Adding upstream version 5.10.209.upstream/5.10.209upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1239 insertions, 0 deletions

diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
new file mode 100644
index 000000000..ceaa68683
--- /dev/null
+++ b/fs/fuse/fuse_i.h
@@ -0,0 +1,1239 @@
+/*
+  FUSE: Filesystem in Userspace
+  Copyright (C) 2001-2008  Miklos Szeredi <miklos@szeredi.hu>
+
+  This program can be distributed under the terms of the GNU GPL.
+  See the file COPYING.
+*/
+
+#ifndef _FS_FUSE_I_H
+#define _FS_FUSE_I_H
+
+#ifndef pr_fmt
+# define pr_fmt(fmt) "fuse: " fmt
+#endif
+
+#include <linux/fuse.h>
+#include <linux/fs.h>
+#include <linux/mount.h>
+#include <linux/wait.h>
+#include <linux/list.h>
+#include <linux/spinlock.h>
+#include <linux/mm.h>
+#include <linux/backing-dev.h>
+#include <linux/mutex.h>
+#include <linux/rwsem.h>
+#include <linux/rbtree.h>
+#include <linux/poll.h>
+#include <linux/workqueue.h>
+#include <linux/kref.h>
+#include <linux/xattr.h>
+#include <linux/pid_namespace.h>
+#include <linux/refcount.h>
+#include <linux/user_namespace.h>
+
+/** Default max number of pages that can be used in a single read request */
+#define FUSE_DEFAULT_MAX_PAGES_PER_REQ 32
+
+/** Maximum of max_pages received in init_out */
+#define FUSE_MAX_MAX_PAGES 256
+
+/** Bias for fi->writectr, meaning new writepages must not be sent */
+#define FUSE_NOWRITE INT_MIN
+
+/** It could be as large as PATH_MAX, but would that have any uses? */
+#define FUSE_NAME_MAX 1024
+
+/** Number of dentries for each connection in the control filesystem */
+#define FUSE_CTL_NUM_DENTRIES 5
+
+/** List of active connections */
+extern struct list_head fuse_conn_list;
+
+/** Global mutex protecting fuse_conn_list and the control filesystem */
+extern struct mutex fuse_mutex;
+
+/** Module parameters */
+extern unsigned max_user_bgreq;
+extern unsigned max_user_congthresh;
+
+/* One forget request */
+struct fuse_forget_link {
+	struct fuse_forget_one forget_one;
+	struct fuse_forget_link *next;
+};
+
+/** FUSE inode */
+struct fuse_inode {
+	/** Inode data */
+	struct inode inode;
+
+	/** Unique ID, which identifies the inode between userspace
+	 * and kernel */
+	u64 nodeid;
+
+	/** Number of lookups on this inode */
+	u64 nlookup;
+
+	/** The request used for sending the FORGET message */
+	struct fuse_forget_link *forget;
+
+	/** Time in jiffies until the file attributes are valid */
+	u64 i_time;
+
+	/* Which attributes are invalid */
+	u32 inval_mask;
+
+	/** The sticky bit in inode->i_mode may have been removed, so
+	    preserve the original mode */
+	umode_t orig_i_mode;
+
+	/** 64 bit inode number */
+	u64 orig_ino;
+
+	/** Version of last attribute change */
+	u64 attr_version;
+
+	union {
+		/* Write related fields (regular file only) */
+		struct {
+			/* Files usable in writepage.  Protected by fi->lock */
+			struct list_head write_files;
+
+			/* Writepages pending on truncate or fsync */
+			struct list_head queued_writes;
+
+			/* Number of sent writes, a negative bias
+			 * (FUSE_NOWRITE) means more writes are blocked */
+			int writectr;
+
+			/* Waitq for writepage completion */
+			wait_queue_head_t page_waitq;
+
+			/* List of writepage requestst (pending or sent) */
+			struct rb_root writepages;
+		};
+
+		/* readdir cache (directory only) */
+		struct {
+			/* true if fully cached */
+			bool cached;
+
+			/* size of cache */
+			loff_t size;
+
+			/* position at end of cache (position of next entry) */
+			loff_t pos;
+
+			/* version of the cache */
+			u64 version;
+
+			/* modification time of directory when cache was
+			 * started */
+			struct timespec64 mtime;
+
+			/* iversion of directory when cache was started */
+			u64 iversion;
+
+			/* protects above fields */
+			spinlock_t lock;
+		} rdc;
+	};
+
+	/** Miscellaneous bits describing inode state */
+	unsigned long state;
+
+	/** Lock for serializing lookup and readdir for back compatibility*/
+	struct mutex mutex;
+
+	/** Lock to protect write related fields */
+	spinlock_t lock;
+
+	/**
+	 * Can't take inode lock in fault path (leads to circular dependency).
+	 * Introduce another semaphore which can be taken in fault path and
+	 * then other filesystem paths can take this to block faults.
