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465 lines
11 KiB
465 lines
11 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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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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#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 <linux/bio.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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/* |
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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 |
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* to cleanup the other buffers. Don't need to |
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* remove the clustered uptodate information |
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* for this bh as it's not marked locally |
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* uptodate. */ |
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status = -EIO; |
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clear_buffer_needs_validate(bh); |
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goto read_failure; |
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} |
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if (buffer_needs_validate(bh)) { |
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/* We never set NeedsValidate if the |
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* buffer was held by the journal, so |
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* that better not have changed */ |
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BUG_ON(buffer_jbd(bh)); |
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clear_buffer_needs_validate(bh); |
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status = validate(sb, bh); |
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if (status) |
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goto read_failure; |
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} |
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} |
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/* Always set the buffer in the cache, even if it was |
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* a forced read, or read-ahead which hasn't yet |
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* completed. */ |
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ocfs2_set_buffer_uptodate(ci, bh); |
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} |
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ocfs2_metadata_cache_io_unlock(ci); |
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trace_ocfs2_read_blocks_end((unsigned long long)block, nr, |
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flags, ignore_cache); |
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bail: |
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return status; |
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} |
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/* Check whether the blkno is the super block or one of the backups. */ |
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static void ocfs2_check_super_or_backup(struct super_block *sb, |
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sector_t blkno) |
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{ |
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int i; |
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u64 backup_blkno; |
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if (blkno == OCFS2_SUPER_BLOCK_BLKNO) |
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return; |
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for (i = 0; i < OCFS2_MAX_BACKUP_SUPERBLOCKS; i++) { |
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backup_blkno = ocfs2_backup_super_blkno(sb, i); |
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if (backup_blkno == blkno) |
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return; |
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} |
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BUG(); |
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} |
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/* |
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* Write super block and backups doesn't need to collaborate with journal, |
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* so we don't need to lock ip_io_mutex and ci doesn't need to bea passed |
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* into this function. |
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*/ |
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int ocfs2_write_super_or_backup(struct ocfs2_super *osb, |
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struct buffer_head *bh) |
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{ |
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int ret = 0; |
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struct ocfs2_dinode *di = (struct ocfs2_dinode *)bh->b_data; |
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BUG_ON(buffer_jbd(bh)); |
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ocfs2_check_super_or_backup(osb->sb, bh->b_blocknr); |
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if (ocfs2_is_hard_readonly(osb) || ocfs2_is_soft_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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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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ocfs2_compute_meta_ecc(osb->sb, bh->b_data, &di->i_check); |
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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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ret = -EIO; |
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mlog_errno(ret); |
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} |
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out: |
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return ret; |
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}
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