/*
 * Copyright (c) 1982, 1986, 1989, 1993
 *      The Regents of the University of California.  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. 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 BY THE REGENTS 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 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.
 *
 *      @(#)ffs_balloc.c        8.8 (Berkeley) 6/16/95
 * $FreeBSD: src/sys/ufs/ffs/ffs_balloc.c,v 1.26.2.1 2002/10/10 19:48:20 dillon Exp $
 */

#include "opt_quota.h"

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/buf.h>
#include <sys/lock.h>
#include <sys/mount.h>
#include <sys/vnode.h>

#include <sys/buf2.h>

#include "quota.h"
#include "inode.h"
#include "ufs_extern.h"

#include "fs.h"
#include "ffs_extern.h"

/*
 * ffs_balloc(struct vnode *a_vp, ufs_daddr_t a_lbn, int a_size,
 *            struct ucred *a_cred, int a_flags, struct buf *a_bpp)
 *
 * Balloc defines the structure of filesystem storage by allocating
 * the physical blocks on a device given the inode and the logical
 * block number in a file.
 *
 * NOTE: B_CLRBUF - this flag tells balloc to clear invalid portions
 *       of the buffer.  However, any dirty bits will override missing
 *       valid bits.  This case occurs when writable mmaps are truncated
 *       and then extended.
 */
int
ffs_balloc(struct vop_balloc_args *ap)
{
        struct inode *ip;
        ufs_daddr_t lbn;
        int size;
        struct ucred *cred;
        int flags;
        struct fs *fs;
        ufs_daddr_t nb;
        struct buf *bp, *nbp, *dbp;
        struct vnode *vp;
        struct indir indirs[UFS_NIADDR + 2];
        ufs_daddr_t newb, *bap, pref;
        int deallocated, osize, nsize, num, i, error;
        ufs_daddr_t *allocib, *blkp, *allocblk, allociblk[UFS_NIADDR + 1];
        ufs_daddr_t *lbns_remfree, lbns[UFS_NIADDR + 1];
        int unwindidx;
        int seqcount;

        vp = ap->a_vp;
        ip = VTOI(vp);
        fs = ip->i_fs;
        lbn = lblkno(fs, ap->a_startoffset);
        size = blkoff(fs, ap->a_startoffset) + ap->a_size;
        if (size > fs->fs_bsize)
                panic("ffs_balloc: blk too big");
        *ap->a_bpp = NULL;
        if (lbn < 0)
                return (EFBIG);
        cred = ap->a_cred;
        flags = ap->a_flags;

        /*
         * The vnode must be locked for us to be able to safely mess
         * around with the inode.
         */
        if (vn_islocked(vp) != LK_EXCLUSIVE) {
                panic("ffs_balloc: vnode %p not exclusively locked!", vp);
        }

