/* SPDX-License-Identifier: GPL-2.0 */
/*
 *  Functions to handle the cached directory entries
 *
 *  Copyright (c) 2022, Ronnie Sahlberg <lsahlber@redhat.com>
 */

#ifndef _CACHED_DIR_H
#define _CACHED_DIR_H


struct cached_dirent {
        struct list_head entry;
        char *name;
        int namelen;
        loff_t pos;
        struct cifs_fattr fattr;
};

struct cached_dirents {
        bool is_valid:1;
        bool is_failed:1;
        struct file *file; /*
                            * Used to associate the cache with a single
                            * open file instance.
                            */
        struct mutex de_mutex;
        loff_t pos;              /* Expected ctx->pos */
        struct list_head entries;
        /* accounting for cached entries in this directory */
        unsigned long entries_count;
        unsigned long bytes_used;
};

struct cached_fid {
        struct list_head entry;
        struct cached_fids *cfids;
        const char *path;
        bool has_lease;
        bool is_open;
        bool on_list;
        bool file_all_info_is_valid;
        unsigned long time; /* jiffies of when lease was taken */
        unsigned long last_access_time; /* jiffies of when last accessed */
        struct kref refcount;
        struct cifs_fid fid;
        struct cifs_tcon *tcon;
        struct dentry *dentry;
        struct work_struct put_work;
        struct work_struct close_work;
        struct cached_dirents dirents;

        /* Must be last as it ends in a flexible-array member. */
        struct smb2_file_all_info file_all_info;
};

/* default MAX_CACHED_FIDS is 16 */
struct cached_fids {
        /* Must be held when:
         * - accessing the cfids->entries list
         * - accessing the cfids->dying list
         */
        spinlock_t cfid_list_lock;
        int num_entries;
        struct list_head entries;
        struct list_head dying;
        struct delayed_work laundromat_work;
        /* aggregate accounting for all cached dirents under this tcon */
        atomic_long_t total_dirents_entries;
        atomic64_t total_dirents_bytes;
};

/* Module-wide directory cache accounting (defined in cifsfs.c) */
extern atomic64_t cifs_dircache_bytes_used; /* bytes across all mounts */

static inline bool
is_valid_cached_dir(struct cached_fid *cfid)
{
        return cfid->time && cfid->has_lease;
}

struct cached_fids *init_cached_dirs(void);
void free_cached_dirs(struct cached_fids *cfids);
int open_cached_dir(unsigned int xid, struct cifs_tcon *tcon, const char *path,
                    struct cifs_sb_info *cifs_sb, bool lookup_only,
                    struct cached_fid **ret_cfid);
int open_cached_dir_by_dentry(struct cifs_tcon *tcon, struct dentry *dentry,
                              struct cached_fid **ret_cfid);
void close_cached_dir(struct cached_fid *cfid);
void drop_cached_dir_by_name(const unsigned int xid, struct cifs_tcon *tcon,
                             const char *name, struct cifs_sb_info *cifs_sb);
void close_all_cached_dirs(struct cifs_sb_info *cifs_sb);
void invalidate_all_cached_dirs(struct cifs_tcon *tcon);
bool cached_dir_lease_break(struct cifs_tcon *tcon, __u8 lease_key[16]);

#endif                  /* _CACHED_DIR_H */