/*
 * Copyright (c) 2000-2001, Boris Popov
 * All rights reserved.
 *
 * 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *    This product includes software developed by Boris Popov.
 * 4. Neither the name of the author nor the names of any co-contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``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 AUTHOR 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.
 *
 * $FreeBSD: src/sys/fs/smbfs/smbfs_io.c,v 1.3.2.3 2003/01/17 08:20:26 tjr Exp $
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/uio.h>
#include <sys/resourcevar.h>    /* defines plimit structure in proc struct */
#include <sys/kernel.h>
#include <sys/proc.h>
#include <sys/fcntl.h>
#include <sys/mount.h>
#include <sys/vnode.h>
#include <sys/dirent.h>
#include <sys/signalvar.h>
#include <sys/sysctl.h>

#include  <machine/limits.h>

#include <vm/vm.h>
#include <vm/vm_page2.h>
#include <vm/vm_extern.h>
#include <vm/vm_object.h>
#include <vm/vm_pager.h>
#include <vm/vnode_pager.h>

#include <netproto/smb/smb.h>
#include <netproto/smb/smb_conn.h>
#include <netproto/smb/smb_subr.h>

#include "smbfs.h"
#include "smbfs_node.h"
#include "smbfs_subr.h"

#include <sys/buf.h>

#include <sys/thread2.h>

/*#define SMBFS_RWGENERIC*/

extern int smbfs_pbuf_freecnt;

static int smbfs_fastlookup = 1;

SYSCTL_DECL(_vfs_smbfs);
SYSCTL_INT(_vfs_smbfs, OID_AUTO, fastlookup, CTLFLAG_RW, &smbfs_fastlookup, 0, "");

static int
smbfs_readvdir(struct vnode *vp, struct uio *uio, struct ucred *cred)
{
        struct smb_cred scred;
        struct smbfs_fctx *ctx;
        struct vnode *newvp;
        struct smbnode *np;
        int error, offset, retval;

        np = VTOSMB(vp);
        SMBVDEBUG("dirname='%s'\n", np->n_name);
        smb_makescred(&scred, uio->uio_td, cred);

        if (uio->uio_offset < 0 || uio->uio_offset > INT_MAX)
                return(EINVAL);

        error = 0;
        offset = uio->uio_offset;

        if (uio->uio_resid > 0 && offset < 1) {
                if (vop_write_dirent(&error, uio, np->n_ino, DT_DIR, 1, "."))
                        goto done;
                if (error)
                        goto done;
                ++offset;
        }

        if (uio->uio_resid > 0 && offset < 2) {
                if (vop_write_dirent(&error, uio,
                    np->n_parent ? VTOSMB(np->n_parent)->n_ino : 2,
                    DT_DIR, 2, ".."))
                        goto done;
                if (error)
                        goto done;
                ++offset;
        }

        if (uio->uio_resid == 0)
                goto done;

        if (offset != np->n_dirofs || np->n_dirseq == NULL) {
                SMBVDEBUG("Reopening search %ld:%ld\n", offset, np->n_dirofs);
                if (np->n_dirseq) {
                        smbfs_findclose(np->n_dirseq, &scred);
                        np->n_dirseq = NULL;
                }
                np->n_dirofs = 2;
                error = smbfs_findopen(np, "*", 1,
                    SMB_FA_SYSTEM | SMB_FA_HIDDEN | SMB_FA_DIR,
                    &scred, &ctx);
                if (error) {
                        SMBVDEBUG("can not open search, error = %d", error);
                        return error;
                }
                np->n_dirseq = ctx;
        } else {
                ctx = np->n_dirseq;
        }
        while (np->n_dirofs < offset) {
                error = smbfs_findnext(ctx, offset - np->n_dirofs, &scred);
                ++np->n_dirofs;
                if (error) {
                        smbfs_findclose(np->n_dirseq, &scred);
                        np->n_dirseq = NULL;
                        return error == ENOENT ? 0 : error;
                }
        }
        error = 0;
        while (uio->uio_resid > 0 && !error) {
                /*
                 * Overestimate the size of a record a bit, doesn't really
                 * hurt to be wrong here.
                 */
                error = smbfs_findnext(ctx, uio->uio_resid / _DIRENT_RECLEN(255) + 1, &scred);
                if (error)
                        break;
                np->n_dirofs++;
                ++offset;

