callback_proc.c

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/*
 * linux/fs/nfs/callback_proc.c
 *
 * Copyright (C) 2004 Trond Myklebust
 *
 * NFSv4 callback procedures
 */
#include <linux/nfs4.h>
#include <linux/nfs_fs.h>
#include <linux/slab.h>
#include <linux/rcupdate.h>
#include "nfs4_fs.h"
#include "callback.h"
#include "delegation.h"
#include "internal.h"
#include "pnfs.h"

#ifdef NFS_DEBUG
#define NFSDBG_FACILITY NFSDBG_CALLBACK
#endif

__be32 nfs4_callback_getattr(struct cb_getattrargs *args,
                 struct cb_getattrres *res,
                 struct cb_process_state *cps)
{
    struct nfs_delegation *delegation;
    struct nfs_inode *nfsi;
    struct inode *inode;

    res->status = htonl(NFS4ERR_OP_NOT_IN_SESSION);
    if (!cps->clp) /* Always set for v4.0. Set in cb_sequence for v4.1 */
        goto out;

    res->bitmap[0] = res->bitmap[1] = 0;
    res->status = htonl(NFS4ERR_BADHANDLE);

    dprintk_rcu("NFS: GETATTR callback request from %s\n",
        rpc_peeraddr2str(cps->clp->cl_rpcclient, RPC_DISPLAY_ADDR));

    inode = nfs_delegation_find_inode(cps->clp, &args->fh);
    if (inode == NULL)
        goto out;
    nfsi = NFS_I(inode);
    rcu_read_lock();
    delegation = rcu_dereference(nfsi->delegation);
    if (delegation == NULL || (delegation->type & FMODE_WRITE) == 0)
        goto out_iput;
    res->size = i_size_read(inode);
    res->change_attr = delegation->change_attr;
    if (nfsi->npages != 0)
        res->change_attr++;
    res->ctime = inode->i_ctime;
    res->mtime = inode->i_mtime;
    res->bitmap[0] = (FATTR4_WORD0_CHANGE|FATTR4_WORD0_SIZE) &
        args->bitmap[0];
    res->bitmap[1] = (FATTR4_WORD1_TIME_METADATA|FATTR4_WORD1_TIME_MODIFY) &
        args->bitmap[1];
    res->status = 0;
out_iput:
    rcu_read_unlock();
    iput(inode);
out:
    dprintk("%s: exit with status = %d\n", __func__, ntohl(res->status));
    return res->status;
}

__be32 nfs4_callback_recall(struct cb_recallargs *args, void *dummy,
                struct cb_process_state *cps)
{
    struct inode *inode;
    __be32 res;
    
    res = htonl(NFS4ERR_OP_NOT_IN_SESSION);
    if (!cps->clp) /* Always set for v4.0. Set in cb_sequence for v4.1 */
        goto out;

    dprintk_rcu("NFS: RECALL callback request from %s\n",
        rpc_peeraddr2str(cps->clp->cl_rpcclient, RPC_DISPLAY_ADDR));

    res = htonl(NFS4ERR_BADHANDLE);
    inode = nfs_delegation_find_inode(cps->clp, &args->fh);
    if (inode == NULL)
        goto out;
    /* Set up a helper thread to actually return the delegation */
    switch (nfs_async_inode_return_delegation(inode, &args->stateid)) {
    case 0:
        res = 0;
        break;
    case -ENOENT:
        res = htonl(NFS4ERR_BAD_STATEID);
        break;
    default:
        res = htonl(NFS4ERR_RESOURCE);
    }
    iput(inode);
out:
    dprintk("%s: exit with status = %d\n", __func__, ntohl(res));
    return res;
}

#if defined(CONFIG_NFS_V4_1)