+	 */
+	struct rw_semaphore i_mmap_sem;
+
+#ifdef CONFIG_FUSE_DAX
+	/*
+	 * Dax specific inode data
+	 */
+	struct fuse_inode_dax *dax;
+#endif
+};
+
+/** FUSE inode state bits */
+enum {
+	/** Advise readdirplus  */
+	FUSE_I_ADVISE_RDPLUS,
+	/** Initialized with readdirplus */
+	FUSE_I_INIT_RDPLUS,
+	/** An operation changing file size is in progress  */
+	FUSE_I_SIZE_UNSTABLE,
+	/* Bad inode */
+	FUSE_I_BAD,
+};
+
+struct fuse_conn;
+struct fuse_mount;
+struct fuse_release_args;
+
+/** FUSE specific file data */
+struct fuse_file {
+	/** Fuse connection for this file */
+	struct fuse_mount *fm;
+
+	/* Argument space reserved for release */
+	struct fuse_release_args *release_args;
+
+	/** Kernel file handle guaranteed to be unique */
+	u64 kh;
+
+	/** File handle used by userspace */
+	u64 fh;
+
+	/** Node id of this file */
+	u64 nodeid;
+
+	/** Refcount */
+	refcount_t count;
+
+	/** FOPEN_* flags returned by open */
+	u32 open_flags;
+
+	/** Entry on inode's write_files list */
+	struct list_head write_entry;
+
+	/* Readdir related */
+	struct {
+		/*
+		 * Protects below fields against (crazy) parallel readdir on
+		 * same open file.  Uncontended in the normal case.
+		 */
+		struct mutex lock;
+
+		/* Dir stream position */
+		loff_t pos;
+
+		/* Offset in cache */
+		loff_t cache_off;
+
+		/* Version of cache we are reading */
+		u64 version;
+
+	} readdir;
+
+	/** RB node to be linked on fuse_conn->polled_files */
+	struct rb_node polled_node;
+
+	/** Wait queue head for poll */
+	wait_queue_head_t poll_wait;
+
+	/** Has flock been performed on this file? */
+	bool flock:1;
+};
+
+/** One input argument of a request */
+struct fuse_in_arg {
+	unsigned size;
+	const void *value;
+};
+
+/** One output argument of a request */
+struct fuse_arg {
+	unsigned size;
+	void *value;
+};
+
+/** FUSE page descriptor */
+struct fuse_page_desc {
+	unsigned int length;
+	unsigned int offset;
+};
+
+struct fuse_args {
+	uint64_t nodeid;
+	uint32_t opcode;
+	unsigned short in_numargs;
+	unsigned short out_numargs;
+	bool force:1;
+	bool noreply:1;
+	bool nocreds:1;
+	bool in_pages:1;
+	bool out_pages:1;
+	bool user_pages:1;
+	bool out_argvar:1;
+	bool page_zeroing:1;
+	bool page_replace:1;
+	bool may_block:1;
+	struct fuse_in_arg in_args[3];
+	struct fuse_arg out_args[2];
+	void (*end)(struct fuse_mount *fm, struct fuse_args *args, int error);
+};
+
+struct fuse_args_pages {
+	struct fuse_args args;
+	struct page **pages;
+	struct fuse_page_desc *descs;
+	unsigned int num_pages;
+};
+
+#define FUSE_ARGS(args) struct fuse_args args = {}
+
+/** The request IO state (for asynchronous processing) */
+struct fuse_io_priv {
+	struct kref refcnt;
+	int async;
+	spinlock_t lock;
+	unsigned reqs;
+	ssize_t bytes;
+	size_t size;
+	__u64 offset;
+	bool write;
+	bool should_dirty;
+	int err;
+	struct kiocb *iocb;
+	struct completion *done;
+	bool blocking;
+};
+
+#define FUSE_IO_PRIV_SYNC(i) \
+{					\
+	.refcnt = KREF_INIT(1),		\
+	.async = 0,			\
+	.iocb = i,			\
+}
+
+/**
+ * Request flags
+ *
+ * FR_ISREPLY:		set if the request has reply
+ * FR_FORCE:		force sending of the request even if interrupted
+ * FR_BACKGROUND:	request is sent in the background
+ * FR_WAITING:		request is counted as "waiting"
+ * FR_ABORTED:		the request was aborted
+ * FR_INTERRUPTED:	the request has been interrupted
+ * FR_LOCKED:		data is being copied to/from the request
+ * FR_PENDING:		request is not yet in userspace
+ * FR_SENT:		request is in userspace, waiting for an answer
+ * FR_FINISHED:		request is finished
+ * FR_PRIVATE:		request is on private list
+ * FR_ASYNC:		request is asynchronous
+ */
+enum fuse_req_flag {
+	FR_ISREPLY,
+	FR_FORCE,
+	FR_BACKGROUND,
+	FR_WAITING,
+	FR_ABORTED,
+	FR_INTERRUPTED,
+	FR_LOCKED,
+	FR_PENDING,
+	FR_SENT,
+	FR_FINISHED,
+	FR_PRIVATE,
+	FR_ASYNC,
+};
+
+/**
+ * A request to the client
+ *
+ * .waitq.lock protects the following fields:
+ *   - FR_ABORTED
+ *   - FR_LOCKED (may also be modified under fc->lock, tested under both)
