/*
 *  fs/nfs/nfs4proc.c
 *
 *  Client-side procedure declarations for NFSv4.
 *
 *  Copyright (c) 2002 The Regents of the University of Michigan.
 *  All rights reserved.
 *
 *  Kendrick Smith <kmsmith@umich.edu>
 *  Andy Adamson   <andros@umich.edu>
 *
 *  Redistribution and use in source and binary forms, with or without
 *  modification, are permitted provided that the following conditions
 *  are met:
 *
 *  1. Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *  2. Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *  3. Neither the name of the University nor the names of its
 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 *  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
 *  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 *  DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 *  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 *  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 *  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
 *  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 *  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 *  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 *  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <linux/mm.h>
#include <linux/delay.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/ratelimit.h>
#include <linux/printk.h>
#include <linux/slab.h>
#include <linux/sunrpc/clnt.h>
#include <linux/nfs.h>
#include <linux/nfs4.h>
#include <linux/nfs_fs.h>
#include <linux/nfs_page.h>
#include <linux/nfs_mount.h>
#include <linux/namei.h>
#include <linux/mount.h>
#include <linux/module.h>
#include <linux/xattr.h>
#include <linux/utsname.h>
#include <linux/freezer.h>
#include <linux/iversion.h>

#include "nfs4_fs.h"
#include "delegation.h"
#include "internal.h"
#include "iostat.h"
#include "callback.h"
#include "pnfs.h"
#include "netns.h"
#include "sysfs.h"
#include "nfs4idmap.h"
#include "nfs4session.h"
#include "fscache.h"
#include "nfs42.h"

#include "nfs4trace.h"

#define NFSDBG_FACILITY         NFSDBG_PROC

#define NFS4_BITMASK_SZ         3

#define NFS4_POLL_RETRY_MIN     (HZ/10)
#define NFS4_POLL_RETRY_MAX     (15*HZ)

/* file attributes which can be mapped to nfs attributes */
#define NFS4_VALID_ATTRS (ATTR_MODE \
        | ATTR_UID \
        | ATTR_GID \
        | ATTR_SIZE \
        | ATTR_ATIME \
        | ATTR_MTIME \
        | ATTR_CTIME \
        | ATTR_ATIME_SET \
        | ATTR_MTIME_SET)

struct nfs4_opendata;
static int _nfs4_recover_proc_open(struct nfs4_opendata *data);
static int nfs4_do_fsinfo(struct nfs_server *, struct nfs_fh *, struct nfs_fsinfo *);
static void nfs_fixup_referral_attributes(struct nfs_fattr *fattr);
static int _nfs4_proc_getattr(struct nfs_server *server, struct nfs_fh *fhandle, struct nfs_fattr *fattr, struct nfs4_label *label, struct inode *inode);
static int nfs4_do_setattr(struct inode *inode, const struct cred *cred,
                            struct nfs_fattr *fattr, struct iattr *sattr,
                            struct nfs_open_context *ctx, struct nfs4_label *ilabel,
                            struct nfs4_label *olabel);
#ifdef CONFIG_NFS_V4_1
static struct rpc_task *_nfs41_proc_sequence(struct nfs_client *clp,
                const struct cred *cred,
                struct nfs4_slot *slot,
                bool is_privileged);
static int nfs41_test_stateid(struct nfs_server *, nfs4_stateid *,
                const struct cred *);
static int nfs41_free_stateid(struct nfs_server *, const nfs4_stateid *,
                const struct cred *, bool);
#endif
static void nfs4_bitmask_set(__u32 bitmask[NFS4_BITMASK_SZ],
                             const __u32 *src, struct inode *inode,
                             struct nfs_server *server,
                             struct nfs4_label *label);

#ifdef CONFIG_NFS_V4_SECURITY_LABEL
static inline struct nfs4_label *
nfs4_label_init_security(struct inode *dir, struct dentry *dentry,
        struct iattr *sattr, struct nfs4_label *label)
{
        int err;

        if (label == NULL)
                return NULL;

        if (nfs_server_capable(dir, NFS_CAP_SECURITY_LABEL) == 0)
                return NULL;

        err = security_dentry_init_security(dentry, sattr->ia_mode,
                                &dentry->d_name, (void **)&label->label, &label->len);
        if (err == 0)
                return label;

        return NULL;
}
static inline void
nfs4_label_release_security(struct nfs4_label *label)
{
        if (label)
                security_release_secctx(label->label, label->len);
}
static inline u32 *nfs4_bitmask(struct nfs_server *server, struct nfs4_label *label)
{
        if (label)
                return server->attr_bitmask;

        return server->attr_bitmask_nl;
}
#else
static inline struct nfs4_label *
nfs4_label_init_security(struct inode *dir, struct dentry *dentry,
        struct iattr *sattr, struct nfs4_label *l)
{ return NULL; }
static inline void
nfs4_label_release_security(struct nfs4_label *label)
{ return; }
static inline u32 *
nfs4_bitmask(struct nfs_server *server, struct nfs4_label *label)
{ return server->attr_bitmask; }
#endif

/* Prevent leaks of NFSv4 errors into userland */
static int nfs4_map_errors(int err)
{
        if (err >= -1000)
                return err;
        switch (err) {
        case -NFS4ERR_RESOURCE:
        case -NFS4ERR_LAYOUTTRYLATER:
        case -NFS4ERR_RECALLCONFLICT:
                return -EREMOTEIO;
        case -NFS4ERR_WRONGSEC:
        case -NFS4ERR_WRONG_CRED:
                return -EPERM;
        case -NFS4ERR_BADOWNER:
        case -NFS4ERR_BADNAME:
                return -EINVAL;
        case -NFS4ERR_SHARE_DENIED:
                return -EACCES;
        case -NFS4ERR_MINOR_VERS_MISMATCH:
                return -EPROTONOSUPPORT;
        case -NFS4ERR_FILE_OPEN:
                return -EBUSY;
        case -NFS4ERR_NOT_SAME:
                return -ENOTSYNC;
        default:
                dprintk("%s could not handle NFSv4 error %d\n",
                                __func__, -err);
                break;
        }
        return -EIO;
}

/*
 * This is our standard bitmap for GETATTR requests.
 */
const u32 nfs4_fattr_bitmap[3] = {
        FATTR4_WORD0_TYPE
        | FATTR4_WORD0_CHANGE
        | FATTR4_WORD0_SIZE
        | FATTR4_WORD0_FSID
        | FATTR4_WORD0_FILEID,
        FATTR4_WORD1_MODE
        | FATTR4_WORD1_NUMLINKS
        | FATTR4_WORD1_OWNER
        | FATTR4_WORD1_OWNER_GROUP
        | FATTR4_WORD1_RAWDEV
        | FATTR4_WORD1_SPACE_USED
        | FATTR4_WORD1_TIME_ACCESS
        | FATTR4_WORD1_TIME_METADATA
        | FATTR4_WORD1_TIME_MODIFY
        | FATTR4_WORD1_MOUNTED_ON_FILEID,
#ifdef CONFIG_NFS_V4_SECURITY_LABEL
        FATTR4_WORD2_SECURITY_LABEL
#endif
};

static const u32 nfs4_pnfs_open_bitmap[3] = {
        FATTR4_WORD0_TYPE
        | FATTR4_WORD0_CHANGE
        | FATTR4_WORD0_SIZE
        | FATTR4_WORD0_FSID
        | FATTR4_WORD0_FILEID,
        FATTR4_WORD1_MODE
        | FATTR4_WORD1_NUMLINKS
        | FATTR4_WORD1_OWNER
        | FATTR4_WORD1_OWNER_GROUP
        | FATTR4_WORD1_RAWDEV
        | FATTR4_WORD1_SPACE_USED
        | FATTR4_WORD1_TIME_ACCESS
        | FATTR4_WORD1_TIME_METADATA
        | FATTR4_WORD1_TIME_MODIFY,
        FATTR4_WORD2_MDSTHRESHOLD
#ifdef CONFIG_NFS_V4_SECURITY_LABEL
        | FATTR4_WORD2_SECURITY_LABEL
#endif
};

static const u32 nfs4_open_noattr_bitmap[3] = {
        FATTR4_WORD0_TYPE
        | FATTR4_WORD0_FILEID,
};

const u32 nfs4_statfs_bitmap[3] = {
        FATTR4_WORD0_FILES_AVAIL
        | FATTR4_WORD0_FILES_FREE
        | FATTR4_WORD0_FILES_TOTAL,
        FATTR4_WORD1_SPACE_AVAIL
        | FATTR4_WORD1_SPACE_FREE
        | FATTR4_WORD1_SPACE_TOTAL
};

const u32 nfs4_pathconf_bitmap[3] = {
        FATTR4_WORD0_MAXLINK
        | FATTR4_WORD0_MAXNAME,
        0
};

