (*erase)(struct device_d *dev, FILE *f, loff_t count,
 			loff_t offset);
@@ -72,6 +63,18 @@ struct fs_driver_d {
 
 	int (*memmap)(struct device_d *dev, FILE *f, void **map, int flags);
 
+	/* legacy */
+	int (*mkdir)(struct device_d *dev, const char *pathname);
+	int (*rmdir)(struct device_d *dev, const char *pathname);
+	int (*symlink)(struct device_d *dev, const char *pathname,
+		       const char *newpath);
+	int (*readlink)(struct device_d *dev, const char *pathname, char *name,
+			size_t size);
+	struct dir* (*opendir)(struct device_d *dev, const char *pathname);
+	struct dirent* (*readdir)(struct device_d *dev, struct dir *dir);
+	int (*closedir)(struct device_d *dev, DIR *dir);
+	int (*stat)(struct device_d *dev, const char *file, struct stat *stat);
+
 	struct driver_d drv;
 
 	enum filetype type;
@@ -99,6 +102,10 @@ struct fs_device_d {
 	struct list_head list;
 	char *options;
 	char *linux_rootarg;
+
+	struct super_block sb;
+
+	struct vfsmount vfsmount;
 };
 
 bool __is_tftp_fs(const char *path);
@@ -135,12 +142,6 @@ int ls(const char *path, ulong flags);
 
 char *mkmodestr(unsigned long mode, char *str);
 
-/*
- * This function turns 'path' into an absolute path and removes all occurrences
- * of "..", "." and double slashes. The returned string must be freed wit free().
- */
-char *normalise_path(const char *path);
-
 char *canonicalize_path(const char *pathname);
 
 char *get_mounted_path(const char *path);
@@ -154,6 +155,7 @@ void automount_remove(const char *_path);
 int automount_add(const char *path, const char *cmd);
 void automount_print(void);
 
+int fs_init_legacy(struct fs_device_d *fsdev);
 int fsdev_open_cdev(struct fs_device_d *fsdev);
 const char *cdev_get_mount_path(struct cdev *cdev);
 const char *cdev_mount_default(struct cdev *cdev, const char *fsoptions);
diff --git a/include/linux/dcache.h b/include/linux/dcache.h
index dfb466722c..16244129bf 100644
--- a/include/linux/dcache.h
+++ b/include/linux/dcache.h
@@ -53,6 +53,10 @@ struct dentry {
 	spinlock_t d_lock;		/* per dentry lock */
 	struct inode *d_inode;		/* Where the name belongs to - NULL is
 					 * negative */
+
+	unsigned int d_count;
+	const struct dentry_operations *d_op;
+
 	/*
 	 * The next three fields are touched by __d_lookup.  Place them here
 	 * so they all fit in a cache line.
@@ -65,8 +69,8 @@ struct dentry {
 	/*
 	 * d_child and d_rcu can share memory
 	 */
+	struct list_head d_child;       /* child of parent list */
 	struct list_head d_subdirs;	/* our children */
-	struct list_head d_alias;	/* inode alias list */
 	unsigned long d_time;		/* used by d_revalidate */
 	struct super_block *d_sb;	/* The root of the dentry tree */
 	void *d_fsdata;			/* fs-specific data */
@@ -74,7 +78,108 @@ struct dentry {
 	struct dcookie_struct *d_cookie; /* cookie, if any */
 #endif
 	int d_mounted;
-	unsigned char d_iname[DNAME_INLINE_LEN_MIN];	/* small names */
+	unsigned char *name;		/* all names */
+};
+
+struct dentry_operations {
 };
 
