// SPDX-License-Identifier: LGPL-2.1
/*
 *   CIFS filesystem cache interface
 *
 *   Copyright (c) 2010 Novell, Inc.
 *   Author(s): Suresh Jayaraman <sjayaraman@suse.de>
 *
 */
#include "fscache.h"
#include "cifsglob.h"
#include "cifs_debug.h"
#include "cifs_fs_sb.h"
#include "cifsproto.h"

/*
 * Key for fscache inode.  [!] Contents must match comparisons in cifs_find_inode().
 */
struct cifs_fscache_inode_key {

        __le64  uniqueid;       /* server inode number */
        __le64  createtime;     /* creation time on server */
        u8      type;           /* S_IFMT file type */
} __packed;

static void cifs_fscache_fill_volume_coherency(
        struct cifs_tcon *tcon,
        struct cifs_fscache_volume_coherency_data *cd)
{
        memset(cd, 0, sizeof(*cd));
        cd->resource_id         = cpu_to_le64(tcon->resource_id);
        cd->vol_create_time     = tcon->vol_create_time;
        cd->vol_serial_number   = cpu_to_le32(tcon->vol_serial_number);
}

int cifs_fscache_get_super_cookie(struct cifs_tcon *tcon)
{
        struct cifs_fscache_volume_coherency_data cd;
        struct TCP_Server_Info *server = tcon->ses->server;
        struct fscache_volume *vcookie;
        const struct sockaddr *sa = (struct sockaddr *)&server->dstaddr;
        size_t slen, i;
        char *sharename;
        char *key;
        int ret = -ENOMEM;

        if (tcon->fscache_acquired)
                return 0;

        mutex_lock(&tcon->fscache_lock);
        if (tcon->fscache_acquired) {
                mutex_unlock(&tcon->fscache_lock);
                return 0;
        }
        tcon->fscache_acquired = true;

        tcon->fscache = NULL;
        switch (sa->sa_family) {
        case AF_INET:
        case AF_INET6:
                break;
        default:
                mutex_unlock(&tcon->fscache_lock);
                cifs_dbg(VFS, "Unknown network family '%d'\n", sa->sa_family);
                return -EINVAL;
        }

        memset(&key, 0, sizeof(key));

        sharename = extract_sharename(tcon->tree_name);
        if (IS_ERR(sharename)) {
                mutex_unlock(&tcon->fscache_lock);
                cifs_dbg(FYI, "%s: couldn't extract sharename\n", __func__);
                return PTR_ERR(sharename);
        }

        slen = strlen(sharename);
        for (i = 0; i < slen; i++)
                if (sharename[i] == '/')
                        sharename[i] = ';';

        key = kasprintf(GFP_KERNEL, "cifs,%pISpc,%s", sa, sharename);
        if (!key)
                goto out;

        cifs_fscache_fill_volume_coherency(tcon, &cd);
        vcookie = fscache_acquire_volume(key,
                                         NULL, /* preferred_cache */
                                         &cd, sizeof(cd));
        cifs_dbg(FYI, "%s: (%s/0x%p)\n", __func__, key, vcookie);
        if (IS_ERR(vcookie)) {
                if (vcookie != ERR_PTR(-EBUSY)) {
                        ret = PTR_ERR(vcookie);
                        goto out_2;
                }
                pr_err("Cache volume key already in use (%s)\n", key);
                vcookie = NULL;
                trace_smb3_tcon_ref(tcon->debug_id, tcon->tc_count,
                                    netfs_trace_tcon_ref_see_fscache_collision);
        } else {
                trace_smb3_tcon_ref(tcon->debug_id, tcon->tc_count,
                                    netfs_trace_tcon_ref_see_fscache_okay);
        }

        tcon->fscache = vcookie;
        ret = 0;
out_2:
        kfree(key);
out:
        kfree(sharename);
        mutex_unlock(&tcon->fscache_lock);
        return ret;
}

void cifs_fscache_release_super_cookie(struct cifs_tcon *tcon)
{
        struct cifs_fscache_volume_coherency_data cd;

        cifs_dbg(FYI, "%s: (0x%p)\n", __func__, tcon->fscache);

        cifs_fscache_fill_volume_coherency(tcon, &cd);
        fscache_relinquish_volume(tcon->fscache, &cd, false);
        tcon->fscache = NULL;
        trace_smb3_tcon_ref(tcon->debug_id, tcon->tc_count,
                            netfs_trace_tcon_ref_see_fscache_relinq);
}

void cifs_fscache_get_inode_cookie(struct inode *inode)
{
        struct cifs_fscache_inode_coherency_data cd;
        struct cifs_fscache_inode_key key;
        struct cifsInodeInfo *cifsi = CIFS_I(inode);
        struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
        struct cifs_tcon *tcon = cifs_sb_master_tcon(cifs_sb);

        key.uniqueid    = cpu_to_le64(cifsi->uniqueid);
        key.createtime  = cpu_to_le64(cifsi->createtime);
        key.type        = (inode->i_mode & S_IFMT) >> 12;
        cifs_fscache_fill_coherency(&cifsi->netfs.inode, &cd);

        cifsi->netfs.cache =
                fscache_acquire_cookie(tcon->fscache, 0,
                                       &key, sizeof(key),
                                       &cd, sizeof(cd),
                                       i_size_read(&cifsi->netfs.inode));
        if (cifsi->netfs.cache)
                mapping_set_release_always(inode->i_mapping);
}

void cifs_fscache_unuse_inode_cookie(struct inode *inode, bool update)
{
        if (update) {
                struct cifs_fscache_inode_coherency_data cd;
                loff_t i_size = i_size_read(inode);

                cifs_fscache_fill_coherency(inode, &cd);
                fscache_unuse_cookie(cifs_inode_cookie(inode), &cd, &i_size);
        } else {
                fscache_unuse_cookie(cifs_inode_cookie(inode), NULL, NULL);
        }
}

void cifs_fscache_release_inode_cookie(struct inode *inode)
{
        struct cifsInodeInfo *cifsi = CIFS_I(inode);
        struct fscache_cookie *cookie = cifs_inode_cookie(inode);

        if (cookie) {
                cifs_dbg(FYI, "%s: (0x%p)\n", __func__, cookie);
                fscache_relinquish_cookie(cookie, false);
                cifsi->netfs.cache = NULL;
        }
}