+ */
+struct fuse_req {
+	/** This can be on either pending processing or io lists in
+	    fuse_conn */
+	struct list_head list;
+
+	/** Entry on the interrupts list  */
+	struct list_head intr_entry;
+
+	/* Input/output arguments */
+	struct fuse_args *args;
+
+	/** refcount */
+	refcount_t count;
+
+	/* Request flags, updated with test/set/clear_bit() */
+	unsigned long flags;
+
+	/* The request input header */
+	struct {
+		struct fuse_in_header h;
+	} in;
+
+	/* The request output header */
+	struct {
+		struct fuse_out_header h;
+	} out;
+
+	/** Used to wake up the task waiting for completion of request*/
+	wait_queue_head_t waitq;
+
+#if IS_ENABLED(CONFIG_VIRTIO_FS)
+	/** virtio-fs's physically contiguous buffer for in and out args */
+	void *argbuf;
+#endif
+
+	/** fuse_mount this request belongs to */
+	struct fuse_mount *fm;
+};
+
+struct fuse_iqueue;
+
+/**
+ * Input queue callbacks
+ *
+ * Input queue signalling is device-specific.  For example, the /dev/fuse file
+ * uses fiq->waitq and fasync to wake processes that are waiting on queue
+ * readiness.  These callbacks allow other device types to respond to input
+ * queue activity.
+ */
+struct fuse_iqueue_ops {
+	/**
+	 * Signal that a forget has been queued
+	 */
+	void (*wake_forget_and_unlock)(struct fuse_iqueue *fiq)
+		__releases(fiq->lock);
+
+	/**
+	 * Signal that an INTERRUPT request has been queued
+	 */
+	void (*wake_interrupt_and_unlock)(struct fuse_iqueue *fiq)
+		__releases(fiq->lock);
+
+	/**
+	 * Signal that a request has been queued
+	 */
+	void (*wake_pending_and_unlock)(struct fuse_iqueue *fiq)
+		__releases(fiq->lock);
+
+	/**
+	 * Clean up when fuse_iqueue is destroyed
+	 */
+	void (*release)(struct fuse_iqueue *fiq);
+};
+
+/** /dev/fuse input queue operations */
+extern const struct fuse_iqueue_ops fuse_dev_fiq_ops;
+
+struct fuse_iqueue {
+	/** Connection established */
+	unsigned connected;
+
+	/** Lock protecting accesses to members of this structure */
+	spinlock_t lock;
+
+	/** Readers of the connection are waiting on this */
+	wait_queue_head_t waitq;
+
+	/** The next unique request id */
+	u64 reqctr;
+
+	/** The list of pending requests */
+	struct list_head pending;
+
+	/** Pending interrupts */
+	struct list_head interrupts;
+
+	/** Queue of pending forgets */
+	struct fuse_forget_link forget_list_head;
+	struct fuse_forget_link *forget_list_tail;
+
+	/** Batching of FORGET requests (positive indicates FORGET batch) */
+	int forget_batch;
+
+	/** O_ASYNC requests */
+	struct fasync_struct *fasync;
+
+	/** Device-specific callbacks */
+	const struct fuse_iqueue_ops *ops;
+
+	/** Device-specific state */
+	void *priv;
+};
+
+#define FUSE_PQ_HASH_BITS 8
+#define FUSE_PQ_HASH_SIZE (1 << FUSE_PQ_HASH_BITS)
+
+struct fuse_pqueue {
+	/** Connection established */
+	unsigned connected;
+
+	/** Lock protecting accessess to  members of this structure */
+	spinlock_t lock;
+
+	/** Hash table of requests being processed */
+	struct list_head *processing;
+
+	/** The list of requests under I/O */
+	struct list_head io;
+};
+
+/**
+ * Fuse device instance
+ */
+struct fuse_dev {
+	/** Fuse connection for this device */
+	struct fuse_conn *fc;
+
+	/** Processing queue */
+	struct fuse_pqueue pq;
+
+	/** list entry on fc->devices */
+	struct list_head entry;
+};
+
+struct fuse_fs_context {
+	int fd;
+	unsigned int rootmode;
+	kuid_t user_id;
+	kgid_t group_id;
+	bool is_bdev:1;
+	bool fd_present:1;
+	bool rootmode_present:1;
+	bool user_id_present:1;
+	bool group_id_present:1;
+	bool default_permissions:1;
+	bool allow_other:1;
+	bool destroy:1;
+	bool no_control:1;
+	bool no_force_umount:1;
+	bool legacy_opts_show:1;
+	bool dax:1;
+	unsigned int max_read;
+	unsigned int blksize;
+	const char *subtype;
+
+	/* DAX device, may be NULL */
+	struct dax_device *dax_dev;
+
+	/* fuse_dev pointer to fill in, should contain NULL on entry */
+	void **fudptr;
+};
+
+/**
+ * A Fuse connection.