+struct dentry * d_make_root(struct inode *);
+void d_add(struct dentry *, struct inode *);
+struct dentry * d_alloc_anon(struct super_block *);
+void d_set_d_op(struct dentry *dentry, const struct dentry_operations *op);
+void d_instantiate(struct dentry *dentry, struct inode *inode);
+void d_delete(struct dentry *);
+struct dentry *dget(struct dentry *);
+void dput(struct dentry *);
+
+#define DCACHE_ENTRY_TYPE		0x00700000
+#define DCACHE_MISS_TYPE		0x00000000 /* Negative dentry (maybe fallthru to nowhere) */
+#define DCACHE_WHITEOUT_TYPE		0x00100000 /* Whiteout dentry (stop pathwalk) */
+#define DCACHE_DIRECTORY_TYPE		0x00200000 /* Normal directory */
+#define DCACHE_AUTODIR_TYPE		0x00300000 /* Lookupless directory (presumed automount) */
+#define DCACHE_REGULAR_TYPE		0x00400000 /* Regular file type (or fallthru to such) */
+#define DCACHE_SPECIAL_TYPE		0x00500000 /* Other file type (or fallthru to such) */
+#define DCACHE_SYMLINK_TYPE		0x00600000 /* Symlink (or fallthru to such) */
+
+#define DCACHE_FALLTHRU			0x01000000 /* Fall through to lower layer */
+#define DCACHE_CANT_MOUNT		0x00000100
+#define DCACHE_MOUNTED                  0x00010000 /* is a mountpoint */
+#define DCACHE_NEED_AUTOMOUNT           0x00020000 /* handle automount on this dir */
+#define DCACHE_MANAGED_DENTRY \
+		(DCACHE_MOUNTED|DCACHE_NEED_AUTOMOUNT)
+
+static inline bool d_mountpoint(const struct dentry *dentry)
+{
+	return dentry->d_flags & DCACHE_MOUNTED;
+}
+
+/*
+ * Directory cache entry type accessor functions.
+ */
+static inline unsigned __d_entry_type(const struct dentry *dentry)
+{
+	return dentry->d_flags & DCACHE_ENTRY_TYPE;
+}
+
+static inline bool d_is_miss(const struct dentry *dentry)
+{
+	return __d_entry_type(dentry) == DCACHE_MISS_TYPE;
+}
+
+static inline bool d_can_lookup(const struct dentry *dentry)
+{
+	return __d_entry_type(dentry) == DCACHE_DIRECTORY_TYPE;
+}
+
+static inline bool d_is_autodir(const struct dentry *dentry)
+{
+	return __d_entry_type(dentry) == DCACHE_AUTODIR_TYPE;
+}
+
+static inline bool d_is_dir(const struct dentry *dentry)
+{
+	return d_can_lookup(dentry) || d_is_autodir(dentry);
+}
+
+static inline bool d_is_symlink(const struct dentry *dentry)
+{
+	return __d_entry_type(dentry) == DCACHE_SYMLINK_TYPE;
+}
+
+static inline bool d_is_reg(const struct dentry *dentry)
+{
+	return __d_entry_type(dentry) == DCACHE_REGULAR_TYPE;
+}
+
+static inline bool d_is_special(const struct dentry *dentry)
+{
+	return __d_entry_type(dentry) == DCACHE_SPECIAL_TYPE;
+}
+
+static inline bool d_is_file(const struct dentry *dentry)
+{
+	return d_is_reg(dentry) || d_is_special(dentry);
+}
+
+static inline bool d_is_negative(const struct dentry *dentry)
+{
+	// TODO: check d_is_whiteout(dentry) also.
+	return d_is_miss(dentry);
+}
+
+static inline bool d_is_positive(const struct dentry *dentry)
+{
+	return !d_is_negative(dentry);
+}
+
+static inline struct inode *d_inode(const struct dentry *dentry)
+{
+	return dentry->d_inode;
+}
+
+#define IS_ROOT(x) ((x) == (x)->d_parent)
+
+char *dpath(struct dentry *dentry, struct dentry *root);
+
 #endif	/* __LINUX_DCACHE_H */
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 153c464470..4550e8feeb 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -34,7 +34,18 @@
 #define DT_SOCK		12
 #define DT_WHT		14
 
+/*
+ * This is the "filldir" function type, used by readdir() to let
+ * the kernel specify what kind of dirent layout it wants to have.
+ * This allows the kernel to read directories into kernel space or
+ * to have different dirent layouts depending on the binary type.
+ */
+struct dir_context;
+typedef int (*filldir_t)(struct dir_context *, const char *, int, loff_t, u64,
+			 unsigned);
+
 struct dir_context {
+	const filldir_t actor;
 	loff_t pos;
 };
 
