/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _FS_CEPH_MDS_CLIENT_H
#define _FS_CEPH_MDS_CLIENT_H

#include <linux/completion.h>
#include <linux/kref.h>
#include <linux/list.h>
#include <linux/mutex.h>
#include <linux/rbtree.h>
#include <linux/spinlock.h>
#include <linux/refcount.h>
#include <linux/utsname.h>
#include <linux/ktime.h>

#include <linux/ceph/types.h>
#include <linux/ceph/messenger.h>
#include <linux/ceph/auth.h>

#include "mdsmap.h"
#include "metric.h"
#include "super.h"

/* The first 8 bits are reserved for old ceph releases */
enum ceph_feature_type {
        CEPHFS_FEATURE_MIMIC = 8,
        CEPHFS_FEATURE_REPLY_ENCODING,
        CEPHFS_FEATURE_RECLAIM_CLIENT,
        CEPHFS_FEATURE_LAZY_CAP_WANTED,
        CEPHFS_FEATURE_MULTI_RECONNECT,
        CEPHFS_FEATURE_DELEG_INO,
        CEPHFS_FEATURE_METRIC_COLLECT,
        CEPHFS_FEATURE_ALTERNATE_NAME,
        CEPHFS_FEATURE_NOTIFY_SESSION_STATE,
        CEPHFS_FEATURE_OP_GETVXATTR,
        CEPHFS_FEATURE_32BITS_RETRY_FWD,
        CEPHFS_FEATURE_NEW_SNAPREALM_INFO,
        CEPHFS_FEATURE_HAS_OWNER_UIDGID,
        CEPHFS_FEATURE_MDS_AUTH_CAPS_CHECK,

        CEPHFS_FEATURE_MAX = CEPHFS_FEATURE_MDS_AUTH_CAPS_CHECK,
};

#define CEPHFS_FEATURES_CLIENT_SUPPORTED {      \
        0, 1, 2, 3, 4, 5, 6, 7,                 \
        CEPHFS_FEATURE_MIMIC,                   \
        CEPHFS_FEATURE_REPLY_ENCODING,          \
        CEPHFS_FEATURE_LAZY_CAP_WANTED,         \
        CEPHFS_FEATURE_MULTI_RECONNECT,         \
        CEPHFS_FEATURE_DELEG_INO,               \
        CEPHFS_FEATURE_METRIC_COLLECT,          \
        CEPHFS_FEATURE_ALTERNATE_NAME,          \
        CEPHFS_FEATURE_NOTIFY_SESSION_STATE,    \
        CEPHFS_FEATURE_OP_GETVXATTR,            \
        CEPHFS_FEATURE_32BITS_RETRY_FWD,        \
        CEPHFS_FEATURE_HAS_OWNER_UIDGID,        \
        CEPHFS_FEATURE_MDS_AUTH_CAPS_CHECK,     \
}

/*
 * Some lock dependencies:
 *
 * session->s_mutex
 *         mdsc->mutex
 *
 *         mdsc->snap_rwsem
 *
 *         ci->i_ceph_lock
 *                 mdsc->snap_flush_lock
 *                 mdsc->cap_delay_lock
 *
 */

struct ceph_fs_client;
struct ceph_cap;

#define MDS_AUTH_UID_ANY -1

struct ceph_mds_cap_match {
        s64 uid;  /* default to MDS_AUTH_UID_ANY */
        u32 num_gids;
        u32 *gids;  /* use these GIDs */
        char *path;  /* require path to be child of this
                        (may be "" or "/" for any) */
        char *fs_name;
        bool root_squash;  /* default to false */
};

struct ceph_mds_cap_auth {
        struct ceph_mds_cap_match match;
        bool readable;
        bool writeable;
};

