/*
 * 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_ioctl32.h"
#include "xfs_vnodeops.h"

#include <linux/dcache.h>
#include <linux/smp_lock.h>

static struct vm_operations_struct xfs_file_vm_ops;
#ifdef CONFIG_XFS_DMAPI
static struct vm_operations_struct xfs_dmapi_file_vm_ops;
#endif

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

        BUG_ON(iocb->ki_pos != pos);
        if (unlikely(file->f_flags & O_DIRECT))
                ioflags |= IO_ISDIRECT;
        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_read(
        struct kiocb            *iocb,
        const struct iovec      *iov,
        unsigned long           nr_segs,
        loff_t                  pos)
{
        return __xfs_file_read(iocb, iov, nr_segs, IO_ISAIO, pos);
}

STATIC ssize_t
xfs_file_aio_read_invis(
        struct kiocb            *iocb,
        const struct iovec      *iov,
        unsigned long           nr_segs,
        loff_t                  pos)
{
        return __xfs_file_read(iocb, iov, nr_segs, IO_ISAIO|IO_INVIS, pos);
}

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

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

STATIC ssize_t
xfs_file_aio_write_invis(
        struct kiocb            *iocb,
        const struct iovec      *iov,
        unsigned long           nr_segs,
        loff_t                  pos)
{
        return __xfs_file_write(iocb, iov, nr_segs, IO_ISAIO|IO_INVIS, pos);
}

STATIC ssize_t
xfs_file_splice_read(
        struct file             *infilp,
        loff_t                  *ppos,
        struct pipe_inode_info  *pipe,
        size_t                  len,
        unsigned int            flags)
{
        return xfs_splice_read(XFS_I(infilp->f_path.dentry->d_inode),
                                   infilp, ppos, pipe, len, flags, 0);
}

STATIC ssize_t
xfs_file_splice_read_invis(
        struct file             *infilp,
        loff_t                  *ppos,
        struct pipe_inode_info  *pipe,
        size_t                  len,
        unsigned int            flags)
{
        return xfs_splice_read(XFS_I(infilp->f_path.dentry->d_inode),
                                   infilp, ppos, pipe, len, flags, IO_INVIS);
}

STATIC ssize_t
xfs_file_splice_write(
        struct pipe_inode_info  *pipe,
        struct file             *outfilp,
        loff_t                  *ppos,
        size_t                  len,
        unsigned int            flags)
{
        return xfs_splice_write(XFS_I(outfilp->f_path.dentry->d_inode),
                                    pipe, outfilp, ppos, len, flags, 0);
}

STATIC ssize_t
xfs_file_splice_write_invis(
        struct pipe_inode_info  *pipe,
        struct file             *outfilp,
        loff_t                  *ppos,
        size_t                  len,
        unsigned int            flags)
{
        return xfs_splice_write(XFS_I(outfilp->f_path.dentry->d_inode),
                                    pipe, outfilp, ppos, len, flags, IO_INVIS);
}

STATIC int
xfs_file_open(
        struct inode    *inode,
        struct file     *filp)
{
        if (!(filp->f_flags & O_LARGEFILE) && i_size_read(inode) > MAX_NON_LFS)
                return -EFBIG;
        return -xfs_open(XFS_I(inode));
}

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

STATIC int
xfs_file_fsync(
        struct file     *filp,
        struct dentry   *dentry,
        int             datasync)
{
        int             flags = FSYNC_WAIT;

        if (datasync)
                flags |= FSYNC_DATA;
        xfs_iflags_clear(XFS_I(dentry->d_inode), XFS_ITRUNCATED);
        return -xfs_fsync(XFS_I(dentry->d_inode), flags,
                        (xfs_off_t)0, (xfs_off_t)-1);
}

#ifdef CONFIG_XFS_DMAPI
STATIC int
xfs_vm_fault(
        struct vm_area_struct   *vma,
        struct vm_fault *vmf)
{
        struct inode    *inode = vma->vm_file->f_path.dentry->d_inode;
        bhv_vnode_t     *vp = vn_from_inode(inode);