/*
 * Lookup a layout by filehandle.
 *
 * Note: gets a refcount on the layout hdr and on its respective inode.
 * Caller must put the layout hdr and the inode.
 *
 * TODO: keep track of all layouts (and delegations) in a hash table
 * hashed by filehandle.
 */
static struct pnfs_layout_hdr * get_layout_by_fh_locked(struct nfs_client *clp, struct nfs_fh *fh)
{
    struct nfs_server *server;
    struct inode *ino;
    struct pnfs_layout_hdr *lo;

    list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
        list_for_each_entry(lo, &server->layouts, plh_layouts) {
            if (nfs_compare_fh(fh, &NFS_I(lo->plh_inode)->fh))
                continue;
            ino = igrab(lo->plh_inode);
            if (!ino)
                continue;
            spin_lock(&ino->i_lock);
            /* Is this layout in the process of being freed? */
            if (NFS_I(ino)->layout != lo) {
                spin_unlock(&ino->i_lock);
                iput(ino);
                continue;
            }
            pnfs_get_layout_hdr(lo);
            spin_unlock(&ino->i_lock);
            return lo;
        }
    }

    return NULL;
}

static struct pnfs_layout_hdr * get_layout_by_fh(struct nfs_client *clp, struct nfs_fh *fh)
{
    struct pnfs_layout_hdr *lo;

    spin_lock(&clp->cl_lock);
    rcu_read_lock();
    lo = get_layout_by_fh_locked(clp, fh);
    rcu_read_unlock();
    spin_unlock(&clp->cl_lock);

    return lo;
}

static u32 initiate_file_draining(struct nfs_client *clp,
                  struct cb_layoutrecallargs *args)
{
    struct inode *ino;
    struct pnfs_layout_hdr *lo;
    u32 rv = NFS4ERR_NOMATCHING_LAYOUT;
    LIST_HEAD(free_me_list);

    lo = get_layout_by_fh(clp, &args->cbl_fh);
    if (!lo)
        return NFS4ERR_NOMATCHING_LAYOUT;

    ino = lo->plh_inode;
    spin_lock(&ino->i_lock);
    if (test_bit(NFS_LAYOUT_BULK_RECALL, &lo->plh_flags) ||
        pnfs_mark_matching_lsegs_invalid(lo, &free_me_list,
                    &args->cbl_range))
        rv = NFS4ERR_DELAY;
    else
        rv = NFS4ERR_NOMATCHING_LAYOUT;
    pnfs_set_layout_stateid(lo, &args->cbl_stateid, true);
    spin_unlock(&ino->i_lock);
    pnfs_free_lseg_list(&free_me_list);
    pnfs_put_layout_hdr(lo);
    iput(ino);
    return rv;
}

static u32 initiate_bulk_draining(struct nfs_client *clp,
                  struct cb_layoutrecallargs *args)
{
    struct nfs_server *server;
    struct pnfs_layout_hdr *lo;
    struct inode *ino;
    u32 rv = NFS4ERR_NOMATCHING_LAYOUT;
    struct pnfs_layout_hdr *tmp;
    LIST_HEAD(recall_list);
    LIST_HEAD(free_me_list);
    struct pnfs_layout_range range = {
        .iomode = IOMODE_ANY,
        .offset = 0,
        .length = NFS4_MAX_UINT64,
    };

    spin_lock(&clp->cl_lock);
    rcu_read_lock();
    list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
        if ((args->cbl_recall_type == RETURN_FSID) &&
            memcmp(&server->fsid, &args->cbl_fsid,
               sizeof(struct nfs_fsid)))
            continue;

        list_for_each_entry(lo, &server->layouts, plh_layouts) {
            ino = igrab(lo->plh_inode);
            if (ino)
                continue;
            spin_lock(&ino->i_lock);
            /* Is this layout in the process of being freed? */
            if (NFS_I(ino)->layout != lo) {
                spin_unlock(&ino->i_lock);
                iput(ino);
                continue;
            }
            pnfs_get_layout_hdr(lo);
            spin_unlock(&ino->i_lock);
            BUG_ON(!list_empty(&lo->plh_bulk_recall));
            list_add(&lo->plh_bulk_recall, &recall_list);
        }
    }
    rcu_read_unlock();
    spin_unlock(&clp->cl_lock);

    list_for_each_entry_safe(lo, tmp,
                 &recall_list, plh_bulk_recall) {
        ino = lo->plh_inode;
        spin_lock(&ino->i_lock);
        set_bit(NFS_LAYOUT_BULK_RECALL, &lo->plh_flags);
        if (pnfs_mark_matching_lsegs_invalid(lo, &free_me_list, &range))
            rv = NFS4ERR_DELAY;
        list_del_init(&lo->plh_bulk_recall);
        spin_unlock(&ino->i_lock);
        pnfs_free_lseg_list(&free_me_list);
        pnfs_put_layout_hdr(lo);
        iput(ino);
    }
    return rv;
}

