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Diffstat (limited to 'fs/ocfs2/buffer_head_io.c')
-rw-r--r--fs/ocfs2/buffer_head_io.c429
1 files changed, 429 insertions, 0 deletions
diff --git a/fs/ocfs2/buffer_head_io.c b/fs/ocfs2/buffer_head_io.c
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+++ b/fs/ocfs2/buffer_head_io.c
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+/* -*- 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;
+ put_bh(bh);
+ 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;
+ put_bh(bh);
+ mlog_errno(ret);
+ }
+
+out:
+ return ret;
+}
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