        /*
         * If the next write will extend the file into a new block,
         * and the file is currently composed of a fragment
         * this fragment has to be extended to be a full block.
         */
        nb = lblkno(fs, ip->i_size);
        if (nb < UFS_NDADDR && nb < lbn) {
                /*
                 * The filesize prior to this write can fit in direct
                 * blocks (ex. fragmentation is possibly done)
                 * we are now extending the file write beyond
                 * the block which has end of the file prior to this write.
                 */
                osize = blksize(fs, ip, nb);
                /*
                 * osize gives disk allocated size in the last block. It is
                 * either in fragments or a file system block size.
                 */
                if (osize < fs->fs_bsize && osize > 0) {
                        /* A few fragments are already allocated, since the
                         * current extends beyond this block allocated the
                         * complete block as fragments are on in last block.
                         */
                        error = ffs_realloccg(ip, nb,
                                ffs_blkpref(ip, nb, (int)nb, &ip->i_db[0]),
                                osize, (int)fs->fs_bsize, cred, &bp);
                        if (error)
                                return (error);
                        if (DOINGSOFTDEP(vp))
                                softdep_setup_allocdirect(ip, nb,
                                    dofftofsb(fs, bp->b_bio2.bio_offset), 
                                    ip->i_db[nb], fs->fs_bsize, osize, bp);
                        /* adjust the inode size, we just grew */
                        ip->i_size = smalllblktosize(fs, nb + 1);
                        ip->i_db[nb] = dofftofsb(fs, bp->b_bio2.bio_offset);
                        ip->i_flag |= IN_CHANGE | IN_UPDATE;
                        if (flags & B_SYNC)
                                bwrite(bp);
                        else
                                bawrite(bp);
                        /* bp is already released here */
                }
        }
        /*
         * The first UFS_NDADDR blocks are direct blocks
         */
        if (lbn < UFS_NDADDR) {
                nb = ip->i_db[lbn];
                if (nb != 0 && ip->i_size >= smalllblktosize(fs, lbn + 1)) {
                        error = bread(vp, lblktodoff(fs, lbn), fs->fs_bsize, &bp);
                        if (error) {
                                brelse(bp);
                                return (error);
                        }
                        bp->b_bio2.bio_offset = fsbtodoff(fs, nb);
                        *ap->a_bpp = bp;
                        return (0);
                }
                if (nb != 0) {
                        /*
                         * Consider need to reallocate a fragment.
                         */
                        osize = fragroundup(fs, blkoff(fs, ip->i_size));
                        nsize = fragroundup(fs, size);
                        if (nsize <= osize) {
                                error = bread(vp, lblktodoff(fs, lbn), 
                                              osize, &bp);
                                if (error) {
                                        brelse(bp);
                                        return (error);
                                }
                                bp->b_bio2.bio_offset = fsbtodoff(fs, nb);
                        } else {
                                /*
                                 * NOTE: ffs_realloccg() issues a bread().
                                 */
                                error = ffs_realloccg(ip, lbn,
                                    ffs_blkpref(ip, lbn, (int)lbn,
                                        &ip->i_db[0]), osize, nsize, cred, &bp);
                                if (error)
                                        return (error);
                                if (DOINGSOFTDEP(vp))
                                        softdep_setup_allocdirect(ip, lbn,
                                            dofftofsb(fs, bp->b_bio2.bio_offset),
                                            nb, nsize, osize, bp);
                        }
                } else {
                        if (ip->i_size < smalllblktosize(fs, lbn + 1))
                                nsize = fragroundup(fs, size);
                        else
                                nsize = fs->fs_bsize;
                        error = ffs_alloc(ip, lbn,
                            ffs_blkpref(ip, lbn, (int)lbn, &ip->i_db[0]),
                            nsize, cred, &newb);
                        if (error)
                                return (error);
                        bp = getblk(vp, lblktodoff(fs, lbn), nsize, 0, 0);
                        bp->b_bio2.bio_offset = fsbtodoff(fs, newb);
                        if (flags & B_CLRBUF)
                                vfs_bio_clrbuf(bp);
                        if (DOINGSOFTDEP(vp))
                                softdep_setup_allocdirect(ip, lbn, newb, 0,
                                    nsize, 0, bp);
                }
                ip->i_db[lbn] = dofftofsb(fs, bp->b_bio2.bio_offset);
                ip->i_flag |= IN_CHANGE | IN_UPDATE;
                *ap->a_bpp = bp;
                return (0);
        }
        /*
         * Determine the number of levels of indirection.
         */
        pref = 0;
        if ((error = ufs_getlbns(vp, lbn, indirs, &num)) != 0)
                return(error);
#ifdef DIAGNOSTIC
        if (num < 1)
                panic ("ffs_balloc: ufs_bmaparray returned indirect block");
#endif
        /*
         * Get a handle on the data block buffer before working through 
         * indirect blocks to avoid a deadlock between the VM system holding
         * a locked VM page and issuing a BMAP (which tries to lock the
         * indirect blocks), and the filesystem holding a locked indirect
         * block and then trying to read a data block (which tries to lock
         * the underlying VM pages).
         */
        dbp = getblk(vp, lblktodoff(fs, lbn), fs->fs_bsize, 0, 0);

        /*
         * Setup undo history
         */
        allocib = NULL;
        allocblk = allociblk;
        lbns_remfree = lbns;

        unwindidx = -1;

        /*
         * Fetch the first indirect block directly from the inode, allocating
         * one if necessary. 
         */
        --num;
        nb = ip->i_ib[indirs[0].in_off];
        if (nb == 0) {
                pref = ffs_blkpref(ip, lbn, 0, NULL);
                /*
                 * If the filesystem has run out of space we can skip the
                 * full fsync/undo of the main [fail] case since no undo
                 * history has been built yet.  Hence the goto fail2.
                 */
                if ((error = ffs_alloc(ip, lbn, pref, (int)fs->fs_bsize,
                    cred, &newb)) != 0)
                        goto fail2;
                nb = newb;
                *allocblk++ = nb;
                *lbns_remfree++ = indirs[1].in_lbn;
                bp = getblk(vp, lblktodoff(fs, indirs[1].in_lbn),
                            fs->fs_bsize, 0, 0);
                bp->b_bio2.bio_offset = fsbtodoff(fs, nb);
                vfs_bio_clrbuf(bp);
                if (DOINGSOFTDEP(vp)) {
                        softdep_setup_allocdirect(ip,
                            UFS_NDADDR + indirs[0].in_off,
                            newb, 0, fs->fs_bsize, 0, bp);
                        bdwrite(bp);
                } else {
                        /*
                         * Write synchronously so that indirect blocks
                         * never point at garbage.
                         */
                        if (DOINGASYNC(vp))
                                bdwrite(bp);
                        else if ((error = bwrite(bp)) != 0)
                                goto fail;
                }
                allocib = &ip->i_ib[indirs[0].in_off];
                *allocib = nb;
                ip->i_flag |= IN_CHANGE | IN_UPDATE;
        }