const u32 nfs4_fsinfo_bitmap[3] = { FATTR4_WORD0_MAXFILESIZE
                        | FATTR4_WORD0_MAXREAD
                        | FATTR4_WORD0_MAXWRITE
                        | FATTR4_WORD0_LEASE_TIME,
                        FATTR4_WORD1_TIME_DELTA
                        | FATTR4_WORD1_FS_LAYOUT_TYPES,
                        FATTR4_WORD2_LAYOUT_BLKSIZE
                        | FATTR4_WORD2_CLONE_BLKSIZE
                        | FATTR4_WORD2_CHANGE_ATTR_TYPE
                        | FATTR4_WORD2_XATTR_SUPPORT
};

const u32 nfs4_fs_locations_bitmap[3] = {
        FATTR4_WORD0_CHANGE
        | FATTR4_WORD0_SIZE
        | FATTR4_WORD0_FSID
        | FATTR4_WORD0_FILEID
        | FATTR4_WORD0_FS_LOCATIONS,
        FATTR4_WORD1_OWNER
        | FATTR4_WORD1_OWNER_GROUP
        | FATTR4_WORD1_RAWDEV
        | FATTR4_WORD1_SPACE_USED
        | FATTR4_WORD1_TIME_ACCESS
        | FATTR4_WORD1_TIME_METADATA
        | FATTR4_WORD1_TIME_MODIFY
        | FATTR4_WORD1_MOUNTED_ON_FILEID,
};

static void nfs4_bitmap_copy_adjust(__u32 *dst, const __u32 *src,
                                    struct inode *inode, unsigned long flags)
{
        unsigned long cache_validity;

        memcpy(dst, src, NFS4_BITMASK_SZ*sizeof(*dst));
        if (!inode || !nfs4_have_delegation(inode, FMODE_READ))
                return;

        cache_validity = READ_ONCE(NFS_I(inode)->cache_validity) | flags;

        /* Remove the attributes over which we have full control */
        dst[1] &= ~FATTR4_WORD1_RAWDEV;
        if (!(cache_validity & NFS_INO_INVALID_SIZE))
                dst[0] &= ~FATTR4_WORD0_SIZE;

        if (!(cache_validity & NFS_INO_INVALID_CHANGE))
                dst[0] &= ~FATTR4_WORD0_CHANGE;

        if (!(cache_validity & NFS_INO_INVALID_MODE))
                dst[1] &= ~FATTR4_WORD1_MODE;
        if (!(cache_validity & NFS_INO_INVALID_OTHER))
                dst[1] &= ~(FATTR4_WORD1_OWNER | FATTR4_WORD1_OWNER_GROUP);
}

static void nfs4_setup_readdir(u64 cookie, __be32 *verifier, struct dentry *dentry,
                struct nfs4_readdir_arg *readdir)
{
        unsigned int attrs = FATTR4_WORD0_FILEID | FATTR4_WORD0_TYPE;
        __be32 *start, *p;

        if (cookie > 2) {
                readdir->cookie = cookie;
                memcpy(&readdir->verifier, verifier, sizeof(readdir->verifier));
                return;
        }

        readdir->cookie = 0;
        memset(&readdir->verifier, 0, sizeof(readdir->verifier));
        if (cookie == 2)
                return;
        
        /*
         * NFSv4 servers do not return entries for '.' and '..'
         * Therefore, we fake these entries here.  We let '.'
         * have cookie 0 and '..' have cookie 1.  Note that
         * when talking to the server, we always send cookie 0
         * instead of 1 or 2.
         */
        start = p = kmap_atomic(*readdir->pages);
        
        if (cookie == 0) {
                *p++ = xdr_one;                                  /* next */
                *p++ = xdr_zero;                   /* cookie, first word */
                *p++ = xdr_one;                   /* cookie, second word */
                *p++ = xdr_one;                             /* entry len */
                memcpy(p, ".\0\0\0", 4);                        /* entry */
                p++;
                *p++ = xdr_one;                         /* bitmap length */
                *p++ = htonl(attrs);                           /* bitmap */
                *p++ = htonl(12);             /* attribute buffer length */
                *p++ = htonl(NF4DIR);
                p = xdr_encode_hyper(p, NFS_FILEID(d_inode(dentry)));
        }
        
        *p++ = xdr_one;                                  /* next */
        *p++ = xdr_zero;                   /* cookie, first word */
        *p++ = xdr_two;                   /* cookie, second word */
        *p++ = xdr_two;                             /* entry len */
        memcpy(p, "..\0\0", 4);                         /* entry */
        p++;
        *p++ = xdr_one;                         /* bitmap length */
        *p++ = htonl(attrs);                           /* bitmap */
        *p++ = htonl(12);             /* attribute buffer length */
        *p++ = htonl(NF4DIR);
        p = xdr_encode_hyper(p, NFS_FILEID(d_inode(dentry->d_parent)));

        readdir->pgbase = (char *)p - (char *)start;
        readdir->count -= readdir->pgbase;
        kunmap_atomic(start);
}

static void nfs4_test_and_free_stateid(struct nfs_server *server,
                nfs4_stateid *stateid,
                const struct cred *cred)
{
        const struct nfs4_minor_version_ops *ops = server->nfs_client->cl_mvops;

        ops->test_and_free_expired(server, stateid, cred);
}

static void __nfs4_free_revoked_stateid(struct nfs_server *server,
                nfs4_stateid *stateid,
                const struct cred *cred)
{
        stateid->type = NFS4_REVOKED_STATEID_TYPE;
        nfs4_test_and_free_stateid(server, stateid, cred);
}

static void nfs4_free_revoked_stateid(struct nfs_server *server,
                const nfs4_stateid *stateid,
                const struct cred *cred)
{
        nfs4_stateid tmp;

        nfs4_stateid_copy(&tmp, stateid);
        __nfs4_free_revoked_stateid(server, &tmp, cred);
}

static long nfs4_update_delay(long *timeout)
{
        long ret;
        if (!timeout)
                return NFS4_POLL_RETRY_MAX;
        if (*timeout <= 0)
                *timeout = NFS4_POLL_RETRY_MIN;
        if (*timeout > NFS4_POLL_RETRY_MAX)
                *timeout = NFS4_POLL_RETRY_MAX;
        ret = *timeout;
        *timeout <<= 1;
        return ret;
}

static int nfs4_delay_killable(long *timeout)
{
        might_sleep();

        freezable_schedule_timeout_killable_unsafe(
                nfs4_update_delay(timeout));
        if (!__fatal_signal_pending(current))
                return 0;
        return -EINTR;
}

static int nfs4_delay_interruptible(long *timeout)
{
        might_sleep();

        freezable_schedule_timeout_interruptible_unsafe(nfs4_update_delay(timeout));
        if (!signal_pending(current))
                return 0;
        return __fatal_signal_pending(current) ? -EINTR :-ERESTARTSYS;
}

static int nfs4_delay(long *timeout, bool interruptible)
{
        if (interruptible)
                return nfs4_delay_interruptible(timeout);
        return nfs4_delay_killable(timeout);
}

static const nfs4_stateid *
nfs4_recoverable_stateid(const nfs4_stateid *stateid)
{
        if (!stateid)
                return NULL;
        switch (stateid->type) {
        case NFS4_OPEN_STATEID_TYPE:
        case NFS4_LOCK_STATEID_TYPE:
        case NFS4_DELEGATION_STATEID_TYPE:
                return stateid;
        default:
                break;
        }
        return NULL;
}

/* This is the error handling routine for processes that are allowed
 * to sleep.
 */
static int nfs4_do_handle_exception(struct nfs_server *server,
                int errorcode, struct nfs4_exception *exception)
{
        struct nfs_client *clp = server->nfs_client;
        struct nfs4_state *state = exception->state;
        const nfs4_stateid *stateid;
        struct inode *inode = exception->inode;
        int ret = errorcode;

        exception->delay = 0;
        exception->recovering = 0;
        exception->retry = 0;

        stateid = nfs4_recoverable_stateid(exception->stateid);
        if (stateid == NULL && state != NULL)
                stateid = nfs4_recoverable_stateid(&state->stateid);

        switch(errorcode) {
                case 0:
                        return 0;
                case -NFS4ERR_BADHANDLE:
                case -ESTALE:
                        if (inode != NULL && S_ISREG(inode->i_mode))
                                pnfs_destroy_layout(NFS_I(inode));
                        break;
                case -NFS4ERR_DELEG_REVOKED:
                case -NFS4ERR_ADMIN_REVOKED:
                case -NFS4ERR_EXPIRED:
                case -NFS4ERR_BAD_STATEID:
                case -NFS4ERR_PARTNER_NO_AUTH:
                        if (inode != NULL && stateid != NULL) {
                                nfs_inode_find_state_and_recover(inode,
                                                stateid);
                                goto wait_on_recovery;
                        }
                        fallthrough;
                case -NFS4ERR_OPENMODE:
                        if (inode) {
                                int err;