static u32 do_callback_layoutrecall(struct nfs_client *clp,
                    struct cb_layoutrecallargs *args)
{
    u32 res;

    dprintk("%s enter, type=%i\n", __func__, args->cbl_recall_type);
    if (args->cbl_recall_type == RETURN_FILE)
        res = initiate_file_draining(clp, args);
    else
        res = initiate_bulk_draining(clp, args);
    dprintk("%s returning %i\n", __func__, res);
    return res;

}

__be32 nfs4_callback_layoutrecall(struct cb_layoutrecallargs *args,
                  void *dummy, struct cb_process_state *cps)
{
    u32 res;

    dprintk("%s: -->\n", __func__);

    if (cps->clp)
        res = do_callback_layoutrecall(cps->clp, args);
    else
        res = NFS4ERR_OP_NOT_IN_SESSION;

    dprintk("%s: exit with status = %d\n", __func__, res);
    return cpu_to_be32(res);
}

static void pnfs_recall_all_layouts(struct nfs_client *clp)
{
    struct cb_layoutrecallargs args;

    /* Pretend we got a CB_LAYOUTRECALL(ALL) */
    memset(&args, 0, sizeof(args));
    args.cbl_recall_type = RETURN_ALL;
    /* FIXME we ignore errors, what should we do? */
    do_callback_layoutrecall(clp, &args);
}

__be32 nfs4_callback_devicenotify(struct cb_devicenotifyargs *args,
                  void *dummy, struct cb_process_state *cps)
{
    int i;
    __be32 res = 0;
    struct nfs_client *clp = cps->clp;
    struct nfs_server *server = NULL;

    dprintk("%s: -->\n", __func__);

    if (!clp) {
        res = cpu_to_be32(NFS4ERR_OP_NOT_IN_SESSION);
        goto out;
    }

    for (i = 0; i < args->ndevs; i++) {
        struct cb_devicenotifyitem *dev = &args->devs[i];

        if (!server ||
            server->pnfs_curr_ld->id != dev->cbd_layout_type) {
            rcu_read_lock();
            list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
                if (server->pnfs_curr_ld &&
                    server->pnfs_curr_ld->id == dev->cbd_layout_type) {
                    rcu_read_unlock();
                    goto found;
                }
            rcu_read_unlock();
            dprintk("%s: layout type %u not found\n",
                __func__, dev->cbd_layout_type);
            continue;
        }

    found:
        if (dev->cbd_notify_type == NOTIFY_DEVICEID4_CHANGE)
            dprintk("%s: NOTIFY_DEVICEID4_CHANGE not supported, "
                "deleting instead\n", __func__);
        nfs4_delete_deviceid(server->pnfs_curr_ld, clp, &dev->cbd_dev_id);
    }

out:
    kfree(args->devs);
    dprintk("%s: exit with status = %u\n",
        __func__, be32_to_cpu(res));
    return res;
}

/*
 * Validate the sequenceID sent by the server.
 * Return success if the sequenceID is one more than what we last saw on
 * this slot, accounting for wraparound.  Increments the slot's sequence.
 *
 * We don't yet implement a duplicate request cache, instead we set the
 * back channel ca_maxresponsesize_cached to zero. This is OK for now
 * since we only currently implement idempotent callbacks anyway.
 *
 * We have a single slot backchannel at this time, so we don't bother
 * checking the used_slots bit array on the table.  The lower layer guarantees
 * a single outstanding callback request at a time.
 */
static __be32
validate_seqid(struct nfs4_slot_table *tbl, struct cb_sequenceargs * args)
{
    struct nfs4_slot *slot;

    dprintk("%s enter. slotid %d seqid %d\n",
        __func__, args->csa_slotid, args->csa_sequenceid);

    if (args->csa_slotid >= NFS41_BC_MAX_CALLBACKS)
        return htonl(NFS4ERR_BADSLOT);

    slot = tbl->slots + args->csa_slotid;
    dprintk("%s slot table seqid: %d\n", __func__, slot->seq_nr);

