/*
 * Copyright (c) 2000-2005 Silicon Graphics, Inc.
 * All Rights Reserved.
 *
 * 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.
 *
 * This program is distributed in the hope that it would 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, write the Free Software Foundation,
 * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */
#include "xfs.h"
#include "xfs_bit.h"
#include "xfs_log.h"
#include "xfs_inum.h"
#include "xfs_sb.h"
#include "xfs_ag.h"
#include "xfs_dir2.h"
#include "xfs_trans.h"
#include "xfs_dmapi.h"
#include "xfs_mount.h"
#include "xfs_bmap_btree.h"
#include "xfs_alloc_btree.h"
#include "xfs_ialloc_btree.h"
#include "xfs_alloc.h"
#include "xfs_btree.h"
#include "xfs_attr_sf.h"
#include "xfs_dir2_sf.h"
#include "xfs_dinode.h"
#include "xfs_inode.h"
#include "xfs_error.h"
#include "xfs_rw.h"
#include "xfs_vnodeops.h"
#include "xfs_da_btree.h"
#include "xfs_ioctl.h"

#include <linux/dcache.h>

static const struct vm_operations_struct xfs_file_vm_ops;

STATIC ssize_t
xfs_file_aio_read(
        struct kiocb            *iocb,
        const struct iovec      *iov,
        unsigned long           nr_segs,
        loff_t                  pos)
{
        struct file             *file = iocb->ki_filp;
        int                     ioflags = IO_ISAIO;

        BUG_ON(iocb->ki_pos != pos);
        if (unlikely(file->f_flags & O_DIRECT))
                ioflags |= IO_ISDIRECT;
        if (file->f_mode & FMODE_NOCMTIME)
                ioflags |= IO_INVIS;
        return xfs_read(XFS_I(file->f_path.dentry->d_inode), iocb, iov,
                                nr_segs, &iocb->ki_pos, ioflags);
}

STATIC ssize_t
xfs_file_aio_write(
        struct kiocb            *iocb,
        const struct iovec      *iov,
        unsigned long           nr_segs,
        loff_t                  pos)
{
        struct file             *file = iocb->ki_filp;
        int                     ioflags = IO_ISAIO;

        BUG_ON(iocb->ki_pos != pos);
        if (unlikely(file->f_flags & O_DIRECT))
                ioflags |= IO_ISDIRECT;
        if (file->f_mode & FMODE_NOCMTIME)
                ioflags |= IO_INVIS;
        return xfs_write(XFS_I(file->f_mapping->host), iocb, iov, nr_segs,
                                &iocb->ki_pos, ioflags);
}

STATIC ssize_t
xfs_file_splice_read(
        struct file             *infilp,
        loff_t                  *ppos,
        struct pipe_inode_info  *pipe,
        size_t                  len,
        unsigned int            flags)
{
        int                     ioflags = 0;

        if (infilp->f_mode & FMODE_NOCMTIME)
                ioflags |= IO_INVIS;

        return xfs_splice_read(XFS_I(infilp->f_path.dentry->d_inode),
                                   infilp, ppos, pipe, len, flags, ioflags);
}

STATIC ssize_t
xfs_file_splice_write(
        struct pipe_inode_info  *pipe,
        struct file             *outfilp,
        loff_t                  *ppos,
        size_t                  len,
        unsigned int            flags)
{
        int                     ioflags = 0;

        if (outfilp->f_mode & FMODE_NOCMTIME)
                ioflags |= IO_INVIS;

        return xfs_splice_write(XFS_I(outfilp->f_path.dentry->d_inode),
                                    pipe, outfilp, ppos, len, flags, ioflags);
}

STATIC int
xfs_file_open(
        struct inode    *inode,
        struct file     *file)
{
        if (!(file->f_flags & O_LARGEFILE) && i_size_read(inode) > MAX_NON_LFS)
                return -EFBIG;
        if (XFS_FORCED_SHUTDOWN(XFS_M(inode->i_sb)))
                return -EIO;
        return 0;
}

STATIC int
xfs_dir_open(
        struct inode    *inode,
        struct file     *file)
{
        struct xfs_inode *ip = XFS_I(inode);
        int             mode;
        int             error;

        error = xfs_file_open(inode, file);
        if (error)
                return error;