                                err = nfs_async_inode_return_delegation(inode,
                                                stateid);
                                if (err == 0)
                                        goto wait_on_recovery;
                                if (stateid != NULL && stateid->type == NFS4_DELEGATION_STATEID_TYPE) {
                                        exception->retry = 1;
                                        break;
                                }
                        }
                        if (state == NULL)
                                break;
                        ret = nfs4_schedule_stateid_recovery(server, state);
                        if (ret < 0)
                                break;
                        goto wait_on_recovery;
                case -NFS4ERR_STALE_STATEID:
                case -NFS4ERR_STALE_CLIENTID:
                        nfs4_schedule_lease_recovery(clp);
                        goto wait_on_recovery;
                case -NFS4ERR_MOVED:
                        ret = nfs4_schedule_migration_recovery(server);
                        if (ret < 0)
                                break;
                        goto wait_on_recovery;
                case -NFS4ERR_LEASE_MOVED:
                        nfs4_schedule_lease_moved_recovery(clp);
                        goto wait_on_recovery;
#if defined(CONFIG_NFS_V4_1)
                case -NFS4ERR_BADSESSION:
                case -NFS4ERR_BADSLOT:
                case -NFS4ERR_BAD_HIGH_SLOT:
                case -NFS4ERR_CONN_NOT_BOUND_TO_SESSION:
                case -NFS4ERR_DEADSESSION:
                case -NFS4ERR_SEQ_FALSE_RETRY:
                case -NFS4ERR_SEQ_MISORDERED:
                        /* Handled in nfs41_sequence_process() */
                        goto wait_on_recovery;
#endif /* defined(CONFIG_NFS_V4_1) */
                case -NFS4ERR_FILE_OPEN:
                        if (exception->timeout > HZ) {
                                /* We have retried a decent amount, time to
                                 * fail
                                 */
                                ret = -EBUSY;
                                break;
                        }
                        fallthrough;
                case -NFS4ERR_DELAY:
                        nfs_inc_server_stats(server, NFSIOS_DELAY);
                        fallthrough;
                case -NFS4ERR_GRACE:
                case -NFS4ERR_LAYOUTTRYLATER:
                case -NFS4ERR_RECALLCONFLICT:
                        exception->delay = 1;
                        return 0;

                case -NFS4ERR_RETRY_UNCACHED_REP:
                case -NFS4ERR_OLD_STATEID:
                        exception->retry = 1;
                        break;
                case -NFS4ERR_BADOWNER:
                        /* The following works around a Linux server bug! */
                case -NFS4ERR_BADNAME:
                        if (server->caps & NFS_CAP_UIDGID_NOMAP) {
                                server->caps &= ~NFS_CAP_UIDGID_NOMAP;
                                exception->retry = 1;
                                printk(KERN_WARNING "NFS: v4 server %s "
                                                "does not accept raw "
                                                "uid/gids. "
                                                "Reenabling the idmapper.\n",
                                                server->nfs_client->cl_hostname);
                        }
        }
        /* We failed to handle the error */
        return nfs4_map_errors(ret);
wait_on_recovery:
        exception->recovering = 1;
        return 0;
}

/* This is the error handling routine for processes that are allowed
 * to sleep.
 */
int nfs4_handle_exception(struct nfs_server *server, int errorcode, struct nfs4_exception *exception)
{
        struct nfs_client *clp = server->nfs_client;
        int ret;

        ret = nfs4_do_handle_exception(server, errorcode, exception);
        if (exception->delay) {
                ret = nfs4_delay(&exception->timeout,
                                exception->interruptible);
                goto out_retry;
        }
        if (exception->recovering) {
                if (exception->task_is_privileged)
                        return -EDEADLOCK;
                ret = nfs4_wait_clnt_recover(clp);
                if (test_bit(NFS_MIG_FAILED, &server->mig_status))
                        return -EIO;
                goto out_retry;
        }
        return ret;
out_retry:
        if (ret == 0)
                exception->retry = 1;
        return ret;
}

static int
nfs4_async_handle_exception(struct rpc_task *task, struct nfs_server *server,
                int errorcode, struct nfs4_exception *exception)
{
        struct nfs_client *clp = server->nfs_client;
        int ret;

        ret = nfs4_do_handle_exception(server, errorcode, exception);
        if (exception->delay) {
                rpc_delay(task, nfs4_update_delay(&exception->timeout));
                goto out_retry;
        }
        if (exception->recovering) {
                if (exception->task_is_privileged)
                        return -EDEADLOCK;
                rpc_sleep_on(&clp->cl_rpcwaitq, task, NULL);
                if (test_bit(NFS4CLNT_MANAGER_RUNNING, &clp->cl_state) == 0)
                        rpc_wake_up_queued_task(&clp->cl_rpcwaitq, task);
                goto out_retry;
        }
        if (test_bit(NFS_MIG_FAILED, &server->mig_status))
                ret = -EIO;
        return ret;
out_retry:
        if (ret == 0) {
                exception->retry = 1;
                /*
                 * For NFS4ERR_MOVED, the client transport will need to
                 * be recomputed after migration recovery has completed.
                 */
                if (errorcode == -NFS4ERR_MOVED)
                        rpc_task_release_transport(task);
        }
        return ret;
}

int
nfs4_async_handle_error(struct rpc_task *task, struct nfs_server *server,
                        struct nfs4_state *state, long *timeout)
{
        struct nfs4_exception exception = {
                .state = state,
        };

        if (task->tk_status >= 0)
                return 0;
        if (timeout)
                exception.timeout = *timeout;
        task->tk_status = nfs4_async_handle_exception(task, server,
                        task->tk_status,
                        &exception);
        if (exception.delay && timeout)
                *timeout = exception.timeout;
        if (exception.retry)
                return -EAGAIN;
        return 0;
}

/*
 * Return 'true' if 'clp' is using an rpc_client that is integrity protected
 * or 'false' otherwise.
 */
static bool _nfs4_is_integrity_protected(struct nfs_client *clp)
{
        rpc_authflavor_t flavor = clp->cl_rpcclient->cl_auth->au_flavor;
        return (flavor == RPC_AUTH_GSS_KRB5I) || (flavor == RPC_AUTH_GSS_KRB5P);
}

static void do_renew_lease(struct nfs_client *clp, unsigned long timestamp)
{
        spin_lock(&clp->cl_lock);
        if (time_before(clp->cl_last_renewal,timestamp))
                clp->cl_last_renewal = timestamp;
        spin_unlock(&clp->cl_lock);
}

static void renew_lease(const struct nfs_server *server, unsigned long timestamp)
{
        struct nfs_client *clp = server->nfs_client;

        if (!nfs4_has_session(clp))
                do_renew_lease(clp, timestamp);
}

struct nfs4_call_sync_data {
        const struct nfs_server *seq_server;
        struct nfs4_sequence_args *seq_args;
        struct nfs4_sequence_res *seq_res;
};

void nfs4_init_sequence(struct nfs4_sequence_args *args,
                        struct nfs4_sequence_res *res, int cache_reply,
                        int privileged)
{
        args->sa_slot = NULL;
        args->sa_cache_this = cache_reply;
        args->sa_privileged = privileged;

        res->sr_slot = NULL;
}

static void nfs40_sequence_free_slot(struct nfs4_sequence_res *res)
{
        struct nfs4_slot *slot = res->sr_slot;
        struct nfs4_slot_table *tbl;

        tbl = slot->table;
        spin_lock(&tbl->slot_tbl_lock);
        if (!nfs41_wake_and_assign_slot(tbl, slot))
                nfs4_free_slot(tbl, slot);
        spin_unlock(&tbl->slot_tbl_lock);

        res->sr_slot = NULL;
}

static int nfs40_sequence_done(struct rpc_task *task,
                               struct nfs4_sequence_res *res)
{
        if (res->sr_slot != NULL)
                nfs40_sequence_free_slot(res);
        return 1;
}

#if defined(CONFIG_NFS_V4_1)

static void nfs41_release_slot(struct nfs4_slot *slot)
{
        struct nfs4_session *session;
        struct nfs4_slot_table *tbl;
        bool send_new_highest_used_slotid = false;

        if (!slot)
                return;
        tbl = slot->table;
        session = tbl->session;