/*
 * parsed info about a single inode.  pointers are into the encoded
 * on-wire structures within the mds reply message payload.
 */
struct ceph_mds_reply_info_in {
        struct ceph_mds_reply_inode *in;
        struct ceph_dir_layout dir_layout;
        u32 symlink_len;
        char *symlink;
        u32 xattr_len;
        char *xattr_data;
        u64 inline_version;
        u32 inline_len;
        char *inline_data;
        u32 pool_ns_len;
        char *pool_ns_data;
        u64 max_bytes;
        u64 max_files;
        s32 dir_pin;
        struct ceph_timespec btime;
        struct ceph_timespec snap_btime;
        u8 *fscrypt_auth;
        u8 *fscrypt_file;
        u32 fscrypt_auth_len;
        u32 fscrypt_file_len;
        u64 rsnaps;
        u64 change_attr;
};

struct ceph_mds_reply_dir_entry {
        bool                          is_nokey;
        char                          *name;
        u32                           name_len;
        u32                           raw_hash;
        struct ceph_mds_reply_lease   *lease;
        struct ceph_mds_reply_info_in inode;
        loff_t                        offset;
};

struct ceph_mds_reply_xattr {
        char *xattr_value;
        size_t xattr_value_len;
};

/*
 * parsed info about an mds reply, including information about
 * either: 1) the target inode and/or its parent directory and dentry,
 * and directory contents (for readdir results), or
 * 2) the file range lock info (for fcntl F_GETLK results).
 */
struct ceph_mds_reply_info_parsed {
        struct ceph_mds_reply_head    *head;

        /* trace */
        struct ceph_mds_reply_info_in diri, targeti;
        struct ceph_mds_reply_dirfrag *dirfrag;
        char                          *dname;
        u8                            *altname;
        u32                           dname_len;
        u32                           altname_len;
        struct ceph_mds_reply_lease   *dlease;
        struct ceph_mds_reply_xattr   xattr_info;

        /* extra */
        union {
                /* for fcntl F_GETLK results */
                struct ceph_filelock *filelock_reply;

                /* for readdir results */
                struct {
                        struct ceph_mds_reply_dirfrag *dir_dir;
                        size_t                        dir_buf_size;
                        int                           dir_nr;
                        bool                          dir_end;
                        bool                          dir_complete;
                        bool                          hash_order;
                        bool                          offset_hash;
                        struct ceph_mds_reply_dir_entry  *dir_entries;
                };

                /* for create results */
                struct {
                        bool has_create_ino;
                        u64 ino;
                };
        };

        /* encoded blob describing snapshot contexts for certain
           operations (e.g., open) */
        void *snapblob;
        int snapblob_len;
};


/*
 * cap releases are batched and sent to the MDS en masse.
 *
 * Account for per-message overhead of mds_cap_release header
 * and __le32 for osd epoch barrier trailing field.
 */
#define CEPH_CAPS_PER_RELEASE ((PAGE_SIZE - sizeof(u32) -               \
                                sizeof(struct ceph_mds_cap_release)) /  \
                                sizeof(struct ceph_mds_cap_item))


/*
 * state associated with each MDS<->client session
 */
enum {
        CEPH_MDS_SESSION_NEW = 1,
        CEPH_MDS_SESSION_OPENING = 2,
        CEPH_MDS_SESSION_OPEN = 3,
        CEPH_MDS_SESSION_HUNG = 4,
        CEPH_MDS_SESSION_RESTARTING = 5,
        CEPH_MDS_SESSION_RECONNECTING = 6,
        CEPH_MDS_SESSION_CLOSING = 7,
        CEPH_MDS_SESSION_CLOSED = 8,
        CEPH_MDS_SESSION_REJECTED = 9,
};

struct ceph_mds_session {
        struct ceph_mds_client *s_mdsc;
        int               s_mds;
        int               s_state;
        unsigned long     s_ttl;      /* time until mds kills us */
        unsigned long     s_features;
        u64               s_seq;      /* incoming msg seq # */
        struct mutex      s_mutex;    /* serialize session messages */

        struct ceph_connection s_con;

        struct ceph_auth_handshake s_auth;

        atomic_t          s_cap_gen;  /* inc each time we get mds stale msg */
        unsigned long     s_cap_ttl;  /* when session caps expire. protected by s_mutex */

        /* protected by s_cap_lock */
        spinlock_t        s_cap_lock;
        refcount_t        s_ref;
        struct list_head  s_caps;     /* all caps issued by this session */
        struct ceph_cap  *s_cap_iterator;
        int               s_nr_caps;
        int               s_num_cap_releases;
        int               s_cap_reconnect;
        int               s_readonly;
        struct list_head  s_cap_releases; /* waiting cap_release messages */
        struct work_struct s_cap_release_work;