        /*
         * Fetch through the indirect blocks, allocating as necessary.
         */
        for (i = 1;;) {
                error = bread(vp, lblktodoff(fs, indirs[i].in_lbn), (int)fs->fs_bsize, &bp);
                if (error) {
                        brelse(bp);
                        goto fail;
                }
                bap = (ufs_daddr_t *)bp->b_data;
                nb = bap[indirs[i].in_off];
                if (i == num)
                        break;
                i += 1;
                if (nb != 0) {
                        bqrelse(bp);
                        continue;
                }
                if (pref == 0)
                        pref = ffs_blkpref(ip, lbn, 0, NULL);
                if ((error =
                    ffs_alloc(ip, lbn, pref, (int)fs->fs_bsize, cred, &newb)) != 0) {
                        brelse(bp);
                        goto fail;
                }
                nb = newb;
                *allocblk++ = nb;
                *lbns_remfree++ = indirs[i].in_lbn;
                nbp = getblk(vp, lblktodoff(fs, indirs[i].in_lbn),
                             fs->fs_bsize, 0, 0);
                nbp->b_bio2.bio_offset = fsbtodoff(fs, nb);
                vfs_bio_clrbuf(nbp);
                if (DOINGSOFTDEP(vp)) {
                        softdep_setup_allocindir_meta(nbp, ip, bp,
                            indirs[i - 1].in_off, nb);
                        bdwrite(nbp);
                } else {
                        /*
                         * Write synchronously so that indirect blocks
                         * never point at garbage.
                         */
                        if ((error = bwrite(nbp)) != 0) {
                                brelse(bp);
                                goto fail;
                        }
                }
                bap[indirs[i - 1].in_off] = nb;
                if (allocib == NULL && unwindidx < 0)
                        unwindidx = i - 1;
                /*
                 * If required, write synchronously, otherwise use
                 * delayed write.
                 */
                if (flags & B_SYNC) {
                        bwrite(bp);
                } else {
                        if (bp->b_bufsize == fs->fs_bsize)
                                bp->b_flags |= B_CLUSTEROK;
                        bdwrite(bp);
                }
        }

        /*
         * Get the data block, allocating if necessary.  We have already
         * called getblk() on the data block buffer, dbp.  If we have to
         * allocate it and B_CLRBUF has been set the inference is an intention
         * to zero out the related disk blocks, so we do not have to issue
         * a read.  Instead we simply call vfs_bio_clrbuf().  If B_CLRBUF is
         * not set the caller intends to overwrite the entire contents of the
         * buffer and we don't waste time trying to clean up the contents.
         *
         * bp references the current indirect block.  When allocating, 
         * the block must be updated.
         */
        if (nb == 0) {
                pref = ffs_blkpref(ip, lbn, indirs[i].in_off, &bap[0]);
                error = ffs_alloc(ip,
                    lbn, pref, (int)fs->fs_bsize, cred, &newb);
                if (error) {
                        brelse(bp);
                        goto fail;
                }
                nb = newb;
                *allocblk++ = nb;
                *lbns_remfree++ = lbn;
                dbp->b_bio2.bio_offset = fsbtodoff(fs, nb);
                if (flags & B_CLRBUF)
                        vfs_bio_clrbuf(dbp);
                if (DOINGSOFTDEP(vp))
                        softdep_setup_allocindir_page(ip, lbn, bp,
                            indirs[i].in_off, nb, 0, dbp);
                bap[indirs[i].in_off] = nb;
                /*
                 * If required, write synchronously, otherwise use
                 * delayed write.
                 */
                if (flags & B_SYNC) {
                        bwrite(bp);
                } else {
                        if (bp->b_bufsize == fs->fs_bsize)
                                bp->b_flags |= B_CLUSTEROK;
                        bdwrite(bp);
                }
                *ap->a_bpp = dbp;
                return (0);
        }
        brelse(bp);

