479 lines
12 KiB
C
479 lines
12 KiB
C
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/* -*- mode: c; c-basic-offset: 8; -*-
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* vim: noexpandtab sw=8 ts=8 sts=0:
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*
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* io.c
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*
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* Buffer cache handling
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*
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* Copyright (C) 2002, 2004 Oracle. All rights reserved.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public
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* License along with this program; if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 021110-1307, USA.
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*/
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#include <linux/fs.h>
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#include <linux/types.h>
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#include <linux/highmem.h>
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#include <cluster/masklog.h>
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#include "ocfs2.h"
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#include "alloc.h"
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#include "inode.h"
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#include "journal.h"
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#include "uptodate.h"
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#include "buffer_head_io.h"
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#include "ocfs2_trace.h"
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/*
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* Bits on bh->b_state used by ocfs2.
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*
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* These MUST be after the JBD2 bits. Hence, we use BH_JBDPrivateStart.
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*/
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enum ocfs2_state_bits {
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BH_NeedsValidate = BH_JBDPrivateStart,
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};
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/* Expand the magic b_state functions */
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BUFFER_FNS(NeedsValidate, needs_validate);
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int ocfs2_write_block(struct ocfs2_super *osb, struct buffer_head *bh,
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struct ocfs2_caching_info *ci)
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{
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int ret = 0;
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trace_ocfs2_write_block((unsigned long long)bh->b_blocknr, ci);
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BUG_ON(bh->b_blocknr < OCFS2_SUPER_BLOCK_BLKNO);
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BUG_ON(buffer_jbd(bh));
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/* No need to check for a soft readonly file system here. non
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* journalled writes are only ever done on system files which
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* can get modified during recovery even if read-only. */
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if (ocfs2_is_hard_readonly(osb)) {
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ret = -EROFS;
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mlog_errno(ret);
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goto out;
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}
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ocfs2_metadata_cache_io_lock(ci);
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lock_buffer(bh);
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set_buffer_uptodate(bh);
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/* remove from dirty list before I/O. */
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clear_buffer_dirty(bh);
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get_bh(bh); /* for end_buffer_write_sync() */
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bh->b_end_io = end_buffer_write_sync;
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submit_bh(REQ_OP_WRITE, 0, bh);
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wait_on_buffer(bh);
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if (buffer_uptodate(bh)) {
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ocfs2_set_buffer_uptodate(ci, bh);
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} else {
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/* We don't need to remove the clustered uptodate
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* information for this bh as it's not marked locally
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* uptodate. */
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ret = -EIO;
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mlog_errno(ret);
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}
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ocfs2_metadata_cache_io_unlock(ci);
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out:
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return ret;
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}
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/* Caller must provide a bhs[] with all NULL or non-NULL entries, so it
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* will be easier to handle read failure.
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*/
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int ocfs2_read_blocks_sync(struct ocfs2_super *osb, u64 block,
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unsigned int nr, struct buffer_head *bhs[])
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{
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int status = 0;
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unsigned int i;
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struct buffer_head *bh;
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int new_bh = 0;
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trace_ocfs2_read_blocks_sync((unsigned long long)block, nr);
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if (!nr)
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goto bail;
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/* Don't put buffer head and re-assign it to NULL if it is allocated
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* outside since the caller can't be aware of this alternation!