        /* Bump the slot sequence number */
        if (slot->seq_done)
                slot->seq_nr++;
        slot->seq_done = 0;

        spin_lock(&tbl->slot_tbl_lock);
        /* Be nice to the server: try to ensure that the last transmitted
         * value for highest_user_slotid <= target_highest_slotid
         */
        if (tbl->highest_used_slotid > tbl->target_highest_slotid)
                send_new_highest_used_slotid = true;

        if (nfs41_wake_and_assign_slot(tbl, slot)) {
                send_new_highest_used_slotid = false;
                goto out_unlock;
        }
        nfs4_free_slot(tbl, slot);

        if (tbl->highest_used_slotid != NFS4_NO_SLOT)
                send_new_highest_used_slotid = false;
out_unlock:
        spin_unlock(&tbl->slot_tbl_lock);
        if (send_new_highest_used_slotid)
                nfs41_notify_server(session->clp);
        if (waitqueue_active(&tbl->slot_waitq))
                wake_up_all(&tbl->slot_waitq);
}

static void nfs41_sequence_free_slot(struct nfs4_sequence_res *res)
{
        nfs41_release_slot(res->sr_slot);
        res->sr_slot = NULL;
}

static void nfs4_slot_sequence_record_sent(struct nfs4_slot *slot,
                u32 seqnr)
{
        if ((s32)(seqnr - slot->seq_nr_highest_sent) > 0)
                slot->seq_nr_highest_sent = seqnr;
}
static void nfs4_slot_sequence_acked(struct nfs4_slot *slot,
                u32 seqnr)
{
        slot->seq_nr_highest_sent = seqnr;
        slot->seq_nr_last_acked = seqnr;
}

static void nfs4_probe_sequence(struct nfs_client *client, const struct cred *cred,
                                struct nfs4_slot *slot)
{
        struct rpc_task *task = _nfs41_proc_sequence(client, cred, slot, true);
        if (!IS_ERR(task))
                rpc_put_task_async(task);
}

static int nfs41_sequence_process(struct rpc_task *task,
                struct nfs4_sequence_res *res)
{
        struct nfs4_session *session;
        struct nfs4_slot *slot = res->sr_slot;
        struct nfs_client *clp;
        int status;
        int ret = 1;

        if (slot == NULL)
                goto out_noaction;
        /* don't increment the sequence number if the task wasn't sent */
        if (!RPC_WAS_SENT(task) || slot->seq_done)
                goto out;

        session = slot->table->session;
        clp = session->clp;

        trace_nfs4_sequence_done(session, res);

        status = res->sr_status;
        if (task->tk_status == -NFS4ERR_DEADSESSION)
                status = -NFS4ERR_DEADSESSION;

        /* Check the SEQUENCE operation status */
        switch (status) {
        case 0:
                /* Mark this sequence number as having been acked */
                nfs4_slot_sequence_acked(slot, slot->seq_nr);
                /* Update the slot's sequence and clientid lease timer */
                slot->seq_done = 1;
                do_renew_lease(clp, res->sr_timestamp);
                /* Check sequence flags */
                nfs41_handle_sequence_flag_errors(clp, res->sr_status_flags,
                                !!slot->privileged);
                nfs41_update_target_slotid(slot->table, slot, res);
                break;
        case 1:
                /*
                 * sr_status remains 1 if an RPC level error occurred.
                 * The server may or may not have processed the sequence
                 * operation..
                 */
                nfs4_slot_sequence_record_sent(slot, slot->seq_nr);
                slot->seq_done = 1;
                goto out;
        case -NFS4ERR_DELAY:
                /* The server detected a resend of the RPC call and
                 * returned NFS4ERR_DELAY as per Section 2.10.6.2
                 * of RFC5661.
                 */
                dprintk("%s: slot=%u seq=%u: Operation in progress\n",
                        __func__,
                        slot->slot_nr,
                        slot->seq_nr);
                nfs4_slot_sequence_acked(slot, slot->seq_nr);
                goto out_retry;
        case -NFS4ERR_RETRY_UNCACHED_REP:
        case -NFS4ERR_SEQ_FALSE_RETRY:
                /*
                 * The server thinks we tried to replay a request.
                 * Retry the call after bumping the sequence ID.
                 */
                nfs4_slot_sequence_acked(slot, slot->seq_nr);
                goto retry_new_seq;
        case -NFS4ERR_BADSLOT:
                /*
                 * The slot id we used was probably retired. Try again
                 * using a different slot id.
                 */
                if (slot->slot_nr < slot->table->target_highest_slotid)
                        goto session_recover;
                goto retry_nowait;
        case -NFS4ERR_SEQ_MISORDERED:
                nfs4_slot_sequence_record_sent(slot, slot->seq_nr);
                /*
                 * Were one or more calls using this slot interrupted?
                 * If the server never received the request, then our
                 * transmitted slot sequence number may be too high. However,
                 * if the server did receive the request then it might
                 * accidentally give us a reply with a mismatched operation.
                 * We can sort this out by sending a lone sequence operation
                 * to the server on the same slot.
                 */
                if ((s32)(slot->seq_nr - slot->seq_nr_last_acked) > 1) {
                        slot->seq_nr--;
                        if (task->tk_msg.rpc_proc != &nfs4_procedures[NFSPROC4_CLNT_SEQUENCE]) {
                                nfs4_probe_sequence(clp, task->tk_msg.rpc_cred, slot);
                                res->sr_slot = NULL;
                        }
                        goto retry_nowait;
                }
                /*
                 * RFC5661:
                 * A retry might be sent while the original request is
                 * still in progress on the replier. The replier SHOULD
                 * deal with the issue by returning NFS4ERR_DELAY as the
                 * reply to SEQUENCE or CB_SEQUENCE operation, but
                 * implementations MAY return NFS4ERR_SEQ_MISORDERED.
                 *
                 * Restart the search after a delay.
                 */
                slot->seq_nr = slot->seq_nr_highest_sent;
                goto out_retry;
        case -NFS4ERR_BADSESSION:
        case -NFS4ERR_DEADSESSION:
        case -NFS4ERR_CONN_NOT_BOUND_TO_SESSION:
                goto session_recover;
        default:
                /* Just update the slot sequence no. */
                slot->seq_done = 1;
        }
out:
        /* The session may be reset by one of the error handlers. */
        dprintk("%s: Error %d free the slot \n", __func__, res->sr_status);
out_noaction:
        return ret;
session_recover:
        nfs4_schedule_session_recovery(session, status);
        dprintk("%s ERROR: %d Reset session\n", __func__, status);
        nfs41_sequence_free_slot(res);
        goto out;
retry_new_seq:
        ++slot->seq_nr;
retry_nowait:
        if (rpc_restart_call_prepare(task)) {
                nfs41_sequence_free_slot(res);
                task->tk_status = 0;
                ret = 0;
        }
        goto out;
out_retry:
        if (!rpc_restart_call(task))
                goto out;
        rpc_delay(task, NFS4_POLL_RETRY_MAX);
        return 0;
}

int nfs41_sequence_done(struct rpc_task *task, struct nfs4_sequence_res *res)
{
        if (!nfs41_sequence_process(task, res))
                return 0;
        if (res->sr_slot != NULL)
                nfs41_sequence_free_slot(res);
        return 1;

}
EXPORT_SYMBOL_GPL(nfs41_sequence_done);

static int nfs4_sequence_process(struct rpc_task *task, struct nfs4_sequence_res *res)
{
        if (res->sr_slot == NULL)
                return 1;
        if (res->sr_slot->table->session != NULL)
                return nfs41_sequence_process(task, res);
        return nfs40_sequence_done(task, res);
}

static void nfs4_sequence_free_slot(struct nfs4_sequence_res *res)
{
        if (res->sr_slot != NULL) {
                if (res->sr_slot->table->session != NULL)
                        nfs41_sequence_free_slot(res);
                else
                        nfs40_sequence_free_slot(res);
        }
}

int nfs4_sequence_done(struct rpc_task *task, struct nfs4_sequence_res *res)
{
        if (res->sr_slot == NULL)
                return 1;
        if (!res->sr_slot->table->session)
                return nfs40_sequence_done(task, res);
        return nfs41_sequence_done(task, res);
}
EXPORT_SYMBOL_GPL(nfs4_sequence_done);

static void nfs41_call_sync_prepare(struct rpc_task *task, void *calldata)
{
        struct nfs4_call_sync_data *data = calldata;

        dprintk("--> %s data->seq_server %p\n", __func__, data->seq_server);

        nfs4_setup_sequence(data->seq_server->nfs_client,
                            data->seq_args, data->seq_res, task);
}

static void nfs41_call_sync_done(struct rpc_task *task, void *calldata)
{
        struct nfs4_call_sync_data *data = calldata;

        nfs41_sequence_done(task, data->seq_res);
}

static const struct rpc_call_ops nfs41_call_sync_ops = {
        .rpc_call_prepare = nfs41_call_sync_prepare,
        .rpc_call_done = nfs41_call_sync_done,
};

#else   /* !CONFIG_NFS_V4_1 */

static int nfs4_sequence_process(struct rpc_task *task, struct nfs4_sequence_res *res)
{

        return nfs40_sequence_done(task, res);
}

static void nfs4_sequence_free_slot(struct nfs4_sequence_res *res)
{
        if (res->sr_slot != NULL)
                nfs40_sequence_free_slot(res);
}

int nfs4_sequence_done(struct rpc_task *task,
                       struct nfs4_sequence_res *res)
{
        return nfs40_sequence_done(task, res);
}
EXPORT_SYMBOL_GPL(nfs4_sequence_done);