                retval = vop_write_dirent(&error, uio, ctx->f_attr.fa_ino,
                    (ctx->f_attr.fa_attr & SMB_FA_DIR) ? DT_DIR : DT_REG,
                    ctx->f_nmlen, ctx->f_name);
                if (retval)
                        break;
                if (smbfs_fastlookup && !error) {
                        error = smbfs_nget(vp->v_mount, vp, ctx->f_name,
                            ctx->f_nmlen, &ctx->f_attr, &newvp);
                        if (!error)
                                vput(newvp);
                }
        }
        if (error == ENOENT)
                error = 0;
done:
        uio->uio_offset = offset;
        return error;
}

int
smbfs_readvnode(struct vnode *vp, struct uio *uiop, struct ucred *cred)
{
        struct thread *td;
        struct smbmount *smp = VFSTOSMBFS(vp->v_mount);
        struct smbnode *np = VTOSMB(vp);
        struct vattr vattr;
        struct smb_cred scred;
        int error, lks;

        /*
         * Protect against method which is not supported for now
         */
        if (uiop->uio_segflg == UIO_NOCOPY)
                return EOPNOTSUPP;

        if (vp->v_type != VREG && vp->v_type != VDIR) {
                SMBFSERR("vn types other than VREG or VDIR are unsupported !\n");
                return EIO;
        }
        if (uiop->uio_resid == 0)
                return 0;
        if (uiop->uio_offset < 0)
                return EINVAL;
        td = uiop->uio_td;
        if (vp->v_type == VDIR) {
                lks = LK_EXCLUSIVE;/*lockstatus(&vp->v_lock, td);*/
                if (lks == LK_SHARED)
                        vn_lock(vp, LK_UPGRADE | LK_RETRY);
                error = smbfs_readvdir(vp, uiop, cred);
                if (lks == LK_SHARED)
                        vn_lock(vp, LK_DOWNGRADE | LK_RETRY);
                return error;
        }

/*      biosize = SSTOCN(smp->sm_share)->sc_txmax;*/
        if (np->n_flag & NMODIFIED) {
                smbfs_attr_cacheremove(vp);
                error = VOP_GETATTR(vp, &vattr);
                if (error)
                        return error;
                np->n_mtime.tv_sec = vattr.va_mtime.tv_sec;
        } else {
                error = VOP_GETATTR(vp, &vattr);
                if (error)
                        return error;
                if (np->n_mtime.tv_sec != vattr.va_mtime.tv_sec) {
                        error = smbfs_vinvalbuf(vp, V_SAVE, 1);
                        if (error)
                                return error;
                        np->n_mtime.tv_sec = vattr.va_mtime.tv_sec;
                }
        }
        smb_makescred(&scred, td, cred);
        return smb_read(smp->sm_share, np->n_fid, uiop, &scred);
}

int
smbfs_writevnode(struct vnode *vp, struct uio *uiop,
                 struct ucred *cred, int ioflag)
{
        struct thread *td;
        struct smbmount *smp = VTOSMBFS(vp);
        struct smbnode *np = VTOSMB(vp);
        struct smb_cred scred;
        int error = 0;

        if (vp->v_type != VREG) {
                SMBERROR("vn types other than VREG unsupported !\n");
                return EIO;
        }
        SMBVDEBUG("ofs=%d,resid=%d\n",(int)uiop->uio_offset, uiop->uio_resid);
        if (uiop->uio_offset < 0)
                return EINVAL;
        td = uiop->uio_td;
        if (ioflag & (IO_APPEND | IO_SYNC)) {
                if (np->n_flag & NMODIFIED) {
                        smbfs_attr_cacheremove(vp);
                        error = smbfs_vinvalbuf(vp, V_SAVE, 1);
                        if (error)
                                return error;
                }
                if (ioflag & IO_APPEND) {
#if 0 /* notyet */
                        /*
                         * File size can be changed by another client
                         */
                        smbfs_attr_cacheremove(vp);
                        error = VOP_GETATTR(vp, &vattr);
                        if (error) return (error);
#endif
                        uiop->uio_offset = np->n_size;
                }
        }
        if (uiop->uio_resid == 0)
                return 0;
        if (td->td_proc &&
            uiop->uio_offset + uiop->uio_resid >
            td->td_proc->p_rlimit[RLIMIT_FSIZE].rlim_cur) {
                lwpsignal(td->td_proc, td->td_lwp, SIGXFSZ);
                return EFBIG;
        }
        smb_makescred(&scred, td, cred);
        error = smb_write(smp->sm_share, np->n_fid, uiop, &scred);
        SMBVDEBUG("after: ofs=%d,resid=%d\n",(int)uiop->uio_offset, uiop->uio_resid);
        if (!error) {
                if (uiop->uio_offset > np->n_size) {
                        np->n_size = uiop->uio_offset;
                        vnode_pager_setsize(vp, np->n_size);
                }
        }
        return error;
}

