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