        /* See ceph_inode_info->i_dirty_item. */
        struct list_head  s_cap_dirty;        /* inodes w/ dirty caps */

        /* See ceph_inode_info->i_flushing_item. */
        struct list_head  s_cap_flushing;     /* inodes w/ flushing caps */

        unsigned long     s_renew_requested; /* last time we sent a renew req */
        u64               s_renew_seq;

        struct list_head  s_waiting;  /* waiting requests */
        struct list_head  s_unsafe;   /* unsafe requests */
        struct xarray     s_delegated_inos;
};

/*
 * modes of choosing which MDS to send a request to
 */
enum {
        USE_ANY_MDS,
        USE_RANDOM_MDS,
        USE_AUTH_MDS,   /* prefer authoritative mds for this metadata item */
};

struct ceph_mds_request;
struct ceph_mds_client;

/*
 * request completion callback
 */
typedef void (*ceph_mds_request_callback_t) (struct ceph_mds_client *mdsc,
                                             struct ceph_mds_request *req);
/*
 * wait for request completion callback
 */
typedef int (*ceph_mds_request_wait_callback_t) (struct ceph_mds_client *mdsc,
                                                 struct ceph_mds_request *req);

/*
 * an in-flight mds request
 */
struct ceph_mds_request {
        u64 r_tid;                   /* transaction id */
        struct rb_node r_node;
        struct ceph_mds_client *r_mdsc;

        struct kref       r_kref;
        int r_op;                    /* mds op code */

        /* operation on what? */
        struct inode *r_inode;              /* arg1 */
        struct dentry *r_dentry;            /* arg1 */
        struct dentry *r_old_dentry;        /* arg2: rename from or link from */
        struct inode *r_old_dentry_dir;     /* arg2: old dentry's parent dir */
        char *r_path1, *r_path2;
        struct ceph_vino r_ino1, r_ino2;

        struct inode *r_parent;             /* parent dir inode */
        struct inode *r_target_inode;       /* resulting inode */
        struct inode *r_new_inode;          /* new inode (for creates) */

        const struct qstr *r_dname;         /* stable name (for ->d_revalidate) */

#define CEPH_MDS_R_DIRECT_IS_HASH       (1) /* r_direct_hash is valid */
#define CEPH_MDS_R_ABORTED              (2) /* call was aborted */
#define CEPH_MDS_R_GOT_UNSAFE           (3) /* got an unsafe reply */
#define CEPH_MDS_R_GOT_SAFE             (4) /* got a safe reply */
#define CEPH_MDS_R_GOT_RESULT           (5) /* got a result */
#define CEPH_MDS_R_DID_PREPOPULATE      (6) /* prepopulated readdir */
#define CEPH_MDS_R_PARENT_LOCKED        (7) /* is r_parent->i_rwsem wlocked? */
#define CEPH_MDS_R_ASYNC                (8) /* async request */
#define CEPH_MDS_R_FSCRYPT_FILE         (9) /* must marshal fscrypt_file field */
        unsigned long   r_req_flags;

        struct mutex r_fill_mutex;

        union ceph_mds_request_args r_args;

        struct ceph_fscrypt_auth *r_fscrypt_auth;
        u64     r_fscrypt_file;

        u8 *r_altname;              /* fscrypt binary crypttext for long filenames */
        u32 r_altname_len;          /* length of r_altname */

        int r_fmode;        /* file mode, if expecting cap */
        int r_request_release_offset;
        const struct cred *r_cred;
        struct mnt_idmap *r_mnt_idmap;
        struct timespec64 r_stamp;

        /* for choosing which mds to send this request to */
        int r_direct_mode;
        u32 r_direct_hash;      /* choose dir frag based on this dentry hash */

        /* data payload is used for xattr ops */
        struct ceph_pagelist *r_pagelist;

