mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-11-30 11:56:43 +07:00
491e94f790
This patch fixes a timing window that causes a segfault. The problem is that bd can remain NULL throughout the function and then reference that NULL pointer if the bh->b_private starts out NULL, then someone sets it to non-NULL inside the locking. In that case, bd still needs to be set. Signed-off-by: Bob Peterson <rpeterso@redhat.com>
284 lines
7.3 KiB
C
284 lines
7.3 KiB
C
/*
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* Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
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* Copyright (C) 2004-2006 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 version 2.
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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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 <linux/kallsyms.h>
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#include <linux/gfs2_ondisk.h>
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#include "gfs2.h"
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#include "incore.h"
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#include "glock.h"
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#include "inode.h"
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#include "log.h"
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#include "lops.h"
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#include "meta_io.h"
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#include "trans.h"
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#include "util.h"
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#include "trace_gfs2.h"
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int gfs2_trans_begin(struct gfs2_sbd *sdp, unsigned int blocks,
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unsigned int revokes)
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{
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struct gfs2_trans *tr;
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int error;
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BUG_ON(current->journal_info);
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BUG_ON(blocks == 0 && revokes == 0);
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if (!test_bit(SDF_JOURNAL_LIVE, &sdp->sd_flags))
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return -EROFS;
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tr = kzalloc(sizeof(struct gfs2_trans), GFP_NOFS);
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if (!tr)
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return -ENOMEM;
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tr->tr_ip = _RET_IP_;
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tr->tr_blocks = blocks;
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tr->tr_revokes = revokes;
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tr->tr_reserved = 1;
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tr->tr_alloced = 1;
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if (blocks)
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tr->tr_reserved += 6 + blocks;
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if (revokes)
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tr->tr_reserved += gfs2_struct2blk(sdp, revokes,
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sizeof(u64));
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INIT_LIST_HEAD(&tr->tr_databuf);
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INIT_LIST_HEAD(&tr->tr_buf);
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sb_start_intwrite(sdp->sd_vfs);
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error = gfs2_log_reserve(sdp, tr->tr_reserved);
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if (error)
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goto fail;
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current->journal_info = tr;
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return 0;
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fail:
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sb_end_intwrite(sdp->sd_vfs);
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kfree(tr);
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return error;
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}
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static void gfs2_print_trans(const struct gfs2_trans *tr)
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{
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pr_warn("Transaction created at: %pSR\n", (void *)tr->tr_ip);
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pr_warn("blocks=%u revokes=%u reserved=%u touched=%u\n",
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tr->tr_blocks, tr->tr_revokes, tr->tr_reserved, tr->tr_touched);
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pr_warn("Buf %u/%u Databuf %u/%u Revoke %u/%u\n",
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tr->tr_num_buf_new, tr->tr_num_buf_rm,
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tr->tr_num_databuf_new, tr->tr_num_databuf_rm,
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tr->tr_num_revoke, tr->tr_num_revoke_rm);
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}
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void gfs2_trans_end(struct gfs2_sbd *sdp)
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{
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struct gfs2_trans *tr = current->journal_info;
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s64 nbuf;
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int alloced = tr->tr_alloced;
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BUG_ON(!tr);
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current->journal_info = NULL;
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if (!tr->tr_touched) {
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gfs2_log_release(sdp, tr->tr_reserved);
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if (alloced) {
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kfree(tr);
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sb_end_intwrite(sdp->sd_vfs);
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}
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return;
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}
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nbuf = tr->tr_num_buf_new + tr->tr_num_databuf_new;
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nbuf -= tr->tr_num_buf_rm;
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nbuf -= tr->tr_num_databuf_rm;
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if (gfs2_assert_withdraw(sdp, (nbuf <= tr->tr_blocks) &&
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(tr->tr_num_revoke <= tr->tr_revokes)))
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gfs2_print_trans(tr);
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gfs2_log_commit(sdp, tr);
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if (alloced && !tr->tr_attached)
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kfree(tr);
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up_read(&sdp->sd_log_flush_lock);
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if (sdp->sd_vfs->s_flags & MS_SYNCHRONOUS)
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gfs2_log_flush(sdp, NULL, NORMAL_FLUSH);
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if (alloced)
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sb_end_intwrite(sdp->sd_vfs);
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}
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static struct gfs2_bufdata *gfs2_alloc_bufdata(struct gfs2_glock *gl,
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struct buffer_head *bh,
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const struct gfs2_log_operations *lops)
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{
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struct gfs2_bufdata *bd;
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bd = kmem_cache_zalloc(gfs2_bufdata_cachep, GFP_NOFS | __GFP_NOFAIL);
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bd->bd_bh = bh;
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bd->bd_gl = gl;
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bd->bd_ops = lops;
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INIT_LIST_HEAD(&bd->bd_list);
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bh->b_private = bd;
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return bd;
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}
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/**
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* gfs2_trans_add_data - Add a databuf to the transaction.
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* @gl: The inode glock associated with the buffer
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* @bh: The buffer to add
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*
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* This is used in two distinct cases:
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* i) In ordered write mode
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* We put the data buffer on a list so that we can ensure that its
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* synced to disk at the right time
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* ii) In journaled data mode
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* We need to journal the data block in the same way as metadata in
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* the functions above. The difference is that here we have a tag
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* which is two __be64's being the block number (as per meta data)
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* and a flag which says whether the data block needs escaping or
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* not. This means we need a new log entry for each 251 or so data
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* blocks, which isn't an enormous overhead but twice as much as
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* for normal metadata blocks.
