f42faf4fa4
Add the new external read function. Its temporarily in jdata.c even though the protoype is in ops_file.h - this will change shortly. The current implementation will change to a page cache one when that happens. In order to effect the above changes, the various internal inodes now have Linux inodes attached to them. We keep the references to the Linux inodes, rather than the gfs2_inodes in the super block. In order to get everything to work correctly I've had to reorder the init sequence on mount (which I should probably have done earlier when .gfs2_admin was made visible). Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
390 lines
8.5 KiB
C
390 lines
8.5 KiB
C
/*
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* Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
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* Copyright (C) 2004-2005 Red Hat, Inc. All rights reserved.
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*
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* This copyrighted material is made available to anyone wishing to use,
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* modify, copy, or redistribute it subject to the terms and conditions
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* of the GNU General Public License v.2.
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*/
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#include <linux/sched.h>
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#include <linux/slab.h>
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#include <linux/spinlock.h>
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#include <linux/completion.h>
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#include <linux/buffer_head.h>
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#include <asm/semaphore.h>
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#include <asm/uaccess.h>
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#include "gfs2.h"
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#include "bmap.h"
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#include "inode.h"
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#include "jdata.h"
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#include "meta_io.h"
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#include "trans.h"
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int gfs2_internal_read(struct gfs2_inode *ip,
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struct file_ra_state *ra_state,
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char *buf, loff_t *pos, unsigned size)
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{
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return gfs2_jdata_read_mem(ip, buf, *pos, size);
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}
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int gfs2_jdata_get_buffer(struct gfs2_inode *ip, uint64_t block, int new,
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struct buffer_head **bhp)
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{
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struct buffer_head *bh;
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int error = 0;
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if (new) {
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bh = gfs2_meta_new(ip->i_gl, block);
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gfs2_trans_add_bh(ip->i_gl, bh, 1);
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gfs2_metatype_set(bh, GFS2_METATYPE_JD, GFS2_FORMAT_JD);
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gfs2_buffer_clear_tail(bh, sizeof(struct gfs2_meta_header));
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} else {
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error = gfs2_meta_read(ip->i_gl, block,
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DIO_START | DIO_WAIT, &bh);
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if (error)
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return error;
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if (gfs2_metatype_check(ip->i_sbd, bh, GFS2_METATYPE_JD)) {
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brelse(bh);
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return -EIO;
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}
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}
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*bhp = bh;
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return 0;
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}
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/**
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* gfs2_copy2mem - Trivial copy function for gfs2_jdata_read()
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* @bh: The buffer to copy from, or NULL meaning zero the buffer
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* @buf: The buffer to copy/zero
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* @offset: The offset in the buffer to copy from
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* @size: The amount of data to copy/zero
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*
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* Returns: errno
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*/
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int gfs2_copy2mem(struct buffer_head *bh, char **buf, unsigned int offset,
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unsigned int size)
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{
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if (bh)
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memcpy(*buf, bh->b_data + offset, size);
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else
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memset(*buf, 0, size);
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*buf += size;
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return 0;
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}
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/**
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* gfs2_copy2user - Copy bytes to user space for gfs2_jdata_read()
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* @bh: The buffer
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* @buf: The destination of the data
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* @offset: The offset into the buffer
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* @size: The amount of data to copy
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*
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* Returns: errno
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*/
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int gfs2_copy2user(struct buffer_head *bh, char **buf, unsigned int offset,
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unsigned int size)
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{
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int error;
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if (bh)
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error = copy_to_user(*buf, bh->b_data + offset, size);
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else
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error = clear_user(*buf, size);
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if (error)
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error = -EFAULT;
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else
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*buf += size;
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return error;
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}
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static int jdata_read_stuffed(struct gfs2_inode *ip, char *buf,
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unsigned int offset, unsigned int size,
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read_copy_fn_t copy_fn)
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{
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struct buffer_head *dibh;
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int error;
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error = gfs2_meta_inode_buffer(ip, &dibh);
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if (!error) {
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error = copy_fn(dibh, &buf,
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offset + sizeof(struct gfs2_dinode), size);
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brelse(dibh);
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}
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return (error) ? error : size;
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}
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/**
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* gfs2_jdata_read - Read a jdata file
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* @ip: The GFS2 Inode
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* @buf: The buffer to place result into
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* @offset: File offset to begin jdata_readng from
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* @size: Amount of data to transfer
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* @copy_fn: Function to actually perform the copy
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*
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* The @copy_fn only copies a maximum of a single block at once so
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* we are safe calling it with int arguments. It is done so that
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* we don't needlessly put 64bit arguments on the stack and it
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* also makes the code in the @copy_fn nicer too.
