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/*

 *  linux/fs/ext2/file.c

 *

 * Copyright (C) 1992, 1993, 1994, 1995

 * Remy Card (card@masi.ibp.fr)

 * Laboratoire MASI - Institut Blaise Pascal

 * Universite Pierre et Marie Curie (Paris VI)

 *

 *  from

 *

 *  linux/fs/minix/file.c

 *

 *  Copyright (C) 1991, 1992  Linus Torvalds

 *

 *  ext2 fs regular file handling primitives

 */

#include <asm/segment.h>

#include <asm/system.h>

#include <linux/errno.h>

#include <linux/fs.h>

#include <linux/ext2_fs.h>

#include <linux/fcntl.h>

#include <linux/sched.h>

#include <linux/stat.h>

#include <linux/locks.h>

#include <linux/mm.h>

#include <linux/pagemap.h>

#define NBUF    32

#define MIN(a,b) (((a)<(b))?(a):(b))

#define MAX(a,b) (((a)>(b))?(a):(b))

static int ext2_file_write (struct inode *, struct file *, const char *, int);

static void ext2_release_file (struct inode *, struct file *);

/*

 * We have mostly NULL's here: the current defaults are ok for

 * the ext2 filesystem.

 */

static struct file_operations ext2_file_operations = {

        NULL,                   /* lseek - default */

        generic_file_read,      /* read */

        ext2_file_write,        /* write */

        NULL,                   /* readdir - bad */

        NULL,                   /* select - default */

        ext2_ioctl,             /* ioctl */

        generic_file_mmap,      /* mmap */

        NULL,                   /* no special open is needed */

        ext2_release_file,      /* release */

        ext2_sync_file,         /* fsync */

        NULL,                   /* fasync */

        NULL,                   /* check_media_change */

        NULL                    /* revalidate */

};

struct inode_operations ext2_file_inode_operations = {

        &ext2_file_operations,/* default file operations */

        NULL,                   /* create */

        NULL,                   /* lookup */

        NULL,                   /* link */

        NULL,                   /* unlink */

        NULL,                   /* symlink */

        NULL,                   /* mkdir */

        NULL,                   /* rmdir */

        NULL,                   /* mknod */

        NULL,                   /* rename */

        NULL,                   /* readlink */

        NULL,                   /* follow_link */

        generic_readpage,       /* readpage */

        NULL,                   /* writepage */

        ext2_bmap,              /* bmap */

        ext2_truncate,          /* truncate */

        ext2_permission,        /* permission */

        NULL                    /* smap */

};

static int ext2_file_write (struct inode * inode, struct file * filp,

                            const char * buf, int count)

{

        const loff_t two_gb = 2147483647;

        loff_t pos;

        off_t pos2;

        long block;

        int offset;

        int written, c;

        struct buffer_head * bh, *bufferlist[NBUF];

        struct super_block * sb;

        int err;

        int i,buffercount,write_error;

        write_error = buffercount = 0;

        if (!inode) {

                printk("ext2_file_write: inode = NULL\n");

                return -EINVAL;

        }

        sb = inode->i_sb;

        if (sb->s_flags & MS_RDONLY)

                /*

                 * This fs has been automatically remounted ro because of errors

                 */

                return -ENOSPC;

        if (!S_ISREG(inode->i_mode)) {

                ext2_warning (sb, "ext2_file_write", "mode = %07o",

                              inode->i_mode);

                return -EINVAL;

        }

        if (filp->f_flags & O_APPEND)

                pos = inode->i_size;

        else

                pos = filp->f_pos;

        pos2 = (off_t) pos;

        /*

         * If a file has been opened in synchronous mode, we have to ensure

         * that meta-data will also be written synchronously.  Thus, we

         * set the i_osync field.  This field is tested by the allocation

         * routines.

         */

        if (filp->f_flags & O_SYNC)

                inode->u.ext2_i.i_osync++;

        block = pos2 >> EXT2_BLOCK_SIZE_BITS(sb);

        offset = pos2 & (sb->s_blocksize - 1);

        c = sb->s_blocksize - offset;

        written = 0;

        while (count > 0) {

                if (pos > two_gb) {

                        if (!written)

                                written = -EFBIG;

                        break;

                }

                bh = ext2_getblk (inode, block, 1, &err);

                if (!bh) {

                        if (!written)

                                written = err;

                        break;

                }

                count -= c;

                if (count < 0)

                        c += count;

                if (c != sb->s_blocksize && !buffer_uptodate(bh)) {

                        ll_rw_block (READ, 1, &bh);

                        wait_on_buffer (bh);

                        if (!buffer_uptodate(bh)) {

                                brelse (bh);

                                if (!written)

                                        written = -EIO;

                                break;

                        }

                }

                memcpy_fromfs (bh->b_data + offset, buf, c);

                update_vm_cache(inode, pos, bh->b_data + offset, c);

                pos2 += c;

                pos += c;

                written += c;

                buf += c;

                mark_buffer_uptodate(bh, 1);

                mark_buffer_dirty(bh, 0);

                if (filp->f_flags & O_SYNC)

                        bufferlist[buffercount++] = bh;

                else

                        brelse(bh);

                if (buffercount == NBUF){

                        ll_rw_block(WRITE, buffercount, bufferlist);

                        for(i=0; i<buffercount; i++){

                                wait_on_buffer(bufferlist[i]);

                                if (!buffer_uptodate(bufferlist[i]))

                                        write_error=1;

                                brelse(bufferlist[i]);

                        }

                        buffercount=0;

                }

                if(write_error)

                        break;

                block++;

                offset = 0;

                c = sb->s_blocksize;

        }

        if ( buffercount ){

                ll_rw_block(WRITE, buffercount, bufferlist);

                for(i=0; i<buffercount; i++){

                        wait_on_buffer(bufferlist[i]);

                        if (!buffer_uptodate(bufferlist[i]))

                                write_error=1;

                        brelse(bufferlist[i]);

                }

        }

        if (pos > inode->i_size)

                inode->i_size = pos;

        if (filp->f_flags & O_SYNC)

                inode->u.ext2_i.i_osync--;

        inode->i_ctime = inode->i_mtime = CURRENT_TIME;

        filp->f_pos = pos;

        inode->i_dirt = 1;

        return written;

}

/*

 * Called when a inode is released. Note that this is different

 * from ext2_open: open gets called at every open, but release

 * gets called only when /all/ the files are closed.

 */

static void ext2_release_file (struct inode * inode, struct file * filp)

{

        if (filp->f_mode & 2)

                ext2_discard_prealloc (inode);

}