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*/
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new_bh = (bhs[0] == NULL);
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for (i = 0 ; i < nr ; i++) {
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if (bhs[i] == NULL) {
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bhs[i] = sb_getblk(osb->sb, block++);
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if (bhs[i] == NULL) {
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status = -ENOMEM;
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mlog_errno(status);
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break;
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}
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}
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bh = bhs[i];
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if (buffer_jbd(bh)) {
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trace_ocfs2_read_blocks_sync_jbd(
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(unsigned long long)bh->b_blocknr);
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continue;
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}
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if (buffer_dirty(bh)) {
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/* This should probably be a BUG, or
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* at least return an error. */
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mlog(ML_ERROR,
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"trying to sync read a dirty "
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"buffer! (blocknr = %llu), skipping\n",
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(unsigned long long)bh->b_blocknr);
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continue;
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}
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lock_buffer(bh);
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if (buffer_jbd(bh)) {
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#ifdef CATCH_BH_JBD_RACES
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mlog(ML_ERROR,
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"block %llu had the JBD bit set "
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"while I was in lock_buffer!",
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(unsigned long long)bh->b_blocknr);
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BUG();
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#else
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unlock_buffer(bh);
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continue;
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#endif
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}
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get_bh(bh); /* for end_buffer_read_sync() */
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bh->b_end_io = end_buffer_read_sync;
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submit_bh(REQ_OP_READ, 0, bh);
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}
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read_failure:
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for (i = nr; i > 0; i--) {
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bh = bhs[i - 1];
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if (unlikely(status)) {
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if (new_bh && bh) {
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/* If middle bh fails, let previous bh
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* finish its read and then put it to
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* aovoid bh leak
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*/
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if (!buffer_jbd(bh))
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wait_on_buffer(bh);
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put_bh(bh);
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bhs[i - 1] = NULL;
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} else if (bh && buffer_uptodate(bh)) {
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clear_buffer_uptodate(bh);
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}
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continue;
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}
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/* No need to wait on the buffer if it's managed by JBD. */
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if (!buffer_jbd(bh))
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wait_on_buffer(bh);
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if (!buffer_uptodate(bh)) {
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/* Status won't be cleared from here on out,
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* so we can safely record this and loop back
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* to cleanup the other buffers. */
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status = -EIO;
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goto read_failure;
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}
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}
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bail:
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return status;
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}
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/* Caller must provide a bhs[] with all NULL or non-NULL entries, so it
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* will be easier to handle read failure.
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*/
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int ocfs2_read_blocks(struct ocfs2_caching_info *ci, u64 block, int nr,
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struct buffer_head *bhs[], int flags,
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int (*validate)(struct super_block *sb,
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struct buffer_head *bh))
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{
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int status = 0;
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int i, ignore_cache = 0;
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struct buffer_head *bh;
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struct super_block *sb = ocfs2_metadata_cache_get_super(ci);
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int new_bh = 0;
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trace_ocfs2_read_blocks_begin(ci, (unsigned long long)block, nr, flags);
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BUG_ON(!ci);
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BUG_ON((flags & OCFS2_BH_READAHEAD) &&
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(flags & OCFS2_BH_IGNORE_CACHE));
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if (bhs == NULL) {
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status = -EINVAL;
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mlog_errno(status);
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goto bail;
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}
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if (nr < 0) {
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mlog(ML_ERROR, "asked to read %d blocks!\n", nr);
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status = -EINVAL;
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mlog_errno(status);
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goto bail;
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}
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if (nr == 0) {
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status = 0;
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goto bail;
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}
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/* Don't put buffer head and re-assign it to NULL if it is allocated
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* outside since the caller can't be aware of this alternation!
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*/
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new_bh = (bhs[0] == NULL);
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ocfs2_metadata_cache_io_lock(ci);
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for (i = 0 ; i < nr ; i++) {
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if (bhs[i] == NULL) {
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bhs[i] = sb_getblk(sb, block++);
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if (bhs[i] == NULL) {
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ocfs2_metadata_cache_io_unlock(ci);
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status = -ENOMEM;
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mlog_errno(status);
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/* Don't forget to put previous bh! */
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break;
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}
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}
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bh = bhs[i];
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ignore_cache = (flags & OCFS2_BH_IGNORE_CACHE);
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/* There are three read-ahead cases here which we need to
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* be concerned with. All three assume a buffer has
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* previously been submitted with OCFS2_BH_READAHEAD
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* and it hasn't yet completed I/O.
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*
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* 1) The current request is sync to disk. This rarely
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* happens these days, and never when performance
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* matters - the code can just wait on the buffer
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* lock and re-submit.