#endif  /* !CONFIG_NFS_V4_1 */

static void nfs41_sequence_res_init(struct nfs4_sequence_res *res)
{
        res->sr_timestamp = jiffies;
        res->sr_status_flags = 0;
        res->sr_status = 1;
}

static
void nfs4_sequence_attach_slot(struct nfs4_sequence_args *args,
                struct nfs4_sequence_res *res,
                struct nfs4_slot *slot)
{
        if (!slot)
                return;
        slot->privileged = args->sa_privileged ? 1 : 0;
        args->sa_slot = slot;

        res->sr_slot = slot;
}

int nfs4_setup_sequence(struct nfs_client *client,
                        struct nfs4_sequence_args *args,
                        struct nfs4_sequence_res *res,
                        struct rpc_task *task)
{
        struct nfs4_session *session = nfs4_get_session(client);
        struct nfs4_slot_table *tbl  = client->cl_slot_tbl;
        struct nfs4_slot *slot;

        /* slot already allocated? */
        if (res->sr_slot != NULL)
                goto out_start;

        if (session)
                tbl = &session->fc_slot_table;

        spin_lock(&tbl->slot_tbl_lock);
        /* The state manager will wait until the slot table is empty */
        if (nfs4_slot_tbl_draining(tbl) && !args->sa_privileged)
                goto out_sleep;

        slot = nfs4_alloc_slot(tbl);
        if (IS_ERR(slot)) {
                if (slot == ERR_PTR(-ENOMEM))
                        goto out_sleep_timeout;
                goto out_sleep;
        }
        spin_unlock(&tbl->slot_tbl_lock);

        nfs4_sequence_attach_slot(args, res, slot);

        trace_nfs4_setup_sequence(session, args);
out_start:
        nfs41_sequence_res_init(res);
        rpc_call_start(task);
        return 0;
out_sleep_timeout:
        /* Try again in 1/4 second */
        if (args->sa_privileged)
                rpc_sleep_on_priority_timeout(&tbl->slot_tbl_waitq, task,
                                jiffies + (HZ >> 2), RPC_PRIORITY_PRIVILEGED);
        else
                rpc_sleep_on_timeout(&tbl->slot_tbl_waitq, task,
                                NULL, jiffies + (HZ >> 2));
        spin_unlock(&tbl->slot_tbl_lock);
        return -EAGAIN;
out_sleep:
        if (args->sa_privileged)
                rpc_sleep_on_priority(&tbl->slot_tbl_waitq, task,
                                RPC_PRIORITY_PRIVILEGED);
        else
                rpc_sleep_on(&tbl->slot_tbl_waitq, task, NULL);
        spin_unlock(&tbl->slot_tbl_lock);
        return -EAGAIN;
}
EXPORT_SYMBOL_GPL(nfs4_setup_sequence);

static void nfs40_call_sync_prepare(struct rpc_task *task, void *calldata)
{
        struct nfs4_call_sync_data *data = calldata;
        nfs4_setup_sequence(data->seq_server->nfs_client,
                                data->seq_args, data->seq_res, task);
}

static void nfs40_call_sync_done(struct rpc_task *task, void *calldata)
{
        struct nfs4_call_sync_data *data = calldata;
        nfs4_sequence_done(task, data->seq_res);
}

static const struct rpc_call_ops nfs40_call_sync_ops = {
        .rpc_call_prepare = nfs40_call_sync_prepare,
        .rpc_call_done = nfs40_call_sync_done,
};

static int nfs4_call_sync_custom(struct rpc_task_setup *task_setup)
{
        int ret;
        struct rpc_task *task;

        task = rpc_run_task(task_setup);
        if (IS_ERR(task))
                return PTR_ERR(task);

        ret = task->tk_status;
        rpc_put_task(task);
        return ret;
}

static int nfs4_do_call_sync(struct rpc_clnt *clnt,
                             struct nfs_server *server,
                             struct rpc_message *msg,
                             struct nfs4_sequence_args *args,
                             struct nfs4_sequence_res *res,
                             unsigned short task_flags)
{
        struct nfs_client *clp = server->nfs_client;
        struct nfs4_call_sync_data data = {
                .seq_server = server,
                .seq_args = args,
                .seq_res = res,
        };
        struct rpc_task_setup task_setup = {
                .rpc_client = clnt,
                .rpc_message = msg,
                .callback_ops = clp->cl_mvops->call_sync_ops,
                .callback_data = &data,
                .flags = task_flags,
        };

        return nfs4_call_sync_custom(&task_setup);
}

static int nfs4_call_sync_sequence(struct rpc_clnt *clnt,
                                   struct nfs_server *server,
                                   struct rpc_message *msg,
                                   struct nfs4_sequence_args *args,
                                   struct nfs4_sequence_res *res)
{
        unsigned short task_flags = 0;

        if (server->nfs_client->cl_minorversion)
                task_flags = RPC_TASK_MOVEABLE;
        return nfs4_do_call_sync(clnt, server, msg, args, res, task_flags);
}


int nfs4_call_sync(struct rpc_clnt *clnt,
                   struct nfs_server *server,
                   struct rpc_message *msg,
                   struct nfs4_sequence_args *args,
                   struct nfs4_sequence_res *res,
                   int cache_reply)
{
        nfs4_init_sequence(args, res, cache_reply, 0);
        return nfs4_call_sync_sequence(clnt, server, msg, args, res);
}

static void
nfs4_inc_nlink_locked(struct inode *inode)
{
        nfs_set_cache_invalid(inode, NFS_INO_INVALID_CHANGE |
                                             NFS_INO_INVALID_CTIME |
                                             NFS_INO_INVALID_NLINK);
        inc_nlink(inode);
}

static void
nfs4_inc_nlink(struct inode *inode)
{
        spin_lock(&inode->i_lock);
        nfs4_inc_nlink_locked(inode);
        spin_unlock(&inode->i_lock);
}

static void
nfs4_dec_nlink_locked(struct inode *inode)
{
        nfs_set_cache_invalid(inode, NFS_INO_INVALID_CHANGE |
                                             NFS_INO_INVALID_CTIME |
                                             NFS_INO_INVALID_NLINK);
        drop_nlink(inode);
}

static void
nfs4_update_changeattr_locked(struct inode *inode,
                struct nfs4_change_info *cinfo,
                unsigned long timestamp, unsigned long cache_validity)
{
        struct nfs_inode *nfsi = NFS_I(inode);
        u64 change_attr = inode_peek_iversion_raw(inode);

        cache_validity |= NFS_INO_INVALID_CTIME | NFS_INO_INVALID_MTIME;
        if (S_ISDIR(inode->i_mode))
                cache_validity |= NFS_INO_INVALID_DATA;

        switch (NFS_SERVER(inode)->change_attr_type) {
        case NFS4_CHANGE_TYPE_IS_UNDEFINED:
                if (cinfo->after == change_attr)
                        goto out;
                break;
        default:
                if ((s64)(change_attr - cinfo->after) >= 0)
                        goto out;
        }

        inode_set_iversion_raw(inode, cinfo->after);
        if (!cinfo->atomic || cinfo->before != change_attr) {
                if (S_ISDIR(inode->i_mode))
                        nfs_force_lookup_revalidate(inode);

                if (!NFS_PROTO(inode)->have_delegation(inode, FMODE_READ))
                        cache_validity |=
                                NFS_INO_INVALID_ACCESS | NFS_INO_INVALID_ACL |
                                NFS_INO_INVALID_SIZE | NFS_INO_INVALID_OTHER |
                                NFS_INO_INVALID_BLOCKS | NFS_INO_INVALID_NLINK |
                                NFS_INO_INVALID_MODE | NFS_INO_INVALID_XATTR |
                                NFS_INO_REVAL_PAGECACHE;
                nfsi->attrtimeo = NFS_MINATTRTIMEO(inode);
        }
        nfsi->attrtimeo_timestamp = jiffies;
        nfsi->read_cache_jiffies = timestamp;
        nfsi->attr_gencount = nfs_inc_attr_generation_counter();
        nfsi->cache_validity &= ~NFS_INO_INVALID_CHANGE;
out:
        nfs_set_cache_invalid(inode, cache_validity);
}

void
nfs4_update_changeattr(struct inode *dir, struct nfs4_change_info *cinfo,
                unsigned long timestamp, unsigned long cache_validity)
{
        spin_lock(&dir->i_lock);
        nfs4_update_changeattr_locked(dir, cinfo, timestamp, cache_validity);
        spin_unlock(&dir->i_lock);
}

struct nfs4_open_createattrs {
        struct nfs4_label *label;
        struct iattr *sattr;
        const __u32 verf[2];
};

static bool nfs4_clear_cap_atomic_open_v1(struct nfs_server *server,
                int err, struct nfs4_exception *exception)
{
        if (err != -EINVAL)
                return false;
        if (!(server->caps & NFS_CAP_ATOMIC_OPEN_V1))
                return false;
        server->caps &= ~NFS_CAP_ATOMIC_OPEN_V1;
        exception->retry = 1;
        return true;
}

static fmode_t _nfs4_ctx_to_accessmode(const struct nfs_open_context *ctx)
{
         return ctx->mode & (FMODE_READ|FMODE_WRITE|FMODE_EXEC);
}

static fmode_t _nfs4_ctx_to_openmode(const struct nfs_open_context *ctx)
{
        fmode_t ret = ctx->mode & (FMODE_READ|FMODE_WRITE);