        /* what caps shall we drop? */
        int r_inode_drop, r_inode_unless;
        int r_dentry_drop, r_dentry_unless;
        int r_old_dentry_drop, r_old_dentry_unless;
        struct inode *r_old_inode;
        int r_old_inode_drop, r_old_inode_unless;

        struct ceph_msg  *r_request;  /* original request */
        struct ceph_msg  *r_reply;
        struct ceph_mds_reply_info_parsed r_reply_info;
        int r_err;
        u32               r_readdir_offset;

        struct page *r_locked_page;
        int r_dir_caps;
        int r_num_caps;

        unsigned long r_timeout;  /* optional.  jiffies, 0 is "wait forever" */
        unsigned long r_started;  /* start time to measure timeout against */
        unsigned long r_start_latency;  /* start time to measure latency */
        unsigned long r_end_latency;    /* finish time to measure latency */
        unsigned long r_request_started; /* start time for mds request only,
                                            used to measure lease durations */

        /* link unsafe requests to parent directory, for fsync */
        struct inode    *r_unsafe_dir;
        struct list_head r_unsafe_dir_item;

        /* unsafe requests that modify the target inode */
        struct list_head r_unsafe_target_item;

        struct ceph_mds_session *r_session;

        int               r_attempts;   /* resend attempts */
        int               r_num_fwd;    /* number of forward attempts */
        int               r_resend_mds; /* mds to resend to next, if any*/
        u32               r_sent_on_mseq; /* cap mseq request was sent at*/
        u64               r_deleg_ino;

        struct list_head  r_wait;
        struct completion r_completion;
        struct completion r_safe_completion;
        ceph_mds_request_callback_t r_callback;
        struct list_head  r_unsafe_item;  /* per-session unsafe list item */

        long long         r_dir_release_cnt;
        long long         r_dir_ordered_cnt;
        int               r_readdir_cache_idx;

        int               r_feature_needed;

        struct ceph_cap_reservation r_caps_reservation;
};

struct ceph_pool_perm {
        struct rb_node node;
        int perm;
        s64 pool;
        size_t pool_ns_len;
        char pool_ns[];
};

struct ceph_snapid_map {
        struct rb_node node;
        struct list_head lru;
        atomic_t ref;
        dev_t dev;
        u64 snap;
        unsigned long last_used;
};

/*
 * node for list of quotarealm inodes that are not visible from the filesystem
 * mountpoint, but required to handle, e.g. quotas.
 */
struct ceph_quotarealm_inode {
        struct rb_node node;
        u64 ino;
        unsigned long timeout; /* last time a lookup failed for this inode */
        struct mutex mutex;
        struct inode *inode;
};

#ifdef CONFIG_DEBUG_FS

struct cap_wait {
        struct list_head        list;
        u64                     ino;
        pid_t                   tgid;
        int                     need;
        int                     want;
};

#endif

enum {
        CEPH_MDSC_STOPPING_BEGIN = 1,
        CEPH_MDSC_STOPPING_FLUSHING = 2,
        CEPH_MDSC_STOPPING_FLUSHED = 3,
};

/*
 * mds client state
 */
struct ceph_mds_client {
        struct ceph_fs_client  *fsc;
        struct mutex            mutex;         /* all nested structures */

        struct ceph_mdsmap      *mdsmap;
        struct completion       safe_umount_waiters;
        wait_queue_head_t       session_close_wq;
        struct list_head        waiting_for_map;
        int                     mdsmap_err;

        struct ceph_mds_session **sessions;    /* NULL for mds if no session */
        atomic_t                num_sessions;
        int                     max_sessions;  /* len of sessions array */

        spinlock_t              stopping_lock;  /* protect snap_empty */
        int                     stopping;      /* the stage of shutting down */
        atomic_t                stopping_blockers;
        struct completion       stopping_waiter;

        atomic64_t              dirty_folios;
        wait_queue_head_t       flush_end_wq;

        atomic64_t              quotarealms_count; /* # realms with quota */
        /*
         * We keep a list of inodes we don't see in the mountpoint but that we
         * need to track quota realms.
         */
        struct rb_root          quotarealms_inodes;
        struct mutex            quotarealms_inodes_mutex;