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*
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* 2) The current request is cached, but not
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* readahead. ocfs2_buffer_uptodate() will return
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* false anyway, so we'll wind up waiting on the
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* buffer lock to do I/O. We re-check the request
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* with after getting the lock to avoid a re-submit.
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*
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* 3) The current request is readahead (and so must
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* also be a caching one). We short circuit if the
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* buffer is locked (under I/O) and if it's in the
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* uptodate cache. The re-check from #2 catches the
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* case that the previous read-ahead completes just
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* before our is-it-in-flight check.
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*/
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if (!ignore_cache && !ocfs2_buffer_uptodate(ci, bh)) {
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trace_ocfs2_read_blocks_from_disk(
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(unsigned long long)bh->b_blocknr,
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(unsigned long long)ocfs2_metadata_cache_owner(ci));
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/* We're using ignore_cache here to say
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* "go to disk" */
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ignore_cache = 1;
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}
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trace_ocfs2_read_blocks_bh((unsigned long long)bh->b_blocknr,
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ignore_cache, buffer_jbd(bh), buffer_dirty(bh));
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if (buffer_jbd(bh)) {
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continue;
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}
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if (ignore_cache) {
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if (buffer_dirty(bh)) {
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/* This should probably be a BUG, or
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* at least return an error. */
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continue;
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}
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/* A read-ahead request was made - if the
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* buffer is already under read-ahead from a
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* previously submitted request than we are
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* done here. */
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if ((flags & OCFS2_BH_READAHEAD)
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&& ocfs2_buffer_read_ahead(ci, bh))
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continue;
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lock_buffer(bh);
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if (buffer_jbd(bh)) {
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#ifdef CATCH_BH_JBD_RACES
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mlog(ML_ERROR, "block %llu had the JBD bit set "
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"while I was in lock_buffer!",
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(unsigned long long)bh->b_blocknr);
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BUG();
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#else
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unlock_buffer(bh);
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continue;
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#endif
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}
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/* Re-check ocfs2_buffer_uptodate() as a
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* previously read-ahead buffer may have
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* completed I/O while we were waiting for the
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* buffer lock. */
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if (!(flags & OCFS2_BH_IGNORE_CACHE)
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&& !(flags & OCFS2_BH_READAHEAD)
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&& ocfs2_buffer_uptodate(ci, bh)) {
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unlock_buffer(bh);
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continue;
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}
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get_bh(bh); /* for end_buffer_read_sync() */
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if (validate)
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set_buffer_needs_validate(bh);
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bh->b_end_io = end_buffer_read_sync;
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submit_bh(REQ_OP_READ, 0, bh);