+ *
+ * This structure is created, when the root filesystem is mounted, and
+ * is destroyed, when the client device is closed and the last
+ * fuse_mount is destroyed.
+ */
+struct fuse_conn {
+	/** Lock protecting accessess to  members of this structure */
+	spinlock_t lock;
+
+	/** Refcount */
+	refcount_t count;
+
+	/** Number of fuse_dev's */
+	atomic_t dev_count;
+
+	struct rcu_head rcu;
+
+	/** The user id for this mount */
+	kuid_t user_id;
+
+	/** The group id for this mount */
+	kgid_t group_id;
+
+	/** The pid namespace for this mount */
+	struct pid_namespace *pid_ns;
+
+	/** The user namespace for this mount */
+	struct user_namespace *user_ns;
+
+	/** Maximum read size */
+	unsigned max_read;
+
+	/** Maximum write size */
+	unsigned max_write;
+
+	/** Maxmum number of pages that can be used in a single request */
+	unsigned int max_pages;
+
+	/** Constrain ->max_pages to this value during feature negotiation */
+	unsigned int max_pages_limit;
+
+	/** Input queue */
+	struct fuse_iqueue iq;
+
+	/** The next unique kernel file handle */
+	atomic64_t khctr;
+
+	/** rbtree of fuse_files waiting for poll events indexed by ph */
+	struct rb_root polled_files;
+
+	/** Maximum number of outstanding background requests */
+	unsigned max_background;
+
+	/** Number of background requests at which congestion starts */
+	unsigned congestion_threshold;
+
+	/** Number of requests currently in the background */
+	unsigned num_background;
+
+	/** Number of background requests currently queued for userspace */
+	unsigned active_background;
+
+	/** The list of background requests set aside for later queuing */
+	struct list_head bg_queue;
+
+	/** Protects: max_background, congestion_threshold, num_background,
+	 * active_background, bg_queue, blocked */
+	spinlock_t bg_lock;
+
+	/** Flag indicating that INIT reply has been received. Allocating
+	 * any fuse request will be suspended until the flag is set */
+	int initialized;
+
+	/** Flag indicating if connection is blocked.  This will be
+	    the case before the INIT reply is received, and if there
+	    are too many outstading backgrounds requests */
+	int blocked;
+
+	/** waitq for blocked connection */
+	wait_queue_head_t blocked_waitq;
+
+	/** Connection established, cleared on umount, connection
+	    abort and device release */
+	unsigned connected;
+
+	/** Connection aborted via sysfs */
+	bool aborted;
+
+	/** Connection failed (version mismatch).  Cannot race with
+	    setting other bitfields since it is only set once in INIT
+	    reply, before any other request, and never cleared */
+	unsigned conn_error:1;
+
+	/** Connection successful.  Only set in INIT */
+	unsigned conn_init:1;
+
+	/** Do readpages asynchronously?  Only set in INIT */
+	unsigned async_read:1;
+
+	/** Return an unique read error after abort.  Only set in INIT */
+	unsigned abort_err:1;
+
+	/** Do not send separate SETATTR request before open(O_TRUNC)  */
+	unsigned atomic_o_trunc:1;
+
+	/** Filesystem supports NFS exporting.  Only set in INIT */
+	unsigned export_support:1;
+
+	/** write-back cache policy (default is write-through) */
+	unsigned writeback_cache:1;
+
+	/** allow parallel lookups and readdir (default is serialized) */
+	unsigned parallel_dirops:1;
+
+	/** handle fs handles killing suid/sgid/cap on write/chown/trunc */
+	unsigned handle_killpriv:1;
+
+	/** cache READLINK responses in page cache */
+	unsigned cache_symlinks:1;
+
+	/* show legacy mount options */
+	unsigned int legacy_opts_show:1;
+
+	/*
+	 * The following bitfields are only for optimization purposes
+	 * and hence races in setting them will not cause malfunction
+	 */
+
+	/** Is open/release not implemented by fs? */
+	unsigned no_open:1;
+
+	/** Is opendir/releasedir not implemented by fs? */
+	unsigned no_opendir:1;
+
+	/** Is fsync not implemented by fs? */
+	unsigned no_fsync:1;
+
+	/** Is fsyncdir not implemented by fs? */
+	unsigned no_fsyncdir:1;
+
+	/** Is flush not implemented by fs? */
