s3-winbindd: Fix typo in comment.

[Samba/vl.git] / source3 / modules / onefs_cbrl.c

/*
 * Unix SMB/CIFS implementation.
 * Support for OneFS system interfaces.
 *
 * Copyright (C) Zack Kirsch, 2009
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, see <http://www.gnu.org/licenses/>.
 */

#include "includes.h"
#include "onefs.h"

#include <ifs/ifs_syscalls.h>
#include <sys/isi_cifs_brl.h>
#include <isi_ecs/isi_ecs_cbrl.h>

#undef DBGC_CLASS
#define DBGC_CLASS DBGC_LOCKING

extern struct blocking_lock_record *blocking_lock_queue;

static uint64_t onefs_get_new_id(void) {
        static uint64_t id = 0;

        id++;

        return id;
}

enum onefs_cbrl_lock_state {ONEFS_CBRL_NONE, ONEFS_CBRL_ASYNC, ONEFS_CBRL_DONE,
        ONEFS_CBRL_ERROR};

struct onefs_cbrl_blr_state {
        uint64_t id;
        enum onefs_cbrl_lock_state state;
};

static char *onefs_cbrl_blr_state_str(const struct blocking_lock_record *blr)
{
        static fstring result;
        struct onefs_cbrl_blr_state *bs;

        SMB_ASSERT(blr);

        bs = (struct onefs_cbrl_blr_state *)blr->blr_private;

        if (bs == NULL) {
                fstrcpy(result, "NULL CBRL BLR state - Posix lock?");
                return result;
        }

        switch (bs->state) {
        case ONEFS_CBRL_NONE:
                fstr_sprintf(result, "CBRL BLR id=%llu: state=NONE", bs->id);
                break;
        case ONEFS_CBRL_ASYNC:
                fstr_sprintf(result, "CBRL BLR id=%llu: state=ASYNC", bs->id);
                break;
        case ONEFS_CBRL_DONE:
                fstr_sprintf(result, "CBRL BLR id=%llu: state=DONE", bs->id);
                break;
        case ONEFS_CBRL_ERROR:
                fstr_sprintf(result, "CBRL BLR id=%llu: state=ERROR", bs->id);
                break;
        default:
                fstr_sprintf(result, "CBRL BLR id=%llu: unknown state %d",
                    bs->id, bs->state);
                break;
        }

        return result;
}

static void onefs_cbrl_enumerate_blq(const char *fn)
{
        struct blocking_lock_record *blr;

        if (DEBUGLVL(10))
                return;

        DEBUG(10, ("CBRL BLR records (%s):\n", fn));

        for (blr = blocking_lock_queue; blr; blr = blr->next)
                DEBUGADD(10, ("%s\n", onefs_cbrl_blr_state_str(blr)));
}

static struct blocking_lock_record *onefs_cbrl_find_blr(uint64_t id)
{
        struct blocking_lock_record *blr;
        struct onefs_cbrl_blr_state *bs;

        onefs_cbrl_enumerate_blq("onefs_cbrl_find_blr");

        for (blr = blocking_lock_queue; blr; blr = blr->next) {
                bs = (struct onefs_cbrl_blr_state *)blr->blr_private;

                /* We don't control all of the BLRs on the BLQ. */
                if (bs == NULL)
                        continue;

                if (bs->id == id) {
                        DEBUG(10, ("found %s\n",
                            onefs_cbrl_blr_state_str(blr)));
                        break;
                }
        }

        if (blr == NULL) {
                DEBUG(5, ("Could not find CBRL BLR for id %llu\n", id));
                return NULL;
        }

        return blr;
}

static void onefs_cbrl_async_success(uint64_t id)
{
        struct blocking_lock_record *blr;
        struct onefs_cbrl_blr_state *bs;
        uint16 num_locks;

        DEBUG(10, ("CBRL async success!\n"));

        /* Find BLR with id. Its okay not to find one (race with cancel) */
        blr = onefs_cbrl_find_blr(id);
        if (blr == NULL)
                return;

        bs = (struct onefs_cbrl_blr_state *)blr->blr_private;
        SMB_ASSERT(bs);
        SMB_ASSERT(bs->state == ONEFS_CBRL_ASYNC);

        blr->lock_num++;

        num_locks = SVAL(blr->req->vwv+7, 0);

        if (blr->lock_num == num_locks)
                bs->state = ONEFS_CBRL_DONE;
        else
                bs->state = ONEFS_CBRL_NONE;

        /* Self contend our own level 2 oplock. The kernel handles
         * contention of other opener's level 2 oplocks. */
        contend_level2_oplocks_begin(blr->fsp,
            LEVEL2_CONTEND_WINDOWS_BRL);