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continue;
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}
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}
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read_failure:
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for (i = (nr - 1); i >= 0; i--) {
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bh = bhs[i];
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if (!(flags & OCFS2_BH_READAHEAD)) {
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if (unlikely(status)) {
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/* Clear the buffers on error including those
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* ever succeeded in reading
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*/
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if (new_bh && bh) {
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/* If middle bh fails, let previous bh
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* finish its read and then put it to
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* aovoid bh leak
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*/
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if (!buffer_jbd(bh))
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wait_on_buffer(bh);
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put_bh(bh);
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bhs[i] = NULL;
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} else if (bh && buffer_uptodate(bh)) {
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clear_buffer_uptodate(bh);
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}
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continue;
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}
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/* We know this can't have changed as we hold the
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* owner sem. Avoid doing any work on the bh if the
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* journal has it. */
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if (!buffer_jbd(bh))
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wait_on_buffer(bh);
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if (!buffer_uptodate(bh)) {
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/* Status won't be cleared from here on out,
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|
|
* so we can safely record this and loop back
|
||
|
|
* to cleanup the other buffers. Don't need to
|
||
|
|
* remove the clustered uptodate information
|
||
|
|
* for this bh as it's not marked locally
|
||
|
|
* uptodate. */
|
||
|
|
status = -EIO;
|
||
|
|
clear_buffer_needs_validate(bh);
|
||
|
|
goto read_failure;
|
||
|
|
}
|
||
|
|
|
||
|
|
if (buffer_needs_validate(bh)) {
|
||
|
|
/* We never set NeedsValidate if the
|
||
|
|
* buffer was held by the journal, so
|
||
|
|
* that better not have changed */
|
||
|
|
BUG_ON(buffer_jbd(bh));
|
||
|
|
clear_buffer_needs_validate(bh);
|
||
|
|
status = validate(sb, bh);
|
||
|
|
if (status)
|
||
|
|
goto read_failure;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
/* Always set the buffer in the cache, even if it was
|
||
|
|
* a forced read, or read-ahead which hasn't yet
|
||
|
|
* completed. */
|
||
|
|
ocfs2_set_buffer_uptodate(ci, bh);
|
||
|
|
}
|
||
|
|
ocfs2_metadata_cache_io_unlock(ci);
|
||
|
|
|
||
|
|
trace_ocfs2_read_blocks_end((unsigned long long)block, nr,
|
||
|
|
flags, ignore_cache);
|
||
|
|
|
||
|
|
bail:
|
||
|
|
|
||
|
|
return status;
|
||
|
|
}
|
||
|
|
|
||
|
|
/* Check whether the blkno is the super block or one of the backups. */
|
||
|
|
static void ocfs2_check_super_or_backup(struct super_block *sb,
|
||
|
|
sector_t blkno)
|
||
|
|
{
|
||
|
|
int i;
|
||
|
|
u64 backup_blkno;
|
||
|
|
|
||
|
|
if (blkno == OCFS2_SUPER_BLOCK_BLKNO)
|
||
|
|
return;
|
||
|
|
|
||
|
|
for (i = 0; i < OCFS2_MAX_BACKUP_SUPERBLOCKS; i++) {
|
||
|
|
backup_blkno = ocfs2_backup_super_blkno(sb, i);
|
||
|
|
if (backup_blkno == blkno)
|
||
|
|
return;
|
||
|
|
}
|
||
|
|
|
||
|
|
BUG();
|
||
|
|
}
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Write super block and backups doesn't need to collaborate with journal,
|
||
|
|
* so we don't need to lock ip_io_mutex and ci doesn't need to bea passed
|
||
|
|
* into this function.
|
||
|
|
*/
|
||
|
|
int ocfs2_write_super_or_backup(struct ocfs2_super *osb,
|
||
|
|
struct buffer_head *bh)
|
||
|
|
{
|
||
|
|
int ret = 0;
|
||
|
|
struct ocfs2_dinode *di = (struct ocfs2_dinode *)bh->b_data;
|
||
|
|
|
||
|
|
BUG_ON(buffer_jbd(bh));
|
||
|
|
ocfs2_check_super_or_backup(osb->sb, bh->b_blocknr);
|
||
|
|
|
||
|
|
if (ocfs2_is_hard_readonly(osb) || ocfs2_is_soft_readonly(osb)) {
|
||
|
|
ret = -EROFS;
|
||
|
|
mlog_errno(ret);
|
||
|
|
goto out;
|
||
|
|
}
|
||
|
|
|
||
|
|
lock_buffer(bh);
|
||
|
|
set_buffer_uptodate(bh);
|
||
|
|
|
||
|
|
/* remove from dirty list before I/O. */
|
||
|
|
clear_buffer_dirty(bh);
|
||
|
|
|
||
|
|
get_bh(bh); /* for end_buffer_write_sync() */
|
||
|
|
bh->b_end_io = end_buffer_write_sync;
|
||
|
|
ocfs2_compute_meta_ecc(osb->sb, bh->b_data, &di->i_check);
|
||
|
|
submit_bh(REQ_OP_WRITE, 0, bh);
|
||
|
|
|
||
|
|
wait_on_buffer(bh);
|
||
|
|
|
||
|
|
if (!buffer_uptodate(bh)) {
|
||
|
|
ret = -EIO;
|
||
|
|
mlog_errno(ret);
|
||
|
|
}
|
||
|
|
|
||
|
|
out:
|
||
|
|
return ret;
|
||
|
|
}
|