+	unsigned no_flush:1;
+
+	/** Is setxattr not implemented by fs? */
+	unsigned no_setxattr:1;
+
+	/** Is getxattr not implemented by fs? */
+	unsigned no_getxattr:1;
+
+	/** Is listxattr not implemented by fs? */
+	unsigned no_listxattr:1;
+
+	/** Is removexattr not implemented by fs? */
+	unsigned no_removexattr:1;
+
+	/** Are posix file locking primitives not implemented by fs? */
+	unsigned no_lock:1;
+
+	/** Is access not implemented by fs? */
+	unsigned no_access:1;
+
+	/** Is create not implemented by fs? */
+	unsigned no_create:1;
+
+	/** Is interrupt not implemented by fs? */
+	unsigned no_interrupt:1;
+
+	/** Is bmap not implemented by fs? */
+	unsigned no_bmap:1;
+
+	/** Is poll not implemented by fs? */
+	unsigned no_poll:1;
+
+	/** Do multi-page cached writes */
+	unsigned big_writes:1;
+
+	/** Don't apply umask to creation modes */
+	unsigned dont_mask:1;
+
+	/** Are BSD file locking primitives not implemented by fs? */
+	unsigned no_flock:1;
+
+	/** Is fallocate not implemented by fs? */
+	unsigned no_fallocate:1;
+
+	/** Is rename with flags implemented by fs? */
+	unsigned no_rename2:1;
+
+	/** Use enhanced/automatic page cache invalidation. */
+	unsigned auto_inval_data:1;
+
+	/** Filesystem is fully reponsible for page cache invalidation. */
+	unsigned explicit_inval_data:1;
+
+	/** Does the filesystem support readdirplus? */
+	unsigned do_readdirplus:1;
+
+	/** Does the filesystem want adaptive readdirplus? */
+	unsigned readdirplus_auto:1;
+
+	/** Does the filesystem support asynchronous direct-IO submission? */
+	unsigned async_dio:1;
+
+	/** Is lseek not implemented by fs? */
+	unsigned no_lseek:1;
+
+	/** Does the filesystem support posix acls? */
+	unsigned posix_acl:1;
+
+	/** Check permissions based on the file mode or not? */
+	unsigned default_permissions:1;
+
+	/** Allow other than the mounter user to access the filesystem ? */
+	unsigned allow_other:1;
+
+	/** Does the filesystem support copy_file_range? */
+	unsigned no_copy_file_range:1;
+
+	/* Send DESTROY request */
+	unsigned int destroy:1;
+
+	/* Delete dentries that have gone stale */
+	unsigned int delete_stale:1;
+
+	/** Do not create entry in fusectl fs */
+	unsigned int no_control:1;
+
+	/** Do not allow MNT_FORCE umount */
+	unsigned int no_force_umount:1;
+
+	/* Auto-mount submounts announced by the server */
+	unsigned int auto_submounts:1;
+
+	/** The number of requests waiting for completion */
+	atomic_t num_waiting;
+
+	/** Negotiated minor version */
+	unsigned minor;
+
+	/** Entry on the fuse_mount_list */
+	struct list_head entry;
+
+	/** Device ID from the root super block */
+	dev_t dev;
+
+	/** Dentries in the control filesystem */
+	struct dentry *ctl_dentry[FUSE_CTL_NUM_DENTRIES];
+
+	/** number of dentries used in the above array */
+	int ctl_ndents;
+
+	/** Key for lock owner ID scrambling */
+	u32 scramble_key[4];
+
+	/** Version counter for attribute changes */
+	atomic64_t attr_version;
+
+	/** Called on final put */
+	void (*release)(struct fuse_conn *);
+
+	/**
+	 * Read/write semaphore to hold when accessing the sb of any
+	 * fuse_mount belonging to this connection
+	 */
+	struct rw_semaphore killsb;
+
+	/** List of device instances belonging to this connection */
+	struct list_head devices;
+
+#ifdef CONFIG_FUSE_DAX
+	/* Dax specific conn data, non-NULL if DAX is enabled */
+	struct fuse_conn_dax *dax;
+#endif
+
+	/** List of filesystems using this connection */
+	struct list_head mounts;
+};
+
+/*
+ * Represents a mounted filesystem, potentially a submount.
+ *
+ * This object allows sharing a fuse_conn between separate mounts to
+ * allow submounts with dedicated superblocks and thus separate device
+ * IDs.
+ */
+struct fuse_mount {
+	/* Underlying (potentially shared) connection to the FUSE server */
+	struct fuse_conn *fc;
+
+	/* Refcount */
+	refcount_t count;
+
+	/*
+	 * Super block for this connection (fc->killsb must be held when
+	 * accessing this).