        /* Process the queue, to try the next lock or finish up. */
        process_blocking_lock_queue();
}

static void onefs_cbrl_async_failure(uint64_t id)
{
        struct blocking_lock_record *blr;
        struct onefs_cbrl_blr_state *bs;

        DEBUG(10, ("CBRL async failure!\n"));

        /* Find BLR with id. Its okay not to find one (race with cancel) */
        blr = onefs_cbrl_find_blr(id);
        if (blr == NULL)
                return;

        bs = (struct onefs_cbrl_blr_state *)blr->blr_private;
        SMB_ASSERT(bs);

        SMB_ASSERT(bs->state == ONEFS_CBRL_ASYNC);
        bs->state = ONEFS_CBRL_ERROR;

        /* Process the queue. It will end up trying to retake the same lock,
         * see the error in onefs_cbrl_lock_windows() and fail. */
        process_blocking_lock_queue();
}

static struct cbrl_event_ops cbrl_ops =
    {.cbrl_async_success = onefs_cbrl_async_success,
     .cbrl_async_failure = onefs_cbrl_async_failure};
 
static void onefs_cbrl_events_handler(struct event_context *ev,
                                        struct fd_event *fde,
                                        uint16_t flags,
                                        void *private_data)
{
        DEBUG(10, ("onefs_cbrl_events_handler\n"));

        if (cbrl_event_dispatcher(&cbrl_ops)) {
                DEBUG(0, ("cbrl_event_dispatcher failed: %s\n",
                        strerror(errno)));
        }
}

static void onefs_init_cbrl(void)
{
        static bool init_done = false;
        static int cbrl_event_fd;
        static struct fd_event *cbrl_fde;

        if (init_done)
                return;

        DEBUG(10, ("onefs_init_cbrl\n"));

        /* Register the event channel for CBRL. */
        cbrl_event_fd = cbrl_event_register();
        if (cbrl_event_fd == -1) {
                DEBUG(0, ("cbrl_event_register failed: %s\n",
                        strerror(errno)));
                return;
        }

        DEBUG(10, ("cbrl_event_fd = %d\n", cbrl_event_fd));

        /* Register the CBRL event_fd with samba's event system */
        cbrl_fde = event_add_fd(smbd_event_context(),
                                     NULL,
                                     cbrl_event_fd,
                                     EVENT_FD_READ,
                                     onefs_cbrl_events_handler,
                                     NULL);

        init_done = true;
        return;
}

/**
 * Blocking PID. As far as I can tell, the blocking_pid is only used to tell
 * whether a posix lock or a CIFS lock blocked us. If it was a posix lock,
 * Samba polls every 10 seconds, which we don't want. -zkirsch
 */
#define ONEFS_BLOCKING_PID 0xABCDABCD

/**
 * @param[in]     br_lck        Contains the fsp.
 * @param[in]     plock         Lock request.
 * @param[in]     blocking_lock Only used for figuring out the error.
 * @param[in,out] blr           The BLR for the already-deferred operation.
 */
NTSTATUS onefs_brl_lock_windows(vfs_handle_struct *handle,
                                struct byte_range_lock *br_lck,
                                struct lock_struct *plock,
                                bool blocking_lock,
                                struct blocking_lock_record *blr)
{
        int fd = br_lck->fsp->fh->fd;
        uint64_t id = 0;
        enum cbrl_lock_type type;
        bool async = false;
        bool pending = false;
        bool pending_async = false;
        int error;
        struct onefs_cbrl_blr_state *bs;
        NTSTATUS status;

        START_PROFILE(syscall_brl_lock);

        SMB_ASSERT(plock->lock_flav == WINDOWS_LOCK);
        SMB_ASSERT(plock->lock_type != UNLOCK_LOCK);

        onefs_cbrl_enumerate_blq("onefs_brl_lock_windows");

        /* Will only initialize the first time its called. */
        onefs_init_cbrl();

        switch (plock->lock_type) {
                case WRITE_LOCK:
                        type = CBRL_LK_EX;
                        break;
                case READ_LOCK:
                        type = CBRL_LK_SH;
                        break;
                case PENDING_WRITE_LOCK:
                        /* Called when a blocking lock request is added - do an
                         * async lock. */
                        type = CBRL_LK_EX;
                        pending = true;
                        async = true;
                        break;
                case PENDING_READ_LOCK:
                        /* Called when a blocking lock request is added - do an
                         * async lock. */
                        type = CBRL_LK_SH;
                        pending = true;
                        async = true;
                        break;
                default:
                        /* UNLOCK_LOCK: should only be used for a POSIX_LOCK */
                        smb_panic("Invalid plock->lock_type passed in to "
                            "onefs_brl_lock_windows");
        }