        /*
         * At this point all related indirect blocks have been allocated
         * if necessary and released.  bp is no longer valid.  dbp holds
         * our getblk()'d data block.
         *
         * XXX we previously performed a cluster_read operation here.
         */
        if (flags & B_CLRBUF) {
                /*
                 * If B_CLRBUF is set we must validate the invalid portions
                 * of the buffer.  This typically requires a read-before-
                 * write.  The strategy call will fill in bio_offset in that
                 * case.
                 *
                 * If we hit this case we do a cluster read if possible
                 * since nearby data blocks are likely to be accessed soon
                 * too.
                 */
                if ((dbp->b_flags & B_CACHE) == 0) {
                        bqrelse(dbp);
                        seqcount = (flags & B_SEQMASK) >> B_SEQSHIFT;
                        if (seqcount &&
                            (vp->v_mount->mnt_flag & MNT_NOCLUSTERR) == 0) {
                                error = cluster_read(vp, (off_t)ip->i_size,
                                            lblktodoff(fs, lbn),
                                            (int)fs->fs_bsize, 
                                            fs->fs_bsize,
                                            seqcount * MAXBSIZE,
                                            &dbp);
                        } else {
                                error = bread(vp, lblktodoff(fs, lbn),
                                              (int)fs->fs_bsize, &dbp);
                        }
                        if (error)
                                goto fail;
                } else {
                        dbp->b_bio2.bio_offset = fsbtodoff(fs, nb);
                }
        } else {
                /*
                 * If B_CLRBUF is not set the caller intends to overwrite
                 * the entire contents of the buffer.  We can simply set
                 * bio_offset and we are done.
                 */
                dbp->b_bio2.bio_offset = fsbtodoff(fs, nb);
        }
        *ap->a_bpp = dbp;
        return (0);
fail:
        /*
         * If we have failed part way through block allocation, we
         * have to deallocate any indirect blocks that we have allocated.
         * We have to fsync the file before we start to get rid of all
         * of its dependencies so that we do not leave them dangling.
         * We have to sync it at the end so that the soft updates code
         * does not find any untracked changes. Although this is really
         * slow, running out of disk space is not expected to be a common
         * occurence. The error return from fsync is ignored as we already
         * have an error to return to the user.
         */
        VOP_FSYNC(vp, MNT_WAIT, 0);
        for (deallocated = 0, blkp = allociblk, lbns_remfree = lbns;
             blkp < allocblk; blkp++, lbns_remfree++) {
                /*
                 * We shall not leave the freed blocks on the vnode
                 * buffer object lists.
                 */
                bp = getblk(vp, lblktodoff(fs, *lbns_remfree), fs->fs_bsize, 0, 0);
                bp->b_flags |= (B_INVAL | B_RELBUF);
                brelse(bp);
                deallocated += fs->fs_bsize;
        }

        if (allocib != NULL) {
                *allocib = 0;
        } else if (unwindidx >= 0) {
                int r;

                r = bread(vp, lblktodoff(fs, indirs[unwindidx].in_lbn), (int)fs->fs_bsize, &bp);
                if (r) {
                        panic("Could not unwind indirect block, error %d", r);
                        brelse(bp);
                } else {
                        bap = (ufs_daddr_t *)bp->b_data;
                        bap[indirs[unwindidx].in_off] = 0;
                        if (flags & B_SYNC) {
                                bwrite(bp);
                        } else {
                                if (bp->b_bufsize == fs->fs_bsize)
                                        bp->b_flags |= B_CLUSTEROK;
                                bdwrite(bp);
                        }
                }
        }
        if (deallocated) {
#ifdef QUOTA
                /*
                 * Restore user's disk quota because allocation failed.
                 */
                (void) ufs_chkdq(ip, (long)-btodb(deallocated), cred, FORCE);
#endif
                ip->i_blocks -= btodb(deallocated);
                ip->i_flag |= IN_CHANGE | IN_UPDATE;
        }
        VOP_FSYNC(vp, MNT_WAIT, 0);

        /*
         * After the buffers are invalidated and on-disk pointers are
         * cleared, free the blocks.
         */
        for (blkp = allociblk; blkp < allocblk; blkp++) {
                ffs_blkfree(ip, *blkp, fs->fs_bsize);
        }

        /*
         * Cleanup the data block we getblk()'d before returning.
         */
fail2:
        brelse(dbp);
        return (error);
}