+	 */
+	struct super_block *sb;
+
+	/* Entry on fc->mounts */
+	struct list_head fc_entry;
+};
+
+static inline struct fuse_mount *get_fuse_mount_super(struct super_block *sb)
+{
+	return sb->s_fs_info;
+}
+
+static inline struct fuse_conn *get_fuse_conn_super(struct super_block *sb)
+{
+	struct fuse_mount *fm = get_fuse_mount_super(sb);
+
+	return fm ? fm->fc : NULL;
+}
+
+static inline struct fuse_mount *get_fuse_mount(struct inode *inode)
+{
+	return get_fuse_mount_super(inode->i_sb);
+}
+
+static inline struct fuse_conn *get_fuse_conn(struct inode *inode)
+{
+	struct fuse_mount *fm = get_fuse_mount(inode);
+
+	return fm ? fm->fc : NULL;
+}
+
+static inline struct fuse_inode *get_fuse_inode(struct inode *inode)
+{
+	return container_of(inode, struct fuse_inode, inode);
+}
+
+static inline u64 get_node_id(struct inode *inode)
+{
+	return get_fuse_inode(inode)->nodeid;
+}
+
+static inline int invalid_nodeid(u64 nodeid)
+{
+	return !nodeid || nodeid == FUSE_ROOT_ID;
+}
+
+static inline u64 fuse_get_attr_version(struct fuse_conn *fc)
+{
+	return atomic64_read(&fc->attr_version);
+}
+
+static inline bool fuse_stale_inode(const struct inode *inode, int generation,
+				    struct fuse_attr *attr)
+{
+	return inode->i_generation != generation ||
+		inode_wrong_type(inode, attr->mode);
+}
+
+static inline void fuse_make_bad(struct inode *inode)
+{
+	remove_inode_hash(inode);
+	set_bit(FUSE_I_BAD, &get_fuse_inode(inode)->state);
+}
+
+static inline bool fuse_is_bad(struct inode *inode)
+{
+	return unlikely(test_bit(FUSE_I_BAD, &get_fuse_inode(inode)->state));
+}
+
+/** Device operations */
+extern const struct file_operations fuse_dev_operations;
+
+extern const struct dentry_operations fuse_dentry_operations;
+extern const struct dentry_operations fuse_root_dentry_operations;
+
+/**
+ * Get a filled in inode
+ */
+struct inode *fuse_iget(struct super_block *sb, u64 nodeid,
+			int generation, struct fuse_attr *attr,
+			u64 attr_valid, u64 attr_version);
+
+int fuse_lookup_name(struct super_block *sb, u64 nodeid, const struct qstr *name,
+		     struct fuse_entry_out *outarg, struct inode **inode);
+
+/**
+ * Send FORGET command
+ */
+void fuse_queue_forget(struct fuse_conn *fc, struct fuse_forget_link *forget,
+		       u64 nodeid, u64 nlookup);
+
+struct fuse_forget_link *fuse_alloc_forget(void);
+
+struct fuse_forget_link *fuse_dequeue_forget(struct fuse_iqueue *fiq,
+					     unsigned int max,
+					     unsigned int *countp);
+
+/*
+ * Initialize READ or READDIR request
+ */
+struct fuse_io_args {
+	union {
+		struct {
+			struct fuse_read_in in;
+			u64 attr_ver;
+		} read;
+		struct {
+			struct fuse_write_in in;
+			struct fuse_write_out out;
+			bool page_locked;
+		} write;
+	};
+	struct fuse_args_pages ap;
+	struct fuse_io_priv *io;
+	struct fuse_file *ff;
+};
+
+void fuse_read_args_fill(struct fuse_io_args *ia, struct file *file, loff_t pos,
+			 size_t count, int opcode);
+
+
+/**
+ * Send OPEN or OPENDIR request
+ */
+int fuse_open_common(struct inode *inode, struct file *file, bool isdir);
+
+struct fuse_file *fuse_file_alloc(struct fuse_mount *fm);
+void fuse_file_free(struct fuse_file *ff);
+void fuse_finish_open(struct inode *inode, struct file *file);
+
+void fuse_sync_release(struct fuse_inode *fi, struct fuse_file *ff, int flags);
+
+/**
+ * Send RELEASE or RELEASEDIR request
+ */
+void fuse_release_common(struct file *file, bool isdir);
+
+/**
+ * Send FSYNC or FSYNCDIR request
+ */
+int fuse_fsync_common(struct file *file, loff_t start, loff_t end,
+		      int datasync, int opcode);
+
+/**
+ * Notify poll wakeup
+ */
+int fuse_notify_poll_wakeup(struct fuse_conn *fc,
+			    struct fuse_notify_poll_wakeup_out *outarg);
+
+/**
+ * Initialize file operations on a regular file
+ */
+void fuse_init_file_inode(struct inode *inode);
+
+/**
+ * Initialize inode operations on regular files and special files
+ */
+void fuse_init_common(struct inode *inode);
+
+/**
+ * Initialize inode and file operations on a directory
+ */
+void fuse_init_dir(struct inode *inode);