@@ -94,12 +105,8 @@ struct inode {
 	};
 	uid_t			i_uid;
 	gid_t			i_gid;
-	dev_t			i_rdev;
 	u64			i_version;
 	loff_t			i_size;
-#ifdef __NEED_I_SIZE_ORDERED
-	seqcount_t		i_size_seqcount;
-#endif
 	struct timespec		i_atime;
 	struct timespec		i_mtime;
 	struct timespec		i_ctime;
@@ -107,39 +114,19 @@ struct inode {
 	blkcnt_t		i_blocks;
 	unsigned short          i_bytes;
 	umode_t			i_mode;
-	spinlock_t		i_lock;	/* i_blocks, i_bytes, maybe i_size */
-	struct mutex		i_mutex;
-	struct rw_semaphore	i_alloc_sem;
 	const struct inode_operations	*i_op;
 	const struct file_operations	*i_fop;	/* former ->i_op->default_file_ops */
 	struct super_block	*i_sb;
-	struct file_lock	*i_flock;
-#ifdef CONFIG_QUOTA
-	struct dquot		*i_dquot[MAXQUOTAS];
-#endif
-	struct list_head	i_devices;
-	int			i_cindex;
 
 	__u32			i_generation;
 
-#ifdef CONFIG_DNOTIFY
-	unsigned long		i_dnotify_mask; /* Directory notify events */
-	struct dnotify_struct	*i_dnotify; /* for directory notifications */
-#endif
-
-#ifdef CONFIG_INOTIFY
-	struct list_head	inotify_watches; /* watches on this inode */
-	struct mutex		inotify_mutex;	/* protects the watches list */
-#endif
-
 	unsigned long		i_state;
-	unsigned long		dirtied_when;	/* jiffies of first dirtying */
 
 	unsigned int		i_flags;
+	unsigned int		i_count;
+
+	char			*i_link;
 
-#ifdef CONFIG_SECURITY
-	void			*i_security;
-#endif
 	void			*i_private; /* fs or device private pointer */
 };
 
@@ -199,19 +186,9 @@ struct super_block {
 	   Cannot be worse than a second */
 	u32		   s_time_gran;
 
-	/*
-	 * Filesystem subtype.  If non-empty the filesystem type field
-	 * in /proc/mounts will be "type.subtype"
-	 */
-	char *s_subtype;
-
-	/*
-	 * Saved mount options for lazy filesystems using
-	 * generic_show_options()
-	 */
-	char *s_options;
-
 	/* Number of inodes with nlink == 0 but still referenced */
+
+	const struct dentry_operations *s_d_op; /* default d_op for dentries */
 };
 
 struct file_system_type {
@@ -405,4 +382,80 @@ static inline loff_t i_size_read(const struct inode *inode)
 	return inode->i_size;
 }
 
+struct inode *new_inode(struct super_block *sb);
+unsigned int get_next_ino(void);
+void iput(struct inode *);
+struct inode *iget(struct inode *);
+void inc_nlink(struct inode *inode);
+
+struct inode_operations {
+	struct dentry * (*lookup) (struct inode *,struct dentry *, unsigned int);
+
+	const char *(*get_link) (struct dentry *dentry, struct inode *inode);
+
+	int (*create) (struct inode *,struct dentry *, umode_t);
+	int (*link) (struct dentry *,struct inode *,struct dentry *);
+	int (*unlink) (struct inode *,struct dentry *);
+	int (*symlink) (struct inode *,struct dentry *,const char *);
+	int (*mkdir) (struct inode *,struct dentry *,umode_t);
+	int (*rmdir) (struct inode *,struct dentry *);
+	int (*rename) (struct inode *, struct dentry *,
+		       struct inode *, struct dentry *, unsigned int);
+};
+
+static inline ino_t parent_ino(struct dentry *dentry)
+{
+	return dentry->d_parent->d_inode->i_ino;
+}
+
+static inline bool dir_emit(struct dir_context *ctx,
+			    const char *name, int namelen,
+			    u64 ino, unsigned type)
+{
+	return ctx->actor(ctx, name, namelen, ctx->pos, ino, type) == 0;
+}
+
+static inline bool dir_emit_dot(struct file *file, struct dir_context *ctx)
+{
+	return ctx->actor(ctx, ".", 1, ctx->pos,
+			file->f_path.dentry->d_inode->i_ino, DT_DIR) == 0;
+}
+static inline bool dir_emit_dotdot(struct file *file, struct dir_context *ctx)
+{
+	return ctx->actor(ctx, "..", 2, ctx->pos,
+			parent_ino(file->f_path.dentry), DT_DIR) == 0;
+}
+
+static inline void dir_emit_dots(struct file *file, struct dir_context *ctx)
+{
+	if (ctx->pos == 0) {
+		dir_emit_dot(file, ctx);
+		ctx->pos = 1;
+	}
+	if (ctx->pos == 1) {
+		dir_emit_dotdot(file, ctx);
+		ctx->pos = 2;
+	}
+}
+
+struct file_operations {
+	int (*iterate) (struct file *, struct dir_context *);
+	ssize_t (*read) (struct file *, char __user *, size_t, loff_t *);
+	ssize_t (*write) (struct file *, const char __user *, size_t, loff_t *);
+	int (*ioctl) (struct file *, int request, void *buf);
+	int (*truncate) (struct file *, loff_t);
+};
+
+void drop_nlink(struct inode *inode);
+
+extern const struct file_operations simple_dir_operations;
+extern const struct inode_operations simple_symlink_inode_operations;
+
+int simple_empty(struct dentry *dentry);
+int simple_unlink(struct inode *dir, struct dentry *dentry);
+int simple_rmdir(struct inode *dir, struct dentry *dentry);
+struct dentry *simple_lookup(struct inode *, struct dentry *, unsigned int flags);
+int dcache_readdir(struct file *, struct dir_context *);
+const char *simple_get_link(struct dentry *dentry, struct inode *inode);
+
 #endif /* _LINUX_FS_H */
diff --git a/include/linux/mount.h b/include/linux/mount.h
index 57d5ba9523..9557365fb5 100644
--- a/include/linux/mount.h
+++ b/include/linux/mount.h
@@ -14,8 +14,11 @@
 