        ASSERT_ALWAYS(vp->v_vfsp->vfs_flag & VFS_DMI);
        if (XFS_SEND_MMAP(XFS_VFSTOM(vp->v_vfsp), vma, 0))
                return VM_FAULT_SIGBUS;
        return filemap_fault(vma, vmf);
}
#endif /* CONFIG_XFS_DMAPI */

/*
 * Unfortunately we can't just use the clean and simple readdir implementation
 * below, because nfs might call back into ->lookup from the filldir callback
 * and that will deadlock the low-level btree code.
 *
 * Hopefully we'll find a better workaround that allows to use the optimal
 * version at least for local readdirs for 2.6.25.
 */
#if 0
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, inode->i_size);

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

struct hack_dirent {
        u64             ino;
        loff_t          offset;
        int             namlen;
        unsigned int    d_type;
        char            name[];
};

struct hack_callback {
        char            *dirent;
        size_t          len;
        size_t          used;
};

STATIC int
xfs_hack_filldir(
        void            *__buf,
        const char      *name,
        int             namlen,
        loff_t          offset,
        u64             ino,
        unsigned int    d_type)
{
        struct hack_callback *buf = __buf;
        struct hack_dirent *de = (struct hack_dirent *)(buf->dirent + buf->used);
        unsigned int reclen;

        reclen = ALIGN(sizeof(struct hack_dirent) + namlen, sizeof(u64));
        if (buf->used + reclen > buf->len)
                return -EINVAL;

        de->namlen = namlen;
        de->offset = offset;
        de->ino = ino;
        de->d_type = d_type;
        memcpy(de->name, name, namlen);
        buf->used += reclen;
        return 0;
}

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);
        struct hack_callback buf;
        struct hack_dirent *de;
        int             error;
        loff_t          size;
        int             eof = 0;
        xfs_off_t       start_offset, curr_offset, offset;

        /*
         * Try fairly hard to get memory
         */
        buf.len = PAGE_CACHE_SIZE;
        do {
                buf.dirent = kmalloc(buf.len, GFP_KERNEL);
                if (buf.dirent)
                        break;
                buf.len >>= 1;
        } while (buf.len >= 1024);

        if (!buf.dirent)
                return -ENOMEM;

        curr_offset = filp->f_pos;
        if (curr_offset == 0x7fffffff)
                offset = 0xffffffff;
        else
                offset = filp->f_pos;

        while (!eof) {
                unsigned int reclen;

                start_offset = offset;

                buf.used = 0;
                error = -xfs_readdir(ip, &buf, buf.len, &offset,
                                     xfs_hack_filldir);
                if (error || offset == start_offset) {
                        size = 0;
                        break;
                }

                size = buf.used;
                de = (struct hack_dirent *)buf.dirent;
                curr_offset = de->offset /* & 0x7fffffff */;
                while (size > 0) {
                        if (filldir(dirent, de->name, de->namlen,
                                        curr_offset & 0x7fffffff,
                                        de->ino, de->d_type)) {
                                goto done;
                        }

                        reclen = ALIGN(sizeof(struct hack_dirent) + de->namlen,
                                       sizeof(u64));
                        size -= reclen;
                        de = (struct hack_dirent *)((char *)de + reclen);
                        curr_offset = de->offset /* & 0x7fffffff */;
                }
        }

 done:
        if (!error) {
                if (size == 0)
                        filp->f_pos = offset & 0x7fffffff;
                else if (de)
                        filp->f_pos = curr_offset;
        }

        kfree(buf.dirent);
        return error;
}
#endif

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;

#ifdef CONFIG_XFS_DMAPI
        if (XFS_M(filp->f_path.dentry->d_inode->i_sb)->m_flags & XFS_MOUNT_DMAPI)
                vma->vm_ops = &xfs_dmapi_file_vm_ops;
#endif /* CONFIG_XFS_DMAPI */

        file_accessed(filp);
        return 0;
}

STATIC long
xfs_file_ioctl(
        struct file     *filp,
        unsigned int    cmd,
        unsigned long   p)
{
        int             error;
        struct inode    *inode = filp->f_path.dentry->d_inode;

        error = xfs_ioctl(XFS_I(inode), filp, 0, cmd, (void __user *)p);
        xfs_iflags_set(XFS_I(inode), XFS_IMODIFIED);