    /* Normal */
    if (likely(args->csa_sequenceid == slot->seq_nr + 1)) {
        slot->seq_nr++;
        goto out_ok;
    }

    /* Replay */
    if (args->csa_sequenceid == slot->seq_nr) {
        dprintk("%s seqid %d is a replay\n",
            __func__, args->csa_sequenceid);
        /* Signal process_op to set this error on next op */
        if (args->csa_cachethis == 0)
            return htonl(NFS4ERR_RETRY_UNCACHED_REP);

        /* The ca_maxresponsesize_cached is 0 with no DRC */
        else if (args->csa_cachethis == 1)
            return htonl(NFS4ERR_REP_TOO_BIG_TO_CACHE);
    }

    /* Wraparound */
    if (args->csa_sequenceid == 1 && (slot->seq_nr + 1) == 0) {
        slot->seq_nr = 1;
        goto out_ok;
    }

    /* Misordered request */
    return htonl(NFS4ERR_SEQ_MISORDERED);
out_ok:
    tbl->highest_used_slotid = args->csa_slotid;
    return htonl(NFS4_OK);
}

/*
 * For each referring call triple, check the session's slot table for
 * a match.  If the slot is in use and the sequence numbers match, the
 * client is still waiting for a response to the original request.
 */
static bool referring_call_exists(struct nfs_client *clp,
                  uint32_t nrclists,
                  struct referring_call_list *rclists)
{
    bool status = 0;
    int i, j;
    struct nfs4_session *session;
    struct nfs4_slot_table *tbl;
    struct referring_call_list *rclist;
    struct referring_call *ref;

    /*
     * XXX When client trunking is implemented, this becomes
     * a session lookup from within the loop
     */
    session = clp->cl_session;
    tbl = &session->fc_slot_table;

    for (i = 0; i < nrclists; i++) {
        rclist = &rclists[i];
        if (memcmp(session->sess_id.data,
               rclist->rcl_sessionid.data,
               NFS4_MAX_SESSIONID_LEN) != 0)
            continue;

        for (j = 0; j < rclist->rcl_nrefcalls; j++) {
            ref = &rclist->rcl_refcalls[j];

            dprintk("%s: sessionid %x:%x:%x:%x sequenceid %u "
                "slotid %u\n", __func__,
                ((u32 *)&rclist->rcl_sessionid.data)[0],
                ((u32 *)&rclist->rcl_sessionid.data)[1],
                ((u32 *)&rclist->rcl_sessionid.data)[2],
                ((u32 *)&rclist->rcl_sessionid.data)[3],
                ref->rc_sequenceid, ref->rc_slotid);

            spin_lock(&tbl->slot_tbl_lock);
            status = (test_bit(ref->rc_slotid, tbl->used_slots) &&
                  tbl->slots[ref->rc_slotid].seq_nr ==
                    ref->rc_sequenceid);
            spin_unlock(&tbl->slot_tbl_lock);
            if (status)
                goto out;
        }
    }

out:
    return status;
}

__be32 nfs4_callback_sequence(struct cb_sequenceargs *args,
                  struct cb_sequenceres *res,
                  struct cb_process_state *cps)
{
    struct nfs4_slot_table *tbl;
    struct nfs_client *clp;
    int i;
    __be32 status = htonl(NFS4ERR_BADSESSION);

    clp = nfs4_find_client_sessionid(cps->net, args->csa_addr, &args->csa_sessionid);
    if (clp == NULL)
        goto out;

    tbl = &clp->cl_session->bc_slot_table;

    spin_lock(&tbl->slot_tbl_lock);
    /* state manager is resetting the session */
    if (test_bit(NFS4_SESSION_DRAINING, &clp->cl_session->session_state)) {
        spin_unlock(&tbl->slot_tbl_lock);
        status = htonl(NFS4ERR_DELAY);
        /* Return NFS4ERR_BADSESSION if we're draining the session
         * in order to reset it.
         */
        if (test_bit(NFS4CLNT_SESSION_RESET, &clp->cl_state))
            status = htonl(NFS4ERR_BADSESSION);
        goto out;
    }

    status = validate_seqid(&clp->cl_session->bc_slot_table, args);
    spin_unlock(&tbl->slot_tbl_lock);
    if (status)
        goto out;

    cps->slotid = args->csa_slotid;