 struct vfsmount {
 	struct dentry *mnt_root;	/* root of the mounted tree */
+	struct dentry *mountpoint;	/* where it's mounted (barebox specific, no support */
+	struct vfsmount *parent;	/* for bind mounts and the like) */
 	struct super_block *mnt_sb;	/* pointer to superblock */
 	int mnt_flags;
+	int ref;
 };
 
 #endif /* _LINUX_MOUNT_H */
diff --git a/include/linux/namei.h b/include/linux/namei.h
new file mode 100644
index 0000000000..8ed7f8a1cd
--- /dev/null
+++ b/include/linux/namei.h
@@ -0,0 +1,52 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_NAMEI_H
+#define _LINUX_NAMEI_H
+
+#include <linux/kernel.h>
+#include <linux/path.h>
+
+enum { MAX_NESTED_LINKS = 8 };
+
+#define MAXSYMLINKS 40
+
+/*
+ * Type of the last component on LOOKUP_PARENT
+ */
+enum {LAST_NORM, LAST_ROOT, LAST_DOT, LAST_DOTDOT, LAST_BIND};
+
+/*
+ * The bitmask for a lookup event:
+ *  - follow links at the end
+ *  - require a directory
+ *  - ending slashes ok even for nonexistent files
+ *  - internal "there are more path components" flag
+ *  - dentry cache is untrusted; force a real lookup
+ *  - suppress terminal automount
+ */
+#define LOOKUP_FOLLOW		0x0001
+#define LOOKUP_DIRECTORY	0x0002
+#define LOOKUP_AUTOMOUNT	0x0004
+
+#define LOOKUP_PARENT		0x0010
+#define LOOKUP_REVAL		0x0020
+#define LOOKUP_RCU		0x0040
+#define LOOKUP_NO_REVAL		0x0080
+
+/*
+ * Intent data
+ */
+#define LOOKUP_OPEN		0x0100
+#define LOOKUP_CREATE		0x0200
+#define LOOKUP_EXCL		0x0400
+#define LOOKUP_RENAME_TARGET	0x0800
+
+#define LOOKUP_JUMPED		0x1000
+#define LOOKUP_ROOT		0x2000
+#define LOOKUP_EMPTY		0x4000
+#define LOOKUP_DOWN		0x8000
+
+#define AT_FDCWD                -100    /* Special value used to indicate
+                                           openat should use the current
+                                           working directory. */
+
+#endif /* _LINUX_NAMEI_H */
diff --git a/include/linux/stat.h b/include/linux/stat.h
index af022c5c79..87fe068396 100644
--- a/include/linux/stat.h
+++ b/include/linux/stat.h
@@ -42,6 +42,8 @@ extern "C" {
 #define S_IWOTH 00002		/* read permission for other */
 #define S_IXOTH 00001		/* execute/search permission for other */
 
+#define S_IRWXUGO	(S_IRWXU|S_IRWXG|S_IRWXO)
+
 struct stat {
 	unsigned short st_dev;
 	unsigned short __pad1;