Initial import

1 files changed, 427 insertions, 0 deletions

diff --git a/fs/ocfs2/buffer_head_io.c b/fs/ocfs2/buffer_head_io.c
new file mode 100644
index 000000000..1edcb141f
--- /dev/null
+++ b/fs/ocfs2/buffer_head_io.c
@@ -0,0 +1,427 @@
+/* -*- 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 = -ENOMEM;
+				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 = -ENOMEM;
+				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;
+}