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*
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* Returns: The amount of data actually copied or the error
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*/
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int gfs2_jdata_read(struct gfs2_inode *ip, char __user *buf, uint64_t offset,
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unsigned int size, read_copy_fn_t copy_fn)
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{
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struct gfs2_sbd *sdp = ip->i_sbd;
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uint64_t lblock, dblock;
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uint32_t extlen = 0;
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unsigned int o;
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int copied = 0;
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int error = 0;
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if (offset >= ip->i_di.di_size)
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return 0;
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if ((offset + size) > ip->i_di.di_size)
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size = ip->i_di.di_size - offset;
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if (!size)
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return 0;
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if (gfs2_is_stuffed(ip))
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return jdata_read_stuffed(ip, buf, (unsigned int)offset, size,
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copy_fn);
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if (gfs2_assert_warn(sdp, gfs2_is_jdata(ip)))
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return -EINVAL;
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lblock = offset;
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o = do_div(lblock, sdp->sd_jbsize) +
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sizeof(struct gfs2_meta_header);
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while (copied < size) {
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unsigned int amount;
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struct buffer_head *bh;
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int new;
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amount = size - copied;
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if (amount > sdp->sd_sb.sb_bsize - o)
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amount = sdp->sd_sb.sb_bsize - o;
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if (!extlen) {
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new = 0;
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error = gfs2_block_map(ip, lblock, &new,
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&dblock, &extlen);
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if (error)
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goto fail;
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}
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if (extlen > 1)
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gfs2_meta_ra(ip->i_gl, dblock, extlen);
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if (dblock) {
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error = gfs2_jdata_get_buffer(ip, dblock, new, &bh);
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if (error)
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goto fail;
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dblock++;
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extlen--;
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} else
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bh = NULL;
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error = copy_fn(bh, &buf, o, amount);
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brelse(bh);
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if (error)
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goto fail;
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copied += amount;
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lblock++;
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o = sizeof(struct gfs2_meta_header);
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}
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return copied;
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fail:
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return (copied) ? copied : error;
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}
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/**
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* gfs2_copy_from_mem - Trivial copy function for gfs2_jdata_write()
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* @bh: The buffer to copy to or clear
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* @buf: The buffer to copy from
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* @offset: The offset in the buffer to write to
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* @size: The amount of data to write
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*
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* Returns: errno
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*/
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int gfs2_copy_from_mem(struct gfs2_inode *ip, struct buffer_head *bh,
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const char **buf, unsigned int offset, unsigned int size)
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{
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gfs2_trans_add_bh(ip->i_gl, bh, 1);
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memcpy(bh->b_data + offset, *buf, size);
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*buf += size;
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return 0;
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}
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/**
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* gfs2_copy_from_user - Copy bytes from user space for gfs2_jdata_write()
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* @bh: The buffer to copy to or clear
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* @buf: The buffer to copy from
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* @offset: The offset in the buffer to write to
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* @size: The amount of data to write
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*
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* Returns: errno
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*/
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int gfs2_copy_from_user(struct gfs2_inode *ip, struct buffer_head *bh,
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const char __user **buf, unsigned int offset, unsigned int size)
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{
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int error = 0;
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gfs2_trans_add_bh(ip->i_gl, bh, 1);
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if (copy_from_user(bh->b_data + offset, *buf, size))
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error = -EFAULT;
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else
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*buf += size;
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return error;
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}
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static int jdata_write_stuffed(struct gfs2_inode *ip, char *buf,
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unsigned int offset, unsigned int size,