        /*
         * snap_rwsem will cover cap linkage into snaprealms, and
         * realm snap contexts.  (later, we can do per-realm snap
         * contexts locks..)  the empty list contains realms with no
         * references (implying they contain no inodes with caps) that
         * should be destroyed.
         */
        u64                     last_snap_seq;
        struct rw_semaphore     snap_rwsem;
        struct rb_root          snap_realms;
        struct list_head        snap_empty;
        int                     num_snap_realms;
        spinlock_t              snap_empty_lock;  /* protect snap_empty */

        u64                    last_tid;      /* most recent mds request */
        u64                    oldest_tid;    /* oldest incomplete mds request,
                                                 excluding setfilelock requests */
        struct rb_root         request_tree;  /* pending mds requests */
        struct delayed_work    delayed_work;  /* delayed work */
        unsigned long    last_renew_caps;  /* last time we renewed our caps */
        struct list_head cap_delay_list;   /* caps with delayed release */
        struct list_head cap_unlink_delay_list;  /* caps with delayed release for unlink */
        spinlock_t       cap_delay_lock;   /* protects cap_delay_list and cap_unlink_delay_list */
        struct list_head snap_flush_list;  /* cap_snaps ready to flush */
        spinlock_t       snap_flush_lock;

        u64               last_cap_flush_tid;
        struct list_head  cap_flush_list;
        struct list_head  cap_dirty_migrating; /* ...that are migration... */
        int               num_cap_flushing; /* # caps we are flushing */
        spinlock_t        cap_dirty_lock;   /* protects above items */
        wait_queue_head_t cap_flushing_wq;

        struct work_struct cap_reclaim_work;
        atomic_t           cap_reclaim_pending;

        struct work_struct cap_unlink_work;

        /*
         * Cap reservations
         *
         * Maintain a global pool of preallocated struct ceph_caps, referenced
         * by struct ceph_caps_reservations.  This ensures that we preallocate
         * memory needed to successfully process an MDS response.  (If an MDS
         * sends us cap information and we fail to process it, we will have
         * problems due to the client and MDS being out of sync.)
         *
         * Reservations are 'owned' by a ceph_cap_reservation context.
         */
        spinlock_t      caps_list_lock;
        struct          list_head caps_list; /* unused (reserved or
                                                unreserved) */
#ifdef CONFIG_DEBUG_FS
        struct          list_head cap_wait_list;
#endif
        int             caps_total_count;    /* total caps allocated */
        int             caps_use_count;      /* in use */
        int             caps_use_max;        /* max used caps */
        int             caps_reserve_count;  /* unused, reserved */
        int             caps_avail_count;    /* unused, unreserved */
        int             caps_min_count;      /* keep at least this many
                                                (unreserved) */
        spinlock_t        dentry_list_lock;
        struct list_head  dentry_leases;     /* fifo list */
        struct list_head  dentry_dir_leases; /* lru list */

        struct ceph_client_metric metric;

        spinlock_t              snapid_map_lock;
        struct rb_root          snapid_map_tree;
        struct list_head        snapid_map_lru;

        struct rw_semaphore     pool_perm_rwsem;
        struct rb_root          pool_perm_tree;

        u32                      s_cap_auths_num;
        struct ceph_mds_cap_auth *s_cap_auths;

        char nodename[__NEW_UTS_LEN + 1];
};

extern const char *ceph_mds_op_name(int op);

extern bool check_session_state(struct ceph_mds_session *s);
void inc_session_sequence(struct ceph_mds_session *s);

extern struct ceph_mds_session *
__ceph_lookup_mds_session(struct ceph_mds_client *, int mds);

extern const char *ceph_session_state_name(int s);

extern struct ceph_mds_session *
ceph_get_mds_session(struct ceph_mds_session *s);
extern void ceph_put_mds_session(struct ceph_mds_session *s);

extern int ceph_mdsc_init(struct ceph_fs_client *fsc);
extern void ceph_mdsc_close_sessions(struct ceph_mds_client *mdsc);
extern void ceph_mdsc_force_umount(struct ceph_mds_client *mdsc);
extern void ceph_mdsc_destroy(struct ceph_fs_client *fsc);

extern void ceph_mdsc_sync(struct ceph_mds_client *mdsc);