+
+/**
+ * Initialize inode operations on a symlink
+ */
+void fuse_init_symlink(struct inode *inode);
+
+/**
+ * Change attributes of an inode
+ */
+void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr,
+			    u64 attr_valid, u64 attr_version);
+
+void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr,
+				   u64 attr_valid);
+
+/**
+ * Initialize the client device
+ */
+int fuse_dev_init(void);
+
+/**
+ * Cleanup the client device
+ */
+void fuse_dev_cleanup(void);
+
+int fuse_ctl_init(void);
+void __exit fuse_ctl_cleanup(void);
+
+/**
+ * Simple request sending that does request allocation and freeing
+ */
+ssize_t fuse_simple_request(struct fuse_mount *fm, struct fuse_args *args);
+int fuse_simple_background(struct fuse_mount *fm, struct fuse_args *args,
+			   gfp_t gfp_flags);
+
+/**
+ * End a finished request
+ */
+void fuse_request_end(struct fuse_req *req);
+
+/* Abort all requests */
+void fuse_abort_conn(struct fuse_conn *fc);
+void fuse_wait_aborted(struct fuse_conn *fc);
+
+/**
+ * Invalidate inode attributes
+ */
+void fuse_invalidate_attr(struct inode *inode);
+
+void fuse_invalidate_entry_cache(struct dentry *entry);
+
+void fuse_invalidate_atime(struct inode *inode);
+
+u64 entry_attr_timeout(struct fuse_entry_out *o);
+void fuse_change_entry_timeout(struct dentry *entry, struct fuse_entry_out *o);
+
+/**
+ * Acquire reference to fuse_conn
+ */
+struct fuse_conn *fuse_conn_get(struct fuse_conn *fc);
+
+/**
+ * Initialize fuse_conn
+ */
+void fuse_conn_init(struct fuse_conn *fc, struct fuse_mount *fm,
+		    struct user_namespace *user_ns,
+		    const struct fuse_iqueue_ops *fiq_ops, void *fiq_priv);
+
+/**
+ * Release reference to fuse_conn
+ */
+void fuse_conn_put(struct fuse_conn *fc);
+
+/**
+ * Acquire reference to fuse_mount
+ */
+struct fuse_mount *fuse_mount_get(struct fuse_mount *fm);
+
+/**
+ * Release reference to fuse_mount
+ */
+void fuse_mount_put(struct fuse_mount *fm);
+
+struct fuse_dev *fuse_dev_alloc_install(struct fuse_conn *fc);
+struct fuse_dev *fuse_dev_alloc(void);
+void fuse_dev_install(struct fuse_dev *fud, struct fuse_conn *fc);
+void fuse_dev_free(struct fuse_dev *fud);
+void fuse_send_init(struct fuse_mount *fm);
+
+/**
+ * Fill in superblock and initialize fuse connection
+ * @sb: partially-initialized superblock to fill in
+ * @ctx: mount context
+ */
+int fuse_fill_super_common(struct super_block *sb, struct fuse_fs_context *ctx);
+
+/*
+ * Fill in superblock for submounts
+ * @sb: partially-initialized superblock to fill in
+ * @parent_fi: The fuse_inode of the parent filesystem where this submount is
+ * 	       mounted
+ */
+int fuse_fill_super_submount(struct super_block *sb,
+			     struct fuse_inode *parent_fi);
+
+/*
+ * Remove the mount from the connection
+ *
+ * Returns whether this was the last mount
+ */
+bool fuse_mount_remove(struct fuse_mount *fm);
+
+/*
+ * Shut down the connection (possibly sending DESTROY request).
+ */
+void fuse_conn_destroy(struct fuse_mount *fm);
+
+/**
+ * Add connection to control filesystem
+ */
+int fuse_ctl_add_conn(struct fuse_conn *fc);
+
+/**
+ * Remove connection from control filesystem
+ */
+void fuse_ctl_remove_conn(struct fuse_conn *fc);
+
+/**
+ * Is file type valid?
+ */
+int fuse_valid_type(int m);
+
+bool fuse_invalid_attr(struct fuse_attr *attr);
+
+/**
+ * Is current process allowed to perform filesystem operation?
+ */
+int fuse_allow_current_process(struct fuse_conn *fc);
+
+u64 fuse_lock_owner_id(struct fuse_conn *fc, fl_owner_t id);
+
+void fuse_flush_time_update(struct inode *inode);
+void fuse_update_ctime(struct inode *inode);
+
+int fuse_update_attributes(struct inode *inode, struct file *file);
+
+void fuse_flush_writepages(struct inode *inode);
+
+void fuse_set_nowrite(struct inode *inode);
+void fuse_release_nowrite(struct inode *inode);
+
+/**
+ * Scan all fuse_mounts belonging to fc to find the first where
+ * ilookup5() returns a result.  Return that result and the
+ * respective fuse_mount in *fm (unless fm is NULL).