/*
 * Do an I/O operation to/from a cache block.
 */
int
smbfs_doio(struct vnode *vp, struct bio *bio, struct ucred *cr, struct thread *td)
{
        struct buf *bp = bio->bio_buf;
        struct smbmount *smp = VFSTOSMBFS(vp->v_mount);
        struct smbnode *np = VTOSMB(vp);
        struct uio uio, *uiop = &uio;
        struct iovec io;
        struct smb_cred scred;
        int error = 0;

        uiop->uio_iov = &io;
        uiop->uio_iovcnt = 1;
        uiop->uio_segflg = UIO_SYSSPACE;
        uiop->uio_td = td;

        smb_makescred(&scred, td, cr);

        if (bp->b_cmd == BUF_CMD_READ) {
            io.iov_len = uiop->uio_resid = (size_t)bp->b_bcount;
            io.iov_base = bp->b_data;
            uiop->uio_rw = UIO_READ;
            switch (vp->v_type) {
              case VREG:
                uiop->uio_offset = bio->bio_offset;
                error = smb_read(smp->sm_share, np->n_fid, uiop, &scred);
                if (error)
                        break;
                if (uiop->uio_resid) {
                        size_t left = uiop->uio_resid;
                        size_t nread = (size_t)bp->b_bcount - left;
                        if (left > 0)
                                bzero((char *)bp->b_data + nread, left);
                }
                break;
            default:
                kprintf("smbfs_doio:  type %x unexpected\n",vp->v_type);
                break;
            }
            if (error) {
                bp->b_error = error;
                bp->b_flags |= B_ERROR;
            }
        } else { /* write */
            KKASSERT(bp->b_cmd == BUF_CMD_WRITE);
            if (bio->bio_offset + bp->b_dirtyend > np->n_size)
                bp->b_dirtyend = np->n_size - bio->bio_offset;

            if (bp->b_dirtyend > bp->b_dirtyoff) {
                io.iov_len = uiop->uio_resid =
                        (size_t)(bp->b_dirtyend - bp->b_dirtyoff);
                uiop->uio_offset = bio->bio_offset + bp->b_dirtyoff;
                io.iov_base = (char *)bp->b_data + bp->b_dirtyoff;
                uiop->uio_rw = UIO_WRITE;
                error = smb_write(smp->sm_share, np->n_fid, uiop, &scred);

                /*
                 * For an interrupted write, the buffer is still valid
                 * and the write hasn't been pushed to the server yet,
                 * so we can't set BIO_ERROR and report the interruption
                 * by setting B_EINTR. For the async case, B_EINTR
                 * is not relevant, so the rpc attempt is essentially
                 * a noop.  For the case of a V3 write rpc not being
                 * committed to stable storage, the block is still
                 * dirty and requires either a commit rpc or another
                 * write rpc with iomode == NFSV3WRITE_FILESYNC before
                 * the block is reused. This is indicated by setting
                 * the B_DELWRI and B_NEEDCOMMIT flags.
                 */
                if (error == EINTR
                    || (!error && (bp->b_flags & B_NEEDCOMMIT))) {

                        crit_enter();
                        bp->b_flags &= ~(B_INVAL|B_NOCACHE);
                        if ((bp->b_flags & B_PAGING) == 0)
                            bdirty(bp);
                        bp->b_flags |= B_EINTR;
                        crit_exit();
                } else {
                        if (error) {
                                bp->b_flags |= B_ERROR;
                                bp->b_error = error;
                        }
                        bp->b_dirtyoff = bp->b_dirtyend = 0;
                }
            } else {
                bp->b_resid = 0;
                biodone(bio);
                return 0;
            }
        }
        bp->b_resid = uiop->uio_resid;
        biodone(bio);
        return error;
}

/*
 * Vnode op for VM getpages.
 * Wish wish .... get rid from multiple IO routines
 *
 * smbfs_getpages(struct vnode *a_vp, vm_page_t *a_m, int a_count,
 *                int a_reqpage, vm_ooffset_t a_offset)
 */
int
smbfs_getpages(struct vop_getpages_args *ap)
{
#ifdef SMBFS_RWGENERIC
        return vop_stdgetpages(ap);
#else
        int i, error, npages;
        int doclose;
        size_t size, toff, nextoff, count;
        struct uio uio;
        struct iovec iov;
        vm_offset_t kva;
        struct buf *bp;
        struct vnode *vp;
        struct thread *td = curthread;  /* XXX */
        struct ucred *cred;
        struct smbmount *smp;
        struct smbnode *np;
        struct smb_cred scred;
        vm_page_t *pages;