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write_copy_fn_t copy_fn)
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{
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struct buffer_head *dibh;
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int error;
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error = gfs2_meta_inode_buffer(ip, &dibh);
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if (error)
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return error;
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error = copy_fn(ip,
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dibh, &buf,
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offset + sizeof(struct gfs2_dinode), size);
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if (!error) {
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if (ip->i_di.di_size < offset + size)
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ip->i_di.di_size = offset + size;
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ip->i_di.di_mtime = ip->i_di.di_ctime = get_seconds();
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gfs2_dinode_out(&ip->i_di, dibh->b_data);
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}
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brelse(dibh);
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return (error) ? error : size;
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}
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/**
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* gfs2_jdata_write - Write bytes to a file
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* @ip: The GFS2 inode
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* @buf: The buffer containing information to be written
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* @offset: The file offset to start writing at
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* @size: The amount of data to write
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* @copy_fn: Function to do the actual copying
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*
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* Returns: The number of bytes correctly written or error code
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*/
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int gfs2_jdata_write(struct gfs2_inode *ip, const char __user *buf, uint64_t offset,
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unsigned int size, write_copy_fn_t copy_fn)
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{
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struct gfs2_sbd *sdp = ip->i_sbd;
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struct buffer_head *dibh;
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uint64_t lblock, dblock;
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uint32_t extlen = 0;
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unsigned int o;
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int copied = 0;
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int error = 0;
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if (!size)
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return 0;
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if (gfs2_is_stuffed(ip) &&
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offset + size <= sdp->sd_sb.sb_bsize - sizeof(struct gfs2_dinode))
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return jdata_write_stuffed(ip, buf, (unsigned int)offset, size,
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copy_fn);
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if (gfs2_assert_warn(sdp, gfs2_is_jdata(ip)))
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return -EINVAL;
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if (gfs2_is_stuffed(ip)) {
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error = gfs2_unstuff_dinode(ip, NULL, NULL);
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if (error)
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return error;
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}
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lblock = offset;
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o = do_div(lblock, sdp->sd_jbsize) + sizeof(struct gfs2_meta_header);
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while (copied < size) {
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unsigned int amount;
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struct buffer_head *bh;
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int new;
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amount = size - copied;
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if (amount > sdp->sd_sb.sb_bsize - o)
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amount = sdp->sd_sb.sb_bsize - o;
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if (!extlen) {
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new = 1;
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error = gfs2_block_map(ip, lblock, &new,
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&dblock, &extlen);
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if (error)
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goto fail;
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error = -EIO;
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if (gfs2_assert_withdraw(sdp, dblock))
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goto fail;
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}
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error = gfs2_jdata_get_buffer(ip, dblock,
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(amount == sdp->sd_jbsize) ? 1 : new,
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&bh);
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if (error)
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goto fail;
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error = copy_fn(ip, bh, &buf, o, amount);
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brelse(bh);
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if (error)
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goto fail;
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copied += amount;
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lblock++;
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dblock++;
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extlen--;
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o = sizeof(struct gfs2_meta_header);
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}
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out:
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error = gfs2_meta_inode_buffer(ip, &dibh);
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if (error)
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return error;
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if (ip->i_di.di_size < offset + copied)
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ip->i_di.di_size = offset + copied;
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ip->i_di.di_mtime = ip->i_di.di_ctime = get_seconds();
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gfs2_trans_add_bh(ip->i_gl, dibh, 1);
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gfs2_dinode_out(&ip->i_di, dibh->b_data);
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brelse(dibh);
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return copied;
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fail:
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if (copied)
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goto out;
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return error;
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}
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