        /*
         * If there are any blocks, read-ahead block 0 as we're almost
         * certain to have the next operation be a read there.
         */
        mode = xfs_ilock_map_shared(ip);
        if (ip->i_d.di_nextents > 0)
                xfs_da_reada_buf(NULL, ip, 0, XFS_DATA_FORK);
        xfs_iunlock(ip, mode);
        return 0;
}

STATIC int
xfs_file_release(
        struct inode    *inode,
        struct file     *filp)
{
        return -xfs_release(XFS_I(inode));
}

/*
 * We ignore the datasync flag here because a datasync is effectively
 * identical to an fsync. That is, datasync implies that we need to write
 * only the metadata needed to be able to access the data that is written
 * if we crash after the call completes. Hence if we are writing beyond
 * EOF we have to log the inode size change as well, which makes it a
 * full fsync. If we don't write beyond EOF, the inode core will be
 * clean in memory and so we don't need to log the inode, just like
 * fsync.
 */
STATIC int
xfs_file_fsync(
        struct file             *file,
        struct dentry           *dentry,
        int                     datasync)
{
        struct xfs_inode        *ip = XFS_I(dentry->d_inode);

        xfs_iflags_clear(ip, XFS_ITRUNCATED);
        return -xfs_fsync(ip);
}

STATIC int
xfs_file_readdir(
        struct file     *filp,
        void            *dirent,
        filldir_t       filldir)
{
        struct inode    *inode = filp->f_path.dentry->d_inode;
        xfs_inode_t     *ip = XFS_I(inode);
        int             error;
        size_t          bufsize;

        /*
         * The Linux API doesn't pass down the total size of the buffer
         * we read into down to the filesystem.  With the filldir concept
         * it's not needed for correct information, but the XFS dir2 leaf
         * code wants an estimate of the buffer size to calculate it's
         * readahead window and size the buffers used for mapping to
         * physical blocks.
         *
         * Try to give it an estimate that's good enough, maybe at some
         * point we can change the ->readdir prototype to include the
         * buffer size.
         */
        bufsize = (size_t)min_t(loff_t, PAGE_SIZE, ip->i_d.di_size);

        error = xfs_readdir(ip, dirent, bufsize,
                                (xfs_off_t *)&filp->f_pos, filldir);
        if (error)
                return -error;
        return 0;
}

STATIC int
xfs_file_mmap(
        struct file     *filp,
        struct vm_area_struct *vma)
{
        vma->vm_ops = &xfs_file_vm_ops;
        vma->vm_flags |= VM_CAN_NONLINEAR;

        file_accessed(filp);
        return 0;
}

/*
 * mmap()d file has taken write protection fault and is being made
 * writable. We can set the page state up correctly for a writable
 * page, which means we can do correct delalloc accounting (ENOSPC
 * checking!) and unwritten extent mapping.
 */
STATIC int
xfs_vm_page_mkwrite(
        struct vm_area_struct   *vma,
        struct vm_fault         *vmf)
{
        return block_page_mkwrite(vma, vmf, xfs_get_blocks);
}

const struct file_operations xfs_file_operations = {
        .llseek         = generic_file_llseek,
        .read           = do_sync_read,
        .write          = do_sync_write,
        .aio_read       = xfs_file_aio_read,
        .aio_write      = xfs_file_aio_write,
        .splice_read    = xfs_file_splice_read,
        .splice_write   = xfs_file_splice_write,
        .unlocked_ioctl = xfs_file_ioctl,
#ifdef CONFIG_COMPAT
        .compat_ioctl   = xfs_file_compat_ioctl,
#endif
        .mmap           = xfs_file_mmap,
        .open           = xfs_file_open,
        .release        = xfs_file_release,
        .fsync          = xfs_file_fsync,
#ifdef HAVE_FOP_OPEN_EXEC
        .open_exec      = xfs_file_open_exec,
#endif
};

const struct file_operations xfs_dir_file_operations = {
        .open           = xfs_dir_open,
        .read           = generic_read_dir,
        .readdir        = xfs_file_readdir,
        .llseek         = generic_file_llseek,
        .unlocked_ioctl = xfs_file_ioctl,
#ifdef CONFIG_COMPAT
        .compat_ioctl   = xfs_file_compat_ioctl,
#endif
        .fsync          = xfs_file_fsync,
};

static const struct vm_operations_struct xfs_file_vm_ops = {
        .fault          = filemap_fault,
        .page_mkwrite   = xfs_vm_page_mkwrite,
};