        KKASSERT(td->td_proc);

        vp = ap->a_vp;
        cred = td->td_proc->p_ucred;
        np = VTOSMB(vp);
        smp = VFSTOSMBFS(vp->v_mount);
        pages = ap->a_m;
        count = (size_t)ap->a_count;

        if (vp->v_object == NULL) {
                kprintf("smbfs_getpages: called with non-merged cache vnode??\n");
                return VM_PAGER_ERROR;
        }
        smb_makescred(&scred, td, cred);

        bp = getpbuf_kva(&smbfs_pbuf_freecnt);
        npages = btoc(count);
        kva = (vm_offset_t) bp->b_data;
        pmap_qenter(kva, pages, npages);

        iov.iov_base = (caddr_t) kva;
        iov.iov_len = count;
        uio.uio_iov = &iov;
        uio.uio_iovcnt = 1;
        uio.uio_offset = IDX_TO_OFF(pages[0]->pindex);
        uio.uio_resid = count;
        uio.uio_segflg = UIO_SYSSPACE;
        uio.uio_rw = UIO_READ;
        uio.uio_td = td;

        /*
         * This is kinda nasty.  Since smbfs is physically closing the
         * fid on close(), we have to reopen it if necessary.  There are
         * other races here too, such as if another process opens the same
         * file while we are blocked in read. XXX
         */
        error = 0;
        doclose = 0;
        if (np->n_opencount == 0) {
                error = smbfs_smb_open(np, SMB_AM_OPENREAD, &scred);
                if (error == 0)
                        doclose = 1;
        }
        if (error == 0)
                error = smb_read(smp->sm_share, np->n_fid, &uio, &scred);
        if (doclose)
                smbfs_smb_close(smp->sm_share, np->n_fid, NULL, &scred);
        pmap_qremove(kva, npages);

        relpbuf(bp, &smbfs_pbuf_freecnt);

        if (error && (uio.uio_resid == count)) {
                kprintf("smbfs_getpages: error %d\n",error);
                for (i = 0; i < npages; i++) {
                        if (ap->a_reqpage != i)
                                vnode_pager_freepage(pages[i]);
                }
                return VM_PAGER_ERROR;
        }

        size = count - uio.uio_resid;

        for (i = 0, toff = 0; i < npages; i++, toff = nextoff) {
                vm_page_t m;
                nextoff = toff + PAGE_SIZE;
                m = pages[i];

                /*
                 * NOTE: pmap dirty bit should have already been cleared.
                 *       We do not clear it here.
                 */
                if (nextoff <= size) {
                        m->valid = VM_PAGE_BITS_ALL;
                        m->dirty = 0;
                } else {
                        int nvalid = rounddown2((size + DEV_BSIZE - 1) - toff,
                            DEV_BSIZE);
                        vm_page_set_validclean(m, 0, nvalid);
                }
                
                if (i != ap->a_reqpage) {
                        /*
                         * Whether or not to leave the page activated is up in
                         * the air, but we should put the page on a page queue
                         * somewhere (it already is in the object).  Result:
                         * It appears that emperical results show that
                         * deactivating pages is best.
                         */

                        /*
                         * Just in case someone was asking for this page we
                         * now tell them that it is ok to use.
                         */
                        if (!error) {
                                if (m->flags & PG_REFERENCED)
                                        vm_page_activate(m);
                                else
                                        vm_page_deactivate(m);
                                vm_page_wakeup(m);
                        } else {
                                vnode_pager_freepage(m);
                        }
                }
        }
        return 0;
#endif /* SMBFS_RWGENERIC */
}

/*
 * Vnode op for VM putpages.
 * possible bug: all IO done in sync mode
 * Note that vop_close always invalidate pages before close, so it's
 * not necessary to open vnode.
 *
 * smbfs_putpages(struct vnode *a_vp, vm_page_t *a_m, int a_count, int a_flags,
 *                int *a_rtvals, vm_ooffset_t a_offset)
 */
int
smbfs_putpages(struct vop_putpages_args *ap)
{
        int error;
        struct vnode *vp = ap->a_vp;
        struct thread *td = curthread;  /* XXX */
        struct ucred *cred;