        /* Figure out if we're actually doing the lock or a no-op. We need to
         * do a no-op when process_blocking_lock_queue calls back into us.
         *
         * We know process_* is calling into us if a blr is passed in and
         * pending is false. */
        if (!pending && blr) {
                /* Check the BLR state. */
                bs = (struct onefs_cbrl_blr_state *)blr->blr_private;
                SMB_ASSERT(bs);

                /* ASYNC still in progress: The process_* calls will keep
                 * calling even if we haven't gotten the lock. Keep erroring
                 * without calling ifs_cbrl, or getting/setting an id. */
                if (bs->state == ONEFS_CBRL_ASYNC) {
                        goto failure;
                }
                else if (bs->state == ONEFS_CBRL_ERROR) {
                        END_PROFILE(syscall_brl_lock);
                        return NT_STATUS_NO_MEMORY;
                }

                SMB_ASSERT(bs->state == ONEFS_CBRL_NONE);
                async = true;
        }

        if (async) {
                SMB_ASSERT(blocking_lock);
                SMB_ASSERT(blr);
                id = onefs_get_new_id();
        }

        DEBUG(10, ("Calling ifs_cbrl(LOCK)...\n"));
        error = ifs_cbrl(fd, CBRL_OP_LOCK, type, plock->start,
            plock->size, async, id, plock->context.smbpid, plock->context.tid,
            plock->fnum);
        if (!error) {
                goto success;
        } else if (errno == EWOULDBLOCK) {
                SMB_ASSERT(!async);
        } else if (errno == EINPROGRESS) {
                SMB_ASSERT(async);

                if (pending) {
                        /* Talloc a new BLR private state. */
                        blr->blr_private = talloc(blr, struct onefs_cbrl_blr_state);
                        pending_async = true;
                }

                /* Store the new id in the BLR private state. */
                bs = (struct onefs_cbrl_blr_state *)blr->blr_private;
                bs->id = id;
                bs->state = ONEFS_CBRL_ASYNC;
        } else {
                DEBUG(0, ("onefs_brl_lock_windows failure: error=%d (%s).\n",
                        errno, strerror(errno)));
        }

failure:

        END_PROFILE(syscall_brl_lock);

        /* Failure - error or async. */
        plock->context.smbpid = (uint32) ONEFS_BLOCKING_PID;

        if (pending_async)
                status = NT_STATUS_OK;
        else
                status = brl_lock_failed(br_lck->fsp, plock, blocking_lock);

        DEBUG(10, ("returning %s.\n", nt_errstr(status)));
        return status;

success:
        /* Self contend our own level 2 oplock. The kernel handles
         * contention of other opener's level 2 oplocks. */
        contend_level2_oplocks_begin(br_lck->fsp,
            LEVEL2_CONTEND_WINDOWS_BRL);

        END_PROFILE(syscall_brl_lock);

        /* Success. */
        onefs_cbrl_enumerate_blq("onefs_brl_unlock_windows");
        DEBUG(10, ("returning NT_STATUS_OK.\n"));
        return NT_STATUS_OK;
}

bool onefs_brl_unlock_windows(vfs_handle_struct *handle,
                              struct messaging_context *msg_ctx,
                              struct byte_range_lock *br_lck,
                              const struct lock_struct *plock)
{
        int error;
        int fd = br_lck->fsp->fh->fd;

        START_PROFILE(syscall_brl_unlock);

        SMB_ASSERT(plock->lock_flav == WINDOWS_LOCK);
        SMB_ASSERT(plock->lock_type == UNLOCK_LOCK);

        DEBUG(10, ("Calling ifs_cbrl(UNLOCK)...\n"));
        error = ifs_cbrl(fd, CBRL_OP_UNLOCK, CBRL_LK_SH,
            plock->start, plock->size, false, 0, plock->context.smbpid,
            plock->context.tid, plock->fnum);

        END_PROFILE(syscall_brl_unlock);

        if (error) {
                DEBUG(10, ("returning false.\n"));
                return false;
        }

        /* For symmetry purposes, end our oplock contention even though its
         * currently a no-op. */
        contend_level2_oplocks_end(br_lck->fsp, LEVEL2_CONTEND_WINDOWS_BRL);

        DEBUG(10, ("returning true.\n"));
        return true;

        /* Problem with storing things in TDB: I won't know what BRL to unlock in the TDB.
         *  - I could fake it?
         *  - I could send Samba a message with which lock is being unlocked?
         *  - I could *easily* make the "id" something you always pass in to
         *  lock, unlock or cancel -- it identifies a lock. Makes sense!
         */
}

/* Default implementation only calls this on PENDING locks. */
bool onefs_brl_cancel_windows(vfs_handle_struct *handle,
                              struct byte_range_lock *br_lck,
                              struct lock_struct *plock,
                              struct blocking_lock_record *blr)
{
        int error;
        int fd = br_lck->fsp->fh->fd;
        struct onefs_cbrl_blr_state *bs;