    /*
     * Check for pending referring calls.  If a match is found, a
     * related callback was received before the response to the original
     * call.
     */
    if (referring_call_exists(clp, args->csa_nrclists, args->csa_rclists)) {
        status = htonl(NFS4ERR_DELAY);
        goto out;
    }

    memcpy(&res->csr_sessionid, &args->csa_sessionid,
           sizeof(res->csr_sessionid));
    res->csr_sequenceid = args->csa_sequenceid;
    res->csr_slotid = args->csa_slotid;
    res->csr_highestslotid = NFS41_BC_MAX_CALLBACKS - 1;
    res->csr_target_highestslotid = NFS41_BC_MAX_CALLBACKS - 1;

out:
    cps->clp = clp; /* put in nfs4_callback_compound */
    for (i = 0; i < args->csa_nrclists; i++)
        kfree(args->csa_rclists[i].rcl_refcalls);
    kfree(args->csa_rclists);

    if (status == htonl(NFS4ERR_RETRY_UNCACHED_REP)) {
        cps->drc_status = status;
        status = 0;
    } else
        res->csr_status = status;

    dprintk("%s: exit with status = %d res->csr_status %d\n", __func__,
        ntohl(status), ntohl(res->csr_status));
    return status;
}

static bool
validate_bitmap_values(unsigned long mask)
{
    return (mask & ~RCA4_TYPE_MASK_ALL) == 0;
}

__be32 nfs4_callback_recallany(struct cb_recallanyargs *args, void *dummy,
                   struct cb_process_state *cps)
{
    __be32 status;
    fmode_t flags = 0;

    status = cpu_to_be32(NFS4ERR_OP_NOT_IN_SESSION);
    if (!cps->clp) /* set in cb_sequence */
        goto out;

    dprintk_rcu("NFS: RECALL_ANY callback request from %s\n",
        rpc_peeraddr2str(cps->clp->cl_rpcclient, RPC_DISPLAY_ADDR));

    status = cpu_to_be32(NFS4ERR_INVAL);
    if (!validate_bitmap_values(args->craa_type_mask))
        goto out;

    status = cpu_to_be32(NFS4_OK);
    if (test_bit(RCA4_TYPE_MASK_RDATA_DLG, (const unsigned long *)
             &args->craa_type_mask))
        flags = FMODE_READ;
    if (test_bit(RCA4_TYPE_MASK_WDATA_DLG, (const unsigned long *)
             &args->craa_type_mask))
        flags |= FMODE_WRITE;
    if (test_bit(RCA4_TYPE_MASK_FILE_LAYOUT, (const unsigned long *)
             &args->craa_type_mask))
        pnfs_recall_all_layouts(cps->clp);
    if (flags)
        nfs_expire_all_delegation_types(cps->clp, flags);
out:
    dprintk("%s: exit with status = %d\n", __func__, ntohl(status));
    return status;
}

/* Reduce the fore channel's max_slots to the target value */
__be32 nfs4_callback_recallslot(struct cb_recallslotargs *args, void *dummy,
                struct cb_process_state *cps)
{
    struct nfs4_slot_table *fc_tbl;
    __be32 status;

    status = htonl(NFS4ERR_OP_NOT_IN_SESSION);
    if (!cps->clp) /* set in cb_sequence */
        goto out;

    dprintk_rcu("NFS: CB_RECALL_SLOT request from %s target max slots %d\n",
        rpc_peeraddr2str(cps->clp->cl_rpcclient, RPC_DISPLAY_ADDR),
        args->crsa_target_max_slots);

    fc_tbl = &cps->clp->cl_session->fc_slot_table;

    status = htonl(NFS4ERR_BAD_HIGH_SLOT);
    if (args->crsa_target_max_slots > fc_tbl->max_slots ||
        args->crsa_target_max_slots < 1)
        goto out;

    status = htonl(NFS4_OK);
    if (args->crsa_target_max_slots == fc_tbl->max_slots)
        goto out;

    fc_tbl->target_max_slots = args->crsa_target_max_slots;
    nfs41_handle_recall_slot(cps->clp);
out:
    dprintk("%s: exit with status = %d\n", __func__, ntohl(status));
    return status;
}
#endif /* CONFIG_NFS_V4_1 */