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*/
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void gfs2_trans_add_data(struct gfs2_glock *gl, struct buffer_head *bh)
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{
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struct gfs2_trans *tr = current->journal_info;
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struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
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struct address_space *mapping = bh->b_page->mapping;
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struct gfs2_inode *ip = GFS2_I(mapping->host);
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struct gfs2_bufdata *bd;
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if (!gfs2_is_jdata(ip)) {
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gfs2_ordered_add_inode(ip);
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return;
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}
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lock_buffer(bh);
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gfs2_log_lock(sdp);
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bd = bh->b_private;
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if (bd == NULL) {
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gfs2_log_unlock(sdp);
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unlock_buffer(bh);
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if (bh->b_private == NULL)
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bd = gfs2_alloc_bufdata(gl, bh, &gfs2_databuf_lops);
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else
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bd = bh->b_private;
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lock_buffer(bh);
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gfs2_log_lock(sdp);
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}
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gfs2_assert(sdp, bd->bd_gl == gl);
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tr->tr_touched = 1;
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if (list_empty(&bd->bd_list)) {
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set_bit(GLF_LFLUSH, &bd->bd_gl->gl_flags);
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set_bit(GLF_DIRTY, &bd->bd_gl->gl_flags);
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gfs2_pin(sdp, bd->bd_bh);
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tr->tr_num_databuf_new++;
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list_add_tail(&bd->bd_list, &tr->tr_databuf);
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}
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gfs2_log_unlock(sdp);
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unlock_buffer(bh);
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}
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static void meta_lo_add(struct gfs2_sbd *sdp, struct gfs2_bufdata *bd)
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{
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struct gfs2_meta_header *mh;
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struct gfs2_trans *tr;
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enum gfs2_freeze_state state = atomic_read(&sdp->sd_freeze_state);
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tr = current->journal_info;
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tr->tr_touched = 1;
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if (!list_empty(&bd->bd_list))
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return;
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set_bit(GLF_LFLUSH, &bd->bd_gl->gl_flags);
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set_bit(GLF_DIRTY, &bd->bd_gl->gl_flags);
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mh = (struct gfs2_meta_header *)bd->bd_bh->b_data;
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if (unlikely(mh->mh_magic != cpu_to_be32(GFS2_MAGIC))) {
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pr_err("Attempting to add uninitialised block to journal (inplace block=%lld)\n",
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(unsigned long long)bd->bd_bh->b_blocknr);
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BUG();
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}
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if (unlikely(state == SFS_FROZEN)) {
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printk(KERN_INFO "GFS2:adding buf while frozen\n");
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gfs2_assert_withdraw(sdp, 0);
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}
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gfs2_pin(sdp, bd->bd_bh);
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mh->__pad0 = cpu_to_be64(0);
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mh->mh_jid = cpu_to_be32(sdp->sd_jdesc->jd_jid);
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list_add(&bd->bd_list, &tr->tr_buf);
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tr->tr_num_buf_new++;
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}
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void gfs2_trans_add_meta(struct gfs2_glock *gl, struct buffer_head *bh)
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{
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struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
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struct gfs2_bufdata *bd;
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lock_buffer(bh);
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gfs2_log_lock(sdp);
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bd = bh->b_private;
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if (bd == NULL) {
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gfs2_log_unlock(sdp);
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unlock_buffer(bh);
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lock_page(bh->b_page);
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if (bh->b_private == NULL)
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bd = gfs2_alloc_bufdata(gl, bh, &gfs2_buf_lops);
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else
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bd = bh->b_private;
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unlock_page(bh->b_page);
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lock_buffer(bh);
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gfs2_log_lock(sdp);
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}
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gfs2_assert(sdp, bd->bd_gl == gl);
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meta_lo_add(sdp, bd);
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gfs2_log_unlock(sdp);
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unlock_buffer(bh);
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}
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void gfs2_trans_add_revoke(struct gfs2_sbd *sdp, struct gfs2_bufdata *bd)
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{
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struct gfs2_trans *tr = current->journal_info;
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BUG_ON(!list_empty(&bd->bd_list));
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gfs2_add_revoke(sdp, bd);
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tr->tr_touched = 1;
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tr->tr_num_revoke++;
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}
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void gfs2_trans_add_unrevoke(struct gfs2_sbd *sdp, u64 blkno, unsigned int len)
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{
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struct gfs2_bufdata *bd, *tmp;
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struct gfs2_trans *tr = current->journal_info;
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unsigned int n = len;
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gfs2_log_lock(sdp);
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list_for_each_entry_safe(bd, tmp, &sdp->sd_log_le_revoke, bd_list) {
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if ((bd->bd_blkno >= blkno) && (bd->bd_blkno < (blkno + len))) {
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list_del_init(&bd->bd_list);
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gfs2_assert_withdraw(sdp, sdp->sd_log_num_revoke);
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sdp->sd_log_num_revoke--;
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kmem_cache_free(gfs2_bufdata_cachep, bd);
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tr->tr_num_revoke_rm++;
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if (--n == 0)
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break;
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}
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}
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gfs2_log_unlock(sdp);
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}
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