        return (ctx->mode & FMODE_EXEC) ? FMODE_READ | ret : ret;
}

static u32
nfs4_map_atomic_open_share(struct nfs_server *server,
                fmode_t fmode, int openflags)
{
        u32 res = 0;

        switch (fmode & (FMODE_READ | FMODE_WRITE)) {
        case FMODE_READ:
                res = NFS4_SHARE_ACCESS_READ;
                break;
        case FMODE_WRITE:
                res = NFS4_SHARE_ACCESS_WRITE;
                break;
        case FMODE_READ|FMODE_WRITE:
                res = NFS4_SHARE_ACCESS_BOTH;
        }
        if (!(server->caps & NFS_CAP_ATOMIC_OPEN_V1))
                goto out;
        /* Want no delegation if we're using O_DIRECT */
        if (openflags & O_DIRECT)
                res |= NFS4_SHARE_WANT_NO_DELEG;
out:
        return res;
}

static enum open_claim_type4
nfs4_map_atomic_open_claim(struct nfs_server *server,
                enum open_claim_type4 claim)
{
        if (server->caps & NFS_CAP_ATOMIC_OPEN_V1)
                return claim;
        switch (claim) {
        default:
                return claim;
        case NFS4_OPEN_CLAIM_FH:
                return NFS4_OPEN_CLAIM_NULL;
        case NFS4_OPEN_CLAIM_DELEG_CUR_FH:
                return NFS4_OPEN_CLAIM_DELEGATE_CUR;
        case NFS4_OPEN_CLAIM_DELEG_PREV_FH:
                return NFS4_OPEN_CLAIM_DELEGATE_PREV;
        }
}

static void nfs4_init_opendata_res(struct nfs4_opendata *p)
{
        p->o_res.f_attr = &p->f_attr;
        p->o_res.f_label = p->f_label;
        p->o_res.seqid = p->o_arg.seqid;
        p->c_res.seqid = p->c_arg.seqid;
        p->o_res.server = p->o_arg.server;
        p->o_res.access_request = p->o_arg.access;
        nfs_fattr_init(&p->f_attr);
        nfs_fattr_init_names(&p->f_attr, &p->owner_name, &p->group_name);
}

static struct nfs4_opendata *nfs4_opendata_alloc(struct dentry *dentry,
                struct nfs4_state_owner *sp, fmode_t fmode, int flags,
                const struct nfs4_open_createattrs *c,
                enum open_claim_type4 claim,
                gfp_t gfp_mask)
{
        struct dentry *parent = dget_parent(dentry);
        struct inode *dir = d_inode(parent);
        struct nfs_server *server = NFS_SERVER(dir);
        struct nfs_seqid *(*alloc_seqid)(struct nfs_seqid_counter *, gfp_t);
        struct nfs4_label *label = (c != NULL) ? c->label : NULL;
        struct nfs4_opendata *p;

        p = kzalloc(sizeof(*p), gfp_mask);
        if (p == NULL)
                goto err;

        p->f_label = nfs4_label_alloc(server, gfp_mask);
        if (IS_ERR(p->f_label))
                goto err_free_p;

        p->a_label = nfs4_label_alloc(server, gfp_mask);
        if (IS_ERR(p->a_label))
                goto err_free_f;

        alloc_seqid = server->nfs_client->cl_mvops->alloc_seqid;
        p->o_arg.seqid = alloc_seqid(&sp->so_seqid, gfp_mask);
        if (IS_ERR(p->o_arg.seqid))
                goto err_free_label;
        nfs_sb_active(dentry->d_sb);
        p->dentry = dget(dentry);
        p->dir = parent;
        p->owner = sp;
        atomic_inc(&sp->so_count);
        p->o_arg.open_flags = flags;
        p->o_arg.fmode = fmode & (FMODE_READ|FMODE_WRITE);
        p->o_arg.claim = nfs4_map_atomic_open_claim(server, claim);
        p->o_arg.share_access = nfs4_map_atomic_open_share(server,
                        fmode, flags);
        if (flags & O_CREAT) {
                p->o_arg.umask = current_umask();
                p->o_arg.label = nfs4_label_copy(p->a_label, label);
                if (c->sattr != NULL && c->sattr->ia_valid != 0) {
                        p->o_arg.u.attrs = &p->attrs;
                        memcpy(&p->attrs, c->sattr, sizeof(p->attrs));

                        memcpy(p->o_arg.u.verifier.data, c->verf,
                                        sizeof(p->o_arg.u.verifier.data));
                }
        }
        /* don't put an ACCESS op in OPEN compound if O_EXCL, because ACCESS
         * will return permission denied for all bits until close */
        if (!(flags & O_EXCL)) {
                /* ask server to check for all possible rights as results
                 * are cached */
                switch (p->o_arg.claim) {
                default:
                        break;
                case NFS4_OPEN_CLAIM_NULL:
                case NFS4_OPEN_CLAIM_FH:
                        p->o_arg.access = NFS4_ACCESS_READ |
                                NFS4_ACCESS_MODIFY |
                                NFS4_ACCESS_EXTEND |
                                NFS4_ACCESS_EXECUTE;
#ifdef CONFIG_NFS_V4_2
                        if (server->caps & NFS_CAP_XATTR)
                                p->o_arg.access |= NFS4_ACCESS_XAREAD |
                                    NFS4_ACCESS_XAWRITE |
                                    NFS4_ACCESS_XALIST;
#endif
                }
        }
        p->o_arg.clientid = server->nfs_client->cl_clientid;
        p->o_arg.id.create_time = ktime_to_ns(sp->so_seqid.create_time);
        p->o_arg.id.uniquifier = sp->so_seqid.owner_id;
        p->o_arg.name = &dentry->d_name;
        p->o_arg.server = server;
        p->o_arg.bitmask = nfs4_bitmask(server, label);
        p->o_arg.open_bitmap = &nfs4_fattr_bitmap[0];
        switch (p->o_arg.claim) {
        case NFS4_OPEN_CLAIM_NULL:
        case NFS4_OPEN_CLAIM_DELEGATE_CUR:
        case NFS4_OPEN_CLAIM_DELEGATE_PREV:
                p->o_arg.fh = NFS_FH(dir);
                break;
        case NFS4_OPEN_CLAIM_PREVIOUS:
        case NFS4_OPEN_CLAIM_FH:
        case NFS4_OPEN_CLAIM_DELEG_CUR_FH:
        case NFS4_OPEN_CLAIM_DELEG_PREV_FH:
                p->o_arg.fh = NFS_FH(d_inode(dentry));
        }
        p->c_arg.fh = &p->o_res.fh;
        p->c_arg.stateid = &p->o_res.stateid;
        p->c_arg.seqid = p->o_arg.seqid;
        nfs4_init_opendata_res(p);
        kref_init(&p->kref);
        return p;

err_free_label:
        nfs4_label_free(p->a_label);
err_free_f:
        nfs4_label_free(p->f_label);
err_free_p:
        kfree(p);
err:
        dput(parent);
        return NULL;
}

static void nfs4_opendata_free(struct kref *kref)
{
        struct nfs4_opendata *p = container_of(kref,
                        struct nfs4_opendata, kref);
        struct super_block *sb = p->dentry->d_sb;

        nfs4_lgopen_release(p->lgp);
        nfs_free_seqid(p->o_arg.seqid);
        nfs4_sequence_free_slot(&p->o_res.seq_res);
        if (p->state != NULL)
                nfs4_put_open_state(p->state);
        nfs4_put_state_owner(p->owner);

        nfs4_label_free(p->a_label);
        nfs4_label_free(p->f_label);

        dput(p->dir);
        dput(p->dentry);
        nfs_sb_deactive(sb);
        nfs_fattr_free_names(&p->f_attr);
        kfree(p->f_attr.mdsthreshold);
        kfree(p);
}

static void nfs4_opendata_put(struct nfs4_opendata *p)
{
        if (p != NULL)
                kref_put(&p->kref, nfs4_opendata_free);
}

static bool nfs4_mode_match_open_stateid(struct nfs4_state *state,
                fmode_t fmode)
{
        switch(fmode & (FMODE_READ|FMODE_WRITE)) {
        case FMODE_READ|FMODE_WRITE:
                return state->n_rdwr != 0;
        case FMODE_WRITE:
                return state->n_wronly != 0;
        case FMODE_READ:
                return state->n_rdonly != 0;
        }
        WARN_ON_ONCE(1);
        return false;
}

static int can_open_cached(struct nfs4_state *state, fmode_t mode,
                int open_mode, enum open_claim_type4 claim)
{
        int ret = 0;