#ifdef SMBFS_RWGENERIC
        KKASSERT(td->td_proc);
        cred = td->td_proc->p_ucred;
        VOP_OPEN(vp, FWRITE, cred, NULL);
        error = vop_stdputpages(ap);
        VOP_CLOSE(vp, FWRITE, cred, NULL);
        return error;
#else
        struct uio uio;
        struct iovec iov;
        vm_offset_t kva;
        struct buf *bp;
        int i, npages, count;
        int doclose;
        int *rtvals;
        struct smbmount *smp;
        struct smbnode *np;
        struct smb_cred scred;
        vm_page_t *pages;

        KKASSERT(td->td_proc);
        cred = td->td_proc->p_ucred;
/*      VOP_OPEN(vp, FWRITE, cred, NULL);*/
        np = VTOSMB(vp);
        smp = VFSTOSMBFS(vp->v_mount);
        pages = ap->a_m;
        count = ap->a_count;
        rtvals = ap->a_rtvals;
        npages = btoc(count);

        for (i = 0; i < npages; i++) {
                rtvals[i] = VM_PAGER_AGAIN;
        }

        bp = getpbuf_kva(&smbfs_pbuf_freecnt);
        kva = (vm_offset_t) bp->b_data;
        pmap_qenter(kva, pages, npages);

        iov.iov_base = (caddr_t) kva;
        iov.iov_len = count;
        uio.uio_iov = &iov;
        uio.uio_iovcnt = 1;
        uio.uio_offset = IDX_TO_OFF(pages[0]->pindex);
        uio.uio_resid = count;
        uio.uio_segflg = UIO_SYSSPACE;
        uio.uio_rw = UIO_WRITE;
        uio.uio_td = td;
        SMBVDEBUG("ofs=%d,resid=%d\n",(int)uio.uio_offset, uio.uio_resid);

        smb_makescred(&scred, td, cred);

        /*
         * This is kinda nasty.  Since smbfs is physically closing the
         * fid on close(), we have to reopen it if necessary.  There are
         * other races here too, such as if another process opens the same
         * file while we are blocked in read, or the file is open read-only
         * XXX
         */
        error = 0;
        doclose = 0;
        if (np->n_opencount == 0) {
                error = smbfs_smb_open(np, SMB_AM_OPENRW, &scred);
                if (error == 0)
                        doclose = 1;
        }
        if (error == 0)
                error = smb_write(smp->sm_share, np->n_fid, &uio, &scred);
        if (doclose)
                smbfs_smb_close(smp->sm_share, np->n_fid, NULL, &scred);
/*      VOP_CLOSE(vp, FWRITE, cred);*/
        SMBVDEBUG("paged write done: %d\n", error);

        pmap_qremove(kva, npages);
        relpbuf(bp, &smbfs_pbuf_freecnt);

        if (!error) {
                int nwritten = round_page(count - uio.uio_resid) / PAGE_SIZE;
                for (i = 0; i < nwritten; i++) {
                        rtvals[i] = VM_PAGER_OK;
                        vm_page_undirty(pages[i]);
                }
        }
        return rtvals[0];
#endif /* SMBFS_RWGENERIC */
}

/*
 * Flush and invalidate all dirty buffers. If another process is already
 * doing the flush, just wait for completion.
 */
int
smbfs_vinvalbuf(struct vnode *vp, int flags, int intrflg)
{
        struct smbnode *np = VTOSMB(vp);
        int error = 0, slpflag, slptimeo;

        if (vp->v_flag & VRECLAIMED)
                return 0;
        if (intrflg) {
                slpflag = PCATCH;
                slptimeo = 2 * hz;
        } else {
                slpflag = 0;
                slptimeo = 0;
        }
        while (np->n_flag & NFLUSHINPROG) {
                np->n_flag |= NFLUSHWANT;
                error = tsleep((caddr_t)&np->n_flag, 0, "smfsvinv", slptimeo);
                error = smb_proc_intr(curthread);
                if (error == EINTR && intrflg)
                        return EINTR;
        }
        np->n_flag |= NFLUSHINPROG;
        error = vinvalbuf(vp, flags, slpflag, 0);
        while (error) {
                if (intrflg && (error == ERESTART || error == EINTR)) {
                        np->n_flag &= ~NFLUSHINPROG;
                        if (np->n_flag & NFLUSHWANT) {
                                np->n_flag &= ~NFLUSHWANT;
                                wakeup((caddr_t)&np->n_flag);
                        }
                        return EINTR;
                }
                error = vinvalbuf(vp, flags, slpflag, 0);
        }
        np->n_flag &= ~(NMODIFIED | NFLUSHINPROG);
        if (np->n_flag & NFLUSHWANT) {
                np->n_flag &= ~NFLUSHWANT;
                wakeup((caddr_t)&np->n_flag);
        }
        return (error);
}