        /* NOTE:  some of the ioctl's return positive #'s as a
         *        byte count indicating success, such as
         *        readlink_by_handle.  So we don't "sign flip"
         *        like most other routines.  This means true
         *        errors need to be returned as a negative value.
         */
        return error;
}

STATIC long
xfs_file_ioctl_invis(
        struct file     *filp,
        unsigned int    cmd,
        unsigned long   p)
{
        int             error;
        struct inode    *inode = filp->f_path.dentry->d_inode;

        error = xfs_ioctl(XFS_I(inode), filp, IO_INVIS, cmd, (void __user *)p);
        xfs_iflags_set(XFS_I(inode), XFS_IMODIFIED);

        /* NOTE:  some of the ioctl's return positive #'s as a
         *        byte count indicating success, such as
         *        readlink_by_handle.  So we don't "sign flip"
         *        like most other routines.  This means true
         *        errors need to be returned as a negative value.
         */
        return error;
}

#ifdef CONFIG_XFS_DMAPI
#ifdef HAVE_VMOP_MPROTECT
STATIC int
xfs_vm_mprotect(
        struct vm_area_struct *vma,
        unsigned int    newflags)
{
        struct inode    *inode = vma->vm_file->f_path.dentry->d_inode;
        struct xfs_mount *mp = XFS_M(inode->i_sb);
        int             error = 0;

        if (mp->m_flags & XFS_MOUNT_DMAPI) {
                if ((vma->vm_flags & VM_MAYSHARE) &&
                    (newflags & VM_WRITE) && !(vma->vm_flags & VM_WRITE))
                        error = XFS_SEND_MMAP(mp, vma, VM_WRITE);
        }
        return error;
}
#endif /* HAVE_VMOP_MPROTECT */
#endif /* CONFIG_XFS_DMAPI */

#ifdef HAVE_FOP_OPEN_EXEC
/* If the user is attempting to execute a file that is offline then
 * we have to trigger a DMAPI READ event before the file is marked as busy
 * otherwise the invisible I/O will not be able to write to the file to bring
 * it back online.
 */
STATIC int
xfs_file_open_exec(
        struct inode    *inode)
{
        struct xfs_mount *mp = XFS_M(inode->i_sb);

        if (unlikely(mp->m_flags & XFS_MOUNT_DMAPI)) {
                if (DM_EVENT_ENABLED(XFS_I(inode), DM_EVENT_READ)) {
                        bhv_vnode_t *vp = vn_from_inode(inode);

                        return -XFS_SEND_DATA(mp, DM_EVENT_READ,
                                                vp, 0, 0, 0, NULL);
                }
        }

        return 0;
}
#endif /* HAVE_FOP_OPEN_EXEC */

/*
 * 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 page             *page)
{
        return block_page_mkwrite(vma, page, 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_invis_file_operations = {
        .llseek         = generic_file_llseek,
        .read           = do_sync_read,
        .write          = do_sync_write,
        .aio_read       = xfs_file_aio_read_invis,
        .aio_write      = xfs_file_aio_write_invis,
        .splice_read    = xfs_file_splice_read_invis,
        .splice_write   = xfs_file_splice_write_invis,
        .unlocked_ioctl = xfs_file_ioctl_invis,
#ifdef CONFIG_COMPAT
        .compat_ioctl   = xfs_file_compat_invis_ioctl,
#endif
        .mmap           = xfs_file_mmap,
        .open           = xfs_file_open,
        .release        = xfs_file_release,
        .fsync          = xfs_file_fsync,
};


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

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

#ifdef CONFIG_XFS_DMAPI
static struct vm_operations_struct xfs_dmapi_file_vm_ops = {
        .fault          = xfs_vm_fault,
        .page_mkwrite   = xfs_vm_page_mkwrite,
#ifdef HAVE_VMOP_MPROTECT
        .mprotect       = xfs_vm_mprotect,
#endif
};
#endif /* CONFIG_XFS_DMAPI */