extern void ceph_invalidate_dir_request(struct ceph_mds_request *req);
extern int ceph_alloc_readdir_reply_buffer(struct ceph_mds_request *req,
                                           struct inode *dir);
extern struct ceph_mds_request *
ceph_mdsc_create_request(struct ceph_mds_client *mdsc, int op, int mode);
extern int ceph_mdsc_submit_request(struct ceph_mds_client *mdsc,
                                    struct inode *dir,
                                    struct ceph_mds_request *req);
int ceph_mdsc_wait_request(struct ceph_mds_client *mdsc,
                        struct ceph_mds_request *req,
                        ceph_mds_request_wait_callback_t wait_func);
extern int ceph_mdsc_do_request(struct ceph_mds_client *mdsc,
                                struct inode *dir,
                                struct ceph_mds_request *req);
extern void ceph_mdsc_release_dir_caps(struct ceph_mds_request *req);
extern void ceph_mdsc_release_dir_caps_async(struct ceph_mds_request *req);
static inline void ceph_mdsc_get_request(struct ceph_mds_request *req)
{
        kref_get(&req->r_kref);
}
extern void ceph_mdsc_release_request(struct kref *kref);
static inline void ceph_mdsc_put_request(struct ceph_mds_request *req)
{
        kref_put(&req->r_kref, ceph_mdsc_release_request);
}

extern void send_flush_mdlog(struct ceph_mds_session *s);
extern void ceph_mdsc_iterate_sessions(struct ceph_mds_client *mdsc,
                                       void (*cb)(struct ceph_mds_session *),
                                       bool check_state);
extern struct ceph_msg *ceph_create_session_msg(u32 op, u64 seq);
extern void __ceph_queue_cap_release(struct ceph_mds_session *session,
                                    struct ceph_cap *cap);
extern void ceph_flush_session_cap_releases(struct ceph_mds_client *mdsc,
                                            struct ceph_mds_session *session);
extern void ceph_queue_cap_reclaim_work(struct ceph_mds_client *mdsc);
extern void ceph_reclaim_caps_nr(struct ceph_mds_client *mdsc, int nr);
extern void ceph_queue_cap_unlink_work(struct ceph_mds_client *mdsc);
extern int ceph_iterate_session_caps(struct ceph_mds_session *session,
                                     int (*cb)(struct inode *, int mds, void *),
                                     void *arg);
extern int ceph_mds_check_access(struct ceph_mds_client *mdsc, char *tpath,
                                 int mask);

extern void ceph_mdsc_pre_umount(struct ceph_mds_client *mdsc);

/*
 * Structure to group path-related output parameters for build_*_path functions
 */
struct ceph_path_info {
        const char *path;
        int pathlen;
        struct ceph_vino vino;
        bool freepath;
};

static inline void ceph_mdsc_free_path_info(const struct ceph_path_info *path_info)
{
        if (path_info && path_info->freepath && !IS_ERR_OR_NULL(path_info->path))
                __putname((char *)path_info->path - (PATH_MAX - 1 - path_info->pathlen));
}

extern char *ceph_mdsc_build_path(struct ceph_mds_client *mdsc,
                                  struct dentry *dentry, struct ceph_path_info *path_info,
                                  int for_wire);

extern void __ceph_mdsc_drop_dentry_lease(struct dentry *dentry);
extern void ceph_mdsc_lease_send_msg(struct ceph_mds_session *session,
                                     struct dentry *dentry, char action,
                                     u32 seq);

extern void ceph_mdsc_handle_mdsmap(struct ceph_mds_client *mdsc,
                                    struct ceph_msg *msg);
extern void ceph_mdsc_handle_fsmap(struct ceph_mds_client *mdsc,
                                   struct ceph_msg *msg);

extern struct ceph_mds_session *
ceph_mdsc_open_export_target_session(struct ceph_mds_client *mdsc, int target);

extern int ceph_trim_caps(struct ceph_mds_client *mdsc,
                          struct ceph_mds_session *session,
                          int max_caps);

static inline int ceph_wait_on_async_create(struct inode *inode)
{
        struct ceph_inode_info *ci = ceph_inode(inode);

        return wait_on_bit(&ci->i_ceph_flags, CEPH_ASYNC_CREATE_BIT,
                           TASK_KILLABLE);
}

extern int ceph_wait_on_conflict_unlink(struct dentry *dentry);
extern u64 ceph_get_deleg_ino(struct ceph_mds_session *session);
extern int ceph_restore_deleg_ino(struct ceph_mds_session *session, u64 ino);

extern bool enable_unsafe_idmap;
#endif