        if (open_mode & (O_EXCL|O_TRUNC))
                goto out;
        switch (claim) {
        case NFS4_OPEN_CLAIM_NULL:
        case NFS4_OPEN_CLAIM_FH:
                goto out;
        default:
                break;
        }
        switch (mode & (FMODE_READ|FMODE_WRITE)) {
                case FMODE_READ:
                        ret |= test_bit(NFS_O_RDONLY_STATE, &state->flags) != 0
                                && state->n_rdonly != 0;
                        break;
                case FMODE_WRITE:
                        ret |= test_bit(NFS_O_WRONLY_STATE, &state->flags) != 0
                                && state->n_wronly != 0;
                        break;
                case FMODE_READ|FMODE_WRITE:
                        ret |= test_bit(NFS_O_RDWR_STATE, &state->flags) != 0
                                && state->n_rdwr != 0;
        }
out:
        return ret;
}

static int can_open_delegated(struct nfs_delegation *delegation, fmode_t fmode,
                enum open_claim_type4 claim)
{
        if (delegation == NULL)
                return 0;
        if ((delegation->type & fmode) != fmode)
                return 0;
        switch (claim) {
        case NFS4_OPEN_CLAIM_NULL:
        case NFS4_OPEN_CLAIM_FH:
                break;
        case NFS4_OPEN_CLAIM_PREVIOUS:
                if (!test_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags))
                        break;
                fallthrough;
        default:
                return 0;
        }
        nfs_mark_delegation_referenced(delegation);
        return 1;
}

static void update_open_stateflags(struct nfs4_state *state, fmode_t fmode)
{
        switch (fmode) {
                case FMODE_WRITE:
                        state->n_wronly++;
                        break;
                case FMODE_READ:
                        state->n_rdonly++;
                        break;
                case FMODE_READ|FMODE_WRITE:
                        state->n_rdwr++;
        }
        nfs4_state_set_mode_locked(state, state->state | fmode);
}

#ifdef CONFIG_NFS_V4_1
static bool nfs_open_stateid_recover_openmode(struct nfs4_state *state)
{
        if (state->n_rdonly && !test_bit(NFS_O_RDONLY_STATE, &state->flags))
                return true;
        if (state->n_wronly && !test_bit(NFS_O_WRONLY_STATE, &state->flags))
                return true;
        if (state->n_rdwr && !test_bit(NFS_O_RDWR_STATE, &state->flags))
                return true;
        return false;
}
#endif /* CONFIG_NFS_V4_1 */

static void nfs_state_log_update_open_stateid(struct nfs4_state *state)
{
        if (test_and_clear_bit(NFS_STATE_CHANGE_WAIT, &state->flags))
                wake_up_all(&state->waitq);
}

static void nfs_test_and_clear_all_open_stateid(struct nfs4_state *state)
{
        struct nfs_client *clp = state->owner->so_server->nfs_client;
        bool need_recover = false;

        if (test_and_clear_bit(NFS_O_RDONLY_STATE, &state->flags) && state->n_rdonly)
                need_recover = true;
        if (test_and_clear_bit(NFS_O_WRONLY_STATE, &state->flags) && state->n_wronly)
                need_recover = true;
        if (test_and_clear_bit(NFS_O_RDWR_STATE, &state->flags) && state->n_rdwr)
                need_recover = true;
        if (need_recover)
                nfs4_state_mark_reclaim_nograce(clp, state);
}

/*
 * Check for whether or not the caller may update the open stateid
 * to the value passed in by stateid.
 *
 * Note: This function relies heavily on the server implementing
 * RFC7530 Section 9.1.4.2, and RFC5661 Section 8.2.2
 * correctly.
 * i.e. The stateid seqids have to be initialised to 1, and
 * are then incremented on every state transition.
 */
static bool nfs_stateid_is_sequential(struct nfs4_state *state,
                const nfs4_stateid *stateid)
{
        if (test_bit(NFS_OPEN_STATE, &state->flags)) {
                /* The common case - we're updating to a new sequence number */
                if (nfs4_stateid_match_other(stateid, &state->open_stateid) &&
                        nfs4_stateid_is_next(&state->open_stateid, stateid)) {
                        return true;
                }
        } else {
                /* This is the first OPEN in this generation */
                if (stateid->seqid == cpu_to_be32(1))
                        return true;
        }
        return false;
}

static void nfs_resync_open_stateid_locked(struct nfs4_state *state)
{
        if (!(state->n_wronly || state->n_rdonly || state->n_rdwr))
                return;
        if (state->n_wronly)
                set_bit(NFS_O_WRONLY_STATE, &state->flags);
        if (state->n_rdonly)
                set_bit(NFS_O_RDONLY_STATE, &state->flags);
        if (state->n_rdwr)
                set_bit(NFS_O_RDWR_STATE, &state->flags);
        set_bit(NFS_OPEN_STATE, &state->flags);
}

static void nfs_clear_open_stateid_locked(struct nfs4_state *state,
                nfs4_stateid *stateid, fmode_t fmode)
{
        clear_bit(NFS_O_RDWR_STATE, &state->flags);
        switch (fmode & (FMODE_READ|FMODE_WRITE)) {
        case FMODE_WRITE:
                clear_bit(NFS_O_RDONLY_STATE, &state->flags);
                break;
        case FMODE_READ:
                clear_bit(NFS_O_WRONLY_STATE, &state->flags);
                break;
        case 0:
                clear_bit(NFS_O_RDONLY_STATE, &state->flags);
                clear_bit(NFS_O_WRONLY_STATE, &state->flags);
                clear_bit(NFS_OPEN_STATE, &state->flags);
        }
        if (stateid == NULL)
                return;
        /* Handle OPEN+OPEN_DOWNGRADE races */
        if (nfs4_stateid_match_other(stateid, &state->open_stateid) &&
            !nfs4_stateid_is_newer(stateid, &state->open_stateid)) {
                nfs_resync_open_stateid_locked(state);
                goto out;
        }
        if (test_bit(NFS_DELEGATED_STATE, &state->flags) == 0)
                nfs4_stateid_copy(&state->stateid, stateid);
        nfs4_stateid_copy(&state->open_stateid, stateid);
        trace_nfs4_open_stateid_update(state->inode, stateid, 0);
out:
        nfs_state_log_update_open_stateid(state);
}

static void nfs_clear_open_stateid(struct nfs4_state *state,
        nfs4_stateid *arg_stateid,
        nfs4_stateid *stateid, fmode_t fmode)
{
        write_seqlock(&state->seqlock);
        /* Ignore, if the CLOSE argment doesn't match the current stateid */
        if (nfs4_state_match_open_stateid_other(state, arg_stateid))
                nfs_clear_open_stateid_locked(state, stateid, fmode);
        write_sequnlock(&state->seqlock);
        if (test_bit(NFS_STATE_RECLAIM_NOGRACE, &state->flags))
                nfs4_schedule_state_manager(state->owner->so_server->nfs_client);
}

static void nfs_set_open_stateid_locked(struct nfs4_state *state,
                const nfs4_stateid *stateid, nfs4_stateid *freeme)
        __must_hold(&state->owner->so_lock)
        __must_hold(&state->seqlock)
        __must_hold(RCU)

{
        DEFINE_WAIT(wait);
        int status = 0;
        for (;;) {

                if (nfs_stateid_is_sequential(state, stateid))
                        break;

                if (status)
                        break;
                /* Rely on seqids for serialisation with NFSv4.0 */
                if (!nfs4_has_session(NFS_SERVER(state->inode)->nfs_client))
                        break;

                set_bit(NFS_STATE_CHANGE_WAIT, &state->flags);
                prepare_to_wait(&state->waitq, &wait, TASK_KILLABLE);
                /*
                 * Ensure we process the state changes in the same order
                 * in which the server processed them by delaying the
                 * update of the stateid until we are in sequence.
                 */
                write_sequnlock(&state->seqlock);
                spin_unlock(&state->owner->so_lock);
                rcu_read_unlock();
                trace_nfs4_open_stateid_update_wait(state->inode, stateid, 0);

                if (!fatal_signal_pending(current)) {
                        if (schedule_timeout(5*HZ) == 0)
                                status = -EAGAIN;
                        else
                                status = 0;
                } else
                        status = -EINTR;
                finish_wait(&state->waitq, &wait);
                rcu_read_lock();
                spin_lock(&state->owner->so_lock);
                write_seqlock(&state->seqlock);
        }

        if (test_bit(NFS_OPEN_STATE, &state->flags) &&
            !nfs4_stateid_match_other(stateid, &state->open_stateid)) {
                nfs4_stateid_copy(freeme, &state->open_stateid);
                nfs_test_and_clear_all_open_stateid(state);
        }

        if (test_bit(NFS_DELEGATED_STATE, &state->flags) == 0)
                nfs4_stateid_copy(&state->stateid, stateid);
        nfs4_stateid_copy(&state->open_stateid, stateid);
        trace_nfs4_open_stateid_update(state->inode, stateid, status);
        nfs_state_log_update_open_stateid(state);
}