        START_PROFILE(syscall_brl_cancel);

        SMB_ASSERT(plock);
        SMB_ASSERT(plock->lock_flav == WINDOWS_LOCK);
        SMB_ASSERT(blr);

        onefs_cbrl_enumerate_blq("onefs_brl_cancel_windows");

        bs = ((struct onefs_cbrl_blr_state *)blr->blr_private);
        SMB_ASSERT(bs);

        if (bs->state == ONEFS_CBRL_DONE || bs->state == ONEFS_CBRL_ERROR) {
                /* No-op. */
                DEBUG(10, ("State=%d, returning true\n", bs->state));
                END_PROFILE(syscall_brl_cancel);
                return true;
        }

        SMB_ASSERT(bs->state == ONEFS_CBRL_NONE ||
            bs->state == ONEFS_CBRL_ASYNC);

        /* A real cancel. */
        DEBUG(10, ("Calling ifs_cbrl(CANCEL)...\n"));
        error = ifs_cbrl(fd, CBRL_OP_CANCEL, CBRL_LK_UNSPEC, plock->start,
            plock->size, false, bs->id, plock->context.smbpid,
            plock->context.tid, plock->fnum);

        END_PROFILE(syscall_brl_cancel);

        if (error) {
                DEBUG(10, ("returning false\n"));
                bs->state = ONEFS_CBRL_ERROR;
                return false;
        }

        bs->state = ONEFS_CBRL_DONE;
        onefs_cbrl_enumerate_blq("onefs_brl_cancel_windows");
        DEBUG(10, ("returning true\n"));
        return true;
}

bool onefs_strict_lock(vfs_handle_struct *handle,
                        files_struct *fsp,
                        struct lock_struct *plock)
{
        int error;

        START_PROFILE(syscall_strict_lock);

        SMB_ASSERT(plock->lock_type == READ_LOCK ||
            plock->lock_type == WRITE_LOCK);

        if (!lp_locking(handle->conn->params) ||
            !lp_strict_locking(handle->conn->params)) {
                END_PROFILE(syscall_strict_lock);
                return True;
        }

        if (plock->lock_flav == POSIX_LOCK) {
                END_PROFILE(syscall_strict_lock);
                return SMB_VFS_NEXT_STRICT_LOCK(handle, fsp, plock);
        }

        if (plock->size == 0) {
                END_PROFILE(syscall_strict_lock);
                return True;
        }

        error = ifs_cbrl(fsp->fh->fd, CBRL_OP_LOCK,
            plock->lock_type == READ_LOCK ? CBRL_LK_RD : CBRL_LK_WR,
            plock->start, plock->size, 0, 0, plock->context.smbpid,
            plock->context.tid, plock->fnum);

        END_PROFILE(syscall_strict_lock);

        return (error == 0);
}

void onefs_strict_unlock(vfs_handle_struct *handle,
                        files_struct *fsp,
                        struct lock_struct *plock)
{
        START_PROFILE(syscall_strict_unlock);

        SMB_ASSERT(plock->lock_type == READ_LOCK ||
            plock->lock_type == WRITE_LOCK);

        if (!lp_locking(handle->conn->params) ||
            !lp_strict_locking(handle->conn->params)) {
                END_PROFILE(syscall_strict_unlock);
                return;
        }

        if (plock->lock_flav == POSIX_LOCK) {
                SMB_VFS_NEXT_STRICT_UNLOCK(handle, fsp, plock);
                END_PROFILE(syscall_strict_unlock);
                return;
        }

        if (plock->size == 0) {
                END_PROFILE(syscall_strict_unlock);
                return;
        }

        if (fsp->fh) {
                ifs_cbrl(fsp->fh->fd, CBRL_OP_UNLOCK,
                    plock->lock_type == READ_LOCK ? CBRL_LK_RD : CBRL_LK_WR,
                    plock->start, plock->size, 0, 0, plock->context.smbpid,
                    plock->context.tid, plock->fnum);
        }

        END_PROFILE(syscall_strict_unlock);
}

/* TODO Optimization: Abstract out brl_get_locks() in the Windows case.
 * We'll malloc some memory or whatever (can't return NULL), but not actually
 * touch the TDB. */

/* XXX brl_locktest: CBRL does not support calling this, but its only for
 * strict locking. Add empty VOP? */

/* XXX brl_lockquery: CBRL does not support calling this for WINDOWS LOCKS, but
 * its only called for POSIX LOCKS. Add empty VOP? */

/* XXX brl_close_fnum: CBRL will do this automatically. I think this is a NO-OP
 * for us, we could add an empty VOP. */