+ *
+ * The caller must hold fc->killsb.
+ */
+struct inode *fuse_ilookup(struct fuse_conn *fc, u64 nodeid,
+			   struct fuse_mount **fm);
+
+/**
+ * File-system tells the kernel to invalidate cache for the given node id.
+ */
+int fuse_reverse_inval_inode(struct fuse_conn *fc, u64 nodeid,
+			     loff_t offset, loff_t len);
+
+/**
+ * File-system tells the kernel to invalidate parent attributes and
+ * the dentry matching parent/name.
+ *
+ * If the child_nodeid is non-zero and:
+ *    - matches the inode number for the dentry matching parent/name,
+ *    - is not a mount point
+ *    - is a file or oan empty directory
+ * then the dentry is unhashed (d_delete()).
+ */
+int fuse_reverse_inval_entry(struct fuse_conn *fc, u64 parent_nodeid,
+			     u64 child_nodeid, struct qstr *name);
+
+int fuse_do_open(struct fuse_mount *fm, u64 nodeid, struct file *file,
+		 bool isdir);
+
+/**
+ * fuse_direct_io() flags
+ */
+
+/** If set, it is WRITE; otherwise - READ */
+#define FUSE_DIO_WRITE (1 << 0)
+
+/** CUSE pass fuse_direct_io() a file which f_mapping->host is not from FUSE */
+#define FUSE_DIO_CUSE  (1 << 1)
+
+ssize_t fuse_direct_io(struct fuse_io_priv *io, struct iov_iter *iter,
+		       loff_t *ppos, int flags);
+long fuse_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg,
+		   unsigned int flags);
+long fuse_ioctl_common(struct file *file, unsigned int cmd,
+		       unsigned long arg, unsigned int flags);
+__poll_t fuse_file_poll(struct file *file, poll_table *wait);
+int fuse_dev_release(struct inode *inode, struct file *file);
+
+bool fuse_write_update_size(struct inode *inode, loff_t pos);
+
+int fuse_flush_times(struct inode *inode, struct fuse_file *ff);
+int fuse_write_inode(struct inode *inode, struct writeback_control *wbc);
+
+int fuse_do_setattr(struct dentry *dentry, struct iattr *attr,
+		    struct file *file);
+
+void fuse_set_initialized(struct fuse_conn *fc);
+
+void fuse_unlock_inode(struct inode *inode, bool locked);
+bool fuse_lock_inode(struct inode *inode);
+
+int fuse_setxattr(struct inode *inode, const char *name, const void *value,
+		  size_t size, int flags);
+ssize_t fuse_getxattr(struct inode *inode, const char *name, void *value,
+		      size_t size);
+ssize_t fuse_listxattr(struct dentry *entry, char *list, size_t size);
+int fuse_removexattr(struct inode *inode, const char *name);
+extern const struct xattr_handler *fuse_xattr_handlers[];
+extern const struct xattr_handler *fuse_acl_xattr_handlers[];
+extern const struct xattr_handler *fuse_no_acl_xattr_handlers[];
+
+struct posix_acl;
+struct posix_acl *fuse_get_acl(struct inode *inode, int type);
+int fuse_set_acl(struct inode *inode, struct posix_acl *acl, int type);
+
+
+/* readdir.c */
+int fuse_readdir(struct file *file, struct dir_context *ctx);
+
+/**
+ * Return the number of bytes in an arguments list
+ */
+unsigned int fuse_len_args(unsigned int numargs, struct fuse_arg *args);
+
+/**
+ * Get the next unique ID for a request
+ */
+u64 fuse_get_unique(struct fuse_iqueue *fiq);
+void fuse_free_conn(struct fuse_conn *fc);
+
+/* dax.c */
+
+#define FUSE_IS_DAX(inode) (IS_ENABLED(CONFIG_FUSE_DAX) && IS_DAX(inode))
+
+ssize_t fuse_dax_read_iter(struct kiocb *iocb, struct iov_iter *to);
+ssize_t fuse_dax_write_iter(struct kiocb *iocb, struct iov_iter *from);
+int fuse_dax_mmap(struct file *file, struct vm_area_struct *vma);
+int fuse_dax_break_layouts(struct inode *inode, u64 dmap_start, u64 dmap_end);
+int fuse_dax_conn_alloc(struct fuse_conn *fc, struct dax_device *dax_dev);
+void fuse_dax_conn_free(struct fuse_conn *fc);
+bool fuse_dax_inode_alloc(struct super_block *sb, struct fuse_inode *fi);
+void fuse_dax_inode_init(struct inode *inode);
+void fuse_dax_inode_cleanup(struct inode *inode);
+bool fuse_dax_check_alignment(struct fuse_conn *fc, unsigned int map_alignment);
+void fuse_dax_cancel_work(struct fuse_conn *fc);
+
+#endif /* _FS_FUSE_I_H */