static void nfs_state_set_open_stateid(struct nfs4_state *state,
                const nfs4_stateid *open_stateid,
                fmode_t fmode,
                nfs4_stateid *freeme)
{
        /*
         * Protect the call to nfs4_state_set_mode_locked and
         * serialise the stateid update
         */
        write_seqlock(&state->seqlock);
        nfs_set_open_stateid_locked(state, open_stateid, freeme);
        switch (fmode) {
        case FMODE_READ:
                set_bit(NFS_O_RDONLY_STATE, &state->flags);
                break;
        case FMODE_WRITE:
                set_bit(NFS_O_WRONLY_STATE, &state->flags);
                break;
        case FMODE_READ|FMODE_WRITE:
                set_bit(NFS_O_RDWR_STATE, &state->flags);
        }
        set_bit(NFS_OPEN_STATE, &state->flags);
        write_sequnlock(&state->seqlock);
}

static void nfs_state_clear_open_state_flags(struct nfs4_state *state)
{
        clear_bit(NFS_O_RDWR_STATE, &state->flags);
        clear_bit(NFS_O_WRONLY_STATE, &state->flags);
        clear_bit(NFS_O_RDONLY_STATE, &state->flags);
        clear_bit(NFS_OPEN_STATE, &state->flags);
}

static void nfs_state_set_delegation(struct nfs4_state *state,
                const nfs4_stateid *deleg_stateid,
                fmode_t fmode)
{
        /*
         * Protect the call to nfs4_state_set_mode_locked and
         * serialise the stateid update
         */
        write_seqlock(&state->seqlock);
        nfs4_stateid_copy(&state->stateid, deleg_stateid);
        set_bit(NFS_DELEGATED_STATE, &state->flags);
        write_sequnlock(&state->seqlock);
}

static void nfs_state_clear_delegation(struct nfs4_state *state)
{
        write_seqlock(&state->seqlock);
        nfs4_stateid_copy(&state->stateid, &state->open_stateid);
        clear_bit(NFS_DELEGATED_STATE, &state->flags);
        write_sequnlock(&state->seqlock);
}

int update_open_stateid(struct nfs4_state *state,
                const nfs4_stateid *open_stateid,
                const nfs4_stateid *delegation,
                fmode_t fmode)
{
        struct nfs_server *server = NFS_SERVER(state->inode);
        struct nfs_client *clp = server->nfs_client;
        struct nfs_inode *nfsi = NFS_I(state->inode);
        struct nfs_delegation *deleg_cur;
        nfs4_stateid freeme = { };
        int ret = 0;

        fmode &= (FMODE_READ|FMODE_WRITE);

        rcu_read_lock();
        spin_lock(&state->owner->so_lock);
        if (open_stateid != NULL) {
                nfs_state_set_open_stateid(state, open_stateid, fmode, &freeme);
                ret = 1;
        }

        deleg_cur = nfs4_get_valid_delegation(state->inode);
        if (deleg_cur == NULL)
                goto no_delegation;

        spin_lock(&deleg_cur->lock);
        if (rcu_dereference(nfsi->delegation) != deleg_cur ||
           test_bit(NFS_DELEGATION_RETURNING, &deleg_cur->flags) ||
            (deleg_cur->type & fmode) != fmode)
                goto no_delegation_unlock;

        if (delegation == NULL)
                delegation = &deleg_cur->stateid;
        else if (!nfs4_stateid_match_other(&deleg_cur->stateid, delegation))
                goto no_delegation_unlock;

        nfs_mark_delegation_referenced(deleg_cur);
        nfs_state_set_delegation(state, &deleg_cur->stateid, fmode);
        ret = 1;
no_delegation_unlock:
        spin_unlock(&deleg_cur->lock);
no_delegation:
        if (ret)
                update_open_stateflags(state, fmode);
        spin_unlock(&state->owner->so_lock);
        rcu_read_unlock();

        if (test_bit(NFS_STATE_RECLAIM_NOGRACE, &state->flags))
                nfs4_schedule_state_manager(clp);
        if (freeme.type != 0)
                nfs4_test_and_free_stateid(server, &freeme,
                                state->owner->so_cred);

        return ret;
}

static bool nfs4_update_lock_stateid(struct nfs4_lock_state *lsp,
                const nfs4_stateid *stateid)
{
        struct nfs4_state *state = lsp->ls_state;
        bool ret = false;

        spin_lock(&state->state_lock);
        if (!nfs4_stateid_match_other(stateid, &lsp->ls_stateid))
                goto out_noupdate;
        if (!nfs4_stateid_is_newer(stateid, &lsp->ls_stateid))
                goto out_noupdate;
        nfs4_stateid_copy(&lsp->ls_stateid, stateid);
        ret = true;
out_noupdate:
        spin_unlock(&state->state_lock);
        return ret;
}

static void nfs4_return_incompatible_delegation(struct inode *inode, fmode_t fmode)
{
        struct nfs_delegation *delegation;

        fmode &= FMODE_READ|FMODE_WRITE;
        rcu_read_lock();
        delegation = nfs4_get_valid_delegation(inode);
        if (delegation == NULL || (delegation->type & fmode) == fmode) {
                rcu_read_unlock();
                return;
        }
        rcu_read_unlock();
        nfs4_inode_return_delegation(inode);
}

static struct nfs4_state *nfs4_try_open_cached(struct nfs4_opendata *opendata)
{
        struct nfs4_state *state = opendata->state;
        struct nfs_delegation *delegation;
        int open_mode = opendata->o_arg.open_flags;
        fmode_t fmode = opendata->o_arg.fmode;
        enum open_claim_type4 claim = opendata->o_arg.claim;
        nfs4_stateid stateid;
        int ret = -EAGAIN;

        for (;;) {
                spin_lock(&state->owner->so_lock);
                if (can_open_cached(state, fmode, open_mode, claim)) {
                        update_open_stateflags(state, fmode);
                        spin_unlock(&state->owner->so_lock);
                        goto out_return_state;
                }
                spin_unlock(&state->owner->so_lock);
                rcu_read_lock();
                delegation = nfs4_get_valid_delegation(state->inode);
                if (!can_open_delegated(delegation, fmode, claim)) {
                        rcu_read_unlock();
                        break;
                }
                /* Save the delegation */
                nfs4_stateid_copy(&stateid, &delegation->stateid);
                rcu_read_unlock();
                nfs_release_seqid(opendata->o_arg.seqid);
                if (!opendata->is_recover) {
                        ret = nfs_may_open(state->inode, state->owner->so_cred, open_mode);
                        if (ret != 0)
                                goto out;
                }
                ret = -EAGAIN;

                /* Try to update the stateid using the delegation */
                if (update_open_stateid(state, NULL, &stateid, fmode))
                        goto out_return_state;
        }
out:
        return ERR_PTR(ret);
out_return_state:
        refcount_inc(&state->count);
        return state;
}

static void
nfs4_opendata_check_deleg(struct nfs4_opendata *data, struct nfs4_state *state)
{
        struct nfs_client *clp = NFS_SERVER(state->inode)->nfs_client;
        struct nfs_delegation *delegation;
        int delegation_flags = 0;

        rcu_read_lock();
        delegation = rcu_dereference(NFS_I(state->inode)->delegation);
        if (delegation)
                delegation_flags = delegation->flags;
        rcu_read_unlock();
        switch (data->o_arg.claim) {
        default:
                break;
        case NFS4_OPEN_CLAIM_DELEGATE_CUR:
        case NFS4_OPEN_CLAIM_DELEG_CUR_FH:
                pr_err_ratelimited("NFS: Broken NFSv4 server %s is "
                                   "returning a delegation for "
                                   "OPEN(CLAIM_DELEGATE_CUR)\n",
                                   clp->cl_hostname);
                return;
        }
        if ((delegation_flags & 1UL<<NFS_DELEGATION_NEED_RECLAIM) == 0)
                nfs_inode_set_delegation(state->inode,
                                data->owner->so_cred,
                                data->o_res.delegation_type,
                                &data->o_res.delegation,
                                data->o_res.pagemod_limit);
        else
                nfs_inode_reclaim_delegation(state->inode,
                                data->owner->so_cred,
                                data->o_res.delegation_type,
                                &data->o_res.delegation,
                                data->o_res.pagemod_limit);

        if (data->o_res.do_recall)
                nfs_async_inode_return_delegation(state->inode,
                                                  &data->o_res.delegation);
}

/*
 * Check the inode attributes against the CLAIM_PREVIOUS returned attributes
 * and update the nfs4_state.
 */
static struct nfs4_state *
_nfs4_opendata_reclaim_to_nfs4_state(struct nfs4_opendata *data)
{
        struct inode *inode = data->state->inode;
        struct nfs4_state *state = data->state;
        int ret;

        if (!data->rpc_done) {
                if (data->rpc_status)
                        return ERR_PTR(data->rpc_status);
                /* cached opens have already been processed */
                goto update;
        }

        ret = nfs_refresh_inode(inode, &data->f_attr);
        if (ret)
                return ERR_PTR(ret);

        if (data->o_res.delegation_type != 0)
                nfs4_opendata_check_deleg(data, state);
update:
        if (!update_open_stateid(state, &data->o_res.stateid,
                                NULL, data->o_arg.fmode))
                return ERR_PTR(-EAGAIN);
        refcount_inc(&state->count);